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1.
  • Villnäs, Anna, et al. (författare)
  • Changes in macrofaunal biological traits across estuarine gradients : implications for the coastal nutrient filter
  • 2019
  • Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 622, s. 31-48
  • Tidskriftsartikel (refereegranskat)abstract
    • Benthic macrofaunal communities have a profound impact on organic matter turnover and nutrient cycling in marine sediments. Their activities are of particular importance in the coastal filter, where nutrients and organic matter from land are transformed and/or retained before reaching the open sea. The benthic fauna modify the coastal filter directly (through consumption, respiration, excretion and biomass production) and indirectly (through bioturbation). It is hard to experimentally quantify faunal contribution to the coastal filter over large spatial and temporal scales that encompass significant environmental and biological heterogeneity. However, estimates can be obtained with biological trait analyses. By using benthic biological traits, we explored how the potential contribution of macrofaunal communities to the coastal filter differ between inner and outer sites in an extensive archipelago area and examine the generality of the observed pattern across contrasting coastal areas of the entire Baltic Sea. Estimates of benthic bioturbation, longevity and size (i.e. 'stability') and total energy and nutrient contents differed between coastal areas and inner versus outer sites. Benthic traits indicative of an enhanced nutrient turnover but a decreased capacity for temporal nutrient retention dominated inner sites, while outer sites were often dominated by larger individuals, exhibiting traits that are likely to enhance nutrient uptake and retention. The overarching similarities in benthic trait expression between more eutrophied inner vs. less affected outer coastal sites across the Baltic Sea suggest that benthic communities might contribute in a similar manner to nutrient recycling and retention in the coastal filter over large geographical scales.
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2.
  • Andersen, Jesper H., et al. (författare)
  • Long-term temporal and spatial trends in eutrophication status of the Baltic Sea
  • 2017
  • Ingår i: Biological Reviews. - : Wiley. - 1464-7931 .- 1469-185X. ; 92:1, s. 135-149
  • Tidskriftsartikel (refereegranskat)abstract
    • Much of the Baltic Sea is currently classified as 'affected by eutrophication'. The causes for this are twofold. First, current levels of nutrient inputs (nitrogen and phosphorus) from human activities exceed the natural processing capacity with an accumulation of nutrients in the Baltic Sea over the last 50-100 years. Secondly, the Baltic Sea is naturally susceptible to nutrient enrichment due to a combination of long retention times and stratification restricting ventilation of deep waters. Here, based on a unique data set collated from research activities and long-term monitoring programs, we report on the temporal and spatial trends of eutrophication status for the open Baltic Sea over a 112-year period using the HELCOM Eutrophication Assessment Tool (HEAT 3.0). Further, we analyse variation in the confidence of the eutrophication status assessment based on a systematic quantitative approach using coefficients of variation in the observations. The classifications in our assessment indicate that the first signs of eutrophication emerged in the mid-1950s and the central parts of the Baltic Sea changed from being unaffected by eutrophication to being affected. We document improvements in eutrophication status that are direct consequences of long-term efforts to reduce the inputs of nutrients. The reductions in both nitrogen and phosphorus loads have led to large-scale alleviation of eutrophication and to a healthier Baltic Sea. Reduced confidence in our assessment is seen more recently due to reductions in the scope of monitoring programs. Our study sets a baseline for implementation of the ecosystem-based management strategies and policies currently in place including the EU Marine Strategy Framework Directives and the HELCOM Baltic Sea Action Plan.
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3.
  • Attard, Karl M., et al. (författare)
  • Seasonal ecosystem metabolism across shallow benthic habitats measured by aquatic eddy covariance
  • 2019
  • Ingår i: Limnology and Oceanography Letters. - : Wiley. - 2378-2242. ; 4:3, s. 79-86
  • Tidskriftsartikel (refereegranskat)abstract
    • Shallow benthic habitats are hotspots for carbon cycling and energy flow, but metabolism (primary production and respiration) dynamics and habitat-specific differences remain poorly understood. We investigated daily, seasonal, and annual metabolism in six key benthic habitats in the Baltic Sea using similar to 2900h of in situ aquatic eddy covariance oxygen flux measurements. Rocky substrates had the highest metabolism rates. Habitat-specific annual primary production per m(2) was in the order Fucus vesiculosus canopy>Mytilus trossulus reef>Zostera marina canopy>mixed macrophytes canopy>sands, whereas respiration was in the order M. trossulus>F. vesiculosus>Z. marina>mixed macrophytes> sands>aphotic sediments. Winter metabolism contributed 22-31% of annual rates. Spatial upscaling revealed that benthic habitats drive >90% of ecosystem metabolism in waters <= 5 m depth, highlighting their central role in carbon and nutrient cycling in shallow waters.
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4.
  • Attard, K. M., et al. (författare)
  • Seasonal metabolism and carbon export potential of a key coastal habitat : The perennial canopy-forming macroalga Fucus vesiculosus
  • 2019
  • Ingår i: Limnology and Oceanography. - : Wiley. - 0024-3590 .- 1939-5590. ; 64:1, s. 149-164
  • Tidskriftsartikel (refereegranskat)abstract
    • The important role of macroalgal canopies in the oceanic carbon (C) cycle is increasingly being recognized, but direct assessments of community productivity remain scarce. We conducted a seasonal study on a sublittoral Baltic Sea canopy of the brown alga Fucus vesiculosus, a prominent species in temperate and Arctic waters. We investigated community production on hourly, daily, and seasonal timescales. Aquatic eddy covariance (AEC) oxygen flux measurements integrated similar to 40 m(2) of the seabed surface area and documented considerable oxygen production by the canopy year-round. High net oxygen production rates of up to 35 +/- 9 mmol m(-2) h(-1) were measured under peak irradiance of similar to 1200 mu mol photosynthetically active radiation (PAR) m(-2) s(-1) in summer. However, high rates > 15 mmol m(-2) h(-1) were also measured in late winter (March) under low light intensities < 250 mu mol PAR m(-2) s(-1) and water temperatures of similar to 1 degrees C. In some cases, hourly AEC fluxes documented an apparent release of oxygen by the canopy under dark conditions, which may be due to gas storage dynamics within internal air spaces of F. vesiculosus. Daily net ecosystem metabolism (NEM) was positive (net autotrophic) in all but one of the five measurement campaigns (December). A simple regression model predicted a net autotrophic canopy for two-thirds of the year, and annual canopy NEM amounted to 25 mol O-2 m(-2) yr(-1), approximately six-fold higher than net phytoplankton production. Canopy C export was similar to 0.3 kg C m(-2) yr(-1), comparable to canopy standing biomass in summer. Macroalgal canopies thus represent regions of intensified C assimilation and export in coastal waters.
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5.
  • Bernard, Guillaume, et al. (författare)
  • Quantifying bioturbation across coastal seascapes : Habitat characteristics modify effects of macrofaunal communities
  • 2019
  • Ingår i: Journal of Sea Research. - : Elsevier BV. - 1385-1101 .- 1873-1414. ; 152
  • Tidskriftsartikel (refereegranskat)abstract
    • Bioturbation by benthic macrofauna communities plays a significant role in the setting and maintenance of important ecosystem functions and the delivery of associated ecosystem services. We investigated the context dependence of bioturbation performed by natural benthic communities in the coastal northern Baltic Sea by quantifying three bioturbation metrics (particle mixing intensity, surface sediment reworking and bioturbation depth) across 18 sites ranging from cohesive muddy sediments to non-cohesive coarse sands, while accounting for the complexity of natural communities and habitat characteristics. We identified two distinct patterns of bioturbation; in fine sediments bioturbation rates were highly variable and in coarse sediments bioturbation rates were less variable and characterized by lower maximal values. Using distance-based linear multiple regressions, we found that 75.5% of the variance in bioturbation rates in fine sediment could be explained by key functional groups/species abundance and/or biomass (i.e. biomass of the gallery-diffusors and abundances of biodiffusors, surface modifiers, conveyors and gallery diffusors, respectively). In coarse sediment, 47.8% of the variance in bioturbation rates could be explained by a combination of environmental factors (grain size, organic matter content, buried plant material) and faunal functional groups, although fauna alone explained only 13% of this variance. Bioturbation in fine sediments was therefore more predictable based on the composition of benthic fauna. In coarse sediment, the bioturbation activities of benthic fauna were strongly modified by habitat characteristics (including the presence of buried plant material, sediment organic content and grain size) whereas in fine sediments this was not the case. Our results therefore highlight that variability in spatial patterns of bioturbation is a result of complex relationships between macrofauna community structure, sediment type and other habitat characteristics, likely modifying bioturbation performance of individual fauna.
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6.
  • Carstensen, Jacob, et al. (författare)
  • Hypoxia in the Baltic Sea : Biogeochemical Cycles, Benthic Fauna, and Management
  • 2014
  • Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 43:1, s. 26-36
  • Tidskriftsartikel (refereegranskat)abstract
    • Hypoxia has occurred intermittently over the Holocene in the Baltic Sea, but the recent expansion from less than 10 000 km(2) before 1950 to > 60 000 km(2) since 2000 is mainly caused by enhanced nutrient inputs from land and atmosphere. With worsening hypoxia, the role of sediments changes from nitrogen removal to nitrogen release as ammonium. At present, denitrification in the water column and sediments is equally important. Phosphorus is currently buried in sediments mainly in organic form, with an additional contribution of reduced Fe-phosphate minerals in the deep anoxic basins. Upon the transition to oxic conditions, a significant proportion of the organic phosphorus will be remineralized, with the phosphorus then being bound to iron oxides. This iron-oxide bound phosphorus is readily released to the water column upon the onset of hypoxia again. Important ecosystems services carried out by the benthic fauna, including biogeochemical feedback-loops and biomass production, are also lost with hypoxia. The results provide quantitative knowledge of nutrient release and recycling processes under various environmental conditions in support of decision support tools underlying the Baltic Sea Action Plan.
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7.
  • Eriksson, Susanne P., 1964, et al. (författare)
  • Episodic disturbance events modify predator-prey interactions in soft sediments
  • 2005
  • Ingår i: Estuarine Coastal and Shelf Science. - : Elsevier BV. - 0272-7714. ; 64:2-3, s. 289-294
  • Tidskriftsartikel (refereegranskat)abstract
    • Physical disturbance events are common in shallow soft-sediment habitats and can have significant effects on predator-prey interactions. While several studies have reported on predator aggregations following disturbance events, few studies have investigated the mechanisms and interactive effects of predation and physical disturbance on prey survival in shallow soft-sediment habitats. In this study the interactive effects of sediment resuspension and predation by two contrasting epibenthic predator species were tested on the survival of the amphipod Corophium volutator in a laboratory experiment. The shrimp Crangon crangon and juvenile plaice Pleuronectes platessa were used as predators, both numerical dominants in shallow soft sediments on the Swedish west coast. In addition we quantified epibenthic predator aggregation in the field following small-scale disturbances. In the laboratory, synergistic negative effects of predation and non-lethal disturbance on Corophium survival were found with both predator species, and rapid aggregation of several mobile epibenthic predator species following disturbance was demonstrated in the field. Abundances of C. crangon, the numerically dominant predator in the field, were doubled in disturbed patches within 2 min following disturbance. Our study emphasises the importance of considering episodic small-scale disturbances when interpreting predation effects and trophic interactions in shallow soft-sediment systems. (c) 2005 Elsevier Ltd. All rights reserved.
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8.
  • Gammal, Johanna, et al. (författare)
  • Does the use of biological traits predict a smooth landscape of ecosystem functioning?
  • 2020
  • Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 10:19, s. 10395-10407
  • Tidskriftsartikel (refereegranskat)abstract
    • The biodiversity crisis has increased interest in understanding the role of biodiversity for ecosystem functioning. Functional traits are often used to infer ecosystem functions to increase our understanding of these relationships over larger spatial scales. The links between specific traits and ecosystem functioning are, however, not always well established. We investigated how the choice of analyzing either individual species, selected modalities, or trait combinations affected the spatial patterns observed on a sandflat and how this was related to the natural variability in ecosystem functioning. A large dataset of 400 benthic macrofauna samples was used to explore distribution patterns. We hypothesized that (1) if multiple species (redundancy) represent a trait combination or a modality their spatial patterns would be smoothed out, and (2) the lost spatial variability within a trait combination or modality, due to the smoothing effect, would potentially affect their utility for predicting ecosystem functioning (tested on a dataset of 24 samples). We predicted that species would show heterogeneous small spatial patterns, while modalities and trait combinations would show larger and more homogeneous patterns because they would represent a collection of many distributions. If modalities and trait combinations are better predictors of ecosystem functioning than species, then the smoother spatial patterns of modalities and trait combinations would result in a more homogeneous landscape of ecosystem function and the number of species exhibiting specific traits would provide functional redundancy. Our results showed some smoothing of spatial patterns progressing from species through modalities to trait combinations, but generally spatial patterns reflected a few dominant key species. Moreover, some individual modalities and species explained more or equal proportions of the variance in the ecosystem functioning than the combined traits. The findings thus suggest that only some spatial variability is lost when species are combined into modalities and trait combinations and that a homogeneous landscape of ecosystem function is not likely.
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9.
  • Gammal, Johanna, et al. (författare)
  • Environmental Context Mediates Biodiversity–Ecosystem Functioning Relationships in Coastal Soft-sediment Habitats
  • 2019
  • Ingår i: Ecosystems (New York. Print). - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 22:1, s. 137-151
  • Tidskriftsartikel (refereegranskat)abstract
    • The ongoing loss of biodiversity and global environmental changes severely affect the structure of coastal ecosystems. Consequences, in terms of ecosystem functioning, are, however, difficult to predict because the context dependency of the biodiversity–ecosystem function relationships within these heterogeneous seascapes is poorly understood. To assess the effects of biological and environmental factors in mediating ecosystem functioning (nutrient cycling) in different natural habitats, intact sediment cores were collected at 18 sites on a grain size gradient from coarse sand to silt, with varying organic matter content and vegetation. To assess ecosystem functioning, solute fluxes (O2, NH4+, PO43−, Si) across the sediment–water interface were measured. The macrofaunal communities changed along the grain size gradient with higher abundance, biomass and number of species in coarser sediments and in habitats with more vegetation. Across the whole gradient, the macrofauna cumulatively accounted for 25% of the variability in the multivariate solute fluxes, whereas environmental variables cumulatively accounted for 20%. Only the biomass and abundance of a few of the most dominant macrofauna species, not the number of species, appeared to contribute significantly to the nutrient recycling processes. Closer analyses of different sediment types (grouped into coarse, medium and fine sediment) showed that the macrofauna was an important predictor in all sediment types, but had the largest impact in fine and medium sediments. The results imply that even if the ecosystem functioning is similar in different sediment types, the underpinning mechanisms are different, which makes it challenging to generalize patterns of functioning across the heterogeneous shallow coastal zones.
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10.
  • Goebeler, Norman, et al. (författare)
  • Ninety years of coastal monitoring reveals baseline and extreme ocean temperatures are increasing off the Finnish coast
  • 2022
  • Ingår i: Communications Earth & Environment. - : Springer Science and Business Media LLC. - 2662-4435. ; 3:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Long term coastal surface and sub-surface monitoring reveals that warm temperature extremes have intensified and cold extremes nearly vanished in the last decades, increasing baseline water temperature on the southwest coast of Finland. Global marine heatwave assessments often rely on satellite-derived sea surface temperature. However, these data have low accuracy in coastal areas, are unable to measure sub-surface temperatures and have only been available since the 1980s. Here, we analyse 90 years of in situ surface and bottom (30 m) water temperature data from a Finnish coastal monitoring site. Water temperatures were significantly higher between 1991-2020 than 1931-1960 and 1961-1990. We find strong differences between satellite-derived and in situ temperatures, with in situ temperatures being lower in autumn and winter and higher in spring. Measurements at the seafloor indicate marine heatwaves occurred during all seasons between 2016 and 2020, with intensities and durations exceeding previous records. Since the 1990s, we find an upward shift of the baseline temperature and increasingly frequent occurrence of temperatures previously considered as an extreme. Our findings highlight the importance of long-term in situ data and choice of climatological reference periods for assessing change.
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11.
  • Humborg, Christoph, et al. (författare)
  • High Emissions of Carbon Dioxide and Methane From the Coastal Baltic Sea at the End of a Summer Heat Wave
  • 2019
  • Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 6
  • Tidskriftsartikel (refereegranskat)abstract
    • The summer heat wave in 2018 led to the highest recorded water temperatures since 1926 - up to 21 degrees C - in bottom coastal waters of the Baltic Sea, with implications for the respiration patterns in these shallow coastal systems. We applied cavity ring-down spectrometer measurements to continuously monitor carbon dioxide (CO2) and methane (CH4) surface-water concentrations, covering the coastal archipelagos of Sweden and Finland and the open and deeper parts of the Northern Baltic Proper. This allowed us to (i) follow an upwelling event near the Swedish coast leading to elevated CO2 and moderate CH 4 outgassing, and (ii) to estimate CH4 sources and fluxes along the coast by investigating water column inventories and air-sea fluxes during a storm and an associated downwelling event. At the end of the heat wave, before the storm event, we found elevated CO2 (1583 mu atm) and CH4 (70 nmol/L) concentrations. During the storm, a massive CO2 sea-air flux of up to 274 mmol m(-2) d(-1) was observed. While water-column CO2 concentrations were depleted during several hours of the storm, CH4 concentrations remained elevated. Overall, we found a positive relationship between CO2 and CH4 wind-driven sea-air fluxes, however, the highest CH4 fluxes were observed at low winds whereas highest CO2 fluxes were during peak winds, suggesting different sources and processes controlling their fluxes besides wind. We applied a box-model approach to estimate the CH4 supply needed to sustain these elevated CH4 concentrations and the results suggest a large source flux of CH4 to the water column of 2.5 mmol m(-2) d(-1). These results are qualitatively supported by acoustic observations of vigorous and widespread outgassing from the sediments, with flares that could be traced throughout the water column penetrating the pycnocline and reaching the sea surface. The results suggest that the heat wave triggered CO2 and CH4 fluxes in the coastal zones that are comparable with maximum emission rates found in other hot spots, such as boreal and arctic lakes and wetlands. Further, the results suggest that heat waves are as important for CO2 and CH4 sea-air fluxes as the ice break up in spring.
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12.
  • Jakobsson, Martin, et al. (författare)
  • Potential links between Baltic Sea submarine terraces and groundwater seeping
  • 2020
  • Ingår i: Earth Surface Dynamics. - : Copernicus GmbH. - 2196-6311 .- 2196-632X. ; 8:1, s. 1-15
  • Tidskriftsartikel (refereegranskat)abstract
    • Submarine groundwater discharge (SGD) influences ocean chemistry, circulation, and the spreading of nutrients and pollutants; it also shapes sea floor morphology. In the Baltic Sea, SGD was linked to the development of terraces and semicircular depressions mapped in an area of the southern Stockholm archipelago, Sweden, in the 1990s. We mapped additional parts of the Stockholm archipelago, areas in Blekinge, southern Sweden, and southern Finland using high-resolution multibeam sonars and sub-bottom profilers to investigate if the sea floor morphological features discovered in the 1990s are widespread and to further address the hypothesis linking their formation to SGD. Sediment coring and sea floor photography conducted with a remotely operated vehicle (ROV) and divers add additional information to the geophysical mapping results. We find that terraces, with general bathymetric expressions of about 1 m and lateral extents of sometimes > 100 m, are widespread in the surveyed areas of the Baltic Sea and are consistently formed in glacial clay. Semicircular depressions, however, are only found in a limited part of a surveyed area east of the island of Asko, southern Stockholm archipelago. While submarine terraces can be produced by several processes, we interpret our results to be in support of the basic hypothesis of terrace formation initially proposed in the 1990s; i.e. groundwater flows through siltier, more permeable layers in glacial clay to discharge at the sea floor, leading to the formation of a sharp terrace when the clay layers above seepage zones are undermined enough to collapse. By linking the terraces to a specific geologic setting, our study further refines the formation hypothesis and thereby forms the foundation for a future assessment of SGD in the Baltic Sea that may use marine geological mapping as a starting point. We propose that SGD through the submarine sea floor terraces is plausible and could be intermittent and linked to periods of higher groundwater levels, implying that to quantify the contribution of freshwater to the Baltic Sea through this potential mechanism, more complex hydrogeological studies are required.
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13.
  • Josefson, A. B., et al. (författare)
  • Burial and decomposition of plant pigments in surface sediments of the Baltic Sea: role of oxygen and benthic fauna
  • 2012
  • Ingår i: Marine Ecology-Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 455, s. 33-49
  • Tidskriftsartikel (refereegranskat)abstract
    • Degradation and burial of organic matter in sediments are important processes for oxygen dynamics and thus for the outcome of eutrophication. To assess the influences of bottom-water oxygen and macroinvertebrate fauna function on these processes, we investigated distributions of phytopigments as markers of phytoplankton detritus in surface sediments across the Baltic Sea. We compared pigment concentrations among sites with different oxygen levels and different values of a bioturbation potential index combining abundance, individual size and species-specific rankings of mobility and sediment reworking (BPI). BPI was positively influenced by oxygen availability, with a threshold at 45 to 90 mu mol l(-1), below which it decreased rapidly to zero in anoxic sediments. There was significant co-variation between pigments and both oxygen and BPI after accounting for differences in pigment concentrations with sediment depth and among different sub-areas, which were largely attributed to different inputs of phytoplankton. Negative correlations between pigments and both BPI and oxygen in communities dominated by Macoma balthica and Scoloplos armiger, and between pigments and BPI in the upper sediment layers inhabited by Monoporeia affinis and Pontoporeia femorata, suggested increased degradation with increasing bioturbation. Positive correlations between pigments and BPI in communities dominated by Marenzelleria spp. suggested mainly burial, which also was supported by positive correlations between Marenzelleria abundance and both sediment water content and the freshness of buried organic material. It is hypothesised that a shift from sensitive resident species like Monoporeia or Scoloplos to the more hypoxia-tolerant Marenzelleria will slow down overall degradation rates, counteracting hypoxia formation in the bottom water. ELEOESCHGER D, 1991, MARINE ECOLOGY-PROGRESS SERIES, V70, P83
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14.
  • Kauppi, L., et al. (författare)
  • Increasing densities of an invasive polychaete enhance bioturbation with variable effects on solute fluxes
  • 2018
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Bioturbation is a key process affecting nutrient cycling in soft sediments. The invasive polychaete genus Marenzelleria spp. has established successfully throughout the Baltic Sea increasing species and functional diversity with possible density-dependent effects on bioturbation and associated solute fluxes. We tested the effects of increasing density of M. arctia, M. viridis and M. neglecta on bioturbation and solute fluxes in a laboratory experiment. Benthic communities in intact sediment cores were manipulated by adding increasing numbers of Marenzelleria spp. The results showed that Marenzelleria spp. in general enhanced all bioturbation metrics, but the effects on solute fluxes varied depending on the solute, on the density and species identity of Marenzelleria, and on the species and functional composition of the surrounding community. M. viridis and M. neglecta were more important in predicting variation in phosphate and silicate fluxes, whereas M. arctia had a larger effect on nitrogen cycling. The complex direct and indirect pathways indicate the importance of considering the whole community and not just species in isolation in the experimental studies. Including these interactions provides a way forward regarding our understanding of the complex ecosystem effects of invasive species.
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15.
  • Kauppi, L., et al. (författare)
  • Seasonal population dynamics of the invasive polychaete genus Marenzelleria spp. in contrasting soft-sediment habitats
  • 2018
  • Ingår i: Journal of Sea Research. - : Elsevier BV. - 1385-1101 .- 1873-1414. ; 131, s. 46-60
  • Tidskriftsartikel (refereegranskat)abstract
    • Three species of the invasive polychaete genus Marenzelleria are among the dominant benthic taxa in many, especially deeper, areas in the Baltic Sea. The population dynamics of the polychaetes in the Baltic are, however, still largely unknown. We conducted monthly samplings of the benthic communities and environmental parameters at five sites with differing depths and sediment characteristics in the northern Baltic Sea (59 degrees 50.896', 23 degrees 15.092') to study the population dynamics, productivity and growth of Marenzelleria spp. from April 2013 to June 2014. The species of Marenzelleria occurring at the study sites were identified by genetic analyses. At the deepest site (33 m) only M. arctia was present, while all three species were found at the shallower, muddy sites (up to 20 m depth). At the shallow (6 m) sandy site only M. viridis and M. neglecta occurred. The sites differed in the seasonal dynamics of the Marenzelleria spp. population, reflecting the different species identities. The muddy sites up to 20 m depth showed clear seasonal dynamics, with the population practically disappearing by winter, whereas more stable populations occurred at the deepest site and at the sandy site. The highest density, biomass and production were observed at the 20 m deep, organic-rich muddy site where all three species recruited. The seasonally very high densities are likely to have important consequences for organic matter processing, and species interactions at these sites. The observed high productivity of the populations has possibly facilitated their establishment, and considerably increased secondary production in especially the deeper areas.
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16.
  • Kauppi, L., et al. (författare)
  • Seasonal variability in ecosystem functions : quantifying the contribution of invasive species to nutrient cycling in coastal ecosystems
  • 2017
  • Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 572, s. 193-207
  • Tidskriftsartikel (refereegranskat)abstract
    • Benthic ecosystems at temperate and high latitudes experience marked seasonal variation in the environmental factors affecting nutrient remineralization processes both directly and indirectly through their effects on the benthic communities. The invasive polychaete genus Marenzelleria represents new functionality in Baltic Sea sediments through its deep burrowing and extensive gallery formation, thus possibly greatly affecting benthic oxygen and nutrient fluxes. We assessed the seasonal contribution of Marenzelleria spp. to fluxes of solutes in monthly field measurements at 2 sites, 10 and 33 m deep, in the northern Baltic Proper over 1 yr. In general, the fluxes of inorganic nutrients and oxygen were higher during summer than during winter, and the seasonal variation was more pronounced at the deeper, more biologically active site. By using variation partitioning, we were able to demonstrate that Marenzelleria and other macrofauna could account for up to 92% of the variation in the fluxes depending on the site and season. Fauna was the most important in predicting the fluxes in spring when the sediment organic content and the abundance of juvenile Marenzelleria spp. were highest, while during e.g. winter, the influence of Marenzelleria spp., even though abundant, on solute fluxes was negligible. The results from this study have implications for management, and, importantly, for the modelling of nutrient budgets often based on values from studies conducted during the summer period only, thus possibly greatly miscalculating the annual nutrient fluxes.
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17.
  • Meysick, Lukas, et al. (författare)
  • Context-dependent community facilitation in seagrass meadows along a hydrodynamic stress gradient
  • 2019
  • Ingår i: Journal of Sea Research. - : Elsevier BV. - 1385-1101 .- 1873-1414. ; 150, s. 8-23
  • Tidskriftsartikel (refereegranskat)abstract
    • Foundation species host diverse associated communities by ameliorating environmental stress. The strength of this facilitative effect can be highly dependent on the underlying biotic and abiotic context. We investigated community level patterns of macrofauna associated with and adjacent to the marine foundation species eelgrass (Zostera marina) along a hydrodynamic stress gradient. We could demonstrate that the relative importance of this foundation species for its infaunal community increases with environmental variables associated with increasing hydrodynamic stress (depth, sand ripples formation, sediment grain size and organic content). Faunal assemblages in proximity to the Zostera patch edges, however, showed no (infauna) or negative (epifauna) response to hydrodynamic stress. Our study highlights that the facilitative outcome of a foundation species is conditional to the faunal assemblage in question and can be highly variable even between positions within the habitat.
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18.
  • Norkko, J., et al. (författare)
  • A welcome can of worms? Hypoxia mitigation by an invasive species
  • 2012
  • Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 18:2, s. 422-434
  • Tidskriftsartikel (refereegranskat)abstract
    • Invasive species and bottom-water hypoxia both constitute major global threats to the diversity and integrity of marine ecosystems. These stressors may interact with unexpected consequences, as invasive species that require an initial environmental disturbance to become established can subsequently become important drivers of ecological change. There is recent evidence that improved bottom-water oxygen conditions in coastal areas of the northern Baltic Sea coincide with increased abundances of the invasive polychaetes Marenzelleria spp. Using a reactive-transport model, we demonstrate that the long-term bioirrigation activities of dense Marenzelleria populations have a major impact on sedimentary phosphorus dynamics. This may facilitate the switch from a seasonally hypoxic system back to a normoxic system by reducing the potential for sediment-induced eutrophication in the upper water column. In contrast to short-term laboratory experiments, our simulations, which cover a 10-year period, show that Marenzelleria has the potential to enhance long-term phosphorus retention in muddy sediments. Over time bioirrigation leads to a substantial increase in the iron-bound phosphorus content of sediments while reducing the concentration of labile organic carbon. As surface sediments are maintained oxic, iron oxyhydroxides are able to persist and age into more refractory forms. The model illustrates mechanisms through which Marenzelleria can act as a driver of ecological change, although hypoxic disturbance or natural population declines in native species may be needed for them to initially become established. Invasive species are generally considered to have a negative impact; however, we show here that one of the main recent invaders in the Baltic Sea may provide important ecosystem services. This may be of particular importance in low-diversity systems, where disturbances may dramatically alter ecosystem services due to low functional redundancy. Thus, an environmental problem in one region may be either exacerbated or alleviated by a single species from another region, with potentially ecosystem-wide consequences.
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19.
  • Norkko, J., et al. (författare)
  • Conditional responses to increasing scales of disturbance, and potential implications for threshold dynamics in soft-sediment communities
  • 2010
  • Ingår i: Marine Ecology-Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 413, s. 253-266
  • Tidskriftsartikel (refereegranskat)abstract
    • Disturbance-recovery experiments conducted across environmental gradients can reveal the relative importance of processes, feedbacks and threshold conditions that sustain ecosystem functioning and resilience. In the present paper we argue that threshold responses to disturbance (e.g. marked non-linear shifts in abundance of important species) are scale-, context- and species-dependent. In order to test the context- dependency in recovery dynamics of soft-sediment benthic communities, we conducted a large-scale sublittoral experiment investigating patterns in recovery of 2 functionally different groups of deposit feeders (surface vs. subsurface deposit feeders; Hydrobiidae vs. Oligochaeta) with increasing spatial scales of hypoxic disturbance in the Baltic Sea. Plots (1, 4 and 16 m(2)) were defaunated at 4 sandy sites (5 m depth) that varied in exposure to wind-waves, and subsequent recovery of macrofaunal abundances was monitored over 15 mo, focusing on post-larval recolonisation. Recovery patterns were site-specific, depended on the scale of disturbance, and indicated a shift in the relative importance of smaller-scale biological factors to broader-scale physical factors, i.e. waves, currents and sediment transport, when moving from sheltered to more exposed sites. We found group-specific responses, related to mode of living (epifaunal/infaunal) and dispersal potential. In addition, Hydrobiidae exhibited opportunistic population increases in response to disturbance, likely due to increased food availability. The results highlight the importance of interactions between environmental factors, and understanding natural-history characteristics and relative mobility of different taxa, when assessing both the resilience and the recovery of benthic communities.
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20.
  • Norkko, Joanna, et al. (författare)
  • Ecosystem functioning along gradients of increasing hypoxia and changing soft-sediment community types
  • 2019
  • Ingår i: Journal of Sea Research. - : Elsevier BV. - 1385-1101 .- 1873-1414. ; 153
  • Tidskriftsartikel (refereegranskat)abstract
    • Marine ecosystems world-wide are threatened by oxygen deficiency, with potential serious consequences for ecosystem functioning and the goods and services they provide. While the effects of hypoxia on benthic species diversity are well documented, the effects on ecosystem function have only rarely been assessed in real-world settings. To better understand the links between structural changes in macro- and meiofaunal communities, hypoxic stress and benthic ecosystem function (benthic nutrient fluxes, community metabolism), we sampled a total of 11 sites in Havstensfjord and Askeröfjord (Swedish west coast) in late summer, coinciding with the largest extent and severity of seasonal hypoxia in the area. The sites spanned oxic to anoxic bottom water, and a corresponding gradient in faunal diversity. Intact sediment cores were incubated to measure fluxes of oxygen and nutrients (NO3−, NO2−, NH4+, PO43−, SiO4) across the sediment-water interface. Sediment profile imaging (SPI) footage was obtained from all sites to assess structural elements and the bioturbation depth, and additional samples were collected to characterise sediment properties and macro- and meiofaunal community composition. Bottom-water O2 concentration was the main driver of macrofauna communities, with highest abundance and biomass, as well as variability, at the sites with intermediate O2 concentration. Meiofauna on the other hand was less sensitive to bottom-water O2 concentration. Oxygen was the main driver of nutrient fluxes too, but macrofauna as well meiofauna were also significant predictors; DistLM analyses indicated that O2 concentration, macrofaunal abundance or biomass, and meiofaunal abundance collectively explained 63%, 30% and 28% of the variation in sediment O2 consumption, NH4+flux and PO43− flux, respectively. The study provides a step towards a more realistic understanding of the link between benthic fauna and ecosystem functioning, and the influence of disturbance on this relationship, which is important for management decisions aimed at protecting the dwindling biodiversity in the coastal zones around the world.
  •  
21.
  • Rodil, Iván F., et al. (författare)
  • Estimating Respiration Rates and Secondary Production of Macrobenthic Communities Across Coastal Habitats with Contrasting Structural Biodiversity
  • 2020
  • Ingår i: Ecosystems (New York. Print). - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 23:3, s. 630-647
  • Tidskriftsartikel (refereegranskat)abstract
    • A central goal of benthic ecology is to describe the pathways and quantities of energy and material flow in seafloor communities over different spatial and temporal scales. We examined the relative macrobenthic contribution to the seafloor metabolism by estimating respiration and secondary production based on seasonal measurements of macrofauna biomass across key coastal habitats of the Baltic Sea archipelago. Then, we compared the macrofauna estimates with estimates of overall seafloor gross primary production and respiration obtained from the same habitats using the aquatic eddy covariance technique. Estimates of macrobenthic respiration rates suggest habitat-specific macrofauna contribution (%) to the overall seafloor respiration ranked as follows: blue mussel reef (44.5) > seagrass meadow (25.6) > mixed meadow (24.1) > bare sand (17.8) > Fucus-bed (11.1). In terms of secondary production (g C m(-2) y(-1)), our estimates suggest ranking of habitat value as follows: blue mussel reef (493.4) > seagrass meadow (278.5) > Fucus-bed (102.2) > mixed meadow (94.2) > bare sand (52.1). Our results suggest that approximately 12 and 10% of the overall soft-sediment metabolism translated into macrofauna respiration and secondary production, respectively. The hard-bottoms exemplified two end-points of the coastal metabolism, with the Fucus-bed as a high producer and active exporter of organic C (that is, net autotrophy), and the mussel reef as a high consumer and active recycler of organic C (that is, net heterotrophy). Using a combination of metrics of ecosystem functioning, such as respiration rates and secondary production, in combination with direct habitat-scale measurements of O-2 fluxes, our study provides a quantitative assessment of the role of macrofauna for ecosystem functioning across heterogeneous coastal seascapes.
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22.
  • Rodil, Iván F., et al. (författare)
  • Seasonal Variability in Benthic-Pelagic Coupling : Quantifying Organic Matter Inputs to the Seafloor and Benthic Macrofauna Using a Multi-Marker Approach
  • 2020
  • Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • The exchange between the water column and the seafloor is a complex process, and is particularly intensive in the shallow waters of highly productive coastal areas, where the temporal variability in the inputs of pelagic organic matter will determine many aspects of the benthic community structure. However, few studies have focused on the seasonality of inputs of organic matter to the seafloor, and on the consequent dynamics and time scales of response of benthic consumers. We conducted a 1-year study where we repeatedly sampled multiple organic compounds traditionally used as markers to study the link between the pelagic organic matter inputs and the seafloor, and the potential response of benthic macrofauna to seasonal trends in phytoplankton biomass. We simultaneously quantified the particulate organic matter in the water column, the sinking material and different seafloor compartments, and analyzed it for pigments, organic carbon and nitrogen content, C/N ratio, and stable isotopes. Seafloor sediment was also analyzed for total lipids, and the dominant macrobenthic species for isotopic signatures. Results showed a major deposition of fresh organic matter during the spring bloom followed by more degraded organic matter inputs during the late summer bloom and even lower quality of the organic matter reaching the seafloor during winter. Strong positive relationships between water column and sedimentary pigments suggest that phytoplankton was the main source of carbon to the seafloor. The isotopic signatures of the dominant macrobenthic species suggest a fast response to the organic matter inputs from the water column. However, different species responded differently to the deposition of organic matter. Macoma balthica and Marenzelleria spp. fed on more reworked and degraded sedimentary material, while Monoporeia affinis showed a shift in the feeding habits according to its life stage, with adult individuals feeding on fresher material than juveniles did. Our study highlights the seasonal variability of the benthic-pelagic coupling and the utility of a multi-marker approach to follow the temporal inputs of organic matter from the water column to the seafloor and benthic organisms.
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23.
  • Rodil, Iván F., et al. (författare)
  • Towards a sampling design for characterizing habitat-specific benthic biodiversity related to oxygen flux dynamics using Aquatic Eddy Covariance
  • 2019
  • Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The Aquatic Eddy Covariance (AEC) technique has emerged as an important method to quantify in situ seafloor metabolism over large areas of heterogeneous benthic communities, enabling cross-habitat comparisons of seafloor productivity. However, the lack of a corresponding sampling protocol to perform biodiversity comparisons across habitats is impeding a full assessment of marine ecosystem metabolism. Here, we study a range of coastal benthic habitats, from rocky-bed communities defined by either perennial macroalgae or blue mussel beds to soft-sediment communities comprised of either seagrass, patches of different macrophyte species or bare sand. We estimated that the maximum contribution to the AEC metabolic flux can be found for a seafloor area of approximately 80 m(2) with a 5 meter upstream distance of the instrument across all the habitats. We conducted a sampling approach to characterize and quantify the dominant features of biodiversity (i.e., community biomass) within the main seafloor area of maximum metabolic contribution (i.e., gross primary production and community respiration) measured by the AEC. We documented a high biomass contribution of the macroalgal Fucus vesiculosus, the seagrass Zostera marina and the macroinvertebrate Mytilus edulis to the net ecosystem metabolism of the habitats. We also documented a significant role of the bare sediments for primary productivity compared to vegetated canopies of the soft sediments. The AEC also provided insight into dynamic short-term drivers of productivity such as PAR availability and water flow velocity for the productivity estimate. We regard this study as an important step forward, setting a framework for upcoming research focusing on linking biodiversity metrics and AEC flux measurements across habitats.
  •  
24.
  • Sinkko, Hanna, et al. (författare)
  • Increasing oxygen deficiency changes rare and moderately abundant bacterial communities in coastal soft sediments
  • 2019
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • Coastal hypoxia is a major environmental problem worldwide. Hypoxia-induced changes in sediment bacterial communities harm marine ecosystems and alter biogeochemical cycles. Nevertheless, the resistance of sediment bacterial communities to hypoxic stress is unknown. We investigated changes in bacterial communities during hypoxic-anoxic disturbance by artificially inducing oxygen deficiency to the seafloor for 0, 3, 7, and 48 days, with subsequent molecular biological analyses. We further investigated relationships between bacterial communities, benthic macrofauna and nutrient effluxes across the sediment-water-interface during hypoxic-anoxic stress, considering differentially abundant operational taxonomic units (OTUs). The composition of the moderately abundant OTUs changed significantly after seven days of oxygen deficiency, while the abundant and rare OTUs first changed after 48 days. High bacterial diversity maintained the resistance of the communities during oxygen deficiency until it dropped after 48 days, likely due to anoxia-induced loss of macrofaunal diversity and bioturbation. Nutrient fluxes, especially ammonium, correlated positively with the moderate and rare OTUs, including potential sulfate reducers. Correlations may reflect bacteria-mediated nutrient effluxes that accelerate eutrophication. The study suggests that even slightly higher bottom-water oxygen concentrations, which could sustain macrofaunal bioturbation, enable bacterial communities to resist large compositional changes and decrease the harmful consequences of hypoxia in marine ecosystems.
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25.
  • Timmermann, Karen, et al. (författare)
  • Modelling macrofaunal biomass in relation to hypoxia and nutrient loading
  • 2012
  • Ingår i: Journal of Marine Systems. - : Elsevier BV. - 0924-7963 .- 1879-1573. ; 105-108, s. 60-69
  • Tidskriftsartikel (refereegranskat)abstract
    • Nutrient loading of aquatic ecosystems results in more food for benthic macrofaunal communities but also increases the risk of hypoxia, resulting in a reduction or complete loss of benthic biomass. This study investigates the interaction between eutrophication, hypoxia and benthic biomass with emphasis on the balance between gains and loss of benthic biomass due to changes in nutrient loadings. A physiological fauna model with 5 functional groups was linked to a 3D coupled hydrodynamic-ecological Baltic Sea model. Model results revealed that benthic biomass increased between 0 and 700% after re-oxygenating bottom waters. Nutrient reduction scenarios indicated improved oxygen concentrations in bottom waters and decreased sedimentation of organic matter up to 40% after a nutrient load reduction following the Baltic Sea Action Plan. The lower food supply to benthos reduced the macrofaunal biomass up to 35% especially in areas not currently affected by hypoxia, whereas benthic biomass increased up to 200% in areas affected by eutrophication-induced hypoxia. The expected changes in benthic biomass resulting from nutrient load reductions and subsequent reduced hypoxia may not only increase the food supply for benthivorous fish, but also significantly affect the biogeochemical functioning of the ecosystem.
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26.
  • Valanko, S., et al. (författare)
  • Rates of post-larval bedload dispersal in a non-tidal soft-sediment system
  • 2010
  • Ingår i: Marine Ecology-Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 416, s. 145-163
  • Tidskriftsartikel (refereegranskat)abstract
    • Quantifying rates of dispersal and understanding patterns of colonization are key for predicting disturbance-recovery dynamics. For soft-sediment benthic communities recruitment is not restricted to one single event, but can be highly variable on several spatial and temporal scales. To investigate the temporal persistence of post-larval bedload transport in a non-tidal system, field experiments were conducted at 4 sites (5 m depth) across a wind-wave exposure gradient over 2 summers. Results indicate that bedload dispersal is temporally variable and dependent on an interaction between species-specific characteristics (including seasonal peaks in reproduction), site-specific hydrographic conditions, grain size characteristics and transport of sediments and drift algae. Dispersal of more passive taxa (Ostracoda, juvenile gastropods, Macoma balthica) was found to be associated with higher rates of sediment and algal transport, while more active species (Hydrobia ulvae and Potamopyrgus antipodarum) dispersed relatively more at sheltered sites. At higher rates of sediment transport, there was an increase in the proportion of larger M. balthica individuals dispersing, in contrast to Hydrobiidae, which had an increased proportion of smaller individuals. Our study suggests that frequent post-larval dispersal plays a central role in the population dynamics of many benthic invertebrates, in non-tidal systems. While the distribution of species is heavily influenced by peaked larval recruitment over large spatial scales, the net result of continuous small-scale dispersal events is clearly important and may contribute to the resilience of benthic communities.
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27.
  • Virta, Leena, et al. (författare)
  • The diversity of benthic diatoms affects ecosystem productivity in heterogeneous coastal environments
  • 2019
  • Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 100:9
  • Tidskriftsartikel (refereegranskat)abstract
    • The current decrease in biodiversity affects all ecosystems, and the impacts of diversity on ecosystem functioning need to be resolved. So far, marine studies about diversity-ecosystem productivity-relationships have concentrated on small-scale, controlled experiments, with often limited relevance to natural ecosystems. Here, we provide a real-world study on the effects of microorganismal diversity (measured as the diversity of benthic diatom communities) on ecosystem productivity (using chlorophyll a concentration as a surrogate) in a heterogeneous marine coastal archipelago. We collected 78 sediment cores at 17 sites in the northern Baltic Sea and found exceptionally high diatom diversity (328 observed species). We used structural equation models and quantile regression to explore relationships between diatom diversity and productivity. Previous studies have found contradictory results in the relationship between microorganismal diversity and ecosystem productivity, but we showed a linear and positive basal relationship between diatom diversity and productivity, which indicates that diatom diversity most likely forms the lowest boundary for productivity. Thus, although productivity can be high even when diatom diversity is low, high diatom diversity supports high productivity. The trait composition was more effective than taxonomical composition in showing such a relationship, which could be due to niche complementarity. Our results also indicated that environmental heterogeneity leads to substantial patchiness in the diversity of benthic diatom communities, mainly induced by the variation in sediment organic matter content. Therefore, future changes in precipitation and river runoff and associated changes in the quality and quantity of organic matter in the sea, will also affect diatom communities and, hence, ecosystem productivity. Our study suggests that benthic microorganisms are vital for ecosystem productivity, and together with the substantial heterogeneity of coastal ecosystems, they should be considered when evaluating the potential productivity of coastal areas.
  •  
28.
  • Andersen, JH, et al. (författare)
  • Getting the measure of eutrophication in the Baltic Sea: towards improved assessment principles and methods
  • 2011
  • Ingår i: Biogeochemistry. - 0168-2563. ; 106:2, s. 137-156
  • Tidskriftsartikel (refereegranskat)abstract
    • The eutrophication status of the entire Baltic Sea is classified using a multi-metric indicator-based assessment tool. A total of 189 areas are assessed using indicators where information on reference conditions (RefCon), and acceptable deviation (AcDev) from reference condition could be combined with national monitoring data from the period 2001–2006. Most areas (176) are classified as ‘affected by eutrophication’ and only two open water areas and 11 coastal areas are classified as ‘unaffected by eutrophication’. The classification is made by application of the recently developed HELCOM Eutrophication Assessment Tool (HEAT), which is described in this paper. The use of harmonized assessment principles and the HEAT tool allows for direct comparisons between different parts of the Baltic Sea despite variations in monitoring activities. The impaired status of 176 areas is directly related to nutrient enrichment and elevated loads from upstream catchments. Baltic Sea States have implemented nutrient management strategies since years which have reduced nutrient inputs. However, eutrophication is still a major problem for large parts of the Baltic Sea. The 2007 Baltic Sea Action Plan is projected to further reduce nutrient inputs aiming for a Baltic Sea unaffected by eutrophication by 2021.
  •  
29.
  • Angove, Charlotte, et al. (författare)
  • Assessing the efficiencies and challenges for nutrient uptake by aquatic plants
  • 2018
  • Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981 .- 1879-1697. ; 507, s. 23-30
  • Tidskriftsartikel (refereegranskat)abstract
    • Aquatic plant meadows are valuable components to the 'coastal filter' and it is important to understand the processes that drive their ability to cycle nutrients. However, at present, the field-based evidence for understanding the drivers of nutrient uptake by plants is lacking. This study aimed to investigate how well individual shoots of aquatic plants could meet their nitrogen demands using the sediment nutrient pool (porewater ammonium) and to explore which traits helped to facilitate such uptake. Several species were investigated in shallow, submerged (2-4 m) mixed-species communities in the northern Baltic Sea using incubation experiments with enriched ammonium. After a 3.5 h incubation time, individuals were collected and analysed for nitrogen (% DW) and N-15 (at-%) concentrations. Uptake by plants was calculated per unit nitrogen in response to the N-15 labelled source and to overall nitrogen availability. Background porewater ammonium availability was highly variable between individual plants. Species identity did not significantly affect uptake metrics and the effect of ambient porewater availability was weak. As biomass increased there were significant logarithmic declines in the 95th quantiles of nutrient uptake rates, ambient porewater nutrient availability and aboveground nitrogen tissue concentrations (% DW). Such findings suggested that uptake rates of plants were significantly demand driven and the nutrient conditions of the porewater were significantly driven by the demands of the plant. Findings parameterised the unfulfilled potential for some aquatic plants to cycle nutrients more efficiently and highlighted the potential importance of access to new nutrient sources as a way of enhancing nutrient cycling by aquatic plants. Plant traits and community properties such as the activity of infauna could facilitate such an access and are likely important for nutrient uptake.
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30.
  • Angove, Charlotte, et al. (författare)
  • The Fight to Capture Light : Functional Diversity Is Related to Aquatic Plant Community Productivity Likely by Enhancing Light Capture
  • 2020
  • Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Functional diversity (FD) experiments are highly effective for investigating how a community interacts with its environment. However, such experiments using morphological and chemical traits have not been conducted for submerged aquatic plants and their insights would be highly valuable for understanding the ecology of these communities. We conducted a 15-week field experiment in the Baltic Sea where we manipulated the species composition of aquatic plant communities to investigate functional diversity. We constructed artificial triculture communities with different species compositions to change the Community Weighted Means (CWMs) and variability of traits. We measured nine plant traits and tested how community productivity (CP) was related to FD, trait CWMs and community trait ranges. CP varied by more than four times across treatments and functional richness was significantly related to CP. Functional evenness and functional divergence were not significantly related to CR Height, leaf area and delta C-13 were significantly related to CP. Leaf delta C-13 trends with CP suggested that the carbon supply is not replete, yet species composition was partly responsible for the relationship. Plant height likely had multifaceted benefits to CP because there was evidence of a competitive height interaction between the tallest and 2 nd tallest species, therefore the effects of plant height to CP would have been disproportionally large. The height of the tallest species significantly drove the variability of the community height range, which was significantly related to CP and it had a relatively large influence on the calculation of FD indices. Leaf area, which was strongly correlated to plant height, was also significantly related to CR The significant relationship between functional richness and CP was most likely driven by the presence of taller plants. FD likely enhanced CP, by selecting for extreme trait values which enhanced production (selection effect), while niche complementarity effects were not observed. This study provides experimental evidence and mechanistic insights into the role of FD and specific traits for CP in submerged aquatic plant communities. To conclude, FD was significantly related to CP of temperate aquatic plant communities likely by selecting for traits which enhanced light capture, with consequences for carbon supply.
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31.
  • Asmala, Eero, et al. (författare)
  • Role of Eelgrass in the Coastal Filter of Contrasting Baltic Sea Environments
  • 2019
  • Ingår i: Estuaries and Coasts. - : Springer Science and Business Media LLC. - 1559-2723 .- 1559-2731. ; 42:7, s. 1882-1895
  • Tidskriftsartikel (refereegranskat)abstract
    • Coastal ecosystems act as filters of nutrients from land to the open sea. We investigated the role of eelgrass (Zostera marina) metabolism in the coastal filter transforming nitrogen, phosphorus, and organic carbon. Field campaigns following identical methodologies were carried out at two contrasting coastal locations: the mesohaline and nutrient-rich Roskilde Fjord, Denmark, and the mesotrophic brackish Tvarminne archipelago, Finland. Over the 24-h in situ benthic incubations, we measured oxygen concentrations continuously and assessed changes in DOM characteristics and net fluxes of carbon, nitrogen, and phosphorus. Ecosystem metabolism modeled on the basis of the O-2 data showed that the systems were either net heterotrophic (Roskilde Fjord; - 1.6 and - 2.4 g O-2 m(-2) day(-1) in eelgrass meadow and bare sand, respectively) or had balanced primary production and respiration (Tvarminne; 0.0 and 0.2 g O-2 m(-2) day(-1)). Overall, initial nutrient stoichiometry was a key factor determining benthic-pelagic fluxes of nutrients, which exacerbated the deviations from Redfield ratios of N and P, indicating an efficient use of the limiting nutrient. A net diel uptake of dissolved inorganic N was observed at both locations (- 2.3 mu mol l(-1) day(-1) in Roskilde Fjord and - 0.1 mu mol l(-1) day(-1) in Tvarminne). Despite minor changes in dissolved organic carbon concentrations during the incubations, a marked increase of fluorescent DOM was observed at both locations, suggesting rapid heterotrophic processing of the DOM pool. Our results underline that the biogeochemical role of eelgrass in the coastal filter is not inherent, but strongly dependent on the environmental conditions.
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32.
  • Attard, Karl M., et al. (författare)
  • Metabolism of a subtidal rocky mussel reef in a high-temperate setting : pathways of organic C flow
  • 2020
  • Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 645, s. 41-54
  • Tidskriftsartikel (refereegranskat)abstract
    • Mytilid mussels form abundant, species-rich reefs on rocky substrates, but the role of this key habitat in carbon (C) cycling remains poorly understood. We performed a seasonal study on a 5 m deep photic Mytilus trossulus reef in the Central Baltic Sea to investigate pathways and rates of organic C flow. Reef gross primary production (GPP) and respiration (R) were estimated seasonally using underwater O2 eddy covariance on hourly and daily timescales. Photogrammetry and biotic sampling were used to quantify reef rugosity and mussel coverage, and to derive mussel filtration and biodeposition. Mussels were highly abundant, reaching ~50000 ind. m-2, and the reef structure increased the seabed surface area by 44%. GPPhourly was up to 20 mmol O2 m-2 h-1 and GPPdaily was up to 107 mmol O2 m-2 d-1, comparable to a nearby seagrass canopy. Hourly eddy fluxes responded linearly to light intensity and flow velocity, with higher velocities enhancing reef O2 uptake at night. Reef Rdaily exceeded GPPdaily on 12 of 13 measurement days, and Rannual (29 mol O2 m-2 yr-1) was 3-fold larger than GPPannual. The reef sustained a productive community of microbes and fauna whose activities accounted for ~50% of Rannual. Horizontal water advection promoted food supply to the reef and likely facilitated substantial lateral C export of mussel biodeposits. Our analyses suggest that a reduction in mussel reef extent due to ongoing environmental change will have major implications for the transport and transformation of C and nutrients within the coastal Baltic Sea.
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33.
  • Broman, Elias, 1985-, et al. (författare)
  • Biotic interactions between benthic infauna and aerobic methanotrophs mediate methane fluxes from coastal sediments
  • 2024
  • Ingår i: The ISME journal. - 1751-7370 .- 1751-7362. ; 18:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Coastal ecosystems dominate oceanic methane (CH4) emissions. However, there is limited knowledge about how biotic interactions between infauna and aerobic methanotrophs (i.e. CH4 oxidizing bacteria) drive the spatial-temporal dynamics of these emissions. Here, we investigated the role of meio- and macrofauna in mediating CH4 sediment-water fluxes and aerobic methanotrophic activity that can oxidize significant portions of CH4. We show that macrofauna increases CH4 fluxes by enhancing vertical solute transport through bioturbation, but this effect is somewhat offset by high meiofauna abundance. The increase in CH4 flux reduces CH4 pore-water availability, resulting in lower abundance and activity of aerobic methanotrophs, an effect that counterbalances the potential stimulation of these bacteria by higher oxygen flux to the sediment via bioturbation. These findings indicate that a larger than previously thought portion of CH4 emissions from coastal ecosystems is due to faunal activity and multiple complex interactions with methanotrophs.
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34.
  • Broman, Elias, et al. (författare)
  • High throughput shotgun sequencing of eRNA reveals taxonomic and derived functional shifts across a benthic productivity gradient
  • 2021
  • Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 30:13, s. 3023-39
  • Tidskriftsartikel (refereegranskat)abstract
    • © 2020 The Authors. Molecular Ecology published by John Wiley & Sons Ltd Benthic macrofauna is regularly used in monitoring programmes, however the vast majority of benthic eukaryotic biodiversity lies mostly in microscopic organisms, such as meiofauna (invertebrates<1mm) and protists, that rapidly responds to environmental change. These communities have traditionally been hard to sample and handle in the laboratory, but DNA sequencing has made such work less time consuming. While DNA sequencing captures both alive and dead organisms, environmental RNA (eRNA) better targets living organisms or organisms of recent origin in the environment. Here, we assessed the biodiversity of three known bioindicator microeukaryote groups (nematodes, foraminifera, and ciliates) in sediment samples collected at seven coastal sites along an organic carbon (OC) gradient. We aimed to investigate if eRNA shotgun sequencing can be used to simultaneously detect differences in (i) biodiversity of multiple microeukaryotic communities; and (ii) functional feeding traits of nematodes. Results showed that biodiversity was lower for nematodes and foraminifera in high OC (6.2%–6.9%), when compared to low OC sediments (1.2%–2.8%). Dissimilarity in community composition increased for all three groups between Low OC and High OC, as well as the classified feeding type of nematode genera (with more nonselective deposit feeders in high OC sediment). High relative abundant genera included nematode Sabatieria and foraminifera Elphidium in high OC, and Cryptocaryon-like ciliates in low OC sediments. Considering that future sequencing technologies are likely to decrease in cost, the use of eRNA shotgun sequencing to assess biodiversity of benthic microeukaryotes could be a powerful tool in recurring monitoring programmes.
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35.
  • Broman, Elias, et al. (författare)
  • Low Abundance of Methanotrophs in Sediments of Shallow Boreal Coastal Zones With High Water Methane Concentrations
  • 2020
  • Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 11
  • Tidskriftsartikel (refereegranskat)abstract
    • Coastal zones are transitional areas between land and sea where large amounts of organic and inorganic carbon compounds are recycled by microbes. Especially shallow zones near land have been shown to be the main source for oceanic methane (CH4) emissions. Water depth has been predicted as the best explanatory variable, which is related to CH4 ebullition, but exactly how sediment methanotrophs mediates these emissions along water depth is unknown. Here, we investigated the relative abundance and RNA transcripts attributed to methane oxidation proteins of aerobic methanotrophs in the sediment of shallow coastal zones with high CH4 concentrations within a depth gradient from 10–45 m. Field sampling consisted of collecting sediment (top 0–2 cm layer) from eight stations along this depth gradient in the coastal Baltic Sea. The relative abundance and RNA transcripts attributed to the CH4 oxidizing protein (pMMO; particulate methane monooxygenase) of the dominant methanotroph Methylococcales was significantly higher in deeper costal offshore areas (36–45 m water depth) compared to adjacent shallow zones (10–28 m). This was in accordance with the shallow zones having higher CH4 concentrations in the surface water, as well as more CH4 seeps from the sediment. Furthermore, our findings indicate that the low prevalence of Methylococcales and RNA transcripts attributed to pMMO was restrained to the euphotic zone (indicated by Photosynthetically active radiation (PAR) data, photosynthesis proteins, and 18S rRNA data of benthic diatoms). This was also indicated by a positive relationship between water depth and the relative abundance of Methylococcales and pMMO. How these processes are affected by light availability requires further studies. CH4 ebullition potentially bypasses aerobic methanotrophs in shallow coastal areas, reducing CH4 availability and limiting their growth. Such mechanism could help explain their reduced relative abundance and related RNA transcripts for pMMO. These findings can partly explain the difference in CH4 concentrations between shallow and deep coastal areas, and the relationship between CH4 concentrations and water depth.
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36.
  • Broman, Elias, 1985-, et al. (författare)
  • No evidence of light inhibition on aerobic methanotrophs in coastal sediments using eDNA and eRNA
  • 2023
  • Ingår i: Environmental DNA. - 2637-4943. ; 5:4, s. 766-781
  • Tidskriftsartikel (refereegranskat)abstract
    • It is estimated that up to half of global methane (CH4) emissions are derived from microbial processes in aquatic ecosystems. However, it is not fully understood which factors explain the spatial and temporal variability of these emissions. For example, light has previously been shown to both inhibit and stimulate aerobic methane-oxidizing bacteria (i.e., methanotrophs) in the water column. These contrasting results indicate that the mechanisms that light has on CH4 oxidation are not yet clearly known, even less so for benthic aerobic methanotrophs. Here, we tested whether light reaching the seafloor can inhibit methanotrophic activity on the sediment surface. We sampled and distributed over 40 intact sediment cores from two coastal sites (illuminated 10 m, and a dark site at 33 m water depth) into 0, 50, and 100 PAR light treatments. After 10 days, we found no difference between treatments for each site in pore-water CH4 concentrations, relative abundance of aerobic methanotrophs, or the number of RNA transcripts related to methane oxidation. Our results suggest that light attenuation in coastal waters does not significantly affect aerobic methanotrophs in coastal sediments.
  •  
37.
  • Carstensen, Jacob, et al. (författare)
  • Factors regulating the coastal nutrient filter in the Baltic Sea
  • 2020
  • Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 49:6, s. 1194-1210
  • Tidskriftsartikel (refereegranskat)abstract
    • The coastal zone of the Baltic Sea is diverse with strong regional differences in the physico-chemical setting. This diversity is also reflected in the importance of different biogeochemical processes altering nutrient and organic matter fluxes on the passage from land to sea. This review investigates the most important processes for removal of nutrients and organic matter, and the factors that regulate the efficiency of the coastal filter. Nitrogen removal through denitrification is high in lagoons receiving large inputs of nitrate and organic matter. Phosphorus burial is high in archipelagos with substantial sedimentation, but the stability of different burial forms varies across the Baltic Sea. Organic matter processes are tightly linked to the nitrogen and phosphorus cycles. Moreover, these processes are strongly modulated depending on composition of vegetation and fauna. Managing coastal ecosystems to improve the effectiveness of the coastal filter can reduce eutrophication in the open Baltic Sea.
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38.
  • Conley, Daniel, et al. (författare)
  • Hypoxia-Related Processes in the Baltic Sea
  • 2009
  • Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:10, s. 3412-3420
  • Tidskriftsartikel (refereegranskat)abstract
    • Hypoxia, a growing worldwide problem, has been intermittently present in the modern Baltic Sea since its formation ca. 8000 cal. yr BP. However, both the spatial extent and intensity of hypoxia have increased with anthropogenic eutrophication due to nutrient inputs. Physical processes, which control stratification and the renewal of oxygen in bottom waters, are important constraints on the formation and maintenance of hypoxia. Climate controlled inflows of saline water from the North Sea through the Danish Straits is a critical controlling factor governing the spatial extent and duration of hypoxia. Hypoxia regulates the biogeochemical cycles of both phosphorus (P) and nitrogen (N) in the water column and sediments. Significant amounts of P are currently released from sediments, an order of magnitude larger than anthropogenic inputs. The Baltic Sea is unique for coastal marine ecosystems experiencing N losses in hypoxic waters below the halocline. Although benthic communities in the Baltic Sea are naturally constrained by salinity gradients, hypoxia has resulted in habitat loss over vast areas and the elimination of benthic fauna, and has severely disrupted benthic food webs. Nutrient load reductions are needed to reduce the extent, severity, and effects of hypoxia.
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39.
  •  
40.
  • Cummings, Vonda J., et al. (författare)
  • Linking Ross Sea Coastal Benthic Communities to Environmental Conditions : Documenting Baselines in a Spatially Variable and Changing World
  • 2018
  • Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 5
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding the functionality of marine benthic ecosystems, and how they are influenced by their physical environment, is fundamental to realistically predicting effects of future environmental change. The Antarctic faces multiple environmental pressures associated with greenhouse gas emissions, emphasizing the need for baseline information on biodiversity and the bio-physical processes that influence biodiversity. We describe a survey of shallow water benthic communities at eight Ross Sea locations with a range of environmental characteristics. Our analyses link coastal benthic community composition to seafloor habitat and sedimentary parameters and broader scale features, at locations encompassing considerable spatial extent and variation in environmental characteristics (e.g., seafloor habitat, sea ice conditions, hydrodynamic regime, light). Our aims were to: (i) document existing benthic communities, habitats and environmental conditions against which to assess future change, (ii) investigate the relationships between environmental and habitat characteristics and benthic community structure and function, and (iii) determine whether these relationships were dependent on spatial extent. A very high percentage (>95%) of the between-location variability in macro- or epifaunal community composition was explainable using multi-scale environmental variables. The explanatory power varied depending on the scale of influence of the environmental variables measured (fine and medium-scale habitat, broad scale), and with community type. However, the inclusion of parameters at all scales produced the most powerful model for both communities. Ice duration, ice thickness and snow cover were important broad scale variables identified that directly relate to climate change. Even when using only habitat-scale variables, extending the spatial scale of the study from three locations covering 32 km to eight locations covering ~340 km increased the degree of explanatory power from 18–32 to 64–78%. The increase in explanatory power with spatial extent lends weight to the possibility of using an indirect “space for time” substitution approach for future predictions of the effects of change on these coastal marine ecosystems. Given the multiple and interacting drivers of change in Antarctic coastal ecosystems a multidisciplinary, long term, repeated observation approach will be vital to both improve and test predictions of how coastal communities will respond to environmental change.
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41.
  • Ehrnsten, Eva, et al. (författare)
  • Benthic-pelagic coupling in coastal seas - Modelling macrofaunal biomass and carbon processing in response to organic matter supply
  • 2019
  • Ingår i: Journal of Marine Systems. - : Elsevier BV. - 0924-7963 .- 1879-1573. ; 196, s. 36-47
  • Tidskriftsartikel (refereegranskat)abstract
    • Benthic macrofauna is an important component linking pelagic and benthic ecosystems, especially in productive coastal areas. Through their metabolism and behaviour, benthic animals affect biogeochemical fluxes between the sediment and water column. Mechanistic models that quantify these benthic-pelagic links are imperative to understand the functioning of coastal ecosystems. In this study, we develop a dynamic model of benthic macrofauna to quantify the relationship between organic matter input and benthic macrofaunal biomass in the coastal zone. The model simulates the carbon dynamics of three functional groups of benthic macrofauna and their sediment food sources and is forced by a hydrodynamic-biogeochemical model simulating pelagic physical and biological dynamics. The model reproduces measured time-series of macrofaunal biomass from two coastal sites with contrasting sedimentation in the Baltic Sea in 1993-2005 with comparatively high accuracy, including a major increase at one of the sites dominated by the bivalve Limecola (Macoma) balthica. This shift in community composition suggests altered pathways of organic matter degradation: 39% of simulated sedimentation was mineralised by macrofauna in 2005 compared to 10% in 1995. From the early 2000s onward macrofaunal biomass seems to be food-limited, as ca 80% of organic carbon sedimentation was processed by the deposit-feeding macrofauna at both sites. This model is a first step to help quantify the role of macrofauna in marine coastal ecosystem functioning and biogeochemical cycles and build predictive capacity of the effects of anthropogenic stressors, such as eutrophication and climate change, on coastal ecosystems.
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42.
  • Ehrnsten, Eva, et al. (författare)
  • The meagre future of benthic fauna in a coastal sea-Benthic responses to recovery from eutrophication in a changing climate
  • 2020
  • Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:4, s. 2235-2250
  • Tidskriftsartikel (refereegranskat)abstract
    • Nutrient loading and climate change affect coastal ecosystems worldwide. Unravelling the combined effects of these pressures on benthic macrofauna is essential for understanding the future functioning of coastal ecosystems, as it is an important component linking the benthic and pelagic realms. In this study, we extended an existing model of benthic macrofauna coupled with a physical-biogeochemical model of the Baltic Sea to study the combined effects of changing nutrient loads and climate on biomass and metabolism of benthic macrofauna historically and in scenarios for the future. Based on a statistical comparison with a large validation dataset of measured biomasses, the model showed good or reasonable performance across the different basins and depth strata in the model area. In scenarios with decreasing nutrient loads according to the Baltic Sea Action Plan but also with continued recent loads (mean loads 2012-2014), overall macrofaunal biomass and carbon processing were projected to decrease significantly by the end of the century despite improved oxygen conditions at the seafloor. Climate change led to intensified pelagic recycling of primary production and reduced export of particulate organic carbon to the seafloor with negative effects on macrofaunal biomass. In the high nutrient load scenario, representing the highest recorded historical loads, climate change counteracted the effects of increased productivity leading to a hyperbolic response: biomass and carbon processing increased up to mid-21st century but then decreased, giving almost no net change by the end of the 21st century compared to present. The study shows that benthic responses to environmental change are nonlinear and partly decoupled from pelagic responses and indicates that benthic-pelagic coupling might be weaker in a warmer and less eutrophic sea.
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43.
  • Ehrnsten, Eva, et al. (författare)
  • Understanding Environmental Changes in Temperate Coastal Seas : Linking Models of Benthic Fauna to Carbon and Nutrient Fluxes
  • 2020
  • Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 7
  • Forskningsöversikt (refereegranskat)abstract
    • Coastal seas are highly productive systems, providing an array of ecosystem services to humankind, such as processing of nutrient effluents from land and climate regulation. However, coastal ecosystems are threatened by human-induced pressures such as climate change and eutrophication. In the coastal zone, the fluxes and transformations of nutrients and carbon sustaining coastal ecosystem functions and services are strongly regulated by benthic biological and chemical processes. Thus, to understand and quantify how coastal ecosystems respond to environmental change, mechanistic modeling of benthic biogeochemical processes is required. Here, we discuss the present model capabilities to quantitatively describe how benthic fauna drives nutrient and carbon processing in the coastal zone. There are a multitude of modeling approaches of different complexity, but a thorough mechanistic description of benthic-pelagic processes is still hampered by a fundamental lack of scientific understanding of the diverse interactions between the physical, chemical and biological processes that drive biogeochemical fluxes in the coastal zone. Especially shallow systems with long water residence times are sensitive to the activities of benthic organisms. Hence, including and improving the description of benthic biomass and metabolism in sediment diagenetic as well as ecosystem models for such systems is essential to increase our understanding of their response to environmental changes and the role of coastal sediments in nutrient and carbon cycling. Major challenges and research priorities are (1) to couple the dynamics of zoobenthic biomass and metabolism to sediment reactive-transport in models, (2) to test and validate model formulations against real-world data to better incorporate the context-dependency of processes in heterogeneous coastal areas in models and (3) to capture the role of stochastic events.
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44.
  • Gibbs, M., et al. (författare)
  • Benthic nutrient fluxes along an estuarine gradient: influence of the pinnid bivalve Atrina zelandica in summer
  • 2005
  • Ingår i: Marine Ecology-Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 288, s. 151-164
  • Tidskriftsartikel (refereegranskat)abstract
    • Benthic nutrient fluxes (BNF) can supply 30 to 100% of the nutrient requirements of benthic and pelagic algae in an estuary, and can, thus, potentially sustain benthic and pelagic primary production within the estuarine food web. While BNF can be influenced by microbial processes, epibenthic suspension-feeding bivalves have the potential to alter fluxes by their influence on the community composition of surrounding macrofauna and benthic boundary conditions, and their feeding activities. In Mahurangi Harbour, New Zealand, the large suspension feeding pinnid Atrina zelandica (hereafter referred to as Atrina) occupies large areas of the harbour floor. Consequently, Atrina have the potential to substantially influence the BNF and, thus, primary production, and the food supply to the filter feeding community within the harbour, including the rack-farmed Pacific oyster aquaculture industry. Mahurangi Harbour is almost always isohaline, but exhibits a strong gradient in suspended sediment concentration, which declines from head to mouth. As Atrina increase their rate of pseudofaeces production with increases in suspended sediment concentration, we conducted in situ light and dark paired benthic chamber experiments with and without Atrina at 4 stations along this turbidity gradient, to determine their effect on BNF. Our results showed substantially greater BNF from Atrina beds than bare sediments. We also found greater net BNF (difference between Atrina beds and bare sediment) in the less turbid water under dark conditions, but enhanced water column nutrient supply in the more turbid water in light, due to Atrina excretion of ammoniacal nitrogen (NH4-N). On an areal basis, we estimate that BNF from Atrina beds may account for up to 80% of the nutrient supply for pelagic primary production and, thus, they are of major importance to the sustainability of aquaculture in this harbour.
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45.
  • Gladstone-Gallagher, Rebecca V., et al. (författare)
  • Identifying “vital attributes” for assessing disturbance–recovery potential of seafloor communities
  • 2021
  • Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 11:11, s. 6091-6103
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite a long history of disturbance-recovery research, we still lack a generalizable understanding of the attributes that drive community recovery potential in seafloor ecosystems. Marine soft-sediment ecosystems encompass a range of heterogeneity from simple low-diversity habitats with limited biogenic structure, to species-rich systems with complex biogenic habitat structure. These differences in biological heterogeneity are a product of natural conditions and disturbance regimes. To search for unifying attributes, we explore whether a set of simple traits can characterize community disturbance-recovery potential using seafloor patch-disturbance experiments conducted in two different soft-sediment landscapes. The two landscapes represent two ends of a spectrum of landscape biotic heterogeneity in order to consider multi-scale disturbance-recovery processes. We consider traits at different levels of biological organization, from the biological traits of individual species, to the traits of species at the landscape scale associated with their occurrence across the landscape and their ability to be dominant. We show that in a biotically heterogeneous landscape (Kawau Bay, New Zealand), seafloor community recovery is stochastic, there is high species turnover, and the landscape-scale traits are good predictors of recovery. In contrast, in a biotically homogeneous landscape (Baltic Sea), the options for recovery are constrained, the recovery pathway is thus more deterministic and the scale of recovery traits important for determining recovery switches to the individual species biological traits within the disturbed patch. Our results imply that these simple, yet sophisticated, traits can be effectively used to characterize community recovery potential and highlight the role of landscapes in providing resilience to patch-scale disturbances.
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46.
  • Gladstone-Gallagher, Rebecca V., et al. (författare)
  • Social-ecological connections across land, water, and sea demand a reprioritization of environmental management
  • 2022
  • Ingår i: Elementa. - : University of California Press. - 2325-1026. ; 10:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite many sectors of society striving for sustainability in environmental management, humans often fail to identify and act on the connections and processes responsible for social–ecological tipping points. Part of the problem is the fracturing of environmental management and social–ecological research into ecosystem domains (land, freshwater, and sea), each with different scales and resolution of data acquisition and distinct management approaches. We present a perspective on the social–ecological connections across ecosystem domains that emphasize the need for management reprioritization to effectively connect these domains. We identify critical nexus points related to the drivers of tipping points, scales of governance, and the spatial and temporal dimensions of social–ecological processes. We combine real-world examples and a simple dynamic model to illustrate the implications of slow management responses to environmental impacts that traverse ecosystem domains. We end with guidance on management and research opportunities that arise from this cross-domain lens to foster greater opportunity to achieve environmental and sustainability goals.
  •  
47.
  • Graco-Roza, Caio, et al. (författare)
  • Distance decay 2.0 – A global synthesis of taxonomic and functional turnover in ecological communities
  • 2022
  • Ingår i: Global Ecology and Biogeography. - : Wiley. - 1466-822X .- 1466-8238. ; 31:7, s. 1399-1421
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim: Understanding the variation in community composition and species abundances (i.e., beta-diversity) is at the heart of community ecology. A common approach to examine beta-diversity is to evaluate directional variation in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distance. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 148 datasets comprising different types of organisms and environments.Location: Global.Time period: 1990 to present.Major taxa studied: From diatoms to mammals.Method: We measured the strength of the decay using ranked Mantel tests (Mantel r) and the rate of distance decay as the slope of an exponential fit using generalized linear models. We used null models to test whether functional similarity decays faster or slower than expected given the taxonomic decay along the spatial and environmental distance. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm and organismal features.Results: Taxonomic distance decay was stronger than functional distance decay along both spatial and environmental distance. Functional distance decay was random given the taxonomic distance decay. The rate of taxonomic and functional spatial distance decay was fastest in the datasets from mid-latitudes. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distance but a higher rate of decay along environmental distance. Marine ecosystems had the slowest rate of decay along environmental distances.Main conclusions: In general, taxonomic distance decay is a useful tool for biogeographical research because it reflects dispersal-related factors in addition to species responses to climatic and environmental variables. Moreover, functional distance decay might be a cost-effective option for investigating community changes in heterogeneous environments.
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48.
  • Griffiths, Jennifer R., et al. (författare)
  • The importance of benthic-pelagic coupling for marine ecosystem functioning in a changing world
  • 2017
  • Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 23:6, s. 2179-2196
  • Forskningsöversikt (refereegranskat)abstract
    • Benthic-pelagic coupling is manifested as the exchange of energy, mass, or nutrients between benthic and pelagic habitats. It plays a prominent role in aquatic ecosystems, and it is crucial to functions from nutrient cycling to energy transfer in food webs. Coastal and estuarine ecosystem structure and function are strongly affected by anthropogenic pressures; however, there are large gaps in our understanding of the responses of inorganic nutrient and organic matter fluxes between benthic habitats and the water column. We illustrate the varied nature of physical and biological benthic-pelagic coupling processes and their potential sensitivity to three anthropogenic pressures - climate change, nutrient loading, and fishing - using the Baltic Sea as a case study and summarize current knowledge on the exchange of inorganic nutrients and organic material between habitats. Traditionally measured benthic-pelagic coupling processes (e.g., nutrient exchange and sedimentation of organic material) are to some extent quantifiable, but the magnitude and variability of biological processes are rarely assessed, preventing quantitative comparisons. Changing oxygen conditions will continue to have widespread effects on the processes that govern inorganic and organic matter exchange among habitats while climate change and nutrient load reductions may have large effects on organic matter sedimentation. Many biological processes (predation, bioturbation) are expected to be sensitive to anthropogenic drivers, but the outcomes for ecosystem function are largely unknown. We emphasize how improved empirical and experimental understanding of benthic-pelagic coupling processes and their variability are necessary to inform models that can quantify the feedbacks among processes and ecosystem responses to a changing world.
  •  
49.
  • Gustafsson, Camilla, et al. (författare)
  • Quantifying the importance of functional traits for primary production in aquatic plant communities
  • 2019
  • Ingår i: Journal of Ecology. - : Wiley. - 0022-0477 .- 1365-2745. ; 107:1, s. 154-166
  • Tidskriftsartikel (refereegranskat)abstract
    • 1. Aquatic plant meadows are important coastal habitats that sustain many ecosystem functions such as primary production and carbon sequestration. Currently, there is a knowledge gap in understanding which plant functional traits, for example, leaf size or plant height underlie primary production in aquatic plant communities.2. To study how plant traits are related to primary production, we conducted a field survey in the Baltic Sea, Finland, which is characterized by high plant species and functional diversity. Thirty sites along an exposure gradient were sampled (150 plots), and nine plant morphological and chemical traits measured. The aim was to discern how community-weighted mean traits affect community production and whether this relationship changes along an environmental gradient using structural equation modelling (SEM).3. Plant height had a direct positive effect on production along an exposure gradient (r=0.33) and indirect effects through two leaf chemical traits, leaf delta N-15 and leaf delta C-13 (r=0.24 and 0.18, respectively) resulting in a total effect of 0.28. In plant communities experiencing varying exposure, traits such as root N concentration and leaf delta N-15 had positive and negative effects on production, respectively.4. Synthesis. Our results demonstrate that the relationship between aquatic plant functional traits and community production is variable and changes over environmental gradients. Plant height generally has a positive effect on community production along an exposure gradient, while the link between other traits and production changes in plant communities experiencing varying degrees of exposure. Thus, the underlying biological mechanisms influencing production differ in plant communities, emphasizing the need to resolve variability and its drivers in real-world communities. Importantly, functionally diverse plant communities sustain ecosystem functioning differently and highlight the importance of benthic diversity for coastal ecosystem stability.
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50.
  • Hajializadeh, Parima, et al. (författare)
  • Species Composition and Functiona Traits of Macrofauna in Different Mangrove Habitats in the Persian Gulf
  • 2020
  • Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 7
  • Tidskriftsartikel (refereegranskat)abstract
    • Macrofauna play a key role in the functioning of mangrove ecosystems. Nevertheless, our understanding of the diversity and functional structure of macrofaunal communities across different habitats in the mangrove forests of the Persian Gulf is limited. In this study, we investigated species diversity and biological trait patterns of macrofauna in different mangrove-associated habitats, i.e., encompassing actual mangrove forests, and adjacent Beaches and Creeks, which exhibit different levels of habitat heterogeneity. Samples were collected from the different habitats in five different locations, over four seasons. A total of 122 macrofauna taxa were identified. The diversity of species was higher in summer than in winter. In the Beach habitats, species diversity showed an increasing trend from land toward the mangrove, whereas in Creek habitats diversity decreased from the Creek toward the mangrove. Multivariate community analysis showed differences in the distribution of abundant species and biological traits across all habitats. Deposit-feeding, crawlers, medium-size, and free-living were the dominant trait modalities in all habitats. The similarities within habitats over the four seasons had the same specific pattern of species and biological trait abundance in the Beach and the Creek, increasing from the non-covered habitat into the mangrove trees. Although many species shared similar traits, the abundance-driven differences in trait expression between habitats showed the importance of habitat filtering. The results of this study will be useful in the conservation of mangrove forests and they give a deeper understanding of the ecological patterns and functions of benthic macrofaunal communities in the Persian Gulf.
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