| 1. |
- Lind, Ulrika, et al.
(författare)
-
Analysis of aquaporins from the euryhaline barnacle Balanus improvisus reveals differential expression in response to changes in salinity
- 2017
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:7
-
Tidskriftsartikel (refereegranskat)abstract
- Barnacles are sessile macro-invertebrates, found along rocky shores in coastal areas worldwide. The euryhaline bay barnacle Balanus improvisus (Darwin, 1854) (= Amphibalanus improvisus) can tolerate a wide range of salinities, but the molecular mechanisms underlying the osmoregulatory capacity of this truly brackish species are not well understood. Aquaporins are pore-forming integral membrane proteins that facilitate transport of water, small solutes and ions through cellular membranes, and that have been shown to be important for osmoregulation in many organisms. The knowledge of the function of aquaporins in crustaceans is, however, limited and nothing is known about them in barnacles. We here present the repertoire of aquaporins from a thecostracan crustacean, the barnacle B. improvisus, based on genome and transcriptome sequencing. Our analyses reveal that B. improvisus contains eight genes for aquaporins. Phylogenetic analysis showed that they represented members of the classical water aquaporins (Aqp1, Aqp2), the aquaglyceroporins (Glp1, Glp2), the unorthodox aquaporin (Aqp12) and the arthropod-specific big brain aquaporin (Bib). Interestingly, we also found two big brain-like proteins (BibL1 and BibL2) constituting a new group of aquaporins not yet described in arthropods. In addition, we found that the two water-specific aquaporins were expressed as C-terminal splice variants. Heterologous expression of some of the aquaporins followed by functional characterization showed that Aqp1 transported water and Glp2 water and glycerol, agreeing with the predictions of substrate specificity based on 3D modeling and phylogeny. To investigate a possible role for the B. improvisus aquaporins in osmoregulation, mRNA expression changes in adult barnacles were analysed after long-term acclimation to different salinities. The most pronounced expression difference was seen for AQP1 with a substantial (>100-fold) decrease in the mantle tissue in low salinity (3 PSU) compared to high salinity (33 PSU). Our study provides a base for future mechanistic studies on the role of aquaporins in osmoregulation. © 2017 Lind et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
|
|
| 2. |
- Bausch, A. R., et al.
(författare)
-
Influence of bacteria on shell dissolution in dead gastropod larvae and adult Limacina helicina pteropods under ocean acidification conditions
- 2018
-
Ingår i: Marine Biology. - : Springer Science and Business Media LLC. - 0025-3162 .- 1432-1793. ; 165:2
-
Tidskriftsartikel (refereegranskat)abstract
- Ocean acidification (OA) increases aragonite shell dissolution in calcifying marine organisms. It has been proposed that bacteria associated with molluscan shell surfaces in situ could damage the periostracum and reduce its protective function against shell dissolution. However, the influence of bacteria on shell dissolution under OA conditions is unknown. In this study, dissolution in dead shells from gastropod larvae and adult pteropods (Limacina helicina) was examined following a 5-day incubation under a range of aragonite saturation states (Omega(arag); values ranging from 0.5 to 1.8) both with and without antibiotics. Gastropod and pteropod specimens were collected from Puget Sound, Washington (48 degrees 33'19.N, 122 degrees 59'49''W and 47 degrees 41'11''N, 122 degrees 25'23''W, respectively), preserved, stored, and then treated in August 2015. Environmental scanning electron microscopy (ESEM) was used to determine the severity and extent of dissolution, which was scored as mild, severe, or summed (mild + severe) dissolution. Shell dissolution increased with decreasing Omega(arag). In gastropod larvae, there was a significant interaction between the effects of antibiotics and Omega(arag) on severe dissolution, indicating that microbes could mediate certain types of dissolution among shells under low Omega(arag). In L. helicina, there were no significant interactions between the effects of antibiotics and Omega(arag) on dissolution. These findings suggest that bacteria may differentially influence the response of some groups of shelled planktonic gastropods to OA conditions. This is the first assessment of the microbial-chemical coupling of dissolution in shells of either gastropod larvae or adult L. helicina under OA.
|
|
| 3. |
- Britton, D., et al.
(författare)
-
Adjustments in fatty acid composition is a mechanism that can explain resilience to marine heatwaves and future ocean conditions in the habitat-forming seaweed Phyllospora comosa (Labillardiere) C.Agardh
- 2020
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:6, s. 3512-3524
-
Tidskriftsartikel (refereegranskat)abstract
- Marine heatwaves are extreme events that can have profound and lasting impacts on marine species. Field observations have shown seaweeds to be highly susceptible to marine heatwaves, but the physiological drivers of this susceptibility are poorly understood. Furthermore, the effects of marine heatwaves in conjunction with ocean warming and acidification are yet to be investigated. To address this knowledge gap, we conducted a laboratory culture experiment in which we tested the growth and physiological responses of Phyllospora comosa juveniles from the southern extent of its range (43 - 31 degrees S) to marine heatwaves, ocean warming and acidification. We used a "collapsed factorial design" in which marine heatwaves were superimposed on current (today's pH and temperature) and future (pH and temperature projected by 2100) ocean conditions. Responses were tested both during the heatwaves, and after a seven-day recovery period. Heatwaves reduced net photosynthetic rates in both current and future conditions, while respiration rates were elevated under heatwaves in the current conditions only. Following the recovery period, there was little evidence of heatwaves having lasting negative effects on growth, photosynthesis or respiration. Exposure to heatwaves, future ocean conditions or both caused an increase in the degree of saturation of fatty acids. This adjustment may have counteracted negative effects of elevated temperatures by decreasing membrane fluidity, which increases at higher temperatures. Furthermore, P. comosa appeared to down-regulate the energetically expensive carbon-concentrating mechanism (CCM) in the future conditions with a reduction in delta(13) C values detected in these treatments. Any saved energy arising from this down-regulation was not invested in growth and was likely invested in the adjustment of fatty acid composition. This adjustment is a mechanism by which P. comosa and other seaweeds may tolerate the negative effects of ocean warming and marine heatwaves through benefits arising from ocean acidification.
|
|
| 4. |
- Hartfiel, N., et al.
(författare)
-
Cost-effectiveness of yoga for managing musculoskeletal conditions in the workplace
- 2017
-
Ingår i: Occupational Medicine. - : Oxford University Press (OUP). - 0962-7480 .- 1471-8405. ; 67:9, s. 687-695
-
Tidskriftsartikel (refereegranskat)abstract
- Background Back pain and musculoskeletal conditions negatively affect the health-related quality of life (HRQL) of employees and generate substantial costs to employers. Aims To assess the cost-effectiveness of yoga for managing musculoskeletal conditions. Methods A randomized controlled trial evaluated an 8-week yoga programme, with a 6-month follow-up, for National Health Service (NHS) employees. Effectiveness in managing musculoskeletal conditions was assessed using repeated-measures generalized linear modelling for the Roland-Morris Disability Questionnaire (RDQ) and the Keele STarT Back Screening Tool. Cost-effectiveness was determined using area-under-the-curve linear regression for assessing HRQL from healthcare and societal perspectives. The incremental cost per quality-adjusted life year (QALY) was also calculated. Sickness absence was measured using electronic staff records at 6 months. Results There were 151 participants. At 6 months, mean differences between groups favouring yoga were observed for RDQ [-0.63 (95% CI, -1.78, 0.48)], Keele STarT [-0.28 (95% CI, -0.97, 0.07)] and HRQL (0.016 QALY gain). From a healthcare perspective, yoga yielded an incremental cost-effectiveness ratio of £2103 per QALY. Given a willingness to pay for an additional QALY of £20 000, the probability of yoga being cost-effective was 95%. From a societal perspective, yoga was the dominant treatment compared with usual care. At 6 months, electronic staff records showed that yoga participants missed a total of 2 working days due to musculoskeletal conditions compared with 43 days for usual care participants. Conclusions Yoga for NHS employees may enhance HRQL, reduce disability associated with back pain, lower sickness absence due to musculoskeletal conditions and is likely to be cost-effective. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved.
|
|
| 5. |
|
|
| 6. |
- Lind, Ulrika, et al.
(författare)
-
Molecular Characterization of the alpha-Subunit of Na+/K+ ATPase from the Euryhaline Barnacle Balanus improvisus Reveals Multiple Genes and Differential Expression of Alternative Splice Variants
- 2013
-
Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
-
Tidskriftsartikel (refereegranskat)abstract
- The euryhaline bay barnacle Balanus improvisus has one of the broadest salinity tolerances of any barnacle species. It is able to complete its life cycle in salinities close to freshwater (3 PSU) up to fully marine conditions (35 PSU) and is regarded as one of few truly brackish-water species. Na+/K+ ATPase (NAK) has been shown to be important for osmoregulation when marine organisms are challenged by changing salinities, and we therefore cloned and examined the expression of different NAKs from B. improvisus. We found two main gene variants, NAK1 and NAK2, which were approximately 70% identical at the protein level. The NAK1 mRNA existed in a long and short variant with the encoded proteins differing only by 27 N-terminal amino acids. This N-terminal stretch was coded for by a separate exon, and the two variants of NAK1 mRNAs appeared to be created by alternative splicing. We furthermore showed that the two NAK1 isoforms were differentially expressed in different life stages and in various tissues of adult barnacle, i.e the long isoform was predominant in cyprids and in adult cirri. In barnacle cyprid larvae that were exposed to a combination of different salinities and pCO(2) levels, the expression of the long NAK1 mRNA increased relative to the short in low salinities. We suggest that the alternatively spliced long variant of the Nak1 protein might be of importance for osmoregulation in B. improvisus in low salinity conditions.
|
|
| 7. |
- Nicol, S., et al.
(författare)
-
Ocean Futures for the World’s Largest Yellowfin Tuna Population Under the Combined Effects of Ocean Warming and Acidification
- 2022
-
Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- The impacts of climate change are expected to have profound effects on the fisheries of the Pacific Ocean, including its tuna fisheries, the largest globally. This study examined the combined effects of climate change on the yellowfin tuna population using the ecosystem model SEAPODYM. Yellowfin tuna fisheries in the Pacific contribute significantly to the economies and food security of Pacific Island Countries and Territories and Oceania. We use an ensemble of earth climate models to project yellowfin populations under a high greenhouse gas emissions (IPCC RCP8.5) scenario, which includes, the combined effects of a warming ocean, increasing acidification and changing ocean chemistry. Our results suggest that the acidification impact will be smaller in comparison to the ocean warming impact, even in the most extreme ensemble member scenario explored, but will have additional influences on yellowfin tuna population dynamics. An eastward shift in the distribution of yellowfin tuna was observed in the projections in the model ensemble in the absence of explicitly accounting for changes in acidification. The extent of this shift did not substantially differ when the three-acidification induced larval mortality scenarios were included in the ensemble; however, acidification was projected to weaken the magnitude of the increase in abundance in the eastern Pacific. Together with intensive fishing, these potential changes are likely to challenge the global fishing industry as well as the economies and food systems of many small Pacific Island Countries and Territories. The modelling framework applied in this study provides a tool for evaluating such effects and informing policy development.
|
|
| 8. |
- Schlegel, Peter, et al.
(författare)
-
Sperm swimming in the polychaete Galeolaria caespitosa shows substantial inter-individual variability in response to future ocean acidification.
- 2014
-
Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X. ; 78:1-2, s. 213-217
-
Tidskriftsartikel (refereegranskat)abstract
- The rapidity of ocean acidification intensifies selection pressure for resilient phenotypes, particularly during sensitive early life stages. The scope for selection is greater in species with greater within-species variation in responses to changing environments, thus enhancing the potential for adaptation. We investigated among-male variation in sperm swimming responses (percent motility and swimming speeds) of the serpulid polychaete Galeolaria caespitosa to near- (ΔpH −0.3) and far-future ocean acidification (ΔpH −0.5). Responses of sperm swimming to acidification varied significantly among males and were overall negative. Robust sperm swimming behavior under near-future ocean acidification in some males may ameliorate climate change impacts, if traits associated with robustness are heritable, and thereby enhance the potential for adaptation to far-future conditions. Reduced sperm swimming in the majority of male G. caespitosa may decrease their fertilization success in a high CO2 future ocean. Resultant changes in offspring production could affect recruitment success and population fitness downstream.
|
|
| 9. |
- Turner, Lucy M., et al.
(författare)
-
Pathogenic marine microbes influence the effects of climate change on a commercially important tropical bivalve
- 2016
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- There is growing evidence that climate change will increase the prevalence of toxic algae and harmful bacteria, which can accumulate in marine bivalves. However, we know little about any possible interactions between exposure to these microorganisms and the effects of climate change on bivalve health, or about how this may affect the bivalve toxin-pathogen load. In mesocosm experiments, mussels, Perna viridis, were subjected to simulated climate change (warming and/or hyposalinity) and exposed to harmful bacteria and/or toxin-producing dinoflagellates. We found significant interactions between climate change and these microbes on metabolic and/or immunobiological function and toxin-pathogen load in mussels. Surprisingly, however, these effects were virtually eliminated when mussels were exposed to both harmful microorganisms simultaneously. This study is the first to examine the effects of climate change on determining mussel toxin-pathogen load in an ecologically relevant, multi-trophic context. The results may have considerable implications for seafood safety.
|
|
| 10. |
- Turner, Lucy M., et al.
(författare)
-
Toxic Algae Silence Physiological Responses to Multiple Climate Drivers in a Tropical Marine Food Chain
- 2019
-
Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Research on the effects of climate change in the marine environment continues to accelerate, yet we know little about the effects of multiple climate drivers in more complex, ecologically relevant settings - especially in sub-tropical and tropical systems. In marine ecosystems, climate change (warming and freshening from land run-oft) will increase water column stratification which is favorable for toxin producing dinoflagellates. This can increase the prevalence of toxic microalgal species, leading to bioaccumulation of toxins by filter feeders, such as bivalves, with resultant negative impacts on physiological performance. In this study we manipulated multiple climate drivers (warming, freshening, and acidification), and the availability of toxic microalgae, to determine their impact on the physiological health, and toxin load of the tropical filter-feeding clam, Meretrix meretrix. Using a structural equation modeling (SEM) approach, we found that exposure to projected marine climates resulted in direct negative effects on metabolic and immunological function and, that these effects were often more pronounced in clams exposed to multiple, rather than single climate drivers. Furthermore, our study showed that these physiological responses were modified by indirect effects mediated through the food chain. Specifically, we found that when bivalves were fed with a toxin-producing dinoflagellate (Alexandrium minutum) the physiological responses, and toxin load changed differently and in a non-predictable way compared to clams exposed to projected marine climates only. Specifically, oxygen consumption data revealed that these clams did not respond physiologically to climate warming or the combined effects of warming, freshening and acidification. Our results highlight the importance of quantifying both direct and, indirect food chain effects of climate drivers on a key tropical food species, and have important implications for shellfish production and food safety in tropical regions.
|
|
| 11. |
- Zaiss, J., et al.
(författare)
-
Impact of Lagrangian Sea Surface Temperature Variability on Southern Ocean Phytoplankton Community Growth Rates
- 2021
-
Ingår i: Global Biogeochemical Cycles. - : American Geophysical Union (AGU). - 0886-6236 .- 1944-9224. ; 35:8
-
Tidskriftsartikel (refereegranskat)abstract
- Ocean phytoplankton play a critical role in the global carbon cycle, contributing similar to 50% of global photosynthesis. As planktonic organisms, phytoplankton encounter significant environmental variability as they are advected throughout the ocean. How this variability impacts phytoplankton growth rates and population dynamics remains unclear. Here, we systematically investigated the impact of different rates and magnitudes of sea surface temperature (SST) variability on phytoplankton community growth rates using surface drifter observations from the Southern Ocean (>30 degrees S) and a phenotype-based ecosystem model. Short-term SST variability (<7 days) had a minimal impact on phytoplankton community growth rates. Moderate SST changes of 3-4 degrees C over 7-45 days produced a large time lag between the temperature change and the biological response. The impact of SST variability on community growth rates was nonlinear and a function of the rate and magnitude of change. Additionally, the nature of variability generated in a Lagrangian reference frame (following trajectories of surface water parcels) was larger than that within an Eulerian reference frame (fixed point), which initiated different phytoplankton responses between the two reference frames. Finally, we found that these dynamics were not captured by the Eppley growth model commonly used in global biogeochemical models and resulted in an overestimation of community growth rates, particularly in dynamic, strong frontal regions of the Southern Ocean. This work demonstrates that the timescale for environmental selection (community replacement) is a critical factor in determining community composition and takes a first step towards including the impact of variability and biological response times into biogeochemical models.
|
|
| 12. |
- Alsterberg, Christian, 1982, et al.
(författare)
-
Consumers mediate the effects of experimental ocean acidification and warming on primary producers.
- 2013
-
Ingår i: Proceedings of the National Academy of Science of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 110:21, s. 8603-8608
-
Tidskriftsartikel (refereegranskat)abstract
- It is well known that ocean acidification can have profound impacts on marine organisms. However, we know little about the direct and indirect effects of ocean acidification and also how these effects interact with other features of environmental change such as warming and declining consumer pressure. In this study, we tested whether the presence of consumers (invertebrate mesograzers) influenced the interactive effects of ocean acidification and warming on benthic microalgae in a seagrass community mesocosm experiment. Net effects of acidification and warming on benthic microalgal biomass and production, as assessed by analysis of variance, were relatively weak regardless of grazer presence. However, partitioning these net effects into direct and indirect effects using structural equation modeling revealed several strong relationships. In the absence of grazers, benthic microalgae were negatively and indirectly affected by sediment-associated microalgal grazers and macroalgal shading, but directly and positively affected by acidification and warming. Combining indirect and direct effects yielded no or weak net effects. In the presence of grazers, almost all direct and indirect climate effects were nonsignificant. Our analyses highlight that (i) indirect effects of climate change may be at least as strong as direct effects, (ii) grazers are crucial in mediating these effects, and (iii) effects of ocean acidification may be apparent only through indirect effects and in combination with other variables (e.g., warming). These findings highlight the importance of experimental designs and statistical analyses that allow us to separate and quantify the direct and indirect effects of multiple climate variables on natural communities.
|
|
| 13. |
- Appelqvist, Christin, 1972, et al.
(författare)
-
A phenological shift in the time of recruitment of the shipworm, Teredo navalis L., mirrors marine climate change
- 2016
-
Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 6:12, s. 3862-3870
-
Tidskriftsartikel (refereegranskat)abstract
- For many species, seasonal changes in key environmental variables such as food availability, light, and temperature drive the timing ("phenology") of major life-history events. Extensive evidence from terrestrial, freshwater, and marine habitats shows that global warming is changing the timings of many biological events; however, few of these studies have investigated the effects of climate change on the phenology of larval recruitment in marine invertebrates. Here, we studied temperature-related phenological shifts in the breeding season of the shipworm Teredo navalis (Mollusca, Bivalvia). We compared data for the recruitment period of T. navalis along the Swedish west coast during 20042006 with similar data from 1971-1973, and related differences in recruitment timing to changes in sea surface temperature over the same period. We found no significant shift in the timing of onset of recruitment over this similar to 30-year time span, but the end of recruitment was an average of 26 days later in recent years, leading to significantly longer recruitment periods. These changes correlated strongly with increased sea surface temperatures and coincided with published thermal tolerances for reproduction in T. navalis. Our findings are broadly comparable with other reports of phenological shifts in marine species, and suggest that warmer sea surface temperatures are increasing the likelihood of successful subannual reproduction and intensifying recruitment of T. navalis in this region.
|
|
| 14. |
- Appelqvist, Christin, 1972, et al.
(författare)
-
Climate envelope modeling and dispersal simulations show little risk of range extension of the shipworm, Teredo navalis (L.), in the Baltic Sea
- 2015
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:3
-
Tidskriftsartikel (refereegranskat)abstract
- The shipworm, Teredo navalis , is absent from most of the Baltic Sea. In the last 20 years, increased frequency of T. navalis has been reported along the southern Baltic Sea coasts of Denmark, Germany, and Sweden, indicating possible range-extensions into previously unoccupied areas. We evaluated the effects of historical and projected near-future changes in salinity, temperature, and oxygen on the risk of spread of T. navalis in the Baltic. Specifically, we developed a simple, GIS-based, mechanistic climate envelope model to predict the spatial distribution of favourable conditions for adult reproduction and larval metamorphosis of T. navalis, based on published environmental tolerances to these factors. In addition, we used a high-resolution three-dimensional hydrographic model to simulate the probability of spread of T. navalis larvae within the study area. Climate envelope modeling showed that projected near-future climate change is not likely to change the overall distribution of T. navalis in the region, but will prolong the breeding season and increase the risk of shipworm establishment at the margins of the current range. Dispersal simulations indicated that the majority of larvae were philopatric, but those that spread over a wider area typically spread to areas unfavourable for their survival. Overall, therefore, we found no substantive evidence for climate-change related shifts in the distribution of T. navalis in the Baltic Sea, and no evidence for increased risk of spread in the near-future. © 2015 Appelqvist et al.
|
|
| 15. |
|
|
| 16. |
- Appelqvist, Christin, 1972, et al.
(författare)
-
Distribution and abundance of teredinid recruits along the Swedish coast - are shipworms invading the Baltic Sea?
- 2015
-
Ingår i: Journal of the Marine Biological Association of the United Kingdom. - 0025-3154 .- 1469-7769. ; 95:4, s. 783-790
-
Tidskriftsartikel (refereegranskat)abstract
- Shipworms (teredinids) are highly specialized marine bivalves that consume terrestrially derived wood. Changes in environmental variables may result in shipworms spreading into the Baltic Sea – which would have devastating consequences for maritime cultural heritage and submerged wooden structures. We investigated the distribution and abundance of the shipworms Teredo navalis and Psiloteredo megotara along the Swedish coast in 2006–2008, and compared our findings with data collected at partly the same locations in 1971–1973. Wooden test panels were submerged in near-surface waters at 18 harbours. The presence of shipworms was determined by X-ray radiography of each panel. Sea surface temperature and salinity data were analysed to investigate whether any changes in distribution were correlated to changes in environmental variables. We found that past and present distributions of T. navalis were similar – indicating that no range expansion of shipworms into the Baltic Sea has taken place the last 35 years. The abundance of T. navalis was similar between decades at all investigated sites except two (Arild and Barsebäckshamn), where abundances were higher in 2006–2008. The abundance of T. navalis varied along the coast and was positively correlated to mean sea surface salinity, but not to mean sea surface temperature (2006–2008 data). The distribution and abundance of P. megotara were similar during the two study periods with only single observations at a few sites. In conclusion, we found no evidence of range expansion of shipworms along the Swedish coast.
|
|
| 17. |
- Aronson, Richard, et al.
(författare)
-
No barrier to emergence of bathyal king crabs on the Antarctic shelf
- 2015
-
Ingår i: Proceedings of the National Academy of Science of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:42, s. 12997-13002
-
Tidskriftsartikel (refereegranskat)abstract
- Cold-water conditions have excluded durophagous (skeleton-breaking) predators from the Antarctic seafloor for millions of years. Rapidly warming seas off the western Antarctic Peninsula could now facilitate their return to the continental shelf, with profound consequences for the endemic fauna. Among the likely first arrivals are king crabs (Lithodidae), which were discovered recently on the adjacent continental slope. During the austral summer of 2010‒2011, we used underwater imagery to survey a slope-dwelling population of the lithodid Paralomis birsteini off Marguerite Bay, western Antarctic Peninsula for environmental or trophic impediments to shoreward expansion. The population density averaged ∼4.5 individuals × 1,000 m−2 within a depth range of 1,100‒1,500 m (overall observed depth range 841–2,266 m). Images of juveniles, discarded molts, and precopulatory behavior, as well as gravid females in a trapping study, suggested a reproductively viable population on the slope. At the time of the survey, there was no thermal barrier to prevent the lithodids from expanding upward and emerging on the outer shelf (400- to 550-m depth); however, near-surface temperatures remained too cold for them to survive in inner-shelf and coastal environments (<200 m). Ambient salinity, composition of the substrate, and the depth distribution of potential predators likewise indicated no barriers to expansion of lithodids onto the outer shelf. Primary food resources for lithodids—echinoderms and mollusks—were abundant on the upper slope (550–800 m) and outer shelf. As sea temperatures continue to rise, lithodids will likely play an increasingly important role in the trophic structure of subtidal communities closer to shore.
|
|
| 18. |
- Bachimanchi, Harshith, et al.
(författare)
-
Deep-learning-powered data analysis in plankton ecology
- 2024
-
Ingår i: Limnology And Oceanography Letters. - 2378-2242.
-
Forskningsöversikt (refereegranskat)abstract
- The implementation of deep learning algorithms has brought new perspectives to plankton ecology. Emerging as an alternative approach to established methods, deep learning offers objective schemes to investigate plankton organisms in diverse environments. We provide an overview of deep-learning-based methods including detection and classification of phytoplankton and zooplankton images, foraging and swimming behavior analysis, and finally ecological modeling. Deep learning has the potential to speed up the analysis and reduce the human experimental bias, thus enabling data acquisition at relevant temporal and spatial scales with improved reproducibility. We also discuss shortcomings and show how deep learning architectures have evolved to mitigate imprecise readouts. Finally, we suggest opportunities where deep learning is particularly likely to catalyze plankton research. The examples are accompanied by detailed tutorials and code samples that allow readers to apply the methods described in this review to their own data.
|
|
| 19. |
- Björdal, Charlotte, 1961, et al.
(författare)
-
Strategies for protection of wooden underwater cultural heritage in the Baltic sea against marine borers. The EU project "WreckProtect"
- 2012
-
Ingår i: Conservation and Management of Archeological Sites. - 1350-5033. ; 14:1-4, s. 201-214
-
Tidskriftsartikel (refereegranskat)abstract
- Marine borers constitute a great danger to historical shipwreck in marine environments as they are able to decompose wood material in just a few years. Recently, there have been indications that the marine borer Teredo navalis is spreading into the brackish Baltic sea, where thousands of invaluable historical wrecks for centuries have had unique preservation conditions. The WreckProtect project was a coordination and support action funded by the European Commission within the 7th Framework Program. The main objective of the project was to develop tools for predicting the spread of marine borers into the Baltic and to evaluate methods for in situ protection of the historical wreck and submerged settlements. This paper gives a summary final report of the project and an overview of results.
|
|
| 20. |
- Bolton, T. F., et al.
(författare)
-
Physiological acclimation to decreased water temperature and the relative importance of water viscosity in determining the feeding performance of larvae of a serpulid polychaete
- 2005
-
Ingår i: Journal of Plankton Research. - : Oxford University Press (OUP). - 0142-7873 .- 1464-3774. ; 27:9, s. 875-879
-
Tidskriftsartikel (refereegranskat)abstract
- Ambient temperature exerts both physiological and mechanical effects on the rates of functional processes of small aquatic ectotherms. Physiological effects of temperature result from its influence on the rates of chemical reactions. Mechanical effects of temperature result from the inverse relationship between the temperature of water and its dynamic viscosity. We measured the relative importance of these components of temperature on the feeding performance of polychaete larvae. Cohorts of larvae were reared for 24 h at 20 degrees C and 10 degrees C in treatments where the physiological and mechanical effects of these temperatures were separated. The feeding performance of these larvae was subsequently measured in treatments where these components of temperature were similarly partitioned. Cold-reared larvae displayed complete acclimation of feeding performance to the physiological effects of decreased temperature: thus, increased viscosity was responsible for 100% of the difference in feeding performance between 20 degrees C and 10 degrees C. The physiological ability of small aquatic ectotherms to acclimate functional processes to temperature variation may be greater than previously thought, and these results have implications for understanding the responses of aquatic ectotherms' to global temperature change.
|
|
| 21. |
- Boyd, Philip, et al.
(författare)
-
Handbook to support the SCOR Best Practice Guide for ‘Multiple Drivers’ Marine Research
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Marine species and ecosystems are exposed to a wide range of environmental change – both detrimental (threats) and beneficial – due to human activities. Some of the changes are global, whereas others are regional or local. It is important to distinguish the scale of each threat as the solutions will differ. For example, the mitigation of a global problem requires a global response, which is more difficult to achieve than addressing a local problem with a local response. These wide-ranging changes are often referred to drivers or stressors.
|
|
| 22. |
- Boyd, P. W., et al.
(författare)
-
Experimental strategies to assess the biological ramifications of multiple drivers of global ocean change-A review
- 2018
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013. ; 24:6, s. 2239-2261
-
Tidskriftsartikel (refereegranskat)abstract
- Marine life is controlled by multiple physical and chemical drivers and by diverse ecological processes. Many of these oceanic properties are being altered by climate change and other anthropogenic pressures. Hence, identifying the influences of multifaceted ocean change, from local to global scales, is a complex task. To guide policy-making and make projections of the future of the marine biosphere, it is essential to understand biological responses at physiological, evolutionary and ecological levels. Here, we contrast and compare different approaches to multiple driver experiments that aim to elucidate biological responses to a complex matrix of ocean global change. We present the benefits and the challenges of each approach with a focus on marine research, and guidelines to navigate through these different categories to help identify strategies that might best address research questions in fundamental physiology, experimental evolutionary biology and community ecology. Our review reveals that the field of multiple driver research is being pulled in complementary directions: the need for reductionist approaches to obtain processoriented, mechanistic understanding and a requirement to quantify responses to projected future scenarios of ocean change. We conclude the review with recommendations on how best to align different experimental approaches to contribute fundamental information needed for science-based policy formulation.
|
|
| 23. |
- Brander, Keith, et al.
(författare)
-
Impacts of climate change, including acidification, on marine ecosystems and fisheries.
- 2012
-
Ingår i: Climate impacts on the Baltic Sea: from science to policy. - Berlin : Springer. - 9783642257278 ; , s. 129-160
-
Bokkapitel (refereegranskat)abstract
- arine ecosystems have always been affected by changes in climate at timescales from decades to millions of years. Since the industrial revolution in the nineteenth century the increase in greenhouse gases (GHG) has caused an accelerating rise in global temperature whose effects on marine biota can be detected at individual, population and ecosystem level. The rising level of CO2 and consequent acidification of the oceans is having an impact on metabolism and calcification in many organisms, with damage to vulnerable ecosystems, such as coral reefs, already occurring. The pH of the oceans is already lower now than it has been for the past 600,000 years.
|
|
| 24. |
- Bromhead, D., et al.
(författare)
-
The potential impact of ocean acidification on eggs and larvae of the Yellowfin Tuna.
- 2015
-
Ingår i: Deep-sea research. Part II, Topical studies in oceanography. - : Elsevier BV. - 0967-0645. ; 113, s. 268-279
-
Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic carbon dioxide (CO2) emissions are resulting in increasing absorption of CO2 by the earth's oceans, which has led to a decline in ocean pH, a process known as ocean acidification (OA). Evidence suggests that OA may have the potential to affect the distribution and population dynamics of many marine organisms. Early life history processes (e.g. fertilization) and stages (eggs, larvae, juveniles) may be relatively more vulnerable to potential OA impacts, with implications for recruitment in marine populations. The potential impact of OA upon tuna populations has not been investigated, although tuna are key components of pelagic ecosystems and, in the Pacific Ocean, form the basis of one of the largest and most valuable fisheries in the world. This paper reviews current knowledge of potential OA impacts on fish and presents results from a pilot study investigating how OA may affect eggs and larvae of yellowfin tuna, Thunnus albacares. Two separate trials were conducted to test the impact of pCO2 on yellowfin egg stage duration, larval growth and survival. The pCO2 levels tested ranged from present day ($400 μatm) to levels predicted to occur in some areas of the spawning habitat within the next 100 years (o2500 μatm) to 300 years ($ o5000 μatm) to much more extreme levels ($10,000 μatm). In trial 1, there was evidence for significantly reduced larval survival (at mean pCO2 levelsZ4730 μatm) and growth (at mean pCO2 levels Z 2108 μatm), while egg hatch time was increased at extreme pCO2 levelsZ10,000 μatm (nintermediate levels were not tested). In trial 2, egg hatch times were increased at mean pCO2 levelsZ1573 μatm, but growth was only impacted at higher pCO2 (Z8800 μatm) and there was no relationship with survival. Unstable ambient conditions during trial 2 are likely to have contributed to the difference in results between trials. Despite the technical challenges with these experiments, there is a need for future empirical work which can in turn support modeling-based approaches to assess how OA will affect the ecologically and economically important tropical tuna resources.
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
|
|
| 28. |
|
|
| 29. |
- Eklöf, Johan, 1978, et al.
(författare)
-
Community-level effects of rapid experiment warming and consumer loss outweigh effects of rapid ocean acidification.
- 2015
-
Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 124:8, s. 1040-1049
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change and consumer loss simultaneously affect marine ecosystems, but we have limited understanding of the relative importance of these factors and the interactions between them. Moreover, effects of environmental change are mediated by organism traits or life histories, which determine their sensitivity. Yet, trait-based analyses have rarely been used to understand the effects of climate change, especially in the marine environment. Here we used a five-week mesocosm experiment to assess the single and interactive effects of 1) rapid ocean warming, 2) rapid ocean acidification, and 3) simulated consumer loss, on the diversity and composition of macrofauna communities in eelgrass Zostera marina beds. Experimental warming (ambient versus + 3.2°C) and loss of a key consumer (the omnivorous crustacean, Gammarus locusta) both increased macrofauna richness and abundance, and altered overall species trait distributions and life history composition. Warming and consumer-loss favored poorly defended epifaunal crustaceans (tube-building amphipods), and species that brood their offspring. We suggest these organisms were favored because warming and consumer-loss caused increased metabolism, food supply and, potentially, settling substrate, and lowered predation pressure from the omnivorous G. locusta. Importantly, we found no single, or interactive, effects of the rapid ocean acidification (ambient versus −0.35 pH units). We suggest this result reflects natural variability in the native habitat and, potentially, the short duration of the experiment: organisms in these communities routinely experience rapid diurnal pH fluctuations that exceed the mean ocean acidification predicted for the coming century (and used in our experiments). In summary, our study indicates that macrofauna in shallow vegetated ecosystems will be significantly more affected by rapid warming and consumer diversity loss than by rapid ocean acidification.
|
|
| 30. |
|
|
| 31. |
- Eklöf, Johan, 1978, et al.
(författare)
-
Experimental climate change weakens the insurance effect of biodiversity
- 2012
-
Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 15:8, s. 864-872
-
Tidskriftsartikel (refereegranskat)abstract
- Ecosystems are simultaneously affected by biodiversity loss and climate change, but we know little about how these factors interact. We predicted that climate warming and CO 2-enrichment should strengthen trophic cascades by reducing the relative efficiency of predation-resistant herbivores, if herbivore consumption rate trades off with predation resistance. This weakens the insurance effect of herbivore diversity. We tested this prediction using experimental ocean warming and acidification in seagrass mesocosms. Meta-analyses of published experiments first indicated that consumption rate trades off with predation resistance. The experiment then showed that three common herbivores together controlled macroalgae and facilitated seagrass dominance, regardless of climate change. When the predation-vulnerable herbivore was excluded in normal conditions, the two resistant herbivores maintained top-down control. Under warming, however, increased algal growth outstripped control by herbivores and the system became algal-dominated. Consequently, climate change can reduce the relative efficiency of resistant herbivores and weaken the insurance effect of biodiversity.
|
|
| 32. |
- Eriander, Louise, 1984, et al.
(författare)
-
Simulated diurnal pH fluctuations radically increase variance in— but not the mean of—growth in the barnacle Balanus improvisus
- 2016
-
Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 73:3, s. 596-603
-
Tidskriftsartikel (refereegranskat)abstract
- Shallow coastal waters are characterized by substantial diurnal fluctuations in pH, especially in nearshore environments. The biological effects of ocean acidification in combination with these natural fluctuations have received relatively little attention to date. We exposed multiple batches (≈ different genotypes) of newly settled barnacles, Balanus improvisus, to constant pH under “control” (pH ¼ 8.1) or “stable acidified” (pH ¼ 7.7) conditions, as well as a treatment that simulated the maximum diurnal pH fluctuations seen in the nearshore habitats where this barnacle lives (+0.2 pH units), superimposed on the stable acidified treatment (“fluctuating acidified”; 7.5 ≤ pH ≤ 7.9). We found that fluctuating acidification had no effect on mean response in growth and shell mineralogy, but caused an #20-fold increase in variance of responses, compared with stable acidification. In contrast to these results, we found no effect of fluctuating acidification on variances of response ratios for barnacle survival and shell strength. Similarly, mean survival did not vary significantly with pH. However, we observed a strong negative effect of stable and fluctuating acidification on mean shell strength. Our finding that barnacles respond differently to fluctuating pHthan to stable lowpH indicate the importance of including fluctuating acidification treatments when studying species that live in variable environments. Importantly, because phenotypic variance is the raw material for natural selection, and thus lays at the heart of evolutionary responses to environmental variability and change, our findings also highlight the need to study changes in variance of—as well as mean—responses to changing ocean climates.
|
|
| 33. |
- Falkenberg, L. J., et al.
(författare)
-
Low sensitivity of reproductive life-stages in the Pacific oyster (Crassostrea gigas) to abamectin
- 2017
-
Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535. ; 182, s. 665-671
-
Tidskriftsartikel (refereegranskat)abstract
- Hard surfaces submerged in the marine environment often become colonised by macro-organisms unless the surfaces have some form of biofouling protection. While protective paints that contain tributyltin or copper work well to prevent biofouling, release of these materials into the environment has been shown to have wider negative impacts. Consequently, new low-release antifouling paints are being developed with alternative active ingredients, such as avermectins, yet little is known about their potential effects on non-target organisms in marine environments. Here we investigated the toxicity of a key avermectin, specifically abamectin, on several aspects of reproduction (sperm motility, fertilisation success, early larval development) in the Pacific oyster, Crassostrea gigas. Oyster reproduction was generally insensitive to the low concentrations of abamectin, although greater concentrations of abamectin did negatively affect all three endpoints – LOECs were 1000μgl−1, 500μgl−1, and 100μgl−1 abamectin for sperm motility, fertilisation success, and larval development, respectively. A similar pattern was found in the EC50s of the three endpoints (mean±SE) 934±59μgl−1, 1076.26±725.61μgl−1, and 140±78μgl−1 abamectin (sperm motility, fertilisation success, and larval development, respectively). Together, these results clearly indicate that of the three endpoints considered, larval development was more sensitive to abamectin (lower LOEC, EC50) than fertilisation success and sperm motility. Although more data are needed from a wider range of marine species and environments to fully assess potential toxicity effects on non-target organisms, our results highlight the potential utility of abamectin in low-release antifouling paints. © 2017 Elsevier Ltd
|
|
| 34. |
- Falkenberg, L. J., et al.
(författare)
-
Sperm Accumulated Against Surface: A novel alternative bioassay for environmental monitoring
- 2016
-
Ingår i: Marine Environmental Research. - : Elsevier BV. - 0141-1136. ; 114, s. 51-57
-
Tidskriftsartikel (refereegranskat)abstract
- Forecasting the impacts of changes in water quality on broadcast spawning aquatic organisms is a key aspect of environmental monitoring. Rapid assays of reproductive potential are central to this monitoring, and there is a need to develop a variety of methods to identify responses. Here, we report a proof of-concept study that assesses whether quantification of "Sperm Accumulated Against Surface" (SAAS) of tissue culture well-plates could be a rapid and simple proxy measure of fertilisation success. Our results confirm that motile sperm (but not immotile sperm) actively accumulate at surfaces and that the pattern of accumulation reflects fertilisation success in the model oyster species Crassostrea gigas. Furthermore, we confirm these patterns of SAAS for another marine species, the polychaete Galeolaria caespitosa, as well as for a freshwater species, the fish Gasterosteus aculeatus. For all species considered, SAAS reflected changes in sperm performance caused by experimentally manipulated differences in water quality (here, salinity). These findings indicate that SAAS could be applied easily to a range of species when examining the effects of water quality. Measurement of SAAS could, therefore, form the basis of a rapid and reliable assay for bioassessments of broadcast spawning aquatic organisms. (C) 2015 Elsevier Ltd. All rights reserved.
|
|
| 35. |
- Falkenberg, L. J., et al.
(författare)
-
Sperm motility of oysters from distinct populations differs in response to ocean acidification and freshening
- 2019
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
-
Tidskriftsartikel (refereegranskat)abstract
- Species' responses to climate change will reflect variability in the effects of physiological selection that future conditions impose. Here, we considered the effects of ocean acidification (increases in pCO(2); 606, 925, 1250 mu atm) and freshening (reductions in salinity; 33, 23, 13 PSU) on sperm motility in oysters (Crassostrea gigas) from two populations (one recently invaded, one established for 60+ years). Freshening reduced sperm motility in the established population, but this was offset by a positive effect of acidification. Freshening also reduced sperm motility in the recently invaded population, but acidification had no effect. Response direction, strength, and variance differed among individuals within each population. For the established population, freshening increased variance in sperm motility, and exposure to both acidification and freshening modified the performance rank of males (i.e. rank motility of sperm). In contrast, for the recently invaded population, freshening caused a smaller change in variance, and male performance rank was broadly consistent across treatments. That inter-population differences in response may be related to environmental history (recently invaded, or established), indicates this could influence scope for selection and adaptation. These results highlight the need to consider variation within and among population responses to forecast effects of multiple environmental change drivers.
|
|
| 36. |
- Frommel, Andrea, et al.
(författare)
-
Effect of ocean acidification on marine fish sperm (Baltic cod: Gadus morhua)
- 2011
-
Ingår i: Biogeosiences. - 1726-4170. ; 7:12, s. 3915-3919
-
Tidskriftsartikel (refereegranskat)abstract
- Ocean acidification, as a consequence of increasing marine pCO(2), may have severe effects on the physiology of marine organisms. However, experimental studies remain scarce, in particular concerning fish. While adults will most likely remain relatively unaffected by changes in seawater pH, early life-history stages are potentially more sensitive - particularly the critical stage of fertilization, in which sperm motility plays a central role. In this study, the effects of ocean acidification (decrease of pH(T) to 7.55) on sperm motility of Baltic cod, Gadus morhua, were assessed. We found no significant effect of decreased pH on sperm speed, rate of change of direction or percent motility for the population of cod analyzed. We predict that future ocean acidification will probably not pose a problem for sperm behavior, and hence fertilization success, of Baltic cod.
|
|
| 37. |
- Frommel, A. Y., et al.
(författare)
-
Ocean acidification has lethal and sub-lethal effects on larval development of yellowfin tuna, Thunnus albacares
- 2016
-
Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981. ; 482, s. 18-24
-
Tidskriftsartikel (refereegranskat)abstract
- Ocean acidification (OA), the process by which increasing atmospheric CO2 is absorbed by the ocean, lowering the pH of surface waters, has been shown to affect many marine organisms negatively. It has been suggested that organisms from regions with naturally low pH waters, such as upwelling areas, could serve as models for future effects of OA and may be adapted to increased pCO(2) levels. In this study, we examined the effects of OA on yellowfin tuna, a highly pelagic species that spawns in the eastern tropical Pacific, an area that includes regions of strong upwelling events. Larvae reared at decreasing pH levels (pH 8.1, 7.6, 7.3 and 6.9) showed increasing organ damage in the kidney, liver, pancreas, eye and muscle, which correlated with decreased growth and survival. These findings complement earlier studies on organ damage in Atlantic cod and herring larvae and demonstrate that OA may have detrimental effects on fish larvae, regardless of their pre-exposure to low pH waters.
|
|
| 38. |
- Gamfeldt, Lars, 1975, et al.
(författare)
-
Increasing intraspecific diversity enhances settling success in a marine invertebrate
- 2005
-
Ingår i: Ecology. - : Wiley. - 0012-9658. ; 86:12, s. 3219-3224
-
Tidskriftsartikel (refereegranskat)abstract
- Theoretical and empirical research during the last decade suggests that increasing species richness often enhances ecosystem processes Such as productivity, nutrient cycling. or resistance to disturbance. By analogous reasoning, it can be hypothesized that genetic diversity within species will have equivalent effects; however, this hypothesis has rarely been tested. We present experimental support for the positive effects of intraspecific diversity on a key trait: larval settlement in a marine invertebrate, the barnacle Balanus improvisus. Varying within-species diversity levels of an animal over nine experiments, We found increasing larval settlement with increasing diversity (one, two, or three parental broods). Possible mechanisms explaining this pattern include: (1) facilitation of gregarious response through the presence of founder genotypes, and (2) ensuring genetic complementarity to increase future reproductive potential. Our results indicate that changing intraspecific genetic diversity could have hitherto unrecognized community-scale implications for larval recruitment and space occupancy.
|
|
| 39. |
- Green, Leon, et al.
(författare)
-
Ancestral Sperm Ecotypes Reveal Multiple Invasions of a Non-Native Fish in Northern Europe
- 2021
-
Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 10:7
-
Tidskriftsartikel (refereegranskat)abstract
- For externally fertilising organisms in the aquatic environment, the abiotic fertilisation medium can be a strong selecting force. Among bony fishes, sperm are adapted to function in a narrow salinity range. A notable exception is the family Gobiidae, where several species reproduce across a wide salinity range. The family also contains several wide-spread invasive species. To better understand how these fishes tolerate such varying conditions, we measured sperm performance in relation to salinity from a freshwater and a brackish population within their ancestral Ponto-Caspian region of the round goby, Neogobius melanostomus. These two ancestral populations were then compared to nine additional invaded sites across northern Europe, both in terms of their sperm traits and by using genomic SNP markers. Our results show clear patterns of ancestral adaptations to freshwater and brackish salinities in their sperm performance. Population genomic analyses show that the ancestral ecotypes have generally established themselves in environments that fit their sperm adaptations. Sites close to ports with intense shipping show that both outbreeding and admixture can affect the sperm performance of a population in a given salinity. Rapid adaptation to local conditions is also supported at some sites. Historical and contemporary evolution in the traits of the round goby sperm cells is tightly linked to the population and seascape genomics as well as biogeographic processes in these invasive fishes. Since the risk of a population establishing in an area is related to the genotype by environment match, port connectivity and the ancestry of the round goby population can likely be useful for predicting the species spread.
|
|
| 40. |
- Green, Leon, et al.
(författare)
-
Evidence of rapid adaptive trait change to local salinity in the sperm of an invasive fish
- 2020
-
Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 13:3, s. 533-544
-
Tidskriftsartikel (refereegranskat)abstract
- Invasive species may quickly colonize novel environments, which could be attributed to both phenotypic plasticity and an ability to locally adapt. Reproductive traits are expected to be under strong selection when the new environment limits reproductive success of the invading species. This may be especially important for external fertilizers, which release sperm and eggs into the new environment. Despite adult tolerance to high salinity, the invasive fish Neogobius melanostomus (round goby) is absent from fully marine regions of the Baltic Sea, raising the possibility that its distribution is limited by tolerance during earlier life stages. Here, we investigate the hypothesis that the spread of N. melanostomus is limited by sperm function in novel salinities. We sampled sperm from two invasion fronts with higher and lower salinities in the Baltic Sea and tested them across a range of salinity levels. We found that sperm velocity and percentage of motile sperm declined in salinity levels higher and lower than those currently experienced by the Baltic Sea populations, with different performance curves for the two fronts. Sperm velocity also peaked closer to the home salinity conditions in each respective invasion front, with older localities showing an increased fit to local conditions. By calculating how the sperm velocity has changed over generations, we show this phenotypic shift to be in the range of other fish species under strong selection, indicating ongoing local adaptation or epigenetic acclimation to their novel environment. These results show that while immigrant reproductive dysfunction appears to at least partly limit the distribution of invasive N. melanostomus in the Baltic Sea, local adaptation to novel environments could enable future spread beyond their current boundaries.
|
|
| 41. |
- Green, Leon, et al.
(författare)
-
Sperm performance limits the reproduction of an invasive fish in novel salinities
- 2021
-
Ingår i: Diversity and Distributions. - : Wiley. - 1366-9516 .- 1472-4642. ; 27:6, s. 1091-1105
-
Tidskriftsartikel (refereegranskat)abstract
- Aim: The few fish species able to reproduce across wide osmotic ranges either plastically acclimate sperm performance to, or are locally adapted to, different salinities. The invasive round goby (Neogobius melanostomus) is spreading in Eurasia and the Americas, into both fresh and brackish water. We aim to understand if reproduction in different salinities is affected by an ability to acclimate. Location: Brackish and freshwater systems of northern Europe and the Baltic Sea. Methods: We cross-exposed round gobies of freshwater and brackish origin to 0 and 16 practical salinity units (PSU), and the fish were given nest boxes in which to spawn. After 4weeks, we measured their sperm performance in both 0 and 16 PSU; fertilization success of each egg clutch was measured through visual analysis of eggs. Clutches were split and allowed to develop in both 0 and 16 PSU salinity, and reproductive success (zygote development) was measured 20±1days later. Responses were analysed using generalized mixed models. Results: After a month, the fish showed no plasticity in sperm performance to their acclimation salinity, regardless of their origin. Sperm velocity was highest in the salinity similar to the males’ origin. Significantly lower fertilization success was measured for individuals that reproduced outside their salinity of origin despite recurring spawning events in all treatment groups. Among fertilized eggs, zygote development was similar regardless of salinity treatment of either eggs or parents. Main Conclusions: Short-term acclimation to new salinities does not affect sperm performance in the round goby. Alternative hypotheses such as local adaption should be further investigated. Limits to the species’ reproductive success, and therefore invasion processes, are likely dependent on environment-phenotype matches. Fish of brackish origin spawned successfully in freshwater, pointing to an increased risk of introducing populations of brackish origin into freshwater.
|
|
| 42. |
|
|
| 43. |
- Hartfiel, Ned, et al.
(författare)
-
Yoga for reducing perceived stress and back pain at work.
- 2012
-
Ingår i: Occupational Medicine. - : Oxford University Press (OUP). - 0962-7480 .- 1471-8405. ; 62:8, s. 606-612
-
Tidskriftsartikel (refereegranskat)abstract
- Background Stress and back pain are two key factors leading to sickness absence at work. Recent research indicates that yoga can be effective for reducing perceived stress, alleviating back pain, and improving psychological well-being. Aims To determine the effectiveness of a yoga-based intervention for reducing perceived stress and back pain at work. Methods Participants were recruited from a British local government authority and randomized into a yoga group who received one 50min Dru Yoga session each week for 8 weeks and a 20min DVD for home practice and a control group who received no intervention. Baseline and end-programme measurements of self-reported stress, back pain and psychological well-being were assessed with the Perceived Stress Scale, Roland Morris Disability Questionnaire and the Positive and Negative Affect Scale. Results There were 37 participants in each group. Analysis of variance and multiple linear regression showed that in comparison to the control group, the yoga group reported significant reductions in perceived stress and back pain, and a substantial improvement in psychological well-being. When compared with the control group at the end of the programme, the yoga group scores were significantly lower for perceived stress, back pain, sadness and hostility, and substantially higher for feeling self-assured, attentive and serene. Conclusions The results indicate that a workplace yoga intervention can reduce perceived stress and back pain and improve psychological well-being. Larger randomized controlled trials are needed to determine the broader efficacy of yoga for improving workplace productivity and reducing sickness absence.
|
|
| 44. |
- Hattich, G. S. I., et al.
(författare)
-
Temporal variation in ecological and evolutionary contributions to phytoplankton functional shifts
- 2023
-
Ingår i: Limnology and Oceanography. - : Wiley. - 0024-3590 .- 1939-5590. ; 68:2, s. 297-306
-
Tidskriftsartikel (refereegranskat)abstract
- Communities and their functioning are jointly shaped by ecological and evolutionary processes that manifest in diversity shifts of their component species and genotypes. How both processes contribute to community functional change over time is rarely studied. We here repeatedly quantified eco-evolutionary contributions to CO2-driven total abundance and mean cell size changes after short-, mid-, and longer-term (80, 168, and >168d, respectively) in experimental phytoplankton communities. While the CO2-driven changes in total abundance and mean size in the short- and mid-term could be predominantly attributed to ecological shifts, the relative contribution of evolution increased. Over the longer-term, the CO2-effect and underlying eco-evolutionary changes disappeared, while total abundance increased, and mean size decreased significantly independently of CO2. The latter could be presumably attributed to CO2-independent genotype selection which fed back to species composition. In conclusion, ecological changes largely dominated the regulation of environmentally driven phytoplankton functional shifts at first. However, evolutionary changes gained importance with time, and can ultimately feedback on species composition, and thus must be considered when predicting phytoplankton change.
|
|
| 45. |
- Havenhand, Jonathan N., 1959, et al.
(författare)
-
Ecological and functional consequences of coastal ocean acidification : Perspectives from the Baltic-Skagerrak System
- 2019
-
Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 48:8, s. 831-854
-
Forskningsöversikt (refereegranskat)abstract
- Ocean temperatures are rising; species are shifting poleward, and pH is falling (ocean acidification, OA). We summarise current understanding of OA in the brackish Baltic-Skagerrak System, focussing on the direct, indirect and interactive effects of OA with other anthropogenic drivers on marine biogeochemistry, organisms and ecosystems. Substantial recent advances reveal a pattern of stronger responses (positive or negative) of species than ecosystems, more positive responses at lower trophic levels and strong indirect interactions in food-webs. Common emergent themes were as follows: OA drives planktonic systems toward the microbial loop, reducing energy transfer to zooplankton and fish; and nutrient/food availability ameliorates negative impacts of OA. We identify several key areas for further research, notably the need for OA-relevant biogeochemical and ecosystem models, and understanding the ecological and evolutionary capacity of Baltic-Skagerrak ecosystems to respond to OA and other anthropogenic drivers.
|
|
| 46. |
- Havenhand, Jonathan N., 1959, et al.
(författare)
-
Försurning i klimatförändringens spår
- 2008
-
Ingår i: HAVET 2008. - Stockholm : Naturvårdsverket. ; , s. 27-30
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 47. |
- Havenhand, Jonathan N., 1959
(författare)
-
How will Ocean Acidification Affect Baltic Sea Ecosystems? An Assessment of Plausible Impacts on Key Functional Groups
- 2012
-
Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 41:6, s. 637-644
-
Tidskriftsartikel (refereegranskat)abstract
- Increasing partial pressure of atmospheric CO2 is causing ocean pH to fall-a process known as 'ocean acidification'. Scenario modeling suggests that ocean acidification in the Baltic Sea may cause a a parts per thousand currency sign3 times increase in acidity (reduction of 0.2-0.4 pH units) by the year 2100. The responses of most Baltic Sea organisms to ocean acidification are poorly understood. Available data suggest that most species and ecologically important groups in the Baltic Sea food web (phytoplankton, zooplankton, macrozoobenthos, cod and sprat) will be robust to the expected changes in pH. These conclusions come from (mostly) single-species and single-factor studies. Determining the emergent effects of ocean acidification on the ecosystem from such studies is problematic, yet very few studies have used multiple stressors and/or multiple trophic levels. There is an urgent need for more data from Baltic Sea populations, particularly from environmentally diverse regions and from controlled mesocosm experiments. In the absence of such information it is difficult to envision the likely effects of future ocean acidification on Baltic Sea species and ecosystems.
|
|
| 48. |
- Havenhand, Jonathan N., 1959, et al.
(författare)
-
Megalodicopia hians in the Monterey submarine canyon: Distribution, larval development, and culture
- 2006
-
Ingår i: Deep-Sea Research Part I-Oceanographic Research Papers. - : Elsevier BV. - 0967-0637. ; 53:2, s. 215-222
-
Tidskriftsartikel (refereegranskat)abstract
- The exclusively deep-sea ascidian family Octacnemidae comprises several genera in which the oral siphon has hypertrophied to form two large lips which create an "oral hood" capable of capturing motile prey. Megalodicopia hians is typical of this carnivorous family and has been reported to prey upon small epibenthic crustaceans. Distribution of M. hians in the Monterey Canyon system (36 degrees 45'N, 122 degrees 00'W) (California) was determined with remotely operated vehicles. M hians was found sparsely to depths of at least 3800m throughout the canyon; however, abundance was greatest within the oxygen-minimum zone (400-800m). Eggs, sperm, and recently fertilized embryos were obtained repeatedly from adults returned to the laboratory in vivo, indicating that this species free-spawns routinely. Overall egg diameter (ovum plus chorion, plus follicle cells) was 175-190 mu m-considerably smaller than previously reported for this species. Embryonic development at temperature and oxygen concentrations equivalent to the oxygen-minimum zone was 2-4d and. embryos gave rise to typical phlebobranch "simple" tadpole larvae. Larval period was extremely variable, and settlement/metamorphosis occurred up to 3 months post-hatching. These results are discussed within the context of settlement-site selection and fertilization ecology of the species. (c) 2005 Elsevier Ltd. All rights reserved.
|
|
| 49. |
|
|
| 50. |
|
|
