| 1. |
- Kotta, Jonne, et al.
(författare)
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Integrating experimental and distribution data to predict future species patterns
- 2019
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Predictive species distribution models are mostly based on statistical dependence between environmental and distributional data and therefore may fail to account for physiological limits and biological interactions that are fundamental when modelling species distributions under future climate conditions. Here, we developed a state-of-the-art method integrating biological theory with survey and experimental data in a way that allows us to explicitly model both physical tolerance limits of species and inherent natural variability in regional conditions and thereby improve the reliability of species distribution predictions under future climate conditions. By using a macroalga-herbivore association (Fucus vesiculosus - Idotea balthica) as a case study, we illustrated how salinity reduction and temperature increase under future climate conditions may significantly reduce the occurrence and biomass of these important coastal species. Moreover, we showed that the reduction of herbivore occurrence is linked to reduction of their host macroalgae. Spatial predictive modelling and experimental biology have been traditionally seen as separate fields but stronger interlinkages between these disciplines can improve species distribution projections under climate change. Experiments enable qualitative prior knowledge to be defined and identify cause-effect relationships, and thereby better foresee alterations in ecosystem structure and functioning under future climate conditions that are not necessarily seen in projections based on non-causal statistical relationships alone.
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| 2. |
- Meysick, L., et al.
(författare)
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Coastal ecosystem engineers and their impact on sediment dynamics: Eelgrass–bivalve interactions under wave exposure
- 2022
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Ingår i: Limnology and Oceanography. - : Wiley. - 1939-5590 .- 0024-3590. ; 67:3, s. 621-633
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Tidskriftsartikel (refereegranskat)abstract
- Habitat forming ecosystem engineers play critical roles in structuring coastal seascapes. Many ecosystem engineers, such as seagrasses and epifaunal bivalves, are known to have positive effects on sediment stability and increase coastal protection and ecosystem resilience. Others, such as bioturbating infaunal bivalves, may instead destabilize sediment. However, despite the common co-occurrence of seagrasses and bivalves in coastal seascapes, little is known of their combined effects on sediment dynamics. Here, we used wave flumes to compare sediment dynamics in monospecific and multispecific treatments of eelgrass, Zostera marina, and associated bivalves (infaunal Limecola balthica, infaunal Cerastoderma edule, epifaunal Magellana gigas) under a range of wave exposures. Eelgrass reduced bedload erosion rates by 25–50%, with digital elevation models indicating that eelgrass affected the sediment micro-bathymetry by decreasing surface roughness and ripple sizes. Effects of bivalves on sediment mobilization were species-specific; L. balthica reduced erosion by 25%, C. edule increased erosion by 40%, while M. gigas had little effect. Importantly, eelgrass modified the impacts of bivalves: the destabilizing effects of C. edule vanished in the presence of eelgrass, while we found positive additive effects of eelgrass and L. balthica on sediment stabilization and potential for mutual anchoring. Such interspecific interactions are likely relevant for habitat patch emergence and resilience to extreme wave conditions. In light of future climate scenarios where increasing storm frequency and wave exposure threaten coastal ecosystems, our results add a mechanistic understanding of sediment dynamics and interactions between ecosystem engineers, with relevance for management and conservation.
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| 3. |
- Milec, Leona, et al.
(författare)
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Double-edged sword of desalination: Decreased growth and increased grazing endanger range-margin Fucus populations
- 2022
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Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981. ; 547
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Tidskriftsartikel (refereegranskat)abstract
- Coastal ecosystems worldwide are facing intense and diverse pressures caused by anthropogenic climate change, which compromises physiological tolerance of organisms, as well as causes shifts in their biotic interactions. Within-species genetic variation plays an important role in persistence of populations under such changes by providing building blocks for adaptation. The brackish-water Baltic Sea is predicted to experience a significant desalination by the end of this century. The Baltic Sea is dominated, in terms of biomass, by a few species with locally adapted populations, making it a suitable model for studying shifting biotic interactions under changing abiotic conditions. We exposed two foundation species of brown algae, Fucus vesiculosus and Fucus radicans, to end-of-the-century projected salinity together with grazing pressure in experimental tanks. We measured growth, grazing and phlorotannin content and compared these traits between the current and projected future salinity conditions, between Fucus species, and between high and low genotypic diversity groups. Grazing, phlorotannin content and growth of both F. radicans and F. vesiculosus all showed genotypic variation. Future decreased salinity hampered growth of F. vesiculosus irrespective of genotypic diversity of the experimental population. Furthermore, the growth response to desalination showed variation among genotypes. F. radicans was more susceptible to grazing than F. vesiculosus, and, in the high genetic diversity group of the latter, grazing was higher in the future than in current salinity. Climate change induced hyposalinity will thus challenge Fucus populations at their range margins in the Baltic Sea both because of the growth deterioration and changes in grazing. Differences between the species in these responses indicate a better ability of F. radicans to cope with the changing environment. Our results emphasize the complexity of biotic interactions in mediating the climate change influences as well as the importance of genetic diversity in coping with climate change.
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| 4. |
- Rothäusler, Eva, et al.
(författare)
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It takes two to stay afloat: interplay of morphology and physiological acclimation ensures long-term floating dispersal of the bladderwrack Fucus vesiculosus (Phaeophyceae, Fucales)
- 2020
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Ingår i: European Journal of Phycology. - : Informa UK Limited. - 0967-0262 .- 1469-4433. ; 55:2, s. 242-252
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Tidskriftsartikel (refereegranskat)abstract
- © 2020, © 2020 British Phycological Society. Floating algae can be found in high abundances at mid and high latitudes, their prolonged positive buoyancy allowing long-distance dispersal. However, despite their importance to dispersal and ecological and evolutionary meta-population dynamics, little is known about the buoyancy responses of high latitude algae to the conditions at the sea surface. Indeed, even at 60°N environmental conditions during spring/summer can be challenging, and may cause the demise and sinking of floating algae. The bladderwrack Fucus vesiculosus from the Northern Baltic Sea floats on the sea surface when detached from the benthic substratum. We conducted a field experiment with tethered individuals during their reproductive period to measure variation in floating time and how that is related to morphological traits such as occurrence of vesicles and/or receptacles, and to measure growth and photosynthesis while afloat. Algal individuals with receptacles tended to sink quickly, whereas the longest floating time was evident for individuals carrying vesicles but lacking receptacles. While afloat, all individuals grew in size, showed photosynthetic acclimation to sea surface conditions and had a few invertebrates associated with them. Our results showed that rafts of F. vesiculosus were physiologically viable until their day of sinking and that morphological traits such as the occurrence of vesicles and receptacles modified their floating time. Accordingly, floating algae with a similar morphological set-up, and thus also reproductive phenology, to F. vesiculosus can have a high floating persistence, but, depending on their reproductive structures, they may mostly serve as long-range dispersal vehicles for associated organisms.
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| 5. |
- Rugiu, Luca, et al.
(författare)
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Climate change driven hyposalinity as a selective agent in the littoral mesoherbivore Idotea balthica
- 2021
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Ingår i: Marine Environmental Research. - : Elsevier BV. - 0141-1136 .- 1879-0291. ; 163
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Tidskriftsartikel (refereegranskat)abstract
- © 2020 Elsevier Ltd Climate change will include a decrease in seawater salinity in the Baltic Sea. We quantified the effects of the projected future desalination on survival of the early life stage of the littoral herbivore Idotea balthica. We collected egg-bearing Idotea from three range-margin Baltic Sea populations, we exposed half of each brood to either current (6‰) or future salinity (3.5‰). We genotyped a subsample of each brood to analyse patterns of allelic change and to identify genomic regions targeted by selection. The survival was overall reduced by hyposalinity and broods varied in response to hyposalinity implying genetic variation in tolerance, with a stronger decrease in genetic diversity in future salinity. Finally, we identified proteins with crucial roles in basic cellular functions. This study indicates that projected future northern Baltic Sea hyposalinity will not just hamper I. balthica survival, but its selective pressure may also affect genetic diversity and cell physiology.
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| 6. |
- Rugiu, Luca, et al.
(författare)
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Gene regulatory response to hyposalinity in the brown seaweed Fucus vesiculosus
- 2020
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Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Rockweeds are among the most important foundation species of temperate rocky littoral shores. In the Baltic Sea, the rockweed Fucus vesiculosus is distributed along a decreasing salinity gradient from the North Atlantic entrance to the low-salinity regions in the north-eastern margins, thus, demonstrating a remarkable tolerance to hyposalinity. The underlying mechanisms for this tolerance are still poorly understood. Here, we exposed F. vesiculosus from two range-margin populations to the hyposaline (2.5 PSU - practical salinity unit) conditions that are projected to occur in the region by the end of this century as a result of climate change. We used transcriptome analysis (RNA-seq) to determine the gene expression patterns associated with hyposalinity acclimation, and examined the variation in these patterns between the sampled populations. Results Hyposalinity induced different responses in the two populations: in one, only 26 genes were differentially expressed between salinity treatments, while the other population demonstrated up- or downregulation in 3072 genes. In the latter population, the projected future hyposalinity induced an acute response in terms of antioxidant production. Genes associated with membrane composition and structure were also heavily involved, with the upregulation of fatty acid and actin production, and the downregulation of ion channels and alginate pathways. Changes in gene expression patterns clearly indicated an inhibition of the photosynthetic machinery, with a consequent downregulation of carbohydrate production. Simultaneously, energy consumption increased, as revealed by the upregulation of genes associated with respiration and ATP synthesis. Overall, the genes that demonstrated the largest increase in expression were ribosomal proteins involved in translation pathways. The fixation rate of SNP:s was higher within genes responding to hyposalinity than elsewhere in the transcriptome. Conclusions The high fixation rate in the genes coding for salinity acclimation mechanisms implies strong selection for them. The among-population differentiation that we observed in the transcriptomic response to hyposalinity stress suggests that populations of F. vesiculosus may differ in their tolerance to future desalination, possibly as a result of local adaptation to salinity conditions within the Baltic Sea. These results emphasise the importance of considering interspecific genetic variation when evaluating the consequences of environmental change.
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| 7. |
- Rugiu, Luca, et al.
(författare)
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Kelp in IMTAs: small variations in inorganic nitrogen concentrations drive different physiological responses of Saccharina latissima
- 2021
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Ingår i: Journal of Applied Phycology. - : Springer Science and Business Media LLC. - 0921-8971 .- 1573-5176. ; 33, s. 1021-1034
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Tidskriftsartikel (refereegranskat)abstract
- © 2020, The Author(s). Kelps can be included in integrated multitrophic aquaculture (IMTA) where their growth and quality might benefit from the nutrient load released by other species like finfish and mussels transforming effluents from the cultured animals into valuable products. We studied how different nutrient concentrations affect growth, photosynthesis, chemical composition and pigment content of the kelp Saccharina latissima. We exposed kelps to natural seawater, water enriched to levels of ammonium and nitrate simulating finfish cage waste (IMTA1) and a combination of such enrichment with natural effluents coming from mussels (IMTA2). The algal biomass was higher and produced elevated total organic content when exposed to both IMTA1 and IMTA2. The photosynthetic responses in terms of relative electron transfer rate (rETRmax), PSII saturation irradiance (Ek) and total nitrogen content were also positively affected by both IMTA1 and IMTA2. We found a significant enhancement in pigment content only when algae were exposed to the strongest enrichment of our study (IMTA2). Finally, we found a positive relationship between rETRmax and growth, and the content of chlorophyll a and fucoxanthin. Our results show significant physiological responses of S. latissima to nutrient enrichment mimicking IMTA settings, as well as the benefit of added nutrients through a boost in photosynthetic activity that leads to higher kelp biomass and pigment production. This study suggests that modest nitrogen enrichment such as the one in our IMTA2 setup is enough to generate not only higher kelp biomass, but also an increased biomass quality with potentially higher market value.
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