| 1. |
- Timmermann, Karen, et al.
(author)
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Modelling macrofaunal biomass in relation to hypoxia and nutrient loading
- 2012
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In: Journal of Marine Systems. - : Elsevier BV. - 0924-7963 .- 1879-1573. ; 105-108, s. 60-69
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Journal article (peer-reviewed)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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| 2. |
- Villnäs, Anna, et al.
(author)
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Changes in macrofaunal biological traits across estuarine gradients : implications for the coastal nutrient filter
- 2019
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In: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 622, s. 31-48
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Journal article (peer-reviewed)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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