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Eva Ehrnsten, foto: Niklas Björling/SU

Eva Ehrnsten

postdoktor

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Arbetar vid Stockholms universitets Östersjöcentrum
E-post eva.ehrnsten@su.se
Besöksadress Svante Arrhenius väg 20 F, plan 5
Postadress Stockholms universitets Östersjöcentrum 106 91 Stockholm

Om mig

My main research interests are coastal ecology and management. My postdoctoral research focusses on simulating ecosystem dynamics of the Baltic Sea and the role of benthic fauna in biogeochemical cycling. I also study how the joint effects of climate change and human-induced pressures such as nutrient loads might change the functioning of benthic and pelagic ecosystems.

I did my PhD on past, present and future biomass and carbon processing of benthic fauna jointly in the Benthic Ecology Team at Tvärminne Zoological Station, University of Helsinki and the Baltic Sea Centre, Stockholm University. Previously I have worked with mapping underwater nature and management of coastal habitats (VELMU and NANNUT projects), minimizing the ecological effects of oil spills in coastal areas (OILRISK project) and intedisciplinary approaches to study marine ecosystem services (BALTICAPP project).

Publikationer

I urval från Stockholms universitets publikationsdatabas
  • 2020. Eva Ehrnsten (et al.). Global Change Biology 26 (4), 2235-2250

    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.

  • 2019. Eva Ehrnsten, Barbara Bauer, Bo G. Gustafsson. Frontiers in Marine Science 6

    The responses of food webs to simultaneous changes in several environmental drivers are still poorly understood. As a contribution to filling this knowledge gap, we investigated the major pathways through which two interlinked environmental drivers, eutrophication and climate, affect the biomass and community composition of fish and benthic macrofauna. For this aim, we conducted a systematic sensitivity analysis using two models simulating the dynamics of benthic and pelagic food webs in the Baltic Sea. We varied environmental forcing representing primary productivity, oxygen conditions and water temperature in all possible combinations, over a range representative of expected changes during the 21st century. Both models indicated that increased primary productivity leads to biomass increase in all parts of the system, however, counteracted by expanding hypoxia. Effects of temperature were complex, but generally small compared to the other drivers. Similarities across models give confidence in the main results, but we also found differences due to different representations of the food web in the two models. While both models predicted a shift in benthic community composition toward an increased abundance of Limecola (Macoma) balthica with increasing productivity, the effects on deposit-feeding and predatory benthic groups depended on the presence of fish predators in the model. The model results indicate that nutrient loads are a stronger driver of change for ecosystem functions in the Baltic Sea than climate change, but it is important to consider the combined effects of these drivers for proper management of the marine environment.

Visa alla publikationer av Eva Ehrnsten vid Stockholms universitet

Senast uppdaterad: 25 juni 2020

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