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Publications (10 of 30) Show all publications
Gustafsson, E., Winder, M. & Dupont, S. (2024). Havsförsurning ytterligare etthot mot Östersjöns ekosystem. Stockholm: Stockholm University
Open this publication in new window or tab >>Havsförsurning ytterligare etthot mot Östersjöns ekosystem
2024 (Swedish)Other, Policy document (Other (popular science, discussion, etc.))
Abstract [sv]

Havsförsurningen väntas de kommande decennierna bli påtaglig även i Östersjön. För det redan hårt pressade ekosystemet innebär det ytterligare en belastning. Den samlade effekten av försurningen och annan miljöpåverkan kan stressa arter och minska den biologiska mångfalden. För att skydda den unika miljön och den framtida matproduktionen krävs både kraftigt minskade koldioxidutsläpp och åtgärder mot övergödning, överfiske och utsläpp av farliga ämnen.

Place, publisher, year, pages
Stockholm: Stockholm University, 2024. p. 4
Series
Policy briefs från Stockholms universitets Östersjöcentrum
Keywords
Försurning, hav, Östersjön, ekosystem
National Category
Oceanography, Hydrology and Water Resources
Research subject
Biogeochemistry; Oceanography; Marine Ecology
Identifiers
urn:nbn:se:su:diva-226352 (URN)
Available from: 2024-02-07 Created: 2024-02-07 Last updated: 2024-02-09Bibliographically approved
Gustafsson, E., Winder, M. & Dupont, S. (2024). Ocean acidification poses another threat to the Baltic Sea ecosystem. Stockholm: Stockholm University
Open this publication in new window or tab >>Ocean acidification poses another threat to the Baltic Sea ecosystem
2024 (English)Other, Policy document (Other (popular science, discussion, etc.))
Abstract [en]

In the coming decades, ocean acidification is expected to become significant also in the Baltic Sea. For an already stressed ecosystem, it represents an additional pressure, and the cumulative effect of this and other environmental impacts can stress species and reduce biodiversity. Protecting the unique environment and future food production requires both significant reductions in carbon dioxide emissions and measures against eutrophication, overfishing and emissions of hazardous substances.

Abstract [sv]

Havsförsurningen väntas de kommande decennierna bli påtaglig även i Östersjön. För det redan hårt pressade ekosystemet innebär det ytterligare en belastning. Den samlade effekten av försurningen och annan miljöpåverkan kan stressa arter och minska den biologiska mångfalden. För att skydda den unika miljön och den framtida matproduktionen krävs både kraftigt minskade koldioxidutsläpp och åtgärder mot övergödning, överfiske och utsläpp av farliga ämnen.

Place, publisher, year, pages
Stockholm: Stockholm University, 2024. p. 4
Series
Policy briefs från Stockholms universitets Östersjöcentrum
Keywords
Policy brief, acidification, baltic sea, climate change
National Category
Oceanography, Hydrology and Water Resources
Research subject
Biogeochemistry; Oceanography; Marine Ecology
Identifiers
urn:nbn:se:su:diva-226349 (URN)
Available from: 2024-02-07 Created: 2024-02-07 Last updated: 2024-02-09Bibliographically approved
Gustafsson, E., Carstensen, J., Fleming, V., Gustafsson, B. G., Hoikkala, L. & Rehder, G. (2023). Causes and consequences of acidification in the Baltic Sea: implications for monitoring and management. Scientific Reports, 13, Article ID 16322.
Open this publication in new window or tab >>Causes and consequences of acidification in the Baltic Sea: implications for monitoring and management
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2023 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 13, article id 16322Article in journal (Refereed) Published
Abstract [en]

Increasing atmospheric CO2 drives ocean acidification globally. In coastal seas, acidification trends can however be either counteracted or enhanced by other processes. Ecosystem effects of acidification are so far small in the Baltic Sea, but changes should be anticipated unless CO2 emissions are curbed. Possible future acidification trends in the Baltic Sea, conditional on CO2 emissions, climate change, and changes in productivity, can be assessed by means of model simulations. There are uncertainties regarding potential consequences for marine organisms, partly because of difficulties to assign critical thresholds, but also because of knowledge gaps regarding species’ capacity to adapt. Increased temporal and spatial monitoring of inorganic carbon system parameters would allow a better understanding of current acidification trends and also improve the capacity to predict possible future changes. An additional benefit is that such measurements also provide quantitative estimates of productivity. The technology required for precise measurements of the inorganic carbon system is readily available today. Regularly updated status evaluations of acidification, and the inorganic carbon system in general, would support management when assessing climate change effects, eutrophication or characteristics of the pelagic habitats. This would, however, have to be based on a spatially and temporally sufficient monitoring program.

National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:su:diva-222985 (URN)10.1038/s41598-023-43596-8 (DOI)001138089300001 ()2-s2.0-85173094289 (Scopus ID)
Available from: 2023-10-30 Created: 2023-10-30 Last updated: 2024-02-13Bibliographically approved
Gustafsson, E. & Humborg, C. (2023). Policy brief: Minskad övergödning avgörande för att hindra kustnära metanutsläpp. Stockholm: Stockholm University
Open this publication in new window or tab >>Policy brief: Minskad övergödning avgörande för att hindra kustnära metanutsläpp
2023 (Swedish)Other, Policy document (Other (popular science, discussion, etc.))
Abstract [sv]

En stor del av de mänskligt orsakade utsläppen av koldioxid har tagits upp av haven. Men många av de svenska kusterna är idag påverkade av övergödning, vilket gör dem till en källa till växthusgaser, främst i form av metan. Att minska övergödningen är avgörande för att begränsa metanutsläppen och därmed motverka klimatförändringarna.

Place, publisher, year, pages
Stockholm: Stockholm University, 2023. p. 4
Keywords
Övergödning, växthusgaser, metan, kust, hav, klimatförändring
National Category
Climate Research Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:su:diva-224760 (URN)
Available from: 2023-12-21 Created: 2023-12-21 Last updated: 2024-02-07Bibliographically approved
Gustafsson, E., Gustafsson, B., Carstensen, J., Rehder, G. & Fleming, V. (2021). OMAI – Assessing acidification in the Baltic Sea, monitoring and scientific basis. Copenhagen: Nordisk Ministerråd
Open this publication in new window or tab >>OMAI – Assessing acidification in the Baltic Sea, monitoring and scientific basis
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2021 (English)Report (Other academic)
Abstract [en]

In marine and brackish waters, the acidity of the water is mainly controlled by the inorganic carbon system. Anthropogenic CO2 emissions will – unless reduced – gradually move the Baltic Sea towards a state where acidification becomes harmful for some organisms. The effect is caused by the uptake of CO2 in the water, but can be further enhanced by other climate effects, such as increased water temperature and a possible freshening of the sea water. This is expected to lead to changes in species composition, both directly (competitive advantages/disadvantages) and indirectly (altered food availability), potentially influencing ecosystem functioning.

Coastal seas, such as the Baltic Sea, are highly influenced by their catchment areas, which means that pH dynamics is generally more complex than in the open ocean. The reason is that pH, in addition to the response to increasing CO2, is also influenced by changes in hydrology and changes in the supply of carbon and nutrients. High-productive waters typically experience larger seasonal pH variations than low-productive waters, with higher pH peaks in spring/summer and also a more pronounced pH decline in winter. The comparatively weak long-term acidification trend can be masked behind much larger short-term variations. Furthermore, since acidification is a slow process, organisms can to varying degrees adapt to the changes.

Model simulations performed as a part of the OMAI (Operational Marine Acidification Indicator) project indicate that the expected acidification in the Baltic Sea generally follows the same trajectory as the open oceans, with a pH decline of almost 0.4 by year 2100 and a further decline of 0.3 by year 2300 in the worst-case scenario. Due to large regional differences in the area, the annual mean pH in the Bothnian Bay might decline from present-day 7.8 to 7.4 by year 2100, whereas in the Gotland Sea and Southern Kattegat mean pH could decline from present-day 8.1 to 7.7. The degree of eutrophication has a comparatively small effect on the annual mean pH, but on the other hand a considerable impact on the seasonal amplitude and thus minimum and maximum values.

The complex situation in the Baltic Sea gives a strong incentive to improve the temporal and spatial coverage of acidification monitoring. This would broaden the understanding of current acidification trends and also improve the capacity to predict future changes. An indicator for acidification in the Baltic Sea is currently under development. Monitoring of parameters relevant for acidification, i.e., the inorganic carbon system parameters, would as an added value also provide an additional handle in terms of assessing changes in primary production and eutrophication trends.

Place, publisher, year, edition, pages
Copenhagen: Nordisk Ministerråd, 2021. p. 25
Series
TemaNord, ISSN 0908-6692 ; 2021:512
National Category
Oceanography, Hydrology and Water Resources
Research subject
Oceanography
Identifiers
urn:nbn:se:su:diva-203194 (URN)10.6027/temanord2021-512 (DOI)978-92-893-6981-7 (ISBN)978-92-893-6980-0 (ISBN)
Funder
Nordic Council of Ministers, 190009
Available from: 2022-03-24 Created: 2022-03-24 Last updated: 2022-03-25Bibliographically approved
Gustafsson, E. & Gustafsson, B. G. (2020). Future acidification of the Baltic Sea - A sensitivity study. Journal of Marine Systems, 211, Article ID 103397.
Open this publication in new window or tab >>Future acidification of the Baltic Sea - A sensitivity study
2020 (English)In: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 211, article id 103397Article in journal (Refereed) Published
Abstract [en]

Future acidification of coastal seas will depend not only on the development of atmospheric CO2 partial pressure (pCO(2)), but also on changes in the catchment areas, exchange with the adjacent ocean, and internal cycling of carbon and nutrients. Here we use a coupled physical-biogeochemical Baltic Sea model to quantify the sensitivity of pH to changes both in external forcing and internal processes. The experiments include changes in runoff, supply of dissolved inorganic carbon (DIC) and total alkalinity (A(T)), nutrient loads, exchange between the Baltic and North Seas, and atmospheric pCO(2). We furthermore address the potential different future developments of runoff and river loads in boreal and continental catchments, respectively. Changes in atmospheric pCO(2) exert the strongest control on future pH according to our calculations. This CO2-induced acidification could be further enhanced in the case of desalination of the Baltic Sea, although increased concentrations of A(T) in the river runoff due to increased weathering to some extent could counteract acidification. Reduced nutrient loads and productivity would reduce the average annual surface water pH but at the same time slightly increase wintertime surface water pH (the annual pH minimum). The response time of surface water pH to sudden changes in atmospheric pCO(2) is approximately one month, whereas response times to changes in e.g. runoff and A(T)/DIC loads are more related to residence times of water and salt (> 30 years). It seems unlikely that the projected future increase in atmospheric pCO(2) and associated pH reduction could be fully counteracted by any of the other processes addressed in our experiments.

Keywords
Marine carbonate system, Physical-biogeochemical modelling, Sensitivity experiments, Baltic Sea
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-186129 (URN)10.1016/j.jmarsys.2020.103397 (DOI)000567819700006 ()
Available from: 2020-11-23 Created: 2020-11-23 Last updated: 2022-02-25Bibliographically approved
Ehrnsten, E., Norkko, A., Müller‐Karulis, B., Gustafsson, E. & Gustafsson, B. G. (2020). The meagre future of benthic fauna in a coastal sea-Benthic responses to recovery from eutrophication in a changing climate. Global Change Biology, 26(4), 2235-2250
Open this publication in new window or tab >>The meagre future of benthic fauna in a coastal sea-Benthic responses to recovery from eutrophication in a changing climate
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2020 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 26, no 4, p. 2235-2250Article in journal (Refereed) Published
Abstract [en]

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.

Keywords
Baltic Sea, benthic macrofauna, carbon cycle, climate change, eutrophication, numerical model, oligotrophication
National Category
Biological Sciences Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-180412 (URN)10.1111/gcb.15014 (DOI)000513939900001 ()31986234 (PubMedID)
Available from: 2020-03-30 Created: 2020-03-30 Last updated: 2022-03-23Bibliographically approved
Meier, H. E., Edman, M., Eilola, K., Placke, M., Neumann, T., Andersson, H. C., . . . Savchuk, O. P. (2019). Assessment of Uncertainties in Scenario Simulations of Biogeochemical Cycles in the Baltic Sea. Frontiers in Marine Science, 6, Article ID 46.
Open this publication in new window or tab >>Assessment of Uncertainties in Scenario Simulations of Biogeochemical Cycles in the Baltic Sea
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2019 (English)In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 6, article id 46Article, review/survey (Refereed) Published
Abstract [en]

Following earlier regional assessment studies, such as the Assessment of Climate Change for the Baltic Sea Basin and the North Sea Region Climate Change Assessment, knowledge acquired from available literature about future scenario simulations of biogeochemical cycles in the Baltic Sea and their uncertainties is assessed. The identification and reduction of uncertainties of scenario simulations are issues for marine management. For instance, it is important to know whether nutrient load abatement will meet its objectives of restored water quality status in future climate or whether additional measures are required. However, uncertainties are large and their sources need to be understood to draw conclusions about the effectiveness of measures. The assessment of sources of uncertainties in projections of biogeochemical cycles based on authors' own expert judgment suggests that the biggest uncertainties are caused by (1) unknown current and future bioavailable nutrient loads from land and atmosphere, (2) the experimental setup (including the spin up strategy), (3) differences between the projections of global and regional climate models, in particular, with respect to the global mean sea level rise and regional water cycle, (4) differing model-specific responses of the simulated biogeochemical cycles to long-term changes in external nutrient loads and climate of the Baltic Sea region, and (5) unknown future greenhouse gas emissions. Regular assessments of the models' skill (or quality compared to observations) for the Baltic Sea region and the spread in scenario simulations (differences among projected changes) as well as improvement of dynamical downscaling methods are recommended.

Keywords
Baltic Sea, nutrients, eutrophication, climate change, future projections, uncertainties, ensemble simulations
National Category
Earth and Related Environmental Sciences Biological Sciences
Identifiers
urn:nbn:se:su:diva-168293 (URN)10.3389/fmars.2019.00046 (DOI)000462709300001 ()
Available from: 2019-04-30 Created: 2019-04-30 Last updated: 2022-03-23Bibliographically approved
Bayer, T. K., Gustafsson, E., Brakebusch, M. & Beer, C. (2019). Future Carbon Emission From Boreal and Permafrost Lakes Are Sensitive to Catchment Organic Carbon Loads. Journal of Geophysical Research - Biogeosciences, 124(7), 1827-1848
Open this publication in new window or tab >>Future Carbon Emission From Boreal and Permafrost Lakes Are Sensitive to Catchment Organic Carbon Loads
2019 (English)In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 124, no 7, p. 1827-1848Article in journal (Refereed) Published
Abstract [en]

Carbon storage, processing, and transport in freshwater systems are important components of the global carbon cycle and sensitive to global change. However, in large-scale modeling this part of the boundless carbon cycle is often lacking or represented in a very simplified way. A new process-oriented lake biogeochemical model is used for investigating impacts of changes in atmospheric CO2 concentrations and organic carbon loading from the catchment on future greenhouse gas emissions from lakes across two boreal to subarctic regions (Northern Sweden and Alaska). Aquatic processes represented include carbon, oxygen, phytoplankton, and nutrient dynamics leading to CO2 and CH4 exchanges with the atmosphere. The model is running inside a macroscale hydrological model and may be easily implemented into a land surface scheme. Model evaluation demonstrates the validity in terms of average concentration of nutrients, algal biomass, and organic and inorganic carbon. Cumulative annual emissions of CH4 and CO2, as well as pathways of CH4 emissions, also compare well to observations. Model calculations imply that lake emissions of CH4 may increase by up to 45% under the Representative Concentration Pathway 8.5 scenario until 2100, and CO2 emissions may increase by up to 80% in Alaska. Increasing organic carbon loading to the lakes resulted in a linear response in CO2 and CH4 emissions across both regions, but increases in CO2 emissions from subarctic lakes in Sweden were lower than for southern boreal lakes, probably due to the higher importance of imported vegetation-generated inorganic carbon for CO2 emission from subarctic lakes.

Keywords
lake, biogeochemistry, methane, carbon cycle, climate change, freshwater
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-173042 (URN)10.1029/2018JG004978 (DOI)000481443800006 ()
Available from: 2019-09-27 Created: 2019-09-27 Last updated: 2022-03-23Bibliographically approved
Hermans, M., K. Lenstra, W., van Helmond, N. A. G., Behrends, T., Egger, M., Séguret, M. J. M., . . . Slomp, C. P. (2019). Impact of natural re-oxygenation on the sediment dynamics of manganese, iron and phosphorus in a euxinic Baltic Sea basin. Geochimica et Cosmochimica Acta, 246, 174-196
Open this publication in new window or tab >>Impact of natural re-oxygenation on the sediment dynamics of manganese, iron and phosphorus in a euxinic Baltic Sea basin
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2019 (English)In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 246, p. 174-196Article in journal (Refereed) Published
Abstract [en]

The Baltic Sea is characterized by the largest area of hypoxic (oxygen (O2) < 2 mg L−1) bottom waters in the world’s ocean induced by human activities. Natural ventilation of these O2-depleted waters largely depends on episodic Major Baltic Inflows from the adjacent North Sea. In 2014 and 2015, two such inflows led to a strong rise in O2 and decline in phosphate (HPO42−) in waters below 125 m depth in the Eastern Gotland Basin. This provided the opportunity to assess the impact of such re-oxygenation events on the cycles of manganese (Mn), iron (Fe) and phosphorus (P) in the sediment for the first time. We demonstrate that the re-oxygenation induced the activity of sulphur (S)-oxidising bacteria, known as Beggiatoaceae in the surface sediment where a thin oxic and suboxic layer developed. At the two deepest sites, strong enrichments of total Mn and to a lesser extent Fe oxides and P were observed in this surface layer. A combination of sequential sediment extractions and synchrotron-based X-ray spectroscopy revealed evidence for the abundant presence of P-bearing rhodochrosite and Mn(II) phosphates. In contrast to what is typically assumed, the formation of Fe oxides in the surface sediment was limited. We attribute this lack of Fe oxide formation to the high flux of reductants, such as sulphide, from deeper sediments which allows Fe(II) in the form of FeS to be preserved and restricts the penetration of O2 into the sediment. We estimate that enhanced P sequestration in surface sediments accounts for only ∼5% of water column HPO42− removal in the Eastern Gotland Basin linked to the recent inflows. The remaining HPO42− was transported to adjacent areas in the Baltic Sea. Our results highlight that the benthic O2 demand arising from the accumulation of organic-rich sediments over several decades, the legacy of hypoxia, has major implications for the biogeochemical response of euxinic basins to re-oxygenation. In particular, P sequestration in the sediment in association with Fe oxides is limited. This implies that artificial ventilation projects that aim at removing water column HPO42− and thereby improving water quality in the Baltic Sea will likely not have the desired effect.

Keywords
Manganese, Iron, Phosphorus, Re-oxygenation, Baltic Sea, Major Baltic Inflow
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-164513 (URN)10.1016/j.gca.2018.11.033 (DOI)000455651400010 ()
Available from: 2019-01-16 Created: 2019-01-16 Last updated: 2022-02-26Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4215-9322

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