Past, current, and future freshwater inflows to the Baltic Sea under changing climate and socioeconomics

2020 ◽  
Author(s):  
Alena Bartosova ◽  
René Capell ◽  
Jørgen E. Olesen ◽  
Berit Arheimer
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Large Scale ◽  
Mitigation Measures ◽  
Nutrient Loads ◽  
Socioeconomic Conditions ◽  
The Baltic Sea ◽  
Nitrogen Loads ◽  
The Baltic ◽  
Freshwater Inflows

<p>The Baltic Sea is suffering from eutrophication caused by nutrient discharges from land to sea. These freshwater inflows vary in magnitude from year to year as well as within each year due to e.g. natural variability, weather patterns, and seasonal human activities. Nutrient transport models are important tools for assessments of macro-nutrient fluxes (nitrogen, phosphorus) and for evaluating the connection between pollution sources and the assessed water body. While understanding of current status is important, impacts from changing climate and socio-economics on freshwater inflows to the Baltic Sea also need to be taken into account when planning management practices and mitigation measures.</p><p>Continental to global scale catchment-based hydrological models have emerged in recent years as tools e.g. for flood forecasting, large-scale climate impact analyses, and estimation of time-dynamic water fluxes into sea basins. Here, we present results from the pan-European rainfall-runoff and nutrient transfer model E-HYPE, developed as a multi-purpose tool for large-scale hydrological analyses. We compared current freshwater inflows from land with those from dynamic modelling with E-HYPE under various climate and socioeconomic conditions. The socioeconomic conditions (land use, agricultural practices, population changes, dietary changes, atmospheric deposition, and wastewater technologies) were evaluated for 3 additional time horizons: 2050s using the Shared Socioeconomic Pathways, 1900s using historical data, and a reference period using a synthetic “no human impact” scenario. An ensemble of 4 climate models that preserves the range of projected changes in precipitation and temperature from a larger ensemble was selected for analysis of climate impacts in 2050s.  </p><p>We show that while climate change affects nutrient loads to the Baltic Sea, these impacts can be overshadowed by the impacts of changing socioeconomic factors. Historical nitrogen loads were estimated as 43% and 33% of the current loads for the 1900s and the “no human impact” scenarios, respectively. Average nitrogen loads are projected to increase by 4-10% (8% on average) as a response to climate change by 2050s. Purely mitigation measures that did not address the magnitude of the nutrient sources reduced the total nitrogen load by <5%, with local efficiencies being reduced through retention processes. However, changes in the socioeconomic drivers led to significant changes in the future loads with the range of impacts spanning 30% of the current load depending on the socioeconomic pathway to be followed. This means that policy decisions have by far the largest impact when managing eutrophication in the Baltic Sea region.</p><p>Bartosova, A., Capell, R., Olesen, J.E. et al. (2019). Future socioeconomic conditions may have a larger impact than climate change on nutrient loads to the Baltic Sea. Ambio 48, 1325–1336 doi:10.1007/s13280-019-01243-5</p>

scholarly journals Future socioeconomic conditions may have a larger impact than climate change on nutrient loads to the Baltic Sea

AMBIO ◽  
2019 ◽  
Vol 48 (11) ◽  
pp. 1325-1336 ◽  
Author(s):  
Alena Bartosova ◽  
René Capell ◽  
Jørgen E. Olesen ◽  
Mohamed Jabloun ◽  
Jens Christian Refsgaard ◽  
...  
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Dynamic Modelling ◽  
Climate Change Scenarios ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
Nitrogen And Phosphorus ◽  
Socioeconomic Drivers ◽  
The Baltic ◽  
The Impact

Abstract The Baltic Sea is suffering from eutrophication caused by nutrient discharges from land to sea, and these loads might change in a changing climate. We show that the impact from climate change by mid-century is probably less than the direct impact of changing socioeconomic factors such as land use, agricultural practices, atmospheric deposition, and wastewater emissions. We compare results from dynamic modelling of nutrient loads to the Baltic Sea under projections of climate change and scenarios for shared socioeconomic pathways. Average nutrient loads are projected to increase by 8% and 14% for nitrogen and phosphorus, respectively, in response to climate change scenarios. In contrast, changes in the socioeconomic drivers can lead to a decrease of 13% and 6% or an increase of 11% and 9% in nitrogen and phosphorus loads, respectively, depending on the pathway. This indicates that policy decisions still play a major role in climate adaptation and in managing eutrophication in the Baltic Sea region.

A combination of species distribution and ocean-biogeochemical models suggests that climate change overrides eutrophication as the driver of future distributions of a key benthic crustacean in the estuarine ecosystem of the Baltic Sea

2020 ◽  
Vol 77 (6) ◽  
pp. 2089-2105
Author(s):  
Mayya Gogina ◽  
Michael L Zettler ◽  
Irene Wåhlström ◽  
Helén Andersson ◽  
Hagen Radtke ◽  
...  
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Action Plan ◽  
Future Climate Change ◽  
Suitable Habitat ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
Estuarine Ecosystem ◽  
Biogeochemical Models ◽  
The Baltic

Abstract Species in the brackish and estuarine ecosystems will experience multiple changes in hydrographic variables due to ongoing climate change and nutrient loads. Here, we investigate how a glacial relict species (Saduria entomon), having relatively cold, low salinity biogeographic origin, could be affected by the combined scenarios of climate change and eutrophication. It is an important prey for higher trophic-level species such as cod, and a predator of other benthic animals. We constructed habitat distribution models based occurrence and density of this species across the entire Baltic and estimated the relative importance of different driving variables. We then used two regional coupled ocean-biogeochemical models to investigate the combined impacts of two future climate change and nutrient loads scenarios on its spatial distribution in 2070–2100. According to the scenarios, the Baltic Sea will become warmer and fresher. Our results show that expected changes in salinity and temperature outrank those due to two nutrient-load scenarios (Baltic Sea Action Plan and business as usual) in their effect on S. entomon distribution. The results are relatively similar when using different models with the same scenarios, thereby increasing the confidence of projections. Overall, our models predict a net increase (and local declines) of suitable habitat area, total abundance and biomass for this species, which is probably facilitated by strong osmoregulation ability and tolerance to temperature changes. We emphasize the necessity of considering multiple hydrographic variables when estimating climate change impacts on species living in brackish and estuarine systems.

Climate change and recovery from eutrophication reduce benthic fauna and carbon processing in a coastal sea

2020 ◽  
Author(s):  
Eva Ehrnsten ◽  
Alf Norkko ◽  
Bärbel Müller-Karulis ◽  
Erik Gustafsson ◽  
Bo Gustafsson
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Coastal Ecosystems ◽  
Benthic Macrofauna ◽  
Combined Effects ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
The Future ◽  
The Baltic ◽  
Carbon Processing

<p>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 the physical-biogeochemical BALTSEM 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-21<sup>st</sup> century but then decreased, giving almost no net change by the end of the 21<sup>st</sup> 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.</p>

scholarly journals Climatic variation in Africa and Europe has combined effects on timing of spring migration in a long-distance migrant Willow Warbler Phylloscopus trochilus

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8770
Author(s):  
Magdalena Remisiewicz ◽  
Les G. Underhill
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Large Scale ◽  
Spring Migration ◽  
Climate Indices ◽  
The Baltic Sea ◽  
Willow Warbler ◽  
Long Distance ◽  
The Baltic ◽  
Sea Coast

Background The arrival of many species of migrant passerine in the European spring has shifted earlier over recent decades, attributed to climate change and rising temperatures in Europe and west Africa. Few studies have shown the effects of climate change in both hemispheres though many long-distance migrants use wintering grounds which span Africa. The migrants’ arrival in Europe thus potentially reflects a combination of the conditions they experience across Africa. We examine if the timing of spring migration of a long-distance migrant, the Willow Warbler, is related to large-scale climate indices across Africa and Europe. Methods Using data from daily mistnetting from 1 April to 15 May in 1982–2017 at Bukowo (Poland, Baltic Sea coast), we developed an Annual Anomaly metric (AA, in days) to estimate how early or late Willow Warblers arrive each spring in relation to their multi-year average pattern. The Willow Warblers’ spring passage advanced by 5.4 days over the 36 years. We modelled AA using 14 potential explanatory variables in multiple regression models. The variables were the calendar year and 13 large-scale indices of climate in Africa and Europe averaged over biologically meaningful periods of two to four months during the year before spring migration. Results The best model explained 59% of the variation in AA with seven variables: Northern Atlantic Oscillation (two periods), Indian Ocean Dipole, Southern Oscillation Index, Sahel Precipitation Anomaly, Scandinavian Index and local mean temperatures. The study also confirmed that a long-term trend for Willow Warblers to arrive earlier in spring continued up to 2017. Discussion Our results suggest that the timing of Willow Warbler spring migration at the Baltic Sea coast is related to a summation of the ecological conditions they had encountered over the previous year during breeding, migration south, wintering in Africa and migration north. We suggest these large-scale climate indices reflect ecological drivers for phenological changes in species with complex migration patterns and discuss the ways in which each of the seven climate indices could be related to spring migration at the Baltic Sea coast.

scholarly journals Remediating Agricultural Legacy Nutrient Loads in the Baltic Sea Region

2021 ◽  
Vol 13 (7) ◽  
pp. 3872
Author(s):  
Julia Tanzer ◽  
Ralf Hermann ◽  
Ludwig Hermann
Keyword(s):  
Baltic Sea ◽  
Agricultural Soils ◽  
Economic Benefits ◽  
Current Data ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
Nutrient Emissions ◽  
Long Run ◽  
The Baltic ◽  
Agricultural Legacy

The Baltic Sea is considered the marine water body most severely affected by eutrophication within Europe. Due to its limited water exchange nutrients have a particularly long residence time in the sea. While several studies have analysed the costs of reducing current nutrient emissions, the costs for remediating legacy nutrient loads of past emissions remain unknown. Although the Baltic Sea is a comparatively well-monitored region, current data and knowledge is insufficient to provide a sound quantification of legacy nutrient loads and much less their abatement costs. A first rough estimation of agricultural legacy nutrient loads yields an accumulation of 0.5–4.0 Mt N and 0.3–1.2 Mt P in the Baltic Sea and 0.4–0.5 Mt P in agricultural soils within the catchment. The costs for removing or immobilising this amount of nutrients via deep water oxygenation, mussel farming and soil gypsum amendment are in the range of few tens to over 100 billion €. These preliminary results are meant as a basis for future studies and show that while requiring serious commitment to funding and implementation, remediating agricultural legacy loads is not infeasible and may even provide economic benefits to local communities in the long run.

scholarly journals Deficiency syndromes in top predators associated with large-scale changes in the Baltic Sea ecosystem

PLoS ONE ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. e0227714 ◽  
Author(s):  
Sanna Majaneva ◽  
Emil Fridolfsson ◽  
Michele Casini ◽  
Catherine Legrand ◽  
Elin Lindehoff ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Large Scale ◽  
The Baltic Sea ◽  
Top Predators ◽  
The Baltic

scholarly journals Effect of ocean acidification and elevated <i>f</i>CO<sub>2</sub> on trace gas production by a Baltic Sea summer phytoplankton community

2016 ◽  
Vol 13 (15) ◽  
pp. 4595-4613 ◽  
Author(s):  
Alison L. Webb ◽  
Emma Leedham-Elvidge ◽  
Claire Hughes ◽  
Frances E. Hopkins ◽  
Gill Malin ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Large Scale ◽  
Gas Production ◽  
Trace Gas ◽  
Research Station ◽  
The Baltic Sea ◽  
Chl A ◽  
The Baltic ◽  
Upwelling Event ◽  
Ambient Co2

Abstract. The Baltic Sea is a unique environment as the largest body of brackish water in the world. Acidification of the surface oceans due to absorption of anthropogenic CO2 emissions is an additional stressor facing the pelagic community of the already challenging Baltic Sea. To investigate its impact on trace gas biogeochemistry, a large-scale mesocosm experiment was performed off Tvärminne Research Station, Finland, in summer 2012. During the second half of the experiment, dimethylsulfide (DMS) concentrations in the highest-fCO2 mesocosms (1075–1333 µatm) were 34 % lower than at ambient CO2 (350 µatm). However, the net production (as measured by concentration change) of seven halocarbons analysed was not significantly affected by even the highest CO2 levels after 5 weeks' exposure. Methyl iodide (CH3I) and diiodomethane (CH2I2) showed 15 and 57 % increases in mean mesocosm concentration (3.8 ± 0.6 increasing to 4.3 ± 0.4 pmol L−1 and 87.4 ± 14.9 increasing to 134.4 ± 24.1 pmol L−1 respectively) during Phase II of the experiment, which were unrelated to CO2 and corresponded to 30 % lower Chl a concentrations compared to Phase I. No other iodocarbons increased or showed a peak, with mean chloroiodomethane (CH2ClI) concentrations measured at 5.3 (±0.9) pmol L−1 and iodoethane (C2H5I) at 0.5 (±0.1) pmol L−1. Of the concentrations of bromoform (CHBr3; mean 88.1 ± 13.2 pmol L−1), dibromomethane (CH2Br2; mean 5.3 ± 0.8 pmol L−1), and dibromochloromethane (CHBr2Cl, mean 3.0 ± 0.5 pmol L−1), only CH2Br2 showed a decrease of 17 % between Phases I and II, with CHBr3 and CHBr2Cl showing similar mean concentrations in both phases. Outside the mesocosms, an upwelling event was responsible for bringing colder, high-CO2, low-pH water to the surface starting on day t16 of the experiment; this variable CO2 system with frequent upwelling events implies that the community of the Baltic Sea is acclimated to regular significant declines in pH caused by up to 800 µatm fCO2. After this upwelling, DMS concentrations declined, but halocarbon concentrations remained similar or increased compared to measurements prior to the change in conditions. Based on our findings, with future acidification of Baltic Sea waters, biogenic halocarbon emissions are likely to remain at similar values to today; however, emissions of biogenic sulfur could significantly decrease in this region.

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