21st century nutrient and oxygen dynamics in the Gulf of Bothnia

2021 ◽  
Author(s):  
Itzel Ruvalcaba Baroni ◽  
Jenny Hieronymus ◽  
Sam Fredriksson ◽  
Lars Arneborg
Keyword(s):  
21St Century ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
Future Projections ◽  
Gulf Of Bothnia ◽  
Bottom Waters ◽  
Baltic Proper ◽  
The Baltic ◽  
Business As Usual ◽  
Historical Scenario

<p>The Gulf of Bothnia is the only sub-basin of the Baltic Sea with no serious eutrophication. However, long-term observations have shown degradation of the water quality over the past years, indicating warning signals for the future. Here, we use a high resolution ocean circulation model including biogeochemistry to study 21st century nutrient and oxygen changes in the Gulf of Bothnia. We analyze ensembles for 5 different scenarios; a historical (1975-2005) and 4 future projections (2006-2100). For the projections, two atmospheric <em>p</em>CO<sub>2 </sub>trajectories are used, RCP4.5 and RCP8.5, and two settings for nutrient loads are applied to each RCP scenario: one following the Baltic Sea Action Plan (BSAP) and the other assuming business as usual. We also test a historical scenario but with no local nutrient loads to better understand the biogeochemical influence of the lateral open boundary. The comparison of observations with the historical scenario shows that oxygen trends are well captured by the model despite a small bias in nutrient concentrations. Our results suggest that the Bothnian Bay is more sensitive to river loads than the Bothnian Sea, which is primarily affected by the inflows from the Baltic proper. All future projections show a decrease in phosphate concentrations and an increase in nitrate concentrations due to lower/higher input of phosphate/nitrate from the Baltic proper. Oxygen concentrations in bottom waters of the Gulf of Bothnia are not susceptible to become hypoxic in the future. However, when business as usual is applied for nutrient loads, oxygen concentrations decrease significantly over the entire future period and short episodes of low oxygen conditions in bottom waters (with less than 5 ml O<sub>2</sub>/l) become more frequent and more pronounced in the Bothnian Sea, especially towards the end of the century.</p><p> </p>

Projected Oceanographical Changes in the Baltic Sea until 2100

2020 ◽  
Author(s):  
H.E. Markus Meier ◽  
Sofia Saraiva
Keyword(s):  
Baltic Sea ◽  
21St Century ◽  
Greenhouse Gas Emission ◽  
Regional Climate ◽  
Future Climate ◽  
Nutrient Load ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
Early 21St Century ◽  
The Baltic

In this article, the concepts and background of regional climate modeling of the future Baltic Sea are summarized and state-of-the-art projections, climate change impact studies, and challenges are discussed. The focus is on projected oceanographic changes in future climate. However, as these changes may have a significant impact on biogeochemical cycling, nutrient load scenario simulations in future climates are briefly discussed as well. The Baltic Sea is special compared to other coastal seas as it is a tideless, semi-enclosed sea with large freshwater and nutrient supply from a partly heavily populated catchment area and a long response time of about 30 years, and as it is, in the early 21st century, warming faster than any other coastal sea in the world. Hence, policymakers request the development of nutrient load abatement strategies in future climate. For this purpose, large ensembles of coupled climate–environmental scenario simulations based upon high-resolution circulation models were developed to estimate changes in water temperature, salinity, sea-ice cover, sea level, oxygen, nutrient, and phytoplankton concentrations, and water transparency, together with uncertainty ranges. Uncertainties in scenario simulations of the Baltic Sea are considerable. Sources of uncertainties are global and regional climate model biases, natural variability, and unknown greenhouse gas emission and nutrient load scenarios. Unknown early 21st-century and future bioavailable nutrient loads from land and atmosphere and the experimental setup of the dynamical downscaling technique are perhaps the largest sources of uncertainties for marine biogeochemistry projections. The high uncertainties might potentially be reducible through investments in new multi-model ensemble simulations that are built on better experimental setups, improved models, and more plausible nutrient loads. The development of community models for the Baltic Sea region with improved performance and common coordinated experiments of scenario simulations is recommended.

scholarly journals Baltic Sea sediments record anthropogenic loads of Cd, Pb, and Zn

2020 ◽  
Author(s):  
Sina Shahabi-Ghahfarokhi ◽  
Sarah Josefsson ◽  
Anna Apler ◽  
Karsten Kalbitz ◽  
Mats Åström ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Environmental Governance ◽  
Heavy Metal Contamination ◽  
The Baltic Sea ◽  
The West ◽  
Large Spatial Scale ◽  
Bottom Waters ◽  
Baltic Proper ◽  
The Baltic ◽  
Bothnian Bay

Abstract The unsustainable settlement and high industrialization around the catchment of the Baltic Sea has left records of anthropogenic heavy metal contamination in Baltic Sea sediments. Here, we show that sediments record post-industrial and anthropogenic loads of Cd, Zn, and Pb over a large spatial scale in the Baltic Sea. We also demonstrate that there is a control on the accumulation of these metals in relation to oxic/anoxic conditions of bottom waters. The total concentrations of Cd, Zn, and Pb were obtained with the near-total digestion method in thirteen cores collected from the Bothnian Bay, the Bothnian Sea, and the west and central Baltic Proper. The lowest average concentrations of Cd, Zn, and Pb were observed in Bothnian Bay (0.4, 125, 40.2 mg kg−1 DW, respectively). In contrast, the highest concentrations were observed in the west Baltic Proper (5.5, 435, and 56.6 mg kg−1 DW, respectively). The results indicate an increasing trend for Cd, Zn, and Pb from the early nineteenth century until the 1970s, followed by a decrease until 2000–2008. However, surface sediments still have concentrations above the pre-industrial values suggested by the Swedish EPA (Cd is 0.2, Zn is 85, and Pb is 31 mg kg−1 DW). The results also show that the pre-industrial Cd, Zn, and Pb concentrations obtained from 3 cores with ages < 1500 B.C. were 1.8, 1.7, and 1.2 times higher, respectively, than the pre-industrial values suggested by the Swedish EPA. To conclude, accumulations of metals in the Baltic Sea are governed by anthropogenic load and the redox conditions of the environment. The significance of correct environmental governance (measures) can be illustrated with the reduction in the pollution of Pb, Zn, and Cd within the Baltic Sea since the 1980s.

scholarly journals Fucus vesiculosus adapted to a life in the Baltic Sea: impacts on recruitment, growth, re-establishment and restoration

2019 ◽  
Vol 62 (1) ◽  
pp. 17-30
Author(s):  
Lena Kautsky ◽  
Susanne Qvarfordt ◽  
Ellen Schagerström
Keyword(s):  
Baltic Sea ◽  
Fucus Vesiculosus ◽  
Reproductive Age ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
Nutrient Runoff ◽  
Low Salinity ◽  
The North ◽  
Baltic Proper ◽  
The Baltic

Abstract Fucus vesiculosus is common both on the tidal coasts of the North Atlantic and in the Baltic Sea, where it has adapted to low salinity and nontidal conditions over the last 7000 years. During the late 1970s and early 1980s, extensive declines of F. vesiculosus populations were reported in the Baltic Proper, mainly attributed to high nutrient loads. During the past 30–40 years, considerable efforts have been made to reduce nutrient runoff to coastal areas but few successful initiatives to restore F. vesiculosus populations have been performed. In this paper, we present how substratum manipulation, i.e. clean rocky surfaces, brushing rocks, Hildenbrandia rubra cover and different filamentous algae, as well as different algal exudates, affect the recruitment and survival of juvenile F. vesiculosus. Further, we show through a 5-year field experiment that it will take at least 4–5 years to reach reproductive age for F. vesiculosus in the Baltic Sea. We also present transplantation studies from two different areas, showing that epiphytic load, light, grazing and type of substratum are some of the factors that need to be taken into consideration in order to achieve successful restoration of F. vesiculosus.

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.

The integrative potential of science and research cooperation for suturing the Baltic Sea region in the 21st century

2021 ◽  
Vol 19 (3) ◽  
pp. 9-32
Author(s):  
Kazimierz Musiał
Keyword(s):  
Baltic Sea ◽  
Case Studies ◽  
21St Century ◽  
Theoretical Framework ◽  
Baltic Region ◽  
The Baltic Sea ◽  
Research Cooperation ◽  
Baltic Sea Region ◽  
The Baltic ◽  
Science And Research

The aim of the article is to demonstrate how science and researchcooperation may help to reintegrate the Baltic region in the 21st century withthe participation of Russia. This is done through the analysis of documentsand strategies of Baltic Sea regionalism in the context of the regional knowledgeregime. Attention is paid to different positionalities of the regional actorsand their narratives. The theoretical framework is secured by an analysis ofcritical junctures drawing on case studies from the years 1989-91 and 2014 andthe subsequent reconfiguration of the power / knowledge nexus. The analysisshows that this reconfiguration actively contributes to creating and changingthe content and context of the Baltic Sea regionalism as based on new symbolic,economic, and political capitals. The conclusion points to the potentialof Russia’s involvement in the co-creation of the regional knowledge regimeand defines the conditions and methods of possible cooperation.

scholarly journals An integrated simulation model to evaluate national measures for the abatement of agricultural nutrients in the Baltic Sea

2009 ◽  
Vol 18 (3-4) ◽  
pp. 440-459 ◽  
Author(s):  
K. HYYTIÄINEN ◽  
H. AHTIAINEN ◽  
J. HEIKKILÄ
Keyword(s):  
Water Quality ◽  
Simulation Model ◽  
Baltic Sea ◽  
Arable Land ◽  
Gulf Of Finland ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
The Baltic ◽  
Bothnian Bay ◽  
The Gulf Of Finland

This study introduces a prototype model for evaluating measures to abate agricultural nutrients in the Baltic Sea from a Finnish national perspective. The stochastic simulation model integrates nutrient dynamics of nitrogen and phosphorus in the sea basins adjoining the Finnish coast, nutrient loads from land and other sources, benefits from nutrient abatement (in the form of recreation and other ecosystem services) and the costs of agricultural abatement activities. The aim of the study is to present the overall structure of the model and to demonstrate its potential using preliminary parameters. The model is made flexible for further improvements in all of its ecological and economic components. The results of a sensitivity analysis suggest that investments in reducing the nutrient load from arable land in Finland would become profitable only if the neighboring countries in the northern Baltic committed themselves to similar reductions. Environmental investments for improving water quality yield the highest returns for the Bothnian Bay and the Gulf of Finland, with smaller returns for the Bothnian Sea. Somewhat surprisingly, in the Bothnian Bay the abatement activities become profitable from the national viewpoint, because the riverine loads from Finland represent a high proportion of the total nutrient loads. In the Gulf of Finland, this proportion is low, but the size of the coastal population benefiting from improved water quality is high.;

Projected Changes in Wave Conditions in the Baltic Sea by the end of 21st Century and the Corresponding Shoreline Changes

2016 ◽  
Vol 75 (sp1) ◽  
pp. 1012-1016 ◽  
Author(s):  
Ülo Suursaar ◽  
Hannes Tõnisson ◽  
Victor Alari ◽  
Urmas Raudsepp ◽  
Henri Rästas ◽  
...  
Keyword(s):  
Baltic Sea ◽  
21St Century ◽  
The Baltic Sea ◽  
Shoreline Changes ◽  
Wave Conditions ◽  
The Baltic ◽  
Projected Changes

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.

scholarly journals Nutrient transports in the Baltic Sea – results from a 30-year physical–biogeochemical reanalysis

2017 ◽  
Vol 14 (8) ◽  
pp. 2113-2131 ◽  
Author(s):  
Ye Liu ◽  
H. E. Markus Meier ◽  
Kari Eilola
Keyword(s):  
Baltic Sea ◽  
Cross Sections ◽  
Ocean Model ◽  
Optimal Interpolation ◽  
Nutrient Concentrations ◽  
Biogeochemical Model ◽  
The Baltic Sea ◽  
Gulf Of Riga ◽  
Baltic Proper ◽  
The Baltic

Abstract. Long-term oxygen and nutrient transports in the Baltic Sea are reconstructed using the Swedish Coastal and Ocean Biogeochemical model (SCOBI) coupled to the Rossby Centre Ocean model (RCO). Two simulations with and without data assimilation covering the period 1970–1999 are carried out. Here, the weakly coupled scheme with the Ensemble Optimal Interpolation (EnOI) method is adopted to assimilate observed profiles in the reanalysis system. The reanalysis shows considerable improvement in the simulation of both oxygen and nutrient concentrations relative to the free run. Further, the results suggest that the assimilation of biogeochemical observations has a significant effect on the simulation of the oxygen-dependent dynamics of biogeochemical cycles. From the reanalysis, nutrient transports between sub-basins, between the coastal zone and the open sea, and across latitudinal and longitudinal cross sections are calculated. Further, the spatial distributions of regions with nutrient import or export are examined. Our results emphasize the important role of the Baltic proper for the entire Baltic Sea, with large net transport (export minus import) of nutrients from the Baltic proper into the surrounding sub-basins (except the net phosphorus import from the Gulf of Riga and the net nitrogen import from the Gulf of Riga and Danish Straits). In agreement with previous studies, we found that the Bothnian Sea imports large amounts of phosphorus from the Baltic proper that are retained in this sub-basin. For the calculation of sub-basin budgets, the location of the lateral borders of the sub-basins is crucial, because net transports may change sign with the location of the border. Although the overall transport patterns resemble the results of previous studies, our calculated estimates differ in detail considerably.

scholarly journals How effective are River Basin Management Plans in reaching the nutrient load reduction targets?

AMBIO ◽  
2020 ◽  
Author(s):  
Mikołaj Piniewski ◽  
Sirkka Tattari ◽  
Jari Koskiaho ◽  
Olle Olsson ◽  
Faruk Djodjic ◽  
...  
Keyword(s):  
Baltic Sea ◽  
River Basin ◽  
River Basin Management ◽  
Load Reduction ◽  
Nutrient Loads ◽  
Basin Management ◽  
The Baltic Sea ◽  
River Basin Management Plans ◽  
Management Plans ◽  
The Baltic

Abstract Riverine nutrient loads are among the major causes of eutrophication of the Baltic Sea. This study applied the Soil & Water Assessment Tool (SWAT) in three catchments flowing to the Baltic Sea, namely Vantaanjoki (Finland), Fyrisån (Sweden), and Słupia (Poland), to simulate the effectiveness of nutrient control measures included in the EU’s Water Framework Directive River Basin Management Plans (RBMPs). Moreover, we identified similar, coastal, middle-sized catchments to which conclusions from this study could be applicable. The first modelling scenario based on extrapolation of the existing trends affected the modelled nutrient loads by less than 5%. In the second scenario, measures included in RBMPs showed variable effectiveness, ranging from negligible for Słupia to 28% total P load reduction in Vantaanjoki. Adding spatially targeted measures to RBMPs (third scenario) would considerably improve their effectiveness in all three catchments for both total N and P, suggesting a need to adopt targeting more widely in the Baltic Sea countries.

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