scholarly journals Climate dependent diatom production is preserved in biogenic Si isotope signatures

2011 ◽  
Vol 8 (11) ◽  
pp. 3491-3499 ◽  
Author(s):  
X. Sun ◽  
P. Andersson ◽  
C. Humborg ◽  
B. Gustafsson ◽  
D. J. Conley ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Sediment Core ◽  
Large Scale ◽  
Isotope Composition ◽  
The Baltic Sea ◽  
Si Isotopes ◽  
The Baltic ◽  
Si Isotope ◽  
Bothnian Bay ◽  
Second Period

Abstract. The aim of this study was to reconstruct diatom production in the subarctic northern tip of the Baltic Sea, Bothnian Bay, based on down-core analysis of Si isotopes in biogenic silica (BSi). Dating of the sediment showed that the samples covered the period 1820 to 2000. The sediment core record can be divided into two periods, an unperturbed period from 1820 to 1950 and a second period affected by human activities (from 1950 to 2000). This has been observed elsewhere in the Baltic Sea. The shift in the sediment core record after 1950 is likely caused by large scale damming of rivers. Diatom production was inferred from the Si isotope composition which ranged between δ30Si −0.18‰ and +0.58‰ in BSi, and assuming fractionation patterns due to the Raleigh distillation, the production was shown to be correlated with air and water temperature, which in turn were correlated with the mixed layer (ML) depth. The sedimentary record showed that the deeper ML depth observed in colder years resulted in less production of diatoms. Pelagic investigations in the 1990's have clearly shown that diatom production in the Baltic Sea is controlled by the ML depth. Especially after cold winters and deep water mixing, diatom production was limited and dissolved silicate (DSi) concentrations were not depleted in the water column after the spring bloom. Our method corroborates these findings and offers a new method to estimate diatom production over much longer periods of time in diatom dominated aquatic systems, i.e. a large part of the world's ocean and coastal seas.

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

The stable tungsten isotope composition of sapropels and manganese-rich sediments from the Baltic Sea

2022 ◽  
Vol 578 ◽  
pp. 117303
Author(s):  
Florian Kurzweil ◽  
Olaf Dellwig ◽  
Martin Wille ◽  
Ronny Schoenberg ◽  
Helge W. Arz ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Isotope Composition ◽  
The Baltic Sea ◽  
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.

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.;

scholarly journals Development of marine landscape maps for the Baltic Sea and the Kattegat using geophysical and hydrographical parameters

2007 ◽  
Vol 13 ◽  
pp. 61-64 ◽  
Author(s):  
Zyad K. Al-Hamdani ◽  
Johnny Reker ◽  
Jørgen O. Leth ◽  
Anu Reijonen ◽  
Aarno T. Kotilainen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Marine Environment ◽  
Leisure Activities ◽  
Biological Information ◽  
Marine Biodiversity ◽  
The European Union ◽  
The Baltic Sea ◽  
Marine Habitats ◽  
The Baltic ◽  
Bothnian Bay

The Baltic Sea is one of the largest brackish water bodies in the world (Segerstråle 1957) with a number of basins varying from almost fresh water in the northern part of the Bothnian Bay via the more brackish conditions in the southern part to the saline waters of the Kattegat. The Baltic Sea is subject to severe environmental degradation caused by commercial and leisure activities, including fisheries, dredging, tourism, coas t a l development and land-based pollution sources. This causes severe pressures on vulnerable marine habitats and natural re- sources, and a tool for aiding marine management is therefore strongly needed. The marine landscape concept presented by Roff &Taylor (2000) is based on the use of available broad-scale geological, physical and hydrographical data to prepare ecologically meaningful maps for areas with little or no biological information. The concept, which was elaborated by Day & Roff (2000) was applied in UK waters (Connor et al. 2006) before it was adopted by the BALANCE project described here. The aim of developing marine landscape maps is to characterise the marine environment of the Baltic Sea region (the Baltic Sea together with the Kattegat) using geophysical and hydrographical parameters. Such maps can be applied, for example, to an assessment of the Baltic-wide network of marine protected areas, and thus provide a sustainable ecosystem-based approach to the protection of the marine environment from human activities, and contribute to the conservation of marine biodiversity. The BALANCE project is based on transnational and cross-sectoral co-operation with participants from nine countries surrounding the Baltic Sea as well as Norway (Fig. 1), and is partially financed by the European Union through the BSR INTERREG IIIB programme.

scholarly journals A century of genetic homogenization in Baltic salmon—evidence from archival DNA

2021 ◽  
Vol 288 (1949) ◽  
Author(s):  
Johan Östergren ◽  
Stefan Palm ◽  
John Gilbey ◽  
Göran Spong ◽  
Johan Dannewitz ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Large Scale ◽  
Isolation By Distance ◽  
Anthropogenic Impacts ◽  
Genetic Change ◽  
Past Century ◽  
The Baltic Sea ◽  
The Baltic ◽  
Archival Dna

Intra-species genetic homogenization arising from anthropogenic impacts is a major threat to biodiversity. However, few taxa have sufficient historical material to systematically quantify long-term genetic changes. Using archival DNA collected over approximately 100 years, we assessed spatio-temporal genetic change in Atlantic salmon populations across the Baltic Sea, an area heavily impacted by hydropower exploitation and associated with large-scale mitigation stocking. Analysis was carried out by screening 82 SNPs in 1680 individuals from 13 Swedish rivers. We found an overall decrease in genetic divergence and diminished isolation by distance among populations, strongly indicating genetic homogenization over the past century. We further observed an increase in genetic diversity within populations consistent with increased gene flow. The temporal genetic change was lower in larger wild populations than in smaller wild and hatchery-reared ones, indicating that larger populations have been able to support a high number of native spawners in relation to immigrants. Our results demonstrate that stocking practices of salmon in the Baltic Sea have led to the homogenization of populations over the last century, potentially compromising their ability to adapt to environmental change. Stocking of reared fish is common worldwide, and our study is a cautionary example of the potentially long-term negative effects of such activities.

Statistical Downscaling of daily extreme Sea Level with Random Forest: Examples from South-East Asia and the Baltic Sea

2020 ◽  
Author(s):  
Svenja Bierstedt ◽  
Eduardo Zorita ◽  
Birgit Hünicke
Keyword(s):  
Random Forest ◽  
Baltic Sea ◽  
East Asia ◽  
Sea Level ◽  
Large Scale ◽  
South East Asia ◽  
The Baltic Sea ◽  
Sea Levels ◽  
Extreme Sea Levels ◽  
The Baltic

&lt;p&gt;The coastlines of the Baltic Sea and Indonesia are both relatively complex, so that the estimation of extreme sea levels caused by the atmospheric forcing becomes complex with conventional methods. Here, we explore whether Machine Learning methods can provide a model surrogate to compute more rapidly daily extremes in sea level from large-scale atmosphere-ocean fields. We investigate the connections between the atmospheric and ocean drivers of local extreme sea level in South East Asia and along the Baltic Sea based on statistical analysis by Random Forest Models, driven by large-scale meteorological predictors and daily extreme sea level measured by tide-gauge records over the last few decades.&lt;/p&gt;&lt;p&gt;First results show that in some Indonesian areas extremes are driven by large-scale climate fields; in other areas they are incoherently driven by local processes. An area where random forest predicted extremes show good correspondence to observed extremes is found to be the Malaysian coastline. For the Indonesian coasts, the Random Forest Algorithm was unable to predict extreme sea levels in line with observations. Along the Baltic Sea, in contrast, the Random Forest model is able to produce reasonable estimations of extreme sea levels based on the large-scale atmospheric fields. An analysis of the interrelations of extreme sea levels in the South Asia regions suggests that either the data quality may be compromised in some regions or that other forcing factors, distinct from the large-scale atmospheric fields, may also be involved.&lt;/p&gt;

scholarly journals The role of climate and fisheries on the temporal changes in the Bothnian Bay foodweb

2016 ◽  
Vol 73 (7) ◽  
pp. 1739-1749 ◽  
Author(s):  
Zeynep Pekcan-Hekim ◽  
Anna Gårdmark ◽  
Agnes M. L. Karlson ◽  
Pirkko Kauppila ◽  
Mikaela Bergenius ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Trophic Levels ◽  
Strong Increase ◽  
The Baltic Sea ◽  
Key Species ◽  
Long Term Changes ◽  
Spawning Stock ◽  
The Baltic ◽  
Bothnian Bay

Abstract Climate change, eutrophication, and fishing are main pressures associated with changes in the abiotic and biotic environment in several sub-basins of the Baltic Sea. Identifying the nature of such changes is of relative importance for fisheries and environmental management. The Bothnian Bay is the northernmost sub-basin in the Baltic Sea and the responses of the foodweb to long-term changes in combined pressures have not been investigated. In this study, we explore long-term changes in the Bothnian Bay foodweb, represented by key species across all trophic levels over the past 34 years, and identify potential environmental and anthropogenic drivers. The results indicate that salinity is the most important driver to explain changes in the composition of the offshore biota in the Bothnian Bay. These changes are probably driven by indirect effects of salinity rather than bottom-up effects. A decline in the herring spawning-stock biomass was most plausibly attributed to an increased competition for food due to a parallel increase in vendace, which uses the same food resources (zooplankton and zoobenthos) and may benefit from declining salinity due to its limnic origin. A strong increase in the abundance of grey seal and ringed seal populations was seen in the late 2000s but was not related to any of the pressure variables analysed. Temperature and nutrients were not identified as important drivers of changes in the overall biota. Our study explores correlative relationships between variables and identifies potential interactions in the foodweb to generate hypotheses for further studies.

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