scholarly journals Recent benthic foraminifera in the Flensburg Fjord (Western Baltic Sea)

2009 ◽  
Vol 28 (2) ◽  
pp. 131-142 ◽  
Author(s):  
Irina Polovodova ◽  
Anna Nikulina ◽  
Joachim Schönfeld ◽  
Wolf-Christian Dullo
Keyword(s):  
Baltic Sea ◽  
Benthic Foraminifera ◽  
Salt Water ◽  
Outer Part ◽  
The Baltic Sea ◽  
Fine Grained ◽  
Kiel Bight ◽  
Sandy Habitat ◽  
The 1960S ◽  
The Baltic

Abstract. Living benthic foraminifera of Flensburg Fjord were surveyed in June 2006. The muddy and organic-rich sediments of the inner fjord were dominated by Elphidium incertum. E. incertum and E. excavatum were frequent in muds and sandy muds of the fjord loop around Holnis Peninsula and in the outer part. Gelting Bay yielded a different biofacies, indicating a brackish and sandy habitat, poor in food supply and with microfauna dominated by Ammonia beccarii and E. albiumbilicatum. The central fjord and nearshore zones of the loop were characterized by sandy muds, relatively poor in food and occupied by A. beccarii, E. incertum and E. excavatum subspecies. High abundances of E. excavatum were encountered in the innermost fjord, with fine-grained and organic-rich muddy sediments.A comparison with previous studies revealed the profound changes in species composition in the outer Flensburg Fjord since the 1970s. A decline in numbers of Ammotium cassis and flourishing of Ammonia beccarii in Gelting Bay were recognized. These changes are most likely associated with decreased intensity and frequency of salt-water inflows into the Baltic Sea since the 1960s. It is inferred that the decline of A. cassis is similar to that of Eggerelloides scaber, which currently is found only in depressions of Kiel Bight with higher salinity.

scholarly journals GIS analysis of effects of future Baltic Sea level rise on the island of Gotland, Sweden

2016 ◽  
Author(s):  
Karin Ebert ◽  
Karin Ekstedt ◽  
Jerker Jarsjö
Keyword(s):  
Baltic Sea ◽  
Sea Level Rise ◽  
Sea Level ◽  
Coastal Aquifers ◽  
Salt Water ◽  
Global Perspective ◽  
Salt Water Intrusion ◽  
The Baltic Sea ◽  
Water Intrusion ◽  
The Baltic

Abstract. Future sea level rise as a consequence of global warming will affect the world's coastal regions. Even though the pace of sea level rise is not clear, the consequences will be severe and global. Commonly the effects of future sea level rise are investigated for relatively vulnerable development countries; however, a whole range of varying regions need to be considered in order to improve the understanding of global consequences. In this paper we investigate consequences of future sea level rise along the coast of the Baltic Sea island of Gotland, Sweden, with the aim to fill knowledge gaps regarding comparatively well-suited areas in non-development countries. We study both the quantity of loss of infrastructure, cultural and natural values for the case of a two metre sea level rise of the Baltic Sea, and the effects of climate change on seawater intrusion in coastal aquifers, causing the indirect effect of salt water intrusion in wells. We conduct a multi-criteria risk analysis by using Lidar data on land elevation and GIS-vulnerability mapping, which gives formerly unimaginable precision in the application of distance and elevation parameters. We find that in case of a 2 m sea level rise, 3 % of the land area of Gotland, corresponding to 99 km2, will be inundated. The features most strongly affected are items of touristic or nature values, including camping places, shore meadows, sea stack areas, and endangered plants and species habitats. In total, 231 out of 7354 wells will be directly inundated, and the number of wells in the high-risk zone for saltwater intrusion in wells will increase considerably. Some values will be irreversibly lost due to e.g. inundation of sea stacks and the passing of tipping points for sea water intrusion into coastal aquifers; others might simply be moved further inland, but this requires considerable economic means and prioritization. With nature tourism being one of the main income sources of Gotland, monitoring and planning is required to meet the changes. Seeing Gotland in a global perspective, this island shows that holistic multi-feature studies of future consequences of sea level rise are required, to identify overall consequences for individual regions.

Environmental factors affecting recent benthic foraminiferal distribution in the south-eastern Baltic Sea

Baltica ◽  
2020 ◽  
Vol 33 (1) ◽  
pp. 58-70
Author(s):  
Ekaterina Ponomarenko ◽  
Viktor Krechik ◽  
Evgenia Dorokhova
Keyword(s):  
Organic Carbon ◽  
Baltic Sea ◽  
Benthic Foraminifera ◽  
Bottom Water ◽  
Environmental Parameters ◽  
Organic Carbon Content ◽  
The South ◽  
The Baltic Sea ◽  
South Eastern ◽  
The Baltic

The Baltic Sea is characterized by a restricted exchange of deep waters due to permanent stratification of the water column. The aim of the present study is to investigate the distribution of benthic foraminifera in the south-eastern part of the Baltic Sea in relation to environmental parameters. The distribution of benthic foraminifera was analyzed in 26 surface sediment samples collected in the south-eastern part of the Baltic Sea and in the Bornholm Basin during springtime and wintertime 2016. Foraminiferal diversity in the studied region was extremely low. Agglutinated specimens dominated the assemblages and were represented by small-sized individuals which belong to Psammosphaera, Pseudothurammina, Saccammina, and Reophax genera. Calcareous foraminifera were dominated by Cribroelphidium genus. Micropaleontological data were compared to the environmental parameters characterizing bottom water (temperature, salinity, and dissolved oxygen content) and substrate conditions (grain size composition and total organic carbon content). Higher foraminiferal concentrations and diversity were found in deeper parts of the study region where fine-grained sediments with a higher total organic carbon content were accumulated under stable hydrographical conditions. Calcareous tests were found only at the stations with elevated salinity, indicating that bottom water salinity is the main factor limiting the distribution of calcareous foraminifera. On the other hand, substrate parameters and hydrodynamic conditions appear to play a major role in the distribution of agglutinated foraminifera.

scholarly journals Investigating interdecadal salinity changes in the Baltic Sea in a 1850–2008 hindcast simulation

2020 ◽  
Vol 16 (4) ◽  
pp. 1617-1642 ◽  
Author(s):  
Hagen Radtke ◽  
Sandra-Esther Brunnabend ◽  
Ulf Gräwe ◽  
H. E. Markus Meier
Keyword(s):  
Baltic Sea ◽  
River Runoff ◽  
Sea Water ◽  
Salt Water ◽  
Salinity Range ◽  
Historical Period ◽  
The Baltic Sea ◽  
High Salinity Water ◽  
Salinity Changes ◽  
The Baltic

Abstract. Interdecadal variability in the salinity of the Baltic Sea is dominated by a 30-year cycle with a peak-to-peak amplitude of around 0.4 g kg−1 at the surface. Such changes may have substantial consequences for the ecosystem, since species are adapted to a suitable salinity range and may experience habitat shifts. It is therefore important to understand the drivers of such changes. We use both analysis of empirical data and a numerical model reconstruction for the period of 1850–2008 to explain these interdecadal changes. The model explains 93 % and 52 % of the variance in the observed interdecadal salinity changes at the surface and the bottom, respectively, at an oceanographic station at Gotland Deep. It is known that the 30-year periodicity coincides with a variability in river runoff. Periods of enhanced runoff are followed by lower salinities. We demonstrate, however, that the drop in mean salinity cannot be understood as a simple dilution of the Baltic Sea water by freshwater. Rather, the 30-year periodicity in river runoff occurs synchronously with a substantial variation in salt water import across Darss Sill. Fewer strong inflow events occur in periods of enhanced river runoff. This reduction in the import of high-salinity water is the main reason for the freshening of the water below the permanent halocline. In the bottom waters, the variation in salinity is larger than at the surface. As a consequence, the surface layer salinity variation is caused by a combination of both effects: a direct dilution by river water and a reduced upward diffusion of salt as a consequence of reduced inflow activity. Our findings suggest that the direct dilution effect is responsible for 27 % of the salinity variations only. It remains unclear whether the covariation in river runoff and inflow activity are only a coincidental correlation during the historical period or whether a mechanistic link exists between the two quantities, e.g. whether both are caused by the same atmospheric patterns.

scholarly journals Hypoxia and cyanobacteria blooms - are they really natural features of the late Holocene history of the Baltic Sea?

2010 ◽  
Vol 7 (8) ◽  
pp. 2567-2580 ◽  
Author(s):  
L. Zillén ◽  
D. J. Conley
Keyword(s):  
Baltic Sea ◽  
Large Scale ◽  
Environmental Changes ◽  
Salt Water ◽  
Climate Forcing ◽  
Medieval Period ◽  
The Baltic Sea ◽  
Baltic Basin ◽  
Cyanobacteria Blooms ◽  
The Baltic

Abstract. During the last century (1900s) industrialized forms of agriculture and human activities have caused eutrophication of Baltic Sea waters. As a consequence, the hypoxic zone in the Baltic Sea has increased, especially during the last 50 years, and has caused severe ecosystem disturbance. Climate forcing has been proposed to be responsible for the reported trends in hypoxia (< 2 mg/l O2) both during the last c. 100 years (since c. 1900 AD) and the Medieval Period. By contrast, investigations of the degree of anthropogenic forcing on the ecosystem on long time-scales (millennial and greater) have not been thoroughly addressed. This paper examines evidence for anthropogenic disturbance of the marine environment beyond the last century through the analysis of the human population growth, technological development and land-use changes in the drainage area. Natural environmental changes, i.e. changes in the morphology and depths of the Baltic basin and the sills, were probably the main driver for large-scale hypoxia during the early Holocene (8000–4000 cal yr BP). We show that hypoxia during the last two millennia has followed the general expansion and contraction trends in Europe and that human perturbation has been an important driver for hypoxia during that time. Hypoxia occurring during the Medieval Period coincides with a doubling of the population (from c. 4.6 to 9.5 million) in the Baltic Sea watershed, a massive reclamation of land in both established and marginal cultivated areas and significant increases in soil nutrient release. The role of climate forcing on hypoxia in the Baltic Sea has yet to be demonstrated convincingly, although it could have helped to sustain hypoxia through enhanced salt water inflows or through changes in hydrological inputs. In addition, cyanobacteria blooms are not natural features of the Baltic Sea as previously deduced, but are a consequence of enhanced phosphorus release from the seabed that occurs during hypoxia.

Seasonal variability of phytoplankton in the shallow waters of the southern Baltic Sea

2017 ◽  
Vol 32 (1) ◽  
pp. 0-0
Author(s):  
Iwona Zaboroś
Keyword(s):  
Baltic Sea ◽  
Coastal Areas ◽  
Shallow Waters ◽  
Spatial And Temporal Variability ◽  
The Baltic Sea ◽  
River Waters ◽  
Phytoplankton Structure ◽  
Sandy Habitat ◽  
Temporal And Spatial ◽  
The Baltic

The Baltic Sea is characterized by seasonal variation of phytoplankton structure. These organisms are particularly sensitive to changes in various environmental factors. Because of annually repeated changes, turnover of species composition, abundance and biomass of phytoplankton is observed. Spatial and temporal variability of individual phytoplankton groups is diversified in a district parts of the Baltic Sea. Therefore, of three different coastal areas were chosen: Ustka – estuary habitat, Poddąbie – sandy habitat and Rowy – rocky bottom habitat. The aim of this paper is to determine temporal and spatial structure of phytoplankton occurrence chosen coastal areas between November 2014 and September 2016. All three studies regions the same dominants, abundance and biomass were observed. Only in Ustka region increase of the diatoms was observed. Which could see the cause of river waters wave. Seasonal phytoplankton studies in three selected habitats revealed, that in those areas that abundance and biomass is similar (75%-80%). Based on this evaluation it is can be stated that conducting phytoplankton more frequently is more important than number of research stations.

scholarly journals Reconstructing the population dynamics of sprat (Sprattus sprattus balticus) in the Baltic Sea in the 20th century

2012 ◽  
Vol 69 (6) ◽  
pp. 1010-1018 ◽  
Author(s):  
Margit Eero
Keyword(s):  
Population Dynamics ◽  
Baltic Sea ◽  
20Th Century ◽  
Human Impacts ◽  
Management Strategies ◽  
The Baltic Sea ◽  
Sprattus Sprattus ◽  
1960S And 1970S ◽  
The 1960S ◽  
The Baltic

Abstract Eero, M. 2012. Reconstructing the population dynamics of sprat (Sprattus sprattus balticus) in the Baltic Sea in the 20th century. – ICES Journal of Marine Science, 69: 1010–1018 . Long time-series of population dynamics are increasingly needed in order to understand human impacts on marine ecosystems and support their sustainable management. In this study, the estimates of sprat (Sprattus sprattus balticus) biomass in the Baltic Sea were extended back from the beginning of ICES stock assessments in 1974 to the early 1900s. The analyses identified peaks in sprat spawner biomass in the beginning of the 1930s, 1960s, and 1970s at ∼900 kt. Only a half of that biomass was estimated for the late 1930s, for the period from the late 1940s to the mid-1950s, and for the mid-1960s. For the 1900s, fisheries landings suggest a relatively high biomass, similar to the early 1930s. The exploitation rate of sprat was low until the development of pelagic fisheries in the 1960s. Spatially resolved analyses from the 1960s onwards demonstrate changes in the distribution of sprat biomass over time. The average body weight of sprat by age in the 1950s to 1970s was higher than at present, but lower than during the 1980s to 1990s. The results of this study facilitate new analyses of the effects of climate, predation, and anthropogenic drivers on sprat, and contribute to setting long-term management strategies for the Baltic Sea.

scholarly journals Explaining interdecadal salinity changes in the Baltic Sea in a 1850–2008 hindcast simulation

2019 ◽  
Author(s):  
Hagen Radtke ◽  
Sandra-Esther Brunnabend ◽  
Ulf Gräwe ◽  
H. E. Markus Meier
Keyword(s):  
Baltic Sea ◽  
River Runoff ◽  
Sea Water ◽  
Salt Water ◽  
Historical Period ◽  
The Baltic Sea ◽  
High Salinity Water ◽  
Bottom Waters ◽  
Long Term Trends ◽  
The Baltic

Abstract. The detection of historical long-term trends is often complicated by interdecadal variability in the time series of interest. A mechanistic understanding of the causes of this variability allows to separate the signals. Salinity of the Baltic Sea contains a dominant 30-year cycle with a peak-to-peak amplitude of around 0.4 g kg−1 at the surface. We use both analysis of empirical data and a numerical model reconstruction for the period of 1850–2008 to explain these changes. It is known that the 30-year periodicity coincides with a variability in river runoff. Periods of enhanced runoff are followed by lower salinities. We demonstrate, however, that the drop in mean salinity cannot be understood as a simple dilution of the Baltic Sea water by freshwater. Rather, the 30-year periodicity in river runoff occurs synchronously with a substantial variation in salt water import across Darss Sill. Fewer strong inflow events occur in periods of enhanced river runoff. This reduction in the import of high-salinity water is the main reason for the freshening of the water below the permanent halocline. In the bottom waters, the variation in salinity is larger than at the surface. As a consequence, the surface layer salinity variation is caused by a combination of both effects, a direct dilution by river water and a reduced upward diffusion of salt as a consequence of reduced inflow activity. It remains unclear whether the covariation in river runoff and inflow activity are only a spurious correlation during the historical period, or a mechanistic link exists between the two quantities, e.g. both are caused by the same atmospheric patterns.

scholarly journals Hypoxia and cyanobacterial blooms are not natural features of the Baltic Sea

2010 ◽  
Vol 7 (2) ◽  
pp. 1783-1812 ◽  
Author(s):  
L. Zillén ◽  
D. J. Conley
Keyword(s):  
Baltic Sea ◽  
Large Scale ◽  
Environmental Changes ◽  
Salt Water ◽  
Cyanobacterial Blooms ◽  
Climate Forcing ◽  
Medieval Period ◽  
The Baltic Sea ◽  
Baltic Basin ◽  
The Baltic

Abstract. During the last century (1900s) industrialized forms of agriculture and human activities have caused extensive eutrophication of Baltic Sea waters. As a consequence, the Baltic Sea developed a hypoxic zone that has caused serve ecosystem disturbance. Climate forcing has also been proposed to be responsible for the reported trends in hypoxia (<2 mg/l O2) both during the last c. 100 years and during the Medieval Period. By contrast, investigations on the degree of anthropogenic forcing on the ecosystem on long time-scales (millennial) have not been thoroughly addressed. This paper critically examines evidence for anthropogenic disturbance of the marine environment beyond the last century through the analysis of the population growth, technological development and land-use changes in the drainage area. Natural environmental changes, i.e. changes in the morphology and depths of the Baltic basin and the sills, were probably the main driver for large-scale hypoxia during the early Holocene (8000–4000 cal. yr BP). We show that hypoxia during the last two millennia has followed the general expansion and contraction trends in Europe and that human perturbations have been an important driver for hypoxia during that time. Hypoxia occurring during the Medieval Period coincides with a doubling of the population (from c. 4.6 to 9.5 million), a massive reclamation of land in both established and marginal cultivated areas and significant increases in soil nutrient release. The role of climate forcing on hypoxia in the Baltic Sea has yet to be convincingly demonstrated, although it could have contributed to sustain hypoxia through enhanced salt water inflows or through changes in hydrological inputs. In addition, cyanobacteria blooms are not natural features of the Baltic Sea as previously hypothesized, but are a consequence of enhanced phosphorus release that occurs together with hypoxia.

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