Occurrence of cyanobacterial blooms in the baltic sea in relation to environmental conditions

1997 ◽  
Vol 82 (2) ◽  
pp. 169-184 ◽  
Author(s):  
Norbert Wasmund
Keyword(s):  
Baltic Sea ◽  
Environmental Conditions ◽  
Cyanobacterial Blooms ◽  
The Baltic Sea ◽  
The Baltic

The History of Cyanobacterial Blooms in the Baltic Sea

AMBIO ◽  
2001 ◽  
Vol 30 (4) ◽  
pp. 172-178 ◽  
Author(s):  
Terttu Finni ◽  
Kaisa Kononen ◽  
Riitta Olsonen ◽  
Kerstin Wallström
Keyword(s):  
Baltic Sea ◽  
Cyanobacterial Blooms ◽  
The Baltic Sea ◽  
History Of ◽  
The Baltic

scholarly journals A three-dimensional view on biodiversity changes: spatial, temporal, and functional perspectives on fish communities in the Baltic Sea

2018 ◽  
Vol 75 (7) ◽  
pp. 2463-2475 ◽  
Author(s):  
Romain Frelat ◽  
Alessandro Orio ◽  
Michele Casini ◽  
Andreas Lehmann ◽  
Bastien Mérigot ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Marine Ecosystem ◽  
Fish Communities ◽  
The Baltic Sea ◽  
Functional Richness ◽  
Holistic Understanding ◽  
The Baltic

Abstract Fisheries and marine ecosystem-based management requires a holistic understanding of the dynamics of fish communities and their responses to changes in environmental conditions. Environmental conditions can simultaneously shape the spatial distribution and the temporal dynamics of a population, which together can trigger changes in the functional structure of communities. Here, we developed a comprehensive framework based on complementary multivariate statistical methodologies to simultaneously investigate the effects of environmental conditions on the spatial, temporal and functional dynamics of species assemblages. The framework is tested using survey data collected during more than 4000 fisheries hauls over the Baltic Sea between 2001 and 2016. The approach revealed the Baltic fish community to be structured into three sub-assemblages along a strong and temporally stable salinity gradient decreasing from West to the East. Additionally, we highlight a mismatch between species and functional richness associated with a lower functional redundancy in the Baltic Proper compared with other sub-areas, suggesting an ecosystem more susceptible to external pressures. Based on a large dataset of community data analysed in an innovative and comprehensive way, we could disentangle the effects of environmental changes on the structure of biotic communities—key information for the management and conservation of ecosystems.

scholarly journals Reconstructing N<sub>2</sub>-fixing cyanobacterial blooms in the Baltic Sea beyond observations using 6- and 7-methylheptadecanes in sediments as specific biomarkers

2019 ◽  
Author(s):  
Jérôme Kaiser ◽  
Norbert Wasmund ◽  
Mati Kahru ◽  
Anna K. Wittenborn ◽  
Regina Hansen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Time History ◽  
Atlantic Multidecadal Oscillation ◽  
Cyanobacterial Blooms ◽  
The Baltic Sea ◽  
Natural Processes ◽  
Baltic Sea Region ◽  
History Of ◽  
Diazotrophic Cyanobacteria ◽  
The Baltic

Abstract. Summer cyanobacterial blooms represent a threat for the Baltic Sea ecosystem, causing deoxygenation of the bottom water and the spread of the so-called dead zones. The time history of the Baltic Sea cyanobacterial blooms is known from in situ and satellite observations since the early 1980s, but still not well understood. By comparing both weekly-resolved trap sediments and a well-dated sediment core from the Eastern Gotland Basin with monitoring and satellite cyanobacterial data of the last ca. 35 years, it is shown here that 6- and 7-methylheptadecane lipids (expressed as 6+7Me-C17:0) are robust semi-quantitative biomarkers for diazotrophic cyanobacteria, and likely mainly for Nodularia spumigena. Using this organic proxy, it was thus possible to reconstruct the history of cyanobacterial blooms beyond the observational period with a resolution of 2–4 years since 1860. Cyanobacteria were constantly present, but in relatively low abundance until 1920, when they started to alternate between periods with high and low abundance. Interestingly, there seems to be no significant increase in cyanobacterial abundance in the 1950s, when eutrophication and deoxygenation of the Baltic Sea increased considerably. Decadal to multi-decadal fluctuations are likely rather related to variability in the Baltic Sea surface temperature and, ultimately, to the Atlantic Multidecadal Oscillation. A 7000 years long 6+7Me-C17:0 record from the Bothnian Sea also suggests a relationship with the mean summer temperature in the Baltic Sea region, but at a multi-centennial to multi-millennial timescale. The intensity of the cyanobacterial blooms in the Baltic Sea is thus likely mainly related to natural processes such as temperature variability, at least at a multi-decadal to multi-millennial timescale.

scholarly journals Reconstructing N<sub>2</sub>-fixing cyanobacterial blooms in the Baltic Sea beyond observations using 6- and 7-methylheptadecane in sediments as specific biomarkers

2020 ◽  
Vol 17 (9) ◽  
pp. 2579-2591
Author(s):  
Jérôme Kaiser ◽  
Norbert Wasmund ◽  
Mati Kahru ◽  
Anna K. Wittenborn ◽  
Regina Hansen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Cyanobacterial Blooms ◽  
Phosphorus Loading ◽  
The Baltic Sea ◽  
Natural Processes ◽  
Baltic Sea Region ◽  
History Of ◽  
Diazotrophic Cyanobacteria ◽  
The Baltic

Abstract. Summer cyanobacterial blooms represent a threat to the Baltic Sea ecosystem, causing deoxygenation of the bottom water and the spread of the so-called dead zones. The history of the Baltic Sea cyanobacterial blooms is known from in situ and satellite observations since the early 1980s but is still not well understood. By comparing both weekly resolved sediment trap material and a well-dated sediment core from the eastern Gotland Basin with monitoring and satellite cyanobacterial data of the last ca. 35 years, it is shown here that 6- and 7-methylheptadecane lipids (expressed as 6+7Me-C17 : 0) may be potentially considered semiquantitative biomarkers for diazotrophic cyanobacteria, and more specifically for Nodularia spumigena. Using this organic proxy, it was thus possible to reconstruct the history of cyanobacterial blooms beyond the observational period with a resolution of 2–4 years since 1860. Cyanobacteria were constantly present but in relatively low abundance until 1920, when they started to alternate between periods with high and low abundance. Interestingly, there seems to be no significant increase in cyanobacterial abundance in the 1950s, when eutrophication and deoxygenation of the Baltic Sea increased considerably. While the early increase in cyanobacteria may be related to a small increase in phosphorus loading, decadal to multi-decadal fluctuations are likely related to variability in the Baltic Sea surface temperature and, ultimately, to the Atlantic Multi-decadal Oscillation. A 7000-year 6+7Me-C17 : 0 record from the Bothnian Sea also suggests a relationship with the mean summer temperature in the Baltic Sea region but at a multi-centennial to multi-millennial timescale. The intensity of the cyanobacterial blooms in the Baltic Sea is thus likely mainly related to natural processes such as temperature variability, at least at a multi-decadal to multi-millennial timescale.

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