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.

Stages of the Baltic Sea evolution in the geochemical record and radiocarbon dating of sediment cores from the Arkona Basin

2014 ◽  
Vol 43 (3) ◽  
Author(s):  
Robert Kostecki
Keyword(s):  
Baltic Sea ◽  
Environmental Changes ◽  
Sediment Cores ◽  
Late Glacial ◽  
Sudden Increase ◽  
The Baltic Sea ◽  
Geochemical Composition ◽  
Arkona Basin ◽  
The Baltic ◽  
Ancylus Lake

AbstractFour sediment cores from the southern part of the Arkona Basin were analyzed in terms of their geochemical composition, age and stratigraphy. The main stages of the Baltic Sea: the Baltic Ice Lake, the Ancylus Lake and the Littorina Sea were identified in all the analyzed cores. The data confirmed the high water fluctuation and significant environmental changes during the Baltic Sea evolution in the Late-Glacial and the Holocene. The signs of the second regression of the Baltic Ice Lake, dated at around 11 000 cal BP, were identified at a depth of 24 m b.s.l. Regression of the Ancylus Lake, dated at 9300 cal BP, was identified at a depth of 23 m b.s.l. The most pronounced period was the transition stage between the Ancylus Lake and the Littorina Sea. The record of the Littorina Sea onset in the sediments of the Arkona Basin is marked as a sudden increase in loss on ignition, biogenic silica, magnesium, calcium, iron and strontium. The age of the Littorina Sea in the Arkona Basin was estimated as younger than 8200 cal BP.

scholarly journals Developing benthic monitoring programmes to support precise and representative status assessments: a case study from the Baltic Sea

2020 ◽  
Vol 192 (12) ◽  
Author(s):  
Henrik Nygård ◽  
Mats Lindegarth ◽  
Alexander Darr ◽  
Grete E. Dinesen ◽  
Ole R. Eigaard ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Marine Ecosystem ◽  
Monitoring Data ◽  
Data Series ◽  
Sampling Effort ◽  
The Baltic Sea ◽  
Basin Scale ◽  
The Status ◽  
The Baltic

AbstractBenthic habitats and communities are key components of the marine ecosystem. Securing their functioning is a central aim in marine environmental management, where monitoring data provide the base for assessing the state of marine ecosystems. In the Baltic Sea, a > 50-year-long tradition of zoobenthic monitoring exists. However, the monitoring programmes were designed prior to the current policies, primarily to detect long-term trends at basin-scale and are thus not optimal to fulfil recent requirements such as area-based periodic status assessments. Here, we review the current monitoring programmes and assess the precision and representativity of the monitoring data in status assessments to identify routes for improvement. At present, the monitoring is focused on soft-bottoms, not accounting for all habitat types occurring in the Baltic Sea. Evaluating the sources of variance in the assessment data revealed that the component accounting for variability among stations forms the largest proportion of the uncertainty. Furthermore, it is shown that the precision of the status estimates can be improved, with the current number of samples. Reducing sampling effort per station, but sampling more stations, is the best option to improve precision in status assessments. Furthermore, by allocating the sampling stations more evenly in the sub-basins, a better representativity of the area can be achieved. However, emphasis on securing the long-term data series is needed if changes to the monitoring programmes are planned.

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.

scholarly journals Local Environmental Conditions Shape Generalist But Not Specialist Components of Microbial Metacommunities in the Baltic Sea

2016 ◽  
Vol 07 ◽  
Author(s):  
Markus V. Lindh ◽  
Johanna Sjöstedt ◽  
Michele Casini ◽  
Agneta Andersson ◽  
Catherine Legrand ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Environmental Conditions ◽  
The Baltic Sea ◽  
The Baltic

scholarly journals Distribution, abundance and environmental conditions of the clonal aquatic fern Salvinia natans (L.) All. in the Vistula delta (Baltic Sea Region)

2012 ◽  
Vol 28 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Agnieszka Gałka ◽  
Józef Szmeja
Keyword(s):  
Baltic Sea ◽  
Environmental Conditions ◽  
Vistula Lagoon ◽  
Alkaline Ph ◽  
The Baltic Sea ◽  
Aquatic Fern ◽  
Baltic Sea Region ◽  
Salvinia Natans ◽  
The Baltic ◽  
Vistula Delta

Abstract We examined the distribution, resources and environmental conditions of the clonal aquatic fern Salvinia natans (L.) All., expansive in the Vistula delta (N Poland). Before 2006, there were 7 stands of this species, while in the years 2006-2010 their number increased to 21. The most abundant populations were found in the rivers: Tuga (133.0±37.6 indiv./0.1 m2), Fiszewka( 79.3±6.0), Szkarpawa (74.7±5.0), Struga Orłowska (61.0±2.0), Nogat (52.3±2.5), Elbląg (40.3±31.8), Wiślano-Zalewowy Canal (61.3±3.2) and in the SW part of Lake Druzno (72.3±2.5). S. natans did not colonise the weakly saline Vistula Lagoon and Elbląg Bay, which belong to the Baltic Sea. The plant under study occurred in shallow (2.2±1.5 m), narrow (17.9±13.6 m), slow-flowing (0.11±0.12 m s-1) and fertile (4.7±4.2 mg TN dm-3, 0.7±0.4 mg TP dm-3) watercourses. The water in them had neutral or alkaline pH (7.2-9.2) and was weakly saline (53.8±21.3 mg Cl dm-3). A dense mat of S. natans significantly affected the environmental conditions in the watercourses: water oxygenation, PAR intensity and concentration of biogenic substances, especially phosphorus, decreased.

scholarly journals Assessing proxy signatures of temperature, salinity, and hypoxia in the Baltic Sea through foraminifera-based geochemistry and faunal assemblages

2018 ◽  
Vol 37 (2) ◽  
pp. 403-429 ◽  
Author(s):  
Jeroen Groeneveld ◽  
Helena L. Filipsson ◽  
William E. N. Austin ◽  
Kate Darling ◽  
David McCarthy ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Environmental Changes ◽  
Environmental Parameters ◽  
The Baltic Sea ◽  
Traditional Use ◽  
Geochemical Composition ◽  
Faunal Assemblages ◽  
The Past ◽  
Hypoxic Conditions ◽  
The Baltic

Abstract. Current climate and environmental changes strongly affect shallow marine and coastal areas like the Baltic Sea. This has created a need for a context to understand the severity and potential outcomes of such changes. The context can be derived from paleoenvironmental records during periods when comparable events happened in the past. In this study, we explore how varying bottom water conditions across a large hydrographic gradient in the Baltic Sea affect benthic foraminiferal faunal assemblages and the geochemical composition of their calcite tests. We have conducted both morphological and molecular analyses of the faunas and we evaluate how the chemical signatures of the bottom waters are recorded in the tests of several species of benthic foraminifera. We focus on two locations, one in the Kattegat (western Baltic Sea) and one in Hanö Bay (southern Baltic Sea). We show that seawater Mn∕Ca, Mg∕Ca, and Ba∕Ca (Mn∕Casw, Mg∕Casw, and Ba∕Casw) variations are mainly controlled by dissolved oxygen concentration and salinity. Their respective imprints on the foraminiferal calcite demonstrate the potential of Mn∕Ca as a proxy for hypoxic conditions, and Ba∕Ca as a proxy for salinity in enclosed basins such as the Baltic Sea. The traditional use of Mg∕Ca as a proxy to reconstruct past seawater temperatures is not recommended in the region, as it may be overprinted by the large variations in salinity (specifically on Bulimina marginata), Mg∕Casw, and possibly also the carbonate system. Salinity is the main factor controlling the faunal assemblages: a much more diverse fauna occurs in the higher-salinity (∼32) Kattegat than in the low-salinity (∼15) Hanö Bay. Molecular identification shows that only Elphidium clavatum occurs at both locations, but other genetic types of both genera Elphidium and Ammonia are restricted to either low- or high-salinity locations. The combination of foraminiferal geochemistry and environmental parameters demonstrates that in a highly variable setting like the Baltic Sea, it is possible to separate different environmental impacts on the foraminiferal assemblages and therefore use Mn∕Ca, Mg∕Ca, and Ba∕Ca to reconstruct how specific conditions may have varied in the past.

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