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Fleming-Lehtinen V.,Marine Research Center | Laamanen M.,Helsinki Commission
Estuarine, Coastal and Shelf Science | Year: 2012

Secchi depth, as a proxy of water transparency, provides valuable information on the availability of light to the underwater ecosystems. Changes in water transparency have also been widely linked to eutrophication and phytoplankton biomass. This study aimed to describe the development of water transparency in the Baltic Sea through a unique century-long set of Secchi depth observations. Furthermore, the aim was to explain the role of phytoplankton in determining water transparency in these optically complex waters. Water transparency in the open Baltic Sea has decreased during the last one hundred years. The development differs between the sub-basins of the Baltic Sea. The decrease has been most profound in the north-eastern Baltic sub-basins, but apparent also in parts of the Southern and Central Baltic. In many of the northern areas the decrease has accelerated during the last decades, whereas in the Southern Baltic a recent increase was observed. The analysis of simultaneous chlorophyll . a observations during the period from 1972 to 2006 revealed that during summer time, 13-17% of the light attenuation can be attributed to phytoplankton. In spring, the average proportion is between 31 and 42%, with great variation between observations. We find Secchi depth a suitable indicator of eutrophication, integrating various organic matter related features. It should always be applied with sufficient background information of the optical properties of the water mass, and complemented by other indicators. © 2012 Elsevier Ltd.

Ranft S.,University of Vechta | Pesch R.,University of Vechta | Schroder W.,University of Vechta | Boedeker D.,German Federal Agency for Nature Conservation | And 2 more authors.
Marine Pollution Bulletin | Year: 2011

Concerning increased degradation of marine ecosystems, there is a great political and institutional demand for an array of different tools to restore a good environmental status. Thereby, eutrophication is acknowledged as one of the major human induced stressors which has to be monitored and reduced. The present study concentrates on an assessment of the eutrophication status of the Baltic Sea Protected Areas by use of available data and GIS technologies. Two geodata layers were used for analysis: (1) a map on the eutrophication status of the Baltic Sea generated by the Helsinki Commission applying the HELCOM Eutrophication Assessment Tool (HEAT), and (2) modelled data on atmospheric nitrogen deposition made available by the European Monitoring and Evaluation Programme (EMEP). The results yielded comprehensive and conclusive data indicating that most of the BSPAs may be classified as being 'affected by eutrophication' and underlining the need to decrease the overall emissions of nutrients. © 2011 Elsevier Ltd.

Korpinen S.,Helsinki Commission | Meski L.,Helsinki Commission | Andersen J.H.,University of Aarhus | Andersen J.H.,National Center for Environment and Energy | Laamanen M.,Helsinki Commission
Ecological Indicators | Year: 2012

The EU Marine Strategy Framework Directive requires Member States to estimate the level of human impacts on their marine waters. We report the first attempt to quantify the magnitude and distribution of cumulative impacts of anthropogenic pressures for an entire regional sea, the Baltic Sea. We used a method which takes account of the sensitivity of different ecosystem components and gives scores for potential impacts in 5 km × 5 km areas. Our quantification of impacts was based on data layers of anthropogenic pressures and ecosystem components. The classification of the anthropogenic pressures follows the MSFD and the outcome of the index was targeted to facilitate the implementation of the directive. The study presents the cumulative impacts over the entire sea area and shows that the highest estimated impacts were in the southern and south-western sea areas and in the Gulf of Finland. The lowest index values were found in the Gulf of Bothnia. The results coincide with the population densities of the adjacent catchment areas. Fishing, inputs of nutrients and organic matter and inputs of hazardous substances comprised 25%, 30% and 30%, respectively, of the total cumulative impact. The approach used is transparent and the results are useful in regard to ecosystem-based management, e.g. for area-based management and assessments. Examples of uses are given together with analysis of the strengths and weaknesses of the approach. © 2011 Elsevier Ltd. All rights reserved.

Korpinen S.,Helsinki Commission | Meidinger M.,Helsinki Commission | Laamanen M.,Helsinki Commission
Marine Pollution Bulletin | Year: 2013

The European seas are under anthropogenic pressures impacting the state of water quality, benthic habitats and species. The EU Marine Strategy Framework Directive (MSFD) requires the Member States to assess the impacts of pressures and make a programme of measures leading to good environmental status (GES) by 2020. This study presents a method for assessing the quantity and distribution of anthropogenic impacts on benthic habitats in the Baltic Sea by using spatial data of human pressures and benthic habitats. The southern sub-basins were more extensively impacted than the northern sub-basins. Over the entire sea area, deep sea habitats were more impacted than shallower infralittoral and circalittoral habitats. Sand and coarse sediments were the seabed types relatively most impacted in the Baltic Sea scale. A comparison against tentative thresholds for GES showed that in the sub-basin scale only one third of the habitat types was in GES. © 2013 Elsevier Ltd.

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