Institute of Oceanology BAS

Varna, Bulgaria

Institute of Oceanology BAS

Varna, Bulgaria
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Strong J.A.,University of Hull | Andonegi E.,Tecnalia | Bizsel K.C.,Izmir Institute of Technology | Danovaro R.,Marche Polytechnic University | And 12 more authors.
Estuarine, Coastal and Shelf Science | Year: 2015

There is an increasing demand for environmental assessments of the marine environment to include ecosystem function. However, existing schemes are predominantly based on taxonomic (i.e. structural) measures of biodiversity. Biodiversity and Ecosystem Function (BEF) relationships are suggested to provide a mechanism for converting taxonomic information into surrogates of ecosystem function. This review assesses the evidence for marine BEF relationships and their potential to be used in practical monitoring applications (i.e. operationalized).Five key requirements were identified for the practical application of BEF relationships: (1) a complete understanding of strength, direction and prevalence of marine BEF relationships, (2) an understanding of which biological components are influential within specific BEF relationships, (3) the biodiversity of the selected biological components can be measured easily, (4) the ecological mechanisms that are the most important for generating marine BEF relationships, i.e. identity effects or complementarity, are known and (5) the proportion of the overall functional variance is explained by biodiversity, and hence BEF relationships, has been established.Numerous positive and some negative BEF relationships were found within the literature, although many reproduced poorly the natural species richness, trophic structures or multiple functions of real ecosystems (requirement 1). Null relationships were also reported. The consistency of the positive and negative relationships was often low that compromised the ability to generalize BEF relationships and confident application of BEF within marine monitoring. Equally, some biological components and functions have received little or no investigation.Expert judgement was used to attribute biological components using spatial extent, presence and functional rate criteria (requirement 2). This approach highlighted the main biological components contributing the most to specific ecosystem functions, and that many of the particularly influential components were found to have received the least amount of research attention.The need for biodiversity to be measureable (requirement 3) is possible for most biological components although difficult within the functionally important microbes. Identity effects underpinned most marine BEF relationships (requirement 4). As such, processes that translated structural biodiversity measures into functional diversity were found to generate better BEF relationships.The analysis of the contribution made by biodiversity, over abiotic influences, to the total expression of a particular ecosystem function was rarely measured or considered (requirement 5). Hence it is not possible to determine the overall importance of BEF relationships within the total ecosystem functioning observed. In the few studies where abiotic factors had been considered, it was clear that these modified BEF relationships and have their own direct influence on functional rate.Based on the five requirements, the information required for immediate 'operationalization' of BEF relationships within marine functional monitoring is lacking. However, the concept of BEF inclusion within practical monitoring applications, supported by ecological modelling, shows promise for providing surrogate indicators of functioning. © 2015 Elsevier Ltd.

Arashkevich E.G.,RAS Shirshov Institute of Oceanology | Stefanova K.,Institute of Oceanology BAS | Bandelj V.,National Institute of Oceanography and Applied Geophysics - OGS | Siokou I.,Hellenic Center for Marine Research | And 5 more authors.
Journal of Marine Systems | Year: 2014

Coordinated cruises conducted in the Black Sea offshore waters in spring and autumn 2008, within the framework of European project SESAME, allowed the obtainment of a quasi-synoptic picture of the mesozooplankton standing stock and community composition. A clear spatial difference in total abundance was observed in spring with higher values over the slope than over the deep basin, due to the development of the fast boundary current. In autumn, standing stock was lower than in spring weakening of the boundary current and extensive eddy formation caused small-scale variability in mesozooplankton distribution and intensification of the exchange between the different parts of the sea. In both seasons, copepods comprised the bulk (62-95%) of mesozooplankton biomass. Community composition variability was tested for the first time using data obtained from the entire basin; the application of neural network analysis (Self-organizing Maps) revealed a rather homogenous picture of community composition. The development of cladocerans in autumn resulted in the differentiation of the slope areas from the deep basin. Mass development of the heterotrophic dinoflagellate Noctiluca scintillans was observed in the western and north-western areas in autumn. No change in standing stock values and community composition seem to have occurred since 2000 in the north-eastern region. © 2013 Elsevier B.V.

Perez-Dominguez R.,University of Hull | MacI S.,University of Hull | MacI S.,University of Salento | Courrat A.,IRSTEA | And 9 more authors.
Ecological Indicators | Year: 2012

Estuaries and lagoons are especially affected by anthropogenic pressures. This has resulted in symptoms of degradation including water quality impairment and loss of aquatic biota. Protection of aquatic biodiversity and management of these coastal systems require robust tools to assess habitat integrity. Fish populations have been extensively used to define habitat integrity in freshwater systems. Comparatively much less has been achieved in estuarine, lagoonal and related coastal systems classified as transitional systems under the European Water Framework Directive (WFD). The implementation of the WFD has prompted the rapid development of estuarine fish indices across Europe. In this context, this paper reviews seventeen published fish-based indices applied to estuarine systems worldwide and summarises common development strategies. Most indices are computed from a number of independent metrics and are based on assemblage composition or functional attributes of fish species (guilds). Among metric groups, species richness-composition metrics are the most widely used in current indices, followed by habitat guild, trophic guild, abundance and condition, and finally nursery function metrics. Within these, indicator species or guilds associated with estuarine quality features often dominate the indices. Development strategies vary but generally include (1) selection and calibration of metrics to anthropogenic pressure; (2) development of reference conditions; (3) comparison of metric values to reference ones; and (4) designation of thresholds for ecological status class. All index developers invest a large amount of effort on the definition and formulation of the reference values. Comparatively less effort is invested in the evaluation of the relevance and precision of the assessment. Only about half of the indices reviewed attempt any validation of the index outcomes and these are limited to simple correlation analysis and misclassification rate analysis by comparing index value with anthropogenic pressure proxies. Currently there are no European-wide consistent fish indices for transitional waters. Widening of the geographical relevance will require better precision in the formulation of reference conditions and greater inclusion of functional attributes in the indices. More recent transitional fish indices have paid increased attention to sampling method and effort, as well as metric sensitivity and robustness. This trend has continued parallel to the implementation of WFD-monitoring programmes across Europe. Further improvements are still needed to link pressures with index response and the characterisation of uncertainty levels in the index outcomes. © 2012 Elsevier Ltd. All rights reserved.

Stefanova K.,Institute of Oceanology BAS | Marinova V.,Institute of Oceanology BAS
International Journal of Applied Engineering Research | Year: 2015

Spatial distribution of zooplankton and Sound scattering layers (SSLs) were studied in the western Black Sea in October 2008. Acoustic backscatter measurements, net tow samples at discrete layers and Conductivity Temperature Depth (CTD) measurements from the upper 150 meters of the water column were carried out. In additional, the measurements of the fluorescence and dissolved oxygen were conducted. Zooplankton species were identified, enumerated, and measured. Two characteristics layers of sound scattering were found in the examination area. The SSLs performed diurnal vertical displacements. The migration speeds were estimated. The contribution of the species composition of zooplankton community to the SSLs was analysed. A clear horizontal pattern was outlined with the highest values of abundance in coastal and shelf area and decreasing trend toward the sea. The main type of vertical distribution regarding the position of the greatest zooplankton density was with maxima in surface waters, excluding the deepest station where maximum was at the thermocline layer. Generally, according the spatial vertical distribution the community in the upper mixed layer was dominated by copepods Acartia clausi, Paracalanus parvus and their larval stages, while Pseudocalanus elongatus and Calanus euxinus were concentrated at lower depths. Data of vertical distribution of net zooplankton community, SSLs and hydrological parameters of water column were compared and coupled. The study provides a brief example of utilization of acoustic techniques: i) to detect zooplankton community associated with the sound scattering layers and vertical stratification of the water column and ii) to indicate potential contribution to monitoring zooplankton standing stock. © Research India Publications.

St Raykov V.,Institute of Fishing Resources | Bikarska I.,Executive Agency for Fishery and Aquaculture | Panayotova M.,Institute of Oceanology BAS | Lisichkov K.,University of Macedonia
Journal of Environmental Protection and Ecology | Year: 2011

For proper fisheries management it is important to know fishing effort. One of the main problems in the Black Sea region is the lack of comprehensive information concerning the fishing activity, catch quantities and composition and how it affects the current state of fish stocks. We identified that the implementation of the fishing vessels monitoring system (VMS) is a powerful source of information regarding the fishing areas, fishing effort and also ensuring reliable fishing statistics. We are aware that in the Fisheries sector is really difficult to produce authoritative reports on the catch quantities and composition on annual principle, which means that we do not have a clear picture in this matter and the analysis of the current state of the stocks is with a fair approach to accuracy. The communication between responsible authorities and data exchange on regional level are not systematic.

Stanchev H.,Institute of Oceanology BAS | Palazov A.,Institute of Oceanology BAS | Stancheva M.,Institute of Oceanology BAS | Apostolov A.,Institute of Oceanology BAS
Geo-Eco-Marina | Year: 2011

Quantifying accurate coastline length is important for management applications, such as coastal classification/land cover use, erosion and environmental monitoring. However, due to the dynamic nature of the coastline, measuring its length with high accuracy has turned out to be a difficult research task. By far, different values of the Black Sea coastline length have been determined and these values range between 4020 km and 4500 km. Potential reasons for this could be mostly associated with various data sources and different methods applied. In this context, the study presents recent results for the Black Sea coastline length, which have been obtained during generation of the geo-data base at the IO-BAS. For this purpose, a number of 24 satellite images (Landsat 7) were used. Data processing and analysis were methodologically supported by GIS techniques for precise measurement of the coastline length. In addition, new results for the Black Sea total area were also obtained. © 2011, National Research and Development Institute for Marine Geology and Geoecology. All rights reserved.

Moncheva S.,Institute of Oceanology BAS | Pantazi M.,HCMR | Pautova L.,Russian Academy of Sciences | Boicenco L.,NIMRD Grigore Antipa | And 2 more authors.
Turkish Journal of Fisheries and Aquatic Sciences | Year: 2012

The quality of biological data has gained recognition as an essential part of international monitoring programmes, in response to the demand for strategic environmental evaluations such as the EU WFD, the MSFD and informed decisions for environmental sound management. The paper presents the results of an intercalibration exercise among four Black Sea phytoplankton laboratories (NIMRD-RO, IBSS-UKR, IO-RAS - RUS and IO-BAS - BLG) conducted under SESAME FP6 Project with the objectives: 1) to assess the degree of comparability of phytoplankton and chlorophyll a data produced by routine in-house methods; 2) to formulate recommendations for progress towards harmonization of the research methodology in the Black Sea. The statistical treatment of the results reveal that at the level of total phytoplankton abundance and biomass as well as chlorophyll a the data were in a good agreement, while for some taxonomic classes (Prymnesiophyceae and small flagellates) the differences were significant. The counted sample volume proves essential for detection of species diversity and the methods of species specific biovolume measurements - for the total biomass. As a follow up Guidelines for QC/QA of phytoplankton data and check-list with suggested shapes for biovolume calculation were produced under UP-Grade Black Sea SCENE FP7 Project that offer key options for progress. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey.

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