Browsing by Subject "the Baltic Sea"
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(2018)In this Master’s thesis, microplastic (<5 mm) ingestion by coastal fish in Finland was investigated. Fish were caught at nine locations on the coast of Finland. Water samples were taken at seven locations. The research questions were: How much microplastics are there in coastal fish in Finland? Are there differences in the frequency of microplastic ingestion by fish between different locations or species? Is there a relationship between the size of the fish and the presence of ingested plastic particles? Is there a relationship between the stomach fullness and the presence of ingested plastic particles? Does the frequency of microplastic ingestion by fish correlate with the amount of microplastics in seawater in the same locations? The gastrointestinal tracts of 503 fish were analysed. Microplastics were found in 40 fish (8 %). The frequency of fish with plastic was significantly higher in Kivinokka, Helsinki than in other locations studied. No relationship was found between the size or the species of the fish and the presence of ingested plastic particles. Also, no relationship was found between the stomach fullness and plastic ingested. There was no correlation between the frequency of microplastic ingestion by fish and the amount of microplastics in seawater. The results of the thesis were compared to previous research results from the open sea areas of the northern Baltic Sea. The comparison suggests that the ingestion of microplastics is more common in coastal fish in Finland than in the open water fish in the northern Baltic Sea. This thesis provides the first published record of plastic particles in the gastrointestinal tracts of coastal fish in Finland. Long-term studies are recommended in order to confirm the results.
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(2024)Climate change has caused a vital need to identify the coastal ecosystems with high carbon sequestration capacity, i.e. Blue Carbon ecosystems. The ability of these ecosystems to sequester carbon is strongly influenced by the physical environment. However, previous research on Blue Carbon potential of coastal macrophyte ecosystems has mainly focused on single seagrass species whereas research on multispecies meadows along environmental gradients, such as wave exposure has been scarce. Nonetheless, exposure and depth are known to shape the functional structure of macrophyte communities. The aim of this study was to investigate if exposure and depth affect the functional structure and biomass-bound carbon stocks of macrophyte communities along an exposure gradient in an archipelago area in the western Gulf of Finland, northern Baltic Sea. Macrophyte samples were collected at two different depths (1-2 m and 3-4 m) from 20 soft-bottom sites with different exposure levels. At each site, the functional community structure was quantified by measuring four functional traits (maximum height, root depth, root-to-shoot ratio, specific leaf area), associated with the variation in plant life history strategies and in addition, the plant biomass-bound carbon was determined. The results showed that when moving from the outer to the inner archipelago, the species composition shifted from marine to limnic species, and the community functional structure was shaped by environmental conditions (i.e. wave exposure, light availability, salinity) and depended on the depth. The plant carbon stocks did not differ significantly along the exposure gradient in the shallow areas, while at increasing depth, exposed sites had the highest plant carbon stocks, which can be likely explained with the environmental factors such as light availability. To conclude, these results highlight the need for further research that investigates the connection between environmental drivers, functional traits, and plant carbon stocks to assess the Blue Carbon potential of multispecies macrophyte communities in heterogenous environments.
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