Browsing by Subject "näytteenotto"

Environmental stress caused by heavy metal contamination of the sediment can threaten ecosystem functioning. Sediment macrofauna are often used to study the effects of environmental stress factors over time, as they are relatively sedentary and thus reflect the ambient conditions in an area. This study investigates whether heavy metal pollution influences the macrofaunal community adjacent to a former steel works factory in Koverhar, in the western Gulf of Finland. Various indices based on macrofaunal community composition and diversity are used in the Baltic Sea to evaluate the environmental status. This thesis evaluates the performance of three of these indices, Shannon-Wiener’s Index (H’), Benthic Quality Index (BQI) and Brackish water Benthic Index (BBI), in detecting the influence of heavy metal pollution on the marine environment. Two macrofaunal sampling methods, GEMAX corer and van Veen grab, are also compared to each other to investigate if there are differences in the structure of the macrofaunal communities that they capture. The study found that while there were indications of environmental stress, such as a lack of sensitive species and an abundance of tolerant species at the more heavily polluted stations, the heavy metal pollution could not be definitively proven to be the cause. H’ and BBI failed to find the differences potentially associated with heavy metal pollution between the stations, while BQI detected some of the differences found by the macrofaunal community analysis. The two sampling methods were found to not be significantly different from each other in terms of macrofaunal communities, but yielded significantly different macrofaunal index values, with the GEMAX results displaying a larger variance between replicates while the van Veen results were more consistent.