Relations between Environmentally Disturbing Establishments and three Invertebrate Indicator Species in the Baltic Sea

Abstract: In order to improve the knowledge about polluted areas in Sweden, Naturvårdsverket has compiled a list of all establishments and other anthropological activities, so called MIFOobjects, which emit harmful chemicals. Those activities which are placed on land might, depending on factors such as closeness to the sea, water solubility, degradability and toxicity of the chemicals have an impact on the biota in the Baltic Sea. In this study, spatial and statistical methods were used to explore potential relations between the abundance of three indicator organisms (Macoma balthica, Marenzelleria and Monoporeia affinis), closeness and a second variable built risk class of MIFO-objects and local environmental factors (e.g., sea depth, salinity) at the coast of Blekinge. The impact of MIFO-objects on the abundance of the indicator organisms was analyzed with both graphical and numerical multivariate analysis methods such as spearman analysis, principal component analysis and canonical component analysis. Four types of variables were created to enable the analysis. The first two variables were based one distance from emission locations to the study sites. The other pair of variables comprised on variable built on the cumulative risk assessment of the MIFO-objects given by Naturvårdsverket and another that was based on a classification of the emitted pollutants according to their chemical toxicity. The analysis showed that the abundance of Marenzelleria was positively correlated with MIFO-objects both in terms of risk assessment and chemical toxicity. This was probably a result of the fact that Marenzelleria is less sensitive to pollutants and therefore more competitive than other species in its habitat. Since the abundance of Macoma balthica covaried a lot with environmental factors such as salinity it was difficult to distinguish the impact of MIFO-object on the mussel. The statistical base of the abundance of Monoporeia affinis was too small to make any conclusions about what is describing the abundance.