AbstractsBiology & Animal Science

Biomarkers measured in organisms are sensitive molecular, cellular or individual level biological effects, which can be applied as early-warning signals of environmental contamination before damage occurs at population, community or ecosystem levels. In this thesis, a suite of biomarkers and tissue concentrations of chemicals were measured in mussels (Mytilus trossulus) as indicators of environmental pollution. The mussels were transplanted in specially made cages in coastal areas of the northern Baltic Sea influenced by different types of contamination and environmental factors. The aims of the research were to apply the biomarker approach to (1) assess the impact of contaminants on the health status of mussels, (2) investigate the effects of seasonal variability in biotic and abiotic factors, and low salinity, and (3) validate the usefulness of the mussel caging method for biomonitoring of chemical contamination in the northern Baltic Sea. The results showed marked biomarker responses coinciding with higher concentrations of contaminants, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), organotins and trace metals, in mussels caged at the most contaminated study sites. At the contaminated sites, for example the enzymatic biomark¬ers of the antioxidant defense system indicated higher stress level, which was closely linked to elevated level of DNA-damage, increased biotransformation activity and decreased general health status of the cells. Biomarker responses and tissue contaminant concentrations were also related to the seasonal variability in growth and especially in soft tissue weight of the mussels. In the northern Baltic Sea the mussels almost fully deplete their energy stores during the winter; in the spring mussels efficiently feed on the fresh phytoplankton, which forms the main source of energy for their reproduction, energy metabolism and growth. Natural environmental factors caused less variation in the biomarker responses in the late summer and autumn suggesting that this time period is the most suitable for studying contaminant induced effects in mussels. More pronounced effects were observed in mussels exposed jointly to low salinity and chemical contamination, indicating that increased environmental stress reduces the tolerance of mussels towards anthropogenic pressures. This work showed that the mussel caging approach is an efficient biomonitoring method to assess biological effects and tissue accumulation of complex mixtures of contaminants as long as the effects of seasonal variability and low salinity are taken into account. Mereen jatkuvasti päätyvät sekä siellä jo olevat haitalliset kemikaalit huonontavat eliöiden terveyttä. Tässä työssä tutkittiin useita eliöiden terveydentilasta kertovia muuttujia eli ns. biomarkkereita ja haitallisten aineiden kudospitoisuuksia pohjoisen Itämeren sinisimpukoista Turun, Porvoon, Helsingin, Gävlen ja Sundsvallin kaupunkien edustalla. Tutkimuksessa käytettiin…