engleski

Calcification on molluscs: Mussel Mytilus galloprovincialis as an indicator of marine environmental stress - A field study Project "Adriatic"

Monitoring programmes often involve organisms from different environments, such as estuarine and intertidal zones, where environmental conditions (e.g. salinity, temperature) do fluctuate and used biomarkers must distinguish effects of anthropogenic pollution from environmental stress. The main difficulty is the interference of natural environmental factors and pollution with the organism’ s biological responses depending on the specificity of used biomarker. When external conditions are closely controlled, biological responses can be accurately assessed and related to exposure events. In such cases, the use of biomarkers to monitor the health/pollution of the environment can be proposed. Mollusc shells are considered to be a powerful tool for monitoring environmental conditions and pollution also. For the “ Project Jadran” biomonitoring purposes we evaluated used species M. galloprovincialis and its carbon and oxygen isotopic composition in carbonate layer of shells (calcite, aragonite) as an indicator of environmental salinity (freshwater) stress at investigated sites along the entire Croatian Adriatic coast. The sites were ranged according to determined 18O and 13C values and then correlated with measured seawater salinity and temperature average values over the whole investigated period (1998-2007). Seawater salinity changes and thermal stress has been considered to be among the most important determinants (stressors) of organism distribution in the rocky intertidal zone. While salinity is relatively constant in the open Adriatic sea (cca 37 psu), it varies in intertidal zones, estuaries, close to under-sea fresh water springs and during rainy days in closed lagoons (10-37 psu). Due to the physical characteristics of seawater, the marine environment can be extremely stressful to its inhabitants. Salinity and temperature variations at investigated sites – costal areas from Lim channel to Dubrovnik (northern - southern Adriatic Sea) showed freshwater influence (environmental stress) which was reflected also in lower 13C and 18O values of mussel shell carbonates. According to our results we can separate 22 locations of investigated area into three groups: those with strong freshwater influence (6), those with minor freshwater influence (8) and those of marine environment (8). Data obtained from this study will provide a reference of environmental stress at investigated sites - Project Jadran, (coordinator Dr. N. Smodlaka) and for future bio-monitoring studies of waste management and marine environmental protection.

Mytilus galloprovincialis; Shell; Isotopic composition of carbon and oxygen; biomarkers; salinity; temperature; environmental condition variation; Adriatic Sea

nije evidentirano