| Abstract [eng] |
This dissertation is based on a reconstruction of the food web in the Lithuanian Baltic Sea coastal zone. The results provide a possibility to evaluate the role of various organisms, including seasonally present fishes and waterbirds, and on the ecosystem functioning in general. Analysis of stable carbon and nitrogen isotope ratios revealed the contribution of the Curonian lagoon outflow to the food web compartments along the coastal zone. Moreover, stable sulfur isotope ratios were proved to serve as an effective supplement to stable carbon and nitrogen isotope ratio analysis for trophic studies in the coastal Baltic ecosystem, including diet assessment of wintering marine birds. The ECOPATH food web model revealed the structure of the coastal zone for the period of 2000-2010. The model results indicated net heterotrophy of the coastal ecosystem and allowed to estimate organic matter flows. The most important functional groups are piscivorous birds, pike-perch, nectobenthos and mesozooplankton. Relationship between stable nitrogen isotope ratios of consumers and trophic levels estimated by the ECOPATH model confirmed the relevance of both methods applied to the analysis of the Baltic Sea coastal zones. |
