Assessment of the Typology and the Trophic Status of Two Mediterranean Lake Ecosystems in Northwestern Greece

The objective of this study is the assessment of the typology and the trophic relevant water quality parameters in two Mediterranean lakes (Lake Ziros and Lake Kastoria) under the view of the WFD. Lake types were identified based on characteristics specified in Annex II of the WFD, while trophic indexes (OECD, TSI Carlson) were used in order to assess their trophic status. A modified TSI index appropriate for warmer lakes was also applied. According to our results, Lake Kastoria is classified as eutrophic lake with a tendency to hypertrophication while Lake Ziros is a mesotrophic ecosystem with clear signals of eutrophication. Both ecosystems are considered "at risk" of not fulfilling the WFD environmental objectives due to the existence of certain anthropogenic pressures

Assessing the zooplankton community and environmental factors in a Mediterranean wetland

Mediterranean wetlands represent unique repositories of biodiversity, but these ecosystems are increasingly threatened by human-induced habitat loss. Seventy percent of Greek wetlands (ponds, mires, marshes, etc.) have been lost in the past 80 years due to human intervention. In Greece habitat types of mires, listed in Directive 92/43/EEC, have been recorded in a few locations, one of the most important is Kalodiki wetland. Eutrophication key elements were determined at four sampling stations throughout 1 year in order to monitor the trophic conditions. Moreover, the zooplankton community was described as biological element relevant in the assessment of the ecological status of Kalodiki wetland. Kalodiki wetland exhibits nutrient concentrations corresponding to eutrophic conditions while according to chlorophyll-a values it is classified between mesotrophic and eutrophic status depending mostly on the sampling period. As concerning zooplankton community, it appears poor in species and dominated by small-sized organisms, which is generally typical of eutrophic, disturbed systems. Differences among zooplankton assemblages over seasons as well as among sampling sites highlight the role of both abiotic and biotic factors

Assessment of microcystin distribution and biomagnification in tissues of aquatic food web compartments from a shallow lake and evaluation of potential risks to public health

The objectives of this study were: (1) to examine the distribution and bioaccumulation of microcystins in the main components of the food web (phytoplankton, zooplankton, crayfish, shrimp, mussel, snail, fish, frog) of Lake Pamvotis (NW Greece), (2) to investigate the possibility of microcystin biomagnification and (3) to evaluate the potential threat of the contaminated aquatic organisms to human health. Significant microcystin concentrations were detected in all the aquatic organisms during two different periods, with the higher concentrations observed in phytoplankton and the lower in fish species and frogs. This is the first study reporting microcystin accumulation in the body of the freshwater shrimp Atyaephyra desmsaresti, in the brain of the fish species common carp (Cyprinus carpio) and in the skin of the frog Rana epirotica. Although there was no evidence for microcystin biomagnification, the fact that microcystins were found in lake water and in the tissues of aquatic organisms, suggests that serious risks to animal and public health are possible to occur. In addition, it is likely to be unsafe to consume aquatic species harvested in Lake Pamvotis due to the high-concentrations of accumulated microcystins