Search results for "Water-level fluctuations"
showing 3 items of 3 documents
Phytoplankton colonization patterns. Is species richness depending on distance among freshwaters and on their connectivity?
2015
Phytoplankton assemblages in two Sicilian water bodies were compared to test the hypothesis that colonization events and the successful establishment of a new species in an aquatic ecosystem may depend on the number of water bodies in a given area and on their relative distance. The two ecosystems are both natural, shallow lakes and they are protected sites hosting a rich avifauna. Lake Biviere di Gela is located in an area with a high density of ponds, whereas Lake Pergusa is an isolated waterbody without other aquatic ecosystems in its surroundings. Both lakes had almost disappeared about 10 years ago because of the over-exploitation of their main inflows. They were therefore re-filled us…
Phytoplankton dynamics and structure: a comparative analysis in natural and man-made water bodies of different trophic state
2000
Previous investigations on Sicilian man made lakes suggested that physical factors, along with the specific morphology and hydrology of the water body, are important in selecting phytoplankton species. In particular, the variations of the zmix/zeu ratio due to the operational procedure to which reservoirs are generally subject were recognised as a trigger allowing the assemblage shift. To investigate if these variations may be considered analogous to those occurring in natural lakes as trophic state and phytoplankton biomass increase, causing a transparency decrease and a contraction of the euphotic depth, phytoplankton were collected in two natural water bodies, one mesotrophic (Lake Bivie…
Mediterranean Climate and Eutrophication of Reservoirs: Limnological Skills to Improve Management
2011
Sicily is the largest Mediterranean island and one of the most densely populated areas in the region. To counteract the periodic oscillation in water availability and fulfill drinking and agriculture needs, about 30 dam-reservoirs, impounding in total 750 106 m3, were built in the last 60 years. However, the inherent features of the Mediterranean climate and the total lack of awareness from local authorities have contributed to a progressive increase in the trophic state of these human-made lakes. In particular, the water is stored during the winter rainy season and then it is intensively used in the dry summer. These operational procedures, in particular the time separation between filling…