Ecosystem processes: Litter breakdown patterns in mediterranean and black sea transitional waters

Leaf litter decomposition rates, in aquatic ecosystems, are known to be related to many different abiotic and biotic factors. Here, we focus on the influence of abiotic factors, searching for patterns of reed litter decay rates on gradient of physiographic, hydrological and physico-chemical components of transitional water ecosystems. Field experiments were carried out in 16 water ecosystems in the Eastern Mediterranean and Black Sea in spring 2005. Significant differences of leaf litter decomposition were observed among ecosystems along univariate gradient of tidal range, index of sinuosity, water temperature and salinity. At least 71% of variance in the litter breakdown rate was explained by the considered abiotic factors. It is concluded that, at the macro-ecological scale of study, some key abiotic factors, such as tidal range and salinity, are suggested to play a major role as drivers of plant detritus decomposition processes. The relevance of the described abiotic drivers as descriptor of the most commonly used classification schemes for transitional water ecosystems (i.e., Confinement and Venice System classifications), is a further support to their role as environmental forcing factors. © 2007 University of Salento.