Trophic Ecology of Solar Salterns

Multi-pond solar salterns provide a range of environments with different salinities, from that of seawater up to sodium chloride saturation and sometimes even further. The two extremes provide one of the most common habitats in the world (seawater) and one of the most extreme habitats in the world (calcium and magnesium chloride saturated brines). This is particularly interesting for microbial ecology, since large organisms disappear early in the salinity gradient, and mostly or exclusively microbial communities are found at the highest salinities. Given these advantages, it is surprising how few studies on the ecology of saltern ponds have been carried out. Saltern ponds have been used to study biogeochemistry (Javor 1989), as models for ancient evaporitic environments (Orti-Cabo et al.1984), and as a source of halophilic and halotolerant microorganisms (Ventosa et al. 1982; Rodriguez-Valera et al. 1985; Litchfield et al. 1999; Anton et al. 2002). Ecological studies have been essentially descriptions of the peculiar organisms found at different salinities, with attention to their respective salinity ranges, but with little concern for quantitation of biomass and activities of these organisms (Noel 1984). Therefore, we have a reasonable knowledge of the biota of salterns and of the generally decreasing number of species as salinity increases, but most functional aspects remain unknown.