Strong and stable environmental structuring of the zooplankton communities in interconnected salt ponds

Abstract

This study investigated assemblages of Copepoda and Artemia in saltern ponds and determined the main environmental factors affecting them. Copepoda and Artemia were collected from four ponds of varying salinity. Community composition was analyzed relative to environmental variables, with a focus on spatial and seasonal changes. We used a method called Costatis, which is particularly suited to analyze species and environmental data collected at the same sites and dates where the relationships between environmental conditions and composition of biological communities are strong and rather stable, which is the case in our system. The major structuring factors identified by Costatis were salinity and N:P ratio. Cyclopoida and Calanoida were associated with low salinity and low N:P ratios; Harpacticoida were associated with high salinity and high N:P ratios; and Artemia were associated with very high salinity and low N:P ratios. The distribution of these groups over the salinity gradient is in accordance with previous results; the influence of N:P ratio had not been identified before and may reflect specific environmental requirements of the taxa.