Spatio-temporal patterns of the Microphytoplankton community structure and distribution in a North African lagoon

The spatio-temporal variability of the mircophytoplankton community was investigated in the oualidia lagoon (atlantic-morocco). microphytoplankton structure,composition and distribution were analyzed at six sampling stations during an annual cycle (from june 2011 to may 2012),based on phytoplankton net and bottle samples. a total of 126 taxa belonging to 2 divisions were identified,including bacillariophyceae (80 taxa) and dinophyceae (46 taxa). the highest species richness (57 taxa) was found in the central zone of the lagoon (whereas the lowest one (41 taxa) was recorded in the most distal to the sea inlet station). the highest mircophytoplankton abundance (2.82 x 105cells l-1) and the lowest (1.53 x 105cells l-1) were measured respectively at the most distal and proximal to the sea inlet stations. the values of h' and j' index showed that the microphytoplankton community never reached a situation of monospecificity and was in equilibrium at the entire lagoon. a diversity model (dimo) distinctly separated the winter microphytoplankton populations from spring,summer and autumn microphytoplankton populations. the transition from the first to the second group was accompanied by an increase in species richness,diversity and evenness. the rank-frequency diagram revealed the mature character of microphytoplankton populations and thus characterized a stable environment in oualidia lagoon.