Phytoplankton composition and dynamics in three shallow temporary salt lakes (Monegros, Spain)

The present study deals with phytoplankton composition and dynamics of three ephemeral saline lakes (La Muerte, Pinol and Sulfu rica) situated in one of the most arid inland zone in Europe (Los Monegros). The lakes show marked differences among one another, although they are all temporary, shallow and saline systems (>30 g l^-1). La Muerte is dominated by microbial mats that are absent from the other two. Pinol is more exposed to strong winds than the other two lakes and exhibits higher turbidity. Sulfu rica appears to be the most extreme system, with the highest salinity, which leads to a complete absence of macrozooplankton. Phytoplankton composition in these lakes varies as a consequence of the different physico-chemical conditions; it is fundamentally composed of typical hypersaline species such as Dunaliella sp., Aphanothece sp., and soil benthic species (e.g. Hantzschia amphyoxis) that appear to play an important role in these systems. Comparative analysis of the microbial component (phytoplankton diversity and temporal evolution) under in situ conditions and the presence of various abiotic and biotic factors, including the impact of macrozooplankton grazing, shows that it is easy to overlook large differences in the community structure of apparently similar ecosystems. The present study is a contribution to the understanding of the often-neglected microbial ecology of ephemeral shallow lakes.

Keywords: Taxonomy; Microalgae; Population dynamics; Hypersaline shallow lakes;Dunaliella sp;Aphanothece sp;Hantzschia amphyoxis;macrozooplankton;Phytoplankton;taxonomy.

Corresponding author: Tel.: +3491 497 80 10; fax: +3491 497 80 01

E-mail: carmen.guerrero@uam.es (M.C. Guerrero)