INFLUENCE OF SPATIAL AND ENVIRONMENTAL FACTORS ON NANOPLANKTON IN LAKES: A LATITUDINAL STUDY BASED ON MORPHOLOGICAL SPECIES, FUNCTIONAL AND MOLECULAR DIVERSITY

IZAGUIRRE, IRINA; SAAD, JUAN; SCHIAFFINO, ROMINA; UNREIN, FERNANDO; ALLENDE, LUZ; SINISTRO, RODRIGO; SÁNCHEZ, MARÍA LAURA; VINOCUR, ALICIA; TELL, GUILLERMO

Congreso; ASLO 2013; 2013

We analysed the structure of the nano/microplankton in 45 freshwater environments across a latitudinal transect of more than 2100 km from Patagonia (45°S) to Maritime Antarctica (63°S) to determine the main factors that influence the community structure. The plankton diversity was analysed combining three different approaches: morphological species diversity, functional diversity and dominant molecular diversity (fingerprinting DGGE method). For phytoplankton we compared two functional classifications. The community structure was controlled by a combination of geographical and environmental factors. Multivariate analyses performed using both morphological species diversity and functional groups showed that the latitude was one of the main factors controlling community structure. The environmental factors associated with lake trophic status (Chl a, nutrients, DOC and Kd) determined differences among lakes located in a same region. We observed a significant increasing trend in the abundance of strictly autotrophic and heterotrophic organisms towards the higher trophic states of the lakes, but no clear pattern was observed in relation to mixotrophic species. Multivariate analyses based on molecular biodiversity also showed that both geographical (latitude and longitude) and local factors (nutrients) influenced the community structure.