STRONG LINKS BETWEEN DOM AND MICROBIAL COMMUNITIES IN A SOUTH ATLANTIC COASTAL AREA (EL RINCÓN, ARGENTINA)

JOHN E. GARZÓN CARDONA; CECILIA ALONSO; ANA MARÍA MARTÍNEZ; SILVIO PANTOJA; CAROLA FERRONATO; VALERIA GUINDER; RUBÉN HUGO FREIJE; RUBÉN J. LARA

Granada

Congreso; Aquatic Sciences Meeting, Aquatic Sciences: Global And Regional Perspectives ? North Meets South; 2015

In this study, we analyzed the composition of dissolved organic matter (DOM) as concentration of free and combined amino acids and carbohydrates (Biochemical-DOM) and its fluorescence properties (CDOM), in relation to the abundance of phytoplankton and the major aquatic bacterial groups in a coastal area. Three zones were defined according to CDOM and inorganic nutrients distribution, which showed North to South and coast to open waters decreasing trends. Biochemical-DOM accounted for one fourth of the total DOM, being combined amino acids the dominant fraction. Aspartic acid, arginine, alanine, valine and leucine represented 43% of amino acids (AAs) and correlated significantly with microphytoplankton abundance (MA). Polysaccharides correlated with MA but only in the transition and open ocean zones; in the coastal zone they correlated with river input. The main bacterial groups appeared differently associated to the Biochemical-DOM components e.g. Gammaproteobacteria correlated highly significantly with AAs while Alphaproteobacteria and Betaproteobacteria correlated with monosaccharides and polysaccharides. The strong relationships between the Biochemical-DOM and the planktonic communities, as well as with the allochthonous input, sheds light on the DOM origin and transformations in this area.