Relationship between phytoplankton and bacterioplankton production in vegetated humic shallow lakes

ALEX AGUILAR ZURITA; PATRICIA RODRÍGUEZ

ECOLOGÍA AUSTRAL

ASOCIACIÓN ARGENTINA DE ECOLOGÍA

Lugar: Buenos Aires; Año: 2016 vol. 26 p. 305 - 310

0327-5477

In this study, we show that depth-integrated pelagic primary production (PP) can exceed bacterioplankton production (BP) in vegetated humic shallow lakes, giving as a result an autotrophic water column despite light restrictions and availability of organic carbon for lake bacteria. Intuitively, these conditions should favor the development of a heterotrophic water column. Instead, during our survey, BP represented between 1.3 to 5 % of PP most of the time and once, during late summer, BP was ca. 71 % of PP. Although we cannot conclude about the mechanisms behind the observed results, previous surveys and experimentation in the wetland allow us to hypothesize that autotrophic conditions were favored by, i) the shallow nature of the lakes which compensates for light attenuation by organic matter when integrating production in the water column; ii) the presence of anaerobic anoxygenic photosynthetic bacteria below the macrophyte cover and, iii) high predation rates on bacterioplankton by heterotrophic flagellates below the floating plants.