MODENUTTI Beatriz Estela
Balance between primary and bacterial production in North Patagonian shallow lakes.
BASTIDAS NAVARRO, M.,; MODENUTTI, BE; CRISTIANA CALLIERI; ROBERTO BERTONI; E BALSEIRO,
Año: 2009 vol. 43 p. 867 - 867
The shallow Andean North Patagonianlakes are suitable environments for the evaluation ofautotrophic and heterotrophic production under ascenario of high radiation in high dissolved organicmatter (DOM) systems. We aimed to study thebalance between primary and bacterial production inthree shallow Andean lakes, in a summer sampling(high irradiance condition). Our hypothesis is thattwo factors would interact: high light and high DOM,affecting bacteria and algae. We carried out experimentsof bacterial production (BP) by measuring[14C]-L-leucine incorporation and PP by 14C uptake intwo fractions: picophytoplankton and phytoplankton[2 lm. Cell abundance, chlorophyll a, nutrients,DOM, light, and temperature were also measured.The contribution of picophytoplankton to total primaryproduction (PP) was, in general, very highexceeding 50%. Picophytoplankton was photosyntheticallymore efficient than the larger autotrophs in alllakes. We observed a decrease in PP at surface levelsdue the high solar irradiances, while BP was notaffected. Changes in the PP:BP ratios were observedin relation to DOM content and light effect. Our dataindicate that the amount of available DOM drives thebalance between PP and BP. However, solar radiationshould be included as an important factor sincePP:BP ratio may decrease because of PPphotoinhibition.