MODENUTTI Beatriz Estela
Environmental changes affecting light climate in oligotrophic mountain lakes: the Deep Chlorophyll Maxima as a sensitive variable
B. MODENUTTI, ; E. BALSEIRO,; BASTIDAS NAVARRO, M.,; C. LASPOUMADERES,; M. S. SOUZA,; F. CUASSOLO,
BIRKHAUSER VERLAG AG
Lugar: BASEL; Año: 2013 vol. 75 p. 361 - 361
Abstract The North-Patagonian Andean lakes ofArgentina are high light, low nutrient environments thatexhibit development of deep chlorophyll maxima (DCM)at the metalimnetic layer during summer stratification, atapproximately 1 % of surface PAR irradiance. We examinedwhether the position of DCM changes as aconsequence of long-time (global warming: glacial clayinput) and short-time (eruption: volcanic ashes) events. Weperformed different field studies: (1) an interlacustrineanalysis of six lakes from different basins, including data ofthe 2011 volcanic eruption, which caused an unexpectedvariation in water transparency; and (2) an intralacustrineanalysis in which we compared different stations along atransparency gradient in Lake Mascardi caused by glacialclay input at one end of the gradient. In these analyses, wedocumented changes in DCM depth and its relationshipwith different parameters. DCM development was notrelated with thermocline depth or nutrient distribution. Inall cases, the only significant variables were Kd 320 nmand Kd PAR. Our study showed that suspended particles(glacial clay and volcanic ashes) can play a crucial role intransparent lakes, affecting lake features such as thephototrophic biomass distribution along the water column.Suspended solid inputs from either glacial clay or volcanicashes produce a comparable effect, provoking a decrease inlight and, consequently, an upper location of the DCM.Thus, the DCM position is highly sensitive to globalchanges, such as increased temperatures causing glacierrecession or to regional changes caused by volcaniceruptions.