Inorganic mercury (Hg2+) uptake by different plankton fractions of Andean Patagonian lakes (Argentina)

E3S Web of Conferences. 2014;1:41018 DOI 10.1051/e3sconf/20130141018

 

Journal Homepage

Journal Title: E3S Web of Conferences

ISSN: 2267-1242 (Online)

Publisher: EDP Sciences

LCC Subject Category: Geography. Anthropology. Recreation: Environmental sciences

Country of publisher: France

Language of fulltext: French, English

Full-text formats available: PDF

 

AUTHORS

Diéguez M.C. (Laboratorio de Fotobiología, Instituto de Biodiversidad y Medioambiente, CONICET-Universidad Nacional del Comahue)
Soto Cárdenas C. (Laboratorio de Fotobiología, Instituto de Biodiversidad y Medioambiente, CONICET-Universidad Nacional del Comahue)
Ribeiro Guevara S. (Laboratorio de Análisis por Activación Neutrónica, Centro Atómico Bariloche)
Marvin DiPasquale M. (U.S. Geological Survey)
Gerea M. (Laboratorio de Fotobiología, Instituto de Biodiversidad y Medioambiente, CONICET-Universidad Nacional del Comahue)
Arribére M. (Laboratorio de Análisis por Activación Neutrónica, Centro Atómico Bariloche)
Queimaliños C.P. (Laboratorio de Fotobiología, Instituto de Biodiversidad y Medioambiente, CONICET-Universidad Nacional del Comahue)

EDITORIAL INFORMATION

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Time From Submission to Publication: 6 weeks

 

Abstract | Full Text

The species composition and the size structure of natural planktonic food webs may provide essential information to understand the fate of mercury and, in particular, the bioaccumulation pattern of Hg2+ in the water column of lake ecosystems. Heterotrophic and autotrophic picoplankton and phytoplankton are the most important entry points for Hg in aquatic ecosystems since they concentrate Hg2+ and MeHg from ambient water, making them available to planktonic consumers at higher trophic levels of lake food webs. In this investigation we studied the uptake of 197Hg2+ in natural plankton assemblages from four Andean lakes (Nahuel Huapi National Park, Patagonia, Argentina), comprised in the size fractions 0.2-2.7 μm (picoplankton), 0.2-20 μm (pico and nanoplankton) and 20-50 μm (microplankton) through experiments using Hg2+ labeled with 197Hg2+. The experimental results showed that the uptake of Hg2+ was highest in the smallest plankton fractions (0.2-2.7 μm and 0.2-20 μm) compared to the larger fraction comprising microplankton (20-50 um). This pattern was consistent in all lakes, reinforcing the idea that among pelagic organisms, heterotrophic and autotrophic bacteria with the contribution of nanoflagellates and dinoflagellates constitute the main entry point of Hg2+ to the pelagic food web. Moreover, a significant direct relationship was found between the Hg2+ uptake and surface index of the planktonic fractions (SIf). Thus, the smaller planktonic fractions which bore the higher SI were the major contributors to the Hg2+ passing from the abiotic to the biotic pelagic compartments of these Andean lakes.