Initial report on methane and carbon dioxide emission dynamics from sub-Antarctic freshwater ecosystems: A seasonal study of a lake and a reservoir.
The sub-Antarctic Magellanic ecoregion is a part of the world where ecosystems have been understudied and where the CH4cycling and emissions in lakes has not ever been reported. To fill that knowledge gap, a lake and a reservoir located at 53°S were selected and studied during three campaigns equally distributed over one year. Among the parameters measured were CH4and CO2emissions, as well their dissolved concentrations in the water column, which were determined with high spatial resolution. No ebullition was observed and the CH4flux ranged from 0.0094 to 4.47mmolm-2d-1while the CO2flux ranged from -22.95 to 35.68mmolm-2d-1. Dissolved CH4concentrations varied over more than four orders of magnitude (0.025-128.75μmolL-1), and the dissolved carbon dioxide ranged from below the detection limit of our method (i.e., 0.15μmolL-1) to 379.09μmolL-1. The high spatial resolution of the methods used enabled the construction of bathymetric maps, surface contour maps of CH4and CO2fluxes, and transect contour maps of dissolved oxygen, temperature, and dissolved greenhouse gases. Overall, both lakes were net greenhouse gas producers and were not significantly different from temperate lakes located at a similar northern latitudes (53°N), except that ebullition was never observed in the studied sub-Antarctic lakes.
Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Departamento de Biotecnología y Bioingeniería, Av. IPN 2508, 07360 México, DF, Mexico.
Oscar
O
Gerardo-Nieto
Universidad de Magallanes, Departamento de Ciencias y Recursos Naturales, POB 113-D, Punta Arenas, Chile.
María Soledad
MS
Astorga-España
Universidad de Magallanes, Departamento de Ciencias y Recursos Naturales, POB 113-D, Punta Arenas, Chile; Instituto de Ecología y Biodiversidad, Casilla 653, Santiago, Chile.
Andrés
A
Mansilla
Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN), Departamento de Biotecnología y Bioingeniería, Av. IPN 2508, 07360 México, DF, Mexico; Universidad de Magallanes, Departamento de Ciencias y Recursos Naturales, POB 113-D, Punta Arenas, Chile. Electronic address: thalasso@cinvestav.mx.
Frederic
F
Thalasso
CH(4); Carbon dioxide; Contour maps; Dissolved gas; Oxygen