INVESTIGADORES
UNREIN Fernando
artículos
Título:
Responses of a maritime antarctic lake to a catastrophic draining event under a climate change scenario
Autor/es:
IZAGUIRRE, I.; PIZARRO, H.; ALLENDE, L.; UNREIN, F.; RODRIGUEZ, P.; MARINONE, M. C.; TELL, G.
Revista:
POLAR BIOLOGY
Editorial:
SPRINGER
Referencias:
Año: 2012 vol. 35 p. 231 - 239
ISSN:
0722-4060
Resumen:
Under a climate change context evidenced by an increasing air temperature trend reported for the last 50 yr for Esperanza/Hope Bay (Antarctic Peninsula), we evaluated the historical changes in the limnological features and in phytoplankton structure in Lake Boeckella, the main lake of this region. We analysed data obtained in the lake during the austral summers from 1991 to 2007. At the beginning of January 2001 a sudden and remarkable water level decrease (~3 m) occurred in the lake as a consequence of an extremely high water discharge to the sea through the effluent, triggered by the progressive thawing of the permafrost in the basin of the system. After this episode, nutrients, conductivity, chlorophyll a and phytoplankton density showed strong peaks. Historical data revealed statistically significant increasing trends for dissolved reactive phosphorus, conductivity, and phytoplankton abundance. Secchi disk depth showed a significant decrease during the study period, resulting in a thinner euphotic layer. Chrysophyceae and Volvocales dominate the phytoplankton fraction > 2 μm in the lake, but from 2004 onwards small eukaryotic algae (3-5 μm) became also very abundant. Autotrophic picoplankton showed a strong peak during the summer when the water level decrease occurred. A shift in their composition was observed through the study period: in 1998 picocyanobacteria were numerically dominant, from 2002 onwards picoeukaryotes increased, and became completely dominant in 2004. This historical study provides additional evidences on the effect of the climate change on Maritime Antarctic lakes, which may accelerate their eutrophication.