IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
artículos
Título:
Seasonal baseline of nutrients and stable isotopes in a saline lake of Argentina: biogeochemical processes and river runoff effects
Autor/es:
KOPPRIO, G.A.; KATTNER, G.; FREIJE, R.H.; DE PAGI, S.J.; LARA, R.J.
Revista:
ENVIRONMENTAL MONITORING AND ASSESSMENT
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2014 p. 3139 - 3148
ISSN:
0167-6369
Resumen:
The seasonal variability of
inorganic and organic nutrients and stable isotopes and their relations with
plankton and environmental conditions were monitored in Lake Chasicó. Principal
component analysis evidenced the strong influence of the river runoff on several
biogeochemical variables. Silicate concentrations were controlled by diatom
biomass and river discharge. Higher values of nitrate and soluble reactive
phosphorus (SRP) indicated agricultural uses in the river basin. Elevated pH
values (∼9)
inhibiting nitrification in the lake explained partially the dominance of
ammonium: ∼83
% of dissolved inorganic nitrogen (DIN). The low DIN/ SRP ratio inferred
nitrogen limitation, although the hypotheses of iron and CO2 limitation are
relevant in alkaline lakes. Particulate organic matter (POM) and dissolved
organic matter (DOM) were mainly of autochthonous origin. The main
allochthonous input was imported by the river as POM owning to the arid
conditions. Dissolved organic carbon was likely top-down regulated by the
bacterioplankton grazer Brachionus plicatilis. The δ13C
signature was a good indicator of primary production and its values were
influenced probably by CO2 limitation. The δ15N
did not evidence nitrogen fixation and suggested the effects of anthropogenic
activities. The preservation of a good water quality in the lake is crucial for
resource management.