INVESTIGADORES
BEAMUD Sara Guadalupe
artículos
Título:
Summer phytoplankton composition and nitrogen limitation of the deep, naturally-acidic (pH~2.2) Lake Caviahue, Patagonia, Argentina
Autor/es:
SARA G. BEAMUD, MÓNICA M. DIAZ, FERNANDO L. PEDROZO
Revista:
LIMNOLOGICA
Editorial:
Elsevier
Referencias:
Año: 2007 vol. 37 p. 37 - 48
ISSN:
0075-9511
Resumen:
During the warm seasons of 19982004, the
naturally-acidic (pH[1]2.2) Lake Caviahue was sampled for
conductivity, temperature, oxygen, light, nutrients, and phytoplankton
(density, biomass and chlorophyll a) with a view to studying the summer
phytoplankton population changes with relation to environmental factors, as
well as the significance of nitrogen limitation on the phytoplankton yield. Lake Caviahue
is characterized by its low transparency, CO2, and N concentration; significant
P values; a distinctive vertical distribution of phytoplankton biomass with
high values along the water column; and sometimes maximum meta-hypolimnion
values. Biodiversity is very low as a result of extreme environmental
conditions, Chlorophyceae being the prevailing algae group. Two types of
bioassays were carried out to assess nitrogen limitation. For the first
bioassay, a solution of ammoniumnitrogen chloride and/or wastewater (rich in ammonium
and phosphorus) was used, while one of the lakes sediments was the source of
nutrients for the second bioassay. Contrary to the case of acidic mining lakes,
N-ammonium proved to be a significant supportive capacity limiting factor as to
phytoplankton yield. The present paper provides for the first time information
on phytoplankton nitrogen limitation in a naturally-acidic lake.