Phytoplankton and primary production in clear-vegetated, inorganic-turbid, and algal-turbid shallow lakes from the pampa plain (Argentina)

LUZ ALLENDE; GUILLERMO TELL; HORACIO ZAGARESE; ANA TORREMORELL; GONZALO PÉREZ; JOSÉ BUSTINGORRY; ROBERTO ESCARAY; IRINA IZAGUIRRE

HYDROBIOLOGIA

SPRINGER

Año: 2009 vol. 624 p. 45 - 60

0018-8158

Shallow lakes often alternate between twopossible states: one clear with submerged macrophytes,and another one turbid, dominated byphytoplankton. A third type of shallow lakes, theinorganic turbid, result from high contents of suspendedinorganic material, and is characterized by lowphytoplankton biomass and macrophytes absence. Inour survey, the structure and photosynthetic properties(based on 14C method) of phytoplankton were relatedto environmental conditions in these three types oflakes in the Pampa Plain. The underwater light climatewas characterized. Clear-vegetated lakes were moretransparent (Kd 4.5–7.7 m-1), had high DOC concentrations([45 mg l-1), low phytoplankton Chl a (1.6–2.7 lg l-1) dominated by nanoflagellates. Phytoplanktonproductivity and photosynthetic efficiency(a * 0.03 mgC mgChla-1 h-1 W-1 m2) were relativelylow. Inorganic-turbid lakes showed highest Kdvalues (59.8–61.4 m-1), lowest phytoplankton densities(dominated by Bacillariophyta), and Chl a rangedfrom 14.6 to 18.3 lg l-1. Phytoplankton-turbid lakesshowed, in general, high Kd (4.9–58.5 m-1) dueto their high phytoplankton abundances. Theselakes exhibited the highest Chl a values (14.2–125.7lg l-1), and the highest productivities and efficiencies(maximum 0.56 mgC mgChla-1 h-1 W-1 m2). Autotrophicpicoplankton abundance, dominated by ficocianine-rich picocyanobacteria, differed among theshallow lakes independently of their type (0.086 9105–41.7 9 105 cells ml-1). This article provides acomplete characterization of phytoplankton structure(all size fractions), and primary production of the threetypes of lakes from the Pampa Plain, one of the richestareas in shallow lakes from South America.