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

Abstract

Shallow lakes often alternate between two possible states: one clear with submerged macrophytes, and another one turbid, dominated by phytoplankton. A third type of shallow lakes, the inorganic turbid, result from high contents of suspended inorganic material, and is characterized by low phytoplankton biomass and macrophytes absence. In our survey, the structure and photosynthetic properties (based on 14 C method) of phytoplankton were related to environmental conditions in these three types of lakes in the Pampa Plain. The underwater light climate was characterized. Clear-vegetated lakes were more transparent (K d 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. Phytoplankton productivity and photosynthetic efficiency (a * 0.03 mgC mgChla -1 h -1 W -1 m 2 ) were relatively low. Inorganic-turbid lakes showed highest K d values (59.8-61.4 m -1 ), lowest phytoplankton densities (dominated by Bacillariophyta), and Chl a ranged from 14.6 to 18.3 lg l -1 . Phytoplankton-turbid lakes showed, in general, high K d (4.9-58.5 m -1 ) due to their high phytoplankton abundances. These lakes exhibited the highest Chl a values (14.2-125.7 lg l -1 ), and the highest productivities and efficiencies (maximum 0.56 mgC mgChla -1 h -1 W -1 m 2 ). Autotrophic picoplankton abundance, dominated by ficocianine-rich picocyanobacteria, differed among the shallow lakes independently of their type (0.086 9 10 5 -41.7 9 10 5 cells ml -1 ). This article provides a complete characterization of phytoplankton structure (all size fractions), and primary production of the three types of lakes from the Pampa Plain, one of the richest areas in shallow lakes from South America.

Influence of re-flooding on phytoplankton assemblages in a temperate wetland following prolonged drought

“…We also found high relative proportions of euglenoids; it is recognized that the drying phase of temporary water bodies is characterized by a very diverse assemblage mainly formed by euglenoids (W1 and W2 FG) often accompanied by dinoflagellates (L o FG) because they generally persist to the point of complete desiccation of the pond (Naselli-Flores and Barone, 2012). The dominance of benthic Bacillariophyceae (C and T B FG) during the initial period was favored by the absence of macrophytes as it is recognized that heavy diatoms rely on turbulence to counteract sedimentation (Padisák et al, 2003;Allende et al, 2009;Stević et al, 2013).…”

“…The dominance of Cryptophyceae on different sampling dates, can be explained by the fact that Cryptomonas marsonii and C. cf. obovata (Y FG), are typical mixotrophic flagellated organisms that can withstand occasional nitrogen and light limitation, as they can ingest bacteria (Tranvik et al, 1989;Jones, 2000;Urabe et al, 2000;Sinistro et al, 2007;Unrein et al, 2007;Allende et al, 2009). This fact, and the capacity to migrate vertically in order to reach optimum light condition, allowed them to remain in the water column during the whole phytoplankton succession, and to reach a greater contribution when macrophyte cover was more profuse and/or DIN concentration was low in the late re-flooding period.…”

Zooplankton richness, abundance and biomass of two hypertrophic shallow lakes with different salinity in central Argentina

“…According to the model of alternative states of shallow lakes, they are organic turbid environments (Torremorell et al 2007, Allende et al 2009) and their primary production is dominated by phytoplankton due to the absence of macrophytes.…”

Influence of underwater light climate on periphyton and phytoplankton communities in shallow lakes from the Pampa plain (Argentina) with contrasting steady states

“…In addition, a third type was observed in this geographic region: inorganic-turbid shallow lakes with high turbidity due to suspended inorganic material (Quirós et al, 2002;Allende et al, 2009). Since the underwater light availability varies greatly amongst the different types of shallow lakes of the Pampa region and even amongst turbid lakes with different kinds of particulate matter (Pérez et al, 2010), a great variability of optical scenarios is present in the same area.…”

“…There are several studies about phytoplankton composition in relation to the optical characteristics and physicochemical properties of the shallow lakes from the Pampa plain Vinocur 1994a, 1994b;Allende et al, 2009;Pérez et al, 2010;Izaguirre et al, 2012). However, the information about the periphyton community of this region is still scarce (e.g., Cano et al, 2008;Casco et al, 2009).…”