Limnological patterns in northern pantanal lagoons

Bleich, Monica Elisa; Silveira, Roberto de Moraes Lima; Nogueira, Flávia

doi:10.1590/s1516-89132009000300028

Cited by 15 publications

(9 citation statements)

References 20 publications

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“…Under anaerobic conditions, CI is expected to have low values as a consequence of the decrease of oxygen and the concomitant accumulation of reduced solutes (i.e. NH 4 ) [54], [55].…”

Section: Methodsmentioning

confidence: 99%

Stream Hydrological Fragmentation Drives Bacterioplankton Community Composition

et al. 2013

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In Mediterranean intermittent streams, the hydrological fragmentation in summer and the successive water flow re-convergence in autumn allow exploring how local processes shape the microbial community within the same habitat. The objectives of this study were to determine how bacterial community composition responded to hydrological fragmentation in summer, and to evaluate whether the seasonal shifts in community composition predominate over the effects of episodic habitat fragmentation. The bacterial community was assessed along the intermittent stream Fuirosos (Spain), at different levels of phylogenetic resolution by in situ hybridization, fingerprinting, and 16S rRNA gene sequencing. The hydrological fragmentation of the stream network strongly altered the biogeochemical conditions with the depletion of oxidized solutes and caused changes in dissolved organic carbon characteristics. In the isolated ponds, beta-Proteobacteria and Actinobacteria increased their abundance with a gradual reduction of the alpha-diversity as pond isolation time increased. Moreover, fingerprinting analysis clearly showed a shift in community composition between summer and autumn. In the context of a seasonal shift, the temporary stream fragmentation simultaneously reduced the microbial dispersion and affected local environmental conditions (shift in redox regime and quality of the dissolved organic matter) tightly shaping the bacterioplankton community composition.

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“…Under anaerobic conditions, CI is expected to have low values as a consequence of the decrease of oxygen and the concomitant accumulation of reduced solutes (i.e. NH 4 ) [54], [55].…”

Section: Methodsmentioning

confidence: 99%

Stream Hydrological Fragmentation Drives Bacterioplankton Community Composition

et al. 2013

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“…Under low dissolved oxygen concentration, it will be expected an increase of solutes in reduced form (i.e., NH 4 ) (Bleich et al 2009;Stanhope et al 2009). Thus, the CI index will present low values, while in aerobic conditions the CI will present high values.…”

Section: Statistical Analysesmentioning

confidence: 99%

“…As a consequence of the absence of advection, the chemical characteristics of isolated waters change radically from solutes in oxidized state (i.e., N-NO 3 ) to reduced states (i.e., N-NH 4 ), with an impact on microbial processes regulating elemental cycles at local scale. For instance, it is expected a decrease in oxygen, nitrate and sulphate concentrations, and an increase in ammonium (Bleich et al 2009;Stanhope et al 2009). Focusing on DOM, an increase of dissolved organic carbon (DOC) and nitrogen (DON) bulk concentration is expected in water pools as result of continuous leaching of particulate organic matter that enters constantly from the surrounding riparian environment (Acuña et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Dissolved organic matter composition in a fragmented Mediterranean fluvial system under severe drought conditions

et al. 2010

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In Mediterranean regions, drought is one of the main factors shaping fluvial ecosystems. Droughts cause a shift from lotic to lentic conditions, triggering a gradual fragmentation of the longitudinal hydrological continuum, and a severe alteration of water chemical properties. However, within a biogeochemical perspective, little is known about how and to which extend droughts modify the chemical properties of dissolved organic matter (DOM). In this study, the variability of DOM properties along a fragmented fluvial system is explored, during a summer severe drought, by means of (a) the ratio between dissolved organic carbon and nitrogen concentrations (DOC:DON); (b) DOC bioavailability (BDOC) and (c) DOM optical properties (SUVA index, fluorescence index, and excitationemission fluorescence matrices). DOM and water measurements were collected from isolated water parcels that became disconnected from the fluvial continuum at different times, and were compared with data obtained in the following autumn, when the fluvial continuum was re-established. Analysis of DOM chemical properties evidenced that these properties during drought clearly differed from those observed in autumn, but changes did not follow an arbitrary pattern. Thus, the sampling sites with lotic water bodies showed DOM properties similar to those observed in autumn reflecting the dominance of terrestrial inputs. But, once hydrological fragmentation occurred, there was a gradual increase in the contribution of autochthonous DOM as the time elapsed since the pools were established, and the geochemical conditions shifted from oxidized to reduced conditions. In consequence, the fragmentation of fluvial continuum generates a set of distinct biochemical hot spots (i.e., each water parcel), revealing that extreme drought greatly amplifies the qualitative heterogeneity of organic matter in a fluvial system.

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“…interfere in the results. The alterations occurring in the abiotic variables of the lake water during the experiment were observed both in the mesocosms and in the control, and showed values considered natural for this time of year (Bleich et al, 2009). Fish were excluded by the 100 and 200 µm mesh.…”

Section: Composition and Structure Of The Zooplanktonmentioning

confidence: 99%

Top-down control in a tropical shallow lake of Northern Pantanal, Brazil

Silveira¹,

Paiva²,

Camargo³

2010

Acta

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Aim: To test the effect of fish exclusion over zooplankton and phytoplankton in a shallow lake in the floodplains of the Cuiabá River in Brazil's Pantanal; Methods: Fishes and two classes of zooplankton sizes were excluded using mesocosms (100 µm and 200 µm mesh openings). The experiment lasted nine days with sampling at the beginning, six and nine days after the start of the experiment. Zooplankton and phytoplankton densities were compared among exclusion treatments and the open water which was considered as control areas by a Repeated Measures Analysis of Variance; Results: The zooplankton composition and densities differed considerably between the exclusion treatments and the control areas, with a predominance of Cladocera and Copepoda in the exclusion treatments and a predominance of Rotifera in the control areas. During the experiment, the composition of the phytoplankton assemblage showed no difference between the exclusion and the control. However, there was a marked reduction in the density of the Cyanophyta and Chlorophyta algae among the exclusion treatments; Conclusions: The increase in density and the variation in the zooplankton composition suggest that these organisms are controlled by the fish and demonstrate that the zooplankton may exert control over the density of phytoplankton.

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Limnological patterns in northern pantanal lagoons

Abstract: ABSTRACT

Cited by 15 publications

References 20 publications

Stream Hydrological Fragmentation Drives Bacterioplankton Community Composition

Stream Hydrological Fragmentation Drives Bacterioplankton Community Composition

Dissolved organic matter composition in a fragmented Mediterranean fluvial system under severe drought conditions

Top-down control in a tropical shallow lake of Northern Pantanal, Brazil

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