Hydrochemistry and trophic state change in a large reservoir in the Brazilian northeast region under intense drought conditions

Santos, J. A. C.; Marins, Rozane Valente; Aguiar, José Edvar; Challar, Guillermo; Silva, Francisco A.T.F.; Lacerda, Luiz Drude de

doi:10.4081/jlimnol.2016.1433

Cited by 17 publications

(27 citation statements)

References 24 publications

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“…limnetica/Pl. minor, were mainly associated with reduced phosphate-P supply in phase I, which could be due to the strong thermocline in this period (see Santos et al, 2017). Corroborating this condition, Pl.…”

Section: Discussionmentioning

confidence: 99%

“…The analysis of the results of spatial and temporal dynamics of the phytoplankton community in the Castanhão reservoir along the years of 2012 and 2013, when the volume of the reservoir progressively decreased from 70% to 50% (Santos et al, 2017), showed a tendency of temporal rather than spatial variation across the zones. In general, the study period could be divided in three phases based on the phytoplankton structure.…”

Section: Discussionmentioning

confidence: 99%

“…papillaterminata (MP). In this phase, the reservoir was classified as oligotrophic based on the total phosphorous and chlorophyll a concentrations (Santos et al, 2017). It is important to note that the highest phytoplankton density observed in phase I was not associated to a high phytoplankton biomass (chlorophyll a), precisely due to the dominance of these slender filamentous cyanobacteria, especially Pl.…”

Section: Discussionmentioning

confidence: 99%

“…Seasonal fluctuations in rainfall alter the water volume stored by reservoirs as well as other environmental variables, such as mixing conditions, turbidity, oxygen and nutrients contents in the water column (Chaves et al, 2013;Mosley et al, 2015;Santos et al, 2017). These changes, in turn, lead to shifts in phytoplankton attributes (Chellappa et al, 2009;Câmara et al, 2015), which reinforce the use of this community to evaluate the environmental status of these aquatic ecosystems.…”

Section: Introductionmentioning

confidence: 99%

“…For chlorophyll a analysis the samples were filtered immediately after sampling in a field lab through 47-mm-diameter AP40 glass fiber filters. More detailed field procedures and analytical methods were described previously by Santos et al (2017).…”

Section: Sampling Environmental Variables and Chlorophyll Amentioning

confidence: 99%

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Assessing temporal and spatial variability of phytoplankton composition in a large reservoir in the Brazilian northeastern region under intense drought conditions

et al. 2017

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The present study was carried out in Castanhão Reservoir, a large aquatic system in the Brazilian semi-arid region that serves multiples uses as water drinking supply and intensive fish-cage aquaculture site. In order to understand the effects of environmental conditions on the spatial and temporal variability of the phytoplankton functional groups (FG) and the main 'characterizing taxa', sub-superficial water samples were collected from March 2012 to August 2013, a period distinguished by the continuous drop in reservoir volume due to rainfall shortage. Eighteen functional groups and 102 total phytoplankton taxa were found in the Castanhão reservoir during the study. No significant differences were observed relative to spatial variation of total phytoplankton composition throughout the reservoir (PERMANOVA, P>0.05). On the other hand, according to cluster analysis results, three temporal phases have been identified (Similarity Profile, P<0.05), based on 102 phytoplankton taxa. The 'characterizing taxa' was found using the Similarity Percentage procedure (cut-off 90%), being thus defined as those taxa that contributed the most to the similarity within each temporal phase. Nineteen 'characterizing taxa' described the Castanhão reservoir, with predominance of those typical of mixing and turbidity conditions. Cyanobacteria dominated through the three temporal phases. According to the redundancy analysis, nutrient availability and water transparency were found to influence the phytoplankton temporal dynamics. The phase I (rainy season) was most represented by Planktolyngbya minor/Pl. limnetica (FG=S1), which reached best performance under strongly decreased phosphate-P concentrations and low water transparency. In phase II (dry season), Pseudanabaena sp.1 (FG=?) outcompeted other cyanobacteria probably due the increase in water transparency and decrease in ammonium-N. Finally, in phase III (rainy season) the decrease of water transparency triggered a recovery of shade-adapted cyanobacteria, but at this time mostly represented by Pseudanabaena limnetica (FG=S1). Phase III was also distinctive from the other ones by the highest Nitrate-N and phosphate-P concentrations related to thermocline disruption, which favored an increase in total phytoplankton biomass recorded by the augment of green algae density (FGs=X1, J and F). We concluded that the temporal dynamics of phytoplankton composition was associated to environmental changes in Castanhão Reservoir from 2012 to 2013, which were driven by seasonal climate variation from region (rainy/dry seasons), as well as, by the reduction in reservoir volume that resulted in the disruption of the thermocline, water mixing and an increase in inorganic P and N.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Sampling Environmental Variables and Chlorophyll Amentioning

confidence: 99%

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Assessing temporal and spatial variability of phytoplankton composition in a large reservoir in the Brazilian northeastern region under intense drought conditions

et al. 2017

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Water vulnerability to pesticide contamination in a Brazilian semiarid watershed

Francelino

Azevedo

Oliveira

et al. 2022

Integr Envir Assess & Manag

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This study aimed to prepare an inventory of the main active ingredients of pesticides and estimate the risk of pollution of groundwater and surface water resources in a Brazilian semiarid basin. The inventory was prepared using data from government agency databases. The contamination risk estimate was obtained using the GOSS index, Groundwater Ubiquity Score (GUS), Groundwater Screening Index (GSI), Leachability Index (LIX), US Environmental Protection Agency (USEPA) criteria, Leaching Index (LEACH), and Relative Leaching Potential Index (RLPI). The inventory identified 57 active ingredients commercialized under a well‐defined chemical class. Most of these (51.5%) belong to the very dangerous class, while 43.6% belong to the moderately toxic class. The GOSS model showed that 23.7% of the active ingredients have a low potential, 50.85% have a moderate potential, and 13.56% have a high potential for surface water contamination, with its transport being associated with the sediment. The GUS index indicates a low potential for groundwater contamination. However, the GSI points to a high potential for water contamination, the USEPA criteria for a possible contamination of groundwater, and, according to the LIX, most of the pollutants do so by leaching. The information provided contributes to the management of xenobiotic compounds in arid and semiarid basins, adding to the water security effort by providing tools for the assessment of potential pesticide pollution. Integr Environ Assess Manag 2023;19:804–816. © 2022 SETAC

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Phosphorus partitioning in sediments from a tropical reservoir during a strong period of drought

Santos

Oliveira

Araújo

et al. 2016

Environ Sci Pollut Res

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Monitoring phosphorus (P) concentration in water and sediments in the Castanhão reservoir, under intensive aquaculture, in Northeastern Brazil showed internal process to dominate P cycling following a reduction of reservoir volume due to an extended drought period. A strong negative correlation between soluble reactive phosphorus in surface waters (SRPs) with the reservoir volume results from diminishing dilution capacity; bottom water SRP showed no significant correlation with volume and imply SRP remobilization to surface layers. Total suspended solids (TSS) showed a significant correlation with chlorophyll-a, suggesting change primary productivity following SRP enrichment of surface waters and living cells dominating the TSS. As a result, eutrophication, as established by a trophic state index, was triggered in the reservoir probably enforced by intensive fish farming effluents, whose nutrients accumulated in bottom waters and which became available due to breaking of the thermocline. Since low rainfall periods are typical of the semiarid region and tend to be more frequent and stronger due to climate change, multiple use of reservoirs in NE Brazil should be reevaluated.

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Hydrochemistry and trophic state change in a large reservoir in the Brazilian northeast region under intense drought conditions

Abstract: The

Cited by 17 publications

References 24 publications

Assessing temporal and spatial variability of phytoplankton composition in a large reservoir in the Brazilian northeastern region under intense drought conditions

Assessing temporal and spatial variability of phytoplankton composition in a large reservoir in the Brazilian northeastern region under intense drought conditions

Water vulnerability to pesticide contamination in a Brazilian semiarid watershed

Phosphorus partitioning in sediments from a tropical reservoir during a strong period of drought

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