Multivariate statistics for spatial and seasonal quality assessment of water in the Doce River basin, Southeastern Brazil

Macrophytes are plant organisms that live partially or totally submerged in water, being fixed and free. The Doce River is one of the main rivers in southeastern Brazil and, in 2015, it was hit by ore tailings from the Fundão dam burst in Mariana, Minas Gerais. This work aims to provide a floristic survey of macrophytes in the lower Doce River basin and to compare the species composition between lentic and lotic environments. Expeditions were carried out monthly from October 2018 to September 2019, in five stations in lotic and six in lentic environments. A total of 105 species belonging to 33 families of vascular plants were recorded, among them 14 are new occurrences for Espírito Santo state. Richest families were Poaceae (23 spp.) and Cyperaceae (22 spp.). Amphibious/emerging plants were the most representative (46 spp.). NMDS analysis revealed that the composition of the lotic and lentic environments are different.

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Biological aspects of Hypostomus affinis (Siluriformes: Loricariidae) in Brazilian coastal rivers

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x1121 ◽

2022 ◽

Vol 34 ◽

Author(s):

Tiago Magalhães da Silva Freitas ◽

Gilberto Nepomuceno Salvador

Keyword(s):

River Basin ◽

Condition Factor ◽

Southeastern Brazil ◽

Energetic Cost ◽

Breeding Period ◽

Reproductive Process ◽

Rainfall Variation ◽

Biological Aspects ◽

Doce River ◽

Paraíba Do Sul River

Abstract Aim Determine the length-weight relationship (LWR), the period of reproduction, and evaluate the variation of the condition factor (K) of Hypostomus affinis from two coastal drainages in southeastern Brazil, assessing the influence of the rainfall on these biological aspects. Methods fish were sampled quarterly between April 2008 and April 2010 in tributaries of the Doce River basin (DRB) and the Paraíba do Sul River basin (PSRB). Specimens were caught using gillnets. LWR parameters were assessed by location and sex through a t-test. We used the frequency of mature specimens (FM) to evaluate the breeding period. Both FM and K values were assessed by a sinusoidal equation. Results A total of 492 specimens was captured, of which 128 were from the Doce River basin (DRB) and 364 from the Paraíba do Sul River basin (PSRB). In both areas, specimens showed a negative allometric growth type. We collected mature specimens along the studied period in both drainages, with the highest frequency observed at the beginning of the rainy season. We found a positive correlation between the rate of matures and the local rainfall variation. The condition factor (K) was lower for specimens from DRB and did not show a cyclic trend. On the other hand, we observed a cyclic chance of the K values for the individual from the PSRB, peaking in the transitional dry-rainy period. However, it was not possible to correlate it to the rainfall variation. Conclusions LWR parameters of H. affinis were consistent with data already available in the literature. The rainfall may influence the FM but not the K values. In this case, biological characteristics such as reproduction and (or) feeding may be jointly driving a discrete variation of K values. The reduction in K values in the rainy periods suggests a remarkable energetic cost for the reproductive process. In short, our results help us to understand the life cycle of a fish species within a highly modified environment, especially by dams.

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Meteorological and hydrological drought from 1987 to 2017 in Doce River Basin, Southeastern Brazil

RBRH ◽

10.1590/2318-0331.252020190181 ◽

2020 ◽

Vol 25 ◽

Cited By ~ 2

Author(s):

Elaisa Teixeira de Jesus ◽

Jhones da Silva Amorim ◽

Rubens Junqueira ◽

Marcelo Ribeiro Viola ◽

Carlos Rogério de Mello

Keyword(s):

River Basin ◽

Standardized Precipitation Index ◽

Meteorological Drought ◽

Rain Gauge ◽

Hydrological Drought ◽

Southeastern Brazil ◽

Economic Sectors ◽

Historical Series ◽

The Standardized Precipitation Index ◽

Doce River

ABSTRACT Meteorological drought is a natural hazard characterized as below-average precipitation from expected or normal that can affect various economic sectors, and lead to period with inadequate streamflow for established uses of the water (hydrological drought). We aimed to apply the Standardized Precipitation Index (SPI) and Standardized Streamflow Index (SSI) to identify the occurrence and the intensity of droughts in Doce River Basin (DRB), Southeastern Brazil. For this purpose, 71 rain gauge stations and one streamflow station were selected with 30-year monthly historical series (1987 to 2017). The SPI and SSI were calculated for the hydrological year (October-September) and the seasons (Spring, Summer, Fall, and Winter). SPI mapping was performed by geostatistical procedures. Pearson's coefficient was calculated to analyze the influence of meteorological on hydrological drought. The main meteorological drought events, observed in the hydrological years of 1994/95, 2000/01, and a recent and consecutive period of four hydrological years (2013-2017), were mainly influenced by events in spring and summer and, to a lesser extent, in fall. It was observed the influence of the meteorological drought on the hydrological drought on an annual and seasonal scale, except winter, where low precipitation does not influence in the streamflow.

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