scholarly journals How the fluctuations of water levels affect populations of invasive bivalve Corbicula fluminea (Müller, 1774) in a Neotropical reservoir?

2015 ◽  
Vol 75 (1) ◽  
pp. 135-143 ◽  
Author(s):  
LRP. Paschoal ◽  
DP. Andrade ◽  
G. Darrigran

Corbicula fluminea is an invasive bivalve responsible for several environmental and financial problems around the globe. Despite the invasive potential of this species, it suffers certain restrictions in lentic environments due to natural phenomena that significantly affect its population structure (e.g. water column fluctuation and sunlight exposure). The present study addresses how temporal decline of the water level in a Neotropical reservoir and exposure to sunlight affect the population structure of C. fluminea. Samplings were carried out twice in the reservoir of Furnas Hydroelectric Power Station (HPS) (Minas Gerais, Brazil), in 2011 and 2012. Population density, spatial distribution and mean shell length of C. fluminea were estimated for each year after sampling in 51 quadrats (0.0625m2) placed on three transects at different distances along the reservoir margins (0, 10 and 20 m from a fixed-point). We observed a predominance of C. fluminea in both years, with a simultaneous gradual decrease in density and richness of native species in the sampling area. Significant differences in density of C. fluminea were registered at different distances from the margin, and are related to the temporal variability of physical conditions of the sediment and water in these environments. We also registered a trend toward an increase in the density and aggregation of C. fluminea as we moved away from the margin, due to the greater stability of these areas (>10 m). The mean shell length of C. fluminea showed significant difference between the distinct distances from the margin and during the years, as well as the interaction of these factors (Distances vs.Years). These results were associated with the reproductive and invasive capacity of this species. This study reveals that these temporal events (especially water column fluctuation) may cause alterations in density, spatial distribution and mean shell length of C. fluminea and the composition of the native malacofauna in Neotropical lentic environments.

Author(s):  
Himangshu Barman ◽  
Soujita Pramanik ◽  
Gargi Nandy ◽  
Sampa Banerjee ◽  
Gautam Aditya

The spatial distribution and morphological features of the land snail Succinea baconi (Pfeiffer, 1854) (Gastropoda: Succineidae) from India were evaluated. The survey performed in gardens and bushes in Coochbehar, West Bengal, India, has made it possible to assess the abundance of the snail S. baconi on the randomly selected lemon plants (n = 18). Logistic regressions were employed to judge differences in vertical distribution, resource association and size class variation in the snails under study. Variation in shell morphology was assessed by performing the regression analysis of the sampled shells of live snails (n = 258) and vacant shells of the deceased individuals (n = 100). An overall significant difference (p < 0.05) in the vertical distribution of snails in lemon plants was observed. As to their association with resources available, snails were found to be more abundant in detritus than on living parts of the plants. The performed logistic regression revealed that the relative abundance of different S. baconi size classes was significantly different (p < 0.001). Significant correlations (p < 0.001) were found among different body size variables, with the shell length (x)-body weight (y) relationship being: y = 0.232x2.524 (for live snails) and the shell length (x)-shell weight (y) relationship being: y = 0.358x2.537 (for shells of dead snails). Various parameters of the snail shell shape could be represented through regression equations. Although reproduction and growth strategies of snails need to be explored further, the presented observations improve our understanding of the ecology of S. baconi, which may prove useful for future conservation efforts.


Author(s):  

This article presents the results of the assessment of production and destruction processes in the ecosystem of the Kharanorsk reservoir-cooler, used as a cooling pond of the Kharanorsk hydroelectric power station. The content of dissolved oxygen in the water of the reservoir is ubject to seasonal dynamics corresponding to biochemical processes occurring in the reservoir. In spring and autumn, the concentration of dissolved oxygen is in the range from 12.6 to 14.2 mg / L. We attribute the decrease in oxygen content in the summer month to 9.6 mg / L with an increase in air temperature and with the thermal effect of thermal power plants, which in total lead to an intensification of the processes of biochemical decomposition of organic and oxidation of mineral substances. High production capabilities of the ecosystem in both the central and littoral zones were found in July in the surface horizons of the water column (3.53 mgO2 / L – littoral; 3.92 mgO2 / L – center). The formation of organic matter in the direction “surface horizon - bottom layers” of the water column in the central zone decreases due to a decrease in the transparency of the water column. The cessation of the production of organic matter by phytoplankton in the bottom layers of the littoral zone we associate with the competitive relationship of bottom organisms in the use of nutrients. It has been established that the rate of daily production increases from April to July and begins to fall in October, but remains high relative to spring indicators in both the central and littoral zones of the reservoir. The studies are necessary for subsequent environmental monitoring studies, as well as for making managerial decisions to maintain the sustainability of the reservoir ecosystem.


Author(s):  
Anna Klikunova ◽  
Tatyana Dyakonova ◽  
Ekaterina Agafonnikova ◽  
Ilya Makoveev ◽  
Mariya Kornaukhova ◽  
...  

The problem of flooding of territories with flood waters for settlements of the Volgograd region is considered. A numerical model of flood water dynamics is constructed, taking into account the topography of the terrain. The simulation is based on two-dimensional shallow water equations. For computational experiments, a parallel implementation of the numerical scheme CSPH-TVD for NVIDIA graphics accelerators with CUDA technology is used. The digital model of the river-bed and floodplain relief is based on spatial data SRTM3 and SRTMGL, topographic maps of the area, longitudinal profiles of rivers. The water flow rates for the Buzuluk and Perevozinka rivers are determined and a hydrograph of the Volga hydroelectric power station is constructed for the given probabilities of exceeding the water level. Flood maps were obtained for the following localities: Novoannisky, Berezovka 1st, kh. Vyazovka. The maximum values of the depths for 1 %, 3 %, 5 %, 10 %, 25 % and 50 % of water security are presented. An analysis of the flood situation was carried out and appropriate engineering and protective measures for settlements were proposed. At maximum flood water levels, residential buildings of kh. Berezovka 1-I are not subject to flooding. In order to minimize the negative impact for the city of Novoanninsky, it is proposed to carry out timely clearing of the river-bed of the Perevozinka river from congestion. To protect from flooding ch. Vyazovka it is recommended to use diversion dyke.


2018 ◽  
Vol 17 ◽  
pp. 46-52 ◽  
Author(s):  
Lyubov A. Zhivoglyadova ◽  
Nikolai K. Revkov

The bivalve Corbicula fluminea (O. F. Müller, 1774) were considered as new alien species for the first time registered in the River Don. One alive specimen was found in the Teplyj Kanal (Warm Channel) near the Novocherkassk hydroelectric power station, and two specimens were observed in the Don main riverbed near the mouth of the Teplyj Kanal. We have considered extended expansion of this species after its first finding in fresh waters of France, Portugal and Germany throughout the European continent towards the area where it was found in the Lower Don.


2018 ◽  
Vol 245 ◽  
pp. 15002 ◽  
Author(s):  
Roman Davydov ◽  
Valery Antonov ◽  
Dmitry Molodtsov ◽  
Alexey Cheremisin ◽  
Vadim Korablev

The rapid spread of storm floods over large areas requires flood management throughout the river basin by the creation an innovative system of flood control facilities of various functional purposes distributed in the area. The central part of the system is the hydro system with hydro power plant. In addition, the flood control facilities on the side tributaries with self-regulating reservoir are included in the system. To assess the effect of controlling extreme water discharges by flood control facilities, it is necessary to develop special mathematical models reflecting the specifics of their operation. Unified mathematical models of the operation modes of a hydro complex with hydroelectric power station and flood control facility are created. They are implemented in a computer program that provides the ability to determine the main parameters and operating characteristics of hydro systems when performing multivariate calculations in a wide range of initial data. This makes possible specifying the parameters and operation modes of each hydro system with the current economic and environmental requirements, to assess the energy-economic and environmental consequences in the operation of the system of flood control facilities distributed in the area. The article analyses the results of the extreme water discharge’s regulation by the hydro system on the main river and flood control facilities on the side tributaries, considering environmental requirements.


Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 449
Author(s):  
Yashira Marie Sánchez Colón ◽  
Fred Charles Schaffner

Laguna Cartagena is a coastal, eutrophic, shallow lake and freshwater wetland in southwestern Puerto Rico, managed by the US Fish and Wildlife Service. This ecosystem has been impacted by phosphorus loading from adjacent agricultural areas since the 1950s, causing eutrophication and deteriorating wildlife habitats. Herein, we describe phosphorus input and export during September 2010–September 2011 (Phase One) and October 2013–November 2014 (Phase Two). These two phases bracket a period of intensified management interventions including excavation and removal of sediment and vegetation, draining, and burning during the summers of 2012 and 2013. Results indicate that Laguna Cartagena retains a phosphorus (sink) in its sediments, and exhibits nutrient-releasing events (source, mainly total phosphorus) to the lagoon water column, which are associated with rainfall and rising water levels. External factors including water level fluctuations and rainfall influenced phosphorus export during Phase One, but after management interventions (Phase Two), internal processes influenced sink/source dynamics, releasing elevated phosphorus concentrations to the water column. When exposed sediments were re-flooded, phosphorus concentrations to the water column increased, releasing elevated P concentrations downstream to an estuarine wetlands area and the Caribbean Sea. Herein we offer management recommendations to optimize wildlife habitat without elevating phosphorus concentrations.


1974 ◽  
Vol 8 (10) ◽  
pp. 914-916
Author(s):  
I. S. Ronzhin ◽  
A. D. Osipov ◽  
V. Kh. Gol'tsman ◽  
A. B. Yumatov

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