The body mass index is influenced by the environment in populations of Artibeus planirostris (Chiroptera: Phyllostomidae)?

Bats are the second most diverse taxa of mammals in the world, after rodents. Some studies have evaluated if there is a relationship between the environment and the morphology of bats, because environmental conditions can have an important influence on the phenotype of the species. The aim of the present study is to evaluate the relationship between a morphological variable (body mass index - BMI) of populations of the species Artibeus planirostris and the environment, considering the climatic variation in two hydrographic basins of the center of the Brazilian Amazon. The hypothesis is that the BMI responds to the environmental variables of each site. This will be higher during the rainy season and in the high water period, responding to a high availability of resources, according to studies carried out in the same region. 400 bats were captured, of which 180 were males and 220 were females. Although the index seemed to show differences considering the sex of the individuals, both in the Madeiras river basin (ANOVA: gl = 1, F = 6.90, P = .00) and in the Purus river (ANOVA: gl = 1, F = 3.95, P = .01), there was no significant difference between the BMI and the different environments, considering the climate season. It is concluded that, in this study, no evidence was found to support the hypothesis about the influence of the environment on BMI in populations of the bat species Artibeus planirostris in the center of the Brazilian Amazon.

Toward the understanding of saline water intrusion and nutrient flushing in Lake Nokoué

To understand the salinity dynamic at the outlet of Lake Nokoué and to simulate the nutrient flushing from this lake into the Atlantic Ocean, a 2D hydrodynamic model was designed with Mike 21. The choice of the Mike 21 was motivated by the long practice that decision-makers in Benin have with this software. The Hydrodynamics (HD) module simulated water level variations and flows in response, while the ECO-Lab module has been used for water quality modelling. The data used covered the hydrological period of 2013. The results from the HD simulation indicated that for a flow of 725 m3/s at Bonou on the Ouémé River, a tributary of Lake Nokoué. 70% of the land in the delta of Ouémé, between the Ouémé River and the So River (also a tributary of Lake Nokoué), are flooded against 90% for a river flow of 1100 m3/s. The water level in the delta showed a water increase of 0.6 m, in seven days, for a water flow of 725 m3/s at Bonou and a water increase of 1.3 m, in seven days, for a water flow of 1100 m3/s at Bonou. Water quality simulations indicated that the seawater intrusion from the Atlantic Ocean into Lake Nokoué occurred from the bottom to the surface towards the surface of the lake. During flooding, despite the large inflow of fresh water, more than 60% of the water at the bottom of the lake had concentrations greater than 8. Simulation of the dispersion of nutrient point source pollution indicated that there was an accumulation of pollution at the bottom of the lake during low water periods. This accumulation increases in amplitude as one moves away from the Atlantic Ocean towards the north of the lake. In this period tidal flushing evacuated about 20% of the pollution ejected. In the high water period, about 70% of the pollution ejected in the lake was automatically flushed out in the lake the Atlantic Ocean.

South-West Benin Coastal Lagoon: Waters and sediments’ toxicity and contents in heavy metals during high water period (Togbin to the Mono Mouth)

The uncontrollable population growth is reaching Benin's rivers, especially the coastal lagoon, raising then the thorny problem of pollution, which is considerably accentuated by the malevolent behavior of the populations. The aim of this paper is to characterize the degree of contamination of the water and sediments of the lagoon in heavy metals (Cd, Cr, Zn, Cu, Pb and Fe) through the dosage with the molecular absorption spectrophotometer type DR 3900. At the same time, a cytotoxicity test with Allium cepa will be carried out in order to evaluate the toxic potential of the pollutants responsible for the degradation of the lagoon. The Cd, Cu and Zn contents in the water and sediments far exceed the accepted standards at almost all the stations. The Pollution Index (PI) and geo-accumulation index (Igeo) indicate the existence of polymetallic pollution in the sediments, which is extremely strong and dominated in order to decrease abundance by: Cd>Zn>Cu>Pb. The results of the cytotoxicity test highlight acute toxicity on 82% of the stations surveyed. The poor states of the coastal lagoon indexed by this study, impose the application of urgent measures of participative management, preservation and sanitation of the coastal zone

Effect of Rotational Speed on Performance of Mixed Flow Pump as Turbine

In order to research the flow characteristics of mixed flow pump as turbine (MF-PAT) with different rotation speeds, a hydraulic model of mixed flow pump was established based on a pumped storage power station. The k-ε turbulent model was used to simulate internal flow fields with three rotation speeds by SMPLEC algorithms. Subsequently, theoretical calculations and experiments were carried out to verify the precision of numerical simulation. The results showed that the rotation speed of MF-PAT has a significant impact on its performance. Both numerical calculations and experimental test presented that all efficiency curves consist of ascending and descending stages, while the shaft power and head increase nonlinearly from 1000 to 2000 r/min. When the MF-PAT deviates from the rated environment, increase in speed is positive to the energy recovery efficiency in the high water period and negative in the dry season. This work could provide a reference for further study of MF-PAT.

Intra-annual surface runoff distribution of The Chatkal River in different watery years

In planning water reservoirs, it’s significant to understand surface runoff behaviors, especially in medium and small rivers. The article examines water availability results during different watery years of The Chatkal River, which is the biggest left tributary of The Chirchik River. The computation of intra-annual runoff distribution for three different years of watery and for two distinguished periods of watery was carried out. It is derived that independently from the watery of year, 80% of runoff originates in high water period and 20% in the low water period.

THE «IDEAL» WAY: WAS IT POSSIBLE TRANSCONTINENTAL WATER ROUT ALONG THE RIVES OF EASTERN EUROPE?

The article shows the fallacy of traditional ideas about the existence of a water transit route from the Baltic to the Volga and the Dnieper. Due to the low water content of the rivers of Eastern Europe during the water minimum of the first Millennium ad and the presence of rapids on the Volkhov, Msta and Lovat, these rivers were unsuitable for navigation, not only for keel Scandinavian, but also for any cargo ships. The water road from Ilmen to the Volga, as well as the Dnieper (the way «from the Varangians to the Greeks») never existed. The hydrographic characteristics of Msta and Lovat exclude the possibility of platoon movement of rowing vessels along these rivers. Shipping conditions along the Western Dvina and the Dnieper were extremely difficult. The belief of historians in the river routes of Eastern Europe in the era of the Vikings VIII –XI century based on the undue transfer of social and geographical conditions of navigation in the high water period and the era of the centralized state of the II Millennium ad in the pre-state period in the era of water minimum of I Millennium ad.

Spatial and Temporal Variations of Eutrophication in Poyang Lake

<p>Lake eutrophication is a key point in water environmental problems in the world. Spatiotemporal variations of nutrients and chlorophyll-a and eutrophication index in Poyang Lake, the largest freshwater lake in China, are analyzed in this paper basing on field observation data at 17 sampling points from 2011 to 2016. The results show that nutrient concentrations have obvious seasonality characteristics and present bigger values in the low water period than the high water period. The peak value of chlorophyll-a concentration appears in July and October respectively. As a whole, the eutrophication index in the low water period is higher than the high water period, and the maximum value is found in October which mainly due to the high chlorophyll-a concentration. Poyang Lake is at light eutrophication level from 2011 to 2012, and mesotrophic from 2013 to 2016. From the perspective of space, nutrient concentrations in the southern part of the lake is higher than the northern part in general, and chlorophyll-a and eutrophication index show the similar law. This paper makes a quantitative analysis for spatial and temporal variations of eutrophication which benefit the water management especially water pollution control in Poyang Lake</p>

The Change of the Water Regime of the Volga River in the Area of the Protected Island Bakhilovsky

The ecological state of the protected Islands Seredysh and Shalyga (now Bakhilovsky island) depends on the water content and flow of the Volga River. We have analyzed the long-term changes in the water flow of the Volga River for the period 1958-2017 in the alignment Zhiguli dam, located 12 km upstream from the island. According to the average annual water consumption, there are three periods that differ from each other in water content: low-water period (1958–1976), high-water period (1977–1997) and the period of average water content (1998–2017), with extremely low-water (1967, 1973, 1975, 1976, 1977, 1996) and extremely high-water (1966, 1979, 1981, 1990, 1991, 1994) years. In highwater years, during the passage of the spring flood, the island is almost completely flooded, and in low-water years, during the summer low water, the area of the island increases and changes its configuration.

Macrophytes in the littoral of Lake Arakhley in different states of water regime

The study of aquatic vegetation in the littoral of the dimictic water bodies of taiga is of particular interest in case of long-term observations carried out under conditions of climate fluctuations. During the low-water period, drying of the littoral with a decrease in the water level leads to the changes in phytomass of macrophytes, as well as in the composition of species and their distribution by depth. The area of littoral covered with ice in winter is also large in the low-water period; it affects the growth of perennial plants. When the water level decreases, the sand beach replaces the sand and pebble beach; it leads to the disappearance of epilithon and the predominance of rooting plants. The features of vegetation were determined for each period of water content. The low-water period is characterised mostly by grass-type vegetation; the high-water period is characterised by vegetation of mixed type.