Macrobenthic Faunal Abundance, Distribution and Diversity in the Bakkhali River, East Coast of Bangladesh

The study aimed to assess the macrobenthos abundance and distribution from the Bakkhali River, East Coast of Bangladesh. Macrobenthic and water samples were collected from the upper, middle and lower part of the river during post-monsoon. Several indices were used to find macrobenthos abundance and distribution and their correlation with water parameters were also assessed. Present study identified a total of 628 macrobenthos individuals representing 10 major taxa at three stations where 9 taxa were reported in both upper and middle parts whereas only 7 taxa were observed at lower stream of the river. The highest abundance of macrobenthos (301.04 indivs/m2) was recorded at the lower stream and the lowest abundance (166.3 indivs/m2) was found at the upper part of the river. Macrobenthos distribution showed that the number of Oligochaetes was higher (220 indivs) followed by Nemertinas (169 indivs) and Polychaetes (145 indivs). Study findings reveal that macrobenthos abundance and distribution were comparatively higher at the lower stream than the upper and middle part because of higher level of pollution and sendimentation rate that might influence the macrobenthos abundance and diversity in the upper and middle part. The study also found macrobenthos abundance was proportionally increased with increasing salinity and pH. However, macrobenthos abundance was decreased with increasing temperature. Simpson index (D) was the highest (0.32) at middle and lower part and the lowest (0.23) was in the upper part. Shannon-wiener index (H) was also higher (1.68) at the upper part. Both the indices showed higher diversity at the upper part because of having maximum taxa in the station. Based on the H value, this study reported that Bakkhali River was moderately polluted since H value was in the range of 1.44 to 1.68. These might be because of anthropogenic sources of pollution in the vicinity of the river. This study suggests to take proper management strategies to control aquatic pollution and conserve aquatic biodiversity. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 10(1), 2021, P 47-55

Mathematical model and algorithmic process of solving the problem of the intra-day regulation of discharge of water through the Nizhny Novgorod low-pressure hydroelectric complex

Introduction of measures for intra-day of regulating runoff incoming water flow rates from the Nizhny Novgorod HPP and their discharge through the spillway of the Nizhny Novgorod low-pressure hydroelectric complex requires a specific algorithm for dispatcher actions of the created hydraulic system. At the same time, there are serious difficulties in predicting the water regime over time. As previous studies have shown there is a large unevenness and irregularity of water discharges not only during the same day, but also in the same periods of each day, as well as weeks, months, and years. Тhis article analyzes the boundary conditions when introducing measures of regulating runoff, a mathematical model and an algorithm for solving the problem of intraday regulation are developed, describing the sequence of actions for solving the problem of "smoothing" the flow rates supplied to the lower stream of the Nizhny Novgorod low-pressure hydroelectric complex. The implementation of the proposed measures is carried out according to a three-stage (or two-stage) schedule for regulating the flow rate and water level. The proposed measures will improve the hydraulic and hydrological conditions of the downstream reach of the Nizhny Novgorod low-pressure hydroelectric complex by which the necessary depths for navigation will be reached. Conditions have also been created to mitigate erosion processes.

Effect of precipitation and stream discharge on the source composition of stream water

<p>The exchange of water between streams and groundwater plays an important role for hydrologic and biogeochemical processes. Along a stream the composition of stream water is modified by sequential losses of stream water with the current in-stream chemical signature to the subsurface and gains of water with another signature from the subsurface. This process has been termed hydrologic turnover. To date, most studies on hydrologic turnover have been focused on small stream networks. Moreover, the influence of hydrologic conditions on hydrologic turnover has not been systematically investigated. Taking the lower Selke River in central Germany as an example, we evaluated the evolution of stream-groundwater exchange and the source composition of stream water under different precipitation and stream discharge conditions, based on a coupled stream-groundwater model built in MODFLOW using the Streamflow-routing (SFR1) package. The results show that the stream reaches could be classified into three types: permanently gaining reaches, permanently losing reaches, and transitional reaches. Transitional reaches range from losing condition at higher stream discharge or lower precipitation to gaining condition at lower stream discharge or higher precipitation. In the lower Selke River with a length of 30 km, transitional reaches account for nearly 30% of the total river length in the studied period from 2011 to 2018. Regardless of dry or wet hydrologic condition, nearly 80% of the total groundwater contribution to stream discharge at the catchment outlet were generated over 20% of the total river length. This indicates diffuse groundwater pollution such as from agricultural nitrate may enter the stream network predominantly at a few distinct reaches. Our analysis can help to prioritize areas in a catchment where reduction of diffuse groundwater pollution would have the highest impact on improving stream water quality.</p>

Archaic Dialect of Chaffinch, Fringilla coelebs (Passeriformes, Fringillidae), Song in the Lower-Dnipro Area (South Ukraine) and Its Territorial Relations

Archaic song dialect of Chaffinch (Fringilla coelebs Linnaeus, 1758) is located in the Lower-Dnipro Area. To describe it, we recorded 11673 songs of 2008 males from 43 localities in Southern Ukraine during 2004–2015. This dialect has compound spatial structure and connects with other dialects forming a well developed contact area with them. Its core was located in old forests of the lower stream of the Dnipro River. It has spread from them to the new forests in their outskirts. The complex is separated at dialect level in the cluster analysis. It includes considerable number of original song types. Their elements and structure demonstrate archaic features similar to those of other southern complexes but more modern than the old Carpathian and Danube dialects. It occupies the intermediate position between them and modern dialects of the Forest and Wood-and-Steppe Ukraine by the structure of song and is similar to the dialect of Crimean Chaffinch and the song complex of South-Eastern Ukraine.

Jeszcze o zbrodni rogozińskiej i granicy między Polską a Brandenburgią na Noteci w XIII–XIV wieku

Janusz Bieniak’s study Zarębowie i Nałęcze a królobójstwo w Rogoźnie (The Zaręba and Nalęcz Families and the Regicide in Rogoźno – 2018), alongside important discoveries and interesting proposals of a prosopographic and genealogical nature, has as its main aim to discredit information in the sources concerning the participation (possibly even direct participation) of those families in the crime committed in 1296 in Rogoźno. The crime occurred through the agency of the Margraves of Brandenburg, of the older (Johannine) line of the House of Ascania/ Anhalt. This article takes issue with several aspects of Bieniak’s argument. Bieniak questions my earlier view of the probable recognition of the Nałęcz family of the suzerainty of the Margraves over their Greater Polish possessions situated to the north of the middle and lower stream of the River Noteć, that is on formerly Pomeranian territory (centred on Człopa), which could of course lay them open to the charge of treachery, since in Poland there was no consciousness or understanding of German claims (essentially rights) to the region of Pomerania. At the same time, in terms of German law, from 1231 Pomerania, including, of course, the territory of Nadnotecie still remaining in the thirteenth­ ‑century and – from a Polish perspective – of the former Pomeranian Zanotecie, remained within the gift of the German Empire within the fief of the Margraves of Brandenburg. Bieniak decisively rejects any reckoning in Poland in the thirteenth century with any kind of claim of the (in any case weakened) German state as a whole (Bieniak calls this the Empire), and even more of Brandenburg, the rulers of which as conquerors had no interest in the historical borders of Pomerania and did not even know them, but were driven only by brutal force and not by any legal titles. Of course, they ignored these, and the Nałęcz and Zaręba families did not see themselves as subordinate to anyone, just like everyone in Poland. Thus, they must be exonerated from participation in the crime of 1296. In this controversy, I wish to point out even more forcibly than previously (and, indeed, quite frequently) that the Nałęcz family, just like the Greater Poland princes (an example from 1253 is cited) and the knightly families settled in Pomerania (the Wedlow, Liebenow, Güntersberg, and Borkow families, 1296–1297, and the Święc family, 1307) knew the suzerain competences of the Margraves and recognized them – of course, under military pressure – over the castles and towns held by the Poles on the left bank of the Noteć (Santok–Drżeń–Wieleń– Czarnków–Ujście) along with their hinterlands, thus becoming Brandenburg and Polish subjects. In fact, the few sources do not permit such a maximum treatment of all the Brandenburg claims at the end of the thirteenth century, but that becomes obvious in subsequent decades of the fourteenth century, when it is by the intervention of the Margraves with support of the Nałęcz, Güntersberg, and Wedlow families that the territories and castles and towns of the eastern lands of Nadnotęcie are seized. That is why reference was made even to the rights raised by the Nałęcz family (of Ostroróg) to several villages in Puszcza Notecka near Drezdenko, most obviously because of those brought in the dowry of Małgorzata Nałęczówna of Szamotuły around 1330 to the German von der Osten lords in Drezdenko, when in 1408 they sold them along with their castle to the Teutonic Knights. On the margins of the article, I also offer a “gentle” defence of my position (also criticized by Bieniak) in the matter of the identification – in a contemporary entry in the annals of the Cistercians of Kołbacz – of Jakub “Kaszuby”, the principle perpetrator (and the only one known by name) of the regicide, with the German knight Jakub Güntersberg, who did, indeed, come from Kaszubia, since in 1296 he had left the service of the Dukes of Western Pomerania (from 1295, the Wołogoski dukedom), having up till then a fief in the lands near Stargard. In this case, “Kasube” was not an ethnic description, but only a geographical­­­‑political one.

Comparison of Environmental and Culture-Derived Bacterial Communities through 16S Metabarcoding: A Powerful Tool to Assess Media Selectivity and Detect Rare Taxa

To compare environmental and culture-derived microbial communities, we performed 16S metabarcoding of uncultured samples and their culture-derived bacterial lawns. Microbial communities were obtained from freshwater river samples representative of an anthropization gradient along a river stream. Their culture-derived bacterial lawns were obtained by growing aliquots of the samples on a broad range medium and on two different semi-selective media. The V3–V4 16S rRNA region was amplified and sequenced. The bacterial diversity of water samples decreased from the upper to lower stream sampling sites and, as expected, these differences were mostly suppressed by the culture step. Overall, the diversity of cultured-derived bacterial communities reflected selectivity of each tested medium. Comparison of treatments indicated that the culture selected both detected and rare undetected environmental species. Accurate detection of rare environmental bacteria of the Pectobacterium genus by 16S metabarcoding of the culture lawn was demonstrated. Interestingly, for abundant taxa, such as those of the Pseudomonas genus, the culture/environment ratio varied between sampled sites, indicating the difficulty of comparing cultured-derived taxa abundance between environmental sites. Finally, our study also highlighted media specificity and complementarity: bacterial communities grown on the two selective media, while selecting a small set of specific species, were mostly a subset of the bacterial community observed on the broad range medium.

Detection of Pharmaceutical Residues in Surface Waters of the Eastern Cape Province

Pharmaceuticals are emerging contaminants in the aquatic environments. Their presence poses toxicological effects in humans and animals even at trace concentrations. This study investigated the presence of antibiotics, anti-epilepsy and anti-inflammatory drugs in river water of selected rivers in the Eastern Cape Province in South Africa. Enzyme-linked immunosorbent assay was used for screening of sulfamethoxazole and fluoroquinolones antibiotics. The samples were collected in upper-stream, middle-stream and lower-stream regions of the rivers and effluent of selected wastewater treatment plants. Pre-concentration of the samples was conducted using lyophilisation and extraction was conducted using solid phase extraction (SPE) on Waters Oasis hydrophilic-lipophilic-balanced cartridge. The percentage recovery after sample clean-up on SPE was 103% ± 6.9%. This was followed by ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry. The detected analytes were sulfamethoxazole, erythromycin, clarithromycin and carbamazepine. Carbamazepine and erythromycin were detected in high concentrations ranging from 81.8 to 36,576.2 ng/L and 11.2 to 11,800 ng/L respectively, while clarithromycin and sulfamethoxazole were detected at moderate concentrations ranging from 4.8 to 3280.4 ng/L and 6.6 to 6968 ng/L, respectively. High concentrations of pharmaceuticals were detected on the lower-stream sites as compared to upper-stream sites.

Zooplankton of the Kama river, the fauna composition and structure, the assessment of the ecological state of the environment

The paper deals with the study of zooplankton in the lower stream of the Kama river, the largest tributary of the Volga, which has important economic importance for the European part of Russia. The obtained results allowed to establish the summer composition of zooplankton fauna of the studied reservoir, to determine the quantitative characteristics of the communities. 61 taxa belonging to 3 types were identified: Rotifera, Arthropoda (Cladocera, Copepoda groups) and Mollusca (Bivalvia). The average species density in the study area is 10 1 taxa per station. The average biomass in the study area was 0,679 0,434 g/m, the average number was 49,50 8,01 thousand specimens/m. The average daily zooplankton production was 0,043 0,020 g/m. The biocenotic analysis has allowed to allocate five types of communities with the dominance of the major species of rotifers, cladocerans and copepods in the study area. The two-factor analysis showed that the structure of communities is more influenced by the local features of biotopes than the general conditions at the study sites. The wellbeing index indicates that the communities of zooplankters in the lower stream of the Kama river are in a state of near stress. The environmental assessment on the composition and structure of types of indicators is possible to attribute this body of water to moderately polluted water (-mezosaprobic zone).

Mercury pollution of sediments from the river Tisa (Serbia)

Mercury (Hg) has been listed as a global high priority pollutant by many international organizations due to its mobility and persistence in the environments and high toxicity to organisms. This research was conducted with the aims to determine: (i) total Hg content (THg) and its spatial distribution in sediments of river Tisa along the river course, (ii) possible sources of THg and (iii) degree of THg pollution in sediments from the river Tisa through different criteria. Total Hg in the sediments ranged from 0.07 to 0.49 mg kg-1, with mean ? S.D. value of 0.26 ? 0.10 mg kg-1. The highest mean value of THg (0.30 mg kg-1) was found in the lower stream, while the lowest (0.13 mg kg-1) was found in the tributary. According to Principal Component Analyses (PCA) strong positive loading of metals in all parts of the river Tisa is mainly controlled from the same sources. These sources are related to anthropogenic activities based on calculated Enrichment Factor (EF) values. Total Hg are higher than background value. According to the Republic of Serbia official standard, THg values of river Tisa sediments were within the range of maximum permissible values. Compared with National Oceanic and Atmospheric Administration (NOAA) guideline, 80.49% of sediment samples indicated that THg in the river Tisa sediments represented minimal and possible risk towards the living organisms. Integrating the results of pollution assessment, it could be concluded that THg in river Tisa sediments in Serbia demonstrates considerable contamination according to Geoaccumulation Index (Igeo), and Contaminant Factor (CF), and high pollution risk according to Potential Environmental Risk Index (PERI).

ON THE PROBLEM OF WATER TEMPERATURE INFLUENCE ON SEASONAL GROWTH OF JUVENILE COHO SALMON ONCORHYNCHUS KISUTCH IN THE LOWER REACHES OF THE BOLSHAYA RIVER IN 2007–2018

The water temperature difference between relatively cold and warm years is not significant for somatic growth and number of sclerites in the external zone of scale out of the annual ring («plus zone») for yearlings of coho salmon in the lower stream of the Bolshaya River (West Kamchatka). The temperature effect is ambiguous and depends on month. In 20 days since May 15, number of the sclerites formed in this zone is definitely higher in warm years (0.77 sclerites, on average) than in cold years (0.51 sclerites), but in 120 days the difference almost disappears: 10.39 sclerites in warm years and 10.13 sclerites in cold years. So, each scleritis forms in approximately 10.4 days during June-August, no matter either warm or cold year it is. In September, the number of sclerites in the «plus zone» could be even smaller in some warm years than in some cold years. The temperature effect absence can be explained by low temperature in the river during the whole period from May to October (6.44 о C in May, 8.80 о C in June, 11.83 о C in July, 12.25 о C in August, 10.10 о C in September, and 6.33 о C in October, on average), that is close to the lowest limit of the optimal temperature range for coho juveniles (11.5–16.8 о C). Difference of the yearlings body length is also insignificant: in the period of 20–90 days from May 15 of 2007–2018, their mean body length increased in 2–5 mm more in the years with temperature above the norm in July than in the years with temperature below the norm, but within the period from middle May to late August the increments values coincide frequently for both types of years. All differences in the body length and number of sclerites between the coho yearlings in warm and cold years do not exceed the level of statistical errors. That’s why merging of all materials on juvenile coho salmon in the Bolshaya River is recommended, without their separation to cohorts of warm and cold years.