Types Of Water Bodies Research Articles

Geochemical characteristics and water quality assessment in the Mt. Changbai volcanic field, Northeastern China

The chemistry of groundwater is an important determinant of water quality, which is vital to human health and the ecosystem. It is estimated that 10% of the worldwide population lives in the vicinity of an active volcano; in these regions, the quality of the water could greatly affect crop yield and soil fertility. The Mt. Changbai volcanic field (CVF), located on the border between China and North Korea, is the most well-preserved typical forest ecosystem in eastern Asia, providing various ecological services to human beings. Many types of water bodies, including hot springs, cold springs, and surface water bodies (e.g. rivers and pools) are distributed in the volcanic field. In this study, the geochemical characteristics of these water types, the quality of the water for irrigation purposes, as well as the water quality-related natural mechanism of the water chemistry in the CVF were systematically studied. The results indicate that the hydrochemical characteristics of the water samples in the CVF show the obvious difference between the volcanic cone and the peripheral areas. Significant spatial variation in the water quality was found in the CVF, where water in the peripheral areas was found to be of better water quality than that in the volcanic cone. The hot spring water in the CVF is not only unsuitable for drinking, but also unsuitable for irrigation. Water-rock interactions, ion exchange, and the addition of magmatic volatiles as well as atmospheric and anthropogenic sources are the main source and controlling factors of ions in the water in the CVF. The results of this study can be used as a reference for the sustainable management of groundwater resources in dormant volcanoes.

Water Inrush Mechanism and Treatment Measures in Huali Highway Banyanzi Tunnel—A Case Study

In the process of tunnel construction, the water inrush disaster is one of the main engineering geological disasters. In karst strata, different types of water-bearing structures or karst water bodies develop and occur in the soluble rock layer, and tunnel excavation easily forms new drainage channels, resulting in water inrush in the tunnel. Based on the project of the Huali Highway Banyanzi Tunnel, this paper studies the water inrush characteristics, water inrush mechanism, and treatment measures of the karst tunnel. According to the basic data, combined with field investigation, data monitoring, geological radar detection, tracer test, and numerical simulation, the characteristics and hydrogeological conditions of the tunnel water surge were investigated and analyzed. In addition, the mechanism of tunnel water surge was further summarized. Moreover, the tunnel water-gushing management measures are optimized and verified based on the tunnel water spraying mechanism.

NEW FINDINGS OF THE NAKED FILOSE AMOEBAE IN NATURAL BIOTOPES OF UKRAINE

We have identified 10 species of naked filose amoebae in different types of water bodies in Ukraine. Original morphological descriptions have been compiled for all species. The most common species are Arachnula impatiens, Penardia mutabilis, Nuclearia delicatula, Biomyxa vagans, Vampyrellidium perforans, Nuclearia flavocapsulata, the least common are Vampyrella lateritia, Lateromyxa gallica, Leptophrys elegans, Leptophrys vorax. Established ecological groups of these protists in relation to the abiotic factors of the aquatic environment: euryoxidic (N. delicatula, N. flavocapsulata, A. impatiens, P. mutabilis, L. elegans, L. vorax, V. lateritia), stenooxidic (V. perforans, B. vagans, L. gallica), stenobionts (A. impatiens, V. perforans, B. vagans, L. gallica) and those that withstand a wide range of permanganate oxidation values (N. delicatula, N. flavocapsulata, P. mutabilis, L. elegans, L. vorax, V. lateritia). The largest number of species of these protists is observed in rivers (8 species) and floodplains (7 species), the smallest – in swamps (3 species); 5 species of filose amoeba were found in the lakes. We encountered P. mutabilis only in rivers, B. vagans in swamps, and V. perforans in floodplains. L. elegans, L. vorax species, which can be considered eurytopic, occurred in all types of reservoirs. The largest share of common species of naked amoebas is observed between rivers and floodplains (0.80), rivers and lakes (0.77), floodplains and lakes (0.67) and lakes and swamps (0.50), the smallest – between floodplains reservoirs and swamps (0.40) and rivers and swamps (0.36). According to the species composition of naked filose amoebae, two species complexes are distinguished: swamp and floodplain, which includes species that mainly occur in rivers and in reservoirs located in river valleys. The species complexes of rivers, floodplains and swamps are influenced to a greater extent by water temperature and the concentration of organic substances dissolved in water, and to a lesser extent by the concentration of oxygen dissolved in water. The species composition of naked filose amoebas of rivers and floodplains is associated with a higher temperature and a higher content of organic substances dissolved in water compared to the species composition of swamp amoebas.

A simple multilevel sampler for synchronous collection of stratified waters.

Stratified water collection plays a crucial role in water quality monitoring, as most water bodies are not perfectly mixed systems. In order to precisely collect stratified waters, we developed an inexpensive, simple, and high-resolution sampler to simultaneously collect and measure physical and chemical parameters along vertical water profiles. The water sampler predominantly consists of two parts: (1) an apparatus for measuring sampling depth below the water and (2) water sampling units secured below the water. Proof of concept water sampling was performed in Caohai wetland (Southwest China) at 40cm intervals, as sampling depth and interval are adjustable. Stratified waters in four sampling sites were characterized by markedly different levels of major and trace elements as well as physicochemical parameters. Results indicate this simple multilevel sampler to be a cheap, precise, and portable option for simultaneously collecting water samples at different depths in a wide array of water body types.

Communities of Benthos Invertebrates of the Kiliya Delta of the Danube River

The communities of benthos invertebrates occurring in various biotopes of the water bodies, watercourses, and coastal zone of the Kiliya delta of the Danube River were distinguished based on the similarity of their species composition. It has been found that mainly water salinity is responsible for the formation of their physiognomy and hierarchic organization in the Kiliya delta of the Danube River, whereas the types of bottom sediments and the types of water bodies are responsible for the formation of their components. The levels of hierarchic organization of benthos communities are as follows: the lowest level is formed by primary mosaic communities occurring in various water bodies and on various types of bottom sediments, the next level is formed by the united communities distributed on various types of bottom sediments in fresh or brackish water bodies, whereas the highest level is formed by the communities of the Kiliya branch and the Danube River delta on the whole. It has been shown that the discreteness and continuality of benthos communities in the Kiliya delta of the Danube River are formed due to the development of both fresh and brackish species.

Study of mosquito (Culicidae) larvae and characterisation of water bodies in urban and periurban areas

Abstract Urbanisation has modified the distribution and community composition of mosquito species (Culicidae). Habitat disturbance may increase the risk of loss of species diversity and the occurrence of vector-borne diseases. Studies on the presence of larvae and the eco-physicochemical characteristics of water bodies near urban areas provide information on the risk of these diseases. In this study, the presence of larvae in different types of urban and periurban water bodies in Villahermosa City, Tabasco, Mexico was analysed. The eco-physicochemical characteristics of each collecting site were measured. A total of 67 528 larvae were collected, 1366 were identified to species, and 15 species were observed. Although Culex spp. were the most dominant species, Anopheles albimanus was the only species present in all habitats. Despite the large variability in the parameters measured (especially in physicochemical parameters; e.g., pH, electrical conductivity, total dissolved solids), differences were observed among the breeding sites. Weak correlations were found between eco-physicochemical parameters and species presence. Predators may have a major role in determining community processes in the region. Habitat disturbance may be responsible for eco-physicochemical variations altering mosquito community composition, resulting in the loss of endemic mosquito species and increasing the risk of vector-borne diseases in Villahermosa.

Жамбыл облысының микрогидронимдерін зерттеудегі жасанды және табиғи су көздері атауларының көрінісі

A large number of natural and artificial water sources are found on the territory of Zhambyl region. This is due to the fact that in the territory located in the mountainous region, the names of rivers, lakes, streams, wells with rich reserves of water resources are often found, and the nature of hydrological objects is clearly indicated. It can be said that the terms defining geographical names that characterize natural water sources have an ecological and geographical basis. Natural water sources have played an important role in the economy and provide extensive geographical information from history. From modern historical and archaeological data it can be seen that the first human settlements were located near water bodies. The article analyzes specific data on the manifestations, formation and features of the names of artificial and natural water sources in the study of microhydrogems of the Zhambyl region. The names of water bodies (hydronyms) are based on hydrographic terms. With the help of the terms contained in the hydronyms, it is possible to determine the type, nature and geographical features of water bodies. Toponymic analysis, geoinformation methods of differentiation and drawing conclusions were used in the study of microhydronyms of Zhambyl region.

Soxhlet Extraction of Spirogyra sp. as an Energy Source and Physicochemical Characterization of Produced Biodiesel

Due to industrialization demand of energy is increasing and hence to meet the demand without any compromise in growth and development, alternative source of energy needs to be found. The best alternative source is biofuels which are extracted from organic compounds. Algae are aquatic organisms almost available in every type of water bodies and considered as potential candidates for biodiesel productions at large scale. In present study, an experimental set –up was designed to produce algal oil through transesterification process. The Soxhlet extraction method is employed as an oil extraction method. The solvent utilized for oil extraction method is n-hexane, petroleum ether and mixture of both solvents to extract the algal oil. Also the oil extracted from the algae is characterized to identify the suitability of algal biodiesel as a potential biofuel for internal combustion (IC) engine. The characterization revealed that physicochemical properties of obtained biodiesel were in permissible range in comparison with standard diesel fuel.

Contextualising the bizarre: The integrated functioning of rib puncture as an antipredator defence in the Iberian ribbed newt (Pleurodeles waltl)

Abstract Numerous prey traits are the result of the pervasive evolutionary pressure imposed by predators. Mirroring their fundamental role in the fitness of prey, some antipredator defences can evolve into elaborate strategies. Such is the case of the Iberian ribbed newt (Pleurodeles waltl), a semiaquatic urodele that inhabits multiple types of inland waterbodies in central and southern Iberian Peninsula and north‐western Africa. It possesses sharp, protractile ribs, which can thwart predators by emerging through skin ‘warts’ they pierce, becoming impregnated with the toxicants these warts produce, and making the newts difficult to swallow. Plus, the orange colour of these warts contrasts with the predominantly dull dorsum. In this work, I studied the interactions between the number of these warts, the saliency of wart colour against dorsum colour of each individual (i.e., the difference in colour between the warts and the dorsum), rib response time (i.e., the time needed for the ribs to emerge in response to a standardised stimulus), body size, and locomotor performance in males and females in either their aquatic or terrestrial stage. I also conducted a field experiment to determine whether predators more frequently attacked plasticine models with conspicuous or inconspicuous warts. I found that wart colour saliency functions as a decoy, attracting predator attacks towards this well‐protected body part. Plus, many of the antipredator defences studied, namely the number of warts, their colour saliency, rib response time, body size, and locomotor performance, were interrelated. Accordingly, more salient warts indicated a faster rib response, suggesting that these defences are coordinated with each other. Plus, locomotion was considerably slower in the terrestrial than in the aquatic stage. Moreover, warts were more salient, and thus more efficient attracting predator attacks, in newts in the slower terrestrial stage. However, rib response was faster in the aquatic stage, which coincides with the newt's activity peak, and therefore with the height of its conspicuousness to predators. Remarkably, faster newts display less salient warts and a slower rib response, which suggests a trade‐off between both defences. Nonetheless, some of these trends are reversed in females, among which faster individuals also display a faster rib response. This could be a likely consequence of reduced predation pressure. These results further the understanding of how prey integrate and tune multiple antipredator defences according to factors that influence predation pressure, such as sex and life stage.

Phytoplankton-Zooplankton Community Structure in Coal Mining Subsidence Lake.

Land subsidence from coal mining has shaped new artificial aquatic ecosystems, these subsidence lakes are known for their restricted ecological system, water pollution, and extreme habitat conditions. However, knowledge concerning the community structure of plankton in these types of water bodies is still limited. Therefore, both phytoplankton and zooplankton communities' abundance, distribution, and diversity, as well as relations of these communities to physicochemical water quality variables were analyzed, alongside the interaction between phytoplankton and zooplankton groups. The results indicate zooplankton abundance was 842.375 to 186,355.0 ind./L. Biomass ranged from 0.3408 to 10.0842 mg/L. Phytoplankton abundance varied between 0.541 × 106 cell/L and 52.340 × 106 cell/L while phytoplankton wet biomass ranged from 0.5123 to 5.6532 mg/L. Pearson correlation analysis revealed that both the zooplankton and phytoplankton total densities were significantly correlated with nutrients (TN, TP, PO43-) and CODcr; zooplankton abundance was significantly correlated with phytoplankton abundance. According to the biodiversity index of Shannon-Wiener, both phytoplankton and zooplankton revealed less biodiversity in the subsidence water region than in the Huihe river system and Xiangshun canal, with values ranging from 0.20 to 2.60 for phytoplankton and 1.18 to 2.45 for zooplankton; however, the phytoplankton community showed lower biodiversity index values compared to the zooplankton community. Overall, the knowledge gleaned from the study of plankton community structure and diversity represents a valuable approach for the evaluation of the ecological conditions within the subsidence lakes, which has significant repercussions for the management and protection of aquatic environments in mining areas.

Hydrological classification of non‐perennial Mediterranean rivers and streams: A new insight for their management within the water framework directive

AbstractClassification of natural flow regimes of non‐perennial rivers and streams (NPRS) is an incipient field of research. NPRS represent approximately 70% of the total Mediterranean rivers and are expected to increase in the next decades as a result of climate change. Due to the ecological importance of NPRS and the need to improve national ecological assessment methods within the scope of the Water Framework Directive (WFD), this paper aims to classify the hydrological regime of 69 non‐regulated streams, testing several hydrological indices related to the magnitude, frequency, duration, timing, and rate of change in periods of flow cessation. Using daily flow records, a total of 315 indices were calculated and their relationships were examined with Principal Component Analysis (PCA) for different thresholds used to define zero‐flow condition (0, 1, 2, and 5 L/s). Redundancy analysis identified five indices that better describe the patterns of hydrological variability in Mediterranean NPRS: number of days per year without flow, annual percentage of months without flow, mean daily annual flow, coefficient of variation of Julian date of the annual start of zero‐flow and annual rise rate. Using these indices, a self‐organizing map (SOM) was trained in order to categorize the NPRS into three groups with similar hydrological features. The results of this study provide a statistically‐based hydrological classification of NPRS in Mediterranean environments. We expect that this classification will provide useful insights to water authorities to improve the assessments of the ecological status in this type of water bodies.

Molecular Identification of Protozoan Sarcocystis in Different Types of Water Bodies in Lithuania.

Representatives of the genus Sarcocystis are unicellular parasites having a two-host life cycle and infecting mammals, birds, and reptiles. Until now, Sarcocystis spp. have been mainly investigated in definitive and intermediate hosts. Only a few studies have been conducted on the detection of Sarcocystis parasites in water samples. The aim of this research was to examine whether the prevalence of Sarcocystis spp. parasitizing farm animals varies in different types of water bodies. Water samples (n = 150) were collected from the entire territory of Lithuania, dividing water bodies into five groups (lakes, rivers, ponds/canals, swamps, and the inshore zone of the territorial Baltic Sea area). One-liter samples were filtered and subsequently analyzed using nested PCR. At least one of the analyzed Sarcocystis spp. (S. arieticanis, S. bertrami, S. bovifelis, S. capracanis, S. cruzi, S. hirsuta, S. miescheriana, and S. tenella) was determined in all examined samples from water bodies. No significant difference in Sarcocystis spp. prevalence between different types of water sources was detected. Our research proved that selecting appropriate primers is important for the accurate identification of parasites in samples collected from water bodies.

Monetized Estimates of the Ecosystem Service Value of Urban Blue and Green Infrastructure and Analysis: A Case Study of Changsha, China

Urban blue-green infrastructure (BGI) forms the basis of a regional ecosystem. Quantitative calculations can identify the weak points of a typical ecological environment, which is helpful for providing a basis for the spatial planning and ecological environment protection of developing cities. Currently, assessment of BGI ecosystem services focuses on local temperature, climate, and entertainment aesthetics, and the integrity of ecological indicators needs improvement. The assessment is usually conducted within large blue-green areas such as parks and rivers, and street greening is typically ignored. Roof gardens and unmanaged blue-green spaces also have ecosystem service functions. Therefore, our study aimed to extract the basic design distribution of urban blue-green spaces more accurately and monetize the value of its ecosystem services. Changsha, one of the top ten ecologically competitive cities in China, was the research focus. First, four types of BGI, forest, grassland, wetland, and waterbody, were extracted using remote sensing images and ArcGIS10.8. Second, the adjusted value coefficient was used to quantify the service value and geographic spatial distribution of the four BGI ecosystems in monetary terms. The results showed that in 2020, the total economic value of ecosystem services (ESV) generated by BGI in the study area was CNY 36.25 billion. Among ecosystem services, forest land climate regulation and waterbody hydrological regulation accounted for the largest proportion, at CNY 6.543 and 15.132 billion, respectively. The urban center had the weakest climate regulation capacity, and the Xiangjiang River Basin had the strongest hydrological regulation capacity. The urban center had the lowest ESV, thus requiring the attention of urban planners in the future. This study evaluated and optimized the distribution of BGI in Changsha according to the ESV of the existing BGI to help improve the ESV of the city center and create a green, ecological, and healthy city.

A diatom-based predictive model for inferring past conductivity in Chadian Sahara lakes

For decades, diatoms have been recognized as powerful bio-indicators of modern water quality. They have also been utilized in the design of transfer functions, which can be applied to diatom assemblages in lake sediment cores to infer aspects of past lake hydrochemistry and estimate variables that can be incorporated into paleohydrology models. The Ounianga lakes, in the heart of the Chadian Sahara, possess unique and well-preserved sediment records that extend back beyond the middle Holocene. Today, the lakes display a range of hydrochemical conditions, from fresh to hypersaline. Mainly fed by fossil groundwater that originates in the Nubian Sandstone Aquifer System, measured conductivity across these lakes varies from 217 to 352,000 µS cm−1, values that are influenced by factors such as hydrology, local geomorphology (e.g., depth and area), and aquatic vegetation. Although these lakes have been on the UNESCO World Heritage List since 2012, they have never been studied in detail because they are located on the fringes of the Chadian Sahara. The distribution of diatom taxa in the lakes today is closely linked to water-column physical and chemical conditions, especially conductivity. Whereas each lake has particular features that influence its diatom flora, diatoms across a conductivity gradient enabled identification of three distinct waterbody types, freshwater lakes, meso-saline to hyper-saline lakes, and freshwater springs. Relationships between diatom species distributions and environmental variables were examined using multivariate analysis, which revealed that conductivity is the variable that explains most of the variance in the diatom flora. We used modern diatom assemblages from the lakes to develop a predictive model (transfer function) for conductivity, using the weighted averaging method. Our conductivity prediction model is strong, with a coefficient of determination (R2) of 0.89 between estimated and measured values, and a value of 0.78 using jackknife estimates of prediction. This study better constrained conductivity optima and tolerance values for diatom species found in the Ounianga lakes, thereby enabling development of a model that will yield better inferences for past conductivity, using diatoms from lake sediment records in the region.

Spatiotemporal Characteristics of Dissolved Oxygen and Control Mechanism of Hypoxia (Low Oxygen) in the Watershed-Coastal System in Fujian Province

Dissolved oxygen is a key parameter to measure water environment quality and ecosystem health. Currently, the problem of hypoxia (low oxygen) is prominent in coastal areas in China, but there is a lack of research on the spatiotemporal characteristics of dissolved oxygen and the control mechanism of hypoxia in the watershed-coastal system. Based on the data of 135 surface water (including estuaries) and 66 coastal water monitoring sites in Fujian Province from 2011 to 2020, this study analyzed the spatiotemporal variation pattern of dissolved oxygen at seasonal and interannual time scales. The data of hypoxia (10% quantile, corresponding to 67% saturation) were selected to study the characteristics and control mechanism of hypoxia in four types of water bodies (i.e., rivers, reservoirs, estuaries, and coastal waters) using mathematical statistics and a random forest model. The results showed that the dissolved oxygen saturation was the highest in the coast[(98.2±10.2)%] and the lowest in the estuary[(79.2±17.9)%]. Compared with that in the 12th Five-Year Plan (2011-2015), the frequency of hypoxia detection in rivers and reservoirs in the 13th Five-Year Plan (2016-2020) was significantly reduced, but the change in estuaries was not significant. Counting the points with hypoxia detection, the multi-year average hypoxia detection frequency of rivers and reservoirs was highest in autumn, and the frequency of estuaries was highest in summer. Hypoxia in reservoirs and estuaries was the most prominent but with different mechanisms. Specifically, hypoxia in reservoir reaches was related to summer runoff carrying large amounts of organic matter input, stratification leading to continuous oxygen depletion in the bottom water, and vertical mixing or discharge through dams in autumn, whereas hypoxia in estuaries was associated with strong pollution inputs and reductive materials. Systematic management and regionalized control mechanisms need to be established to further strengthen watershed-coastal pollution abatement to help mitigate eutrophication and hypoxia problems.

Shellfish as a bioremediation tool: A review and meta-analysis

Over the last century, human activities have increased the amount of nutrients inputs to terrestrial and aquatic ecosystems. These activities have altered nitrogen (N) and phosphorus (P) cycling, causing substantial changes in ecosystem function such as provision of clean air and water. Strategies that reduce and remove excess nutrients are urgently needed to remediate impacted systems. Reef-forming shellfish (oysters and mussels) can play a crucial role in nutrient cycling, particularly in N removal from aquatic systems by providing substrate for microbial colonisation and enhancing microbial denitrification in the surrounding sediments. However, the potential for shellfish to enhance nutrient cycling (and denitrification) will likely vary spatially and in response to several environmental factors. Here, we used 1) a qualitative analysis to review nutrient processes occurring on shellfish; and 2) a meta-analysis to evaluate the influence of shellfish on benthic metabolism and nutrient cycling in surrounding sediments, and how that is influenced by environmental factors such as grain size, seasonality, water body type, and tidal position. Overall, we found that shellfish increased oxygen consumption, with consequent release of ammonia (NH4+) and phosphate (PO43-) from shellfish and their surrounding sediments. These parameters did not depend on grain size, water body type and tidal height, but the release of PO43- was variable between seasons, being highest during summer and autumn. Shellfish presence also enhanced denitrification measured as dinitrogen gas (N2) efflux on both reefs and sediments. Denitrification was highest in lagoons; in sandy sediments; and during the warmest season (summer). Thus, our findings highlight that environmental context can mediate the effects of shellfish reefs on sediment function. This information is important for managers seeking to use these animals as an effective bioremediation tool.

Ecological and faunal characteristics of helminths of wetland birds in North-Western Uzbekistan

The article studies some faunistic features of helminths of wetland birds in the ecological crisis zone in North-Western Uzbekistan. Parasites of wetland birds collected in the basin of the lower reaches of the Amu Darya during the hunting seasons of 2018–2022 were used as material for this work. 500 individuals of birds representing 39 species from 24 genera, 13 families and 9 orders were examined using the parasitological dissection method. The article discusses the distribution and ecology of the helminths in the studied groups of birds. A total of 112 helminth species were identified in the region – 28 species belong to the class Cestoda, the class Trematoda is represented by 57 species, Nematoda – 23 and Acanthocephala – 4 species. 92 species of heminths were identified in the study area for the first time. The work provides original data on the structure of the helminth fauna from 9 orders of wetland birds. Various paths of helminth transmission in the circulation of infection were specified. The researchers identified four ways parasites use to enter their definitive host: helminths penetrate the host’s body when the latter eats other organisms, intermediate or reservoir hosts of helminths, which are part of the definitive’s host’s diet; helminths enter the host as mechanical impurity to food or water; they make active efforts to penetrate their host; helminths are transmitted by the intermediate host when the latter forages on the definitive host. Most of intermediate hosts for representatives of the class Cestoda were crustaceans – inhabitants of different types of water bodies; Oligochaeta are also included here as second or reservoir hosts. The development of trematodes occurs with the participation of aquatic molluscs acting as the first intermediate host. Various species of insects, fish, amphibians, reptiles and small mammals were identified as the second hosts. Nematoda use a wider range of intermediate hosts (Oligochaeta, crustaceans, insects – aquatic and terrestrial). Fish and amphibians were registered as the second and reservoir hosts of nematodes. The food chains of individual orders of wetland birds largely determine the composition of helminths parasitising them and are the main factor in the formation of their helminth fauna. These processes undoubtedly occur in time and space under the strict control of environmental factors.

Physicochemical parameters of water in earthen ponds and concrete water storage reservoirs in Bakolori irrigation project, Zamfara state, north western Nigeria

Physicochemical Parameters of large Earthen Ponds and Concrete water storage reservoirs (CWSRs) of Bakolori Irrigation Project (BIP) were investigated from March 2019 to February 2020. Four sampling stations were randomly selected from the two water body types. Air and Water Temperature, Dissolved Oxygen (DO), pH, Electrical Conductivity (EC), Water Depth, Total Dissolved Solids (TDS), Transparency & Salinity were determined in situ, while water samples were collected monthly from the eight sampling stations and taken to the laboratory for analysis of Alkalinity, Hardness, Nitrate-N and Phosphate-P. The data collected were arranged on the bases of two seasons (dry & wet) and five sub-seasons, namely: Early dry (Oct - Dec); mid dry (Jan & Feb); late dry (March - May); Early rainy (June & July) and flood period (Aug & Sept), and subjected to T test analysis using Minitab statistical package. Results were compared with the water quality standards for Human consumption, aquatic life and fish production aquatic life and aquaculture. Results showed that with the exception of high Turbidity (low transparency) due to mud & debris in the water storage reservoir in some sub seasons, the water bodies were suitable for Aquatic life and Aquaculture. But partly unsafe for human consumption. The study recommends continuous assessment of the water bodies for physicochemical parameters. It further recommends the use of several water storage reservoirs for mudfish (such as Clarias and Hetrobranchus species) production instead of leaving them redundant as observed during the study period.

SMURF: A Fully Autonomous Water Surface Cleaning Robot with A Novel Coverage Path Planning Method

In recent years, more attention has been paid to water surface environment protection. Current water surface waste cleaning mainly relies on manual operations, which are low-efficiency and dangerous. Therefore, in this paper, we design a fully autonomous water surface cleaning robot, SMURF, which achieves high-efficiency water surface cleaning without human operation and adapts to be used in various types of real-world water bodies. In addition, we propose a novel coverage path planning method on water surfaces and an improved nonlinear model predictive controller. The real-world experiment shows that SMURF works well in different kinds of water bodies and achieves much higher efficiency than traditional water surface cleaning methods.

PRESENT STATUS AND FUTURE FISH PRODUCTION POTENTIAL OF SADAR UPAZILA OF JHENAIDAHA DISTRICT, BANGLADESH

An investigation on the present status and future fish production potential of Jhenaidaha Sadar Upazila of Jhenaidaha district was carried out from July 2001 to June 2002. Jhenaidaha Sadar Upazila is endowed with a large variety of waterbodies that can be used to produce a considerable amount of fishes. The present investigation was undertaken to know about the present status of fish production at different types of waterbody and make a potential to increase fish production in future in Jhenaidaha Sadar Upazila. The total fish production of all the waterbodies of Jhenaidaha Sadar Upazila was found to be 1,365.09 mt. Analyzing the present status of fish production, a five-year fish production potential has been prepared and after five year, the fish production target is estimated to be 3,289.62 mt. Among the different waterbodies, the highest fish production was found in pond sector (1,411 kg ha-1). This study suggested the proper utilization of the available fisheries resources and some recommendations have also been made to increase fish production in Jhenaidaha.