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Interaction among macrobenthic molluscan diversity of river Ganga and ecological variables by using multivariate indices
Abstract
Ganga river is one of the important water bodies harbouring different aquatic communities especially sedentary benthic organisms. We determined several macrobenthic molluscan faunas including 24 species comprising of 18 gastropods and 6 bivalves. The maximum species diversity with a value of 2.08 was recorded during monsoon, whereas the species richness was found to be highest (0.809) during winter. To determine the correlation between the physicochemical parameters of water, sediment and macrobenthic organisms, we have employed the canonical correspondence analysis (CCA) for middle, lower and estuarine stretches of river Ganga. The water CCA components, CCA1 and CCA2, explained 48.64%, 47.01%, 45.11% (p = 0.568, 0.019 and 0.417) and 18.11%, 26%, 23.9% (p = 0.98, 0.292 and 0.978) between the environmental parameters and macrobenthos correlation, respectively. Similarly, the CCA components for soil showed a percentage of 41.82%, 41.58%, 24.73% in CCA1 (p = 0.156, 0.026 and 0.922) and the CCA2 revealed a percentage value of 24.23%, 25.58%, 23.59% (p = 0.446, 0.174 and 0.488) of the mentioned parameters. The present study explored a dual relationship between the organisms and environmental factors according to their abundance and distribution pattern.
... 7 Freshwater Mollusca is found in all aquatic habitats such as rivers, lakes, streams, swamps, springs, temporary ponds, drainage ditches and other water bodies. 6 Groombridge (1992) non-marine molluscs have experienced the highest number of recorded extinctions, with a total of 284 species becoming extinct within the past 300 years. 16 There are about 80 species of freshwater molluscs including 30 species of bivalves and 50 species of gastropods are known from Nepal (Budha 2010). ...
... It exhibits excellent biocompatibility, biodegradability, and antimicrobial properties, making it valuable in various industrial and biomedical applications (Rinaudo et al. 2006). 6 Chitosan: ...
Northeastern India's great biological diversity has earned it a reputation. For this study, Filopaludina bengalensis were selected. The aim of the present study was to investigate the presence of phytochemicals of the selected Mollusca. Morphoanatomical study on Filopaludina bengalensis was carried & different images was formed. Mollusca shells were digested with HCl. Centrifugation was done to take out the insoluble matter. Along with that snail enzyme was collected by starving it for days. Isolation of N-Acetyl D-glucosamine was done with extracted chitin and snail enzyme. FTIR analysis of Chitin & N-Acetyl D glucosamine was determined. With the help of graph peak was studied, N-acetyl D- glucosamine & chitin was compared with standard component. Our findings provided evidence that crude aqueous and organic solvent extracts of these tested snail contain medicinally important bioactive compounds and it justifies their use in the traditional medicines for the treatment of different diseases.
... An ecological platform's accumulation of biological and physicochemical reactions is referred to as a bioindicator. Accordingly, benthic organisms are frequently used as bioindicators to evaluate how pollution affects aquatic ecosystems (Roy et al., 2022). Because they mineralize, encourage, and mix the oxygen flux into the sediment, macrobenthos play a crucial role in aquatic ecosystems by recycling organic matter. ...
The present study was carried out with the purpose of monitoring the recent
zooplankton and benthic macroinvertebrate assemblage and evaluating the
ecological state of Wadi El-Rayan Lakes, which are solely dependent on waste and
agricultural discharging water through the El-Wadi drain. The study commenced in
November 2018 and ended in July 2019, during which water samples were collected
to measure environmental parameters. The Shanon-Wiener diversity index (H`) and
Bray-Curtiz similarity index were applied. The Biological Monitoring Working
Party (BMWP) and Average Score Per Taxon (ASPT) were also applied to the upper
and lower Wadi El-Rayan Lakes for the first time. In the upper lake, forty adult
zooplankton taxa were identified, while in the lower lake, the number of species
declined dramatically to nineteen adult species and three immature stages. Rotifera
dominated the upper lake, whereas Copepoda dominated the lower lake. A total of
ten macro-invertebrate taxa were identified in the upper lake, whereas thirteen were
identified in the lower lake. The benthic communities of the upper lake consist of
Mollusca, Annelida, and Arthropoda, while those of the lower lake comprise
Arthropoda, Mollusca, Annelida, and Coelentrata. Although the upper lake
displayed a poor to medium ecological status, the lower lake exhibited diverse
populations, indicating a better ecological condition. The BMWP score of the upper
lake was 41, suggesting a moderate status, while the lower lake's score was 59,
indicating a moderate ecological status as well. The ASPT values indicated a
moderate ecosystem status for both the upper and lower lakes. This study established
a baseline reference for future monitoring, and calls for stakeholders to take special
care of this crucial protectorate to mitigate uncontrolled activities.
The present study deals with biomonitoring to know mollusc species as an indicator. In the present study, presence, absence and abundance of particular gastropod and bivalve species were identified in the different banks of river Ganga. The study was carried out at two experimental sites, Sodepur (Exp-1) and Khardah (Exp-2), West Bengal, India as the area exhibits a major sewage water outfall in the river compared with upstream control site, Kalyani (Cont-1) and downstream control site, Batanagar (Cont-1). The present biomonitoring shows qualitatively and quantitatively that in experimental no mollusc species were observed near the wastewater discharge area into the bank of river Ganga at Khardah while both sites of the sewage discharge area into the bank of river Ganga at Sodepur particular gastropod Bellamya sp. were observed when compared to control area. The highest variety and total nos of gastropods and bivalves (280 nos) were recorded in the upstream at Kalyani and lowest variety and total nos of only gastropods (150 nos) were recorded in the downstream at Batanagar. The present biomonitoring work was a preliminary observation to know sensitive and tolerant or accumulator mollusc species in the bank of river Ganga from a stretch of Kalyani (upstream) to Batanagar (downstream) in between urban wastewater discharge area (Sodepur and Khardah). Further researches must be relevant in relation to biomarker assessment with the physico-chemical factors and stress tolerant detoxification mechanism of particular mollusc species.
Freshwater mollusc diversity has repeatedly been found to peak in lowland stagnant waters, which are highly exposed to human-made degradation and the spread of non-native species. Despite the increasing loss of these habitats, little is known about the main predictors of their mollusc diversity patterns. Therefore, we aimed to determine the environmental drivers of mollusc assemblage variation between and within sites by sampling 62 water bodies in the Dyje River floodplain (south-eastern Czechia). We measured 14 environmental variables, categorized as site-specific or plot-specific. Species richness and abundances were analysed by GLM and GEE; species compositional variance was assessed by NMDS and db-RDA ordinations. Mollusc species richness, ranging between 0 and 15 species per site, and abundance sharply decreased towards high trophy sites, with the chlorophyll-a concentration and water pH highly correlated with species counts. Species compositional variation was driven mainly by water trophy and the quality of organic detritus. Site heterogeneity turned out to significantly control local assemblages of molluscs, while the presence of individual species seemed to be filtered by site trophy and the shoreline length. Thus, to maintain high regional diversity of aquatic molluscs in lowland agricultural landscapes, the presence of low trophy sites seems to be essential.
Abundance-Biomass Comparison (ABC) approach is a graphical approach that compares the abundance and biomass of organisms in order to predict the environmental stress level of an ecosystem. The present study was conducted in selected sites located at non-rehabilitated and rehabilitated areas of the Diyawannawa wetland in Sri Lanka in the monsoonal and non-monsoonal seasons. The ABC was performed on the macrobenthic mollusk species collected from the study sites. Eight species of macrobenthic mollusks, namely, Bithynia tentaculata, Melanoides turbeculata, Melanoides turriculus, Thiara scabra, Lamellidens marginalis, Pila globosa, Gyraulus saigonensis and Lymnaea stagnalis were recorded during the study period. Based on Principal Component Analysis, B. tentaculata, and, P. globosa were identified as characteristic gastropod species that could be used to classify study sites in the rehabilitated and non-rehabilitated areas of this tropical wetland system. In the monsoonal season, overlapping cumulative percentage dominance of abundance and cumulative percentage dominance of biomass curves in sites A, B, and F indicated partially disturbed environmental conditions. The site C of the non-rehabilitated area, showed a typical undisturbed condition and the sites D and E of the rehabilitated area the cumulative percentage dominance of biomass curve was located above the abundance curve, indicating disturbed environmental conditions in these sites during monsoonal season. During the non-monsoonal season in all the sites except site F of the rehabilitated area, the cumulative percentage dominance of abundance curve was located above the biomass curve, indicating undisturbed environmental conditions in these sites. In the site F, the cumulative percentage dominance of abundance and the cumulative percentage dominance of biomass curves were crossing each other, indicating partially disturbed environmental conditions at this site. The values of the W statistic, which ranged from 0.004 to 0.374 in the non-monsoonal season and ranged from 0.1 to 0.2 in the monsoonal season, and pollution and water quality categorization by modified biotic index (MBI) were in agreement with the results of the ABC approach.
The Yangtze River drainage in China is among the most species rich rivers for freshwater mussels (order Unionida) on Earth with at least 68 species known. The freshwater mussels of the Yangtze River face a variety of threats with indications that species are declining in abundance and area of occupancy. This study represents the first analyses of the genetic structure and diversity for the common and widespread freshwater mussel Nodularia douglasiae based on microsatellite DNA genotypes and mitochondrial DNA sequences. Phylogenetic analysis a fragment of the COI mitochondrial gene indicated that N. douglasiae collected from across the middle and lower Yangtze River drainage are monophyletic with N. douglasiae from Japan, Russia, and South Korea. The results of the analysis of both the mtDNA and microsatellite datasets indicated that the seven collection locations of N. douglasiae in the middle and lower Yangtze River drainage showed high genetic diversity, significant genetic differentiation and genetic structure, and stable population dynamics over time. Moreover, we found that the connections among tributaries rivers and lakes in the Yangtze River drainage were important in maintaining gene flow among locations that N. douglasiae inhabits. An understanding of the genetic structure and diversity of a widespread species like N. douglasiae could be used as a surrogate to better understand the populations of other freshwater mussel species that are more rare in the Yangtze River drainage. At the same time, these results could provide a basis for the protection of genetic diversity and management of unionid mussels diversity and other aquatic organisms in the system.
The present study deals with biomonitoring to know mollusc species as an indicator. In the present study, presence, absence and abundance of particular gastropod and bivalve species were identified in the different banks of river Ganga. The study was carried out at two experimental sites, Sodepur (Exp-1) and Khardah (Exp-2), West Bengal, India as the area exhibits a major sewage water outfall in the river compared with upstream control site, Kalyani (Cont-1) and downstream control site, Batanagar (Cont-1). The present biomonitoring shows qualitatively and quantitatively that in experimental no mollusc species were observed near the wastewater discharge area into the bank of river Ganga at Khardah while both sites of the sewage discharge area into the bank of river Ganga at Sodepur particular gastropod Bellamya sp. were observed when compared to control area. The highest variety and total nos of gastropods and bivalves (280 nos) were recorded in the upstream at Kalyani and lowest variety and total nos of only gastropods (150 nos) were recorded in the downstream at Batanagar. The present biomonitoring work was a preliminary observation to know sensitive and tolerant or accumulator mollusc species in the bank of river Ganga from a stretch of Kalyani (upstream) to Batanagar (downstream) in between urban wastewater discharge area (Sodepur and Khardah). Further researches must be relevant in relation to biomarker assessment with the physico-chemical factors and stress tolerant detoxification mechanism of particular mollusc species.
From the main channel of River Ganga 95 invertebrate taxa have been recorded in the endangered Gangetic Dolphin (Platanista gangetica) habitat over an observation period of ten years. Mollusks, Annelids and Arthropods are the dominating benthic groups that constitute the detritivores, filter-feeders and sediment feeders, scrapers/grazers and herbivores. The benthic sediment fauna is rich in diversity and high in abundance. This enables carnivores to occupy a large variety of specialized ecological niches. The qualitative faunal composition of Ganga resembles in general large European rivers with similar representation of taxa. Twelve taxa of marine-originated families were identified, but none of them can be classified as invasive or non-indigenous species. Only two taxa are certainly recognized as non-indigenous neozoans, whereas the remaining fauna shows pristine and stable ecological conditions. In this aspect River Ganga differs from regulated large rivers, where faunal change has largely replaced the original species inventory. Despite the heavy pollution in parts of the river, the original composition of biological diversity is still persisting in the middle reaches of the Ganga. This provides hope for the survival of the Gangetic Dolphin. Introduction The Ganga is the largest river among the rivers originating from the Himalayan region in northern India. The river section in Bihar is one of the few natural and free-flowing large rivers in south Asia.
A comprehensive, but simple-to-use software package for executing a range of standard numerical analysis and operations used in quantitative paleontology has been developed. The program, called PAST (PAleontological STatistics), runs on standard Windows computers and is available free of charge. PAST integrates spreadsheettype data entry with univariate and multivariate statistics, curve fitting, time-series analysis, data plotting, and simple phylogenetic analysis. Many of the functions are specific to paleontology and ecology, and these functions are not found in standard, more extensive, statistical packages. PAST also includes fourteen case studies (data files and exercises) illustrating use of the program for paleontological problems, making it a complete educational package for courses in quantitative methods.
This paper briefly describes the current status of ecology, fisheries and biodiversity of the River Ganges. Apart from being the original abode of the most prized Indian major carps, viz., Catla catla, Labeo rohita, Cirrhinus mrigala and Labeo calbasu, the river sustains fisheries of large catfish, mahseers, hilsa and other miscellaneous fishes. Over the years the fish catch per kilometre stretch in the river has declined significantly and species composition has changed more in favor of non major carp and miscellaneous species. It has also been observed that some exotic fishes have gained a foothold in the ecosystem at favorable stretches, where flows have drastically reduced as a result of abstraction of water from the main river. Changing hydrology, apart from deteriorating environmental conditions, has been to a large extent responsible for change in the fishery scenario in the river. This change has also affected the income levels of riparian fishers. Review of the data generated, over the years, also indicated deteriorating water quality at the stressed sites. The contamination of river water, sediments and fish with heavy metal and pesticide residues is also a factor of concern. With continued stress on the river system an environmental restoration plan was launched by the Indian authorities; its impacts over the years on ecosystem health is also discussed.
Skagerrak populations of Atlantic cod (Gadus morhua L.) have been surveyed at several ¢xed stations since 1919. These coastal populations consist of local stocks with a low age of maturity and a short life span. We investigated 60 time-series of 0-group juveniles (i.e. young of the year) sampled annually from 1945 to 1994. An age-structured model was developed which incorporates asymmetrical interactions between the juvenile cohorts (0-group and 1-group; i.e. one-year-old juveniles) and stochastic reproduction. The model was expressed in delay coordinates in order to estimate model parameters directly from the time-series and thereby test the model predictions. The autocovariance structure of the time-series was consis-tent with the delay coordinates model superimposed upon a long-term trend. The model illustrates how both regulatory (density-dependent) and disruptive (stochastic) forces are crucial in shaping the dynamics of the coastal cod populations. The age-structured life cycle acts to resonance the stochasticity inherent in the recruitment process.
Benthic organisms are generally considered to
be good indicators of environmental conditions
of aquatic ecosystem. The present study was
undertaken to study the diversity and seasonal
variation of macrobenthic invertebrate fauna
in Behlol Nullah, (Jammu) for a period of one
year (May, 2009-April, 2010). The benthic
macroinvertebrate fauna was represented by
sixteen species belonging to three groups viz.
Annelida, Arthropoda and Mollusca. The
relative diversity, species richness, dominance
and evenness were calculated. In addition,
percentage contribution of Annelida,
Arthropoda and Mollusca individuals to total
macrobenthic population was determined.
Water quality was also assessed for the period
of investigation. Tubifex tubifex (Annelida) and
Chironomus chironomus (Diptera) were
observed to be most dominant species, while
the rare species were Branchiura sowerbyii,
Hydrocoptus sps. and Laccophilus parvulus.
Significant changes in macroinvertebrate
assemblages were primarily due to changes in
water quality. Macroinvertebrate fauna proved
to be good indicator of water quality and
thereby help in monitoring the health status of
this lotic system.
Wetlands are rich biological resources and support livelihood and nutritional security to a huge populace globally. In the present study, two ecologically distinct floodplain wetlands viz., Khalsi and Akaipur located in the sub-basin of Jamuna river in lower Gangetic basin, were studied for abundance, species richness and diversity indices of macro-zoobenthic communities across four seasons. The selected wetlands vary in terms of ecological regimes such as, water volume, depth, link channel, agricultural runoffs, macrophyte coverage etc. Khalsi, a seasonally open beel (wetland) that occasionally exchange water with river Jamuna during high flood, while Akaipur is a closed beel with no exchange of water. The studies indicated higher community richness in macrophyte dominated seasonally open Khalsi wetland (22species) as compared to closed Akaipur wetlands (20 species). The community abundance was higher in Khalsi (8496 nos/m 2) as compared to Akaipur. Average Dominance, Simpson and Shannon diversity indices for Khalsi and Akaipur were calculated as 0.3, 0.7 & 1.5 and 0.2, 0.8 & 1.7, respectively. The community structure of wetlands revealed dominance of a single group, gas-tropoda (99%), followed by bivalvia (0.64%), diptera (0.27%) and oligochaeta (0.09%) in Khalsi, whereas, Akaipur depicted community structure with dominance of gastropoda (46.18%) followed by oligochaeta (41.36%), diptera (11.22%) and bivalvia (1.24%). The trophic state index (TSI) based on chlorophyll a (Chla), Secchi disc transparency and total phosphorus showed significant (p < 0.05) variations in both wetlands between different seasons. The water quality parameters were also significantly (p < 0.05) differ in both the wetlands except dissolved oxygen. The CCA components, CCA1 and CCA2 explained 27.59% and 23.95% and 39.78% and 15.26% of the species environment correlation in Akaipur and Khalsi, respectively. The distribution range of macro-zoobenthos varies 0.30-0.92 and 0.26-0.96 in Khalsi and Akaipur, respectively. The study revealed better ecosystem health of Khalsi beel in sustaining aquatic diversity while Akaipur beel is succeeding towards super eutrophic state. Thus, the present study provides baseline information on assemblage patterns and community structure of macro-zoobenthos in two important wetlands for sustainable management of the aquatic bioresources.
In this chapter the effects of macrobenthos on chemical changes in sediments occurring during and after burial (i.e., chemical diagenesis) will be considered. The importance of sediments to the biogeochemical cycling of materials is well known (Mortimer, 1941, 1942, 1971; Lee, 1970). Freshwater sediments act as both a source and a sink for biologically important materials such as phosphorus, carbon, nitrogen, sulfur, and silicon. Furthermore, sediments are known to play an active role in regulating cycles of trace metals, radionuclides, and xenobiotics (Jones and Bowser, 1978). Because of this, knowledge of the chemical diagenesis of sediments is essential to an understanding of materials cycling in freshwater environments.
The sediment reservoir of a lake plays an important role in helping to elucidate the many processes occurring within the total lake system, including its surrounding surface and ground water drainage basins. Of course, lake bottoms have long been recognized as the depositional site of both mineral and organic matter that is transported to the lake from the drainage basin, as well as matter which forms and settles from within the water body proper. However, early studies of lakes tended to treat the sediments as simply a repository having little or no additional reaction with the lake once deposited. The sediments were viewed primarily as a record of the lake history.
Ecologists have fiercely debated for many decades whether populations are self-regulated by density-dependent biological mechanisms or are controlled by exogenous environmental forces. Here, a stochastic mechanistic model is used to show that the interaction of these two forces can explain observed large fluctuations in Dungeness crab (Cancer magister) numbers. Relatively small environmental perturbations interact with realistic nonlinear (density dependent) biological mechanisms, to produce dynamics that are similar to observations. This finding has implications throughout population biology, suggesting both that the study of deterministic density-dependent models is highly problematic and that stochastic models must include biologically relevant nonlinear mechanisms.
Loch Linnhe and Loch Eil form the inner part of an extensive sea-loch system on the west coast of Scotland. Brief descriptions of the topographical and hydrographical characteristics of the area are given together with information on the granulometry and total organic carbon content of the sediments. A detailed quantitative faunal list of the macrobenthic species is given and their distribution over twenty-four stations throughout the system is described. The fauna may be roughly sub-divided into four major groups: 1.1) the deep-mud fauna, approximating to the Amphiura chiajei sub-community of the boreal Amphiura communities,2.2) the sandy-mud fauna, approximating to the Amphiura filiformis sub-community of the boreal Amphiura communities,3.3) the sand fauna, a mixture of species from the boreal Syndosmya and Venus communities,4.4) the gravel and pebble fauna, approximating to the Modiolus epifauna communities.There is considerable intermingling of these groups at many stations and, in addition, a number of ubiquitous species are predominant over a wide range of stations. It is concluded that distinct faunal communities do not exist in the system. Important environmental factors affecting the distribution of species are thought to be sediment-type, bottom current speed and, to a lesser extent, total organic content of the sediment. Depth appears to have little effect on distribution. Possible reasons for the blurring of distinctions between communities in enclosed and inshore areas are discussed.
Ecologists have searched for general principles, or assembly rules, which determine how species combine to form communities. Two major strands of research highlight the interaction of assembly rules operating at different levels of community organisation, and within uncertain local and historical contingencies. Here, we review the literature on community assembly within the context of three principal determinants: dispersal constraints, environmental constraints and internal dynamics. This classification separates external factors (dispersal and environmental constraints) from internal processes (internal dynamics). We assert that assembly rules are general, deterministic and mechanistic, and operate on internal dynamics within the constraints imposed by the local environment and the history of species invasions. Several assembly rules have been proposed to operate within and across trophic levels, as well as on whole systems. The rules act through resource dynamics and spatial dynamics to select species or subsets of species that can coexist, and may lead to patterns of increasing biomass and non-random spatial distributions. Environmental constraints restrict species establishment and mediate interactions among successful colonists; a change in environmental constraints, either exogenous or endogenous, may drive community change. Even in systems at equilibrium, environmental constraints influence the outcome of assembly rules. Dispersal constraints determine the pool of potential colonists available at a particular time and place, and are a complex amalgam of species-specific traits, storage effects, landscape ecology, and history. The order and timing of species invasions (dispersal constraints) interact with assembly rules to produce priority effects. The directionality of community assembly may be lost if either the rate of species invasions or the rate of non-selective species extinctions exceeds the rate at which species are selected by assembly rules. The falling apart, or disassembly, of a community through breakdown of species interactions may follow different rules or a different assembly trajectory.
Benthic community respiration rates of profundal sediments of Fuschlsee (37.6 mg O2 m–2 h–1 — eutrophic), Mondsee (40.19 mg O2 m–2 h–1 — eutrophic) and Attersee (11.5 mg O2 m–2 h–1 — oligo-mesotrophic) were measured in situ, and in cores. By exposing the sediments to different oxygen levels in the laboratory it was found that benthic community metabolism reduced with decreasing oxygen concentrations. The slope of the regression lines, relating oxygen uptake rates to oxygen concentrations, differed significantly for the different sites investigated. These results were closely related to the trophic conditions of the lakes.
One of the most ubiquitous phenomena of all natural populations is their variability in numbers in space and time. However, there are notable differences among populations in the way the population size fluctuates. One of the major challenges in population and community ecology is to explain and understand this variety and to find possible underlying rules that might be modified from case-to-case. Population variability also has a spatial component because fluctuations are often synchronized over relatively large distances. Recently, this has led to growing interest in how ‘internal’ (density-dependent) processes interact with ‘external’ factors such as environmental variability.
Standard methods for the examination of water and wastewater
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- O T Lind
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- J G Needham
Diversity of edible aquatic mollusk and their nutritional contribution in selected Terai districts of Nepal
- S K Wagle
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- A Gautam
Seasonal variations in the macrobenthic fauna of Gadigarh stream (Miran Sahib)
- Sps Dutta
- Y R Malhotra
Macrozoobenthic community as biological indicators of pollution in river Jhelum
- A Syed
- M F Mir
- I Syed
- A M Mir
- I A Ahangar
Frequency, abundance and density of plant species by list count quadrat method
- M Mahajan
- S Fatima