Pollution Indicator Species Research Articles

Threshold Response Identification to Multi-Stressors Using Fish- and Macroinvertebrate-Based Diagnostic Tools in the Large River with Weir-Regulated Flow

Biodiversity response-based diagnostic tools are nonlinear approaches that simultaneously consider complex environmental stressors. Such approaches have been used to quantify biological responses to environmental changes. This study identified the major environmental stressors of community turnover and corresponding thresholds by applying diagnostic tools that use multiple biological assemblages in a large river with artificially controlled flow. Four Gradient Forest models were constructed using the relationships between stream biological assemblage and 66 parameters over 12 years. The multi-stressors that caused community turnover and their thresholds differed depending on the biological assemblage, even under the same environmental conditions. Specifically, they showed that operation of weirs has increased the importance of certain species (e.g., non-native species). In addition, specific-taxon response to multi-stressors analysis identified the ecological or management thresholds of endangered species, Korean endemic species, non-native species, and legal pollution indicator species, which must be managed from a biodiversity perspective. These thresholds are significant as the first reference points presented in similar ecological environments and can be used as guidelines for species over the long term. We propose that ‘true’ threshold identification requires efforts to recognize and improve the limitations of GF techniques confirmed in this study. This may ultimately enable a sustainable aquatic ecosystems maintenance and biodiversity preservation.

Assessment of ecological status of Uppanar and Vellar estuaries through multivariate pollution indices

Multivariate pollution degree indices were utilized to evaluate the environmental condition of the Uppanar and Vellar estuaries. The Trophic Index (TRIX) indicates a state of “moderate eutrophication” with a value of 4.92, while the Trophic State Index (TSI) ranged from 40.3 to 57.2, categorizing the trophic states from “oligotrophic” to “eutrophic”. The Comprehensive Pollution Index (CPI) showed a range of 0.13 to 0.94, classifying pollution levels from “unpolluted” to “slightly polluted”. The study revealed that the Uppanar and Vellar estuaries underwent seasonal variations, transitioning from an oligotrophic state during the post-monsoon and summer periods to a eutrophic state in the pre-monsoon and monsoon seasons. The application of multivariate statistical tools allowed the identification of pollution indicator species to assess the estuarine systems. The insights gained from this study can be valuable for assessing other ecosystems facing similar anthropogenic activities, providing a basis for informed management and conservation strategies.

Water quality parameters and population of aquatic insect larvae in Pardi Lake, Gadchiroli District (M.S.) of India

The present research deals with the study on some physicochemical parameters and the population of aquatic insect and insect larvae of Pardi lake, Gadchiroli which was carried out from February 2016 to January 2017. Total 10 genera of aquatic insect larvae recorded during the present piece of investigation, among which Order Diptera is represented by 07 genera and Coleoptera by 03 genera. The Dipteran species are found to be dominant in the lake. The high density of pollution indicator species like Chironomus, Eristalis and Trichoptera larvae indicates the polluted nature of the lake. Thus, keeping in view the importance of the study, the necessary steps should be taken for the conservation and maintenance of lake.

Unveiling the Diversity of Periphytic Cyanobacteria (Cyanophyceae) from Tropical Mangroves in Penang, Malaysia.

Cyanobacteria are one of the most important groups of photoautotrophic organisms, contributing to carbon and nitrogen fixation in mangroves worldwide. They also play an important role in soil retention and stabilisation and contribute to high plant productivity through their secretion of plant growth-promoting substances. However, their diversity and distribution in Malaysian mangrove ecosystems have yet to be studied in detail, despite Malaysia hosting a significant element of remaining mangroves globally. In a floristic survey conducted in Penang, peninsular Malaysia, 33 morphospecies of periphytic cyanobacteria were identified and described for the first time from a mangrove ecosystem in Malaysia. Sixteen genera, comprising Aphanocapsa, Chroococcus, Chroococcidiopsis, Cyanobacterium, Desmonostoc, Geitlerinema, Leptolyngbya, Lyngbya, Microcystis, Myxosarcina, Oscillatoria, Phormidium, Pseudanabaena, Spirulina, Trichocoleus and Xenococcus, were obtained from field material growing on diverse natural and artificial substrata. Oscillatoriales was the dominant order with Phormidium the dominant genus at nine of the 15 sampling sites examined. Three of the morphospecies, Aphanocapsa cf. concharum, Xenococcus cf. pallidus and Oscillatoria pseudocurviceps, are rare and poorly known morphospecies worldwide. Chroococcus minutus, Phormidium uncinatum, P. amphigranulata, and some species of Oscillatoriales are considered as pollution indicator species. This study provides important baseline information for further investigation of the cyanobacterial microflora present in other mangrove areas around Malaysia. A complete checklist will enhance understanding of their ecological role and the potential for benefits arising from useful secondary metabolites or threats via toxin production to the ecosystem.

Mercury at the top of the world: A 31-year record of mercury in Arctic char in the largest High Arctic lake, linked to atmospheric mercury concentrations and climate oscillations

Lake Hazen, the largest lake north of the Arctic circle, is being impacted by mercury (Hg) pollution and climate change. The lake is inhabited by two morphotypes of land-locked Arctic char (Salvelinus alpinus), a sensitive indicator species for pollution and climatic impacts. The objectives of this study were to describe the trends in Hg concentration over time and to determine the relationship of climate to length-at-age and Hg concentrations in each char morphotype, as well as the relationship to atmospheric Hg measurements at a nearby monitoring station. Results for Hg in char muscle were available from 20 sampling years over the period 1990 to 2021. We found significant declines in Hg concentrations for both morphotypes during the 31-year study period. Increased rain and earlier freeze-up of lake ice during the summer growing season was linked to increased length-at-age in both char morphotypes. For the large morphotype, higher total gaseous Hg in the fall and winter seasons was related to higher concentrations of Hg in char, while increased glacial runoff was related to decreases in char Hg. For the small morphotype char, increased snow and snow accumulation in the fall season were linked to declines in char Hg concentration. The Atlantic Multidecadal Oscillation and Arctic Oscillation were positively related to the large char Hg trend and Arctic Oscillation was positively related to the small char Hg trend. Significant trend relationships between atmospheric Hg and Hg in biota in remote regions are rare and uniquely valuable for evaluation of the effectiveness of the Minamata Convention and related monitoring efforts.

Epiphytic algae communities and their relationship with environmental factors in the “One River and Two Streams” Basin in Xizang

Due to the uniqueness of natural environment and ecosystem on the Qinghai-Tibet Plateau, the plateau algal community structure and its relationship with environmental factors have received unprecedented attention. In order to explore the epiphytic algae communities and their relationship with environmental factors in the “One River and Two Streams” Basin in Xizang, a total of 7 sampling sites were investigated in four quarters. Water quality evaluation of the study area was based on both hydrochemistry and epiphytic algae. The results showed that a total of 97 species from 60 genera belonging to five phyla were detected. The community was dominated by Bacillariophyta (48 species from 25 genera), Chlorophyta (17 species from 13 genera), and Cyanophyta (26 species from 18 genera), with average annual relative abundances of 88.5%, 6.7%, and 3.6%, respectively. Nitzschia sp. of Bacillariophyta was the dominant species. Significantly higher water temperature (WT) but lower pH was seen in summer than in other seasons. Water turbidity in autumn and ammonia nitrogen (NH3-N) concentration in winter were significantly higher than in other seasons. Total phosphorus (TP) did not change much across seasons. A water quality evaluation based on both hydrochemical parameters (single-factor analysis and comprehensive pollution index, CPI) and the biological index of epiphytic algae (diversity index, pollution indicator species, and index of biotic integrity, IBI) indicated that water quality was mostly at good or medium status. Redundancy analysis (RDA) indicated that the measured environmental factors had no significant effect on the relative abundance and the dominance of pollution indicator species. Dominant species were positively correlated with photosynthetically active radiation (PAR) and ultraviolet A (UVA), and turbidity had a significant negative effect on the number of species. By combining a hydrochemical and biological index, this study emphasizes the importance of water quality monitoring from both a short-term transient as well as a long-term comprehensive perspective. This approach can provide comprehensive and systematic reflections on the health status of waterbodies.

Concentration of fifty-six elements in excreta of penguins from the Antarctic Peninsula area

Seabird feces as indicators of the exposure to environmental contaminants have been studied worldwide. Penguins are indicator species for marine pollution, but their role as biovectors of rare earth elements (REEs) to ecosystems have been little studied. The present study quantified the concentration of REEs and trace elements (TEs) in feces of gentoo penguin (Pygoscelis papua). Adult penguin excreta from Fildes Bay (King George Island) and Yelcho Base (Palmer Archipelago) were collected and then analyzed by ICP-MS. Among REEs, levels ranged from 0.0038 to 1.02 μg g−1 d.w. for Lu and Ce, respectively. For TEs, the levels varied widely through the sample set, with Al, Fe, Sr, Zn and Ti as the highest mean levels, particularly at Fildes Bay. The data show that gentoo penguins act as a biovector organism by transporting TEs and REEs from the sea to land via excreta, reaffirming that this species acts as an important biovector organism in Antarctic ecosystems. The potential impacts of this process on Antarctic ecosystems needs further research.

Сезонна динаміка альгофлори озера Засвітське (Рівненська обл., Україна)

The study deals with the algal flora of Lake Zasvitske (Rivne region, Ukraine). They belong to 8 divisions, 13 classes, 24 orders, 34 families and 51 genera. Totally 61 species of algae (62 intraspecies taxa) were identifiedhe. It was shown that Bacillariophyta, Chlorophyta, Cyanobacteria and Streptophyta play the significant role in lake phytoplankton development. According to the population Shannon diversity index varies from 2.13 bit/spec. (October) to 3.89 bit/spec. (July), and according to biomass this index varies from 1.63 bit/spec. (June) tо 4.10 bit/spec. (July). In the lake phytoplankton poly-dominant structure prevails. In Lake Zasvitske the phytoplankton core is developed with planktonic-benthic and planktonic species, slow-flowing species according to water saturation with oxygen and rheophilicity, indifferent species in relation to the density, pH level of the environment and water temperature, mesoeutrophic ones and species with wide amplitude according to the trophic level. Eurysaprobes (according to the Watanabe system) and beta-mesosaprobionts (according to the Pantle-Buk system as modified by Sladechek are predominant among indicator species of organic water pollution.

Influence of the urban environment on four mushroom species in the light of their elemental composition

The mushrooms are living organisms with excellent capability to adapt to the multiple challenges of their environment. Several species are well represented in urban green areas (parks, green spots, and recreation grounds). We investigated the influence of the urban environment over two saprotrophic (Bovista plumbea, Lycoperdon perlatum) and two mycorrhizal (Amanita rubescens, Suillus granulatus) species commonly present in urban parks of Cluj-Napoca, a major city of Romania. Three control sites close to the city were chosen. We determined 19 elements (Ag, Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, S, Si, Sr, Ti, and Zn) in the fruiting bodies of mushrooms and in soils by ICP OES technique. S. granulatus was the most sensible species to the urban pollution; this species accumulated 130 and 4.40 mg kg−1 (dry weight) median concentrations of Al and Ni, respectively. The highest concentration of Ag, Cu and Fe was determined in B. plumbea (3.18, 83.7 and 141 mg kg−1, respectively) and L. perlatum (4.68, 91.0 and 125 kg−1, respectively) collected from the city. The saprotrophic species contained appreciably higher concentrations of Ag, Cu, Fe, Mg, P, and S than the mycorrhizal ones. Common feature of all four species was the higher Ag and Sr concentrations in the fruiting bodies of urban origin. Our results suggest that the unique defence mechanisms of the species might have higher impact over the elemental profile of the mushrooms than the soil properties. We propose L. perlatum and S. granulatus as suitable indicator species of the urban pollution with regard to inorganic pollutants.

Influence of water quality and sediment nature on macrobenthic community structure along Paradeep, an industrial and port influenced tropical coastal stretch of North East coast of India, Bay of Bengal

Macrobenthic community plays a major link between primary producers, decomposers and higher trophic levels in the marine environment. To assess these ecologically important groups, water and sediment samples were collected from 17 GPS fixed locations along a stretch of 42 km on the north east coast of India during the period 2017–2019. Faunal assemblage comprises of total 12 groups; belonging to 4 phyla (Annelida, Arthropoda, Mollusca and Echinodermata) and one minor phylum (Brachiopoda), represented by 25 families. Mean abundance varies from 80 to 2640 ind. m−2 and out of these more than 90% of the population is contributed by 7 groups namely Polychaeta (37.88%), Gastropoda (20.75%), Scaphopoda (9.82%), Bivalvia (9.41%), Amphipoda (9.26%), Sipuncula (2.72%) and Isopoda (2.45%). Seasonally abundance was highest in pre monsoon (1162 ind. m−2) and lowest in monsoon (682 ind. m−2). The similarity and group average clustering (Bray Curtis) of macrobenthic community divided the area into 2 major groups (50% similarity), Group-I with stations of estuary and port and Group-II is the shoreline locations. The SIMPROF test used for further division of the stations revealed that the regions could be subdivided into four groups namely estuary, port, outfall and shoreline. Occurrence of the pollution indicator species such as Capitella capitata, Paraprionospio pinnata, Cossura longocirrata and Cossura coasta in the estuarine and port area. A positive correlation (P ≤ 0.01) between sand vs macrobenthic abundance and negative correlation between silt vs macrobenthic abundance (P≤0.01) and organic matter vs macrobenthic abundance (P ≤ 0.01) was observed as the loose texture of sediment provides higher interstitial space to harbour more number of benthos. Salinity varied in wide range from 1.10 to 30.02 PSU as, the study area include different environment such as estuary, port, outfall and open sea and besides this, river Mahanadi which discharge large quantity of fresh water during monsoon season.

Diversity of euglenoids in a drinking water source in Burkina Faso (West Africa): implications for sustainability and water quality

Euglenophyta are a group of algae that occur in water polluted by organic matter, which makes them a good indicator for organic pollution. This study aimed to determine the diversity of Euglenophyta, the environmental conditions favourable to their development and their implication in the sustainability and quality of the water in Loumbila reservoir. Algal and chemical water samples were collected monthly between January 2015 and June 2015. Phytoplankton species were identified under a light microscope using a Fuchs-Rosenthal chamber for algal cell counting. In total, 34 species of Euglenophyta were identified, four of which are new to the algal flora of Burkina Faso. The abundance and number of species of the genera Euglena and Phacus were significantly (p < 0.05) higher in the dry season. Euglena deses, Euglena texta, Euglena caudata, Phacus lefevrei, Phacus ranula and Phacus orbicularis were identified as indicator species of high nutrient concentration. The abundance of these genera was positively correlated with pH, dissolved oxygen, water transparency, conductivity, nitrates and orthophosphates. This study on the diversity of Euglenophyta enabled us to identify indicator species of reservoir pollution and the environmental factors favourable to their development. This can be used to guide the future water quality monitoring and management of the reservoir.

Limnological properties and phytoplankton as indicator of pollution, Choba segment, New Calabar River, Port Harcourt Nigeria

The limnological properties and phytoplankton as pollution indicator was studied for three Months between February and April,2022. Water and phytoplankton samples were collected from three stations following standard method of APHA using 45µm mesh size plankton net and plastic bottles for phytoplankton and physicochemical variables respectively. The results showed that some of the physicochemical variables studied had their mean values, pH (6.23±0.69), dissolved oxygen (DO)(5.60±0.11 mg/l), electrical conductivity (EC)(280.00±7.0 µs/cm), sulphate (SO4) (83.00±1.00 mg/l) and turbidity(4.91±0.43 cm) within the permissible limits of WHO while others were above the limits. The results also showed that all the variables did not show significant difference spatially at p&lt;0.05 except BOD, EC and NO3. Most of the variables recorded the highest values in March except NO3 with SO4 and NO3 recording the highest values in station 2. A total number of 31 species of phytoplankton belonging to the five taxonomic groups in the order, bacillariophyceae, cholorophyceae, cyanophyceae, chrysophyceae and xanthophyceae were identified. Phytoplankton species identified to be pollution indicator species were Navicular sigma, Cyclotella combata, Cyclotella operculata, Spirogyra sp, Anabaena affinis, Anabaena flus-aqua, Microcystis pulvenca, and Oscillaria lacustris. The total abundance of phytoplankton was highest in station 2 (1,508 Ind/ml) but lowest in station 1(1,144 Ind/ml). Considering the values of some of the physicochemical variables which were above the permissible limits of WHO and the occurrence of some pollution indicator species, Choba segment of the New Calabar River is considered to be at the verge of been threatened/polluted. Therefore, adequate measures should be put in place to regulate the anthropogenic activities in the area.

Seasonal Dynamics of Algal Flora of Lake Zasvitske (Rivne Region, Ukraine)

This study considers the algal flora of Lake Zasvitske (Rivne region, Ukraine). The author identifies 61 species of algae presented with 62 intraspecific taxa subdivided into nomenclatural types that belong to 8 divisions, 13 classes, 24 orders, 34 families and 51 genera. The paper demonstrates that &lt;i&gt;Bacillariophyta, Chlorophyta, Cyanobacteria&lt;/i&gt; and &lt;i&gt;Streptophyta &lt;/i&gt;play a significant role in lake phytoplankton development. According to the population, the Shannon diversity index varies from 2.13 bit/spec. (October) to 3.89 bit/spec. (July), and according to biomass this index varies from 1.63 bit/spec. (June) to 4.10 bit/spec. (July). In the lake phytoplankton, polydominant structure prevails. In Lake Zasvitske the phytoplankton core is developed with planktonic-benthic and planktonic species, slow-flowing species according to water saturation with oxygen and rheophilicity, indifferent species in relation to the density, pH level of the environment and water temperature, mesoeutrophic ones and species with wide amplitude according to the trophic level. Eurysaprobes (according to the Watanabe system) and beta-mesosaprobionts (according to the Pantle-Buk system as modified by Sladecek) are predominant among indicator species of organic water pollution.

Influence of mattresses washing on the water quality and phytoplankton diversity in selected industrial outlets of Tamil Nadu

The impact of anthropogenic activity of mattresses washing on the quality of two lotic water bodies of Cuddalore SIPCOT industries outlet water bodies two different stations were analysed. The industrial waste water currents battered along the Freshwater ecosystem near SIPCOT industries. Hence an attempt was made to record outlet water bodies two different stations were analysed. The water samples were collected during summer (April-June, 2021) and winter seasons (Oct-Dec 2021) and analysed for various physicochemical parameters. Decrease in dissolved oxygen concentrations along with tremendous increase in electrical conductivity in both the water bodies, was observed due to mattresses washing by using detergents. Heavy metals like lead, cadmium and nickel were absent throughout. The values of iron was increased while manganese was traced out after this activity. This proved that water quality was found to be hampered in both the stations. A total of 65 species of phytoplankton belonging to different taxonimic groups were identified. Among these, 25 species belong to Bacillariophyceae, 20 species to Chlorophyceae, 15 species to Cyanophyceae and 5 species to Euglenophyceae. The numerical superiority of phytoplankton reveals that Nitzschia sps. (6.66 x 103 units/1) is dominant in SIPCOT industries water outlet. The maximum value of Simpson index (SR) or species richness (0.55) was recorded in Cuddalore SIPCOT industry. The high value of species evenness index (J) was also recorded (0.69) in Cuddalore SIPCOT industry. The maximum value of Shannon’s overall index (H¢) of species diversity (1.38) was recorded in industrial outlet. Microcystis aeruginosa, Anabaena, Oscillatoria, Merismopedia, Aphanizomenon, Chlorella, Cosmarium, Scenedesmus, Closteridium, Navicula and Nitzschia were observed in two stations. These are pollution indicator species used for monitoring the environment.

Composition, distribution, and diversity of macrophytes and benthic macroinvertebrate communities in Eleyele Lake, southwestern Nigeria

Many human activities that have an effect on water quality and aquatic health are increasing along Eleyele Lake, which is a vital resource for domestic water supply and fishery in Ibadan, southwest Nigeria. This study provides information on the composition of macrophytes and benthic macroinvertebrates (which are bioindicators) in association with physicochemical parameters in Eleyele Lake. Water, macrophytes, and benthic macroinvertebrates were collected from four stations monthly from March to August 2021 and analysed using standard methods. The relationship between the measured physicochemical variables, macrophytes, and the abundance of benthic macroinvertebrate was explored using canonical correspondence analysis (CCA). The encountered macrophytes represented 19 species (11 emergent, six floating and two submerged) in 16 genera and 12 families. The most abundant species was Ipomea aquatica (25.83%) in station 2 and Sacciolepsis africana (19.19%) in station 1. A total of 282 benthic macroinvertebrate individuals belonging to three phyla, four classes, 11 genera, and 11 species were encountered. Pollution indicator species including Melanoides tuberculata, Biomphalaria pfeifferi and Chironomus larvae observed in all the sampling stations were the dominant species. The CCA indicated that the abundance of macrophytes correlated with depth and nutrient factors (mostly phosphate). The result of the CCA showed the abundance of Chironomus larvae being patterned by dissolved oxygen and nutrient factors (phosphate, nitrate, and sulphate). These further confirmed the polluted status of Eleyele Lake, especially by nutrient enrichment. The dominant macrophytes and benthic macroinvertebrates in Eleyele Lake are pollution-tolerant species and the lake has been impacted by nutrient enrichment.

IMPACTS OF CLIMATE CHANGE ON PHYTOPLANKTON COMPOSITION AND VARIABILITY IN IKO RIVER, COASTAL WATER OF EASTERN OBOLO, NIGERIA

This study investigated the effects of climate change on phytoplankton composition and diversity in Iko River, coastal water of Eastern Obolo, Akwa Ibom State, South Eastern Nigeria. The study area was greatly influenced by tidal flush from the Atlantic Ocean. Phytoplankton samples were collected monthly from October 2021 to March 2022 at high tide and low tide from 3 stations. Phytoplankton was identified and diversity was calculated using standard indices. Dissolved oxygen (3.3–6.0 mg/L) was above WHO guidelines of &lt;5.0mg/L and BOD (2.40-5.30 mg/L) in this study was above the (4.0 mg/L) limit recommended as suitable for aquatic life by the National Environmental Standards and Regulation Enforcement Agency (NESREA), which could pose a threat to aquatic life. A total number of 65 species of phytoplankton were identified in the study area. Bacillariophyta was the dominant group (69%) throughout the study in species number, occurrence and abundance. The increasing order of dominance values was; Bacillariophyta &gt; Cyanophyta &gt; Chlorophyta &gt; Dinophyta &gt; Euglenophyta . Diversity indices (Margalef, Shanon, Dominance, Simpson Evenness and Equitability) showed spatial variations significant at (P&gt;0.05). Pollution-indicator species such as; Tabellaria fenestrata, Nitzschia. paradoxa, N. filiformis, N. longissima, Cymbella cuspidata, Melosira distans and Anabaena constrica were recorded at either high tide, low tide or at both tides. Concerted efforts have been recommended to Government agencies and individuals to help reduce natural and anthropogenic pollution of the coastal water bodies.

Diversity and ecology of freshwater diatoms as pollution indicators from the freshwater Ponds of Kanyakumari district, Tamilnadu

The present study explores the diversity and ecology of freshwater diatom in the Kanyakumari district, Tamilnadu. Six freshwater ponds namely, Thuckalay pond, Eraniel pond, Pampanvilai pond, Villukuri pond, Erachakulam and Thottiyodu pond were selected from Kalkulam Taluk in Kanyakumari district. A total of 27 taxa of 17 genera were recorded from these freshwater ponds. Among the freshwater diatom species, Gomphonema montanum was found to be the predominant species in all stations except St- 2. The correlation analysis between diatom density and physico-chemical parameters revealed a significant positive correlation of diatoms (Nitzschia sp., Navicula sp., Cyclotella meneghiniana and Stauroneis sp) with nitrate, phosphate and lead at sampling statins St- 2 and 6. CCA analysis revealed that the concentration of calcium, chloride, pH, alkalinity, silica, and ammonia were found to favor the occurrence of dominant species such as Cymbella turgiduta, Gomphonema sp., Rhopalodia sp., in St-3 and St-4. Among all ponds, certain parameters like total alkalinity, nitrite, phosphate, sodium, cobalt, potassium perhaps reflect the influence of agricultural waste, sewage waste, or anthropogenic activities. The statistical indices in coherence with the dominance of pollution indicator species such as Nitzschia palea, Melosira granulata and Cyclotella meneghiniana revealed that the stations St-2, 4 and 6 were heavily polluted, whereas St- 1, 3 and 5 were less polluted.

Makrozoobenthos As A Bioindicator Of Water Quality In The Masang Kecil River In West Pasaman Regency

Sungai Masang Kecil is located in the middle of the PT Andalas Agro Industri (PT AAI) palm oil plantation and mill. This activity will have an impact on aquatic biota, especially benthos. Benthos occupies an important position in the food chain and lives permanently on the substrate to be used as a bioindicator of pollution. This study aimed to determine the Community Structure of Macrozoobenthos and the indicator species of water pollution in the Masang Kecil River around the PT AAI area, West Pasaman Regency. This research was conducted using a purposive sampling method with three sampling points, namely upstream and two downstream points after the Wastewater Treatment Plant (IPAL) and after the confluence of tributaries. Sampling using Surber net size 30 x 30 cm. The results of identifying the types of Bento's organisms as a whole identified as many as 45 species. Most species are found in Class Insecta. Based on the diversity index, the water quality in PT AAI's river basin was classified as unpolluted, and it could be concluded that the benthic condition was in good condition on a scale of 4. In the current study, the Diptera order as an indicator of polluted water was most commonly found among orders from other insect classes, namely, ten species. However, there were nine species from the Order Ephemeroptera as an indicator of clean waters and six species for Trichoptera.

Macrobenthic Assemblages, Distribution and Functional Guilds from a Freshwater-Dominated Tropical Estuary

Assessment of benthic diversity and estuarine ecological quality is becoming increasingly important. Estuaries are not only highly productive and variable environments, but they are also areas of high anthropogenic perturbations. In this study, benthic macrofauna were sorted, identified and analyzed from a freshwater-dominated tropical estuary along the Bay of Bengal to assess their community structure, distribution and functional guilds, and to uncover the environmental drivers influencing their distributional patterns. Results revealed that the studied physio-chemical variables (DO, pH, alkalinity and temperature) were significantly varied (p &lt; 0.05) among the sites. Capitella sp. was dominant (18%) of the forty morphospecies recorded, indicating organic richness of the area. The ANOVA results revealed that macrobenthic density differed significantly (p &lt; 0.01) between the study locations, and diversity indices (Shannon diversity index, H′) also differed significantly (F4,12 = 5.89; p = 0.02). The benthic density decreased from the head to the mouth, which could be related to salinity fluctuations and large freshwater discharges. Upstream sites were completely segregated from downstream and mid-estuarine sites, according to cluster analysis (CA). The SIMPER results clarified the site grouping pattern, showing that Mysis-1 spp., Capitella spp. and Nephtys-1 were the most significant contributors. From the communities, five functional trophic groups were identified where deposit feeders were the most dominant (66.44%). Most of the macrobenthos had strong positive correlations with DO (r = 0.92) and water temperature (r = 0.86) and a negative correlation with soil pH (r = −0.28), per correlation and CCA analyses. Individually, soil pH (r = 0.88) and alkalinity (r = 0.898) showed strong positive correlation with Capitella sp. and Chironomus sp.2. The above results indicate that macrobenthos of this estuary do not follow the usual pattern of spatial distribution, and they are structured by DO, alkalinity and soil pH. In addition, dominance of some pollution indicator species (Capitella sp. and Chironomus sp.) and deposit feeders indicates a poor ecological condition of the estuary.

Phytoplankton flora of asejire reservoir, Southwest Nigeria

An appraisal of the current ecological status of Asejire Reservoir was carried out using the reservoir phytoplankton composition and community structure. Monthly sampling was carried out in nine selected sites for twelve months. Data were analysed using descriptive statistics, analysis of variance, Shannon-Weiner and Evenness indices. One hundred and fifty-four phytoplankton taxa were identified. Taxa dominance was in the following order: Bacillariophycea>Chlorophycea>Charophycea>Cyanophycea>Euglenophycea>Ochrophycea>Dinophyceaa. Microcystis sp. were the most abundant species followed by Anabaena sp. and Closterium sp. The riverine zone accounted for 50.8% of the total phytoplankton population. One-way analysis of variance between the zones indicated that there was a significant difference (F=11.41, df=2, p=0.0000146) in the spatial distribution among the stations. Most of the recorded phytoplankton species are cosmopolitan with the presence of the following species: Staurastrum, Closterium, Cosmarium, Anabaena, and Oscillatoria. The presence of some pollution indicator species is a cause of concern and the need to ensure holistic and effective monitoring measure is put in place to safeguard the reservoir.