Benthic community ecology for Algerian river Seybouse

The Seybouse is the second largest river basin in Algeria, hosting an important biodiversity and providing various ecosystem services. This watershed is highly influenced by agricultural and industrial activities, which threaten its biodiversity and ecosystem integrity. The use of benthic macroinvertebrates as biological indicators has a long tradition in developed countries and integrated into all assessments of the ecological quality of river systems. However, the macroinvertebrates of many North African regions are still not well studied, including those of the Seybouse river. The aim of this study is to assess the inventory and ecological role of benthic macroinvertebrates in inland waters of the Seybouse River and determine the impact of pollution on their spatial distributions. We sampled the benthic macrofauna of Wadi Seybouse and its affluents using regular surveys in three sites, of which one was in the upper Seybouse Bouhamdane in Medjez Amar and two in the middle Seybouse. Between December 2019 and May 2020, 10 physico-chemical parameters (pH, EC, OD, water speed, NO3, Salinity, NO2, MES, turbidity, depth) were measured in order to establish a health state diagnosis of these aquatic ecosystems. The complementary biological approach by the analysis of populations of macroinvertebrates identified 7482 individuals and 40 taxa divided into five classes: Crustaceans which were the most dominant, insects with the main orders (Ephemeroptera, Diptera, Trichoptera, Heteroptera and Odonata), Molluscs, Nematodes and Annelids. The physico-chemical analyzes and the application of the organic pollution indices indicated a strong to excessive pollution for all sites, especially in Seybouse upstream

Community structure of benthic invertebrates in the Allipén River basin, North Patagonia, Araucania region (38º S, Chile)

One of the biological indicators most used to determine the health of a fluvial ecosystem are the benthic macroinvertebrates. The presence of recurrent species in a wide gradient of latitudes, dominates the biogeographic pattern of the benthic macroinvertebrates in Chilean fresh waters, nevertheless the knowledge on the communitarian ecology of these in the Chilean rivers continues to be scarce. Null models became a powerful statistical tool for describing the ecological mechanisms that drive the structure of an ecological community and the underlying patterns of diversity. The objective of this study was to determine the community structure of benthic invertebrates in the Allipén River by describing their composition, richness and abundance of species through richness models and null models based on presence/absence. The results reveal a high family richness and low diversity, three phyla, five classes, 11 orders and 28 families were identified in the study area during the four seasons of the year. The Arthropoda phylum was the most representative in abundance and richness. Regarding to richness, Trichoptera (7 families) and Diptera (6 families) followed by Ephemeroptera (3 families) were the orders that showed the greatest diversity of families, however, a low diversity with a H’≤ 1.5 nit was registered in the study area. We demonstrated through the null models, the randomization in the species associations corresponding to the three analyzed sites. The information provided here contributes to the understanding of the ecological patterns of the invertebrate communities in the Allipén River, establishing the basis for more complex ecological studies.

Diversity of benthic macroinvertebrates and water quality of Karasu Stream (Black Sea)

The study was conducted in Karasu Stream (Sinop Province, Black Sea Region of Turkey). The purpose of this study is, to determine the benthic macroinvertebrate composition of the stream, together with some of its environmental characteristics (water temperature, pH and dissolved oxygen) to evaluate the trophic level of the stream. Samplings of benthic macroinvertebrates and environmental variables were performed monthly at ten stations between February 2013 and January 2014. As a result, 18260 specimens were investigated and 175 taxa were determined. Chironomidae and Oligochaeta were the higher groups in terms of species richness with 48 and 38 taxa, respectively. The BMWP and ASPT indices indicate that all the stations belong to “slightly polluted (Class II)” or “unpolluted (Class I)” water quality levels.

Evaluation of water quality of Çoruh River Basin (Turkey) using some biotic indices

In this study, it was aimed to evaluate the water quality of the Çoruh Basin using BMWP (Biological Monitoring Working Party) index, ASPT (Average Score Per Taxon) index, Shannon-Wiener Diversity Index, EPT (Ephemeroptera Plecoptera Trichoptera taxa), EP (Ephemeroptera Plecoptera taxa) index scores and benthic macroinvertebrates. The benthic macroinvertebrates were collected from 54 stations at the Çoruh basin between 2014-2016 years. Standard hand net (D-frame net) and Ekman-Birge grab were used as sampling tools. As a result of the diagnoses, a total of 7246 individuals belonging to Insecta, Crustacea, Mollusca, Oligochaeta and Plathyhelminthes were obtained. It was determined that the most dominant group was Insecta and the rarest group was Plathyhelminthes. It was observed that the BMWP score ranged between 5 and 94, and the lowest and highest number of families detected in the stations were 1 and 18, respectively. It was determined that the Shannon Wiener diversity index value was between 0.54-2.20, therefore the basin streams generally showed moderate pollution. The results of BMWP index show that the basin streams had mostly show 3rd and 4th class water quality and also biodiversity decreases with the deterioration of the riverbed or exposure to pollution.

Species Sensitivity Distributions of Benthic Macroinvertebrates in Fludioxonil-Spiked Sediment Toxicity Tests

In China, the fungicide fludioxonil, that accumulates and persists in sediments, has a widespread agricultural use to control various fungal diseases. Its residues may cause toxic effects to benthic aquatic fauna, thereby impacting ecosystem service functions of aquatic ecosystems. To assess the potential environmental effects of fludioxonil in the sediment compartment of edge-of-field surface waters, sediment-spiked single-species toxicity tests with benthic macroinvertebrates were performed. In all experiments artificial sediment was used with an organic carbon content of 2.43% on dry weight basis. The single-species tests were conducted with 8 benthic macroinvertebrates covering different taxonomic groups typical for the Yangtze River Delta, China. The 28d-EC10 and 28-LC10 values thus obtained were used to construct species sensitivity distributions (SSDs). In addition, our data were supplemented with similar fludioxonil-spiked sediment toxicity data for benthic invertebrates from the Netherlands. Based on SSDs constructed with 28d-EC10 values of 8 benthic species from our experiments in China, hazardous concentrations to 5% of the species tested (HC5’s) of respectively 0.57 mg fludioxonil/kg dry weight sediment and 5.4 µg fludioxonil/L pore water were obtained. Supplementing our data from China with 8 similar toxicity data for other benthic species from the Netherlands, these HC5 values became respectively 1.2 mg fludioxonil/kg dry weight sediment and 11 µg fludioxonil/L pore water.

Choice of benthic macroinvertebrate-based metrics for assessing water quality in the littoral zone under anthropogenic disturbance in southern Lake Kivu (Central Africa)

Benthic macroinvertebrates are widely used to assess the ecological quality of fresh waters. This is because they are in direct contact with the aquatic environment and respond differently to pollutants and changes in the watershed, which are difficult to assess by toxicological or chemical monitoring alone. this study used benthic macroinvertebrate parameters to assess the quality of the nearshore waters of lake Kivu. Twenty-six metrics covering various aspects of the community were tested using whisker plots to compare their sensitivity in discriminating between reference and disturbed stations. Nine parameters (% EPT taxa, % Diptera taxa, % Chironomid taxa, % Insect taxa; % no Insects taxa, ratio EPT/Chironomid taxa, % moderate tolerant taxa, % very moderate tolerant taxa, Family Biotic Index) were found to be sensitive and were able to discriminate between reference and disturbed stations. All sensitive metrics, with the exception of the percentage of EPT taxa, were positively and/or negatively correlated with the physico-chemical parameters affected by the changes in the littoral zone. The combined values of the three calculated biotic indices (ASPT, BMWP and FBI) showed that the biological water quality varies from moderate to good in the reference stations and from average to poor in the disturbed stations. It is concluded that metrics based on benthic macroinvertebrates are effective for assessing water quality in the littoral zone of Lake Kivu in the context of the lack of historical water quality databases and specific tools for toxicological assessment. It is suggested to compare the performance of this approach with others currently used in bio-indication.

Influence of the Mekin hydroelectric dam on the distribution of benthic macroinvertebrates of the Dja stream: South Cameroon region

This work was conducted with the aim of studying the biodiversity of benthic macroinvertebrates in the Dja River and determining the effect of the Mekin hydroelectric dam on their population in relation to the physico-chemical quality of the water. The study ran from May to October 2020 and samplings were carried out on a monthly basis in four different sampling stations located upstream and downstream of the dam. The physico-chemical analyses were done according to standard methods, while the benthic macrofauna was collected using a turbid net of 400 µm mesh size over a total area of about 6 m2 per station. Physico-chemical analyses revealed a decreasing evolution from upstream to downstream of the dam of nitrogen forms (NO3- (1.67mg/L-0.41mg/L); NH4+ (0.31 mg/L-0.21 mg/L) with p>0.05); Electrical Conductivity (21.45µS/Cm-17.1µS/Cm with p<0.05) and Suspended Solids (11.10mg/L-6.57mg/L with p<0.05); while Dissolved Oxygen (49.82%-78.23% with p<0.05) and velocity (0.04m/s-0.23m/s) increased. Organic Pollution Index revealed that the water was moderately polluted (3-4). In total, 1894 individuals, of which 1044 belonging to 2 phyla, 2 classes, 6 orders, 27 families and 47 genera/species were collected upstream; and 850 belonging to 3 phyla, 4 classes, 8 orders, 28 families and 45 genera/species were collected downstream. Odonata was largely abundant and highly represented Trithemis dorsalis (96.05%); while downstream, Heteroptera was largely abundant and highly represented by Poissonia sp1. (79.78%). These results revealed that restoration of the upstream of the dam impacted by organic pollution and physical degradation of the environment is recommended.