Development of a Periphytic Diatom-Based Comprehensive Diatom Index for Assessing the Trophic Status of Lakes in the Lower Reaches of the Yangtze River, China

Periphytic diatoms play important functional roles in aquatic ecosystems. Their community compositions are widely used in water quality monitoring due to their wide distribution, short reproductive cycles, and sensitivity to environmental changes. In this study, 116 samples of periphytic diatom samples were collected from lakes in the lower reaches of the Yangtze River. The weighted average without tolerance down-weighting regression method was used to develop total phosphorus (r2 = 0.661), total nitrogen (r2 = 0.699), and chemical oxygen demand (r2 = 0.423) models, and the optimal and tolerance values of 78 periphytic species were calculated. Then, a new index, the comprehensive diatom index (CDI), was established on the basis of the optima and tolerances of these 78 species concerning the three environmental variables (TP, TN, and COD) to assess the water trophic status of the lakes in this region. According to the CDI, the trophic statuses of 8, 17, 23, 30, 22, and 14 sample sites were oligotrophic, mesotrophic, light eutrophication, moderate eutrophication, heavy eutrophication, and ultra-eutrophication, respectively. The CDI was more strongly correlated with the conductivity, pH, TP, TN, COD, and TDS than other diatom indices. These results demonstrate that the CDI is a useful metric for assessing the water trophic status of the lakes in the lower reaches of the Yangtze River.

Periphytic diatoms in the presence of a cyanobacterial bloom: A case study of the Vrutci Reservoir in Serbia

Despite their unique ecology and implications for ecological assessment, diatoms in lentic ecosystems are still insufficiently studied in both scientific research and operational monitoring. In particular, the ecology of periphytic diatoms relative to the global expansion of cyanobacterial blooms in lakes has not been described at all. This study aims to describe the diversity and dynamics of a periphytic diatom community in the Vrutci Reservoir during Planktothrix rubescens bloom, and to evaluate the adequacy of standard diatom index implementation in lentic ecosystems relative to the diatom index adapted for lakes ? the Trophic Diatom Index for Lakes (TDIL). The study was conducted in the Vrutci Reservoir in western Serbia. Periphyton was developed on an artificial glass substrate during the summer of 2015, following a depth gradient of a stratified water column. Diatom diversity and abundance, as well as diatom indices were estimated. Discounting the cyanobacterial bloom, 79 taxa of diatoms were recorded and among them the species Aneumastus stroesei as the first representative of the entire genus Aneumastus ever to be detected in Serbia. Diatom distribution along the depth gradient was clearly associated with shifts in environmental conditions. TDIL showed an advantage over standard diatom indices in terms of stability during experimental period and uniformity along the depth gradient, indicating the necessity for further testing of this index performance in lakes, and consequently local water-quality legislation update.

Komposisi Diatom (Bacillariophyceae) Perifitik pada Substrat Kaca di Sungai Kapuas Kecil Kota Pontianak Kalimantan Barat

Periphytic diatom (Bacillariophyceae) is diatom that lives attach on a substrate and it was dependent on the environmental conditions in an aquatic ecosystem. This study was aimed to determine the composition of periphytic diatom (Bacillariphyceae) on glass substrate and the condition of physical chemical water in Kapuas Kecil River. This study was conducted from September to December 2017. The sampling stations were chosen by purposive random sampling method and divided into four stations. At each station in the river were installed 5 baskets each with 5 glass slides. Samples were collected from three baskets with sampling intervals on day 2, 5, 10, 15, and 20. The result shows that the composition of periphytic diatoms (Bacillariophyceae) in Kapuas Kecil River consists of 29 genera from 2 orders (Pennales and Centrales) and 12 families. The most commonly genera found of periphytic diatom were Eunotia, Gomphonema, Frustulia and Nitzschia.

Pengembangan metode bioasesmen untuk penilaian kualitas air Sungai Cihampelas di DAS Citarum

Cihampelas Stream is a tributary of the Citarum that flows across the Regency and Bandung area along 8,5 km. Cihampelas Stream are utilized by the community for domestic activities, tourism, agriculture, and fisheries. This study aims to determine the water quality based on Macrozoobenthos Index of Biotic Integrity and Periphytic Diatom Index of Biotic Integrity and its correlation with the Pollution Index (water classes). This research was conducted at four Cihampelas Stream stations representing the minimal areas of disturbance to the predicted areas of disturbance such as Cilengkrang, Cisurupan, Pasanggrahan, and Mekarmulya. Water sampling, macrozoobenthos, and periphytic diatom was conducted from July to September 2016 four times at two-week intervals. Assessment of water quality using Macrozoobenthos Index of Biotic Integrity shows that Cihampelas Stream is categorized from very good to bad category with index value ranging from 4?18. The water quality of the Cihampelas Stream shows very good to bad category based on the value of the Periphytic Diatom Index of Biotic Integrity which ranges from 3?15. Based on Pollution Index, along Cihampelas Stream is fulfilled class I to exceed class IV of water quality standard. Spearman correlation analysis results shows that Pollution Index (water classes) has negative correlation and stronger to Macrozoobenthos Index of Biotic Integrity compared to Periphytic Diatom Index of Biotic Integrity.Development of bioassessment methode for water quality assessment of Cihampelas Stream in the Citarum River Basin

Influence of tributaries on the periphytic diatom community in a floodplain

In impacted floodplains, small tributaries have an essential role in the maintenance of ecosystem biodiversity. Aim: We aimed to characterise the periphytic diatom community (Bacillariophyta) in a protected area at the Upper Paraná River floodplain considering the importance of tributaries as a source of propagules. The purpose of this study was to understand the influence of the tributaries in the periphytic diatom community (Bacillariophyta) in a protected area at the Upper Paraná River floodplain. We expect that species present in the main river channel (mainly in the last stretch) would be a subset of the community present in the tributaries. Methods The study area is located in the last non-dammed stretch of the Paraná River in this floodplain, with the contribution of several tributaries. Sampling was performed in 2014 in two tributaries and three sites at the Paraná River main channel, and the periphytic material was obtained from petioles of the aquatic macrophyte Eichhornia azurea (Sw.) Kunth. Results We identified 115 diatom taxa. Higher values of species richness were registered in the tributaries, and higher densities in the tributaries and at sampling sites under the direct influence of the tributaries. We also observed a higher similarity between the tributaries, which are located in the preserved side of the floodplain. The results of beta diversity showed that closer sites had lower values, and that the species turnover was the component more important in this floodplain. Conclusion In this way, these results reinforce the importance of tributaries mainly on the algae establishment and development reflected in the density of species. It demonstrates that sites in preserved area present a higher species richness and can serve as a pool of propagules for downstream environments.