Paringin District is one of the coal mining areas in South Kalimantan with the exploitation method of open pit mining. This activity opens rock layers containing sulfur, reacting with water and oxygen, spreading sulfide acid into the environment. Analysis of the water quality of the Post-mining Lake in Paringin District is needed based on the biological parameters. The objective aims to analyze the water quality of the Post-mining Lake, Paringin District, based on plankton’s abundance, diversity, and dominance. This research was located in Post-mining Lake, PT. Adaro Indonesia. Data were taken at three sampling points in the pit pond and three depths. Data was taken from 2019 to 2021 using plankton net and analyzed using the enumeration method. The data was processed using the diversity index, dominance index, and saprobic index. Phytoplankton and Zooplankton abundance were dependent on three different depths (p-value>0.05). The most abundant phytoplankton species in all stations was Oscillatoria sp. (>90%) while Nauplius sp. (>30%) for zooplankton. Rainfall in the study area affected the number of individual species very weakly. The highest dominance value of phytoplankton and zooplankton was recorded around the end of 2019 to early 2020 as well as a saprobic index and diversity. Crustacea class considerably exists in all sites, which is Nauplius sp. and Daphnia sp. This situation proved there was a recovery of the plankton population in the lake, no algae blooming and a balance between nutrients and plankton population. In fact, the aquatic habitats are ready to accommodate large ecosystems.

Within the comprehensive hydrobiological investigation of Grosnica water reservoir (Serbia, Yugoslavia) composition and dynamics of bacterioplankton, phytoplankton and zooplankton, as well as their seasonal successions were studied. The composition of plankton communities varies during the vegetation period in the function of the physicochemical features. Grosnica water reservoir with its microbial features belongs to the 1st-2nd class of bonity according to Kohl. The highest values pf bacterio- and zooplankton were recorded in August, while bruto primary production in September.

Primary production of phytoplankton and diversity and biomass of zooplankton of the Sava reservoir (artificial lake), Serbia (Yugoslavia), was studied during the summer and autumn in 1996. The study results were compared with the research results by Perisic et al. (1984) obtained before the dredging of the lake bottom, when bottom sediments with macrophytes were removed. It was found that the water quality was improved in comparison with previous period.

The river Timok with its watershed area is one of very imperilled running water on the territory of Serbia (Yugoslavia). By several years investigations of colonies bottoms (phytobenthos, microzoobenthos and macrozoobenthos) and plankton we have found the following: great diversity and specific phytobenthos and bottom fauna (frequency of certain taxa is considerably larger in relation to the other areas, and new taxa have been recorded). Stated specific structure of phytobenthos and bottom fauna have considerably reflected to right estimation of water quality of tested area.

During one-year examination of the Vlasina river and its main tributaries, the Luznica and Gradska rivers, Serbia (Yugoslavia), in May 1996, the samples were taken for biological and chemical analysis of the watercourse in the spring aspect. Sampling was performed on the five localities of the Vlasina river, and two tribute localities near the mouth thus including all critical points where the changes of physico-chemical water parameters and qualitative/quantitative biocenoses compositions due to the increasing anthropogenic influence could occur. Data on phytoplankton, zooplankton, periphyton and benthos were analysed together with the physico-chemical water parameters in order to determine communities composition and structure and bioindicator species. Based on these results the status of aquatic environment i.e. water quality, was evaluated.

The investigations of qualitative and quantitative composition of plankton and the bottom fauna of the Tisza river, Serbia (Yugoslavia), were conducted during 1998. According to the analyses of the indicator species of hydrobionts, saprobic index was calculated, and the estimation of the water quality of the lower flow of the dam near Novi Becej on the structure and abundance of the investigated organisms.

Riverine carbon (C) composition and export are closely related to changes in the coastal environment and climate. Excessive C inputs from rivers to seas and their subsequent decomposition could result in harmful algal blooms and ecosystem degradation in the coastal sea. In this study, we explored the C transportation and composition in the 24 major rivers of the Bohai Sea (BS) Rim based on the investigation of dissolved organic carbon (DOC), carbon stable isotopes (δ¹³CDOC) and chromophoric dissolved organic matter (CDOM). The results showed that the riverine DOC concentrations were high (10.6 ± 6.04 mg/L) in the BS Rim compared with the DOC levels in the main rivers in Eastern China (4.98 ± 2.45 mg/L). The δ¹³CDOC ranged from −28.29‰ to −25.32‰ in the rivers of the BS Rim, suggesting that the DOC mainly originated from riverine plankton, soil organic matter mainly induced by C3 plants, and sewage. The excitation-emission matrix fluorescence spectroscopy of the CDOM indicated that a soluble, microbial by product-like material accounted for the largest proportion (approximately 40%) of CDOM in these rivers and that CDOM mainly originated from autochthonous riverine sources with high protein-like components. The rivers in the BS Rim transported approximately 0.55 Tg C of DOC to the BS each year, with more than 70% of reactive C based on the CDOM composition. The DOC yields in terms of unit drainage area transported from the small rivers to the BS were higher compared to those of the larger rivers in the world, which indicated that the small rivers in the Bohai Rim could be an important source of the C in the BS. This study would enrich our understanding of environmental evolution in coastal areas with numerous small rivers.

Harmful algal blooms (HABs) are recurrent in the NW Patagonia fjords system and their frequency has increased over the last few decades. Outbreaks of HAB species such as Alexandrium catenella, a causal agent of paralytic shellfish poisoning, and Protoceratium reticulatum, a yessotoxins producer, have raised considerable concern due to their adverse socioeconomic consequences. Monitoring programs have mainly focused on their planktonic stages, but since these species produce benthic resting cysts, the factors influencing cyst distributions are increasingly gaining recognition as potentially important to HAB recurrence in some regions. Still, a holistic understanding of the physico-chemical conditions influencing cyst distribution in this region is lacking, especially as it relates to seasonal changes in drivers of cyst distributions, as the characteristics that favor cyst preservation in the sediment may change through the seasons. In this study, we analyzed the physico–chemical properties of the sediment (temperature, pH, redox potential) and measured the bottom dissolved oxygen levels in a “hotspot” area of southern Chile, sampling during the spring and summer as well as the fall and winter, to determine the role these factors may play as modulators of dinoflagellate cyst distribution, and specifically for the cysts of A. catenella and P. reticulatum. A permutational analysis of variance (PERMANOVA) showed the significant effect of sediment redox conditions in explaining the differences in the cyst assemblages between spring-summer and fall-winter periods (seasonality). In a generalized linear model (GLM), sediment redox potential and pH were associated with the highest abundances of A. catenella resting cysts in the spring-summer, however it was sediment temperature that most explained the distribution of A. catenella in the fall-winter. For P. reticulatum, only spring-summer sediment redox potential and temperature explained the variation in cyst abundances. The implications of environmental (physico-chemical) seasonality for the resting cysts dynamics of both species are discussed.

Aquatic particles and organic carbon (OC) regulate the occurrence and transport of hydrophobic organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) in water-suspended particle-sediment interfaces. Conventional studies on the mechanisms regulating the relationships between PAHs and total particles/OC have ignored micro-scale regulatory factors such as particle size and OC composition. Field research in the eutrophic shallow Lake Taihu, China, revealed that the fine particle fractions 2.7–10 μm in diameter had stronger PAH adsorption capacity and significantly regulated PAH particle size distribution and water-particle partitioning. Selective PAH biodegradation by planktonic microorganisms probably significantly weakened the capacity of the coarse fractions to regulate PAHs. OC fragments at different temperature gradients had markedly different influences on the particle size distribution of PAHs. High-temperature pyrogenic OC fractions (part of black carbon) were the principal OC regulatory factors for medium-to high-molecular-weight PAHs. However, the OC fragments did not directly affect the particle distribution of low-molecular-weight PAHs. During particle deposition and burial, microbial PAH utilization and efficiency probably regulated the burial potential of various hydrophobic PAH species. Biodegradation of relatively less hydrophobic PAHs with octanol-water partition coefficients (log Kₒw) < 5.8 showed an increasing trend with decreasing PAH hydrophobicity. Biological pump action of the relatively higher hydrophobic PAH species (log Kₒw > 5.8) showed a decreasing trend with increasing PAH hydrophobicity. The discoveries of the present work further clarified the mechanisms of PAH partitioning and burial in a eutrophic shallow lake and collectively provides a valuable reference for modeling the transport and dispersal mechanisms of hydrophobic, particle-bound organic contaminants in other aquatic ecosystems.