Search Results (74)

To accurately manage precise feeding and water quality regulation in the rice–duck–crayfish integrated system (RDCI), the continuous monitoring of plankton and physicochemical parameters in the water was conducted from March 2022 to January 2023 in both the RDCI and the rice–crayfish continuous culture system (RCCC). The results showed that a total of 188 phytoplankton species and 92 zooplankton species were identified in the RDCI, whereas 152 phytoplankton species and 95 zooplankton species were detected in the RCCC. The phytoplankton community composition was similar between these two systems. For zooplankton, Rotifera was the dominant group. However, Chlorophyta and Bacillariophyta were the dominant phytoplankton groups. Compared with the RCCC, the RDCI exhibited lower plankton density during the crayfish-farming stage and overwintering stage, but higher plankton biomass during the crayfish-farming stage, overwintering stage, and rice maturity stage. The diversity indices, richness indices, and evenness indices of both phytoplankton and zooplankton in the RDCI were significantly higher than those in the RCCC. Correlation analysis indicated that water temperature, dissolved oxygen, total nitrogen, and ammonia nitrogen were the key environmental factors affecting plankton community structure. In summary, compared with the RCCC, the RDCI exhibits higher plankton diversity and better evenness, suggesting a more complex and stable community structure. The species composition of plankton and related indices indicate that the RDCI mitigates the degree of eutrophication in water during both the crayfish farming and the overwintering stages, while increasing nutrients levels during the rice planting stage. This approach is beneficial for reducing non-point-source pollution in agriculture and promoting green agricultural development. Full article

Afrotropical inland waters remain poorly studied for rotifer diversity. Here, we provide new distribution data from Botswana and connect these local patterns to continental-scale biogeography using an Africa–Europe occurrence dataset. In Botswana, we analyzed rotifer species richness, functional traits, and environmental drivers using 37 samples from 15 water bodies spanning natural and anthropogenic habitats. We recorded 107 rotifer taxa: 92 identified to species or subspecies level, 14 to genus, and one group of unidentified bdelloids. Seventy taxa (~65%) are new records for Botswana, and one species, Donneria sudzukii, is reported for the first time in Africa. Physicochemical gradients explained community structure, with the first two constrained RDA axes accounting for 40.7% and 23.7% of variation. Axis 1 captured a mineralization gradient linked to total dissolved solids and temperature, whereas Axis 2 reflected oxygen concentration and pH. Traits tracked these gradients: warmer, more mineralized waters were associated with specific trophi types, compact body shapes, and intermediate body sizes, whereas less mineralized, better oxygenated sites were related to smaller taxa and alternative feeding morphologies. To place these trait–environment relationships in a broader geographic context, we then analyzed an Africa–Europe dataset (67,170 records) to quantify latitudinal patterns in thermal classes and morphological traits (geometric body shape and trophi type). Diversity showed clear latitudinal structuring: warm-water genera clustered at low latitudes, only Kellicottia and Didymodactylos had mean distributions above 50° N, and bdelloid families were associated with higher latitudes. Morphological traits also varied with latitude, with trilateral truncated pyramid body shapes and malleoramate trophi occurring closest to the equator. Overall, by combining new species-level data from Botswana with continent-scale occurrence patterns, we link local community assembly to macroecological structure in rotifer functional and biogeographical organization. Full article

Zooplankton is an essential functional component of the aquatic food web, reflecting, through its structure and biomass, the impact of anthropogenic pressures on ecosystems. In this study, we investigated the traits of the Rotifera and Crustacea communities along a rural–urban gradient in the Colentina River system. The results revealed a partial separation between rotifers and crustaceans, with distinct distributions determined by trophic conditions and habitat type. Trophic indices (Carlson’s TSI, TSI_ROT, TSI_CR) indicated increased eutrophication in peri-urban and urban areas (Fundeni, Plumbuita) compared to rural reference ecosystems (Colentina, Crevedia). The relationships between Resource Use Efficiency (RUE) and trophic indices were positive and significant in rural areas, indicating a balanced ecosystem, but were decoupled in urbanised sectors, where high RUE values were driven by increased biomass of opportunistic species, whereas TSI indicated eutrophic conditions. The results confirm the role of zooplankton as a sensitive bioindicator, capable of capturing both the impact of eutrophication and the capacity of urbanised ecosystems to maintain trophic functionality. The integration of zooplankton-based metrics into monitoring schemes offers a complementary perspective on ecological resilience in aquatic ecosystems under urban pressures. Full article

In temperate freshwater ecosystems, zooplankton play a crucial role in the pelagic food web and act as sensitive indicators of environmental change. They respond to shifts in water temperature, hydrodynamic mixing, and short-term meteorological events. This study investigated the epilimnetic zooplankton fauna of Lake Karamurat (Bolu, Türkiye), a small tectonic temperate lake, with a specific focus on the influence of rainfall events and wind speed on community structure. The samples were taken seasonally and horizontally using a plankton net (55 µm mesh size) and were analyzed alongside in situ physico-chemical measurements and meteorological data. In total, 74 zooplankton taxa were identified, comprising 54 rotifer species and 20 crustacean species (16 Cladocera and 4 Copepoda). Testudinella greeni was recorded for the first time in Türkiye, representing a new addition to the Turkish Rotifera fauna. Multivariate analyses revealed that electrical conductivity, water temperature, dissolved oxygen, precipitation, and wind speed were key drivers shaping community composition. The findings suggest that wind-driven surface mixing and episodic rainfall events enhanced vertical redistribution, leading to dominance of rotifers and small-bodied cladocerans in the epilimnion. These findings underscore the critical role of sampling strategy in shallow lakes under dynamic conditions and provide new faunistic insights into the zooplankton diversity of Anatolian lakes. Full article

Understanding the structure of zooplankton communities in water contaminated with per- and polyfluoroalkyl substances (PFAS) is essential to the conservation of aquatic biodiversity. This study focused on the Weihe River and systematically characterized the PFAS pollution. By employing environmental DNA metabarcoding, multivariate statistics, and Partial Least Squares Path Modeling (PLS-PM), we systematically analyzed the associations between PFAS and zooplankton within the context of water parameters. The results showed that short-chain PFAS were the dominant PFAS compounds in the Weihe River (accounting for 70.89% of ΣPFAS), and that both PFAS and the zooplankton community exhibited similar spatial patterns. PLS-PM identified a key pathway: water chemistry promoted PFAS accumulation, which in turn exerted taxon-specific effects. Short-chain PFAS were primarily associated with Cercozoa, and path analysis indicated negative relationships, whereas long-chain PFAS were correlated with Ciliophora and Rotifera. Specific taxon within Ciliophora showed potential as bioindicators. Additionally, higher community relative abundance was associated with reduced diversity loss under anthropogenic stress, indicating a potential buffering response. Overall, short-chain PFAS, in combination with water parameters, were associated with higher ecological risk to zooplankton communities. This study highlights the importance of including indirect pathways and taxon-specific responses into risk assessments of emerging contaminants. Full article

Freshwater ecosystems are undergoing rapid species loss due to climate change and human impact. In this context, biomonitoring has become essential for species censusing and biodiversity conservation. In recent years, environmental DNA (eDNA) metabarcoding has emerged as a powerful, non-invasive alternative to traditional sampling and morphological identification methods. This study is the first to apply eDNA analysis to the characterization of invertebrate communities in the Oreto River, Sicily (Italy). Water samples were collected at three points of the river (upstream, midstream, downstream), and eDNA was extracted for metabarcoding. Overall, the analysis identified 40 species belonging to different phyla, including Annelida, Arthropoda, Cnidaria, Mollusca, Porifera and Rotifera. Twelve species appear to be newly recorded in Sicily, including confirmed identifications (Simulium trifasciatum, Rotaria rotatoria, Euchlanis dilatata, Lecane clostero-cerca) and other potential new identifications (Microchironomus tener, Micropsectra pallidula, Tinodes dives, Philodina flaviceps, Buchholzia appendiculata, Lecane bulla, Drosophila incompta, Corynoneura coronata). The study also confirmed the presence of alien species (Physella acuta, Craspedacusta sowerbii). Furthermore, species composition varied among the three sampling points, with most taxa detected in the upstream section. These results provide a preliminary snapshot of the biodiversity of river invertebrates, highlighting the potential of eDNA to complement traditional methods. Full article

As environmental indicators, invertebrate communities are closely related to changes in the water environment. Efficient and accurate monitoring of invertebrates is of great significance for providing references for water environment conservation. However, environmental DNA metabarcoding has rarely been used in invertebrate research at the Chai River in Kunming, Yunnan, China, and the current characteristics of invertebrate communities are unclear. Therefore, this study investigated the spatial and seasonal patterns of invertebrates and the environmental stressors of the Chai River. Based on eDNA metabarcoding, 873 ASVs of invertebrates belonging to Annelida, Arthropoda, Cnidaria, Gastrotricha, Mollusca, Nematoda, Platyhelminthes, Protozoa, and Rotifera were identified, with Arthropoda being the absolute dominant phylum. Distinct spatial and seasonal variations in the invertebrate communities (e.g., ASV number, dominant genera, relative abundances) were observed. Macrothrix and Acanthamoeba were the first and second most dominant genera, both in dry and wet periods. A spatial–seasonal heterogeneity of the relation between the invertebrate communities and environmental factors was observed in the Chai River. The water temperature (WT), chemical oxygen demand (COD), conductivity (C), and Chlorophyll-a (Chl-a) levels were deemed to be the crucial environmental factors influencing the distributions of invertebrate communities in the Chai River, which was consistent with the spatial and seasonal differences in pollution characteristics around the Chai River. This study provides insights into conserving the diversity of invertebrate communities and the management of the Chai River and similar agricultural rivers. Full article

Natural ecosystems, especially those regulated by floods, are sensitive to prolonged temperature fluctuations that affect hydrology and the lateral connection between the river and its floodplain. Here, we analyzed a series of zooplankton data collected monthly from 2007 to 2016 during the ice-free period in Kopački Rit Nature Park in the Middle Danube, an area important as a food source and nursery area for fish stocks in the Danube. The aim was to find out how the long-term change in temperature and fluctuating environmental parameters affect the succession of zooplankton in the warmer (from April to September) and colder parts of the year (from October to March). Throughout the decade, total nitrogen concentrations showed significant differences between years, with an increase since 2012. Despite the increase in nitrogen levels and the expected increase in primary production, the higher nitrogen levels were accompanied by lower zooplankton biomass. A significant difference was found between the values of the zooplankton geometric mean index, with 73% of the variance explained by the difference between groups. In general, a trend toward a significant decrease in zooplankton biomass, with a simultaneous increase in the number of species and high turnover rates, was observed throughout the decade. Full article

The role of abiotic factors in the allelopathic interactions between copepods and rotifers is poorly documented. Temperature has a marked effect on the metabolism of zooplankton. Therefore, the release of allelochemicals by copepods and the response of rotifers to them may change as temperatures increase. Here, we tested the effect of two temperatures (20 and 25 °C) on the population growth of Brachionus havanaensis cultured on a conditioned medium (CM) of Arctodiaptomus dorsalis and Eucyclops sp. The CM was obtained daily, separately, for the males and females of both copepod species at a density of 0.1 ind. mL⁻¹ for 24 h prior to experiments. In the controls and CM treatments, higher temperatures had a stimulatory effect on the population growth and the rate of population increase (r) of B. havanaensis. At 25 °C, the CM from the females and males of A. dorsalis caused >30% increase in r, but for the CM from Eucyclops sp., this effect was lower (<21%). At 20 °C, the r in the controls and CM treatments was not significantly different. The morphometry of B. havanaensis varied depending on the treatments. Compared to controls, longer loricae were recorded in the CM of male A. dorsalis at both temperatures. However, in the CM of female calanoids, longer rotifers were observed only at higher temperatures. At 20 °C, the CM from Eucyclops produced smaller loricae. The relationship between the lorica length and width of rotifers showed a linear relation but the slope differed among the treatments. Full article

We highlight the lack of researchers studying freshwater zooplankton in Latin America and contextualize it within the global extinction of taxonomists, global loss of biodiversity, and regional reality to visualize the intensity of this threat and possible strategies for addressing it. The scarcity of researchers working on freshwater zooplankton currently threatens the future of these studies in the world. This global trend of the decreasing interest of scientists and local governments in learning about this important component of freshwater biodiversity is more accentuated in Latin America by regional drivers, such as brain drain, a lack of support by stakeholders, and the absence of planning for the rational use and conservation of this essential natural resource. All these drivers interact and have more dramatic consequences for regional research due to the recent reduction in government funds for science in some of these countries. In the context of Global Change; a loss of biodiversity due to this fact; and the misuse of drainage basins, overexploitation, and regional pressures, the lack of researchers studying freshwater zooplankton and, in general, all aquatic life has emerged as a critical threat to the delicate equilibrium of these ecosystems. Within this situation, scientific integration through intra-regional and extra-regional collaboration networks has emerged as an unavoidable strategy for the survival and future strengthening of studies on biodiversity and the conservation of freshwater zooplankton in Latin America. The development of new technologies such as DNA barcoding, metabarcoding, and metagenomics has emerged as a solution to this problem. Nevertheless, they should be considered as new tools towards integrative taxonomy and not as replacements for taxonomical studies. Full article

Lake Maggiore is a deep subalpine lake that has been well studied since the last century thanks to a monitoring program funded by the International Commission for the Protection of Italian–Swiss Waters. The monitoring program comprises both abiotic and biotic parameters, including zooplankton pelagic organisms. In this study, we present a dataset of 15,563 records of population densities and standing stock biomass for zooplankton pelagic taxa recorded over 43 years (1981–2023). The long-term dataset is valuable for tracing changes in trophic conditions experienced by the lake during the last century (eutrophication and its reversal) and the impact of global warming. Zooplankton samples (Crustacea and Rotifera Monogononta) were collected within 0–50 m depth by vertical hauls with an 80 µm light plankton sampler. The sampling frequency was monthly, with the exception of the 2009–2012 period, which employed seasonal frequency. The estimation of zooplankton taxon abundance and of its standing stock biomass is crucial in order to quantify the flux of matter, energy, and pollutants up to the upper trophic levels of the food web. The dataset provided is also suitable for food web analysis because the zooplankton taxa have been classified according to their ecological roles (microphagous organisms; primary and secondary consumers). Full article

To elucidate the structural characteristics and environmental drivers of plankton communities in alpine reservoirs, we examined phytoplankton and zooplankton in the Daqing Reservoir (China) across 13 sampling sites. Redundancy analysis (RDA) and Pearson correlation analysis were employed to explore the relationships between plankton density and environmental factors, as well as between plankton diversity indices and environmental conditions. Key findings include: (1) A total of 80 phytoplankton species were identified, with Chlorophyta (37 species) as the dominant group, while 52 zooplankton species were primarily represented by Rotifera. (2) Phytoplankton diversity indices (Shannon: 3.07–4.21) suggested oligotrophic conditions, whereas zooplankton indices (Shannon: 1.40–3.08) indicated meso- to oligotrophic states. (3) RDA analysis revealed that phytoplankton distribution was influenced by chemical oxygen demand and total phosphorus, while zooplankton distribution was related to ammonia nitrogen. These results highlight the importance of targeted nutrient management strategies to protect water quality in alpine reservoirs. Full article

Liangzi Lake, a typical shallow lake in the middle reaches of the Yangtze River, is important for water resource and biodiversity conservation. With the development of urbanization, anthropogenic activities have posed serious threats to the water quality and biodiversity of Liangzi Lake. To assess the aquatic ecosystem health of Liangzi Lake, the structure, the environmental response, and the interactions of plankton were investigated in 2022 and 2023. The results indicated that water temperature was a pivotal factor regulating plankton dynamics, with the assemblage patterns predominantly shaped by the phytoplankton species, which were Bacillariophyta in spring and Chlorophyta in summer. In terms of the phytoplankton, dissolved oxygen and the N:P ratio significantly affect cyanobacteria distribution. The high biomass and abundance of cyanobacteria in summer highlight the potential risk of harmful algal blooms. In contrast to the phytoplankton, the zooplankton exhibited enhanced resilience to changes in the surrounding environment. Rotifera was the dominant group in summer in terms of both abundance and biomass. Most core genera of plankton were jointly identified by eDNA metabarcoding and microscopical analysis, and eDNA metabarcoding had advantages in revealing a higher diversity. However, some taxa among rotifers such as Liliferotrocha were only identified using microscopical analysis. Therefore, a combination of both the methods is recommended to better understand the structuring mechanisms of plankton assemblages in lake ecosystems. Full article

The Rotifera fauna of the Peruvian Andes remains significantly understudied, as evidenced by our findings from a limited sampling effort of 18 locations (15 samples from the Cusco region and three samples from Lake Titicaca). We identified 12 Monogononta and three species of Bdelloidea as potential new records for Peru, underscoring the region’s remarkable but largely unexplored biodiversity. Particularly notable is the addition of seven potentially new records to Peru’s fauna in Lake Titicaca based on only three samples, despite the well-documented zooplankton research history in this lake. This emphasizes the need for more comprehensive studies targeting the Rotifera fauna of Lake Titicaca, especially in littoral zones rich in microhabitats. Besides Lake Titicaca, our investigation mainly focused on high-altitude and groundwater-dependent habitats in the high Peruvian Andes in the Cusco region, where the Rotifera fauna had not been studied. Among the species identified there, five Monogononta and three Bdelloidea likely represent new records for Peru. These findings highlight the extent of unexplored biodiversity and emphasize the urgent need for more comprehensive taxonomy studies of Rotifera in Peru. Additionally, our research has identified two records new to the Neotropics: Notommata voigti and Macrotrachela musculosa. Full article

Macrophytes taxa composition determines microinvertebrates utilized as environmental indicators in freshwater ecosystems. This study was conducted in Shengjin Lake. In this lake, local communities have been practicing using sine fishing nets for fishing and this has a disrupting effect on macrophyte vegetation, even though it was the major for the disappearance of submerged vegetation before it was banned. As a result of this sine fishing net ban by the local authorities, the vegetation that had disappeared began to recover. Thus, this study investigated the role of architecturally differentiated macrophytes restoration effect on zooplankton communities’ diversity, abundance, and species composition; open water was used as a control. For this, the data were collected from different habitats via site 1 (open water) site 2, (free-floating), site 3 (emergent and submerged), site 4 (submerged), and site 5 (emergent) macrophytes. In the present study, the results demonstrated that the relative mean density of Rotifer was measured high which ranged from (219 ± 141–678 ± 401 ind L⁻¹), mainly dominated by Keratella cochlearis and Lecane cornuta species. Following Rotifera, Cladocera population density was reported high and ranged within (36 ± 6.2–262.5 ± 49.4 ind L⁻¹). The Cladocera group was dominated by Daphnia spp., Moina micura, Ceriodaphnia reticulata, and Chydorus latus species. Compared to Rotifer and Cladocera, Copepod community were recoded least with relative mean density ranged within (11.52 ± 2.22–85.5 ± 27 ind L⁻¹) and dominated by Microcyclops javanus, Thermodiaptomus galebi, and Sinocalanus doerrii species. From environmental variables and the zooplankton density relationship analyzed, the redundancy analysis (RDA) results indicated that Water Temperature, Chlorophyll a, Dissolved Oxygen, Total Phosphorus, and Ammonium Nitrogen were found the most influential variables on zooplankton communities. Stepwise regression correlation showed that Copepod and Cladocera were found more dependent on environmental factors. For instance, Nitrate Nitrogen was negatively correlated with Cladocera, Copepod, and total zooplankton biomass but positively with Cladocera diversity. Water Temperature showed a positive relationship with Rotifer diversity; however, both Chlorophyll a and Electrical Conductivity were correlated positively with Cladocera biomass. Species diversity by the Shannon–Wiener index (H) illustrated a dynamic trend among the monitored sites which ranged between (0.65–4.25). From the three groups of zooplankton communities in contrast to Cladocera and Copepod, Rotifer species obtained more diversity across the studied sites. The Cladocera diversity (H′) index indicated a similar tendency in all sites. However, more Copepod diversity (H′) was observed in site 4. In conclusion, this study results can provide valuable insights into the health and dynamics of the aquatic ecosystem to understand factors deriving ecological imbalance and develop an integrated approach for effective strategies for management and conservation. Full article