In the biomonitoring using environmental DNA (eDNA) analysis, the suppression of eDNA degradation has been an important issue to estimate accurately the presence of target species and their eDNA concentrations. A recently proposed eDNA preservation technique requires only the addition of benzalkonium chloride (BAC) to water samples and has been used for various studies as an alternative solution to

A dendritic or web-like network is a unique property of inland freshwater systems. The dispersal and movement of freshwater fish are restricted to a network of such waterways. Therefore, during dispersal or movement, fish have to select their way at each junction (i.e. the confluence of two channels) in the network, and their channel selection (route selection) would be reflected in the spatial variations

The study was conducted to understand the influence of interactions of atmospheric deposition with different land use surfaces and change in water chemistry of river Ganga through changes in runoff water quality. Four different land use surfaces in the catchment of the river Ganga, namely cemented, open fallow land, woodland and grassland were selected for data comparison. The results indicated that

We investigated the transfer of radiocesium and its behavior in living cells and cellular debris in a Chlamydomonas spp. bloom in a pond located approximately 5 km from the Fukushima Dai-ichi Nuclear Power Plant. A microalgal bloom in the pond was the dominant factor in determining the radiocesium concentration (Bq/L) of the > 0.45 μm pond water fraction. The water-to-algae transfer factor [(137Cs

Freshwater ponds besides being a source of potable water, also serve as a habitat for a range of aquatic organisms. The quality of the pond water is dependent on several interrelated parameters like physical, chemical and biological factors which render the water source either fit or unfit for consumption. In this communication, we have discussed the utilization of the desmids flora in assessing the

Knowing the interactions between exotic and native species is essential to establish possible threats to the local fauna. In this study, we assessed the use of food resources and diet overlap between a recently introduced snail, Sinotaia quadrata, and a native species, Pomacea canaliculata. We analyzed the gut content and stable isotope of snails and resources in a lowland stream where both species

A recent discovery of freshwater sponges in an unexplored hydrographic basin in north-western Australia provided the opportunity to investigate the genus Corvospongilla Annandale (Spongillida: Spongillidae) using integrative systematics. Emendation of the genus diagnosis is provided. A comparative analysis of a Corvospongilla global dataset of morphological traits together with biogeographic patterns

Underlying spatial and habitat attributes of a river network are crucial to comprehend the bio-spatial arrangements within it, the study of which suffers from a paucity of information. Despite several reports on various piscine assemblages, no study contributes to understanding the characteristic attributes of the freshwater habitats of the sub-Himalayan Terai–Dooars ecoregion. Therefore, this study

The distribution area of a species is determined by a combination of factors and since each species of aquatic insect has adapted to drastically changing environments along river channels, they are excellent targets for study. Considering these factors, we focused on three Ephemera mayflies inhabiting the Japanese Archipelago and investigate their niche differentiation patterns. A total of 29 study

Laguna de Bay is the largest multipurpose lake in the Philippines. Of the primary uses, fish cultivation and potable water production depend mainly on its water quality. Over the years, this tropical lake has been inundated with pollution from agricultural, industrial and domestic wastewaters. While new contaminants have emerged, traditional contaminants including heavy metals continue to threaten

Gnathopogon caerulescens is an endangered but commercially important fish in Lake Biwa, Japan. The population size of G. caerulescens has drastically reduced in the past decades, and there is a strong need to develop effective resource management frameworks for the sustainable use of this species. In the management of endangered species, it is important to monitor and grasp their distribution and abundance

Lakes provide continuous records of past regional and global climate. Most studies utilize single trench section dig from the lake shore margins or from single core in the central part/depocenter of the lakes for paleoclimate reconstruction. These reconstructions are based on the assumption of homogenous sedimentation across the lake. However, single core approach for paleoclimate reconstruction is

The water-level regime is a major determinant of the community structure in river-floodplain systems. Chironomidae is a highly diverse insect family that plays a key role in the trophic structure and functioning of floodplain systems. However, we know little about how water-level oscillations affect the chironomid structure. Using a 9-year database, we investigated how the richness, density, and temporal

Recently, environmental DNA (eDNA) metabarcoding techniques have been applied to biodiversity investigations in aquatic ecosystems. However, no study has yet tested whether this technique is effective for water bodies in which extensive algal blooms break out. In this study, fish eDNA metabarcoding was carried out in Lake Taihu, which experiences extensive algal blooms, to confirm whether the technique

Bacalar Lake is characterized by a high saturation of calcium, bicarbonate, sulfate and silicate in its water and these conditions harbor a microbialite community. To explore the nematode fauna, associated with microbialites, 11 sites along the lake were selected. The collected microbialites were carefully dissolved and nematodes extracted manually. Nematodes were represented by 2 classes, 10 orders

Antibiotics are widely used for disease prevention in animal husbandry, including on chicken, cow and pig farms. Manure from farm animals can be used as fish food, especially in small-scale fish farming. Antibiotic residues and bacteria from the manure may spread to the fishpond water, which can lead to the emergence of antibiotic-resistant waterborne pathogens. This study focused on the antibiotic

Southern South America, especially Patagonia, presents numerous glacial lakes holding proxies of past environmental and climate changes. This is useful to reconstruct past environmental changes, key for understanding Southern Hemisphere variability and the present. Our aim was to identify the volcanic and environmental impact that occurred during the last 700 year in Northern Patagonia (Argentina)

How a population adapts to environmental changes is a central topic in ecology, but long-term changes in the phenotype of an organism have rarely been studied in aquatic systems. In this study, we examined the morphological changes in Daphnia pulex from the initial establishment stage, using paleolimnological analysis, in Lake Fukami-ike (Nagano Prefecture, Japan). We measured morphological traits

The differences between temperate and tropical seasonality suggest that ecological models developed for temperate streams do not necessarily apply to tropical streams. While detritus is the base of the temperate zone stream food webs, we expected a seasonal alternation in the energy source in tropical streams (i.e., increase in the autochthonous energy source in the dry season, and an increase in the

The lipid and fatty acid content of benthopelagic scavenging amphipods Ommatogammarus flavus and O. albinus from different depths of Lake Baikal were studied. These amphipods, known to move across a wide range of depths in Lake Baikal, had a relatively high level of total lipids (up to 46% dry weight) in comparison to other aquatic amphipods. This high level of total lipids resulted from a high concentration

Anthropogenic impacts have been reported as one of the main causes of eutrophication in freshwater systems and nutrient availability, mainly from discharges, are key to cyanobacteria development and harmful cyanobacteria blooms (cyanoHABs) upsurge. As these scenarios are common in the Azores, a cyanobacteria monitoring program was implemented in the lakes of the archipelago, which comprises cyanobacteria

The conversion of riparian vegetation into monocultures alters the input of allochthonous energy and the heterotrophy of streams. Here, we aimed to assess the implication of leaf litter inputs from plant species of agricultural importance on decomposition in Amazonian streams. We hypothesized that decomposition is low in litter with high concentrations of lignin and cellulose, regardless of the origin

Climate change is causing frequent and large floods, creating a need for information regarding the impact of severe flood disturbances on stream invertebrates. We briefly describe the response of invertebrate assemblages to an extreme flood event in 2018 in the western Ehime Prefecture of Japan. We compared invertebrate data collected in past regional-scale surveys with those gathered by revisiting

Vertical circulation reaches the bottom of the deepest (> 90 m) part of the northern basin of Lake Biwa, a warm monomictic lake, during winter (January to March) every year. In winter 2019, we found non-circulated water masses at the bottom of the lake where the basin is 90 m deep. This is the first observation of an incomplete vertical circulation event since we started monitoring Lake Biwa in 1979

Changes in river environments due to elevation gradients have a great impact on living organisms. In particular, with respect to aquatic insects, it has been recognized that even in closely related species there is a tendency for species to be replaced between upstream and downstream environments. Such a distribution tendency has also been suggested for the three species of the genus Ephemera of interest

Metacommunity structure of stream invertebrates is contingent on complex interplays between species dispersal ability, spatial extent and watershed environmental specificities. Previous studies showed that high diversity of Chironomidae (Insecta, Diptera) is observed in southern Brazilian montane streams, although the knowledge of the processes driving such high diversity is poorly comprehended. In

Dams disrupt the longitudinal gradient and decrease the natural connectivity of lotic systems and change the physical, chemical, and biological compartments of the river environment. Here, we investigated the effects of damming and seasonal variation in environmental conditions and richness, density, taxonomic and functional beta diversity patterns of phytoplankton, through dry and rainy seasons (of

In Lake Biwa, picocyanobacteria blooms usually occur during the summer–autumn thermal stratification period. Intriguingly, a novel bloom was detected in winter 2015–2016, in which picocyanobacterial cell density increased by one order of magnitude despite lower water temperature, suggesting the possibility that “cold-water-preference” species dominate in the picocyanobacterial community. In the present

Natural fluctuations in ecosystems, such as those associated with climate, are a fundamental factor structuring macroinvertebrate assemblages. Given that macroinvertebrates are widely used in biomonitoring of aquatic systems, it is necessary assess the potential effects of seasonality on this group to avoid confusing its effects with the effects of anthropogenic impacts. In the present study, the richness

Daphnia, keystone herbivores in lakes, routinely produce immediately hatching eggs; additionally, they also produce resting eggs enveloped by an ephippial case, a thickened carapace that allows population survival under harsh environmental conditions. To examine differences in ephippial morphology between Daphnia species in different subgenera, we conducted microscopic observations and genetic analyses

Blooms of green macroalgae (Ulva spp.) occur frequently in the hypereutrophic Yatsu tidal flat of eastern Japan. In this study, to elucidate the effects of such blooms on nutrients and sulfide dynamics, we measured Ulva nutrients uptakes and stocks, and sulfide release during Ulva blooms decay. NH4+ uptake was greater than NO3– uptake when NH4+ was sufficient, whereas NO3– uptake increased in the absence

In recent years, biodiversity loss has become one of the most serious environmental issues worldwide, especially in aquatic ecosystems. To avoid diversity loss, it is necessary to monitor biological communities, and environmental DNA (eDNA) metabarcoding has been developed as a rapid, noninvasive, and cost-effective method for aquatic biodiversity monitoring. Although this method has been applied to

Testate amoebae are an irreplaceable key component of microbial communities in many aquatic and soil ecosystems and well known as useful bioindicators. In the present work, testate amoebae compositions in different-type biotopes of freshwater waterbodies of North Vietnam were investigated for the first time. A total of 80 species and subspecies belonging to 12 genera and 8 families were identified

Although Cyclops vicinus Uljanin, 1875 and C. kikuchii Smirnov, 1932 are broadly distributed in Eurasia, the genetic divergences between European and Asian populations have been investigated in neither species. In Japan, the nomenclature and distinction between these two congeners are still questionable (thus, hereafter C. vicinus s.l.). We determined the taxonomic position of the Japanese C. vicinus

Understanding the role of abiotic and biotic factors on biological communities is a challenge for ecologists. Individuals of the order Odonata have a close connection with these factors, which can influence the establishment of each stages of live. This study evaluated the relationship between habitat complexity and limnological variables on the diversity of Libellulidae larvae and adults. Our hypotheses

Exotic species have invaded freshwater ecosystems, causing biodiversity loss of associated communities. We investigated the influence of the invasive macrophyte Hydrilla verticillata on taxonomic and functional richness, and on taxonomic and functional beta diversity of associated Chironomidae community, comparing this macrophyte with the structurally similar native macrophyte, Egeria najas. We conducted

Multi-proxy analysis of lake sediments provides high-resolution and reliable palaeoclimate records. The present study aims to investigate the palaeoenvironmental changes and eutrophic evolution of the Wular Lake, Kashmir Valley spanning the last ~ 500 years. Based on the multi-proxy analysis and supported by radiocarbon chronology, two prominent environmental phases were identified. From 74 to 45 cm

Spatial synchrony occurs when local populations exhibit correlated dynamics over time. Recent studies, both experimental and observational, have indicated that the magnitude of spatial synchrony, in cross-species analyses, is correlated with the level of specialization. In theory, specialist species would exhibit higher levels of synchrony than generalist species because they would be more sensitive

Insufficient knowledge about ecology of weed macrophytes from a large-scale perspective narrows the necessary decision-making for biodiversity conservation. The present study aimed to assess the occurrence frequency of Egeria densa in lotic and lentic/semi-lotic environments from a Brazilian dammed river, as well as to quantify the attributed explanation (pure or combined) by limnological and spatial

Estimating the presence and abundance of non-native species in the early stage of invasion is important to prevent further spread of non-native species in aquatic systems. Environmental DNA (eDNA) methods have been applied for aquatic plants; however, it is still questionable on the accuracy of the eDNA methods for the detection and abundance estimation of aquatic plants in lotic systems. Here, we

This study investigated temporal changes in the vertical distribution of invertebrates during periods of low flows in the Tafna wadi, a semi-arid Mediterranean river characterised by a general decline in average flows. The hyporheos was sampled along a 130-m stretch at depths of 0.3, 0.6 and 1 m in a pool-riffle sequence and a lateral gravel bar. Benthic fauna was collected on each sampling occasion

To examine how compositional changes in a community vary depending on time scales, we estimated temporal β-diversity of zooplankton in Lake Hataya Ohnuma, a small lake in Yamagata, Japan. The zooplankton community was monitored for 9 years with monthly samplings. We estimated the inter-annual, inter-seasonal, intra-seasonal, and inter-month β-diversity with the magnitude of sampling errors, and examined

Environmental DNA (eDNA) is an emerging approach for detecting species, yet numerous methodological questions remain unanswered. Here we examined how time to filtration (0–48 h after collection) and sample storage (open vs. chilled in the dark) influenced detection and measured eDNA concentration. Water samples kept in the dark and chilled had no significant decrease in detection or eDNA concentration

Optical water types (OWTs) can represent diverse ranges of Chlorophyll-a (Chl-a), total suspended matter (TSM), and colored dissolved organic matter (CDOM) concentrations, which make them extremely useful for monitoring water quality, for example, detecting eutrophic conditions or tuning remote sensing algorithms. In this study, the objective is to assess OWTs found in Brazilian waters using in situ

Cyanobacteria are the major producers of the taste and odour compounds geosmin and 2-methylisoborneol (2-MIB) in drinking water and fish worldwide. In recent years, the outbreaks of cyanobacteria blooms in Tri An and Dau Tieng Reservoirs, Vietnam have led to an increase attention in taste and odour problems. In the present study, the two off-flavour compounds geosmin and 2-MIB were found in field samples

The Cimanuk River with a total watershed area of 4010.8 km2 flowing from the Garut Regency to Indramayu Delta is the longest in West Java Province. However, the cumulative effects of climate change, increased population, and fish farming in the coastal area have continuously pressured the availability of water resources in its watershed. This study was, therefore, aimed to analyze the impact of land

A semi-enclosed river-mouth bay (Kojima Bay) and the artificial lake within it (Kojima Lake) were studied to examine their nutrient storage and export processes and characteristics. The aim of this study was to perform mass balance analysis using long-term monitoring and historical accumulation data of phosphorus (P) via 210Pb measurements of accumulated sediment. The results are then compared with

Phylloicus (Trichoptera, Calamoceratidae) is a stream invertebrate widely distributed across Neotropical biomes, which larvae use allochthonous leaf litter as food resource and to build a case that offers protection against predation. Seasonal changes in leaf litter accumulation on the streambed may affect Phylloicus larvae due to variations in availability of food and case-building material; however

Allochthonous organic matter in low-order streams is, in general, mainly composed of senescent leaves. However, in tropical streams green leaves can represent an important source of energy. The present study evaluated the decomposition of green and senescent leaves in Amazonian streams using leaves of three plant species: Inga stipularis D.C. 1876, Tococa guianensis Aubl. 1775 and Vochysia ferruginea

North African streams and rivers face multiple anthropogenic stressors, and their aquatic fauna is rapidly dwindling before comprehensive knowledge of their distribution and ecology has been attained. We investigated the distribution and life cycle of the Maghrebian endemic Ecdyonurus rothschildi Navás, 1929 in northeastern Algeria. The species was recorded both from permanent and intermittent freshwater

Northern ecosystems are experiencing rapid and large-scale changes driven by accelerated warming, which have profound effects on the terrestrial and freshwater biodiversity. A comprehensive understanding of the distribution of aquatic biodiversity of subarctic ecosystems is therefore needed to better predict future trajectories of their unique biodiversity. In this study, we examined the functional

The objective of this study was to develop a hydro-chemical model using the Soil and Water Assessment Tool (SWAT) and to evaluate the climate change impacts on discharge and nitrate-nitrogen loads from Ise Bay watersheds (the Kiso, Nagara, Ibi, and Shonai rivers). Using a regional climate model, through the dynamic downscaling approach, present and future climate data were generated at a 2 km spatial

Research on carbon gas flux to and from inland waters has increased over the past two decades, driven mainly by the need to understand (1) the global carbon budget in regard to stabilizing earth’s climate, and (2) how aquatic ecosystems and the services they provide change in response to anthropogenic pressures like climate and land use change. This paper reviews carbon flux research in support of

This study aims to confirm the effect of a small stream impoundment on phosphorus and nitrogen dynamics in a suburban watershed. The results show that the phosphate concentration in the water body was significantly higher than that in the inflowing water under ordinary flow conditions. The phosphorus promotes algal growth that causes significant diurnal dissolved oxygen variation because of photosynthesis

Controlling phosphorous (P) loads from rice fields is important for the conservation of aquatic ecosystems, in part because P is relatively concentrated at its sources. Recently, winter flooding, by which irrigation water is maintained in rice fields during winter, has attracted much attention as a farming strategy for environmental conservation and biodiversity maintenance. However, the effects of

A total of 24 soil samples, including 4 subsurface, 34 water samples and 17 sets of hydrological survey data were collected in a soil investigation and hydrological survey campaign from August 2017 to September 2018 at a small Dermawan forest catchment, Singapore. The study was to understand and evaluate the catchment’s soil and stream status through the assessment of elemental concentrations and their

In the original publication of the article the sentence under the heading “Primer and probe design” was published incorrectly. The correct sentence is given in this correction.

DNA barcoding has been actively used as a method for species identification, and it will become an increasingly important method in the future. However, DNA barcoding can occasionally encounter a major problem, namely “nuclear mitochondrial DNA pseudogenes (NUMTs)”. In this paper, we report the discovery of a pseudogene in the mitochondrial COI region from aquatic heteropterans. PCR with Folmer’s universal

Hermaphroditic individuals in the population of Chinese crucians [Carassius auratus (Linnaeus, 1758)] in Chany Lake (Western Siberia) were recorded during a water level regression phase between 2006 and 2014. This period was characterized by critical conditions affecting crucian spawning because of increasing water salinity and a wide amplitude of water temperature fluctuations in the shallow spawning

Water flow velocity is a strong environmental filter structuring benthic communities in lotic ecosystems. While many studies have determined its effect on the distribution and diversity patterns of insects, the role of water flow velocity on other groups of aquatic invertebrates (i.e., Oligochaeta) has remained unexplored. We sampled five lotic ecosystems to investigate the influence of water flow