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ABSTRACT Freshwater biodiversity conservation has received substantial attention in the scientific literature and is finally being recognized in policy frameworks such as the Global Biodiversity Framework and its associated targets for 2030. This is important progress. Nonetheless, freshwater species continue to be confronted with high levels of imperilment and widespread ecosystem degradation. An Emergency Recovery Plan (ERP) proposed in 2020 comprises six measures intended to “bend the curve” of freshwater biodiversity loss, if they are widely adopted and adequately supported. We review evidence suggesting that the combined intensity of persistent and emerging threats to freshwater biodiversity has become so serious that current and projected efforts to preserve, protect and restore inland‐water ecosystems may be insufficient to avert substantial biodiversity losses in the coming decades. In particular, climate change, with its complex and harmful impacts, will frustrate attempts to prevent biodiversity losses from freshwater ecosystems already affected by multiple threats. Interactions among these threats will limit recovery of populations and exacerbate declines resulting in local or even global extinctions, especially among low‐viability populations in degraded or fragmented ecosystems. In addition to impediments represented by climate change, we identify several other areas where the absolute scarcity of fresh water, inadequate scientific information or predictive capacity, and a widespread failure to mitigate anthropogenic stressors, are liable to set limits on the recovery of freshwater biodiversity. Implementation of the ERP rapidly and at scale through many widely dispersed local actions focused on regions of high freshwater biodiversity and intense threat, together with an intensification of ex‐situ conservation efforts, will be necessary to preserve native freshwater biodiversity during an increasingly uncertain climatic future in which poorly understood, emergent and interacting threats have become more influential. But implementation of the ERP must be accompanied by measures that will improve water, energy and food security for humans – without further compromising the condition of freshwater ecosystems. Unfortunately, the inadequate political implementation of policies to arrest widely recognized environmental challenges such as climate change do not inspire confidence about the possible success of the ERP. In many parts of the world, the Anthropocene future seems certain to include extended periods with an absolute scarcity of uncontaminated surface runoff that will inevitably be appropriated by humans. Unless there is a step‐change in societal awareness of – and commitment to – the conservation of freshwater biodiversity, together with necessary actions to arrest climate change, implementation of established methods for protecting freshwater biodiversity may not bend the curve enough to prevent continued ecosystem degradation and species loss. [ABSTRACT FROM AUTHOR]

Inland waters have an important role in increasing fishermen's income, satisfying community nutritional needs, providing food security for the community, functioning as habitats for aquatic organisms, and maintaining environmental balance. The gap in fish resource management in Inland Water is that many problems in Inland Water have not been revealed and are not well documented. For this reason, it is necessary to collect references to review the problems and challenges of fish resource management in Inland Waters, as well as provide solutions so that Inland Water Fisheries can be sustainable. Inland water fisheries' problems in Indonesia are sedimentation, pollution, habitat destruction, lack of fishways, and overfishing. To reduce sedimentation, deforested land on the hillsides must be replanted. Green belts on the banks of reservoirs should not be used for agriculture and settlements, and must have a good master plan for land use, and sediment dredging should be carried out regularly. To tackle pollution from fish farming activities in inland waters, fish farming in reservoirs/ lakes must not pollute the waters, and the amount must match the carrying capacity. To deal with pollution from industry, waste must be treated first before being discharged into water. Dams in rivers must be equipped with fishways so that fish can migrate. To overcome overexploitation, the number and types of large fishing gear, such as liftnets, filtering device, active seine, and active barrier, along with fishing using poisons, chemicals, or electricity, must be monitored and punished. Based on the findings in the review that explain the problem and how to overcome it, fish resource management has a chance of success if it is good in its management. [ABSTRACT FROM AUTHOR]

Given the significance of fish farming as a promising sector of Ukraine’s agriculture, and the Mykolaiv, Odesa, and Kherson regions are characterised by a significant number of natural and artificial water bodies, the study of aquatic bioresource catching indicators in the south is both important and timely. The research aimed to determine trends in aquatic bioresource catching in southern Ukraine during the period 2018-2023 and to analyse the factors influencing the extraction of aquatic bioresources. This article presents overall catch statistics, as well as catch data for inland waters of the south and aquaculture conditions over the past six years. It has been established that the catch of aquatic biological resources in southern Ukraine has been declining each year from 2018 to 2023. The negative trends in aquatic bioresource catching, both in aquaculture and natural water bodies, are linked to several factors. In particular, the decline in catches has been influenced by: COVID-19; the unstable military and political situation in Ukraine, associated with Russian military aggression; outdated material and technical base of fishing enterprises; lack of government subsidies and foreign investment in the sector; imperfections in the systems of control and regulation of the extraction of aquatic bioresources; and irrational use of the bioproductive potential of water bodies in southern Ukraine. Based on a scientific analysis of the dynamics of aquatic bioresource extraction in southern Ukraine and the identification of key factors contributing to the decline in catches, a set of measures has been developed to positively impact the fishing industry. These measures include: attracting foreign investment in fish farming; improving the quality of monitoring, regulation, and control over aquatic bioresource catching at local, regional, and state levels; restoring critical fish farming infrastructure damaged by Russian aggression; ensuring sustainable fisheries management; and introducing EU best practices into Ukrainian fish farming. The scientific results obtained from this research can be used in practice to ensure the sustainable development of fisheries in southern Ukraine

East African lakes support the food and water security of millions of people. Yet, a lack of continuous long-term water quality data for these waterbodies impedes their sustainable management. While satellite-based water quality retrieval methods have been developed for lakes globally, African lakes are typically underrepresented in training data, limiting the applicability of existing methods to the region. Hence, this study aimed to (1) assess the accuracy of existing and newly developed water quality band algorithms for East African lakes and (2) make satellite-derived water quality information easily accessible through a Google Earth Engine application (app), named LAndsat water QUality retrieval tool for east African lakes (LAQUA). We collated a dataset of existing and newly collected in situ surface water quality samples from seven lakes to develop and test Landsat water quality retrieval models. Twenty-one published algorithms were evaluated and compared with newly developed linear and quadratic regression models, to determine the most suitable Landsat band algorithms for chlorophyll-a, total suspended solids (TSS), and Secchi disk depth (SDD) for East African lakes. The three-band algorithm, parameterised using data for East African lakes, proved the most suitable for chlorophyll-a retrieval (R2 = 0.717, p < 0.001, RMSE = 22.917 μg/L), a novel index developed in this study, the Modified Suspended Matter Index (MSMI), was the most accurate for TSS retrieval (R2 = 0.822, p < 0.001, RMSE = 9.006 mg/L), and an existing global model was the most accurate for SDD estimation (R2 = 0.933, p < 0.001, RMSE = 0.073 m). The LAQUA app we developed provides easy access to the best performing retrieval models, facilitating the use of water quality information for management and evidence-informed policy making for East African lakes. [ABSTRACT FROM AUTHOR]

Effective monitoring and management of inland waterbodies depend on reliable assessments of water quality through remote sensing technologies. Match-up analysis plays a significant role in investigating the comparability between in situ and remote sensing data of physical and biogeochemical variables. By exploring different spatial aggregations and temporal windows, we aimed to identify which configurations are most effective and which are less effective for the assessment of remotely sensed water quality data within the context of governmental monitoring programs. Therefore, in this study, remote sensing data products, including the variables of Secchi depth, chlorophyll-a, and turbidity, derived from the Copernicus satellites Sentinel-2 and Sentinel-3, were compared with in situ laboratory data from >100 waterbodies (lakes and reservoirs) in Germany, covering a period of 5 years (2016–2020). Processing was carried out using two different processing schemes, CyanoAlert from Brockmann Consult GmbH and eoapp AQUA from EOMAP GmbH & Co. KG, in order to analyze the influence of different processors on the results. To investigate appropriate spatial aggregations and time windows for validation (the match-up approach), we performed a statistical comparison of different spatial aggregations (1 pixel; 3 × 3, 5 × 5, and 15 × 15 macropixels; and averaging over the whole waterbody) and time windows (same day, ±1 day, and ±5 days). The results show that waterbody-wide values achieved similar accuracies and biases compared with the macropixel variants, despite the large differences in spatial aggregation and spatial variability. An expansion of the temporal window to up to ±5 days did not impair the agreement between the in situ and remote sensing data for most target variables and sensor–processor combinations, while resulting in a marked rise in the number of matches. [ABSTRACT FROM AUTHOR]

The provision of accurate wet tropospheric corrections (WTC), accounting for the delay of the radar pulses caused mostly by the atmospheric water vapor in the altimeter‐range observations, is pivotal for the full exploitation of altimeter‐derived surface heights. The WTC is best retrieved by measurements from Microwave Radiometers (MWR) on board the same altimeter mission. However, these instruments fail to provide valid WTC over land and ice and under rainy conditions. The GNSS‐derived Path Delay Plus (GPD+) algorithm has been designed to provide WTC over these surfaces where the onboard MWR WTC is invalid. This study focuses on the estimation of enhanced GPD+ WTC for the Copernicus Sentinel‐3A and Sentinel‐3B satellites, for the latest Baseline Collection 005.02 (BC005.2), spanning the period since the beginning of the missions until March 2023. GPD+ corrections are being provided operationally since 2022 and have been adopted as the default WTC in the calculation of the sea level anomaly (SLA). Compared to previous versions, the BC005.2 GPD+ WTC features improved data combination procedures, possesses a larger percentage of points estimated from observations, a better intermission alignment and reduced systematic differences among ascending and descending passes. Overall, GPD+ WTC are consistent, calibrated corrections, valid over all points present in the Non Time Critical marine product, allowing to recover, on average, about 17% of the altimeter observations with valid SLA, which otherwise, most of them would be rejected. Impacts of these WTC are most significant over coastal and inland water regions, at high latitudes and during rain events. Plain Language Summary: Satellite radar altimetry is a powerful technique to measure the Earth's topography during day and night, in all weather conditions. It uses radar pulses to measure the distance between the satellite and the surface beneath the satellite, from which the height of the mean sea level, rivers and lakes, for example, can be obtained. The atmosphere affects the propagation by delaying the signal and increasing the measured trajectory. The effect of the atmospheric water vapor is particularly difficult to model, since it is highly variable. This study concerns with a method to estimate the so‐called wet tropospheric correction, which accounts for the water vapor effects in the altimeter measurements. Over open ocean, the correction is usually based on the measurements from a dedicated instrument collocated on the same satellite, which fails to provide valid information over non‐water surfaces. The method, called GNSS‐derived Path Delay Plus (GPD+), aims to fill the gaps left by the previous instrumental correction. The study describes the latest version of the GPD+ wet tropospheric corrections for the Copernicus Sentinel‐3 altimeter products. It is demonstrated that these corrections can extend the altimeter observations to important regions such as coastal regions, rivers and lakes and high latitudes. Key Points: New GPD+ wet tropospheric corrections have been produced for Sentinel‐3, for the latest Baseline Collection (BC) 005.02These corrections are consistent, calibrated, valid over all surface types, improving data coverage mainly over coastal and polar regionsGPD+ are improved wet tropospheric corrections with respect to the Sentinel‐3 onboard radiometer and to the European Centre for Medium Range Weather Forecasts (ECMWF) operational model [ABSTRACT FROM AUTHOR]

Given the significance of fish farming as a promising sector of Ukraine's agriculture, and the Mykolaiv, Odesa, and Kherson regions are characterised by a significant number of natural and artificial water bodies, the study of aquatic bioresource catching indicators in the south is both important and timely. The research aimed to determine trends in aquatic bioresource catching in southern Ukraine during the period 2018-2023 and to analyse the factors influencing the extraction of aquatic bioresources. This article presents overall catch statistics, as well as catch data for inland waters of the south and aquaculture conditions over the past six years. It has been established that the catch of aquatic biological resources in southern Ukraine has been declining each year from 2018 to 2023. The negative trends in aquatic bioresource catching, both in aquaculture and natural water bodies, are linked to several factors. In particular, the decline in catches has been influenced by: COVID-19; the unstable military and political situation in Ukraine, associated with Russian military aggression; outdated material and technical base of fishing enterprises; lack of government subsidies and foreign investment in the sector; imperfections in the systems of control and regulation of the extraction of aquatic bioresources; and irrational use of the bioproductive potential of water bodies in southern Ukraine. Based on a scientific analysis of the dynamics of aquatic bioresource extraction in southern Ukraine and the identification of key factors contributing to the decline in catches, a set of measures has been developed to positively impact the fishing industry. These measures include: attracting foreign investment in fish farming; improving the quality of monitoring, regulation, and control over aquatic bioresource catching at local, regional, and state levels; restoring critical fish farming infrastructure damaged by Russian aggression; ensuring sustainable fisheries management; and introducing EU best practices into Ukrainian fish farming. The scientific results obtained from this research can be used in practice to ensure the sustainable development of fisheries in southern Ukraine. [ABSTRACT FROM AUTHOR]

Macrophytes, which are foundational to freshwater ecosystems, face significant threats due to habitat degradation globally. Habitat suitability models are vital tools used to investigate the relationship between macrophytes and their environment. This study addresses a critical gap by developing a Geographic information system-based HSM tailored for small lakes, which are often overlooked in ecological studies. We included various abiotic predictors to model the potential macrophyte habitat for several small lakes in southern Bavaria (Germany). Key factors such as the distance to groundwater inflow, depth, availability of photosynthetically active radiation (PAR), and littoral slope were identified as significant predictors of macrophyte occurrence. Notably, the HSM integrates remote sensing-based data to derive PAR availability at the growing depths of the macrophytes using Sentinel-2 MSI data. Integration of an MSI-based time series of PAR availability enabled the introduction of a temporal component allowing monitoring and predicting changes in macrophyte habitats over time. The modeled habitat suitability score correlates highly (R = 0.908) with macrophyte occurrence. We see great promise in using habitat modeling for macrophytes as a tool for water management; in particular, the use of Sentinel-2 MSI data for habitat suitability modeling holds promise for advancing water management. By demonstrating the efficacy of GIS- and remote sensing-based HSM, we pave the way for future applications of this innovative approach in ecological conservation and resource management. [ABSTRACT FROM AUTHOR]

Humans and water have a complex relationship that includes various dimensions such as sociocultural, political, legal and ecological. Considering the ubiquity of water, we need a more holistic perspective to help us see water not as a static entity but rather as one in constant movement, physically and conceptually; acknowledging the interplay between water and humans is essential to understanding societal narratives deeply embedded in places. In this special section, an interdisciplinary group of scholars explore inland waters, taking a water‐centric view instead of a land‐centric one. The special section delves into the emerging hydro‐social connections, diverse forms of expertise, governance models, collective and spontaneous actions, and resilience strategies within the context of inland water bodies, exploring how canals, rivers and wetlands are experienced and represented as places. The papers in this collection show that any form of placemaking should take responsible stewardship of water, embrace its dynamic nature, and present a realistic pathway towards sustainable solutions for present and future water challenges. [ABSTRACT FROM AUTHOR]

Environmental changes and human impact can alter biodiversity in negative manners that affect mankind's sustainable development. Particularly, such effects on inland waters are even more concerning, as those ecosystems play essential roles in sustaining human life as well as relevant wildlife. Thus, in this study, we investigated such effects on microbial diversity in inland waters in Vietnam using bacterial communities in sediment as indicators. To do this, we collected sediment samples from various locations in three respective regions (Red river in the north, Ba river in the central area, and Mekong delta flood zone in the south) using standard methods, extracted their total DNA, sequenced their V3-V4 16S rRNA gene fragments using an Illumina Miseq platform and analyzed the sequences to infer the diversity of the bacterial communities in the samples. These communities were compared in terms of richness (alpha diversity) and composition (beta diversity), and the correlations between their diversity levels and environmental factors, as well as human activities, were analyzed by using standard statistical tools. Our results showed that the communities were different from each other solely by region, in richness and critically in composition, although there were some communities distinctively different from all the others. Among environmental factors, only water salinity (and conductivity) had negative correlations with alpha-diversity indices of the bacterial communities, and phosphate concentration and turbidity had positive correlations, while the other factors had almost no correlations, which partially explains the region-specific diversity. These results also suggest that climate change incidences, especially sea intrusion, can have significant effects on microbial diversity in inland waters. The impact of human activities did not appear severe, solely affecting bacterial community richness, but not significantly affecting bacterial community composition. However, apparently reduced bacterial diversity in several sites with intense human impacts and distinct environmental conditions should be noted and deserve further investigation. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of the impact of contaminants on organisms requires consideration of magnitude, duration, frequency, and life-history stage of exposure. Government guidelines provide a benchmark to evaluate exposure magnitude, but solely assessing magnitude does not consider duration and frequency of exposure. High-frequency sampling of data enables better integration of temporal patterns of potential environmental stressors and can inform research about habitat suitability. We develop and demonstrate an approach to examine temporal dynamics of abiotic conditions using high-frequency sampling data to assess water quality in the habitat of a Canadian federally listed endangered fish species, the Redside Dace (Clinostomus elongatus). Urban stressors, including chloride and non-point source pollutants, are considered contributing factors to the decline of Redside Dace in Canada. We collected and analyzed conductivity/chloride data from nine Redside Dace sites with varying degrees of upstream urbanization in the Greater Toronto Area to understand spatial and temporal variation in chloride exposure. Chloride loading in the region is largely driven by application of winter de-icing salt contributing to year-round elevated chloride concentrations. We highlight chloride patterns during critical early life stages of Redside Dace (spring spawning through summer; ‘non-salting season’), when sensitivity to stressors may be heightened. We assessed our data against the federal Canadian and American guidelines and found that at six out of nine sites, critical early life stages were exposed to chloride concentrations that exceeded the magnitude threshold of Canadian guidelines. We found instances of chronic duration threshold exceedance at six out of nine sites. Future research can leverage our approach to identify areas of concern where magnitude and duration thresholds are exceeded, and our results can be used to inform the duration of stressor exposure to critical life-history stages during ecologically relevant laboratory-based ecotoxicology studies. We emphasize that our approach can be used for any environmental parameter sampled with high frequency to better understand temporal regimes of ecological stressors.

Environmental changes and human impact can alter biodiversity in negative manners that affect mankind’s sustainable development. Particularly, such effects on inland waters are even more concerning, as those ecosystems play essential roles in sustaining human life as well as relevant wildlife. Thus, in this study, we investigated such effects on microbial diversity in inland waters in Vietnam using bacterial communities in sediment as indicators. To do this, we collected sediment samples from various locations in three respective regions (Red river in the north, Ba river in the central area, and Mekong delta flood zone in the south) using standard methods, extracted their total DNA, sequenced their V3-V4 16S rRNA gene fragments using an Illumina Miseq platform and analyzed the sequences to infer the diversity of the bacterial communities in the samples. These communities were compared in terms of richness (alpha diversity) and composition (beta diversity), and the correlations between their diversity levels and environmental factors, as well as human activities, were analyzed by using standard statistical tools. Our results showed that the communities were different from each other solely by region, in richness and critically in composition, although there were some communities distinctively different from all the others. Among environmental factors, only water salinity (and conductivity) had negative correlations with alpha-diversity indices of the bacterial communities, and phosphate concentration and turbidity had positive correlations, while the other factors had almost no correlations, which partially explains the region-specific diversity. These results also suggest that climate change incidences, especially sea intrusion, can have significant effects on microbial diversity in inland waters. The impact of human activities did not appear severe, solely affecting bacterial community richness, but not significantly affecting bacterial community composition. However, apparently reduced bacterial diversity in several sites with intense human impacts and distinct environmental conditions should be noted and deserve further investigation.

The McMurdo Dry Valleys (MDV), Antarctica’s largest ice-free region, hosts unique terrestrial ecosystems, with biodiversity concentrated in the aquatic environments and surrounding soils. Despite being a scientific hub, the creation of the MDV Antarctic Specially Managed Area (ASMA) made significant steps toward protecting the environment from degradation from human usage. However, with sustained human presence within the MDV, increasing human activity across Antarctica, and aquatic ecosystems subject to environmental change, the effectiveness of current protections for biodiversity conservation requires evaluation. This study employs spatial analysis of MDV protected areas, streams, lakes, research camps, and tourist sites to assess the robustness of current protections, identify underprotected areas, and outline steps for future protection. Within the MDV ASMA, five smaller Antarctic Specially Protected Areas (ASPAs) exist. Only two ASPAs contain streams, and only one with a full hydrologic catchment. With roughly 6% of the lotic habitat area protected by ASPAs, the MDV fall short of global goals for freshwater protection. Past successful management of the MDV shows the effectiveness of collaboration and early action, and amongst calls for ASPA network expansion and restructuring, the MDV has the opportunity to be at the forefront again and increase the protection of Antarctic aquatic ecosystems.

ABSTRACTMonitoring rapidly changing inland water bodies using remote sensing requires a temporal resolution of at least 3 days and a spatial resolution of at least 30 meters. However, the current satellite data falls short of meeting these monitoring requirements. Spatiotemporal fusion (STF) presents an effective method for obtaining continuous high-resolution data. This study explores five established STF algorithms, namely Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM), Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM), Robust Adaptive Spatial and Temporal Fusion Model (RASTFM), Flexible Spatiotemporal Data Fusion (FSDAF) and Unmixing-Based Data Fusion (UBDF), through experimentation across 45 lakes worldwide. Results are comprehensively compared and analyzed using two indicators: Root Mean Square Error (RMSE) and Robert’s edge (Edge) based on a dataset that contains 360 image pairs collected in 2021. The five algorithms underwent 950 random experiments. The results indicate that: (1) ESTARFM outperforms the other four algorithms in terms of visual effect and accuracy assessment. Its average RMSE of and EDGE are 0.0023 sr−1 and −0.0419, respectively. Followed by: FSDAF (RMSE: 0.0026 sr−1, EDGE: −0.0584), RASTFM (RMSE: 0.0029 sr−1, EDGE: −0.4128), STARFM (RMSE: 0.0027 sr−1, EDGE: −0.5207), and UBDF (RMSE: 0.0030 sr−1, EDGE: −0.6505) algorithms. (2) the algorithms have varied performance in different water monitoring missions: for water body extraction, the ESTARFM and FSDAF algorithms are recommended; for algae bloom detection, the FSDAF algorithm is recommended; for seasonal water body monitoring, the ESTARFM is recommended; for quantitative monitoring, the ESTARFM, FSDAF, and UBDF algorithms are recommended. (3) STARFM-like algorithms are sensitive to radiometric uncertainties and UBDF algorithm is sensitive to spatial uncertainties. The findings of this study can help generate high spatiotemporal resolution remote sensing datasets for water quality monitoring, waterbody detection, algae bloom tracking, and other water environmental monitoring missions.

Morphological and molecular comparisons of clupeoid fishes in lakes Tumba and Mai-Ndombe in the Congo Basin revealed that a large-sized form of a common species in Lake Mai-Ndombe had not been distinguished from the small-sized endemic Mai-Ndombe dwarf sprat Nannothrissa stewarti Poll & Roberts, 1976 in ecological studies. The large-sized form differs from the Mai-Ndombe dwarf sprat in several morphological characters and resembles the smalltoothed pellonula Pellonula leonensis Boulenger, 1916, but in barcoding analysis appears more closely related to the bluntnosed sawtooth pellonuline Potamothrissa obtusirostris (Boulenger, 1909). This large-sized form is probably a species new to science but will remain undescribed for now, and is here referred to as Pellonulinae sp. BIG. A slender clupeoid, also from Lake Mai-Ndombe, has recently been referred to as the Lake Tumba dwarf sprat Nannothrissa parva (Regan, 1917), which would be the first record of this species from that lake. Specimens of a slender clupeoid collected from Lake Mai-Ndombe for this study were identified as the losera fangtooth pellonuline Odaxothrissa losera Boulenger, 1899. This is the first confirmed occurrence of this species in Lake Mai-Ndombe, whereas the presence of N. parva could not be confirmed. The phylogenetic analysis strongly supports the genus Nannothrissa as currently delimited, here barcoded for the first time, but also confirms the previously reported mismatch between morphological classification and molecular data in this group. We further note that the Mai-Ndombe dwarf sprat attains a larger size than the maximum size noted in the original description in 1976, and it is suggested that an intense beach-seine fishery that utilises mosquito nets might have led to a population decline followed by decreased intraspecific competition, enhancing individual growth. For the same reason, Pellonulinae sp. BIG might have been less common previously and so remained undetected until now. [ABSTRACT FROM AUTHOR]

The social structure of inland fisheries communities tends to place powerful elites in important positions, while local fishermen are subordinate actors. Patronage is a form of social relationship that describes the unequal social structure between these actors. This research aimed to analyze social structure in the inland waters of South Sumatra in the practice of the Lebak Lebung and River Auction (L3S) in OKI District. To achieve this goal, a constructivist paradigm with qualitative research methods was employed, and the sample comprised 39 informants selected as subjects. The data analysis was conducted in three distinct stages, namely data reduction, presentation, and drawing conclusions. The results showed that the regulation of open access for all parties in the local government regime after 1982 created an institutionalized social relations structure where the government, investors, traders, middlemen, and non-fishing actors dominated compared to the fishermen. The participants in this social landscape strived to accumulate capital to enhance their competitiveness within the L3S domain. A patronage system was implemented with middlemen assuming the role of patron and the fishermen acting as their clients. The current institutional social structure has created an unfair distribution of resource benefits for fishing workers. The novelty theories were found in the working relations of the inland waters community of South Sumatra, namely stratified distribution of rights, dual status, multi-stage patronage, and the positive function of patronage for chief fisherman. Further research should be conducted to research policy revitalization and develop strategic inland water management models. [ABSTRACT FROM AUTHOR]

This paper presents a bibliometric analysis of the publications on carbon emission from inland waters (CEW) in the past 10 years (2011-2020). The study in this paper utilizes the Scopus database, which enables the retrieval of 6303 related documents. The findings of the study showed that the amount of CEW research has consistently increased over the years, and is expected to grow rapidly in the future. China and USA are the top publishing sources on CEW worldwide, with the Chinese Academy of Sciences being the top leading institution. The research in this field has focused on the CO2 source identification, the impact of environmental factors on CEW, the reduction of carbon emissions, as well as the energy usage performance and efficiency. This comprehensive study not only enhances the understanding of current CEW research among scholars and managers but also provides a historical reference for future research. [ABSTRACT FROM AUTHOR]

Following several surveys of aquatic Coleoptera during 2013-2018 in northern Western Ghats, India, we hereby provide an illustrated checklist with modified keys to the species of families Dytiscidae, Gyrinidae, Noteridae, and Hydrophilidae. To date, we have collected 69 species of true water beetles, adding new occurrence records for two species to the fauna of the state. Keys are modified from the works of various authors. Distribution records are provided with district specific records for Maharashtra. Keys, species lists, and distribution records are based on our survey results. Species were identified following the works of various authors, and affirmed by dissecting male genitalia. Provided with keys are habitus images, images of male genitalia for 59 species, and digital drawings & scanning electron micrographs of taxonomically important structures wherever necessary. These surveys were conducted to revive the work on aquatic beetles that have been neglected for about 40 years, and to prepare a revised checklist. [ABSTRACT FROM AUTHOR]

Abstract The provision of accurate wet tropospheric corrections (WTC), accounting for the delay of the radar pulses caused mostly by the atmospheric water vapor in the altimeter‐range observations, is pivotal for the full exploitation of altimeter‐derived surface heights. The WTC is best retrieved by measurements from Microwave Radiometers (MWR) on board the same altimeter mission. However, these instruments fail to provide valid WTC over land and ice and under rainy conditions. The GNSS‐derived Path Delay Plus (GPD+) algorithm has been designed to provide WTC over these surfaces where the onboard MWR WTC is invalid. This study focuses on the estimation of enhanced GPD+ WTC for the Copernicus Sentinel‐3A and Sentinel‐3B satellites, for the latest Baseline Collection 005.02 (BC005.2), spanning the period since the beginning of the missions until March 2023. GPD+ corrections are being provided operationally since 2022 and have been adopted as the default WTC in the calculation of the sea level anomaly (SLA). Compared to previous versions, the BC005.2 GPD+ WTC features improved data combination procedures, possesses a larger percentage of points estimated from observations, a better intermission alignment and reduced systematic differences among ascending and descending passes. Overall, GPD+ WTC are consistent, calibrated corrections, valid over all points present in the Non Time Critical marine product, allowing to recover, on average, about 17% of the altimeter observations with valid SLA, which otherwise, most of them would be rejected. Impacts of these WTC are most significant over coastal and inland water regions, at high latitudes and during rain events.

Abstract: Aim Assessing the damage caused to natural environments and native biodiversity by alien species is challenging. We tested whether the number of detections of alien species is affected by total alien or total invader alien species richness, considering the importance of predicting which species are more probable future invaders. Methods We summarized a research information survey conducted on alien amphibians, annelids, aquatic macrophytes, cnidarians, crustaceans, fish, microorganisms, mollusks, nemathelminths, platyhelminths, and reptiles, and for Brazilian watersheds. We used linear regressions between detections and total alien species richness and between detections and invader species richness. Results We obtained 1,896 alien detections of 183 aquatic species in Brazil. Fish and mollusk species were the commonest invaders due to their detections being more frequent than expected by chance, considering all the alien species occurring in Brazilian freshwater ecosystems. We also found positive and robust linear relationships between alien species detections and alien species richness. Conclusions Our results illustrate how Brazilian freshwater systems are fragile to alien invasions and highlight the need for effective action to address this question. Scientific uncertainty in Brazil regarding the status of some alien species and their potential harm is high, highlighting the need for a cautionary overview of invaders. Despite this scenario, new policies create opportunities for aquatic parks with exotic organisms to spread further in Brazil, which, in actual Brazilian conditions, is likely to increase the pressure on natural ecosystems and native species. This reinforces the already expressed need by the scientific community for greater attention to the issue.

Abstract The social structure of inland fisheries communities tends to place powerful elites in important positions, while local fishermen are subordinate actors. Patronage is a form of social relationship that describes the unequal social structure between these actors. This research aimed to analyze social structure in the inland waters of South Sumatra in the practice of the Lebak Lebung and River Auction (L3S) in OKI District. To achieve this goal, a constructivist paradigm with qualitative research methods was employed, and the sample comprised 39 informants selected as subjects. The data analysis was conducted in three distinct stages, namely data reduction, presentation, and drawing conclusions. The results showed that the regulation of open access for all parties in the local government regime after 1982 created an institutionalized social relations structure where the government, investors, traders, middlemen, and non-fishing actors dominated compared to the fishermen. The participants in this social landscape strived to accumulate capital to enhance their competitiveness within the L3S domain. A patronage system was implemented with middlemen assuming the role of patron and the fishermen acting as their clients. The current institutional social structure has created an unfair distribution of resource benefits for fishing workers. The novelty theories were found in the working relations of the inland waters community of South Sumatra, namely stratified distribution of rights, dual status, multi-stage patronage, and the positive function of patronage for chief fisherman. Further research should be conducted to research policy revitalization and develop strategic inland water management models. Highlight Research The author mentioned 3 highlights from their results research: • Auction system in inland waters in South Sumatra presents an unfair distribution for fishermen. • Structure of the working relationship formed is an asymmetric patron-client relationship but with novel theories such as the stratified distribution of rights model, dual status, multi-stage patronage, and the positive function of patronage. • An imbalance in local access to auction objects due to their weak ability to accumulate capital.

Water reflectance anisotropy has serious implications for the remote sensing of water surfaces. The ${\bm{f}^{\prime}}/{\bm{Q}}$ factor serves as a crucial bridge connecting the inherent and apparent optical properties of turbid water bodies; ${\bm{f}^{\prime}}/{\bm{Q}}$ varies not only with angular geometry and inherent optical properties (IOPs), but also with wavelength. However, there was limited research on ${\bm{f}^{\prime}}/{\bm{Q}}$ in turbid water bodies. This research conducted preliminary exploration on ${\bm{f}^{\prime}}/{\bm{Q}}$ in inland turbid water bodies based on measurements of in-situ multi-angle bidirectionality reflectance, including 17 angles and 251 bands when the solar zenith angle (${{\bm{\theta }}}_{\bm{s}}$) was between 40° and 50°. This study indicated that ${\bm{f}^{\prime}}/{\bm{Q}}$ exhibited highly sensitivity in the wavelength range of 690–750 nm with a peak near 727 nm, as well as angular geometry played an important role in the BRDF. The ${\bm{f}^{\prime}}/{\bm{Q}}$ varied over the range of 0.13–0.18 sr−1, variation of 0.06 sr−1 across different bands, when viewing zenith angle (${{\bm{\theta }}}_{\bm{v}}$) and particle backscattering ratio (${{\tilde{\bm{b}}}}_{{\bm{bp}}}$) were 0 and 0.0183, respectively; higher than the range observed for the ocean (0.08–0.15 sr−1). The variability in ${\bm{f}^{\prime}}/{\bm{Q}}$ as a function of wavelength must be accounted for in turbid waters. The ${\bm{f}^{\prime}}/{\bm{Q}}$ was correlated with the IOPs in the range of 690–750 nm, with coefficient of determination (R2) values higher than 0.94 and root mean square error (RMSE) values lower than 0.004. Our findings are of great significance for understanding the relationship between inherent and apparent optical properties in inland water bodies, for BRDF studies, and for improving the accuracy of satellite product retrieval.

Freshwater algal blooms have caused ecological damage and public health concerns throughout the world. Monitoring such blooms via in situ sampling is both costly and time-consuming, and satellite imagery provides a rapid and relatively inexpensive way to supplement these techniques. Sentinel-2 MultiSpectral Imager data have effectively detected chlorophyll-a, a proxy for algal biomass, in large bodies of water, but few studies have shown the applicability in small (

This paper critically reviews the progress in ecosystem integrity (health) assessment of inland waters and provides future directions for assessment. Current biotic integrity assessments mainly use multimetric indices and predictive models to evaluate overall health status; the criteria largely rely on pristine reference sites, but such an approach is not applicable to unique natural waters and irreversibly modified waters. Biotic diagnostic assessments are still in the exploratory stage and can only diagnose possible stressor types and wide-ranges of their intensities through empirical models linking stressors and species-trait-indices. Current chemical integrity assessments mainly use criteria determined by small-scale ecotoxicity tests, rather than quantitative relationships developed between chemical factors and biotic effects in real ecosystems, thus potentially under or overestimating pollutant toxicity. Current physical integrity assessments focus on overall habitat quality, rather than quantitative habitat requirements, and thus cannot provide quantitative support for ecological restoration and conservation. Current hydrological integrity (environment flow) assessments largely depend on quantitative relationships between hydrological regimes with a few species and single groups, rather than with whole communities, and fail to comprehensively diagnose hydrological causes of biotic resource decline. In the future, integrity assessments need to be based on ecosystem integrity requirements of ecosystem service targets: first, there is a need to build quantitative relationships between biotic integrity and ecosystem services, assess requirements of community structure and function for service goals, and establish biotic integrity assessment methods; second, we must build quantitative relationships between biotic integrity and abiotic integrity in real ecosystems, assess chemical, physical, and hydrological integrity requirements of biotic needs, and establish diagnostic assessment methods. [ABSTRACT FROM AUTHOR]

The evolving dynamics of climate change and water resource management present unique challenges for the research and conservation of archaeological heritage, particularly within reservoirs. The Dolmen of Guadalperal in Spain and its surrounding archaeological sites exemplify such a scenario. This study is dedicated to the development and application of a comprehensive methodology for archaeological documentation and site detection, integrating an array of approaches including Synthetic Aperture Radar (SAR) from Sentinel‐1, photogrammetric restitution using historical imagery and geometric recording of sites with diverse sensing equipment. A distinctive aspect of this research lies in juxtaposing multibeam sonar data, typically associated with underwater surveys, with standard land‐based documentation methods like photogrammetry and LiDAR. The results demonstrate the effectiveness of integrating data from these diverse techniques in detecting new archaeological sites and monitoring their alterations, which could be potentially harmful. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate atmospheric optical characteristics over the Gorky and Cheboksary Reservoirs and their multi-scale temporal variations to obtain the background characteristics and to identify events involving the transfer of absorbing aerosol to the studied region in 2022–2023. The region is located at a considerable distance (500 km) from the nearest AERONET station; therefore, previous atmospheric data were not available. As a solution, the in situ self-measured aerosol optical depth (AOD) and Angström exponent, as well as satellite products (MAIAC and CALIPSO) for MODIS data, were used. This allowed us to set background values of an AOD of 0.11 at a wavelength of 500 nm and an Angström exponent of 1.2, against their maximum values of 0.38 and 2.5, respectively. To explain these variations, the registered conditions and the microstructure of the dust aerosol over the studied region are presented. For days with background values, the analysis of the particle size distribution data did not show a predominance of any particle size. The optical properties of a smoke aerosol in an atmospheric column are described, and an analysis of the dynamics of particle size variability is presented. A comparative analysis of the optical characteristics of atmospheric aerosol over the Gorky and Cheboksary Reservoirs using in situ and MODIS products was carried out. [ABSTRACT FROM AUTHOR]

Verification of the C-band geophysical model functions (GMF) for the open ocean and the Gorky reservoir was carried out using Sentinel-1 IW-mode Synthetic aperture radar (SAR) images. CMOD5.N, CMOD7, GMF for the Caspian Sea, and CSARMOD2 were considered. The motivation for this study is concerned with the clarification of applying C-band GMFs for SAR images including for the conditions of inland water bodies, as well as with the study of the influence of various wind speed direction sources on the results of wind speed magnitude retrieval for ocean conditions. Comparison of wind speed from the CMOD5.N algorithm using wind direction data from NOAA NDBC oceanographic buoys together with the data provided by NCEP reanalysis data showed that regardless of the geographic location, the result does not depend significantly on the choice of the wind direction source. Novel results of CMOD5.N, CMOD7, GMF for the Caspian Sea, and CSARMOD2 applications to the conditions of the Gorky reservoir are presented. The comparison of these results with the meteorological station measurements showed the best agreement for CMOD5.N. The preliminary results on the construction of new C-band GMF adjusted to the Gorky Reservoir have shown statistical parameters better than for Caspian Sea GMF and CSARMOD2. [ABSTRACT FROM AUTHOR]

Inland waters are an import source of greenhouse gases for the atmosphere. In particular, the emissions of methane from lakes and reservoirs are suspected of almost offsetting the terrestrial carbon sink. However, the estimates found in the literature are subject to large uncertainties due to both missing data and methodological limitations. In particular, there is a gap of observations in the temperate climate zone, and data are especially scarce from eutrophic waters despite the fact that the emissions increase with the degree of eutrophication. We present data from a eutrophic reservoir in the temperate climate zone, measured continuously with a floating eddy-covariance system. Data from two seasons are analyzed, both starting and ending with spring and autumn mixing, respectively, and including the complete period of summer stratification. During the spring and summer months, clear diurnal patterns for the carbon dioxide fluxes were detected in the eddy covariance data reflecting the interplay between photosynthesis and respiration. However, this daylight-driven oscillation weakened with the onset of autumn and disappeared at the end. In contrast to the carbon dioxide fluxes, the methane fluxes did not show any daytime dynamics. Notwithstanding, distinct seasonal patterns with increasing CH4 emissions over summer appeared. The carbon dioxide balance was about −9.8 and −71.0 g C m−2, in the first and second season, respectively. Thus, based on the eddy covariance measurements, the reservoir was a carbon dioxide sink in both study periods. However, the difference between the two seasons indicates a distinct inter-annual variability. The seasonal methane emissions were 24.0 g C m−2 and 23.2 g C m−2, respectively. Accordingly, the seasonal carbon budget resulted in 15.1 g C m−2 and −47.8 g C m−2, respectively, meaning the reservoir was a carbon source in the first and a sink in the second study period. However, considering the significant higher warming potential of methane and transposing these emissions into carbon dioxide equivalents, the reservoir contributed to the greenhouse potential of the atmosphere in both study periods.

East African lakes support the food and water security of millions of people. Yet, a lack of continuous long-term water quality data for these waterbodies impedes their sustainable management. While satellite-based water quality retrieval methods have been developed for lakes globally, African lakes are typically underrepresented in training data, limiting the applicability of existing methods to the region. Hence, this study aimed to (1) assess the accuracy of existing and newly developed water quality band algorithms for East African lakes and (2) make satellite-derived water quality information easily accessible through a Google Earth Engine application (app), named LAndsat water QUality retrieval tool for east African lakes (LAQUA). We collated a dataset of existing and newly collected in situ surface water quality samples from seven lakes to develop and test Landsat water quality retrieval models. Twenty-one published algorithms were evaluated and compared with newly developed linear and quadratic regression models, to determine the most suitable Landsat band algorithms for chlorophyll-a, total suspended solids (TSS), and Secchi disk depth (SDD) for East African lakes. The three-band algorithm, parameterised using data for East African lakes, proved the most suitable for chlorophyll-a retrieval (R2 = 0.717, p < 0.001, RMSE = 22.917 μg/L), a novel index developed in this study, the Modified Suspended Matter Index (MSMI), was the most accurate for TSS retrieval (R2 = 0.822, p < 0.001, RMSE = 9.006 mg/L), and an existing global model was the most accurate for SDD estimation (R2 = 0.933, p < 0.001, RMSE = 0.073 m). The LAQUA app we developed provides easy access to the best performing retrieval models, facilitating the use of water quality information for management and evidence-informed policy making for East African lakes.

Effective monitoring and management of inland waterbodies depend on reliable assessments of water quality through remote sensing technologies. Match-up analysis plays a significant role in investigating the comparability between in situ and remote sensing data of physical and biogeochemical variables. By exploring different spatial aggregations and temporal windows, we aimed to identify which configurations are most effective and which are less effective for the assessment of remotely sensed water quality data within the context of governmental monitoring programs. Therefore, in this study, remote sensing data products, including the variables of Secchi depth, chlorophyll-a, and turbidity, derived from the Copernicus satellites Sentinel-2 and Sentinel-3, were compared with in situ laboratory data from >100 waterbodies (lakes and reservoirs) in Germany, covering a period of 5 years (2016–2020). Processing was carried out using two different processing schemes, CyanoAlert from Brockmann Consult GmbH and eoapp AQUA from EOMAP GmbH & Co. KG, in order to analyze the influence of different processors on the results. To investigate appropriate spatial aggregations and time windows for validation (the match-up approach), we performed a statistical comparison of different spatial aggregations (1 pixel; 3 × 3, 5 × 5, and 15 × 15 macropixels; and averaging over the whole waterbody) and time windows (same day, ±1 day, and ±5 days). The results show that waterbody-wide values achieved similar accuracies and biases compared with the macropixel variants, despite the large differences in spatial aggregation and spatial variability. An expansion of the temporal window to up to ±5 days did not impair the agreement between the in situ and remote sensing data for most target variables and sensor–processor combinations, while resulting in a marked rise in the number of matches.

Macrophytes, which are foundational to freshwater ecosystems, face significant threats due to habitat degradation globally. Habitat suitability models are vital tools used to investigate the relationship between macrophytes and their environment. This study addresses a critical gap by developing a Geographic information system-based HSM tailored for small lakes, which are often overlooked in ecological studies. We included various abiotic predictors to model the potential macrophyte habitat for several small lakes in southern Bavaria (Germany). Key factors such as the distance to groundwater inflow, depth, availability of photosynthetically active radiation (PAR), and littoral slope were identified as significant predictors of macrophyte occurrence. Notably, the HSM integrates remote sensing-based data to derive PAR availability at the growing depths of the macrophytes using Sentinel-2 MSI data. Integration of an MSI-based time series of PAR availability enabled the introduction of a temporal component allowing monitoring and predicting changes in macrophyte habitats over time. The modeled habitat suitability score correlates highly (R = 0.908) with macrophyte occurrence. We see great promise in using habitat modeling for macrophytes as a tool for water management; in particular, the use of Sentinel-2 MSI data for habitat suitability modeling holds promise for advancing water management. By demonstrating the efficacy of GIS- and remote sensing-based HSM, we pave the way for future applications of this innovative approach in ecological conservation and resource management.

Inland waters are significant, yet highly uncertain, natural sources of nitrous oxide (N2O). Many emission models assume that N2O is only emitted from freshwaters, and that N2O sink behavior is negligible. However, observational studies have reported N2O undersaturation, suggesting that inland waters can act as N2O sinks due to net N2O consumption. This study leverages data from the National Ecological Observatory Network (NEON) and an existing global emission model to examine the prevalence of and controls on N2O undersaturation in streams, rivers, and lakes across scales and biomes. We find that N2O undersaturation is prevalent in the NEON data set (14%–30% of samples) and process‐based model outputs (38%), occurring across biomes and spatial scales. Failing to account for undersaturation in the NEON data set could result in an 100% overestimation of N2O emissions. These results show that consideration of N2O sink behavior is needed for accurate emission estimates. Plain Language Summary: Nitrous oxide (N2O) is a climate‐relevant greenhouse gas that is increasing in the atmosphere due to human activities. It also contributes to stratospheric ozone depletion. Inland waters (e.g., streams, rivers, and lakes) are significant, yet uncertain, sources of N2O to the atmosphere. In general, emission models assume that N2O is produced in and emitted from inland waters. However, field observations have shown that inland waters can also act as sinks of atmospheric N2O, potentially offsetting emissions. Understanding when and where inland waters act as N2O sinks is needed for accurate emission estimates. This study uses a large observational data set and an existing global emission model to explore when, where, and to what extent inland waters act as N2O sinks. The results show that N2O sink behavior is common and may significantly offset emissions. Key Points: Nitrous oxide (N2O) undersaturation in inland waters is prevalent, indicating that inland waters periodically act as sinks of atmospheric N2OPeriodic N2O sink behavior occurs at most monitored sites and the frequency of N2O sink behavior is invariant to ecosystem size or biomeN2O sink behavior has the strong potential to partially offset N2O emissions from inland waters [ABSTRACT FROM AUTHOR]

Existing studies on central Chilean inland waters only mention records of decapods, but there are no ecological studies about decapods and other crustacean groups. The aim of the present study was a first characterization of inland water crustaceans in Claro River, a Mediterranean-climate river from Chile. The results of redundance analysis (RDA) revealed that the crab Aegla affinis inhabits waters of high pH and low temperature values, whereas amphipods of the genus Hyalella inhabit habitats with high pH, high temperatures, and low values of dissolved oxygen. Finally, ostracods (family Cyprididae), isopods (Heterias sp.) and the southern river crayfish (Samastacus spinifrons) inhabit water systems with moderate values of pH, temperature, dissolved oxygen, and conductivity. This paper represents the first ecological report for crustaceans of central Chilean inland waters, and the results appear to be similar to comparable descriptions for northern Patagonian rivers. [ABSTRACT FROM AUTHOR]

The interaction between climate warming and alien fish invasions could have severe consequences in inland waters, which represent isolated environments with high biodiversity richness. Due to the current climatic trend, increasing water temperatures and salinization, shorter ice cover period, and altered flow regimes are predicted for these environments. The aim of this review is to offer a comprehensive analysis at a global scale of the recent studies available in the literature, focused on the responses of invasive freshwater fish to the effects of climate change in both lotic and lentic environments. To achieve this purpose, we selected 34 relevant papers, using the Scopus and Google Scholar database. New alien species establishment, distribution range expansion of species already introduced, and exacerbating impacts on freshwater ecosystems and the native fish communities they host were included in the topics covered by the analyzed papers. Despite the uncertainties related to the unpredictability with which the effects of global warming will occur, the findings of the selected studies served as a support to evaluate conservation and management implications, with particular reference to possible mitigation strategies. [ABSTRACT FROM AUTHOR]

The aim of the research is to identify the optimal method for smoothing the surface of a hybrid digital bathymetric model (HDBM). The initiation of this research is justified by the fact that a model created from diverse types of data may have different surface textures and outliers. This diversity may cause problems in subsequent data processing stages, such as generating depth contours. As part of the adopted research methodology, fifteen filters were analysed. Filtering techniques were examined for filter type, the number of iterations, weights, and window size. The result is the adopted research methodology, which enabled the selection of the optimal filtering method. The research undertaken in this work is an extension of the methodology for developing an HDBM. An important aspect of the research is the approach to elaborating on such kinds of models in shallow and ultra-shallow waters adjacent to the land, as well as the use of data obtained by modern measurement platforms, such as unmanned surface vehicles (USV) and unmanned aerial vehicles (UAV). The studies fit into the general context of works related to the development of this type of model and undoubtedly provide a solid reference for further development or improvement of similar methods. [ABSTRACT FROM AUTHOR]

Aquatic ecosystems are particularly vulnerable to the introduction of non-indigenous species (NIS), leading to multi-faceted ecological, economic and health impacts worldwide. The Iberian Peninsula comprises an exceptionally biodiverse Mediterranean region with a high number of threatened and endemic aquatic species, most of them strongly impacted by biological invasions. Following a structured approach that combines a systematic review of available information and expert opinion, we provide a comprehensive and updated multi-taxa inventory of aquatic NIS (fungi, macroalgae, vascular plants, invertebrates and vertebrates) in Iberian inland waters. Moreover, we assess overall patterns in the establishment status, introduction pathways, native range and temporal introduction trends of listed NIS. In addition, we discuss the legal coverage provided by both national (Spanish and Portuguese) and European NIS regulations. We inventoried 326 aquatic NIS in Iberian inland waters, including 215 established, 96 with uncertain establishment status and 15 cryptogenic taxa. Invertebrates (54.6%) and vertebrates (24.5%) were the groups with the highest number of NIS, with Arthropoda, Mollusca, and Chordata being the most represented phyla. Recorded NIS originated from diverse geographic regions, with North and South America being the most frequent. Vertebrates and vascular plants were mostly introduced through intentional pathways (i.e. release and escape), whereas invertebrates and macroalgae arrived mostly through unintentional ways (i.e. contaminant or stowaway). Most of the recorded NIS were introduced in Iberian inland waters over the second half of the 20th century, with a high number of NIS introductions being reported in the 2000s. While only 8% of the recorded NIS appear in the European Union list of Invasive Alien Species of Union concern, around 25% are listed in the Spanish and Portuguese NIS regulations. This study provides the most updated checklist of Iberian aquatic NIS, meeting the requirements set by the EU regulation and providing a baseline for the evaluation of its application. We point out the need for coordinated transnational strategies to properly tackle aquatic invasions across borders of the EU members. [ABSTRACT FROM AUTHOR]

Inland and coastal waters provide key ecosystem services and are closely linked to human well-being. In this study, we propose a semi-analytical method, which can be applied to Sentinel-2 MultiSpectral Instrument (MSI) images to retrieve high spatial-resolution total suspended solids (TSS) concentration in a broad spectrum of aquatic ecosystems ranging from clear to extremely turbid waters. The presented approach has four main steps. First, the remote sensing reflectance (R rs) at a band lacking in MSI (620 nm) is estimated through an empirical relationship from R rs at 665 nm. Second, waters are classified into four types (clear, moderately turbid, highly turbid, and extremely turbid). Third, semi-analytical algorithms are used to estimate the particulate backscattering coefficient (b bp) at a reference band depending on the water types. Last, TSS is estimated from b bp at the reference band. Validation and comparison of the proposed method with three existing methods are performed using a simulated dataset (N = 1000), an in situ dataset collected from global inland and coastal waters (N = 1265) and satellite matchups (N = 40). Results indicate that the proposed method can improve TSS estimation and provide accurate retrievals of TSS from all three datasets, with a median absolute percentage error (MAPE) of 14.88 %, 31.50 % and 41.69 % respectively. We also present comparisons of TSS mapping between the Sentinel-3 Ocean and Land Colour Instrument (OLCI) and MSI in Lake Kasumigaura, Japan and the Tagus Estuary, Portugal. Results clearly demonstrate the advantages of using MSI for TSS monitoring in small water bodies such as rivers, river mouths and other nearshore waters. MSI can provide more detailed and realistic TSS estimates than OLCI in these water bodies. The proposed TSS estimation method was applied to MSI images to produce TSS time-series in Lake Kasumigaura, which showed good agreements with in situ and OLCI-derived TSS time-series. [ABSTRACT FROM AUTHOR]

Seasonal wetlands are complex ecosystems highly dependent on climatic variation due to their small size and shallowness. Wetlands are carbon (C) reservoirs and the major fraction of the C is in the dissolved phase as part of the dissolved organic matter (DOM). Due to limited information about the characteristics of the DOM regarding source, molecular size/weight and diagenetic state, we aimed to performed an optical DOM characterization of 12 temporary wetlands located in the Argentinean Patagonia. As a result, we found that wetlands located in the austral forest have variable amount of dissolved organic carbon (DOC), ranging from 26.04 to 0.9 mg L−1 in a strong longitudinal gradient from west to east, respectively. The proxy for terrestrial input (a350:DOC) showed high values suggesting an allochthonous origin of the DOM. The DOM molecular size (S275–275) showed that most of the wetlands were characterized by high molecular size/weight DOM. A multivariate analysis (RDA) ordinated the wetlands according to their longitudinal position, in which samples collected at west were characterized by high aromaticity and humification, and low recently produced DOM (low BIX). Meanwhile, at eastern side wetlands are characterized by low DOC, low humic DOM components but increasing values of recently produce DOM (high BIX). This study contributes to understand the interaction between terrestrial and aquatic systems in a pristine region which is increasingly impacted by global climate change. [ABSTRACT FROM AUTHOR]

Global carbon dioxide (CO2) evasion from inland waters (rivers, lakes, and reservoirs) and carbon (C) export from land to oceans constitute critical terms in the global C budget. However, the magnitudes, spatiotemporal patterns, and underlying mechanisms of these fluxes are poorly constrained. Here, we used a coupled terrestrial–aquatic model to assess how multiple changes in climate, land use, atmospheric CO2 concentration, nitrogen (N) deposition, N fertilizer and manure applications have affected global CO2 evasion and riverine C export along the terrestrial‐aquatic continuum. We estimate that terrestrial C loadings, riverine C export, and CO2 evasion in the preindustrial period (1800s) were 1,820 ± 507 (mean ± standard deviation), 765 ± 132, and 841 ± 190 Tg C yr−1, respectively. During 1800–2019, multifactorial global changes caused an increase of 25% (461 Tg C yr−1) in terrestrial C loadings, reaching 2,281 Tg C yr−1 in the 2010s, with 23% (104 Tg C yr−1) of this increase exported to the ocean and 59% (273 Tg C yr−1) being emitted to the atmosphere. Our results showed that global inland water recycles and exports nearly half of the net land C sink into the atmosphere and oceans, highlighting the important role of inland waters in the global C balance, an amount that should be taken into account in future C budgets. Our analysis supports the view that a major feature of the global C cycle–the transfer from land to ocean–has undergone a dramatic change over the last two centuries as a result of human activities. Plain Language Summary: Despite occupying only 1% of the Earth's surface, inland waters (rivers, lakes, and reservoirs) play a critical role in global carbon (C) cycling by linking two of the Earth's largest C pools, terrestrial and marine ecosystems, as well as by exchanging CO2 with the atmosphere. Inland waters emit and bury C before it reaches the oceans, with important implications for the global C budget. Although global estimates of lateral C fluxes have been made previously, much uncertainty exists in their magnitudes, spatiotemporal patterns, and underlying controls (anthropogenic vs. natural processes). By improving a coupled terrestrial–aquatic model, we assess how climate, land use, atmospheric CO2, and nitrogen enrichment affected global CO2 evasion and riverine C export along the terrestrial–aquatic continuum since the 1800s. We estimate a 25% increase in terrestrial C loading since the 1800s, of which 59% was emitted to the atmosphere and 23% was exported to the ocean. The increased riverine C exports were primarily due to increasing atmospheric CO2 level and nitrogen inputs; additionally, climate and land conversion dominated interannual and decadal variations in CO2 evasion. Our findings indicate that anthropogenic‐induced climate change and multiple environmental stresses since the preindustrial era have resulted in significant increases in terrestrial C export to oceans and CO2 evasion. Global inland water recycles and exports nearly half of the net land C sink into the atmosphere and ocean, underscoring the importance of inland waters for closing the global carbon budget. Key Points: Terrestrial carbon loading since 1800 has increased by 25%, with 23% of this increase exported to the ocean and 59% being emitted to the atmosphereAtmospheric CO2 and N inputs dominated C export increase, while the climate and land use change dominated the decadal variations in CO2 evasionGlobal inland water recycles and exports nearly half of the net land C sink into the atmosphere and oceans in the 2010s [ABSTRACT FROM AUTHOR]

Introduction: Worldwide, six genera of the class Hydrozoa are recognized in continental waters: the cosmopolitan Hydra, the colonial Cordylophora and Pachycordyle, the medusae Craspedacusta and Limnocnida and the little polyp Calpasoma. Even though interest in cnidarians has grown in recent years, those restricted to freshwater continue to be relegated and there is even little published information on the ubiquity of certain species. In the Neotropical region, knowledge about its distribution is still very scarce. Methods: We reviewed the global literature on the subject and different online database platforms, presenting in this work a nomenclator, including discussions of the status of some species and provide the most recent identification key. Results: This analysis reveals that in 15 countries corresponding to the Neotropical region, the finding of freshwater hydrozoans has been reported. Panama, Brazil and Argentina are the countries with the highest number of reports. Conclusions: The heterogenity of environments where these genera have been found (from the Strait of Magellan to Mexico) offers a clear vision of their wide distribution and great adaptability to different environments. This study evidence the knowledge gap that still exists about the Neotropical freshwater hidrozoans and the importance of systematizing the current information about their distribution, biology and ecology, especially for those species considered invasive. [ABSTRACT FROM AUTHOR]

Regulated water bodies like lakes and reservoirs are increasingly becoming an object of attention due to the problems of greenhouse gas emissions, regional ecology, and the necessity to ensure safe environmental management. However, for some local tasks, it is important to assess the contribution of a hydroelectric power plant (HPP) to various parameters of the nearest water environment, for example, mortality of zooplankton, transfer of suspended matter and phytoplankton, formation of secondary deposits, methane emissions, spatial features of stratification, etc. An example of such studies is the present paper. It is based on unique data of complex measurements of hydrophysical, hydrooptical, hydrobiological, and hydrochemical water parameters, as well as methane fluxes, that were collected at the Gorky Reservoir nearby a HPP in the spring, summer, and autumn of 2022. Preliminary correlations between these parameters were obtained. The results are useful for the correct interpretation of satellite images of inland waters, quantitative description of HPPs' influence on the water environment, knowledge of the main patterns of transformation of aquatic organism communities under conditions of runoff regulation, determination of water quality by hydrobiological parameters, development of mechanisms for improving the ecological state of water bodies, and accounting spatial heterogeneity of methane flows from the surface of the reservoir. [ABSTRACT FROM AUTHOR]

Pollution by synthetic polymers is even more problematic to the environment when this material is fragmented into small portions, forming microplastics (MPs). We analyzed the contamination of ichthyofauna by MPs in an important river of the Atlantic Rainforest in regard to abundance, diversity of morphotypes, polymers, colors, and sizes of the synthetic particles in 20 species of fish. Fish were collected in November 2019 and in March 2020 in five sites along the Pomba River. Of the 101 fish analyzed, 49 (49%) presented MPs in at least one organ. Of the 20 species of fish collected 13 included individuals with at least one MP in their analyzed organs. The organs, trophic categories and feeding areas did not affect the general abundance of MPs types. Blue MPs were predominant, followed by the colors black, red, and white. MP fibers represented 91% of total MPs. Most MPs were between 2 and 3 mm in size. Polyethylene terephthalate (PET), polypropylene (PP), polyamide (PA), polyvinylidene chloride "Nylon" (PVDC), and high-density polyethylene (HDPE) were detected in the fishes. The exposure of the fish species to MPs was associated mainly with individual size and species-specific aspects, regardless of ecological traits. Considering that 55% of the fish species studied are consumed by humans, it is necessary to study the potential impact of MP ingestion on human health and to understand to what extent we may be consuming both plastic particles and contaminants that are adsorbed to MPs. [ABSTRACT FROM AUTHOR]

Abstract Inland waters are significant, yet highly uncertain, natural sources of nitrous oxide (N2O). Many emission models assume that N2O is only emitted from freshwaters, and that N2O sink behavior is negligible. However, observational studies have reported N2O undersaturation, suggesting that inland waters can act as N2O sinks due to net N2O consumption. This study leverages data from the National Ecological Observatory Network (NEON) and an existing global emission model to examine the prevalence of and controls on N2O undersaturation in streams, rivers, and lakes across scales and biomes. We find that N2O undersaturation is prevalent in the NEON data set (14%–30% of samples) and process‐based model outputs (38%), occurring across biomes and spatial scales. Failing to account for undersaturation in the NEON data set could result in an 100% overestimation of N2O emissions. These results show that consideration of N2O sink behavior is needed for accurate emission estimates.

In recent decades, phytoplankton proliferation and sediment input to rivers (especially urban rivers) have become more dramatic under the compound pressure of climate change and human activities. Given the generally narrow width of rivers and current high spatial resolution satellites, which are limited by band settings, bandwidth, and the signal-to-noise ratio, UAVs with their exceptional spatiotemporal resolution can be used as a useful tool for river environmental monitoring and inversion uncertainty assessment. In this study, UAV-based hyperspectral (X20P) and multispectral (P4M) images, along with Sentinel-2 MultiSpectral Instrument (MSI), Landsat-8 Operational Land Imager (OLI) and Landsat-9 OLI2 data, were used to assess the uncertainty in retrieving chlorophyll-a (Chla) and suspended sediment (SS) concentrations in rivers. Chla and SS models based on UAV and satellite data were constructed using stepwise multiple regression and typical Chla and SS retrieval algorithms, respectively, and the performance of the models was the focus of our research. The results demonstrated that in the Chla concentration inversion, each sensor performed as follows: X20P > P4M > Landsat9 OLI2 > Sentinel-2 MSI > Landsat8 OLI, and the performance in the SS concentration inversion was as follows: X20P > Sentinel-2 MSI > P4M > Landsat9 OLI2 > Landsat8 OLI. In addition, the uncertainty of high spatial resolution satellite retrievals was analyzed with the assistance of the UAV-based model. Results showed that narrow bandwidths and finely tuned band settings are more essential for the Chla inversion. The typical Chla retrieval algorithm, NDCI, is only effective in certain bands (band 1 from 684 to 724 nm and band 2 from 660 to 680 nm). It is also noted that Landsat8 and Landsat9 lack some key band settings (e.g., the red-edge band of 700–710 nm), severely limiting practical application in relation to Chla. However, specific variances in different sensor bands have a relatively small impact on SS inversion, for example, the correlation between SS and the R/B (a typical SS retrieval algorithm) constructed by each sensor ranged from 0.68 to 0.77. Chla monitoring, on the other hand, necessitates a higher spatial resolution than SS monitoring. The accuracy decreased markedly when UAV images were resampled to 10 m and 30 m spatial resolution. However, it is not as crucial for the SS inversion, images with the original spatial resolution (RMSE

The Pomeranian lakes in Northern Poland and the nearby coastal waters of the Baltic Sea belong to optically complex water bodies characterised by high eutrophication levels. These water types require a local approach when developing bio-optical algorithms that combine the inherent and the apparent properties of seawater. Well-established local algorithms are of great value for understanding and addressing rapid changes in water quality related mostly to human activities in coastal and near-shore zones, as well as in optically similar lakes. Our research analyses the possibility of using the multi-parameter algorithms of absorption a(λ), backscattering bb(λ) and remote sensing reflectance Rrs(λ), originally developed for the coastal waters of the Southern Baltic Sea, for three selected Pomeranian lakes. Our multi-parameter algorithms are based on the input concentrations of the biogeochemical components measured in the lake waters, i.e., chlorophyll a (Chl a), suspended particulate matter (SPM), inorganic suspended particulate matter (SPMinorg), the sum of the surface concentrations of accessory pigments (ΣC) and coloured dissolved organic matter with a wavelength of 400 nm (aCDOM(400)). Rrs(λ) and a(λ) output values were compared with independent measurements of these parameters conducted in the lake waters at 20 sampling stations. Our algorithm output values of bb(λ) were compared to the values obtained based on the algorithm provided by Ficek, previously developed and validated for Pomeranian lakes, at the same stations. The statistical analyses conducted afterwards showed that the multi-parameter algorithms of Rrs(λ) and a(λ) for the Southern Baltic Sea are sufficient to be used for the stations investigated in the aforementioned three lakes. Specifically, the correlations between the bb(λ) values obtained based on the Ficek algorithm and the bb(λ) values obtained using our multi-parameter algorithm reveal a statistical error rate of less than 20%. [ABSTRACT FROM AUTHOR]

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Harmful and nuisance algal blooms are becoming a greater concern to public health, riverine ecosystems, and recreational uses of inland waterways. Algal bloom proliferation has increased in the Upper Clark Fork River due to a combination of warming water temperatures, naturally high phosphorus levels, and an influx of nitrogen from various sources. To improve understanding of bloom dynamics and how they affect water quality, often measured as algal biomass measured through pigment standing crops, a UAV-based hyperspectral imaging system was deployed to monitor several locations along the Upper Clark Fork River in western Montana. Image data were collected across the spectral range of 400–1000 nm with 2.1 nm spectral resolution during two field sampling campaigns in 2021. Included are methods to estimate chl a and phycocyanin standing crops using regression analysis of salient wavelength bands, before and after separating the pigments according to their growth form. Estimates of chl a and phycocyanin standing crops generated through a linear regression analysis are compared to in situ data, resulting in a maximum R 2 of 0.96 for estimating fila/epip chl-a and 0.94 when estimating epiphytic phycocyanin. Estimates of pigment standing crops from total abundance, epiphytic, and the sum of filamentous and epiphytic sources are also included, resulting in a promising method for remotely estimating algal standing crops. This method addresses the shortcomings of current monitoring techniques, which are limited in spatial and temporal scale, by proposing a method for rapid collection of high-spatial-resolution pigment abundance estimates. [ABSTRACT FROM AUTHOR]