Management Of Aquatic Ecosystems Research Articles

Combined exposure to hypoxia and nanoplastics leads to negative synergistic oxidative stress-mediated effects in the water flea Daphnia magna

In this study, we investigated the combined effects of hypoxia and NPs on the water flea Daphnia magna, a keystone species in freshwater environments. To measure and understand the oxidative stress responses, we used acute toxicity tests, fluorescence microscopy, enzymatic assays, Western blot analyses, and Ingenuity Pathway Analysis. Our findings demonstrate that hypoxia and NPs exhibit a negative synergy that increases oxidative stress, as indicated by heightened levels of reactive oxygen species and antioxidant enzyme activity. These effects lead to more severe reproductive and growth impairments in D. magna compared to a single-stressor exposure. In this work, molecular investigations revealed complex pathway activations involving HIF-1α, NF-κB, and mitogen-activated protein kinase, illustrating the intricate molecular dynamics that can occur in combined stress conditions. The results underscore the amplified physiological impacts of combined environmental stressors and highlight the need for integrated strategies in the management of aquatic ecosystems.

Analysis of dissolved oxygen influencing factors and concentration prediction using input variable selection technique: A hybrid machine learning approach

Accurate quantification of dissolved oxygen (DO) is critically important for the protection and management of aquatic ecosystems. Successful applications have utilized mechanistic and data-driven models to simulate DO content in aquatic ecosystems. However, mechanistic models present challenges due to their complex and difficult-to-solve conditions, making them less portable. Additionally, data-driven model predictions are hindered by the challenge of numerous input variables, impacting both the running speed and prediction performance of the model. To address these challenges, water quality data and meteorological data of the Tanjiang River were obtained. The maximum information coefficient (MIC) input variable selection technique was employed to identify primary environmental factors influencing DO changes. Furthermore, coupled with support vector regression (SVR), two models (SVR and MIC-SVR) were employed to estimate the DO concentration of the Tanjiang River, and the optimal model was established. The results indicated a shift in the primary pollution factor from ammonia nitrogen to total phosphorus after recent treatment in the Tanjiang River. In comparison with the SVR model, the root mean square error (RMSE) of the MIC-SVR model was reduced by 4.46%, and the Nash-efficiency coefficient (NSE) was improved by 45.85%. In addition, study of kernel function selection revealed that considering as many kernel functions as possible is necessary for improving the performance of the SVR model. Conclusively, the proposed MIC-SVR model serves as an effective tool to analyze the relationship between DO and environmental factors, identifying the primary causes of low DO, and accurately predict the DO concentration in the Tanjiang River (especially in its middle and lower reaches), thus providing a reference for governmental decision-making on water environmental protection and water resource management.

Fishes move to transient local refuges, not persistent landscape refuges during river drying experiment

Abstract Anthropogenically driven flow intermittency is increasing in freshwater streams, with important implications for the management and conservation of aquatic ecosystems. Because most freshwater fishes are mobile, they are expected to emigrate from intermittent reaches, but this may not be true in streams transitioning from perennial to intermittent. Here, we attempt to determine if riverine fishes vacate drying reaches before intermittency or remain in local refuges. We implemented a controlled, in situ experimental flow reduction resulting in intermittency, reducing flows from ~1.0 to 0 m3/s over a 3‐week period. We monitored fish and fish‐habitat changes over a 5‐week period before, during and after flow reductions. During flow reductions, total wetted habitat was ultimately reduced by 91%. Habitat loss over time was not equal among habitat types: pool habitat increased slightly as run habit was lost, and backwater and isolated pool habitats were not strongly related to discharge. Likewise, water depth in run habitats decreased faster than other habitats. Only the river carpsucker Carpiodes carpio appeared to move upstream during flow recession; seven other species remained within drying sites. Habitat loss negatively affected fish populations, but at a lower rate than that at which habitat was lost, until sites dried completely. Overall, two species, red shiner Cyprinella lutrensis and western mosquitofish Gambusia affinis, had increased population growth during the study, whereas the remaining species had population declines. Fishes were able to find transient local refuges during flow reductions but did not vacate sites before intermittent conditions. Accounting for lack of emigration from anthropogenic flow‐intermittent reaches will be important for designing conservation actions for fishes threatened by increasing flow intermittency. Creation of refuge habitats may not be effective for widely dispersed species that do not actively seek refuge habitats, unless those habitats support enough individuals to maintain resilience following the intermittent conditions.

Advances in environmental DNA monitoring: standardization, automation, and emerging technologies in aquatic ecosystems.

Environmental DNA (eDNA) monitoring, a rapidly advancing technique for assessing biodiversity and ecosystem health, offers a noninvasive approach for detecting and quantifying species from various environmental samples. In this review, a comprehensive overview of current eDNA collection and detection technologies is provided, emphasizing the necessity for standardization and automation in aquatic ecological monitoring. Furthermore, the intricacies of water bodies, from streams to the deep sea, and the associated challenges they pose for eDNA capture and analysis are explored. The paper delineates three primary eDNA survey methods, namely, bringing back water, bringing back filters, and bringing back data, each with specific advantages and constraints in terms of labor, transport, and data acquisition. Additionally, innovations in eDNA sampling equipment, including autonomous drones, subsurface samplers, and in-situ filtration devices, and their applications in monitoring diverse taxa are discussed. Moreover, recent advancements in species-specific detection and eDNA metabarcoding are addressed, highlighting the integration of novel techniques such as CRISPR-Cas and nanopore sequencing that enable precise and rapid detection of biodiversity. The implications of environmental RNA and epigenetic modifications are considered for future applications in providing nuanced ecological data. Lastly, the review stresses the critical role of standardization and automation in enhancing data consistency and comparability for robust long-term biomonitoring. We propose that the amalgamation of these technologies represents a paradigm shift in ecological monitoring, aligning with the urgent call for biodiversity conservation and sustainable management of aquatic ecosystems.

Combined effects of spinetoram and Microcystis aeruginosa on Daphnia pulex offspring: Maternal effects and multigenerational implications

The increasing occurrence of harmful algal blooms (HABs) in freshwater ecosystems detrimentally affect global water environments. Zooplankton's role in controlling HABs is hindered by contaminant exposure, necessitating research into combined stressors' ecological impacts. The response of Daphnia, a freshwater keystone species, to environmental stressors can be influenced by its maternal effects. Here, we investigated the combined effects of the world-widely used insecticide spinetoram and non-toxic HABs species Microcystis aeruginosa on the life-history traits of D. pulex offspring produced from different maternal food conditions. Four maternal groups were established, with each group receiving a specific blend of C. vulgaris (Ch) and M. aeruginosa (Ma) in varying proportions: A (100% Ch), B (90% Ch + 10% Ma), C (80% Ch + 20% Ma), and D (70% Ch + 30% Ma). The offspring from the third brood were gathered, and a 21-day experiment was carried out, involving various feeding groups (AA, AD, BA, BB, CA, CC, DA, and DD). Results demonstrated that grazing on M. aeruginosa by D. pulex induced maternal effects on their offspring, with the continuous exposure group showing an enhanced tolerance to M. aeruginosa. This study also unveiled that spinetoram could interfere with the molting of D. pulex, leading to developmental retardation. The Recovery Group exhibited an intriguing phenomenon: under the influence of both concentrations of the pesticide spinetoram (0.18, 0.35 μg L−1), D. pulex produced more offspring. This might be due to a combined strategy of allocating more energy towards reproduction in response to low-quality food and a potential hormetic effect from low concentrations of spinetoram. Assessing the interplay of combined stressors across multiple generations, encompassing harmful algal blooms (HABs) and environmental pollutants, is essential for predicting population responses to evolving environmental conditions. This understanding is vital for the protection and management of aquatic environments and ecosystems.

Phytoplankton Community Dynamics in Ponds with Diverse Biomanipulation Approaches

The rising challenge of eutrophication in aquatic systems globally necessitates an understanding of phytoplankton community dynamics under diverse biomanipulation approaches. This study, conducted from June 2022 to July 2023 in the Yuqiao Reservoir’s ponds in China, explored phytoplankton dynamics across ponds under different biomanipulation strategies. The study included a pond (BL) without fish stocking, a pond (CH) stocked with carnivorous and herbivorous fish, and another pond (CFD) incorporating a mix of carnivorous, filter-feeding, and detritus-feeding fish. Substantial seasonal variations in phytoplankton density and biomass were observed. In the BL pond, phytoplankton density ranged from 0.23 × 107 to 3.21 × 107 ind/L and biomass from 0.71 to 7.10 mg/L, with cyanobacteria predominantly in warmer seasons and a shift to cryptophytes and chrysophytes in winter. The CH pond exhibited a density range from 0.61 × 107 to 8.04 × 107 ind/L and biomass of 1.11 to 7.58 mg/L. Remarkably, the CFD pond demonstrated a significant reduction in both density (0.11 × 107 to 2.36 × 107 ind/L) and biomass (0.27 to 5.95 mg/L), indicating the effective implementation of its biomanipulation strategy. Key environmental factors including total nitrogen, water temperature, pH, chlorophyll-a, and total phosphorus played a significant role in shaping phytoplankton communities. The study highlights the importance of tailored biomanipulation strategies in aquatic ecosystem management, emphasizing long-term monitoring for sustainable management of eutrophication.

One- and Three-Dimensional Hydrodynamic, Water Temperature, and Dissolved Oxygen Modeling Comparison

Understanding and modeling water quality in a lake/reservoir is important to the effective management of aquatic ecosystems. The advantages and disadvantages of different water quality models make it challenging to choose the most suitable model; however, direct comparison of 1-D and 3-D models for lake water quality modeling can reveal their relative performance and enable modelers and lake managers to make informed decisions. In this study, we compared the 1-D model MINLAKE and the 3-D model EFDC+ for water temperature, ice cover, and dissolved oxygen (DO) simulation in three Minnesota lakes (50-m Carlos Lake, 23.5-m Trout Lake, and 5.6-m Pearl Lake). EFDC+ performed well for water temperature and DO simulation in the open water seasons with an average root mean square error (RMSE) of 1.32 °C and 1.48 mg/L, respectively. After analyzing the ice thickness with relevant data, it was found that EFDC+ calculates a shorter ice cover period and smaller ice thickness. EFDC+ does not consider snowfall for ice thickness simulation. The results also revealed that EFDC+ considers spatial variance and allows the user to select inflow/outflow locations precisely. This is important for large lakes with complex bathymetry or lakes having multiple inlets and outlets. MINLAKE is computationally less intensive than EFDC+, allowing rapid simulation of water quality parameters over many years under a variety of climate scenarios.

Three-dimensional augmentation for hyperspectral image data of water quality: An Integrated approach using machine learning and numerical models

This research introduces a comprehensive methodology to enhance hyperspectral image data (HSD) utility, specifically focusing on the three-dimensional (3-D) augmentation of Chlorophyll-a (Chl-a). This study comprises three significant steps: (1) the augmentation of limited field water quality data in terms of time interval and number of variables using neural network models, (2) the generation of 3-D data using numerical models, and (3) the extension of the hyperspectral image data into 3-D data using machine learning models. In the first phase, Multilayer Perceptron (MLP) models were developed to train water quality interactions and successfully generated high-frequency water quality data by adjusting biased measurements and predicting detailed water quality variables. In the second phase, high-frequency data generated by MLP models were applied to develop two numerical models. These numerical models successfully generated 3-D data, thereby demonstrating the effectiveness of integrating numerical modeling with neural networks. In the final phase, ten machine learning models were trained to generate 3-D Chl-a data from HSD. Notably, the Gaussian Process Regression model exhibited superior performance, effectively estimating 3-D Chl-a data with robust accuracy, as evidenced by an R-square value of 0.99. The findings align with theories of algal bloom dynamics, further validating the effectiveness of the approach. This study demonstrated the successful integrated development for HSD extension using machine learning models, numerical models, and original HSD, highlighting the potential of such integrated methodologies in advancing water quality monitoring and estimation. Notably, the approach leverages readily accessible data, allowing for the swift generation of results and bypassing time-consuming data collection processes. This research marks a significant step towards more robust, comprehensive water quality monitoring and prediction, thereby facilitating better management of aquatic ecosystems.

Integration of social and cultural dimensions in the assessment of environmental flows: case of the Ouémé delta in West Africa

The use of environmental flows as a technique for the diagnosis and sustainable management of aquatic ecosystems in West Africa is relatively new and cautious, despite being broadly implemented for many years in Western countries and Southern Africa. The present study, the first to evaluate the environmental flows in Benin, concentrates on the deltaic region of the Ouémé River. The assessment utilises the Building Block Methodology approach, and incorporates ecological, socio-cultural, and religious dimensions. The assessment focuses on the alterations in river flows and the impact on local communities’ livelihoods, beliefs, and cultural and religious practices. The results indicate that the population of the Ouémé Delta are significantly impacted by changes in the river’s flow. Indeed, floods play a crucial role in people’s daily routines and livelihoods, while a significant decrease in river flow results in economic instability. Moreover, there is a strong link between specific religious customs in the area and the river’s flow. To maintain the current provisioning, regulating, and cultural ecosystem services in the Ouémé delta, The study recommended to allocate 100% of the River Ouémé’s natural flow during low-water periods (December to May) and 50% of the natural flow during high-water periods (June to November). This allocation ensures that the environment’s water needs are met and will contribute to preserve the Ouémé delta’s ecosystem, ensuring the sustainability of its ecological habitats and biodiversity. However, the implementation of these recommendations would require more debate and a real consensus on the priority between development and environment.

A preliminary random checklist of benthic organisms in selected lakes of west peninsular Malaysia

The freshwater ecosystem (Kelana Jaya Lake, Seremban Lake Garden and Kanching Eco Forest Park) of west Peninsular Malaysia was the focus of the study's attempt to offer a current checklist of benthic organisms. Three benthic organisms were identified in the urbanized Kelana Jaya Lake, namely the red-rim melania (Melanoides tuberculata), apple snail (Pomacea sp.), and an Odonata damselfly nymph. Four different species were identified for Seremban Lake Garden: Hydrilla verticillata, Viviparus sp., nymph of Odonata, and Macrobrachium sp. The freshwater prawn Macrobrachium was the only genus identified for Kanching Eco Forest Park. Our attempts to promote aquatic ecosystem management and conservation in Malaysia can use the checklist of benthic creatures from the freshwater ecosystems as a continuous baseline for future reference.

Utilizing Machine Learning within Artificial Intelligence to Enhance Dissolved Oxygen Estimation in the Mississippi River via Temperature-Driven Polynomial Regression

Abstract: In this research, a comprehensive examination of Dissolved Oxygen (DO) levels in the Mississippi River is undertaken, employing a Polynomial Regression model drivenby temperature data for predictive estimation. Dissolved oxygen serves as a pivotal indicator of water quality and the health of aquatic ecosystems, making its accurate forecasting crucial for effective environmental monitoring and management. By utilizingtemperature as a primary predictor, this study seeks to advance our understanding of the intricate relationship between temper- ature and DO within the context of the Mississippi River. The research involves an extensive dataset comprising measurements of water temperature and dissolved oxygen collected over an extended duration. A Polynomial Regression model is employed to establish a mathematical link between temperature and DO, thus providing a predictive tool for estimating DO levels at specific locations along the river. The model’s performance is subjected to a rigorous evaluation, involving the assessment of diverse statistical metrics and validation techniques. The research outcomes yield valuable insights into the dynamics of DO in the Mississippi River, emphasizing the pivotal role of temperature as a primary driver of DO fluctuations. This study introduces a practical and efficient method for the monitoring and prediction of DO levels, which can be instrumental in the preservation and sustainable management of this vital aquatic ecosystem. Moreover, it makes a meaningful contribution to the broader realm of water quality assessment and has the potential to inform policies and practices aimed at ensuring the environmental well- being of the Mississippi River.

Century-Scale Environmental Evolution of a Typical Subtropical Reservoir in the Guangdong–Hong Kong–Macao Greater Bay Area

As one of the world’s four Greater Bay Areas, the Guangdong–Hong Kong–Macao Greater Bay Area (GBA) faces many environmental challenges along with rapid economic development, causing significant degradation of aquatic ecosystems. However, there is limited knowledge on long-term environmental changes (i.e., >50 years), and restoration of the degraded aquatic ecosystems in the GBA has become increasingly difficult. This study selects a typical inland water body, the Miaotan Reservoir, from Huizhou City in the GBA, to explore long-term changes in water and the eco-environment over the past 70 years and to provide some restoration and management strategies for degrading aquatic ecosystems in the region. We collected a sediment core from the reservoir center and established an age–depth profile by integrating 210Pb and 137Cs dating. We then set up high-resolution diatom community succession stratigraphy and multiple indicators (grain size, element, geochemical and social indicators) as responses to environmental changes in the reservoir. Our results show that significant changes have occurred in the ecosystem and environment of the Miaotan Reservoir and its catchment over the past 70 years. The diatom community underwent a gradual transition from absolute dominance of the mesotrophic species Aulacoseira granulata to dominance of the eutrophic species Nicizschia gracilis, Nicizschia palea and Achanathes sp., indicating the onset of water quality degradation and ecosystem changes in the 1990s due to eutrophication. The RDA (Redundancy analysis) results demonstrate that exogenous pollutant inputs into the Miaotan Reservoir resulting from agricultural activities over the period led to serious environmental changes, e.g., toxic algal bloom and heavy metal pollution. This study enriches our understanding of long-term environmental changes in inland lakes and reservoirs in South China and provides insights into the restoration and management of aquatic ecosystems in the GBA.

Spatio-temporal dynamics of phytoplankton in a diversion reservoir and the major influencing factors: taxonomic versus functional groups classification.

Identifying factors affecting phytoplankton dynamics is crucial to the management of aquatic ecosystems. A lot of scholars have conducted intensive studies on phytoplankton in lake or reservoirs, but not many studies have been conducted on diversion reservoirs. To explore the seasonal and spatial variation of phytoplankton communities and their relationship with environmental factors in the context of water diversion, a case study was carried out at XiKeng (XK) reservoir in South China. In this study, month-by-month water samples and phytoplankton were collected from this reservoir from December, 2021, to July, 2022. The results showed that the phytoplankton community was characterized by significant spatial and temporal variations. There were significant differences in phytoplankton abundance and structure in the reservoirs in terms of time. The abundance of phytoplankton cells and the proportion of Cyanobacteria in the reservoir showed a trend of increasing from autumn to spring and then decreasing from spring to summer, while the functional group evolved from S1 in autumn to SN in spring and summer. The abundance of phytoplankton was influenced by the dynamic water division and the characteristics of the reservoir itself, resulting in a spatial distribution characteristic of AIII > AII > AI. Water temperature (WT) and nutrients were the key factors driving the changes in phytoplankton abundance and community structure in the reservoir. These findings will deepen our understanding of the spatial and temporal dynamics of phytoplankton community structure in diversion reservoirs and provide a basis for freshwater water ecological management strategies.

Nature reserves (zapovedniks) in the Volga catchment: protection, research and management

AbstractIn the Russian Federation, the protection category “Zapovednik” represents a strictly protected area, where the access is restricted and the aim is to keep the area “forever wild”. We provide an overview about the organization of these nature reserves and highlight their contribution to fundamental research. Aquatic ecosystems in zapovedniks provide pristine sites of great importance for long-term monitoring and research, which fosters process understanding regarding interannual variability and development of aquatic coenosis. We present a long term monitoring and research project about abiotic and biotic parameters in the Central Forest State Nature Biosphere Reserve. Examples from the Privolzhskaya Lesostep Nature Reserve include monitoring of invasive fish as well as analyses about the influence of beavers on fish. The Astrakhan Biosphere Nature Reserve in the Volga delta is a hotspot for fish biodiversity; thus, there the state nature reserve security service plays an important role to avoid poaching. Our case studies from the Volga Basin exemplify the structure and function of nature reserves and highlight their contribution to research, protection and management of aquatic ecosystems. Long-term datasets from the zapovedniks can (i) improve process understanding, (ii) ensure protection of aquatic systems and sustainable water management and (iii) support knowledge-based decisions.

COVID-19 impacts on the water quality of aquatic environment in the Indian Ocean Rim region

COVID-19 pandemic has demonstrated bidirectional influence of human intervention on water bodies. In the present study, the Web of Science Core Collection (WoSCC) database was used to selectively extract the publications related to water quality and aquatic environment in the IOR region impacted by COVID-19 pandemic between the year of 2019 and 2022. Among the 9 document clusters generated, 4 were associated with impacts of COVID-19 towards the environment, and 5 with COVID-19 epidemiology in wastewater. The objective of the present study is to investigate the implications of lockdowns due to COVID-19 pandemic on the water quality of aquatic environment in the IOR region through literature search and scientometric analysis. The findings of this first scientometric study in the IOR region may help to improve the regional management of aquatic resources and ecosystem by clarifying the association between COVID-19 pandemic and the aquatic environment.

Gene co-expression networks unravel the molecular responses of freshwater hydrophytes to combined stress of salinity and cadmium

Salinization in freshwater lakes is becoming a serious global environmental problem, especially in lakes of plateaus such as south-western plateau of China. However, limited information is available about the molecular response of freshwater hydrophytes to salinity under multiple stress. In the present study, a weighted gene co-expression network (WGCNA) was used to identify the modules of co-expressed genes in the physiological and biochemical indicators of Pistia stratiotes to determine its molecular response to salinity (NaCl) alone and when combined with cadmium (Cd). The physiological and biochemical indicators showed that P. stratiotes improved its salt tolerance by enhancing photosynthetic abilities, reducing oxidative stress, and inducing osmoprotectant generation. Morever, addition of NaCl reduced the Cd accumulation in P. stratiotes. Transcriptome and WGCNA analysis revealed that the pathways of alpha-linolenic acid metabolism, ribosomal, flavonoid biosynthesis, and phenylpropanoid biosynthesis were significantly enriched in both treatments. Genes associated with photosynthesis-antenna proteins, nitrogen metabolism, and the acid cycle pathways were only expressed under salinity stress alone, while the proteasome pathway was only significantly enriched in the combined salinity and Cd treatment. Our findings provide novel insights into the effects of salinization on aquatic plants in freshwater ecosystems and the management of aquatic ecosystems under global change.

Driving forces of hydrological health and multifractal response of fish habitat in regulated rivers

Climate change and anthropogenic activities are major influences on the hydrological cycle, further altering river hydrological health. However, the characteristics of the forces in driving the variations of hydrological health at long-short time scales (annual, seasonal, monthly), as well as the potential impacts of these variations on aquatic habitats, remain unclear. In this study, the flow threshold method was introduced to identify the inherent characteristics of river hydrological health degree (RHD) evolution in the upper reaches of the Yangtze River (URYR) through the extreme-point symmetric modal decomposition (ESMD) method and range of variation approach (RVA). The RHD under unregulated conditions was reconstructed to quantify the impacts of anthropogenic activities and climate change. Subsequently, a multifractal model was proposed to establish the relationship between RHD and habitat-weighted usage area (WUA) during the spawning period of the Four Famous Major Carps, aiming to analyze the response mechanisms of habitat conditions to RHD fluctuations. The results showed that the RHD in the URYR exhibited degradation characteristics, experiencing a moderate change with a value of 0.44. Climate change was identified as the dominant factor causing the annual-scale decline in RHD, with an average impact weight of 62.9%. At the annual scale, Anthropogenic activities exacerbate (−3.4), counteract (20.1), and counteract (20.5) the adverse climatic impacts at Yichang, Cuntan, and Zhutuo stations, respectively. Additionally, the effect of human activities during the flood season is slight, with the most favorable and unfavorable impacts occurring in December (50.7) at the Zhutuo station and in October (−27.2) at the Yichang station. Under the influence of driving forces, the multifractal correlation of the RHD-WUA system tended to homogenized as the time window increased, indicating the presence of potential nonlinear dependence, asymmetric fractal characteristics, and positive-to-negative persistence transitions. Therefore, modeling river health considering fish habitat cannot be limited to linear paradigms. The findings provide valuable insights for the management and restoration of aquatic ecosystems.

Two centuries of changes - revision of the hydrography of the Biebrza Valley, its transformation and probable ecohydrological challenges

Human-induced changes in hydrography have led to serious changes in the hydrological and ecological condition of ecosystems, including habitat fragmentation and reduction of water in the landscape. The aim of this study was to assess the transformation of the hydrographic network in the Biebrza National Park (BbNP) over the XIX-XXI centuries and to analyze its probable ecohydrological challenges. The analysis of changes in the hydrographic network was based on a spatial comparison of hydrographic network elements on the basis of spatial sources. As a result of both natural and human-induced processes, there have been significant changes to elements of the hydrographic network of the BbNP. The length, area and sinuosity of the rivers in the BbNP area have decreased significantly in the XIX-XXI centuries, in contrast to the length of the canals dug in the XIX century - their length increased. On average, river channelization reduced channel water storage capacity by 49%. In other cases the average decrease of storage capacity of the channel was about 14%. As a result of drainage works in the XIX century, the network of drainage ditches was established in the BbNP, which was significantly extended (more than 6 times) in the XXI century. A comprehensive analysis of hydrographic changes, their causes and possible consequences is necessary to understand the dynamics of river networks. It also makes it possible to predict the future ecohydrological response of rivers to anthropogenic influences and climate change, thus helping to establish appropriate management and ecohydrological restoration of aquatic ecosystems.

Movement of Southern European Aquatic Alien Invertebrate Species to the North and South

Due to globalisation and anthropopressure (intensification of shipping, creation of water corridors connecting seas, cultivation of commercial species), the movement of aquatic species has increased in recent years. The determination of trends in the movement of aquatic species in their geographical distribution over time is important because it may help in the management of a species in aquatic ecosystems. There are also knowledge gaps on the long-term trends in the movements of Southern European aquatic alien invertebrates. The study provides the first evidence of both northward and southward movements of these species based on available observations from 1940 to 2021, using meta-analyses and GAM modelling. To date, the majority (98%) of analysed Southern European aquatic alien invertebrates of Mediterranean and Ponto-Caspian origin have moved to the north. Among them, 61% are Ponto-Caspian aquatic alien invertebrates that moved only to the north, and 4% are Mediterranean aquatic alien invertebrates that moved only to the north; the rest include species that moved to the north and south: 27% are Ponto-Caspian aquatic alien invertebrates, and 6% are Mediterranean aquatic alien invertebrates. The one-way movement to the south was observed only in 2% of Mediterranean aquatic alien species. The study will help in understanding the movement patterns of Southern European aquatic alien invertebrates and in the effective management of aquatic ecosystems that allow for the co-existence of people and the rest of biodiversity.

Compact and modular autonomous surface vehicle for water research: The Naval Operating Research Drone Assessing Climate Change (NORDACC)

Research, monitoring, and management of marine and aquatic ecosystems often require surface water samples to measure biogeochemical and optical parameters. Traditional sampling with a boat and several personnel onboard can be labor-intensive and safety requirements limit sampling activities in high-risk environments. This paper describes the Naval Operating Research Drone Assessing Climate Change (NORDACC). NORDACC is an open source, light-weight, and portable autonomous surface vehicle that can acquire surface water samples while also measuring sea surface temperature and salinity for the duration of its deployment. NORDACC is ideal for operations in remote areas where resources and personnel are limited. Two sample bottles, each one liter in volume, can be filled, either at pre-programmed sampling stations or manually, using the remote control. A trimaran design provides buoyancy and stability, with hulls constructed of vacuum-formed acrylonitrile butadiene styrene (ABS) plastic. NORDACC can navigate autonomously between waypoints and features first person view capabilities for enhanced situational awareness. NORDACC’s performance was validated in Aarhus Bay, Denmark, collecting multiple surface water samples in winds in excess of 8 ms−1 and steep, choppy waves.