Monitoring Of Aquatic Ecosystems Research Articles

Optimizing Sampling Strategies for Estimating Riverine Nutrient Loads in the Yiluo River Watershed, China

Accurately estimating nutrient loads is crucial for effective management and monitoring of aquatic ecosystems. This study evaluated the uncertainty in different sampling frequencies and calculation methods for estimating total nitrogen (TN) and total phosphorus (TP) loads in the Yiluo River watershed, a tributary of the Yellow River in China. Using daily TN and TP concentration data from 2019 to 2020, we conducted a bootstrapping analysis to evaluate the accuracy of nine different load estimation methods at different sampling frequencies. Our results showed that Method 3 (M_3, constant concentration interpolation) and Method 7 (M_7, flow-weighted concentration method), when used with a biweekly sampling frequency, had the lowest Standard Deviation of the Percentage errors (STD) (7.70% and 8.60% for TN, 12.0% and 18.8% for TP, respectively) and Mean Relative Error (MRE) values (0.078% and −1.60% for TN, 0.305% and 2.33% for TP, respectively) on an annual scale. For monthly TN and TP load estimates, M_7 can control the MRE within ±20% at a biweekly sampling frequency. Furthermore, the uncertainty in TN and TP load estimates was generally larger during the summer months (June–September), emphasizing the important role of storm events in nutrient export. Extreme events (<10% of the time) contributed approximately 50% of the annual nutrient loads. The findings of this study provide a scientific basis for optimizing water quality monitoring schemes and management strategies in agricultural watersheds.

General System Architecture and COTS Prototyping of an AIoT-Enabled Sailboat for Autonomous Aquatic Ecosystem Monitoring

General System Architecture and COTS Prototyping of an AIoT-Enabled Sailboat for Autonomous Aquatic Ecosystem Monitoring

Microbial Community Colonization Process Unveiled through eDNA-PFU Technology in Mesocosm Ecosystems.

Microbial communities are essential components of aquatic ecosystems and are widely employed for the detection, protection, and restoration of water ecosystems. The polyurethane foam unit (PFU) method, an effective and widely used environmental monitoring technique, has been improved with the eDNA-PFU method, offering efficiency, rapidity, and standardization advantages. This research aimed to explore the colonization process of microbial communities within PFUs using eDNA-PFU technology. To achieve this, we conducted ten-day monitoring and sequencing of microbial communities within PFUs in a stable and controlled artificial aquatic ecosystem, comparing them with water environmental samples (eDNA samples). Results showed 1065 genera in eDNA-PFU and 1059 in eDNA, with eDNA-PFU detecting 99.95% of eDNA-identified species. Additionally, the diversity indices of bacteria and eukaryotes in both methods showed similar trends over time in the colonization process; however, relative abundance differed. We further analyzed the colonization dynamics of microbes in eDNA-PFU and identified four clusters with varying colonization speeds. Notably, we found differences in colonization rates between bacteria and eukaryotes. Furthermore, the Molecular Ecological Networks (MEN) showed that the network in eDNA-PFU was more modular, forming a unique microbial community differentiated from the aquatic environment. In conclusion, this study, using eDNA-PFU, comprehensively explored microbial colonization and interrelationships in a controlled mesocosm system, providing foundational data and reference standards for its application in aquatic ecosystem monitoring and beyond.

Benefits of combined environmental DNA and microscopy for diversity monitoring in rotifer community: A mesocosm experiment

Rotifers are crucial for the monitoring of aquatic ecosystems because of the sensitive response of rotifer community structure to environmental changes. Comparisons and combinations of meta-barcoding (sequence analysis) and traditional morphological identification for rotifer community responses are rare. To better understand the differences between the two approaches, we conducted a study using 48 mesocosms (2500 L) and a combination of warming, nutrient loading, and pesticide to evaluate the applicability of both methods to rotifer communities in order to better understand how rotifer communities respond to multiple environmental stressors. The findings demonstrated that the degree of matching between both techniques was limited, despite the fact that there was a substantial positive association between the morphology abundance determined by morphological identification and the sequence abundances determined by eDNA metabarcoding. Although the two methods had similar responses to various environmental stresses, sequence analysis can identify rotifers that are difficult to identify with traditional methods such as Bdelloidea, while classical morphological methods were more suitable for assessing the effects of various environmental changes on rotifer communities. This study provided valuable implications for monitoring and managing aquatic ecosystems since it enables us to spot changes in the rotifer community structure early on and take the necessary precautions to safeguard these sensitive ecosystems.

Toward phytoplankton parasite detection using autoencoders

Phytoplankton parasites are largely understudied microbial components with a potentially significant ecological influence on phytoplankton bloom dynamics. To better understand the impact of phytoplankton parasites, improved detection methods are needed to integrate phytoplankton parasite interactions into monitoring of aquatic ecosystems. Automated imaging devices commonly produce vast amounts of phytoplankton image data, but the occurrence of anomalous phytoplankton data in such datasets is rare. Thus, we propose an unsupervised anomaly detection system based on the similarity between the original and autoencoder-reconstructed samples. With this approach, we were able to reach an overall F1 score of 0.75 in nine phytoplankton species, which could be further improved by species-specific fine-tuning. The proposed unsupervised approach was further compared with the supervised Faster R-CNN-based object detector. Using this supervised approach and the model trained on plankton species and anomalies, we were able to reach a highest F1 score of 0.86. However, the unsupervised approach is expected to be more universal as it can also detect unknown anomalies and it does not require any annotated anomalous data that may not always be available in sufficient quantities. Although other studies have dealt with plankton anomaly detection in terms of non-plankton particles or air bubble detection, our paper is, according to our best knowledge, the first that focuses on automated anomaly detection considering putative phytoplankton parasites or infections.

Features of the gas chromatographic method for monitoring the content of phenols in an aqueous medium

THE RELEVANCE. Phenols are one of the main pollutants of the aquatic environment and have a harmful effect on the human body. Therefore, their determination today is an urgent problem. The purpose of this work is to determine the content of phenols in an aqueous medium by gas chromatographic method using various sorption materials. To do this, it is necessary to consider some features of the gas chromatographic method for monitoring the content of phenols in an aqueous medium using various sorption materials. Based on a detailed literature review to show that phenols and their derivatives are highly toxic substances, have low values of MPC standards, ha\’e a negative impact on the human body, which necessitates their control in the aquatic environment. METHODS. To determine phenols in an aqueous medium, the experimental part of the work was carried out on a Crystallux-4000M gas-liquid chromatograph with a flame ionization detector and nozzle columns filled with various sorbents, as which polyethylene glvcol-1500, SE-30 and arsenated polyethylene glycol PEG(As) were used. RESULTS. For gas chromatographic separation of phenols and their derivatives, sorption materials of various physicochemical nature were used. It has been established that the most optimal sorbent, which separates almost all phenols and their derivatives, is polyoxyethylene bis arsenate, the molecule of which contains two arsenvl groups capable of intermolecular interactions with the analyzed sorbates. CONCLUSION. An experimental study of the phenol content in an aqueous medium using a gas-liquid chromatograph Crystallux-4000M was carried out. The characteristics of the retention of phenols on sorption materials of different physicochemical nature are determined. It is shown that the most complete separation of the individual components of phenol derivatives is carried out on a sorbent prepared on the basis of polyoxyethylene bis arsenate, which is explained by the presence in the structure of its molecule of non-white electron pairs of oxygen atoms capable of intermolecular interactions with the hydroxyl group of phenols. The linear dependence of the logarithm of the relative volume of phenols on their dipole moments and refractive index is established. A deviation from this dependence is obsen’ed for phenols having functional substituents in the ortho-position of the benzene ring. This can be explained by the electronic effect? which leads to steric difficulties during intermolecular interaction in the sorbent - sorbate system. Based on the theoretical studies carried out, it was possible to completely separate the individual components of phenols, especially those with close boiling points. The obtained data were tested in practice when monitoring the content of phenols in the silt drains of the Volga river. This technique of gas chromatographic analysis can be used in the system of ecological monitoring of aquatic ecosystems.

Shellfish as Biosensors in Online Monitoring of Aquatic Ecosystems: A Review of Russian Studies

The use of biological objects in monitoring the state of the environment and the changes caused by the impact of environmental pollution on marine and fresh waters is a promising tool due to a lower cost in comparison to traditional monitoring and the ability to receive immediate information about the ecosystem status. In this review, we summarize the biological information about shellfish biomonitors and the results of studies focused on the development and use of the bioindicator species in early warning systems in Russia. Since the mid-1980s, Russian specialists have developed online biomonitoring systems; as in the rest of world, there are two main approaches that are currently applied to study the physiological status of potential biosensor shellfish species and to monitor freshwater and marine systems: valvometry (registration of gaping activity in bivalve mollusks) and photoplethysmography (registration of cardiac activity in mollusks and crustaceans). Valve movement responses to stressors such as abnormal conditions and pollutants include the closure of shell valves for a long period, decrease in the average distance between valves, rapid shell opening, and higher closing frequency. Cardiac activity reactions of shellfish to stress factors include rapid increases in heart rate and stress index, higher variability in heart rate than under normal conditions, and longer periods required for heart rate recovery after stress. The most common bioindicators used to monitor environmental disturbances in marine ecosystems are blue mussels, Iceland scallops, and red king crabs in cold-water habitats and Black Sea mussels in warmer waters as well as freshwater mussels and crayfish in fresh waters.

Time-Series Analysis of Oxygen as an Important Environmental Parameter for Monitoring Diversity Hotspot Ecosystems: An Example of a River Sinking into the Karst Underground

Predicting variations in dissolved oxygen concentration (DO) is important for management and environmental monitoring of aquatic ecosystems. Regression analyses and univariate and multivariate time-series analyses based on autoregressive methods were performed to investigate oxygen conditions in the Pivka River, Slovenia. The monitoring site was established upstream where the river sinks into the karst cave Postojnska jama, which hosts one of the richest subterranean faunas yet studied worldwide. It was found that abnormal variations of DO started to be noticeable at values of DO < 3 mg/L and became more pronounced until the ecosystem reached fully anoxic conditions. The abnormal fluctuations during the critical summer period were due to environmental conditions, organic load and resident biota. Predictions for future detection of anomalies in DO values were made from stable residuals of the measured data, and it was demonstrated that the model could be used to obtain a reliable estimate for a short period, such as one day. The example presented an analysis pipeline based on specific and established threshold DO values, and it is particularly important for ecosystems with diversity hotspots where prolonged low DO values can pose a threat to their biota.

A remotely controlled automated field measurement system for light extinction in coastal waters

The Secchi disk depth (SD) is an important parameter in aquatic ecosystem monitoring. As algal growth depends on solar irradiation, the SD - a measure of light extinction - gives an indirect indication of the chlorophyll concentration. However, most SD measurements are manually based and too sparse to resolve water quality variations during algal blooms.A remotely controlled automatic system for field measurement of light extinction has been developed and installed in three marine fish culture zones in Hong Kong. The visual images of the disk at different prescribed depths and the surrounding water are taken. Based on the contrast theory and image analysis, the recorded light intensity distributions can be analyzed to give the SD and the light extinction coefficient. The method has been extensively verified by field data over a wide range of water quality and hydro-meteorological conditions. The proposed system enables high frequency SD measurements on demand for environmental management and emergency response.

Florix, an index to assess plant species in floodplains for nature conservation – Developed and tested along the river Danube

Natural floodplains are ecosystems with a diverse mosaic of habitats and site conditions, but also highly threatened due to anthropogenic pressures. Plant species occur in all habitat types and can indicate their value for nature conservation. To improve sustainable management of rivers and floodplains, several indices such as the River Ecosystem Service Index (RESI) have been developed. However, there are so far no assessment schemes for the entire range of floodplain plants. The common assessment approaches like biological integrity, achievement rates or threatened species (Red list), applying to other species groups or other ecosystems, are not appropriate in floodplains. Legal obligations and the need to restore floodplains clearly call for an index assessing the ecological value in a reference area which can be combined with a 5-scale assessment in accordance to established assessments like RESI or the Water Framework Directive.Five typical characteristics describing vascular plants’ adaptation to floodplain habitats were identified. These can be derived from published data sets available for all species in Germany. We checked these indicators for multicollinearity and selected three of them: species number, hydrodynamic indicators, nature conservation indicators. Species number highly correlate with habitat indicators and geographic occurrence. For the selected three indicators we determined thresholds to group habitats and their indicator rate to five classes (very low to very high value for nature conservation). These thresholds are valid for the river Danube and for the habitat types scrutinized in this study.The Florix approach was sensitive in data sets testing active against former floodplains and protected against unprotected areas: For the entire reference region ‘Danube floodplain’, Florix values were higher in the active floodplain and in the protected areas. Only the habitat type ‘water bodies’ showed better scores for habitats in the former floodplain, for ‘softwood forests’ the status of being part of a protected area had no effect. Florix results were validated in two case studies differing in land use intensity. The region with dominant agricultural use showed significantly lower values than that with a higher portion of forests and grasslands.Florix can be used for a floristic conservation status assessment at single habitat level or for the entity of a study region in comparison to a reference region. It allows to identify main pressures and to complement a habitat-type based evaluation. To achieve higher comparability, we should strive for a generalized monitoring in Europe like it is common in aquatic ecosystem monitoring.

A meta-analysis of environmental responses to freshwater ecosystem restoration in China (1987–2018)

Understanding how abiotic and biotic components respond to aquatic ecosystem restoration is pivotal for sustainable development in the face of economic development and global environmental change. However, the post-restoration monitoring and evaluation of aquatic ecosystems across large spatial and temporal scales is underfunded or not well documented, especially outside of Europe and North America. We present a meta-analysis of abiotic and biotic indices to quantify post-restoration (2 months–13 years) effects from reported aquatic restoration projects throughout the China-mainland, incorporating 39 lentic and 36 lotic ecosystems. Decreases in dissolved nutrients (total nitrogen, ammonia nitrogen and total phosphorus) post-restoration were rapid, but tended to slow down after about 9.3 years. Response ratios summarizing biodiversity responses (incorporating phytoplankton, invertebrates, vascular plants, fish and birds) typically lagged behind abiotic changes, suggesting longer timescales are needed for biotic indices to recover. Time since restoration interacted with lentic project size showing that, even with the same proportional efforts of restoration, larger lentic ecosystems responded much more slowly than smaller ones. Spatial heterogeneity, reflecting the effects of different restoration approaches (e.g., sewage interception, polluted sediment dredging, artificial wetlands, etc.), had a significantly stronger effect on biotic than abiotic indices, particularly in rivers compared to standing waters. This reflects the complexity of fluvial ecosystem dynamics and hints at a limitation in the reinstatement of ecological processes in these systems to overcome issues such as dispersal limitations. Overall, the different timelines and processes by which abiotic and biotic indices recover after restoration should be taken into account when defining restoration targets and monitoring programs. Our study illustrates the value of long-term aquatic ecosystem monitoring, especially in China given the scale and magnitude of ongoing restoration investments in the country.

Active Biomonitoring of Heavy Metal Concentrations in Aquatic Environment Using Mosses and Algae

In this paper, we present an analysis of the pollution of surface water and air by the heavy metals: Mn, Fe, Ni, Cu, Zn, Cd and Pb in the area of the smelter in Ozimek (Opolskie Voivodeship, Poland). The marine algae Palmaria palmata was exposed in the Mała Panew River, and three species of forest mosses: Pleurozium schreberi, Sphagnum fallax and Dicranum polysetum were also applied. Active biomonitoring was also carried out using P. schreberi mosses to assess air pollution, since the area and the river are influenced by the smelter’s activities. Analytes were determined by atomic absorption spectrometry. Student’s T-test and Mann–Whitney U test were used to assess the significance of differences in elemental concentrations between algae and mosses. Forest mosses were found to have comparable sorption properties to algae under laboratory conditions. During exposure in the river, statistical significance was found between these matrices. The results of water biomonitoring studies using forest mosses offer the possibility of their inclusion in aquatic ecosystem monitoring as an alternative to existing classical surface water biomonitors. Perspectively, attention should be paid to comparing the sorption properties of aquatic species with forest mosses in order to optimize the water biomonitoring system using mosses.

The true picture of environmental DNA, a case study in harvested fishponds

The application of environmental DNA (eDNA) metabarcoding has revolutionised large scale biodiversity monitoring of aquatic ecosystems. Validation studies have been performed mainly in laboratories and mesocosm experiments, however large-scale field experiments are necessary to verify the robustness of eDNA based monitoring for more specific applications and different environmental conditions. Here, eDNA samples were collected from three fishponds with high fish density and broad species diversity during summer and autumn. This sampling design included a large number of spatial replicates evenly spaced across the pond surface and samples from the inflow, while pooled samples were used to test the effect of filtration volumes on detectability. Most common species were detected using eDNA, but rare species were often missed out under these high stocking densities. Average read counts and site occupancy positively correlated strongly with species abundance and biomass, with the exception of samples affected by PCR inhibition. Higher diversity detections were observed in autumn compared to summer samplings and in running compared to standing water. Fish communities detected in pooled samples reflect the overall community structure, and the species detectability increases with higher filtration volumes. This work highlights how eDNA based surveys can be optimised based on sampling conditions to achieve the highest overall detection, which has important implications for applying this method to aid management and policy initiatives.

Applications of Sentinel-2 satellite data for spatio-temporal mapping of deep pools for monitoring the riverine connectivity and assessment of ecological dynamics: a case from Godavari, a tropical river in India (2016-2021).

Rivers are dynamic ecosystems with diverse habitats that require ample connectivity to ensure the flow of ecosystem services, thus empowering the sustainable development of an entire basin. Geo-spatial tools offer powerful prospects for monitoring of aquatic ecosystems. The usefulness of Sentinel-2 datasets to assess river connectivity has been explored for an un-gauged seasonal river system. The present study was undertaken in five ecologically unique river reaches viz. Wainganga, Wardha, Pranhita, Godavari-mid and Manair in Godavari Basin in the Indian Deccan Plateau to map water spread dynamics at various time scales, i.e.,fortnightly, monthly, seasonal, annual and demi-decadal during 2016-2021. The maximum value of perennial water spread per square kilometre of total floodplain area (2016-2021), determined using Sentinel-2 imageries, was observed in river Wardha (0.18) followed by Pranhita (0.12) and Wainganga (0.11). The water spread showed a decreasing trend, while the number of patches in the river corridor increased over time from post-monsoon to pre-monsoon season. The copious perennial habitat with relatively larger patches, incessant flow in river Pranhita and obstructed flow, large-sized patches reported in river Wardha during summer months, hold importance in terms of providing refuge to aquatic biota. This study provides evidence for the impact of water projects on spatio-temporal water spread dynamics in Godavari Basin. The demonstrated utility of Sentinel-2 imagery coupled with gauge station measurements for river continuity assessment and deep pool mapping would aid in enhancing our understanding on environmental flow at a spatial scale, which in turn would aid in effective river management to achieve the Sustainable Development Goals. The implications of this study for sustainable environmental management and limitations are also discussed.

Environmental DNA analysis for macro-organisms: species distribution and more.

In an era of severe biodiversity loss, biological monitoring is becoming increasingly essential. The analysis of environmental DNA (eDNA) has emerged as a new approach that could revolutionize the biological monitoring of aquatic ecosystems. Over the past decade, macro-organismal eDNA analysis has undergone significant developments and is rapidly becoming established as the golden standard for non-destructive and non-invasive biological monitoring. In this review, I summarize the development of macro-organismal eDNA analysis to date and the techniques used in this field. I also discuss the future perspective of these analytical methods in combination with sophisticated analytical techniques for DNA research developed in the fields of molecular biology and molecular genetics, including genomics, epigenomics, and single-cell technologies. eDNA analysis, which to date has been used primarily for determining the distribution of organisms, is expected to develop into a tool for elucidating the physiological state and behaviour of organisms. The fusion of microbiology and macrobiology through an amalgamation of these technologies is anticipated to lead to the future development of an integrated biology.

Incorporating a Hyperspectral Direct-Diffuse Pyranometer in an Above-Water Reflectance Algorithm

In situ hyperspectral remote-sensing reflectance (Rrs(λ)) is used to derive water quality products and perform autonomous monitoring of aquatic ecosystems. Conventionally, above-water Rrs(λ) is estimated from three spectroradiometers which measure downwelling planar irradiance (Ed(λ)), sky radiance (Ls(λ)), and total upwelling radiance (Lt(λ)), with a scaling of Ls(λ)/Ed(λ) used to correct for surface-reflected radiance. Here, we incorporate direct and diffuse irradiance, (Edd(λ)) and Eds(λ)), from a hyperspectral pyranometer (HSP) in an Rrs(λ) processing algorithm from a solar-tracking radiometry platform (So-Rad). HSP measurements of sun and sky glint (scaled Edd(λ)/Ed(λ) and Eds(λ)/Ed(λ)) replace model-optimized terms in the 3C (three-glint component) Rrs(λ) algorithm, which estimates Rrs(λ) via spectral optimization of modelled atmospheric and water properties with respect to measured radiometric quantities. We refer to the HSP-enabled method as DD (direct-diffuse) and compare differences in Rrs(λ) and Rrs(λ) variability (assessed over 20 min measurement cycles) between 3C and DD as a function of atmospheric optical state using data from three ports in the Western Channel. The greatest divergence between the algorithms occurs in the blue part of the spectrum where DD has significantly lower Rrs(λ) variability than 3C in clearer sky conditions. We also consider Rrs(λ) processing from a hypothetical two-sensor configuration (using only the Lt(λ) spectroradiometer and the HSP and referred to as DD2) as a potential lower-cost measurement solution, which is shown to have comparable Rrs(λ) and Rrs(λ) variability to DD in clearer sky conditions. Our results support that the HSP sensor can fulfil a dual role in aquatic ecosystem monitoring by improving precision in Rrs(λ) alongside its primary function to characterize aerosols.

MALAPTERURUS ELECTRICUS, (GMELIN 1789), AND ITS PARASITES, AS HEAVY METAL BIOMONITORS IN LEKKI LAGOON, NIGERIA

The concentration of some heavy metals, Lead, Nickel, Zinc and Iron from the waters, sediment and liver of Malapterurus electricus collected from Lekki Lagoon were investigated. The parasites found inside M.electricus were also investigated for these metals. The concentration of Pb, Ni, Zn and Fe in the liver of M . electricus exceeded the WHO (1993) approved limits and were significantly higher (P<0.01) than those found in the water and sediment of the Lagoon (Pb, 0.976 + 0.79mg/kg, Fe, 24.54 + 55.07mg/kg, Zn, 6.83 + 8.20mg/kg and Ni, 34.20 + 6.26mg/kg). The concentration of Ni (0.089 + 0.050mg/kg), Zn (0.80 + 0.036mg/kg) and Fe (0.950 + 0.030mg/kg) were higher in the sediment than the water samples (Ni, 0.039 + 0.004mg/kg, Zn, 0.175 + 0.019mg/kg and Fe, 0.150 + 0.028mg/kg). The bioaccumulation factors showed that the trend of metal accumulation from the water and sediment and the liver of M. electricus was Fe > Pb > Zn > Ni. Concentrations of Pb, Fe and Zn were higher in females than male, although not significant. M. electricus with condition factors lower than 1.4 (< 1.4) accumulated more of Pb, Zn and Ni while those with condition factor greater than 1.4 (> 1.4) accumulated only Fe. The parasito fauna of M. electricus includes Electrotaenia malopteruri, ( Cestoda) and Procamallanus longus (Nematoda). Both E. malopteruri and P. longus accumulated more heavy metals than the liver of M. electricus. E. malopteruri accumulated 8.6 times more Pb, 3 times more Fe, 43 times more Zn and 4 times more Ni while P. longus accumulated 8.5 times more Pb, 4 times more Fe, 27 times more Zn and 5 times more Nickel than the liver of M . electricus. Bioaccumulation of heavy metals in tissues of fin fish poses a significant threat to the health of end users. Continuous bio monitoring of aquatic ecosystems and enforcement of regulatory laws is therefore essential

Management and Sustainable Exploitation of Marine Environments through Smart Monitoring and Automation

Monitoring of aquatic ecosystems has been historically accomplished by intensive campaigns of direct measurements (by probes and other boat instruments) and indirect extensive methods such as aero-photogrammetry and satellite detection. These measurements characterized the research in the last century, with significant but limited improvements within those technological boundaries. The newest advances in the field of smart devices and increased networking capabilities provided by emerging tools, such as the Internet of Things (IoT), offer increasing opportunities to provide accurate and precise measurements over larger areas. These perspectives also correspond to an increasing need to promptly respond to frequent catastrophic impacts produced by drilling stations and intense transportation activities of dangerous materials over ocean routes. The shape of coastal ecosystems continuously varies due to increasing anthropic activities and climatic changes, aside from touristic activities, industrial impacts, and conservation practices. Smart buoy networks (SBNs), autonomous underwater vehicles (AUVs), and multi-sensor microsystems (MSMs) such as smart cable water (SCW) are able to learn specific patterns of ecological conditions, along with electronic “noses”, permitting them to set innovative low-cost monitoring stations reacting in real time to the signals of marine environments by autonomously adapting their monitoring programs and eventually sending alarm messages to prompt human intervention. These opportunities, according to multimodal scenarios, are dramatically changing both the coastal monitoring operations and the investigations over large oceanic areas by yielding huge amounts of information and partially computing them in order to provide intelligent responses. However, the major effects of these tools on the management of marine environments are still to be realized, and they are likely to become evident in the next decade. In this review, we examined from an ecological perspective the most striking innovations applied by various research groups around the world and analyzed their advantages and limits to depict scenarios of monitoring activities made possible for the next decade.

Paleolimnological assessment of past hydro-ecological variation at a shallow hardwater lake in the Athabasca Oil Sands Region before potential onset of industrial development

Study regionMcClelland Lake, Athabasca Oil Sands Region Study focusEffective environmental monitoring requires knowledge of inherent natural variation. In the absence of pre-development monitoring of aquatic ecosystems, paleolimnological approaches have been championed as a scientifically rigorous method to define pre-development conditions. Motivated by regulatory processes and absence of pre-development data, we conducted a comprehensive paleolimnological study at McClelland Lake to determine an appropriate timeframe for defining natural ranges of variation (NRVs) in hydroecological variables before potential onset of mining within its catchment. New hydrological insights for the regionDuring the past ∼325 years, five distinctive intervals of hydroecological conditions were identified. The first phase (ca. 1695–1750) coincided with the Little Ice Age (LIA), when arid conditions supported lake levels 2.6–3.5 m below present. Phase II (ca. 1750–1840) encompassed subsequent warming, lake-level rise to 1.2–2.6 m below present and increased aquatic productivity. Phase III included frequent natural disturbance by wildfires (ca. 1840–1900). During Phase IV (ca. 1900–1970), the lake deepened and algal communities diversified. Phase V (post–1970) captured influence of regional industrial development, climate warming and lake-level decline, and wildfires. We propose quantitative definitions of NRVs for McClelland Lake be derived from paleolimnological indicators since 1750, which provide a conservative and relevant range of hydroecological conditions, and explore merits and drawbacks of shorter-duration NRV definition for monitoring change.

Isotopic evidence of increasing water abundance and lake hydrological change in Old Crow Flats, Yukon, Canada

Lake-rich northern permafrost landscapes are sensitive to changing climate conditions, but ability to track real-time and potentially multiple hydrological responses (e.g. lake expansion, drawdown, drainage) is challenging due to absence of long-term, sustainable monitoring programs in these remote locations. Old Crow Flats (OCF), Yukon, is a Ramsar Wetland of International Importance where concerns about low water levels and their consequences for wildlife habitat and traditional ways of life prompted multidisciplinary studies during the International Polar Year (2007–2008) and led to the establishment of an aquatic ecosystem monitoring program. Here, we report water isotope data from 14 representative thermokarst lakes in OCF, the foundation of the monitoring program, and time-series of derived metrics including the isotope composition of input waters and evaporation-to-inflow ratios for a 13 year period (2007–2019). Although the lakes spanned multiple hydrological categories (i.e. rainfall-, snowmelt- and evaporation-dominated) based on initial surveys, well-defined trends from application of generalized additive models and meteorological records reveal that lakes have become increasingly influenced by rainfall, and potentially waters from thawing permafrost. These sources of input have led to more positive lake water balances. Given the documented role of rainfall in causing thermokarst lake drainage events in OCF and elsewhere, we anticipate increased vulnerability of lateral water export from OCF. This study demonstrates the value of long-term isotope-based monitoring programs for identifying hydrological consequences of climate change in lake-rich permafrost landscapes.