Open Water Bodies Research Articles

Analysis of the environmental status and measures for safety and environmental protection in oil and gas producing areas

Environmental pollution in the areas of drilling and field development is one of the main priority environmental problems. At the same time, as observations show, the main objects of pollution are groundwater, hydro-and lithosphere (open water bodies, the bottom of water areas, soil and vegetation cover). Sources of pollution are the results of the process itself. The greatest danger posed to environmental objects is technological drilling waste, which is accumulated and stored directly on the drilling site. Drilling waste includes drilling cuttings, waste drilling fluids and drilling wastewater. They are formed in the process of washing the well. In the process of deepening a well at the bottomhole, a drill is formed. Hydrotransport that drills mud from the bottom of the well to the surface of the rock under the influence of man-made factors turns into drill cuttings. Therefore, in the cleaning system of the circulating system of a drilling rig, the cuttings are not separated from the drilling fluid. But drill cuttings differ in volume and, most important from an environmental point of view, in physicochemical properties. The volume of cuttings is equal to the volume of the wellbore. When designing, the volume of drill cuttings is approximately taken by 20% more than the volume of cuttings.

Assessment of the Safe Isolation of Solid Radwaste in Subsurface Repositories

A calculation of the removal of radionuclides by groundwaters from a subsurface repository of solid low-level waste was performed. A two-dimensional model of the groundwater flow and advective-dispersive transport of radionuclides in a vertical section of a subsurface aquifer, along which radionuclide-contaminated groundwater moves from the repository to an open body of water, was studied. Data from many years of experimentation on the leaching of cemented low-level waste were used in the calculations. It was shown that the rocks of the aquifer effectively retain medium half-life radionuclides (60Co, 137Cs, 90Sr). An engineered barrier – a 0.7 m thick layer of consolidated bentonite clay – can secure the safety of a repository for long-lived transuranium radionuclides (235U, 239Pu) for 20000 years.

Habitat selection by American beaver at multiple spatial scales

BackgroundSemiaquatic mammals require both aquatic and terrestrial habitats, particularly interfaces between the two habitats. As ecosystem engineers, American beaver (Castor canadensis) consume and fell a great amount of deciduous trees. We tested the prediction that open water and amounts of food resources, including hardwood forests (i.e., deciduous trees as the dominant form of vegetation), herbaceous and woody wetlands, and shrubs, would influence the second-order habitat selection (i.e., placing home ranges on the landscape) by American beaver, whereas the third-order habitat selection of American beaver would be associated with woody wetland and shrub edges. We investigated hierarchical habitat selection by American beaver using location data from very high frequency telemetry. Dirichlet-multinomial models were used to determine the second-order habitat selection at landscape scales. Bayesian spatial resource selection function was used to assess the third-order habitat selection within home ranges.ResultsSecond-order habitat selection by American beaver was associated with herbaceous wetland, shrubs, hardwood forest, grassland, and woody wetland more than open water bodies at landscape scales. At the third-order scale, American beaver selected herbaceous wetlands as well as the edges of shrubs and woody wetland within established home ranges.ConclusionsSpatial distributions of food resources affected both the second- and third-order habitat selection by American beaver. Herbaceous wetlands were more important habitat components than water bodies in the second- and third-order habitat selection by American beaver. Dirichlet-multinomial distribution models for the second-order habitat selection and Bayesian spatial resource selection functions for the third-order habitat selection do not need pseudo-absence locations, providing alternative approaches to the presence–absence methods for habitat selection by animals.

Geospatial analysis of the depletion of surface water body and floodplains in Dhaka City (1967 to 2008) and its implications for earthquake vulnerability

Dhaka city the capital of Bangladesh experienced unprecedented urban growth since the country’s independence in 1971. A significant portion of the urbanization took place in the encroached surface water body and floodplain (SWB and FP) areas. We thus aimed to capture the depletion of SWB and FP in Dhaka city from 1967 to 2008 using geospatial analysis and evaluated its implications for earthquake vulnerability. We used CORONA (1967) and QuickBird (2008) satellite images to compare the pre- and post-urbanization status of SWB and FP. We identified a striking change occurred during this period with a total loss of 33% of SWB and FP areas. The channelized water body faced a depletion of 15%, while the open water body which mainly includes the floodplains experienced a loss of 38%. The urban structures built on the depleted SWB and FP are highly vulnerable to ground motion and liquefaction of earthquake. We found that 90% of the depleted areas have a shear wave velocity in the top 30 m of soil thickness (Vs30) of 180–360 m/s, while the rest has a Vs30 value of 15. We produced an earthquake vulnerability map based on the information of surficial geology, Vs30, LPI and found that substantial areas near the southern, eastern, and western boundaries of the city scored highly in the vulnerability map. The results of the study can support formulation of rational earthquake preparedness strategy for Dhaka.

Assessing Changes in Ecosystem Services Provision in Coastal Waters

Coastal ecosystems are important ecosystem services (ES) suppliers. The degradation of these ecosystems jeopardizes the quality of ES provision. The Biodiversity 2020 Strategy aims at maintaining and restoring ES, although clear guidelines are missing on how to define the state to which ES should be restored. In this respect, synergies between ES assessments and the Water Framework Directive (WFD) exist, but methodological approaches to connect both are lacking. The Marine Ecosystem Services Assessment Tool (MESAT) can overcome this problem. In this study, the tool is applied to semi-open and open coastal water bodies in the Southern Baltic Sea, the Greifswald Bay and Pomeranian Bay. The resulting changes in ES provision confirm the ability of MESAT to be applied in all WFD water body types and a multitude of environmental and anthropogenic gradients. Nevertheless, problems such as data scarcity, spatial extent and historical background of the case studies require adaptations in the assessment process. The spatial extent of all case studies allowed to cover a connected system with a strong environmental (salinity) gradient. Analyzing changes in ES provision in connected systems can help to better understand linkages between ES provision and environmental and anthropogenic stressors as well as trade-offs between ES across water bodies. This information can be further used to support the design of management plans. From the analysis of all MESAT case studies, major factors were identified for the tool to be transfered into a European context, as well as potential problems and solutions. Following the WFD is a strong advantage, which ensures the tool’s transferability to other areas.

THE OBJECTS OF THE NATURAL ENVIRONMENT, AS FACTORS OF TRANSMISSION OF PARASITOSIS

Sanitary parasitological study of the contamination of environmental objects as factors of parasitosis transmission is an important element of sanitary and hygienic monitoring. Using sanitary-parasitological methods of research of environmental objects in 2018, wastewater and its sediments, soil and water of open surface water bodies as the main factors of parasitosis transmission were studied in the territory of the Rostov region and the Republic of Adygea. Screening works were carried out to indicate 137 objects of the surrounding environment that the parasitosis pathogens infected. Extensive and intensive indicators of the contamination of objects with the ascertained viability of the identified parasitic pathogens were determined. Wastewater and its sediments turned out to be the most epidemiologically significant objects, as evidenced by the level of contamination of these substrates with parasitic pathogens and to a greater degree the share of viable helminth eggs detected among them. The spectrum of parasitic pathogens detected in both territories in sewage and sediments was as follows: tokocar eggs (more than 50%), ascaris eggs, pinworms, taeniid oncospheres, ankylostomid eggs, dicrocelium, diphyllobotriid. The soil remains one of the main components of the environment, of great importance in the spread of parasitic invasions. In the studied areas, the ovogram of detected parasitic pathogens in the soil was almost identical: eggs of ascaris, tokocar, pinworms, etc. In addition, the maximum epidemiological significance of the soil was established for geo-and contact helminth infections in respect of the territories of residential areas of settlements, pre-school institutions. The investigated water samples of open surface reservoirs contained only non-viable helminth eggs with low contamination intensity (1–2 specimens / 25 l.).

Quantification of the Evaporation Rates from Six Types of Wetland Cover in Palo Verde National Park, Costa Rica

The hydrology of tropical seasonal wetlands is affected by changes in the land cover. Changes from open water towards a vegetated cover imply an increase in the total evaporation flux, which includes the evaporation from open water bodies and the transpiration from vegetated surfaces. This study quantified the total evaporation flux of six covers of the Palo Verde wetland during dry season. The selected wetland covers were dominated by Neptunia natans (L.f.) Druce, Thalia geniculata L., Typha dominguensis Pers., Eichhornia crassipes (Mart.) Solms, a mixture of these species, and open water conditions. The plants were collected from the wetland and placed in lysimeters (59.1 L) built from plastic containers. The lysimeters were located in an open area near the meteorological station of the Organization for Tropical Studies (OTS). The evaporated water volume and meteorological data were collected between December 2012–January 2013. A completely randomized design was applied to determine the total evaporation (E), reference evaporation ( E ref , Penman-Monteith method) and crop coefficient ( K c ) for all the covers. T. geniculata (E: 17.0 mm d − 1 , K c : 3.43) and open water (E: 8.2 mm d − 1 , K c : 1.65) showed the highest and lowest values respectively, for daily evaporation and crop coefficient. Results from the ANOVA indicate that E. crassipes and N. natans were statistically different (p = 0.05) from T. dominguensis and the species mixture, while the water and T. geniculata showed significant differences with regard to other plant covers. These results indicate that the presence of emergent macrophytes as T. geniculata and T. dominguensis will increase the evaporation flux during dry season more than the floating macrophytes or open water surfaces.

SANITARY-HYGIENIC CHARACTERISTICS OF THE AREA OF POSITIONING FOR THE DISPOSAL OF ROCKET TECHNICS

There was executed the sanitary-hygienic assessment of residential areas in the zone of possible impact of industrial activity of the Center for the elimination of Intercontinental ballistic missiles affiliated to the Federal State Unitary Enterprise “Center for Operation of Ground-Based Space Infrastructure Facilities” located in the Nizhny Novgorod region. There were performed full-scale studies of air samples, water reservoirs and sources of drinking water, the soil on the content of components of liquid rocket fuels and their degradation products. Studies have shown full-time work enterprises not to be accompanied by the emission of unsymmetrical dimethyl hydrazine, Tetramethyl-2-tetrazene, NDMA into the environment. In samples of water from open stagnant water bodies there was detected both dimethylamine in concentrations exceeding MPC by 1.1 - 1.3 times, and formaldehyde in the concentration below the MAC. All soil samples also contain FA and DMA in concentrations significantly lower than the MPC. As, Be, Cd, Pb in drinking water was not detected within the sensitivity of the method, Ni content, Zn, Mg, Mn, Al does not exceed hygienic standards. Fe content in the water of centralized water supply amounted to 1.5 MAC.

Automatic Detection of Open and Vegetated Water Bodies Using Sentinel 1 to Map African Malaria Vector Mosquito Breeding Habitats

Providing timely and accurate maps of surface water is valuable for mapping malaria risk and targeting disease control interventions. Radar satellite remote sensing has the potential to provide this information but current approaches are not suitable for mapping African malarial mosquito aquatic habitats that tend to be highly dynamic, often with emergent vegetation. We present a novel approach for mapping both open and vegetated water bodies using serial Sentinel-1 imagery for Western Zambia. This region is dominated by the seasonally inundated Upper Zambezi floodplain that suffers from a number of public health challenges. The approach uses open source segmentation and machine learning (extra trees classifier), applied to training data that are automatically derived using freely available ancillary data. Refinement is implemented through a consensus approach and Otsu thresholding to eliminate false positives due to dry flat sandy areas. The results indicate a high degree of accuracy (mean overall accuracy 92% st dev 3.6) providing a tractable solution for operationally mapping water bodies in similar large river floodplain unforested environments. For the period studied, 70% of the total water extent mapped was attributed to vegetated water, highlighting the importance of mapping both open and vegetated water bodies for surface water mapping.

Telemetry reveals the habitat selected by immature dragonflies: implications for conservation of the threatened dragonfly Leucorrhinia caudalis (Odonata: Anisoptera)

Determining how species use different habitats during critical phases of their development is one of the crucial challenges that conservation biology meets. However, habitat requirements remain unknown for most species, in particular for the rarest and most threatened which by definition are difficult to study. Here, we used animal-borne telemetry to identify the habitat of the sexually immature adults in the threatened dragonfly Leucorrhinia caudalis. We used an harmonic radar with customized tags fixed on the back of the abdomen of flying immature dragonflies to monitor their position within an area composed of various types of habitats including open areas, forest and water bodies. From 62 tagged individuals, we obtained 23 detections, all within a quite restricted area around the pond of emergence. About 75% of the detections happened in the forest canopy and the individuals were likely positioned at the top of the trees. The relatively low detection rate was probably due to high predation within the study area during the maturation phase in this dragonfly but long-range dispersal cannot be excluded. The use of forest canopy as a maturation habitat is an important knowledge for planning conservation strategies in this endangered species, especially for populations living in areas without any protection status. Although technological constraints are still limiting its efficiency, animal-borne telemetry appears to be useful to determine precisely habitat selection by rare species.

Water-related land cover data products for geospatial analysis and modeling of infectious disease transmission risks

Event Abstract Back to Event Water-related land cover data products for geospatial analysis and modeling of infectious disease transmission risks Xiangming Xiao1*, Geli Zhang2, JInwei Dong3, Zhenhua Zou1, Xinxin Wang4 and Marius Gilbert5 1 University of Oklahoma, United States 2 China Agricultural University (CAU), China 3 Institute of Geographic Sciences and Natural Resources Research (CAS), China 4 Fudan University, China 5 Free University of Brussels, Belgium Transmission of many zoonotic infectious diseases is associated with the spatial-temporal changes in habitats, hosts, and vectors. One example is the highly pathogenic avian influenza viruses (HPAIV), and its transmission is closely related to the spatial distribution and movement of domestic ducks and wild water fowls which use water-related land cover types (e.g., open surface water body, natural wetland, and rice paddy) as their habitats. In the past decades, land use change and climate change have substantially and rapidly altered the spatial distribution and temporal dynamics of water-related land cover types, which calls for accurate and timely updated data, information, and knowledge of those water-related land cover types across the local, regional, national, and global scales. In this presentation, we will provide an update on water-related land cover data products from analyses of satellite images over years, including open surface water body, natural wetland, and rice paddy in China, USA, monsoon Asia, and the globe. We will also introduce the case studies that use these geospatial datasets in risk assessment and modeling of infectious diseases. We hope that this presentation will stimulate more discussion and collaboration between the geospatial science community, which focuses on the use of satellite images to track and monitor land use and land cover changes, and the animal and human health science community, which focuses on the epidemiology and ecology of infectious diseases that affect both animal and human health. Acknowledgements The research was supported by the National Institutes of Health (NIH) NIAID grant (1R01AI101028-01A2). Keywords: Surface water, aquaculture, wetlands, Rice paddies, remote sensing, avian influenza Conference: GeoVet 2019. Novel spatio-temporal approaches in the era of Big Data, Davis, United States, 8 Oct - 10 Oct, 2019. Presentation Type: Regular oral presentation Topic: Spatial data sources, open data, accessibility and information integration Citation: Xiao X, Zhang G, Dong J, Zou Z, Wang X and Gilbert M (2019). Water-related land cover data products for geospatial analysis and modeling of infectious disease transmission risks. Front. Vet. Sci. Conference Abstract: GeoVet 2019. Novel spatio-temporal approaches in the era of Big Data. doi: 10.3389/conf.fvets.2019.05.00052 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 07 Jun 2019; Published Online: 27 Sep 2019. * Correspondence: Prof. Xiangming Xiao, University of Oklahoma, Norman, United States, xiangming.xiao@ou.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Xiangming Xiao Geli Zhang JInwei Dong Zhenhua Zou Xinxin Wang Marius Gilbert Google Xiangming Xiao Geli Zhang JInwei Dong Zhenhua Zou Xinxin Wang Marius Gilbert Google Scholar Xiangming Xiao Geli Zhang JInwei Dong Zhenhua Zou Xinxin Wang Marius Gilbert PubMed Xiangming Xiao Geli Zhang JInwei Dong Zhenhua Zou Xinxin Wang Marius Gilbert Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Assessment and Trend of Land Cover Land Use Changes in Owerri and Environs, South Eastern Nigeria

This study examined land cover and land use changes (LCLUC) in Owerri and environs from 1986 to 2016 and went further to determine the trend in the change of each LCLUC class. The satellite imagery of the area over the three decades was characterized into the different LCLUC classes and the changes in the areal extent of the different LCLUC classes were calculated and plotted, followed with the estimation of the trend using linear regression analysis method. The result revealed that over the three decades, forests and sparse vegetation respectively decreased at a rate of 0.73% and 0.05% of the total land area per year while built up areas increased almost equally in the opposite direction at a rate of 0.65% of the total land area per year. Open spaces and water bodies decreased at the rate of 0.11% and 0.02% of the total land area respectively which were as a result of the pressure for resources like land and sand for built infrastructure. A model was derived for the LCLUC and it revealed that Owerri and environs may be devoid of vegetal cover in about 2 decades (2039) if the current rate of conversion of forests to built-up infrastructure is not abated. This whole LCLUC scenario if not controlled may trigger changes in the local climate of the area and urgent steps are therefore needed to create awareness to all the stakeholders in the area on the need for sustainable land and natural resources use, tree planting, urban spatial plan and controls in order to safeguard the environment, ecosystem and climate of the area for the future.

Structure and regional representativeness of the herpetofauna from Parque Estadual da Serra de Caldas Novas, Cerrado, Central Brazil

ABSTRACTAmphibians and reptiles are diversified in the Cerrado biome but have been threatened by habitat loss and fragmentation, as well as lack of understanding of their distribution. Therefore, collection and organization of information about species in natural environments are essential for conservation, especially in Protected areas (PAs) and their adjacent zones. We present information about the composition and structure of the herpetofauna from Parque Estadual da Serra de Caldas Novas (PESCAN) and its representativeness in comparison to other PAs in the Cerrado. Fieldwork was conducted in 12 sampling sites from February 2009 to February 2010, using active search and pitfall traps. We recorded 41 species of amphibians, with greatest richness in sites with open vegetation and water bodies. Reptiles were represented by 32 species, with the greatest species richness in cerrado open environments. Both amphibian and reptile communities were more similar to those from geographically closer PAs and located in the central region of the Cerrado (State of Goiás and Distrito Federal). The PESCAN holds 24.85% and 17.98% of amphibians and reptiles species occurring in Cerrado PAs, respectivelly. This large representativeness and the high number of endemisms (18 amphibians and 7 reptiles) emphasize the importance of the PESCAN, together with other PAs, for the maintenance of regional biodiversity. In addition, we also encourage researches evaluating amphibian and reptile communities outside PAs, such as legal reserves, and we suggest new approaches to study the biodiversity of protected areas.

Impact of Urbanisation on Land Use/Land Cover in Puducherry City, India

The change of land use plays a major role in the developmental activity of a developing country. Due to rapid growth of urbanisation and dramatic increasing population, the fertile agricultural land has been converted to built-up area with respect to the demand for housing requirement and to the need for basic infrastructure facilities. The quantum of open space and surface water bodies has also been encroached. There has been a rapid growth of population in Puducherry city from 3.48 million in 1991 to 5.44 million in 2011. Hence the conservation of natural resources becomes one of the major challenges especially in small and medium town. This study was conducted to assess the effect of change on land use in urban agglomeration area of Puducherry city for the duration period from 1997 to 2017. There has been an increase in population in Puducherry city mainly attributed to higher scale of migration from adjoining rural areas and medium town for better education, job opportunities and quality life. Hence, it has been strongly recommended for stringent Development Control Regulations to quantify the urban sprawl and manage the impact of urbanisation of land use/land cover in Puducherry city.

Assessment of land use land cover changes in Loktak Lake in Indo-Burma Biodiversity Hotspot using geospatial techniques

Increased in human anthropogenic activities resulted in large degradation of wetlands affecting the biotic and abiotic components of the freshwater ecosystems. The Loktak Lake of Manipur in the Indo-Burma Biodiversity region has been degraded and threatened due to increase in population and the demand for more resources. The aim of the present study was to assess the changes in land use pattern in Loktak Lake during the last 38 years using digital change detection approaches. Spatial technique of land uses detection using multi-temporal satellite data followed by remote sensing techniques were used to assess the land cover changes. Maximum likelihood algorithm was employed to analyze the data collected from the Earth Resource Development Assessment System imagine in order to detect the change in land cover. Further, five types of land use pattern viz. open water bodies, agricultural area, Phumdis with thick vegetation, Phumdis with thin vegetation and settlement were studied. The results showed an alternation in the land use profile of the Loktak Lake. The present finding indicates that overall increased in open water bodies, agricultural area and settlement by 10.94%, 10.26% and 2.23% respectively while Phumdis with thick and Phumdis with thin vegetation have decreased by 3.48% and 28.89%. Changes in land use pattern were found to be affecting the fragile ecosystem of the Loktak Lake and posed a serious threat to the aquatic ecosystem. The study identified the need for proper land use planning and implementation of Manipur Loktak Lake Act 2006 for sustainable management of the lake.

Tracking annual changes of coastal tidal flats in China during 1986–2016 through analyses of Landsat images with Google Earth Engine

Tidal flats (non-vegetated area), along with coastal vegetation area, constitute the coastal wetlands (intertidal zone) between high and low water lines, and play an important role in wildlife, biodiversity and biogeochemical cycles. However, accurate annual maps of coastal tidal flats over the last few decades are unavailable and their spatio-temporal changes in China are unknown. In this study, we analyzed all the available Landsat TM/ETM+/OLI imagery (~44,528 images) using the Google Earth Engine (GEE) cloud computing platform and a robust decision tree algorithm to generate annual frequency maps of open surface water body and vegetation to produce annual maps of coastal tidal flats in eastern China from 1986 to 2016 at 30-m spatial resolution. The resulting map of coastal tidal flats in 2016 was evaluated using very high-resolution images available in Google Earth. The total area of coastal tidal flats in China in 2016 was about 731,170 ha, mostly distributed in the provinces around Yellow River Delta and Pearl River Delta. The interannual dynamics of coastal tidal flats area in China over the last three decades can be divided into three periods: a stable period during 1986–1992, an increasing period during 1993–2001 and a decreasing period during 2002–2016. The resulting annual coastal tidal flats maps could be used to support sustainable coastal zone management policies that preserve coastal ecosystem services and biodiversity in China.

Fatal drowning in the Western Cape, South Africa: a 7-year retrospective, epidemiological study

IntroductionDrowning is a neglected public health threat in low-income and middle-income countries where the greatest drowning burden is observed. There is a paucity of drowning surveillance data from low-resource settings,...

Mapping and classifying green infrastructure typologies for climate-related studies based on remote sensing data

Despite the current evidence on the thermal benefits of vegetation and water bodies, further research is needed to investigate how cooling capacities are influenced by particular types, amounts, and spatial arrangements of green infrastructure (GI). However, there are no commonly agreed typologies that can be confidently used to compare and report the existing climatological effects of GI. Two previous studies were conducted to respond to this gap, and a conceptual GI typology matrix was developed according to functional, structural and configurational attributes. The present research presents a streamlined version and tests its applicability for the automated mapping, classification and thermal evaluation of GI using remote sensing data. A combination of parameters is introduced, including surface cover fractions and FRAGSTATS metrics estimated from very high-resolution hyperspectral imagery, LiDAR and cadastral data. The proposed framework can be applied at different spatial scales to analyse large urban areas rapidly and with high spatial accuracy. This paper also proposes a replicable workflow that can be implemented by researchers and practitioners to map existing vegetation conditions, prioritise greening interventions and assess thermal conditions with greater confidence. In this study, this workflow was successfully applied at local scale to classify green open spaces, tree canopies and water bodies in the city of Sydney. Evidence presented here demonstrates the applicability of the proposed system to evaluate and compare the intra- and inter-typology variability of land surface temperatures (LSTs), which can be potentially applied for performance assessment across other ecosystem service categories. Despite satisfactory results, the proposed typology is contingent on further developments and tests on a larger spatial extent and with a greater number of observations. Further statistical analysis is also required to determine the cooling capacity of typologies and quantify the influence of measured parameters on LSTs.

Metalimnetic oxygen minimum and the presence of Planktothrix rubescens in a low-nutrient drinking water reservoir

Dissolved oxygen is a key player in water quality. Stratified water bodies show distinct vertical patterns of oxygen concentration, which can originate from physical, chemical or biological processes. We observed a pronounced metalimnetic oxygen minimum in the low-nutrient Rappbode Reservoir, Germany. Contrary to the situation in the hypolimnion, measurements of lateral gradients excluded the sediment contact zone from the major sources of oxygen depletion for the metalimnetic oxygen minimum. Instead, the minimum was the result of locally enhanced oxygen consumption in the open water body. A follow-up monitoring included multiple chlorophyll a fluorescence sensors with high temporal and vertical resolution to detect and document the evolution of phytoplankton. While chlorophyll fluorescence sensors with multiple channels detected a mass development of the phycoerythrin-rich cyanobacterium Planktothrix rubescens in the metalimnion, this species was overlooked by the commonly used single-channel chlorophyll sensor. The survey indicated that the waning P. rubescens fluorescence was responsible for the oxygen minimum in the metalimnion. We hypothesize that pelagic processes, i.e., either oxygen use through decomposition of dead organic material originating from P. rubescens or P. rubescens extending its respiration beyond its photosynthetic activity, induced the metalimnetic oxygen minimum. The deeper understanding of the oxygen dynamics is mandatory for optimizing reservoir management.

Inland wetlands mapping and vulnerability assessment using an integrated geographic information system and remote sensing techniques

The understanding of inland wetlands’ distribution and their level of vulnerability is important to enhance management and conservation efforts. The aim of the study was to map inland wetlands and assess their distribution pattern and vulnerability to natural and human disturbances such as climate change (temperature increase) and human activities by the year 2080. Inland wetland types i.e. forested/shrub, emergent and open water bodies were classified and mapped using maximum likelihood standard algorithm. The spatial distribution pattern of inland wetlands was examined using average nearest neighbor analysis. A weighted geospatial vulnerability analysis was developed using variables such as roads, land cover/ land use (developed and agricultural areas) and climate data (temperature) to predict potentially vulnerable inland wetland types. Inland wetlands were successfully classified and mapped with overall accuracy of about 73 percent. Clustered spatial distribution pattern was found among all inland wetland types with varied degree of clustering. The study found about 13 percent of open water bodies, 11 percent of forested/shrub and 7 percent of emergent wetlands potentially most vulnerable to human and natural stressors. This information could be used to improve wetland planning and management by wetland managers and other stakeholders.