Large Water Bodies Research Articles

Summer habitat for the female Tricolored Bat (Perimyotis subflavus) in Tennessee, United States

Abstract The Tricolored Bat is an imperiled species due to white-nose syndrome. There is limited information available on roosting and foraging area use of the species to support planning and management efforts to benefit recovery in the Southeastern United States. Female tricolored bats exit hibernation and allocate energy toward disease recovery, migration, and reproduction. Providing and managing for summer habitat is 1 strategy to promote recovery. We sought to: (1) determine local- and landscape-scale factors that influence female Tricolored Bat roost selection; (2) quantify land cover use in core and overall foraging areas; and (3) define foraging area size and distances traveled by female tricolored bats in Tennessee. Bats in this study roosted in trees of variable sizes, in multiple tree species with large canopy volumes, and almost always roosted in trees with dead leaf foliage suspended in the canopy. Forest plots used by bats had trees averaging 30 cm diameter at breast height, basal areas averaging 27 m2/ha, contained multiple tree species, and comprised around a 50:50 ratio of canopy and subcanopy trees. Bats did not roost in coniferous forest areas and were only located in deciduous and mixed forest areas. Bats foraged near and directly over water, in open areas, and along forest edges. This study increases our knowledge on habitat requirements of the species in a temperate region dominated by unfragmented forests and many large water bodies and serves a baseline for management and efforts to benefit survival, reproduction, and population recovery.

A new algorithm for mapping large inland water bodies using CYGNSS

ABSTRACT The persistence of inland water bodies affects climate, biodiversity, and human societies. Among the multiple remote sensing methods, Global Navigation Satellite System Reflectometry (GNSS-R) technology has shown great potential for inland water bodies mapping at very high temporal resolutions. For large inland water bodies with dimensions larger than 350 km, long fetches would roughen water surfaces, thereby causing low-power GNSS returns, posing challenges for mapping them using GNSS-R data, particularly in the case of ultra-large lakes with complicated shorelines, such as Lake Victoria. In this study, we propose an algorithm for mapping Lake Victoria at a 0.01° × 0.01° spatial resolution using GNSS-R data from the Cyclone Global Navigation Satellite System (CYGNSS). By mainly leveraging the surface reflectivity signal, our algorithm extracts lake boundaries and fills the interior to map Lake Victoria. The probability of detection (POD) of the resultant water mask was approximately 90%. This simple and robust algorithm could enhance the capability of monitoring global fast-changing inland water bodies using GNSS-R data, especially in the pan-tropical areas.

Comparing Remote and Proximal Sensing of Agrometeorological Parameters across Different Agricultural Regions in Croatia: A Case Study Using ERA5-Land, Agri4Cast, and In Situ Stations during the Period 2019–2021

The paper evaluates the usability of remote satellite-based and proximal ground-based agrometeorological data sources for precision agriculture and crop production in Croatia. The compared agrometeorological datasets stem from the open-access data sources Copernicus CDS and the Agri4Cast portal, and commercial in situ agrometeorological stations (PinovaMeteo) which monitor environmental parameters relevant to the physiological state of crops. The study compares relevant parameters for 10 different locations in Croatia for three consecutive years (2019, 2020, and 2021) to investigate whether model-based data from ERA5-Land and Agri4Cast are well-correlated with ground measurements from independent in situ stations (PinovaMeteo) for specific agrometeorological parameters (air and soil temperature, and precipitation). Our results indicate the following: both the ERA5-Land and Agri4Cast datasets show mostly strong positive correlations with ground observations for air temperature, modest correlations for soil temperature, but modest or even low correlations for precipitation. Analysis of the residuals indicates higher overall residual values, especially in areas with complex topography and near large bodies of water or the sea, and deviations of residuals that may limit the usability of satellite- and model-based data for decision-making in agriculture.

Assessment of the danger of the release of deep hydrogen sulfide from the Black Sea to the surface

The relevance of this study is due to the fact that the Black Sea is the largest body of water with a hydrogen sulfide zone. The proven reserves of hydrogen sulfide in the water column of the Black Sea amount to five billion tons. In terms of volume, this corresponds to 3.5 trillion cubic meters. At the same time, a mixture of hydrogen sulfide with air is explosive starting with a concentration of hydrogen sulfide in the air of 50 g/ m3. In addition, hydrogen sulfide is toxic, since it is a nerve gas, deadly already at 1 g/ m3. It is of interest to assess the possibility of the release of hydrogen sulfide waters of the sea to the surface with their subsequent degassing, as well as the consequences of increasing the concentration of hydrogen sulfide in surface waters and in the air for coastal areas. The distribution of hydrogen sulfide in the Black Sea is well studied. Especially a lot of measurement data was obtained for the top layer at a depth of 1000 m. Data on the concentration of hydrogen sulfide at depths from 1000 m to 2000 m is significantly less for technical reasons. The maximum concentration of hydrogen sulfide in the sea is reached at depths above 1500 m. A numerical assessment of the consequences of the release of deep waters to the surface has been obtained. It is shown that the concentration of hydrogen sulfide in the air will not exceed 1 g/m3, which is almost two orders of magnitude less than the explosive concentration. The balance estimates of oxygen and hydrogen sulfide fluxes in the Black Sea are considered in connection with forecasts of a rise in the boundary of the hydrogen sulfide zone. It is shown that the rise of the boundary is a consequence of the imbalance of these flows, however, the amount of net hydrogen sulfide production cannot be estimated accurately enough. With an accuracy of estimates of the fluxes themselves of 20-30%, the resulting increase in the amount of hydrogen sulfide per year is a statistically insignificant amount. The release of hydrogen sulfide to the surface in the foreseeable future is possible if the stratification of waters is disrupted by mechanical intervention.

The paleoclimate of the Gediz Graben (Western Türkiye) and archaeological settlement patterns during the Holocene

The Gediz Graben is one of the highly sensitive areas in the Anatolian Peninsula to climatic changes as the climatic patterns in the region have been controlled by both polar and tropical circulation systems. We used readily available results from the CHELSA paleoclimate model and ran the MCM to obtain the paleo-precipitation and paleo-temperature patterns for the research area. This research aims to reconstruct the past climatic conditions of the Gediz Graben during the last 12 ka years through the paleoclimate model results and existing multiple proxy records in the eastern Mediterranean, to contextualize the long-term changes in archaeological settlement patterns in the region. Although we compare the model results here, we base our interpretations of paleoclimate reconstructions on the results of the MCM and the proxy records. The paleoclimatic conditions of the Graben were wetter and colder during the Early Holocene. The Middle and Late Holocene climate was generally stable and near-modern patterns prevailed around 7 ka in the Graben. However, the climatic shifts occurred at smaller amplitudes for shorter periods in comparison to the Early Holocene. These patterns are supported by local and regional proxy records in the eastern Mediterranean. The archaeological settlements in the Plain increased from the Neolithic to the Bronze Age; gathered around large bodies of water. The results suggest that the paleoenvironmental processes (the paleo-lakes, paleoclimatic conditions) contributed to decisions concerning the locales of archaeological settlements on the Gediz Plain.

The Importance of Local Thermal Circulations in PM2.5 Formation in a River Valley: A Case Study From the Lower Yangtze River, China

AbstractPoor air quality is often experienced in densely populated areas located alongside large rivers. The presence of a river valley can modify local meteorology, potentially interfering with the formation of air pollutants such as PM2.5. However, the mechanisms behind PM2.5 formation in river valleys and its impacts on surrounding regions remain poorly understood. This study investigates the formation mechanisms of PM2.5 in the Nanjing reach of the Yangtze River, considering its complex terrain and anthropogenic emissions, through numerical simulation. Simulated results revealed higher PM2.5 concentrations along the Yangtze River compared to the average concentrations in Nanjing, primarily driven by elevated nitrate level. Factors such as higher humidity, wind speed, ageostrophic wind field, and shallow boundary layer were identified as key contributors to the increased PM2.5 concentrations along the river. Our study demonstrates significant impact of local thermal circulations on PM2.5 formation, resulting from the interaction between the large water body of the Yangtze River and the urban area. This phenomenon was confirmed through sensitivity experiments, which showed attenuated local thermal circulations in the absence of the Yangtze River. Source apportionment and process analysis results confirm the dominant roles of local thermal circulation related horizontal and vertical advections, with diurnal fluctuations, in shaping PM2.5 variations along the river. Inorganic chemistry processes also played a non‐negligible role, particularly during polluted conditions. Local thermal circulations in river valleys are crucial for PM2.5 formation, highlighting the need for comprehensive strategies to tackle air pollution in similar regions.

Status of duck breeding in India

Duck is the second most important species of poultry after chicken in India. Due to its many advantages, it is popular in the coastal states and states having large water bodies. Different indigenous and exotic breeds that are being evaluated and reported through research findings are summarized in this review. The history of import of exotic breeds to the country with breeding programme initiated for these breeds in India are discussed with reference to the status of breeds in respect to meat and egg production improved through selection in other countries. The status of purebred selection and breeding programme in indigenous duck being undertaken in our country are very few and being documented with reference to world scenario. Crossbreeding experiment using indigenous and exotic breeds in the countries are reported in respect to growth, conformation traits, production, reproduction, carcass quality, egg quality, egg weight and feed conversion ratio. Performance of the crossbred improved in respect to different traits measured compared to the indigenous breed showing heterosis in positive direction. General combining ability, specific combining ability and reciprocal effects are found to be significant for most of the traits studied in a 3×3 diallel cross using indigenous duck of Odisha, Khaki Campbell and White Pekin. The importance of availability of quality germplasm and performance improvement through duck breeding in India is to be taken on priority. Besides this, the conservation and documentation of all the indigenous breeds and variety is need of the hour. Commercial exploitation of indigenous duck breeds as they are well adapted to our harsh climatic conditions needs to be explored.

Анализ тепловой производительности радиационной системы жизнеобеспечения на основе экспериментальных данных

Solar energy is considered a renewable, most environmentally friendly and carbon-free form of energy. Solar collectors are one of the implementations of radiation life support systems. Their development requires a fairly large amount of initial data, such as the parameters of the premises, the required temperature, volume, thermal insulation of walls, floors and ceilings, the design of windows and doors, orientation to the cardinal points, the angles of inclination of the roof slopes, etc. The next group of factors is related to the location object, latitude, altitude above sea level, distance to large bodies of water, wind rose, etc. The third group is related to the weather itself: precipitation, cloudiness, outside air temperature, etc., a significant part of them, such as fog, haze, dew, shadow from each cloud affects the amount of insolation and all this cannot be taken into account in advance. The use of weather archives does not allow us to fully determine the specific thermal performance of solar collectors, since neither the average nor the current insolation is reflected in the archives. Without knowing the amount of real insolation and heat losses on the solar collector, it is impossible to determine the thermal performance of the radiation life support system per day, month, season or year. This paper discusses experimental and computational studies of the radiation life support system carried out in 2018–2022.

Оценка стадии перемещения наносов при действии волнового потока на элементы русла водного объекта АПК

The purpose of the work is to determine, in laboratory conditions, the magnitude and laws of distribution of bottom wave flow velocities, at which various stages of particle movement and riffle formation occur in the area of beach slopes of water bodies of the agro-industrial complex. The results of studies of velocities characterizing the regimes of sediment movement in a wave flow acting on loose slopes and bottom areas of the shallow zone of reservoirs and streams are presented. The influence of artificial flow turbulization on characteristic flow speeds, including wave speed on the parameters of bottom riffles, is considered. An analysis of the influence of artificial turbulization on the speed of sediment movement is given and recommendations are given for determining the non-erosive speed of the wave flow in its absence. A dependence is presented for determining the height of the riffles. It has been established that the velocities on the riffle crest increase by no more than 1.7 times compared to the speed on the flat bottom of the near-shore zone of a large water body.

Історія вивчення зимової орнітофауни міст України

Knowledge of wintering avifauna and the study of wintering aspects of birds make it possible to obtain information about the diversity and status of the populations of birds during one of the most unfavorable periods of their life. Significant changes in climatic conditions in winter period during the last decades in Europe are noticeable. They affect winter distribution and dynamics of a number of bird species. In particular, new species appear, what may be caused by changes in wintering places or migration routes, or birds that were previously migratory remain for the wintering. Therefore, systematic research of winter avifauna in the territory of urban agglomerations of different levels is a relevant and important task for today. In our opinion, the study of winter avifauna of urban agglomerations can be classified into several groups: year-round, global, partial and selective. The vast majority of winter avifauna studies were partial, conducted by scientists specializing in the study of individual species or groups of birds. Most often, ornithologists focused their attention on predators and birds of the wetland complex. Nowadays, according to the results of research conducted by ornithologists of Ukraine, we can distinguish three distinctive stages, which are not entirely clear, but reflect the development of research on winter avifauna and are indicative in the selection of research objects and territories. The first stage is the study of wintering birds of Ukraine of large water bodies or territories, such as areas with non-freezing ponds; the second – records and study of individual species or groups of birds, in particular wintering of shrikes, representatives of the Corvidae family, and the third – direct research of avifauna in urbocoenoses. The latter stage of research is the most recent. Now, ornithologists drew their attention to avifauna changes in urban agglomerations due to the increasing urbanization rates, which may cause a decrease in the species diversity and number of birds in cities in the nearest future, as a result of their displacement and the impossibility of staying in an anthropogenic environment.

Decolonial Processes in Modern Ukrainian Literature through the Disclosure of the Soviet Man Image. City Space as One of the Identity-Forming Factors

A post-colonial approach to literary studies of modern literature, in particular Ukrainian, has gained considerable popularity over the last decade. Clearly, the collapse of the Soviet Union and the subsequent attainment of independence have laid the foundation for the development of post-colonial studies in our territory. Injuries inflicted during the long period of colonisation (although not all researchers agree to use this term, noting the absence of a key characteristic of the colony — “a large body of water” is missing) have been understood and reflected both in literature and its researchers. However, currently we are at a stage, when writers are moving beyond the refl ection typical for post-colonial viewpoints, delving into the exploration of logical connections between events and their consequences, examining ways to process these traumas. Therefore, in modern research, the decolonial approach, which emerges as a branch of postcolonial thought, is more relevant. In particular, this is discussed by Agnieszka Matusiak and Tamara Hundorova.Tamara Hundorova identifies a unique form of decolonial aesthetics in Ukrainian literature — aesthesis. This is the manifestation of the unknown, even the opposite of the generally accepted modern concept of “aesthetics” — corporeality, sensuality, and mystical practices. Agnieszka Matusiak observes that modern Ukrainian science and culture have undergone a ‘decolonial turn’ (decolonial-detotalitarian, as she calls this phenomenon, a complete shift in emphasis in discussions about Donbas). Decolonisation is intrinsically linked in Ukrainian realities with de-Sovietization. While at the governmental level, this occurs through changing street names and re-evaluating Soviet political figures, people raised under this system find it challenging to shed an identity formed under vastly different values and conditions. The article aims to showcase the depiction and transformation of the Soviet man in modern Ukrainian literature, illustrating changes that signify a shift towards a decolonial perspective. Also of interest are the aspects of traumatic memory and the identity crisis of characters, invariably linked with the disintegration of the Soviet Union.

Identification of urban waterlogging indicators and risk assessment based on MaxEnt Model: A case study of Tianjin Downtown

Waterlogging is one of the world's most dangerous climatic hazards, seriously limiting the safety and sustainable development of cities. Analysis of the factors influencing urban waterlogging and disaster risk assessment are of great importance for the prevention and control of waterlogging. The study constructs a framework for assessing Urban Waterlogging Risk (UWR) from four dimensions: natural condition, social capital, infrastructure and built environment, emphasizing the need to understand and address the vulnerabilities and risks faced by cities in terms of waterlogging. On this basis, the MaxEnt model is used to rank the contribution rate of the indicators and identify positive and negative correlations, as well as to assess the risk of waterlogging and identify waterlogging-prone areas, taking Tianjin Downtown as the research object. The results show that: (1) MaxEnt model has strong applicability for waterlogging risk assessment. (2) The elements with the highest impact on urban waterlogging are population density, impervious surface, precipitation, etc., and prove that the regional waterlogging risk increases with the increase of population, building density, and impervious surface. (3) The high-risk area of waterlogging in Tianjin Downtown is concentrated in the central part of the city, which is characterized by a high degree of development and construction and a dense population; the low-risk area is mainly the area with a low degree of construction at the edge of the city, as well as the area with a large green area or water bodies. In this study, a comprehensive framework for assessing UWR was developed, key factors affecting the spatial distribution of UWR were identified, and the MaxEnt model was used to perform the risk assessment with a high degree of accuracy. The study results can provide a theoretical reference for the urban disaster warning and land use optimization.

The Regulating Effect of Urban Large Planar Water Bodies on Residential Heat Islands: A Case Study of Meijiang Lake in Tianjin

Efficiently harnessing the urban cool island effect associated with large urban aquatic bodies holds significant importance in mitigating the urban heat island (UHI) effect and enhancing the quality of residential living. This study focuses on Tianjin’s Meijiang Lake and its surrounding 47 residential areas, combining Landsat 8 remote sensing satellite data with geographic information system (GIS) buffer analyses and multiple linear regression analyses to reveal the summer thermal characteristics of residential waterfront areas with diverse spatial layouts. The results indicate that: (1) Meijiang Lake’s effective cooling radius extends up to 130 m from the water’s edge, achieving a maximum temperature reduction of 14.44%. Beyond 810 m, the cooling effect diminishes significantly. (2) Waterfront distance (WD), building density (BD), building width (L) and normalized difference vegetation index (NDVI) emerge as the primary factors influencing changes in average land surface temperature (ΔLST) in residential areas. The degrees of influence are ordered as follows: BD > WD > NDVI > L. “Dispersed” pattern residential areas exhibit the most favorable thermal environments, which are primarily influenced by WD, while “parallel” pattern residential areas demonstrate the least favorable conditions, primarily due to WD and NDVI. (3) The direct adjacency of residential areas to large-scale aquatic bodies proves to be the most effective approach for temperature reduction, resulting in a 5.03% lower average temperature compared to non-adjacent areas. Consequently, this study derives strategies for improving the thermal environment via the regulation of spatial planning elements in residential areas, including waterfront patterns, vegetation coverage, WD, and BD.

Comunidades de aves acuáticas de la laguna Mar Chiquita (Córdoba, Argentina)

Mar Chiquita is a large inland brackish water body of about 2,000 km2, with a salinity of around 100 °/oo. Its aquatic bird communities were studied throughout a year in three study areas, representative of the main habitat types found in the región. We collected information on species composition and abundance, as well as foraging behaviour, feeding site utilization and stomach contents.
 In total we recorded 55 species. The richest community (both in number o f species and individuals) was found around the Rio Segundo estuary, while the less diverse corresponde to saline ponds near the coast. Summer migrant species (long range neartic migrants) included nine species and accounted for the 21% of the observed birds. Winter visitors included five species and made up 1% of bird numbers. Ecological guilds species composition and patterns of resource utilization are analyzed. They closely resemble those of marine estuarine and intertidal conditions. At present, the main adverse factors for the preservation of the local aviiauna are linked with planned stream regime modifications through dam building, and contamination due to industrialdevelopment along tributary rivers.

Identifying and Overcoming the Challenges of Offshore Wind Park Noise in Japan

This paper outlines general and specific noise related challenges from the growing demand for offshore wind park developments in the Japanese market. Offshore wind parks can contain a greater number of wind turbines with higher noise emission compared to onshore wind turbines. Japan's bathymetry characteristics impose the necessity to place fixed bottom offshore turbines close to the shore, potentially adding to the overall noise impact on built up coastal areas from onshore wind turbines, railways, roads and other industry. For this reason, careful planning and noise immission prediction for offshore developments is required. The guidelines, from the Office of Odor, Noise and Vibration Ministry of the Environment Government of Japan (2016), for the assessment of wind turbine noise recommend the use of ISO 9613-2:1996 for onshore wind turbines. However, this method is not suited for the propagation over large bodies of water and for offshore wind noise propagation estimation. Therefore, a better understanding of noise propagation over water, such as in the study by Søndergaard et al. (FORCE Technology, 2023), is required, with findings to enhance sustainable development of offshore wind parks.

Natural habitats for the stable existence of wild boars (<em>Sus scrofa</em>) in the North

Wild boar Sus scrofa populations are actively expanding northwards. Their presence in the North is closely tied to anthropogenic activities, as wild boars are either fed, or find food and suitable habitat at farmlands. However, the nature reserves of the northern part of Russia show that wild boars are able to survive on their own even in a completely natural environment. In the taiga zone, there are habitats providing for their survival in winter: wetlands in mires and around large water bodies, and dense spruce forests. Continued northwards expansion of wild boar range is likely if pressure from hunting is reduced. Modelling based on climatic variables also shows that they could potentially inhabit vast areas in the North. The existence of wild boars in the North is interrelated with other species of relatively large mammals (beavers and roe deer) and partly supports the idea of “Pleistocene rewilding” in a boreal environment, i.e., the potential to increase the variety and numbers of megafauna representatives.

Impacts of Urban Morphology on Seasonal Land Surface Temperatures: Comparing Grid- and Block-Based Approaches

Climate change is expected to result in increased occurrences of extreme weather events such as heat waves and cold spells. Urban planning responses are crucial for improving the capacity of cities and communities to deal with significant temperature variations across seasons. This study aims to investigate the relationship between urban temperature fluctuations and urban morphology throughout the four seasons. Through quadrant and statistical analyses, built-environment factors are identified that moderate or exacerbate seasonal land surface temperatures (LSTs). The focus is on Seoul, South Korea, as a case study, and seasonal LST values are calculated at both the grid (100 m × 100 m) and street block levels, incorporating factors such as vegetation density, land use patterns, albedo, two- and three-dimensional building forms, and gravity indices for large forests and water bodies. The quadrant analysis reveals a spatial segregation between areas demonstrating high LST adaptability (cooler summers and warmer winters) and those displaying LST vulnerability (hotter summers and colder winters), with significant differences in vegetation and building forms. Spatial regression analyses demonstrate that higher vegetation density and proximity to water bodies play key roles in moderating LSTs, leading to cooler summers and warmer winters. Building characteristics have a constant impact on LSTs across all seasons: horizontal expansion increases the LST, while vertical expansion reduces the LST. These findings are consistent for both grid- and block-level analyses. This study emphasizes the flexible role of the natural environment in moderating temperatures.

Characterizing biofilms and their associated biosignatures in an Arctic hypersaline cold spring Mars analog

The last surface-level aqueous environments on Mars were likely sulfurous brines that formed as the climate cooled and large bodies of water receded during the transition from the wet Noachian to the dry Hesperian (4.1 – 3.0 Gya). To understand the diversity of microorganisms that could have inhabited such environments and their associated biosignatures, we turn to analogous environments on Earth. Here we investigated biofilm communities and their associated biosignatures at Gypsum Hill, (GH), a perennial cold spring system located at nearly 80°N on Axel Heiberg Island in the Canadian high Arctic. The biofilms develop during the summer months alongside the oligotrophic and sulphur rich GH brines and spread out along the flood plains formed by meltwater and spring run-off. Our objective was to link the microbial community structure of the biofilms to geochemical changes across the GH site as an analog to the micro-niches that could have formed during the recession of an ancient Martian Ocean. We collected 14 morphologically distinct biofilms over two field season and found that minor variations in chemistry between proximal sites impacted community structure. 16S amplicon sequencing revealed that biofilms closest to outflow channels were dominated by sulfur oxidizing bacteria, suggesting that primary production may be driven by chemolithoautotrophy. The community structure shifted towards more heterotrophic and phototrophic populations the further the biofilms appeared from a spring source. Microbial eukaryotes at the GH site were investigated for the first time through 18S sequencing with diatoms and photoautotrophic algae dominating all biofilms. Lastly, we linked the biofilm communities to potential biosignatures by examining lipid profiles to help guide the search and identification of potential remnants of hypothetical ancient Martian life.

Unveiling the origin, fate, and remedial approaches for surfactants in sewage-fed foaming urban (Bellandur) Lake

Foam formation in surface water bodies has become a global phenomenon, but the solutions to this crisis are often insufficient. Foam formation in water bodies is attributed to surfactants and requires a comprehensive assessment of various sources of surfactants to evolve mitigation strategies. The study is focused on thoroughly analyzing surfactants in the water and foam fractions of a large waterbody in Bangalore (India) spanning around 1000 acres (400 ha), which has been foaming for two decades. Results revealed that the key surfactants originate predominantly from anthropogenic sources with a small component emerging from naturogenic sources. Anthropogenic surfactants were found to be predominant (96.5%), with linear alkylbenzene sulphonates (LAS) of various C-chain lengths 12–20 being the most prevalent. Naturogenic surfactants derived from bacterial genera Pseudomonas exhibited significant microbial diversity, accounting for over 19% of total bacterial population in both the water and organic sediments of the lake. Modelling studies and field validation efforts were carried out to understand the fate of LAS in the foaming lake. The results indicated that these surfactants donot degrade under the prevailing conditions and timeframe as wastewater traverses through the lake, and their presence was also observed in the organic sludge sediment. Modeling the underlying processes revealed that a minimum dissolved oxygen (DO) concentration of 3.5 mg/l enables the degradation of over 90% of surfactants within the residence time of 8–10 days in Lake. Additionally, the process of desludging could contribute to an additional increase to the overall efficiency of surfactant removal, simultaneously removing legacy sorbed surfactants to sediments.

Realizing the European Vertical Reference System using model-based hydrodynamic leveling data

All realizations of the European Vertical Reference System (EVRS) computed so far are solely based on geopotential differences obtained by spirit leveling/gravimetry. As such, there are no direct connections between height benchmarks separated by large water bodies. In this study, such connections are added by means of model-based hydrodynamic leveling resulting in a new, yet unofficial realization of the EVRS. The model-derived mean water levels used in computing the hydrodynamic leveling connections were obtained from the Nemo-Nordic (Baltic Sea) and 3D DCSM-FM (northwest European continental shelf) hydrodynamic models. The impact of model-based hydrodynamic leveling on the European Vertical Reference Frame is significant, especially for France and Great Britain. Compared to a solution which only uses spirit leveling/gravimetry, the differences in these countries reach tens to hundreds of hbox {kgal}, hbox {mm}. We also observed an improved agreement with normal heights obtained by differencing GNSS and the European gravimetric quasi-geoid 2015 (EGG2015) heights. In Great Britain, the south-north slope of 48 mm hbox {deg}^{-1} present in the solution which uses only spirit leveling/gravimetry data reduced to 2.2 mm hbox {deg}^{-1}. In France, the improvement is confined to the southwest. The choice of the period over which water levels are averaged has an impact on the results as it determines, among others, the set of tide gauges available to establish the hydrodynamic leveling connections. When using an averaging period that can be considered as the least preferred choice based on three established criteria, the positive impact for France has gone. For Great Britain, the estimated south-north slope became 12.6 mm hbox {deg}^{-1}. This is larger than the slope obtained using the most preferred averaging period but still substantially lower compared to the slope associated with a solution that uses only spirit leveling/gravimetry.