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Gravity currents contribute to the transport of heat and mass in atmospheric and aquatic environments. In aquatic systems subject to daily surface cooling, gravity currents propagate through turbulent convective surroundings. Yet, the effects of thermal convection on aquatic gravity currents remain to be quantified. This paper demonstrates how the interaction between penetrative convection and downslope gravity currents impacts the fluid dynamics and transport across littoral aquatic systems. We performed field experiments in a wind‐sheltered lake experiencing differential cooling to resolve the dynamics of thermally driven gravity currents in convective environments. Our in situ observations reveal that convective plumes penetrate gravity currents, generating large vertical fluctuations that foster the erosion of the stratified layer. This enhanced vertical mixing destroys the stratified downslope flow and limits the basin‐scale transport. Our results demonstrate that the interaction between penetrative convection and downslope gravity currents controls the littoral‐pelagic connectivity in aquatic ecosystems. Plain Language Summary: Horizontal differences in fluid density generate flows called gravity currents. These currents transport heat and mass across environmental systems. The dynamics of gravity current and the resulting transport are well understood when the surroundings are quiescent, which is rarely the case in nature. In aquatic systems, turbulent processes such as convection energize the ambient water. Cooling‐driven convection occurs when the surface of aquatic systems loses heat to the atmosphere, which generates sinking thermal plumes. In this paper, we used a lake experiencing differential cooling as an ideal field‐scale laboratory to investigate the effects of convection on the dynamics of gravity currents. Our in situ observations reveal that convective plumes distort the upper interface of gravity currents and limit the flow intensity. These results demonstrate that convection constrains the horizontal transport induced by gravity currents in natural systems. Key Points: Convective plumes penetrate downslope gravity currents and generate vertical interface fluctuationsVertical convective mixing erodes the stratified downslope flow and limits lateral transportThe time of maximal lateral transport is delayed to the relaxation phase once penetrative convection weakens [ABSTRACT FROM AUTHOR]

Many seasonally stratified lakes accumulate substantial amounts of the greenhouse gas methane in the anoxic zone. Methane oxidizing bacteria in the water column act as a converter, oxidizing methane into carbon dioxide and biomass before it reaches the atmosphere. Current observations and estimates of this methane oxidation efficiency are diverging, especially for the lake overturn period. Here, we combine a model of turbulent mixing, gas exchange, and microbial growth with a comprehensive data set for autumn mixing to quantify the relevant physical and microbial processes for a 16 m deep, wind‐sheltered Swiss lake. Scenario analysis suggests that the methane converter is efficient and robust under a large range of mixing velocities and only rare events of pronounced surface cooling can trigger substantial outgassing. This case study combines in situ observation and a deterministic physically based model and suggests that the frequency of storms may strongly impact methane emissions for similar temperate lakes. [ABSTRACT FROM AUTHOR]

Abstract: We examine nearshore and pelagic current variability in Lake Geneva, a large and deep lake in western Europe, using observations from several measurement locations and a three‐dimensional numerical model for the period 2014–2016. Linear internal seiche modes excited by wind forcing clearly appear as peaks in the energy spectra for measurements in offshore locations. In contrast, spectra from the nearshore data, where currents interact with the lake bed, reveal a negligible contribution of internal seiches to the total kinetic energy. A similar contrast is seen in the spectra obtained from the numerical model at the same locations. Comparing the contribution of the different terms in the vertically averaged momentum equation from the modeling results shows that the nonlinear advective term dominates in the nearshore boundary layer. Its contribution decays with distance from shore. The width of this nearshore boundary layer, which may extend for several kilometers, seems to be mainly determined by local topography. Both field measurements and modeling results indicate that nonlinear dynamics are of primary importance in the nearshore boundary layer. [ABSTRACT FROM AUTHOR]

The in vitro inhibitory action and metabolism of 1-beta-D-arabinofuranosylcytosine (ara-C) on human myeloid (HL-60), B-lymphoid (RPMI-8392), and T-lymphoid (Molt-3) leukemic cells was compared. Ara-C produced greater inhibitory effects in Molt-3 cells than in either HL-60 or RPMI-8392 cells. At a 48 h exposure, ara-C was 7 and 10 times more cytotoxic to Molt-3 cells than to HL-60 and RPMI-8392 cells, respectively. The total ara-C uptake to nucleotides and the formation of 1-beta-D-arabinofuranosylcytosine 5'-triphosphate (ara-CTP) was about 5 times greater in Molt-3 cells than in either HL-60 or RPMI-8392 cells. The incorporation of ara-C into DNA was also higher in Molt-3 cells than in either HL-60 or RPMI-8392 cells. The mean intracellular half-life of ara-CTP was 31.7, 59.4, and 155 min for RPMI-8392, HL-60, and Molt-3 leukemic cells, respectively. The Km and Vmax values of ara-C for deoxycytidine kinase and the feedback inhibition of this enzyme by ara-CTP in the different leukemic cell lines could not explain the differences in metabolism of this analogue in these cells. These data indicate the increased sensitivity of T-lymphoid leukemic cells to ara-C than as compared with B-lymphoid and myeloid leukemic cells was due to an increased rate of formation and a longer half-life of ara-CTP in the T-cells. [ABSTRACT FROM AUTHOR]

Methane (CH 4 ) accumulation in the well-oxygenated lake epilimnion enhances the diffusive atmospheric CH 4 emission. Both lateral transport and in situ oxic methane production (OMP) have been suggested as potential sources. While the latter has been recently supported by increasing evidence, quantifying the exact contribution of OMP to atmospheric emissions remains challenging. Based on a large high-resolution field data set collected during 2019-2020 in the deep stratified Lake Stechlin and on three-dimensional hydrodynamic modeling, we improved existing CH 4 budgets by resolving each component of the mass balance model at a seasonal scale and therefore better constrained the residual OMP. All terms in our model showed a large temporal variability at scales from intraday to seasonal, and the modeled OMP was most sensitive to the surface CH 4 flux estimates. Future efforts are needed to reduce the uncertainties in estimating OMP rates using the mass balance approach by increasing the frequency of atmospheric CH 4 flux measurements.

Lakes emit substantial amounts of carbon dioxide (CO 2 ) into the atmosphere, but why they do remains debated. The long-standing vision of lakes as solely respirators of the organic matter leaking from the soils has been challenged by evidence that inorganic carbon produced by weathering of the catchment bedrock could also support lake CO 2 emissions. How inorganic carbon inputs ultimately generate lake CO 2 outgassing remains a blind spot. We develop and introduce a calcite module in a coupled one-dimensional physical-biogeochemical model that we use to simulate the carbon cycle of the large Lake Geneva over the past 40 years. We mechanistically demonstrate how the so-far neglected process of calcite precipitation boosts net CO 2 emissions at the annual scale. Far from being anecdotal, we show that calcite precipitation could explain CO 2 outgassing across various lakes globally, including some of the largest lakes in the world.

Three-dimensional lake hydrodynamic model is a powerful tool widely used to assess hydrological condition changes of lake. However, its computational cost becomes problematic when forecasting the state of large lakes or using high-resolution simulation in small-to-medium size lakes. One possible solution is to employ a data-driven emulator, such as a deep learning (DL) based emulator, to replace the original model for fast computing. However, existing DL-based emulators are often black-box and data-dependent models, causing poor interpretability and generalizability in practical applications. In this study, a data-driven emulator is established using deep neural network (DNN) to replace the original model for fast computing of three-dimensional lake hydrodynamics. Then, the Koopman operator and transfer learning (TL) are employed to enhance the interpretability and generalizability of the emulator. Finally, the generalizability of DL-based emulators is comprehensively analyzed through linear regression and correlation analysis. These methods are tested against an existing hydrodynamic model of Lake Zurich (Switzerland) whose data was provided by an open-source web-based platform called Meteolakes/Alplakes. According to the results, (1) The DLEDMD offers better interpretability than DNN because its Koopman operator reveals the linear structure behind the hydrodynamics; (2) The generalization of the DL-based emulators in three-dimensional lake hydrodynamics are influenced by the similarity between the training and testing data; (3) TL effectively improves the generalizability of the DL-based emulators., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Zhenliang Liao reports financial support was provided by National Natural Science Foundation of China. Zhenliang Liao reports financial support was provided by Key Laboratory of Surveying and Mapping Science and Geospatial Information Technology of Ministry of Natural Resources., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The extent of littoral influence on lake gas dynamics remains debated in the aquatic science community due to the lack of direct quantification of lateral gas transport. The prevalent assumption of diffusive horizontal transport in gas budgets fails to explain anomalies observed in pelagic gas concentrations. Here, we demonstrate through high-frequency measurements in a eutrophic lake that daily convective horizontal circulation generates littoral-pelagic advective gas fluxes one order of magnitude larger than typical horizontal fluxes used in gas budgets. These lateral fluxes are sufficient to redistribute gases at the basin-scale and generate concentration anomalies reported in other lakes. Our observations also contrast the hypothesis of pure, nocturnal littoral-to-pelagic exchange by showing that convective circulation transports gases such as oxygen and methane toward both the pelagic and littoral zones during the daytime. This study challenges the traditional pelagic-centered models of aquatic systems by showing that convective circulation represents a fundamental lateral transport mechanism to be integrated into gas budgets.

Freshwater algae exhibit complex dynamics, particularly in meso-oligotrophic lakes with sudden and dramatic increases in algal biomass following long periods of low background concentration. While the fundamental prerequisites for algal blooms, namely light and nutrient availability, are well-known, their specific causation involves an intricate chain of conditions. Here we examine a recent massive Uroglena bloom in Lake Geneva (Switzerland/France). We show that a certain sequence of meteorological conditions triggered this specific algal bloom event: heavy rainfall promoting excessive organic matter and nutrients loading, followed by wind-induced coastal upwelling, and a prolonged period of warm, calm weather. The combination of satellite remote sensing, in-situ measurements, ad-hoc biogeochemical analyses, and three-dimensional modeling proved invaluable in unraveling the complex dynamics of algal blooms highlighting the substantial role of littoral-pelagic connectivities in large low-nutrient lakes. These findings underscore the advantages of state-of-the-art multidisciplinary approaches for an improved understanding of dynamic systems as a whole., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2024.)

Introduction: Bioconvection, a phenomenon characterized by the collective upward swimming of motile microorganisms, has mainly been investigated within controlled laboratory settings, leaving a knowledge gap regarding its ecological implications in natural aquatic environments. This study aims to address this question by investigating the influence of bioconvection on the eco-physiology of the anoxygenic phototrophic sulfur bacteria community of meromictic Lake Cadagno., Methods: Here we comprehensively explore its effects by comparing the physicochemical profiles of the water column and the physiological traits of the main populations of the bacterial layer (BL). The search for eco-physiological effects of bioconvection involved a comparative analysis between two time points during the warm season, one featuring bioconvection (July) and the other without it (September)., Results: A prominent distinction in the physicochemical profiles of the water column centers on light availability, which is significantly higher in July. This minimum threshold of light intensity is essential for sustaining the physiological CO 2 fixation activity of Chromatium okenii , the microorganism responsible for bioconvection. Furthermore, the turbulence generated by bioconvection redistributes sulfides to the upper region of the BL and displaces other microorganisms from their optimal ecological niches., Conclusion: The findings underscore the influence of bioconvection on the physiology of C. okenii and demonstrate its functional role in improving its metabolic advantage over coexisting phototrophic sulfur bacteria. However, additional research is necessary to confirm these results and to unravel the multiscale processes activated by C. okenii's motility mechanisms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Di Nezio, Roman, Buetti-Dinh, Sepúlveda Steiner, Bouffard, Sengupta and Storelli.)

Chromium stable isotope composition (δ 53 Cr) is a promising tracer for redox conditions throughout Earth's history; however, the geochemical controls of δ 53 Cr have not been assessed in modern redox-stratified basins. We present new chromium (Cr) concentration and δ 53 Cr data in dissolved, sinking particulate, and sediment samples from the redox-stratified Lake Cadagno (Switzerland), a modern Proterozoic ocean analog. These data demonstrate isotope fractionation during incomplete (non-quantitative) reduction and removal of Cr above the chemocline, driving isotopically light Cr accumulation in euxinic deep waters. Sediment authigenic Cr is isotopically distinct from overlying waters but comparable to average continental crust. New and published data from other redox-stratified basins show analogous patterns. This challenges assumptions from δ 53 Cr paleoredox applications that quantitative Cr reduction and removal limits isotope fractionation. Instead, fractionation from non-quantitative Cr removal leads to sedimentary records offset from overlying waters and not reflecting high δ 53 Cr from oxidative continental weathering., (© 2022. The Authors.)

Severe deterioration of water quality in lakes, characterized by overabundance of algae and declining dissolved oxygen in the deep lake (DO B ), was one of the ecological crises of the 20th century. Even with large reductions in phosphorus loading, termed "reoligotrophication," DO B and chlorophyll (CHL) have often not returned to their expected pre-20th-century levels. Concurrently, management of lake health has been confounded by possible consequences of climate change, particularly since the effects of climate are not neatly separable from the effects of eutrophication. Here, using Lake Geneva as an iconic example, we demonstrate a complementary alternative to parametric models for understanding and managing lake systems. This involves establishing an empirically-driven baseline that uses supervised machine learning to capture the changing interdependencies among biogeochemical variables and then combining the empirical model with a more conventional equation-based model of lake physics to predict DO B over decadal time-scales. The hybrid model not only leads to substantially better forecasts, but also to a more actionable description of the emergent rates and processes (biogeochemical, ecological, etc.) that drive water quality. Notably, the hybrid model suggests that the impact of a moderate 3°C air temperature increase on water quality would be on the same order as the eutrophication of the previous century. The study provides a template and a practical path forward to cope with shifts in ecology to manage environmental systems for non-analogue futures.

In recent decades, lakes have experienced unprecedented ice loss with widespread ramifications for winter ecological processes. The rapid loss of ice, resurgence of winter biology, and proliferation of remote sensing technologies, presents a unique opportunity to integrate disciplines to further understand the broad spatial and temporal patterns in ice loss and its consequences. Here, we summarize ice phenology records for 78 lakes in 12 countries across North America, Europe, and Asia to permit the inclusion and harmonization of in situ ice phenology observations in future interdisciplinary studies. These ice records represent some of the longest climate observations directly collected by people. We highlight the importance of applying the same definition of ice-on and ice-off within a lake across the time-series, regardless of how the ice is observed, to broaden our understanding of ice loss across vast spatial and temporal scales., (© 2022. The Author(s).)

Anomaly detection is the process of identifying unexpected data samples in datasets. Automated anomaly detection is either performed using supervised machine learning models, which require a labelled dataset for their calibration, or unsupervised models, which do not require labels. While academic research has produced a vast array of tools and machine learning models for automated anomaly detection, the research community focused on environmental systems still lacks a comparative analysis that is simultaneously comprehensive, objective, and systematic. This knowledge gap is addressed for the first time in this study, where 15 different supervised and unsupervised anomaly detection models are evaluated on 5 different environmental datasets from engineered and natural aquatic systems. To this end, anomaly detection performance, labelling efforts, as well as the impact of model and algorithm tuning are taken into account. As a result, our analysis reveals the relative strengths and weaknesses of the different approaches in an objective manner without bias for any particular paradigm in machine learning. Most importantly, our results show that expert-based data annotation is extremely valuable for anomaly detection based on machine learning., (Copyright © 2021. Published by Elsevier Ltd.)

Water inherent optical properties (IOPs) contain integrative information on the optical constituents of surface waters. In lakes, IOP measurements have not been traditionally collected. This study describes how high-frequency IOP profiles can be used to document short-term physical and biogeochemical processes that ultimately influence the long-term trajectory of lake ecosystems. Between October 2018 and May 2020, we collected 1373 high-resolution hyperspectral IOP profiles in the uppermost 50 m of the large mesotrophic Lake Geneva (Switzerland-France), using an autonomous profiler. A data set of this size and content does not exist for any other lake. Results showed seasonal variations in the IOPs, following the expected dynamic of phytoplankton. We found systematic diel patterns in the IOPs. Phases of these diel cycles were consistent year-round, and amplitudes correlated to the diurnal variations of dissolved oxygen, clarifying the link between IOPs and phytoplankton metabolism. Diel amplitudes were largest in spring and summer under low wind condition. Wind-driven changes in thermal stratification impacted the dynamic of the IOPs, illustrating the potential of high-frequency profiles of water optical properties to increase our understanding of carbon cycling in lake ecosystems.

Water quality measures for inland and coastal waters are available as discrete samples from professional and volunteer water quality monitoring programs and higher-frequency, near-continuous data from automated in situ sensors. Water quality parameters also are estimated from model outputs and remote sensing. The integration of these data, via data assimilation, can result in a more holistic characterization of these highly dynamic ecosystems, and consequently improve water resource management. It is becoming common to see combinations of these data applied to answer relevant scientific questions. Yet, methods for scaling water quality data across regions and beyond, to provide actionable knowledge for stakeholders, have emerged only recently, particularly with the availability of satellite data now providing global coverage at high spatial resolution. In this paper, data sources and existing data integration frameworks are reviewed to give an overview of the present status and identify the gaps in existing frameworks. We propose an integration framework to provide information to user communities through the the Group on Earth Observations (GEO) AquaWatch Initiative. This aims to develop and build the global capacity and utility of water quality data, products, and information to support equitable and inclusive access for water resource management, policy and decision making., Competing Interests: Conflicts of Interest: The authors declare no conflict of interest.

A 66-year-old woman presented to the hospital with cutaneous necrosis of her right ankle and foot. Her symptoms began immediately after an intra-articular injection of hyaluronic acid for ankle osteoarthritis, which was performed 6 days before. Histopathology showed an intra-vascular hyaluronic acid embolus. The initial treatment approach was conservative, but the patient's clinical state degraded. She was thus treated with sub-cutaneous hyaluronidase, the enzyme that degrades hyaluronic acid, which yielded a moderate improvement even though it was administered 22 days after the initial hyaluronic acid injection. Although hyaluronic acid embolism and subsequent cutaneous necrosis are well-known complications of dermal fillers, there are few reported cases of embolism following intra-articular injection. To our knowledge, this is the first time hyaluronidase has been used in this setting., Competing Interests: Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article., (© The Author(s) 2021.)

Water-level fluctuation (WLF) is a widespread management action in lakes and reservoirs whose impacts on contaminant fate have seldom been investigated. We used near shore hourly measurements (n = 2122) of turbidity (contaminant proxy) and water velocity (sediment resuspension proxy) to track high-frequency contaminant dynamics during a 0.6 m change in water level observed in autumn 2017 in a large French lake. Simultaneously, discrete trace metal measurements highlighted that trapped sediment was more contaminated and finer than surficial sediment supporting that suspended particles (measured by turbidity) were a preferential medium for contaminant mobility. General additive models involving tensor products revealed the enhancement of wind-speed and river discharge effects on turbidity with water draw down. The decrease of the explained deviances by the models over time-lags indicated short time-scale response of turbidity to external forcing. Three of the four major turbid events occurred at the lowest water-level and were concomitant of sediment resuspension as well as precipitation events and/or river flood suggesting a complex interplay among in-lake and watershed processes at controlling sediment mobility during the WLF. These results shed in light that WLF can affect lake littoral hydrodynamic cascading up to the enhancement of contaminant mobility. Sediment resuspension may be an overlooked feature of WLF increasing contamination risk and exposure for littoral organisms with widespread ecological consequences due to the large number of water-level regulated ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Environmental management depends on high-quality monitoring and its meaningful interpretation. The combination of local weather dynamics, regional anthropogenic stresses and global environmental changes make the evaluation of monitoring information in dynamic freshwater systems a challenging task. While the lake ecosystems gather many complex biogeochemical interactions, they remain constrained by the same physical environment of mixing and transport. It is therefore crucial to obtain high-quality physical system insight. Three-dimensional hydrodynamic models are perfectly suited for providing such information. However, these models are complex to implement, and their use is often limited to modellers. Here, we aim to provide model output via a user-friendly platform to a broad audience ranging from scientists to public and governmental stakeholders. We present a unified approach merging the apparently diverse interests through meteolakes.ch, an online platform openly disseminating lake observations and three-dimensional numerical simulations in near real-time with short-term forecasts and data assimilation. Meteolakes is scalable to a broad range of devices, modular and distributed, hence allowing its expansion to other regions and hardware infrastructures. Since 2016, the platform has continuously provided timely synoptic lake information to more than 250,000 users. This web-based system was built not only to provide guidance to scientists in the design and analysis of field experiments and to foster interdisciplinary lake studies, but also to assist governmental agencies and professionals in the long-term policy and planning of water resources management. Finally, our system aimed at promoting awareness and understanding of the complexity of lakes and providing information to the public through user-friendly interfaces. This article details the design and operation of such a platform and its products. Applications are demonstrated by examples of a recent upwelling and a storm event. Both cases illustrate how Meteolakes help scientists in their quest for process understanding as well as water professionals and civil society in providing specific warnings., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Competing Interests: Competing interests: None declared.

Extreme weather events may be just as important as gradual trends for the long-term trajectories of ecosystems. For alpine lakes, which are exposed to both exacerbated atmospheric warming and intense episodic weather events, future conditions might not be appropriately forecast by only climate change trends, i.e. warming, if extreme events have the potential to deflect their thermal and metabolic states from their seasonal ranges. We used high-frequency monitoring data over three open-water seasons with a one-dimensional hydrodynamic model of the high-altitude Lake Muzelle (France) to show that rainstorms or windstorms, notwithstanding their intensity, did not trigger long-lasting consequences to the lake characteristics when light penetration into the lake was not modified. In contrast, storms associated with high turbidity input from the watershed ("turbid storms") strongly modified the lacustrine hydrodynamics and metabolism for the rest of the open-water season through reduced light penetration. The long-lasting effects of turbid storms were related to the inputs and in-lake persistence of very light glacial suspensoids from the watershed. The occurrence of the observed turbid storms was not related to the wind or rain intensities during the events. Instead, the turbid storms occurred after dry and atypically warm spells, i.e. meteorological conditions expected to be more frequent in this alpine region in the upcoming decades. Consequently, storm events, notwithstanding their intensity, are expected to strongly imprint the future ecological status of alpine lakes under climate warming., (© 2018 John Wiley & Sons Ltd.)

Human impacts on biodiversity are well recognized, but uncertainties remain regarding patterns of diversity change at different spatial and temporal scales. Changes in microbial assemblages are, in particular, not well understood, partly due to the lack of community composition data over relevant scales of space and time. Here, we investigate biodiversity patterns in cyanobacterial assemblages over one century of eutrophication and climate change by sequencing DNA preserved in the sediments of ten European peri-Alpine lakes. We found species losses and gains at the lake scale, while species richness increased at the regional scale over approximately the past 100 years. Our data show a clear signal for beta diversity loss, with the composition and phylogenetic structure of assemblages becoming more similar across sites in the most recent decades, as have the general environmental conditions in and around the lakes. We attribute patterns of change in community composition to raised temperatures affecting the strength of the thermal stratification and, as a consequence, nutrient fluctuations, which favoured cyanobacterial taxa able to regulate buoyancy. Our results reinforce previous reports of human-induced homogenization of natural communities and reveal how potentially toxic and bloom-forming cyanobacteria have widened their geographic distribution in the European temperate region.

Understanding the dynamics and fate of particle bound contaminants is important for mitigating potential environmental, economic and health impacts linked to their presence. Vidy Bay, Lake Geneva (Switzerland), is contaminated due to the outfall and overflow from the wastewater treatment plant of the City of Lausanne. This study was designed to investigate the fate of particle-bound contaminants with the goal of providing a more complete picture of contaminant pathways within the bay and their potential spread to the main basin. This goal was achieved by investigating the sediment transport dynamics, using sediment traps and radionuclide tracers, and ascertaining how local bottom-boundary hydrodynamic conditions (temperature, turbidity, current velocity and direction) influence these dynamics. Results of the study indicated that sedimentation rates and lateral advections increased vertically with proximity to the lakebed and laterally with proximity to shore, indicating the presence of sediment focusing in the bay. Hydrodynamic measurements showed the persistent influence of a gyre within the bay, extending down to the lake bed, while just outside of the bay circulation was influenced by the seasonal patterns of the main basin. Calculated mean displacement distances in the bay indicated that suspended particles can travel ∼3 km per month, which is 1.7 times the width of the Vidy Bay gyre. This results in a residence time of approximately 21 days for suspended particles, which is much greater than previously modelled results. The calculated mobility Shield parameter never exceeded the threshold shear stress needed for resuspension in deeper parts of the bay. In such, increased lateral advections to the bay are not likely due to local resuspension but rather external particle sources, such as main basin or shallow, littoral resuspensions. These external sources coupled with an increased residence time and decreased current velocity within the bay are the precipitating factors in sediment focusing. While the spread of contaminants from the bay may occur through the transport of fine suspended sediments in shallower zones of the bay (<60 m) by longshore littoral currents, results suggest that particle-bound contaminants are likely to remain within the bay.

Directives and legislations worldwide aim at representatively and continuously monitoring the ecological status of surface waters. In many countries, chlorophyll-a concentrations (CHL) are used as an indicator of phytoplankton abundance and the trophic level of lakes or reservoirs. In-situ measurements of water quality parameters, however, are time-consuming, costly and of unknown but naturally limited spatial representativeness. In addition, the variety of the involved lab and field measurement methods and instruments complicates comparability and reproducibility. Taking Lake Geneva as an example, 1234 satellite images from the MERIS sensor on the Envisat satellite from 2002 to 2012 are used to quantify the spatial and temporal variations of CHL concentrations. Based on histograms of spring, summer and autumn CHL estimates, the spatial representativeness of two existing in-situ measurement locations is analysed. Appropriate sampling frequencies to capture CHL peaks are examined by means of statistical resampling. The approaches proposed allow determining optimal in-situ sampling locations and frequencies. Their generic nature allows for adaptation to other lakes, especially to establish new survey programmes where no previous records are available., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Deep dermatophytosis of genital skin is a rare clinical manifestation of infection by a common group of pathogens., Objective: We emphasize the importance of clinical suspicion and the use of accurate diagnostic methods in the evaluation of deep dermatophytosis., Methods: We report a single case of tinea pubis, kerion type, caused by Trichophyton mentagrophytes in an immunocompetent host., Results: A 54-year-old female presented with a suppurative infection of the vulva and pubis that was unresponsive to empirical antibiotic therapy. T. mentagrophytes was isolated. Oral itraconazole was initiated on the basis of clinical suspicion and continued for a total of 6 weeks., Conclusion: Accurate diagnosis and treatment of deep dermatophytosis of genital skin rests upon proper identification of the pathogen. Prompt initiation of treatment with an oral antifungal agent, such as itraconazole, should be undertaken in order to avoid irreversible scarring alopecia.