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Inland waters are among the most threatened biodiversity hotspots. Ponds located in alpine areas are experiencing more rapid and dramatic water temperature increases than any other biome. Despite their prevalence, alpine ponds and their biodiversity responses to climate change have been poorly explored, reflecting their small size and difficult access. To understand the effects of climate change on alpine pond biodiversity, we performed a comprehensive literature review for papers published since 1955. Through analysis of their geographic distribution, environmental features, and biodiversity values, we identified which environmental factors related to climate change would have direct or indirect effects on alpine pond biodiversity. We then synthesized this information to produce a conceptual model of the effects of climate change on alpine pond biodiversity. Increased water temperature, reduced hydroperiod, and loss of connectivity between alpine ponds were the main drivers of biodiversity geographic distribution, leading to predictable changes in spatial patterns of biodiversity. We identified three major research gaps that, if addressed, can guide conservation and restoration strategies for alpine ponds biodiversity in an uncertain future. [ABSTRACT FROM AUTHOR]

Poor and unreliable knowledge of the status of freshwater fisheries limits their inclusion in governance processes, thereby impeding effective management measures. This threatens the livelihoods of people, particularly in developing countries. Improved knowledge is required to draw the attention of policymakers and stimulate effective management measures to accelerate the sustainability of the freshwater fisheries. In line with this requirement, this paper provides the state of knowledge of the aquatic ecosystem and fisheries of the Lake Edward system, East Africa, focusing on lakes Edward, George and the Kazinga channel. The state of knowledge was accomplished by reviewing existing data and information on aspects of primary productivity and water quality, invertebrates, fish fauna, fish life history and ecology, and fisheries. The waterbodies have been monitored since the 1930s, albeit sporadically, providing data on all the above aspects but with substantial temporal gaps. Adequate and updated data and information exist on the water quality status of the water bodies, extant aquatic taxa (including fishes) and fish catches but with uncertainties in the latter. Data and information gaps exist on the abundance of biotic communities, fish life history, quantitative trophic ecology and fisheries management reference points. The aggregated data and information can directly support decisions for fisheries management. We recommend regular monitoring to fill the data and information gaps, more comprehensive stock assessments and the development of aquatic ecosystem models. [ABSTRACT FROM AUTHOR]

Duck decoys are trapping devices designed to catch ducks. From the fourteenth century onwards, duck decoys emerged in riverine lowlands in northwestern Europe. Their operation is based on a rigorously maintained physical structure with a woodland that encloses a water body with protruding extensions called pipes, which end in nets and are surrounded by reed screens. Catching ducks in these places requires a complex interplay between different groups of ducks, a dog, and a human decoyman who together are enmeshed in what becomes a deeply deceptive landscape. This paper explores duck decoys in the Netherlands as relational, situated and co‐designed multispecies atmospheres. Through ethnographic descriptions of field visits, interviews and by drawing on historical accounts, we trace how inter‐ and intraspecies relations and behaviours are interpreted in terms of deception, betrayal, trust and curiosity. The varying interpretations of behaviours and the more‐than‐human knowledges at play reflect the essentially elusive character of the duck decoy. Especially when facing the environmental challenges of the Anthropocene, duck decoys and the ambiguous relations that were until recently maintained in them, encourage us to consider the historical trapping and hunting landscapes as places made by multispecies atmospheres. Even though these atmospheres and the intimate collectives of human and more‐than‐human lives have become increasingly fragile, their afterlives resonate through the changing character of the riverine landscape and its various waterfowl, as well as practices of knowing and conserving biodiversity. [ABSTRACT FROM AUTHOR]

Humans and water have a complex relationship that includes various dimensions such as sociocultural, political, legal and ecological. Considering the ubiquity of water, we need a more holistic perspective to help us see water not as a static entity but rather as one in constant movement, physically and conceptually; acknowledging the interplay between water and humans is essential to understanding societal narratives deeply embedded in places. In this special section, an interdisciplinary group of scholars explore inland waters, taking a water‐centric view instead of a land‐centric one. The special section delves into the emerging hydro‐social connections, diverse forms of expertise, governance models, collective and spontaneous actions, and resilience strategies within the context of inland water bodies, exploring how canals, rivers and wetlands are experienced and represented as places. The papers in this collection show that any form of placemaking should take responsible stewardship of water, embrace its dynamic nature, and present a realistic pathway towards sustainable solutions for present and future water challenges. [ABSTRACT FROM AUTHOR]

The hydrological patterns of all natural water bodies pulse in variable rhythms of high and low water. The biodiversity of these ecosystems is driven by the changing nature of the environment, allowing different life strategies to coexist, e.g., by the fast reuse of nutrients when aquatic biota flourish in the recently wetted zones and vice versa. Much of the human culture in hydroscapes has developed as an adaptation to this rhythm, e.g., by using the flood‐fertilised floodplains for agriculture or fisheries, or by seasonal migration into or out of the floodplain (transhumance). Technological advances have allowed humans to control, change, or even eliminate this natural water rhythm by building dams, dikes, and canals. Consequently, important ecosystem functions fail, often resulting in failure of human life‐support systems but also in the failure and decline of cultural activities. I argue that the loss of socio‐cultural connectivity to the rhythms of rivers and other hydrosystems occurs in four phases: (i) loss of direct relationships (e.g., uses of waterborne resources), (ii) loss of indirect relationships (cultural activities that are connected to theses uses), (iii) turning away from the river/hydrosystem (often caused by decreased water quality), and (iv) total oblivion (caused by removal or burial of the hydrosystem). Reintegrating more riverine rhythms into human life would not mean to step back in time but rather to find a combination of revised traditional ecological knowledge, learning from nature, changing values in the context of use of natural resources, and innovations. This paper draws on social‐environmental aspects of the River Culture Concept – which attempts to reintegrate respect for the pulsing nature of hydrosystems into modern, sustainable management – and on diverse case studies. Examples are presented on how River Culture Concept approaches may contribute to revitalising socio‐ecological linkages to the rhythm of the waters. [ABSTRACT FROM AUTHOR]

River contracts (RCs) are voluntary agreements between stakeholders for managing water bodies and involve participatory, evidence‐based action plans. Increasingly, European authorities recognise that effective water policies require bottom‐up, inclusive decision‐making. Despite widely held assumptions about the benefits of including stakeholders in river basin management and encouraging participatory mechanisms of decision‐making, the growing rhetoric about the need for public engagement implies that this 'new' paradigm of water management remains filled with ambiguities. Adopting ethnographic methods and drawing on a variety of primary and secondary sources, this paper analyses three RCs in the Friuli Venezia Giulia region of Italy. These case studies reveal the potential for RCs as tools not only for water management, but also for increasing stakeholder involvement through place‐making activities conceived as potential hydrophilic encounters. In order to understand whether RCs contribute to a fluvial sense of place, we looked at the effects of top‐down versus participatory processes. We asked whether RCs were considered participatory processes designed to achieve a co‐designed outcome or simply territorial management projects that objectify the river as something to be developed. We found that ratifying an RC was not, in itself, proof of an effective process; rather the nature and quality of an RC was determined by the degree and type of participation. We contend that participatory events and sharing information are not sufficient in themselves to achieve the active involvement of all stakeholders. We argue that the best framework for enabling place‐making and enhancing a sense of place is to develop RCs within a process that includes a high degree of participation. This enables citizens to shift from simply being passive recipients of plans to becoming effective territorial actors. [ABSTRACT FROM AUTHOR]

One of the biggest threats faced in the present world is environmental degradation and pollution which is caused by an increase in the concentration of toxic substances which leads to the destruction of the ecosystem which gets exposed to those particles, it also leads to the loss of ecosystems because when these toxic particles seep into soil or water bodies, the life forms or the habitat which depend on it gets affected by the effluents hence leading to adverse effects, biomagnification and even death which dismantles the entire ecosystem. In this article, we will be discussing the effects on the environment caused by mining activities which are highly detrimental to the area in which it is done. Mining involves breaking down the soil layer into depths to extract various minerals and geological substances which in turn destroys the environment which gets exposed to it. As machinery is used they destroy the soil layer completely hence resulting in erosion of the area completely rendering it useless for any vegetation to grow. Apart from these by‐products and effluents which are released from the mining sites when seeps into nearby soil and water bodies can be very much detrimental to the respective ecosystem there. Moreover, the loosening of soil destroys its rigidity hence landslides can occur which is deadly. Thus to control all that, preventive measures need to be taken to improvise the mining activity in such a way that dangers of environmental degradation can be minimized as much as possible. Therefore this paper deals with the environmental impacts of mining activities along with remedial measures to control the toxic concentration from the sites (Chaney, 1991). [ABSTRACT FROM AUTHOR]

The Indo‐Burma biodiversity hotspot has one of the world's most species‐rich inland waters. However, its freshwater biodiversity faces habitat loss and species extinction due to large‐scale development of water resources, pollution, exploitation of native biota, and introduced non‐native species.These threats include the South American suckermouth armoured catfishes, Pterygoplichthys spp., that have invaded parts of this biodiversity hotspot. Pterygoplichthys spp. are among the most impactful introduced fishes globally and pose a 'very high risk' of becoming invasive once introduced.This paper aims to compile a distribution database for Pterygoplichthys spp., map their current global distribution, and estimate their potential distribution extent in the Indo‐Burma biodiversity hotspot using MaxEnt.In the Indo‐Burma region, Pterygoplichthys spp. have already been reported from China, Myanmar, Thailand and Vietnam, with populations also present in neighbouring India, Bangladesh, Malaysia, Singapore and Indonesia. No populations were verified for Cambodia and Laos.A maximum entropy model was developed based on the current global distribution of Pterygoplichthys spp. The species distribution model showed that the entire biodiversity hotspot, except the spine of the Arkan Mountains and the Hengduan Mountains from Three Gorges to the Hong River Valley, is suitable for Pterygoplichthys spp. An effective temperature of 15°C was identified as the lower limit of Pterygoplichthys spp. habitat suitability.Pterygoplichthys spp. were identified as a high‐risk taxon for freshwaters of almost the entire Indo‐Burma biodiversity hotspot. A coordinated management plan for Pterygoplichthys spp. is required to safeguard the freshwater biota of the Indo‐Burma freshwater ecosystems. [ABSTRACT FROM AUTHOR]

In this paper, we use remotely sensed imagery to identify the location and size of animal feeding operations in the Maumee River Watershed, a key drainage area to Lake Erie's Western Basin, which has recently experienced severe harmful algal blooms. We then estimate the relationship between the intensity of animal feeding operations in the watershed and surface water body concentrations of dissolved reactive phosphorus (DRP), the pollutant most responsible for algal growth. We find that stream reaches with relatively larger increases in upstream animal feeding exposure experience significantly higher increases in concentrations of DRP. The average marginal upstream animal feeding operation in the watershed increases downstream DRP concentrations by between 10% and 15%. In contrast, when restricting the analysis to include only permitted operations, coefficient estimates are practically zero and statistically insignificant. Our work presents evidence that the increasing intensity of animal feeding operations contributes to water quality problems. Permitting and identification of animal feeding operations is therefore important for managing runoff and correctly attributing the causes of excess nutrients in surface water bodies. [ABSTRACT FROM AUTHOR]

Lakes host a high level of biodiversity, especially in their littoral zone, and provide various ecological and socio‐economic services. Lake ecosystems are impacted by a combination of pressures from different human activities (industry, hydroelectricity, agriculture, recreational activities, domestic and urban uses). Anthropic pressures can lead to alterations and dysfunctions in lakes, particularly in the littoral zone.The 2000 EU Water Framework Directive led to considerable efforts to improve the ecological status of European water bodies. However, in France, measures implemented by lake managers to counteract, limit or suppress anthropogenic impacts are still poorly identified. Moreover, their effects on hydromorphology, physico‐chemistry and biotic communities are often only partially reported (the monitoring being incomplete or heterogeneous, if not missing).This paper proposes a framework to harmonize the monitoring of habitat improvement actions conducted in the littoral zone of lakes. The monitoring method is presented as well as the sampling protocols and techniques set out to survey both the restored and control zones at the European French territory scale.Long‐term monitoring of hydromorphological, biological and physicochemical features is expected to improve our understanding of recolonization mechanisms following restoration. The proposed approach will therefore guide practitioners to identify the best restoration options and ultimately contribute to the conservation of recipient populations and communities. [ABSTRACT FROM AUTHOR]

Here, we present a comprehensive holography‐based system designed for detecting microparticles through microscopic holographic projections of water samples. This system is designed for researchers who may be unfamiliar with holographic technology but are engaged in microparticle research, particularly in the field of water analysis. Additionally, our innovative system can be deployed for environmental monitoring as a component of an autonomous sailboat robot. Our system's primary application is for large‐scale classification of diverse microplastics that are prevalent in water bodies worldwide. This paper provides a step‐by‐step guide for constructing our system and outlines its entire processing pipeline, including hologram acquisition for image reconstruction. [ABSTRACT FROM AUTHOR]

Benthic primary producers (BPP) in inland waters, including aquatic macrophytes and periphyton, are foundational habitats that are highly sensitive to multiple human drivers of environmental change. However, long‐term seasonal monitoring of BPP is limited, leaving us with little information on the cause, directionality, and consequences of the potential shifts in timing of BPP life cycle events. Here, we review the literature on the phenological changes of BPP and show that BPP respond primarily to temperature, but also to other interactive drivers related to climate change and eutrophication. In addition, we present four rare case studies where BPP display strong and earlier shifts in event timing associated with increasing temperature and discuss potential impacts of these changes on ecosystem functioning. Given the responsive nature of BPP to multiple human drivers, we provide suggestions on how to improve basic monitoring to better understand the future impact of phenological changes of this critical habitat. [ABSTRACT FROM AUTHOR]

HiRISE images and digital elevation models (DEMs) of outcrops in candidate Martian glaciovolcanoes provide more detailed evidence for glaciovolcanic processes than has previously been available for Mars. A group of ridges in the Pavonis Mons fan‐shaped glacial deposit features pervasive layering, evidence for local collapse and slumping, and steeper faces in the direction of paleoglacier flow inferred from other features in the deposit. After comparison with terrestrial analogs, we conclude that these ridges are excellent candidates for tephra‐dominated tindar, formed in phreatomagmatic subglacial eruptions. The englacial meltwater lakes required for a phreatomagmatic origin represent a rare example of voluminous surface water bodies in the Late Amazonian of Mars. Plain Language Summary: Steep‐sided landforms in glacial deposits next to volcanoes are good places to look for evidence that lava and ice interacted. We studied high‐resolution images of a steep‐sided ridge in a glacial deposit on the Pavonis Mons volcano on Mars, and used two of the images to make a 3‐D model of the ridge. The distinctly layered beds of rock that make up the ridge, the depressions in nearby ridges, the evidence that part of the ridge collapsed while it was being built, and the way the slope of the ridge changes with location are very similar to landforms on Earth called "tephra‐dominated tindar". This suggests that the Martian ridge formed in a long‐lived body of liquid water, which have been very uncommon on Mars for the past few hundred million years. Key Points: A steep‐sided ridge in the Pavonis Mons glacial deposits comprises a fractured lower unit overlain by layers dipping away from the crestIts steepness and layering are similar to effusion‐dominated tuyas and tephra‐dominated tindar. Morphology and context favor the latterThis implies substantial ice melting and that liquid water remained to interact with the growing edifice, unusual for late Amazonian Mars [ABSTRACT FROM AUTHOR]

Frozen water bodies provide a physiological challenge to fauna by physically limiting access to atmospheric oxygen. To tolerate low temperatures, reptiles use brumation as a physiological strategy in winter. Cryptodira vary in their tolerance to freezing conditions but the extent of tolerance in pleurodirans is largely unknown. Australia's freshwater turtles inhabit warmer regions with less severe winters and have well‐developed mechanisms to cope with high temperatures and drying waterbodies, rather than extreme cold tolerance. Chelodina longicollis is a widespread Australian freshwater turtle species that tolerates high temperatures and desiccation during hot, dry periods while also undergoing brumation during winter months. Despite extensive research, limited observations exist on their behaviour during severe winter periods at the extremes of their range. In an 11‐month tracking study, we monitored adult C. longicollis, noting their movements, locations, and temperature weekly. We observed an adult female C. longicollis which, during a seven‐month period within a single creek pool, survived brumation in extreme cold water including a 15‐day period of total freezing of the surface water. After the ice melted following a rain event, the turtle was recaptured alive. This marks the first observation of brumation for an Australian chelid species under ice. [ABSTRACT FROM AUTHOR]

The Arabian Sea (AS) hosts the world's thickest and most intense oxygen minimum zone (OMZ), and previous studies have documented a dramatic decline of dissolved oxygen (DO) in the northeastern AS in recent decades. In this study, using the recently released data from Biogeochemical‐Argo floats, we found a surprising trend of recovery in deoxygenation within the core region of the OMZ in the AS (ASOMZ) since 2013. The average DO concentration increased by approximately threefold, from ∼0.63 μM in 2013 to ∼1.68 μM in 2022, and the thickness of the ASOMZ decreased by 13%. We find that the weakening of Oman upwelling resulting from the weakening of the summer monsoon is the main driver of oxygenation in the ASOMZ. In addition, the reduction of primary production linked to warming‐driven stratification reinforces deoxygenation recovery at depth. Plain Language Summary: The deoxygenation of the ocean is one of the most important changes occurring in the marine environment, impacting marine biodiversity, primary production, and carbon and nitrogen biogeochemical cycles. Ocean deoxygenation can cause the expansion of naturally occurring low dissolved oxygen (DO) water bodies known as OMZs. As the world's thickest and most intense oxygen minimum zone (OMZ), the Arabian Sea (AS) has undergone a dramatic decrease in DO, particularly in the northeastern AS in recent decades. Based on an unprecedented collection of DO from biogechemical‐Argo floats over the past decade, we found a surprising trend of recovery in deoxygenation within the core region of the OMZ in the AS (ASOMZ) since 2013. The average DO concentration in the ASOMZ increased by almost thrice, and the thickness decreased by 13%. Weakening of the summer monsoon over the AS and strengthening of stratification induced by global warming are possible causes for the recovery from deoxygenation. OMZs have major impacts on global carbon and nitrogen cycles. Our findings not only overturn the previous view of the deoxygenation trend in the ASOMZ but also provide valuable insights for projection model studies of global OMZs. Key Points: Deoxygenation in the oxygen minimum zone in the Arabian Sea has been recovered during the past decadeThe decrease in Oman upwelling due to the weakening of the summer monsoon is likely the main mechanism for the increase in dissolved oxygenThe strengthening of stratification in the AS leading to a decrease in production also contributed to the recovery of deoxygenation [ABSTRACT FROM AUTHOR]

In recent years, increased species extinction and habitat loss have significantly reduced biodiversity, posing a serious threat to both nature and human survival. Environmental factors strongly influence bird distribution and diversity. The potential distribution patterns and species richness offer a conservation modeling framework for policymakers to assess the effectiveness of natural protected areas (PAs) and optimize their existing ones. Very few such studies have been published that cover a large and complete taxonomic group with fine resolution at regional scale. Here, using birds as a study group, the maximum entropy model (MaxEnt) was used to analyze the pattern of bird species richness in Jiangsu Province. Using an unparalleled amount of occurrence data, we created species distribution models (SDMs) for 312 bird species to explore emerging diversity patterns at a resolution of 1 km2. The gradient of species richness is steep, decreasing sharply away from water bodies, particularly in the northern part of Jiangsu Province. The migratory status and feeding habits of birds also significantly influence the spatial distribution of avian species richness. This study reveals that the regions with high potential bird species richness are primarily distributed in three areas: the eastern coastal region, the surrounding area of the lower reaches of the Yangtze River, and the surrounding area of Taihu Lake. Compared with species richness hotspots and existing PAs, we found that the majority of hotspots are well‐protected. However, only a small portion of the regions, such as coastal areas of Sheyang County in Yancheng City, as well as some regions along the Yangtze River in Nanjing and Zhenjiang, currently have relatively weak protection. Using stacked SDMs, our study reveals effective insights into diversity patterns, directly informing conservation policies and contributing to macroecological research advancements. [ABSTRACT FROM AUTHOR]

We assess the accuracy and spatial resolution of the surface water and ocean topography (SWOT) swath altimeter for deriving marine gravity anomalies. The analysis is performed at the Foundation Seamounts in the South Pacific where we developed a highly accurate gravity field by combining the long‐wavelength (>40 km) gravity field derived from previous nadir altimeters with the shorter wavelength gravity field from the seafloor topography as constrained by the ship gravity. In this region, the sea surface slope (SSS) of the ocean variability is 50–100 times smaller than the slope signal of the seamounts so can be ignored in the analysis. Each SWOT cycle can deliver SSS accurately with a standard deviation of 2.6 µrad and a spatial resolution of 14 km at typical sea state (significant wave height 4 m), with accuracy diminishing at high significant wave heights (e.g., exceeds 6 m). Averaging repeated SWOT measurements improves the accuracy and resolution. For example, we expect that averaging just 10 repeats (7 months) results in accuracy/resolution that matches the best marine gravity maps based on 230 months of nadir altimetry. With a mission lasting over a year, SWOT promises a substantial leap in marine gravity accuracy and resolution, uncovering previously uncharted details of the seafloor, including thousands of uncharted seamounts. Plain Language Summary: The surface water and ocean topography (SWOT) is a satellite mission designed to measure Earth's water body heights in wide‐swath, offering opportunities to measure the ocean surface in unprecedented details. This capability brings valuable high‐resolution information about the gravity field and seafloor underneath the ocean. This study aims to evaluate SWOT's performance and our test area is in the South Pacific Ocean where we already know the ocean topography and gravity field well. Results show that with SWOT global measurements lasting over 1 year, it promises a significant improvement in uncharted details of the seafloor. Key Points: A single cycle of surface water and ocean topography (SWOT) at a typical significant wave height of 4 m, has an accuracy of 2.6 μrad and a spatial resolution of 14 kmA stack of ∼60 cycles of SWOT data provides a significant improvement in accuracy to ∼1.2 μrad and spatial resolution ∼8 kmThe accuracy and resolution of the marine gravity field derived from SWOT will exceed current models after 8 months [ABSTRACT FROM AUTHOR]

A fraction of CO2 uptake by terrestrial ecosystems is exported as organic carbon (C) through the terrestrial‐aquatic continuum. This translocated C plays a significant role in the terrestrial C balance; however, obtaining global assessments remains challenging due to the predominant reliance on empirical approaches. Leaching of dissolved organic C (DOC) from soils to rivers represents an important fraction of this C export and is assumed to drive a large proportion of the net‐heterotrophy of river systems and the related CO2 emissions. Using the model JULES‐DOCM, we projected DOC leaching trends over the 21st century based on three scenarios with high (RCP 2.6), intermediate (RCP 4.5), and low (RCP 8.5) climate mitigation efforts. The RCP 8.5 scenario led to the largest DOC leaching increase of +42% to 395 Tg C yr−1 by 2100. In comparison, RCP 2.6 and RCP 4.5 led to increases of 10% and 21%, respectively. Under RCP 8.5, the sub‐tropical zone showed the highest relative increase of 50% above current levels. In the boreal and tropical zones, the simulations revealed similar increases of 48% and 41%, respectively. However, given the pre‐eminence of the tropics in DOC leaching, the absolute increment is markedly substantial from this region (+59 Tg C yr−1). The temperate zone displayed the lowest relative increase with 35%. Our analysis identified the rising atmospheric CO2 concentration and its fertilizing effect on terrestrial NPP as the main reason for the future increase in DOC leaching. Plain Language Summary: Terrestrial ecosystems absorb CO2 and some of this is transformed into dissolved organic carbon (DOC) that leaches from soils to inland waters, driving aquatic CO2 emissions. Using the JULES‐DOCM model, we analyzed future DOC leaching trends under different climate scenarios. The scenario of low climate change mitigation led to the most significant leaching increase by the end of the century. Among various regions, the sub‐tropical areas showed the greatest relative growth in DOC leaching, with the tropics also seeing a substantial rise. This increase in DOC leaching is mainly driven by rising atmospheric CO2 levels, which boosts plant growth and productivity on land. Key Points: We predict an increase of global soil dissolved organic carbon (DOC) leaching of up to 42% or 395 Tg C yr−1 by 2100The sub‐tropical zone experienced the greatest relative DOC leaching growth, while the tropics had a notable absolute increaseThe primary driver for the future surge in DOC leaching is the rising atmospheric CO2 and its fertilizing effect on terrestrial NPP [ABSTRACT FROM AUTHOR]

Less than a year after the 2018 Kīlauea caldera collapse and eruption, water appeared in newly deepened Halemaʻumaʻu crater. The lake—unprecedented in the written record—grew to a depth of ∼50 m before lava from the December 2020 eruption boiled it away. Surface water heightened concerns of potential phreatic or phreatomagmatic explosions but also offered a new means of possibly identifying eruption precursors. The U.S. Geological Survey Hawaiian Volcano Observatory (HVO) monitored the lake via direct visual observation, webcams, thermal imaging, colorimetry, and laser rangefinders. HVO also employed uncrewed aircraft systems to sample the water and measure near‐lake gas composition. The lake's δD and δ18O indicate a groundwater source with substantial evaporation. The initial sample had a salinity (total dissolved solids concentration) of 71,000 mg/L and was rich in sulfate (∼53,000 mg/L), iron (∼500 mg/L), and magnesium (∼10,000 mg/L). Subsequent samples were slightly more dilute. The water's pH (∼4), δ34S (+4.3‰), and surface temperatures (up to 85°C) suggest, rather than significant scrubbing of magmatic volatiles, leaching of basalt and reactions with sulfate minerals resulted in high concentrations of sulfate and other solutes. Thermodynamic modeling and precipitate mineralogy indicate that water composition was controlled by iron oxidation and sulfate dissolution. Although the lake exhibited no detectable precursors before the next eruption, and phreatic or phreatomagmatic explosions did not materialize, our multi‐parameter approach to monitoring yielded an enhanced understanding of the hydrologic, geologic, and magmatic conditions that led to the formation of the unique and short‐lived lake. Plain Language Summary: In 2019, ponded water was spotted within Kīlauea Volcano's summit crater—the first water body in the crater in written history. The presence of a crater lake was important, as it increased the chance of hazardous, explosive eruptions once Kīlauea resumed eruptive activity. However, the lake provided a new way to keep an eye on Kīlauea; other volcanic lakes have changed temperature, color, or chemistry, or even boiled away, before eruptions. We monitored Kīlauea's lake with various methods, including water sampling via drone. Data showed that the lake was fed by groundwater, not rainwater; the lake was acidic, but less so than most acid volcanic lakes; and the lake was not absorbing large amounts of volcanic gas directly. Instead, the lake's chemistry was controlled by reactions with rocks and sulfur‐bearing minerals in and near the crater. Ultimately, no changes to the lake were detected before the next eruption, most likely because of the nature of magma at Kīlauea, which is different from that at most volcanoes with crater lakes. The water lake also did not cause the eruption to be explosive, as lava merely flowed into the lake from above rather than being injected vigorously into the lake from beneath. Key Points: Kīlauea Volcano's summit water lake was sampled three times to track any potential geochemical precursors to eruptionThe lake was fed by groundwater and its chemistry was controlled by leaching of host basalt, iron oxidation, and sulfate dissolutionNo precursory changes to the lake or phreatic activity occurred, likely owing to the nature of basaltic magma and eventual dike location [ABSTRACT FROM AUTHOR]

Bedded gypsum is relatively common in bedded evaporites associated with red bed siliciclastics of Permo‐Triassic Pangea. However, little attention has been paid to the textures of ancient gypsum, which can be used to refine interpretations of depositional environment and diagenetic history. This project describes the textures of bedded gypsum from an outcrop of the Triassic Red Peak Formation (Chugwater Group) near Greybull, Wyoming. Fieldwork, petrography and X‐ray diffraction reveal three distinct lithologies of bedded gypsum: bottom‐growth gypsum, laminated gypsum and clastic gypsum. Bottom‐growth gypsum precipitated at the bottom of shallow saline surface water bodies. Laminated gypsum probably formed in shallow saline lakes and mudflats. Clastic gypsum units are composed of aeolian‐reworked bottom‐growth gypsum crystals deposited in sandflats. Red siliciclastic mudstones are characterised by their massive nature and abundant blocky peds. Detailed study of this outcrop of the Red Peak Formation shows that it formed in shallow saline lakes and associated mudflats, sandflats and desert soils. [ABSTRACT FROM AUTHOR]

Cyanobacterial harmful algal blooms (cyanoHABs) can harm people, animals, and affect consumptive and recreational use of inland waters. Monitoring cyanoHABs is often limited. However, chlorophyll‐a (chl‐a) is a common water quality metric and has been shown to have a relationship with cyanobacteria. The World Health Organization (WHO) recently updated their previous 1999 cyanoHAB guidance values (GVs) to be more practical by basing the GVs on chl‐a concentration rather than cyanobacterial counts. This creates an opportunity for widespread cyanoHAB monitoring based on chl‐a proxies, with satellite remote sensing (SRS) being a potentially powerful tool. We used Sentinel‐2 (S2) and Sentinel‐3 (S3) to map chl‐a and cyanobacteria, respectively, classified chl‐a values according to WHO GVs, and then compared them to cyanotoxin advisories issued by the California Department of Water Resources (DWR) at San Luis Reservoir, key infrastructure in California's water system. We found reasonably high rates of total agreement between advisories by DWR and SRS, however rates of agreement varied for S2 based on algorithm. Total agreement was 83% for S3, and 52%–79% for S2. False positive and false negative rates for S3 were 12% and 23%, respectively. S2 had 12%–80% false positive rate and 0%–38% false negative rate, depending on algorithm. Using SRS‐based chl‐a GVs as an early indicator for possible exposure advisories and as a trigger for in situ sampling may be effective to improve public health warnings. Implementing SRS for cyanoHAB monitoring could fill temporal data gaps and provide greater spatial information not available from in situ measurements alone. Plain Language Summary: Lakes often have algal blooms that create a water quality concern, especially when they contain cyanobacteria, which can be toxic to both humans and animals. These harmful algal blooms are of great concern in areas with limited water supply in states such as California. While it is often difficult and costly to collect and monitor toxin concentrations, monitoring concentrations of chlorophyll‐a (chl‐a) –a measure of how much algae are present—is relatively common and can even be accomplished using satellite remote sensing. There have been multiple studies that have found a relationship between toxins produced by cyanobacteria and chl‐a. The World Health Organization (WHO) has recently released (2021) an updated release of their previous 1999 guidance values for toxin monitoring based on chl‐a concentration. With satellite data, we were able to measure chl‐a concentration in a major reservoir in California, and then classify the chl‐a measurements into the WHO's guidance values for toxins. We compared the satellite‐based guidance values to the public advisory levels currently set by the California Department of Water Resources. Our results indicate that SRS of chl‐a is a reasonable substitute for cyanobacteria toxin advisories, and our framework can be applied to similar cyanobacteria dominated lakes. Key Points: The World Health Organization (WHO) updated cyanobacteria harmful algal blooms (cyanoHABs) guidelines for chlorophyll‐a (chl‐a) as a proxyWith satellite remote sensing (SRS), we estimated and classified chl‐a to compare cyanotoxins advisories used by CaliforniaThis study provides a framework for evaluating public health utility of SRS for enhancing cyanotoxin monitoring globally [ABSTRACT FROM AUTHOR]