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At least 19 recordsLinked to original sources
USGS2022

Daily surface temperatures for 185,549 lakes in the conterminous United States estimated using deep learning (1980–2020)

The dataset described here includes estimates of historical (1980–2020) daily surface water temperature, lake metadata, and daily weather conditions for lakes bigger than 4 ha in the conterminous United States ( n = 185,549), and also in situ temperature observations for a subset of lakes ( n = 12,227). Estimates were generated using a long short-term memory deep learning model and compared to existing process-based and linear regression models. Model training was optimized for prediction on unmonitored lakes through cross-validation that held out lakes to assess generalizability and estimate error. On the held-out lakes with in situ observations, median lake-specific error was 1.24°C, and the overall root mean squared error was 1.61°C. This dataset increases the number of lakes with daily temperature predictions when compared to existing datasets, as well as substantially improves predictive accuracy compared to a prior empirical model and a debiased process-based approach (2.01°C and 1.79°C median error, respectively).

Limnology & Oceanography: Letters↗
USGS2026

The Zooplankton International Geospatial (ZIG) dataset: A global repository of spatiotemporal freshwater zooplankton community composition data from lakes and reservoirs to support ecological research

Zooplankton transfer substantial energy in aquatic food webs and are used as indicators of environmental change. Syntheses of zooplankton community dynamics globally require datasets that span a wide range of environmental gradients; however, these datasets are limited due to methodological differences across programs, taxonomic inconsistencies, and a lack of standardized metadata. To reconcile these challenges, we created the Zooplankton International Geospatial (ZIG) dataset, which includes original zooplankton, water physical and chemical variables, and lake morphometric data from 311 inland lakes and reservoirs. ZIG includes waterbodies ranging in size from 0.005 to 82,100 km 2 and spanning broad latitudinal (−47.26 to 64.90) and longitudinal ranges (−165.04 to 176.53). Temporal coverage for individual waterbodies ranges between 1 and 60 yr with sampling frequency ranging from annually to weekly. With its extensive coverage and content, we consider ZIG to be a cornerstone for future investigations of global scale lake biodiversity change.

Limnology & Oceanography - Letters↗
USGS2026

National-scale remotely sensed lake surface temperature in the contiguous United States

Temperature is a master variable in aquatic ecosystems. Despite its importance for ecosystem function, our capacity to measure temperature is often limited to focal systems with intensive in situ measurements or larger systems with readily accessible data from disparate data streams. These limitations are consequential for holistically understanding aquatic ecosystem status and change, especially considering that most lakes globally do not have consistent in situ data. To empower researchers with macroscale surface temperature observations, we present the first remotely sensed lake temperature dataset that includes measurements from Landsat 8 made every ~ 16 d for 137,394 lakes of at least 4 ha in surface area throughout the contiguous United States from 2013 through 2025. By aggregating data in a cloud computing framework, the dataset is amenable for continual update, thereby allowing end users to track local-to-continental scale changes in lake water temperature over time.

contiguous United States↗
USGS2026

Whatever it takes— Shaping the L&O Letters Early Career Publication Honor to deliver true benefit

There are clear advantages for those who openly share their research. Publishing Open Access (OA) articles can increase author visibility (McCabe and Snyder 2014 ), improve productivity metrics (i.e., more diverse and higher citation rates; Huang et al. 2024 ; Piwowar et al. 2018 ), widen collaborative networks (Tai and Robinson 2018 ), and help secure future funding and/or comply with funder mandates (Herrmannova et al. 2019 ; Larivière and Sugimoto 2018 ; McKiernan et al. 2016 and references therein). These benefits can be vital for students and early career researchers (ECRs) trying to advance and thrive in academia. However, publishing papers in Gold OA journals such as L&O Letters comes at a notable financial cost, as these journals require that the corresponding author (or their organization or funder) pay a fee to make their published article immediately freely available to the public. These article processing charges can be prohibitively expensive (Fontúrbel and Vizentin-Bugoni 2021 ; Mekonnen et al. 2022 ; Ross-Hellauer et al. 2022 ). While Read and Publish agreements and waiver programs may be available to help cover these costs, these programs often exclude independent authors as well as those affiliated with ineligible or non-participating institutions (e.g., publisher waivers using the Research4Life eligibility criteria for access currently only allow authors from one of 13 South American countries/territories to publish free of charge). Besides the financial barrier, authors from underrepresented groups can also face a myriad of other publishing roadblocks, such as linguistic challenges (for speakers of English as a foreign language; Amano et al. 2023 ; Franco-Santos 2024 ; Ramírez-Castañeda 2020 ) and geopolitical-scientific bias (e.g., science conducted in the Global South being seen as less impactful and innovative than that conducted in the Global North; Ghosh 2022 ; Smits et al. 2025 ). For context, Global South (GS) and Global North (GN) are not geographic determinations (i.e., South and North hemispheres), but geopolitical classifications regarding a nation's level of development (underdeveloped, developing, or developed). For example: Australia and Brazil are both located in the southern hemisphere, but the former is considered as a Global North (developed) country and the latter as a Global South (underdeveloped or developing) country. When a subset of researchers is unable to openly publish their work, the diversity of voices represented in OA literature can decline (Williams et al. 2023 ). Loss of diversity is a loss to science, as diversity increases productivity, innovation, and scientific impact (refer to opening quote; Freeman and Huang 2014 ; AlShebli et al. 2018 ; Tomillo et al. 2022 ). To partially address the above-mentioned challenges and enable underfunded ECRs to publish their work in OA format, the biennial L&O Letters Early Career Publication Honor (ECPH) was established in 2020 by the ASLO Raelyn Cole Editorial (RCE) Fellows (Hotaling et al. 2022 ). Below we reflect on the benefits, outcomes, and scientific impact of the 2022 call and introduce the articles it helped publish in L&O Letters , which are bundled in this section of the ECPH Virtual Issue. Articles published in L&O Letters during other calls are available in their respective sections. We also refer the reader to six articles published by ECRs in other journals (not included in this Virtual Issue) whose content originally warranted their leading author an ECPH in 2022.

Limnology and Oceanography Letters↗
USGS2023

Validity of the Landsat surface reflectance archive for aquatic science: Implications for cloud-based analysis

Originally developed for terrestrial science and applications, the US Geological Survey Landsat surface reflectance (SR) archive spanning ~ 40 yr of observations has been increasingly utilized in large-scale water-quality studies. These products, however, have not been rigorously validated using in situ measured reflectance. This letter quantifies and demonstrates the quality of the SR products by harnessing a sizeable global dataset ( N = 1100). We found that the Landsat 8/9 SR in the green and red bands marginally meet the targeted accuracy requirements (30%), whereas the uncertainties in the blue and coastal-aerosol bands ranged from 48% to 110%. We further observed > +25% biases in the visible bands of Landsat 5/7 SR, which can introduce an apparent downward trend when applied in time-series analyses combined with Landsat 8/9. Users must exercise caution when using this archive for trend analyses, and progress in atmospheric correction is required to foster advanced applications of the Landsat archive for aquatic science.

Limnology and Oceanography Letters↗
USGS2016

Climate-induced warming of lakes can be either amplified or suppressed by trends in water clarity

Climate change is rapidly warming aquatic ecosystems including lakes and reservoirs. However, variability in lake characteristics can modulate how lakes respond to climate. Water clarity is especially important both because it influences the depth range over which heat is absorbed, and because it is changing in many lakes. Here, we show that simulated long-term water clarity trends influence how both surface and bottom water temperatures of lakes and reservoirs respond to climate change. Clarity changes can either amplify or suppress climate-induced warming, depending on lake depth and the direction of clarity change. Using a process-based model to simulate 1894 north temperate lakes from 1979 to 2012, we show that a scenario of decreasing clarity at a conservative yet widely observed rate of 0.92% yr −1 warmed surface waters and cooled bottom waters at rates comparable in magnitude to climate-induced warming. For lakes deeper than 6.5 m, decreasing clarity was sufficient to fully offset the effects of climate-induced warming on median whole-lake mean temperatures. Conversely, a scenario increasing clarity at the same rate cooled surface waters and warmed bottom waters relative to baseline warming rates. Furthermore, in 43% of lakes, increasing clarity more than doubled baseline bottom temperature warming rates. Long-term empirical observations of water temperature in lakes with and without clarity trends support these simulation results. Together, these results demonstrate that water clarity trends may be as important as rising air temperatures in determining how waterbodies respond to climate change.

Limnology and Oceanography Letters↗
USGS2017

Ice duration drives winter nitrate accumulation in north temperate lakes

The duration of winter ice cover on lakes varies substantially with climate variability, and has decreased over the last several decades in many temperate lakes. However, little is known of how changes in seasonal ice cover may affect biogeochemical processes under ice. We examined winter nitrogen (N) dynamics under ice using a 30+ yr dataset from five oligotrophic/mesotrophic north temperate lakes to determine how changes in inorganic N species varied with ice duration. Nitrate accumulated during winter and was strongly related to the number of days since ice-on. Exogenous inputs accounted for less than 3% of nitrate accumulation in four of the five lakes, suggesting a paramount role of nitrification in regulating N transformation and the timing of chemical conditions under ice. Winter nitrate accumulation rates ranged from 0.15 μ g N L −1 d −1 to 2.7 μ g N L −1 d −1 (0.011–0.19 μ M d −1 ), and the mean for intermediate depths was 0.94 μ g N L −1 d −1 (0.067 μ M d −1 ). Given that winters with shorter ice duration (< 120 d) have become more frequent in these lakes since the late 1990s, peak winter nitrate concentrations and cumulative nitrate production under ice may be declining. As ice extent and duration change, the physical and chemical conditions supporting life will shift. This research suggests we may expect changes in the form and amount of inorganic N, and altered dissolved nitrogen : phosphorus ratios, in lakes during winters with shorter ice duration.

Limnology and Oceanography Letters↗
USGS2019

Microplastic concentrations in two Oregon bivalve species: Spatial, temporal, and species variability

Microplastics are an ecological stressor with implications for ecosystem and human health when present in seafood. We quantified microplastic types, concentrations, anatomical burdens, geographic distribution, and temporal differences in Pacific oysters ( Crassostrea gigas ) and Pacific razor clams ( Siliqua patula ) from 15 Oregon coast, U.S.A. sites. Microplastics were present in organisms from all sites. On average, whole oysters and razor clams contained 10.95 ± 0.77 and 8.84 ± 0.45 microplastic pieces per individual, or 0.35 ± 0.04 pieces g −1 tissue and 0.16 ± 0.02 pieces g −1 tissue, respectively. Contamination was quantified but not subtracted. Over 99% of microplastics were fibers. Material type was determined using Fourier‐transform infrared spectroscopy. Spring samples contained more microplastics than summer samples in oysters but not razor clams. Our study is the first to document microplastics in Pacific razor clams and provides important coast‐wide data to compare microplastic burden across species, seasons, and sites.

Oregon↗
USGS2019

Increasing accuracy of lake nutrient predictions in thousands of lakes by leveraging water clarity data

Aquatic scientists require robust, accurate information about nutrient concentrations and indicators of algal biomass in unsampled lakes in order to understand and predict the effects of global climate and land-use change. Historically, lake and landscape characteristics have been used as predictor variables in regression models to generate nutrient predictions, but often with significant uncertainty. An alternative approach to improve predictions is to leverage the observed relationship between water clarity and nutrients, which is possible because water clarity is more commonly measured than lake nutrients. We used a joint-nutrient model that conditioned predictions of total phosphorus, nitrogen, and chlorophyll a on observed water clarity. Our results demonstrated substantial reductions (8–27%; median = 23%) in prediction error when conditioning on water clarity. These models will provide new opportunities for predicting nutrient concentrations of unsampled lakes across broad spatial scales with reduced uncertainty.

Limnology and Oceanography Letters↗
USGS2020

Thinking like a consumer: Linking aquatic basal metabolism and consumer dynamics

The increasing availability of high‐frequency freshwater ecosystem metabolism data provides an opportunity to identify links between metabolic regimes, as gross primary production and ecosystem respiration patterns, and consumer energetics with the potential to improve our current understanding of consumer dynamics (e.g., population dynamics, community structure, trophic interactions). We describe a conceptual framework linking metabolic regimes of flowing waters with consumer community dynamics. We use this framework to identify three emerging research needs: (1) quantifying the linkage of metabolism and consumer production data via food web theory and carbon use efficiencies, (2) evaluating the roles of metabolic dynamics and other environmental regimes (e.g., hydrology, light) in consumer dynamics, and (3) determining the degree to which metabolic regimes influence the evolution of consumer traits and phenology. Addressing these needs will improve the understanding of consumer biomass and production patterns as metabolic regimes can be viewed as an emergent property of food webs.

Limnology and Oceanography Letters↗
USGS2022

Reconciling models and measurements of marsh vulnerability to sea level rise

Tidal marsh survival in the face of sea level rise (SLR) and declining sediment supply often depends on the ability of marshes to build soil vertically. However, numerical models typically predict survival under rates of SLR that far exceed field-based measurements of vertical accretion. Here, we combine novel measurements from seven U.S. Atlantic Coast marshes and data from 70 additional marshes from around the world to illustrate that—over continental scales—70% of variability in marsh accretion rates can be explained by suspended sediment concentratin (SSC) and spring tidal range (TR). Apparent discrepancies between models and measurements can be explained by differing responses in high marshes and low marshes, the latter of which accretes faster for a given SSC and TR. Together these results help bridge the gap between models and measurements, and reinforce the paradigm that sediment supply is the key determinant of wetland vulnerability at continental scales.

Limnology and Oceanography Letters↗
USGS2022

Classifying freshwater salinity regimes in central and western U.S. streams and rivers

Freshwater salinization of rivers is occurring across the globe because of nonpoint source loading of salts from anthropogenic activities such as agriculture, urbanization, and resource extraction that accelerate weathering and release salts. Multidecadal trends in river salinity are well characterized, yet our understanding of annual regimes of salinity in rivers draining diverse central and western U.S. landscapes and their associated catchment attributes is limited. We classified annual salinity regimes in 242 stream locations through dynamic time warping and fuzzy c-medoids clustering of salinity time series. We found two dominant regimes in salinity characterized by an annual summer–fall peak or spring decline . Using random forest regression, we found that precipitation amount, stream slope, and soil salinity were the most important predictors of salinity regime classification. Advancing our understanding of salinity regimes in rivers will improve our ability to predict and mitigate the effects of salinization in freshwater ecosystems through management interventions.

Limnology and Oceanography Letters↗
USGS2022

Early career researchers have questions about peer review—we asked the ASLO editors for answers

Peer review is the formal means by which the scientific community assesses the originality, reproducibility, validity, and quality of a research study (Bakker and Traniello 2019). As such, peer review assures nonexperts that they can trust a study's findings (Jamieson et al. 2019). Despite the critical importance of peer review, graduate students, postdocs, and other early career researchers (ECRs) have limited resources for learning about this process (but see Nicholas and Gordon 2011 and Nature Communications 2021). A recent survey found that most reviewers have not received formal training on peer review and that reviewers of all career stages (77%), especially ECRs (89%), desire further training (Warne 2016). This reflects a need for guidance regarding when and how to engage in peer review, best practices for conducting a peer review, and how editors weigh peer reviews in their editorial decisions. In an effort to help new reviewers navigate this process, we (the Raelyn Cole Editorial Fellows) hosted an Association for the Sciences of Limnology and Oceanography (ASLO) webinar on peer review in September of 2021 (recording available: https://www.youtube.com/watch?v=utntl1VGy5g). The webinar had 329 registrants, including 198 students or postdocs, underscoring the desire for peer review resources. The webinar content was largely based on a survey of the associate editors (AEs) of ASLO's three peer-reviewed journals ( n = 25 respondents), consisting of five open-ended questions about peer review. Here, we use insights from our survey and webinar to describe how ECRs can join the reviewer pool, provide guidance for writing a useful and time-efficient review, and discuss challenges and opportunities in the evolving landscape of peer review.

Limnology and Oceanography Letters↗
USGS2022

Variability in marsh migration potential determined by topographic rather than anthropogenic constraints in the Chesapeake Bay region

Sea level rise (SLR) and saltwater intrusion are driving inland shifts in coastal ecosystems. Here, we make high-resolution (1 m) predictions of land conversion under future SLR scenarios in 81 watersheds surrounding Chesapeake Bay, United States, a hotspot for accelerated SLR and saltwater intrusion. We find that 1050–3748 km 2 of marsh could be created by 2100, largely at the expense of forested wetlands. Predicted marsh migration exceeds total current tidal marsh area and is ~ 4× greater than historical observations. Anthropogenic land use in marsh migration areas is concentrated within a few watersheds and minimally impacts calculated metrics of marsh resilience. Despite regional marsh area maintenance, local ecosystem service replacement within vulnerable watersheds remains uncertain. However, our work suggests that topography rather than land use drives spatial variability in wetland vulnerability regionally, and that rural land conversion is needed to compensate for extensive areal losses on heavily developed coasts globally.

Delaware, Maryland, Virginia↗
USGS2022

Taking steps to address inequities in open-access publishing through an early career publication honor

Access to resources—whether human, financial, or social—is a key indicator of research output and, in turn, academic career progression. However, resources are not equally distributed among scientists and disparities often stem from external factors. This reality is particularly impactful for early career researchers (ECRs) who have limited control over the resources available to them to advance their careers. The resources needed to fund open-access (OA) publishing are a well-known source of academic inequity (Ross-Hellauer 2022 ). Despite this, wide support for OA publishing exists across the scientific community, largely because OA articles increase access to the scientific literature by removing costly paywalls (Piwowar et al. 2018 ). Benefits of OA publishing also exist for individual researchers; OA studies are read and cited more, so much so that an “open access citation advantage” has been described (McCabe and Snyder 2014 ). Depending on the methods and journals studied, this advantage ranges from an 8 to 40% increase in citation rate (Piwowar et al. 2018 ). The OA publishing model is set to expand further, with influential groups seeking to mandate OA publishing (e.g., Plan S; Else 2021 ) including recent guidance from the United States Office of Science and Technology Policy (The White House 2022 ). However, OA publishing remains expensive, often prohibitively so, and OA fees deter ECRs broadly (Sarabipour et al. 2019 ), and particularly those from the Global South (Kwon 2022 ; Santidrián Tomillo et al. 2022 ).

Limnology and Oceanography Letters↗
USGS2022

Extent, patterns, and drivers of hypoxia in the world's streams and rivers

Hypoxia in coastal waters and lakes is widely recognized as a detrimental environmental issue, yet we lack a comparable understanding of hypoxia in rivers. We investigated controls on hypoxia using 118 million paired observations of dissolved oxygen (DO) concentration and water temperature in over 125,000 locations in rivers from 93 countries. We found hypoxia (DO < 2 mg L −1 ) in 12.6% of all river sites across 53 countries, but no consistent trend in prevalence since 1950. High-frequency data reveal a 3-h median duration of hypoxic events which are most likely to initiate at night. River attributes were better predictors of riverine hypoxia occurrence than watershed land cover, topography, and climate characteristics. Hypoxia was more likely to occur in warmer, smaller, and lower-gradient rivers, particularly those draining urban or wetland land cover. Our findings suggest that riverine hypoxia and the resulting impacts on ecosystems may be more pervasive than previously assumed.

Limnology and Oceanography - Letters↗
USGS2023

Taxonomic identity, biodiversity, and antecedent disturbances shape the dimensional stability of stream invertebrates

The “dimensional stability” approach measures different components of ecological stability to investigate how they are related. Yet, most empirical work has used small-scale and short-term experimental manipulations. Here, we apply this framework to a long-term observational dataset of stream macroinvertebrates sampled between the winter flooding and summer monsoon seasons. We test hypotheses that relate variation among stability metrics across different taxa, the magnitude of antecedent (monsoon) and immediate (winter) floods to stability metrics, and the relative importance of disturbance magnitude and taxonomic richness on community dimensional stability. Cluster analysis revealed four distinct stability types, and we found that the magnitude of floods during the prior monsoon was more important in influencing stability than the winter flood itself. For dimensional stability at the community level, taxonomic richness was more important than disturbance magnitude. This work demonstrates that abiotic and biotic factors determine dimensional stability in a natural ecosystem.

Limnology and Oceanography Letters↗
USGS2023

Over half a century record of limnology data from Lake Powell, desert southwest United States: From reservoir filling to present day (1964–2021)

Lake Powell is a large water storage reservoir in the arid southwestern United States. Here, we present a 58-yr limnology dataset that captures water quality parameters from reservoir filling to present day (temperature, salinity, major ions, total suspended solids), as well as a 38-yr record of Secchi depth, and a ~ 30-yr record of nutrients, phytoplankton, and zooplankton assemblages. The dataset includes 5208 unique site visits spanning 258 unique sites of which 9 have been consistently visited. It also spans the establishment of an invasive bivalve ( Dreissena bugensis, i.e. Quagga mussel) which was first detected in 2012. Given the general lack of long-term data from lakes or reservoirs in arid regions, this dataset represents a unique contribution to regional, continental, and global-scale limnology studies. As the hot drought in the desert southwest continues, we expect this dataset will inform water management decision-making for this largest reservoir in the Upper Colorado River Basin.

Arizona, Utah↗