American River Research Articles

Dental and temporomandibular joint pathology of the North American river otter (Lontra canadensis).

Museum skull specimens from 165 North American river otters (Lontra canadensis) from Alaska, USA, were analysed systematically using an established protocol designed for examination of mammalian dentition. The study population was collected from 1956 to 2012 and comprised a similar proportion of males (n=82, 49.7%) and females (n=72, 43.6%). Eleven animals were of unknown sex. The study group incorporated a higher proportion of skeletally mature adults (n=128, 78.5%) compared to young adults. As with many other mammalian species, the most common types of pathology in this species were periodontitis (n=158, 95.7%), attrition/abrasion (n=160, 92.7%) and tooth fractures (n=87, 52.7%). The North American river otter also had a relatively high prevalence of periapical lesions (n=41, 24.8%) and root number variation (n=98, 59.4%) when compared with other mammalian species. Temporomandibular joint pathology occurred at a similar rate to that of the closely related southern sea otter (Enhydra lutris nereis) but most cases were mild in severity.

Predictive habitat occupancy models for North American river otters along inland streams in New Jersey

The North American river otter Lontra canadensis is a semi‐aquatic furbearer species that historically ranged throughout North America. Starting in the mid‐1800s and continuing through the early 1900s, the negative effects associated with anthropogenic disturbances (i.e. overharvest, development and ultimately habitat alternation) led to local extinctions. Researchers debate whether current land use patterns are affecting river otter occupancy. New Jersey is the most densely populated state in the United States, thus it provides a perfect study area to test potential anthropogenic effects on river otters. Using occupancy modeling to examine river otter habitat preferences, we measured presence/absence at 244 low order streams from January–April 2011–2012 along with 19 corresponding site/landscape covariates in both northern and southern New Jersey. In southern New Jersey, we detected otters at 83/141 sites (58.9%) with a detection probability of 97.7% across repeat visits and a predicted occupancy of 59.4 ± 0.04%. In northern New Jersey we detected otters at 31/103 sites (30.1%) with a detection probability of 44.5% across repeat visits and a predicted occupancy of 58.8 ± 0.04%. We determined the influence of habitat covariates on otter occupancy and found that water depth, water quality, stream width and mink presence were positively correlated with otter occupancy. The % commercial, industrial, transportation and recreational habitat, % low intensity development, bank slope, and distance to lake were negatively correlated with otter occupancy. Knowing the location of occupied stream and latrine sites will assist biologists in their efforts to monitor river otter populations and help estimate river otter density for harvest and conservation efforts.

Optimizing integrated water supply management for multi-purpose reservoirs: a policy tree approach

ABSTRACT Recent changes in the inter and intra-annual water availability, along with the increase in water demand, have heightened the pressure on the world’s limited freshwater resources. The sustainability of the groundwater system is endangered due to prolonged droughts and excessive exploitation of aquifers. This study focuses on the development of a policy tree optimization model for the reoperation of the Folsom reservoir in the American River watershed, California, incorporating floodwaters for managed aquifer recharge (Flood-MAR). Drawing upon a previously developed simulation-optimization model, a policy tree optimization model that incorporated a surrogate model for recharge was formulated for the American River Watershed downstream of Folsom. The model devised a policy tree for the operation of the system, including groundwater recharge policies. It successfully allocated water for recharge while increasing the reservoir’s storage capacity compared to historical operations, suggesting the feasibility of incorporating Flood-MAR into Folsom reservoir operations.

North American river otter habitat suitability and human–wildlife coexistence on Protection Island, British Columbia, Canada

AbstractLand use change and urban sprawl increase the likelihood of encounters between humans and wildlife. North American river otters (Lontra canadensis) coexist (and also conflict) with humans in many places, including on Protection Island, British Columbia, Canada. River otters are sensitive to, yet also inhabit, environments with relatively high levels of anthropogenic disturbance. From June to November 2022, we investigated the effect of anthropogenic factors on river otter use of space and behavior. We modeled the relative importance of anthropogenic (e.g., distance to buildings and roads, level of human use of docks), environmental (e.g., land cover type), and topographic (elevation) variables for habitat suitability in wild river otters on Protection Island using maximum entropy (MaxEnt) species distribution models, from 660 occurrence points collected. We conducted 178 behavioral scan samples (containing 594 observations) from direct‐observation video and motion‐triggered trail camera video to evaluate behavioral differences associated with the use of an anthropogenic habitat feature, docks (a potential attractant), and land. We found that the most suitable areas for river otters in this study were near docks (at all levels of human use), near water or wetlands (within ~25 m of the water), and had intermediate densities of driftwood. Further, our findings indicated that human activities generally did not impede otter use of space — river otters and humans were able to coexist in this semi‐urban context. Behaviors on docks differed from behaviors on land, and river otters used docks more than would be expected by chance overall, and specifically overnight, and used docks for individual and social activities. Our case study suggests that anthropogenic and environmental factors are key habitat suitability predictors for river otters, and that in populations habituated to human presence, docks may act as a habitat attractant. This case can inform conservation and management practices for river otters, other flagship species, and the ecosystems they inhabit, enhancing human–wildlife coexistence in anthropogenic landscapes.

Species diversity in the new lamprey genus Occidentis, formerly classified as western North American ‘Lampetra’

Accurate taxonomy is fundamental to the study and conservation of biodiversity. Because of their morphological similarities, most brook and river lampreys in western North America have been placed in the genus Lampetra along with lampreys from Eurasia and eastern North America. However, molecular-based phylogenetic studies dating back several decades indicate that lampreys from Pacific drainages are genetically distinct from Atlantic Lampetra. Reviewing previous phylogenetic analysis of two mitochondrial and two nuclear genes for Northern Hemisphere lampreys, we assign these western North American brook and river lampreys to a new genus, Occidentis. To assess species diversity within Occidentis, we performed a species delimitation analysis using all publicly available cytochrome b sequences of the genus. Similar to previous studies, O. ayresii and O. richardsoni were not reciprocally monophyletic and are best categorized as life history variants of a single species. In addition to O. pacifica, O. hubbsi, and the diverse O. ayresii species complex, as many as seven undescribed candidate species from Oregon and California were identified, supporting results from previous studies with more geographically limited datasets. One specimen from Paynes Creek, California, was identified as a candidate species, although this single individual showed minimal interspecific divergence (1.34%) with O. hubbsi. Further genetic assessment along with information on morphology and phylogeography is needed to determine whether the variation observed between groups of candidate species represents distinct species or divergent lineages within a species complex. Additional sampling will inform whether there are additional species not currently represented in this dataset. Thus, the number of species formally recognized under Occidentis is subject to change with new information. Systematic assessment of the distribution and phylogenetic complexity within Occidentis will enhance our understanding of its evolutionary history and taxonomic diversity, which will guide efforts to conserve the biodiversity of lampreys.

Enhanced wet grip with North American river otter paws.

The semi-aquatic North American river otter (Lontra canadensis) has the unique challenge of navigating slippery algae-coated rocks. Unlike other river otter species, each rear paw of the North American river otter has a series of soft, circular, and keratinized plantar pads similar to the felt pads on the boots of fly fishermen. Surrounding these soft pads is a textured epidermal layer. In this combined experimental and numerical study, we investigate the influence of the plantar pads and surrounding skin on the otter's grip. We filmed an otter walking and performed materials testingand histology on preserved otter paws. We present experiments and numerical modeling of how the otter paw may help evacuate water when contacting the river bed. We hope this study will draw interest into natural amphibious grip mechanisms for use in sports and the military.

A functional microbiome catalogue crowdsourced from North American rivers.

Predicting elemental cycles and maintaining water quality under increasing anthropogenic influence requiresknowledge of the spatial drivers of river microbiomes. However, understanding of the core microbial processes governing river biogeochemistry is hindered by a lack of genome-resolved functional insights and sampling across multiple rivers. Here we used a community science effort to accelerate the sampling, sequencing and genome-resolved analyses of river microbiomes to create the Genome Resolved Open Watersheds database (GROWdb). GROWdb profiles the identity, distribution, function and expression of microbial genomes across river surface waters covering 90% of United States watersheds. Specifically, GROWdb encompasses microbial lineages from 27 phyla, including novel members from 10 families and 128 genera, and defines the core river microbiome at the genome level. GROWdb analyses coupled to extensive geospatial information reveals local and regional drivers of microbial community structuring, while also presenting foundational hypotheses about ecosystem function. Building on the previously conceived River Continuum Concept1, we layer on microbial functional trait expression, which suggests that the structure and function of river microbiomes is predictable. We make GROWdb available through various collaborative cyberinfrastructures2,3, so that it can be widely accessed across disciplines for watershed predictive modelling and microbiome-based management practices.

Seasonally stable wetted width elucidates freshwater mussel species richness and endangered species presence: implications for T&E management programs and stream restoration design

Centuries of beaver extirpation, deforestation, and other anthropogenic impacts have disconnected North American rivers from their floodplains and concentrated more hydraulic energy within their channels, degrading aquatic habitat and making the streambed more prone to erosion. Rivers naturally adjust via systematic downcutting, bank erosion, channel widening, bar building, and the gradual recovery of geomorphic equilibrium with well‐connected benches that dissipate hydraulic energy and restore a more natural streambed disturbance regime. The life histories of two endangered freshwater mussels, the fanshell (Cyprogenia stegaria) and snuffbox (Epioblasma triquetra), suggest they have evolved to and depend on the natural disturbance regime. Young juveniles excyst from their host fish in early summer, burrow into the top few millimeters of the streambed, and then need ca. 3 months of streambed stability prior to growing large enough to be less vulnerable to streambed mobilization. We propose a conceptual model that suggests a potential prerequisite to supporting fanshell and snuffbox populations is a geomorphically recovering (i.e. at least one stable bank and a wide enough channel corridor for at least partially vegetated bars/benches) or recovered (i.e. stable banks and vegetated benches) channel and floodplain corridor that sufficiently dissipates its hydraulic energy to maintain seasonal streambed stability during typical (non‐hurricane) summer/autumns. To explore this conceptual model, we conducted mussel and geomorphic surveys in a reach of the Rolling Fork River that spanned a range of channel conditions from chronically failing streambanks to a geomorphically recovered channel with wide, vegetated benches. Our analyses documented increasing mussel species richness, including the presence of the endangered fanshell or snuffbox, with increasing width of seasonally stable streambed habitat.

Recovery of the Giant South American River Turtle in four decades of a network-based conservation program in the Brazilian Amazon

Recovery of the Giant South American River Turtle in four decades of a network-based conservation program in the Brazilian Amazon

Lead levels and abundance of microplastics in surface water and sediment along a rural–urban river gradient

Microplastics are commonly found in aquatic ecosystems and can pose environmental threats to aquatic organisms. While the threats of microplastic ubiquity are recognized, few studies have concomitantly quantified microplastic abundance and heavy metals along a rural–urban river continuum. In the current study, we studied changes in microplastics and heavy metals (using lead as a proxy) by collecting sediment and water samples along a rural–urban river over two seasons (temperate spring and summer) and across five sites in a North American River. Our results revealed that microplastics decreased in a downstream direction in surface water but did not change predictably in sediment samples collected along the river continuum. Regarding the relationship between microplastic abundance and lead concentrations, we found a positive relationship between microplastics in sediment samples and lead concentrations. Contrariwise, we found no discernible correlation between microplastics in surface water and lead concentrations along the river continuum. Given the presence of microplastics at every site and moderate lead pollution documented in the Wolf River, our results provide baseline data that can aid in the concurrent assessment of microplastics and heavy metals in river systems. These findings can inform environmental managers in planning pollution management strategies for waterways flowing through rural–urban areas.

Density of Limnoperna fortunei larval stages in a cascade of subtropical reservoirs: spatiotemporal variation and environmental influences.

The golden mussel (Limnoperna fortunei) is an invasive bivalve that has established itself in several South American river systems, impacting ecosystem functioning. Reservoir cascades provide their larvae with the means of rapid dispersal, but the relationship between environmental variables and larval stage structure remains unclear. In this study, the density of three L. fortunei larval stages and quantitative detection using DNA are analyzed in a cascade of five reservoirs in the upper Uruguay River Basin and associated with spatiotemporal variation in environmental parameters. The analysis of L. fortunei eDNA presence and absence in freshwater systems appears to be a valuable mapping tool; however, no significant link was found between the eDNA magnitude and the overall larval density. The increase in larval density was related to the fluctuation of environmental parameters over a year, with the highest average larval densities observed in the CN and ITA reservoirs, though no significant difference was observed between the five reservoirs, where D-shaped larvae predominated. During winter, larval density decreased significantly, however, other variables also contribute to species activity and development in the upper Uruguay River Basin reservoirs and may be considered limiting factors. The relationships between environmental parameters were evaluated using a multivariate model. The interaction between reservoir area and precipitation, water temperature, electrical conductivity, and dissolved oxygen had a significant effect on larval density but showed specific influences on each larval stage. Any increase in density was regulated by dissolved oxygen and electrical conductivity content at all larval stages. Furthermore, total phosphorus affected the density of F1 and F3 larvae. The interaction between reservoir area and precipitation, nitrate content, phosphate concentrations, and water temperature had the most influence on the density of F2 and F3 larval stages; the F1 stage was mainly affected by calcium concentrations. The isolated effect of precipitation also contributed to the density of F2 and F3 larvae. Our findings shed light on the interaction between different phases of golden mussel larvae and the main nutrients found in reservoirs, which may be a determining factor in the rise in density of the non-native species in these systems.

Reconstructing 169 years of historical atmospheric and hydrologic conditions in the American River Watershed through the Watershed Environmental Hydrology Hydro-Climate Model system

The risk of more frequent and intensified extreme events is expected to increase with climate change. In semi-arid regions, particularly, both increased flooding and prolonged droughts pose a threat as the water resources system must be prepared for both types of extremes. To understand how future extremes may be altered, however, past extremes must be understood. For this reason, this study employs three physically based models to simulate the atmospheric, snow, and hydrologic conditions in the American River Watershed: the Weather Research and Forecasting Model and the Watershed Environmental Hydrology Hydro-Climate Model with the addition of a SNOW Module. Each model is individually calibrated and validated against either gauge data or data provided by the Parameter-Elevation Regressions on Independent Slopes Model for two 10-year periods before a full 169-year daily reconstruction is performed for the period from 1852 through 2020. To analyze the model performance under hydrologic extremes, three flood years (1997, 2006, and 2017) and two drought periods (1987–1992 and 2012–2016) are further analyzed. The reconstruction outputs are found to successfully simulate historical conditions at both daily and monthly scales. Results highlight the importance of fully accounting for the role of temperature in snow processes and the subsequent flow conditions. By understanding how the models perform under historical extreme conditions, future extreme events can be compared, and necessary adaptation plans can be conceived to ensure that the watershed is prepared for future wet and dry conditions. Additionally, the created reconstruction dataset is comprehensive, simulating conditions across the hydroclimate, at a finer spatial and temporal scale than is typically available from observation data alone. The dataset can be further analyzed to assess changes in the trends and the potential trajectory of extreme events within the American River Watershed.

Assessing the Diet of the Elusive North American River Otter (Lontra canadensis) in Florida Using Faecal DNA Metabarcoding

ABSTRACTNorth American river otters (Lontra canadensis) are semiaquatic mammals distributed throughout the North American continent. They are generalist carnivores with a high potential to affect community structure and dynamics. However, habitat degradation and ecosystem changes have the potential to impact their trophic interactions. Therefore, investigating their diet is critical to understand how anthropogenic disturbances can affect their ecological roles, particularly in the urbanised ecosystems in Florida, where such diet information is currently unavailable. Due to their elusive nature, direct observation of feeding events is a major challenge. Here, we have applied DNA metabarcoding of faecal matter (fDNA), opportunistically collected from river otters killed by road traffic in eastern Florida. Two mitochondrial markers were used to identify prey species' DNA—one for fish and one for vertebrates. A total of 23 unique exact sequence variants (ESVs) were identified, the majority belonging not only to teleosts but also to amphibians, reptiles, birds and mammals. The prey species identified are known dietary resources for river otters and the recovered dietary profiles provided independently by the fish and vertebrate assays were similar. Among the identified teleost prey, three fish species are considered invasive. Here, we show that when sufficient reference sequences are available, fDNA metabarcoding provides high prey species resolution. The collection and metabarcoding of faecal samples is particularly advantageous for scaling diet studies, both geographically and longitudinally, highlighting the potential of fDNA metabarcoding for the investigation of the diet of predators. This can provide foundational information on the organisation of ecological networks, which is vital for implementing successful ecosystem‐based conservation management.

Contaminant Exposure and Liver and Kidney Lesions in North American River Otters in the Indian River Lagoon, Florida.

The harmful algal bloom (HAB) liver toxin microcystin (MC) and trace element biomagnification were previously detected in organisms in the Indian River Lagoon (IRL), Florida. Since there are no routine screening programs for these contaminants, liver tissue from North American river otters (Lontra canadensis), an important sentinel species in the IRL, was screened for MC via enzyme-linked immunoassay (ELISA), followed by confirmatory analyses via liquid-chromatography/mass spectrometry methods (LC-MS/MS). Liver and kidney samples were evaluated for trace element (As, Cd, Co, Cu, Fe, Hg, Mn, Mo, Pb, Se, Tl, and Zn) bioaccumulation via inductively coupled plasma mass spectrometry (ICP-MS). Histopathologic evaluation of the liver and kidney was conducted to assess possible correlation with toxic insults. Forty-three river otters were evaluated (2016-2022). Microcystin was not detected in any river otter sample (n = 37). Of those tested for trace element bioaccumulation (n = 22), no sample measured above provided reference ranges or estimated toxic thresholds for this species. There were no statistically significant patterns observed based on season, year, or age class, but sex had a small influence on trace element levels in the kidney. One individual had a kidney Cu level (52 μg/g dry weight) higher than any previously reported for this species. Trace elements were detected at presumed background levels providing baselines for future monitoring. For otters with available histopathologic evaluation (n = 28), anomalies indicative of contaminant exposure (non-specific inflammation, necrosis, and/or lipidosis) were present in the liver and kidney of 18% and 4% of individuals, respectively. However, since these lesions were not linked to abnormal trace element bioaccumulation or MC exposure, other causes (e.g., infectious disease) should be considered.

Elemental composition and potential toxicity of the riverine macrophyte Podostemum ceratophyllum Michx. reflects land use in eastern North America

Land use influences surface water quality, often alleviating stoichiometric constraints on primary production and altering biogeochemical cycling. However, land use effects on nutrient content and potential trace metal accumulation in aquatic plants remain unclear, and high concentrations of metals and altered nutrient ratios could impact the health of herbivores and detritivores. We tested for land use effects on nutrient and trace metal accumulation in a widespread riverine macrophyte, Podostemum ceratophyllum, collected from 91 locations from Georgia to Maine, USA in 2014-2016. We quantified carbon (C), nitrogen (N), phosphorus (P), their molar and mass ratios, N and C stable isotopes, and 17 additional elements in dried plants collected from each location to estimate relationships between plant tissue content and watershed land use, which we quantified as agriculture, forest, and development. Decreasing forest cover was correlated with increasing δ15N, Mg, Mn, and P in Podostemum tissue. Increasing urban development was correlated with increasing δ15N, Mg and P, while increasing agriculture was correlated with a decrease in C: P and the concentrations of multiple metals, along with increases in P, Mg and δ15N. Decreases in ratios of N: P and C:P with increasing agriculture and urban development in the watershed indicate more rapid P storage relative to C and N in plant tissue, and increased resource quality of the plant to consumers in these watersheds. We also observed potentially toxic dietary concentrations of some trace metals (B, Cd, Tl, Zn) in plant tissue which could be related to the plant's natural herbivory defense system or to land use. We conclude that land use influences the elemental composition of P. ceratophyllum, and potentially the quality and toxicity of the plant to herbivores and detritivores in eastern North American rivers.

Evaluating habitat use and relative abundance of Iowa's river otter with harvest data

AbstractThe North American river otter (Lontra canadensis) was extirpated from much of the United States in the early 20th century due to habitat loss, pollution of waterways, and overharvesting. The Iowa Department of Natural Resources began a river otter reintroduction effort in 1985, which placed otters in 14 sites across the state. Otters have since been known to occur in every county in Iowa and appear to have successfully repopulated their former range throughout the state. Our objective was to relate land cover characteristics and otter abundance using harvest data. We used data collected by agency staff to map the locations of otter harvest in Iowa from 2006 to 2016. We mapped otter harvest locations at the subwatershed level (also called 12‐digit Hydrologic Unit Code or HUC‐12). We related otter harvest to land cover variables and predicted otter abundance by land cover type. We found that roads, forests, larger waterways, and Ictaluridae (catfish) presence were negatively correlated with otter harvest. Variables positively correlated with otter harvest were areas with greater land cover diversity, wetland patch density, average stream density, and waterway and wetland areas. The land cover model predicted otters in equal or greater numbers than the harvest data in 62.8% of HUC‐12s. The areas of greatest otter abundance estimates were located near recreation areas and urban areas, indicating the underutilization of these heavy‐trafficked areas by trappers. Areas of fewer predicted otters were not concentrated in a single area of the state but occurred along the Interstate 80 corridor.

Multi‐method sampling increases detectability and assessment of spatio‐temporal interactions of mammals and birds in wetland habitats

Abstract Freshwater habitats support high levels of biodiversity and provide important habitat for wetland‐dependent taxa; however, impairment of aquatic connectivity through wetland loss, stream alterations and light pollution impacts species persistence and community resilience. Quantifying occupancy of these habitats to assess their use by mammals and birds can be challenging, especially for cryptic species. This study examines wetland habitat use by mammals and birds, and their spatial and temporal relationships within the Beaver Hills Biosphere in Alberta, Canada. As part of a multi‐method detection approach, camera boxes, cameras on beaver dams, and camera rafts allowed for multivariate analyses to determine temporal and spatial patterns of habitat use and species associations, while field sampling and environmental DNA (eDNA) provided data on site occupancy by a subset of semi‐aquatic mammals. From ~50,000 images, over 84 species were detected, including 52 species of birds and 25 species of mammals. Several species were spatially associated, and although most species of mammals exhibited temporal overlap, there were distinct differences, especially on beaver dams where predators such as coyotes and white‐tailed deer shared the same space. Temporally, birds were detected most often during the day and mammals at night. During new moon phases, use of beaver dams by beavers decreased dramatically, and use of camera rafts by muskrats increased. Winter field surveys allowed for a broad overview of wetland occupancy and abundance of some species, particularly by beavers and muskrats, and occasionally winter use by other semi‐aquatic mammals. Where there was limited detection of more cryptic species of semi‐aquatic mammals, eDNA analysis successfully detected American water shrew, American mink, North American river otter and northern bog lemming more often than camera and field methods. Applying a multi‐method monitoring approach for mammals and birds in wetland habitats is critical at a time when freshwater systems are experiencing dramatic declines in relative abundance of monitored wildlife populations, with many of these species underrepresented in conventional surveys.

Recovering predators link aquatic and terrestrial ecosystems: River otters subsidize coyotes with carrion.

Despite global declines in the abundance and distribution of predators, conservation and reintroduction efforts are increasingly leading to predator recoveries. Unexpected species interactions and ecological consequences often arise when these predator recoveries occur. Here, we describe a novel species interaction in which coyotes (Canis latrans) kleptoparasitize North American river otters (Lontra canadensis) in a region of river otter recovery along the north-central California coast, USA. We describe eight observations of coyotes scavenging otter-killed waterbird carrion, including one observation in which river otters aggressively defended their prey from a coyote kleptoparasite. These observations highlight the importance of carrion provisioning as an overlooked pathway through which river otters facilitate nutrient subsidies to terrestrial scavengers. This behavior may have ecological implications including effects on the abundance, behavior, and health of scavengers as well as their interspecific interactions. We propose hypotheses and questions regarding these ecological consequences to guide further investigations into the cross-ecosystem impacts of recovering river otter populations.

Improvement of Surimi Gel from Frozen-Stored Silver Carp.

Silver Carp (SC) is an under-utilized, invasive species in North American river systems. In this study, the synergistic effects of manufactured Microfiber (MMF), Transglutaminase (TG), and chicken skin collagen (CLG)) to enhance surimi gel quality from frozen SC were studied. The gel strength, textural properties, rheological properties, water-holding capacity (WHC), water mobility, microstructure, and protein composition of the gel samples were determined to assess the impact of the additives individually and synergistically. The results suggested that TG had the most pronounced effect on the surimi gel properties by promoting protein cross-linking. Synergistic effects between TG, MMF, and CLG can bring effective gel property enhancement larger than the individual effect of each additive alone. With the established response-surface models, the combination of CLG and MMF can be optimized to produce surimi gels with less TG but comparable in properties to that of the optimal result with high TG usage. The findings of this study provided a technical foundation for making high-quality surimi gel products out of frozen-stored SC with synergistic utilization of additives, which could serve as guidelines for the industrial development of new surimi products.

Rates of sedimentary organic carbon preservation in the Bering Sea and Chukchi Sea, and their response to climate change over the past 75 years

Rates of sedimentary organic carbon preservation in the Bering Sea and Chukchi Sea, and their response to climate change over the past 75 years