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USGS2021

Lake sturgeon seasonal movements in regulated and unregulated Missouri River tributaries

Spatio-temporal movement patterns of aquatic organisms drive many ecological processes. However, dams block migrations and alter the hydrologic and thermal regimes influencing movement behaviour of freshwater fishes. In North America, many recovering southern Lake Sturgeon populations occur in rivers with hydroelectric dams, but few studies have examined the impact of hydrologic alteration on their seasonal movements. We conducted a 3-year telemetry study of 96 adult and subadult Lake Sturgeon to compare their migratory responses to temperature and hydrology in adjacent regulated and unregulated tributaries of the Missouri River. Many other populations of Lake Sturgeon use tributaries primarily for spring spawning; however, in our study, Lake Sturgeon used Missouri River tributaries during 78% of the year. Differences in river size, hydrologic and thermal regimes in the regulated Osage River may have contributed to the greater year-round residency, later initiation, more frequent directional changes and longer duration of spring migrations compared to the unregulated Gasconade River. Lake Sturgeon made spring upstream migrations at temperatures of 13–19°C and elevated discharges in both rivers. However, Osage River migrants responded less to changes in discharge or temperature during spring migrations, especially those that overwintered at upstream locations. Fall tributary migrations occurred in the Osage River at rising or high discharges but were uncommon in the Gasconade River. Our identification of the influences of abiotic variables on the timing, duration and extent of Lake Sturgeon seasonal migrations can help guide management of habitat and hydrology in regulated rivers to recover migratory fishes globally.

Missouri↗

USGS2021

Exploration of the 2016 Yellowstone River fish kill and proliferative kidney disease in wild fish populations

Proliferative kidney disease (PKD) is an emerging disease that recently resulted in a large mortality event of salmonids in the Yellowstone River (Montana, USA). Total PKD fish mortalities in the Yellowstone River were estimated in the tens of thousands, which resulted in a multi‐week river closure and an estimated economic loss of US$500,000. This event shocked scientists, managers, and the public, as this was the first occurrence of the disease in the Yellowstone River, the only reported occurrence of the disease in Montana in the past 25 yr, and arguably the largest wild PKD fish kill in the world. To understand why the Yellowstone River fish kill occurred, we used molecular and historical data to evaluate evidence for several hypotheses: Was the causative parasite Tetracapsuloides bryosalmonae a novel invader, was the fish kill associated with a unique parasite strain, and/or was the outbreak caused by unprecedented environmental conditions? We found that T. bryosalmonae is widely distributed in Montana and have documented occurrence of this parasite in archived fish collected in the Yellowstone River prior to the fish kill. T. bryosalmonae had minimal phylogeographic population structure, as the DNA of parasites sampled from the Yellowstone River and distant water bodies were very similar. These results suggest that T. bryosalmonae could be endemic in Montana. Due to data limitations, we could not reject the hypothesis that the fish kill was caused by a novel and more virulent genetic strain of the parasite. Finally, we found that single‐year environmental conditions are insufficient to explain the cause of the 2016 Yellowstone River PKD outbreak. Other regional rivers where we documented T. bryosalmonae had similar or even more extreme conditions than the Yellowstone River and similar or more extreme conditions have occurred in the Yellowstone River in the recent past, yet mass PKD mortalities have not been documented in either instance. We conclude by placing these results and unresolved hypotheses into the broader context of international research on T. bryosalmonae and PKD, which strongly suggests that a better understanding of bryozoans, the primary host of T. bryosalmonae , is required for better ecosystem understanding.

Montana↗

USGS2023

High potential but low achievement: Frequent disturbance constrains the light use efficiency of river ecosystems

We rarely consider light limitation in ecosystem productivity, yet light limitation is a major constraint on river autotrophy. Because the light that reaches benthic autotrophs must first pass through terrestrial vegetation and an overlying water column that can be loaded with sediments or colored organic material, there is strong selection for river autotrophs to have high light use efficiencies (LUEs), that is, the efficiency at which light energy is converted to biomass. In contrast to prior studies that have estimated river LUE on single days, we calculated continuous LUE over more than 6 full years for 64 free-flowing rivers across the United States. This dataset represents the largest compilation of continuous estimates of daily rates of gross primary productivity (GPP) and daily light inputs from which we calculated daily estimates of LUE. Early estimates of LUE in rivers found that clearwater springs with stable flows could achieve LUEs of 4%, much higher than LUEs reported for terrestrial plants. We found that 53% of the rivers in our dataset have LUEs that exceed 4% on at least one day of their time series. Because of the high variability in daily LUE, measurements taken on any given day may misrepresent a river ecosystem's annual LUE. Though most rivers share a high potential, the mean annual LUE of all rivers in our dataset is much lower, only 0.5%. We found that rivers with more variable flow regimes had lower annual LUEs, which indicates that LUE is constrained by hydrologic disturbances that remove, bury, or shade autotrophic biomass. Comparisons of LUE across ecosystems allow us to reframe our view of rivers, by recognizing the high efficiency with which they convert light to biomass compared with lentic, marine, and terrestrial ecosystems.

conterminous United States↗

USGS2000

Biomarker response and health of polychlorinated biphenyl- and chlordane-contaminated paddlefish from the Ohio River Basin, USA

Fifty paddlefish ( Polyodon spathula ) collected from two sites on the Ohio River and from one site on the Cumberland River, USA, were examined to determine gonad polychlorinated biphenyl (PCB) and chlordane concentrations, amounts of plasma sex steroids (testosterone and estradiol), hepatic microsomal ethoxyresorufin- O -deethylase (EROD) activity, and the presence of immunoreactive cytochrome P450 1A (CYP1A) protein. Percent hatch and liver, spleen, and kidney histology were also determined. Gonad PCB and chlordane concentrations were significantly higher in Ohio River paddlefish than in Cumberland River paddlefish. Gonad PCB and chlordane concentration and gonad percent lipid were correlated in Ohio River paddlefish. Five of 10 Ohio River egg samples exceeded the Food and Drug Administration's action limit for chlordane (0.30 μg/g). Polychlorinated biphenyl congener-specific analysis detected predominantly the tetra-, penta-, and hexachlorobiphenyls in paddlefish testes. Plasma testosterone levels were significantly lower in males collected from the upper Ohio River site than those collected from the lower part of the river. There was no measurable hepatic microsomal EROD activity in any of the 50 paddlefish collected from the three sites. Western blotting analysis confirmed that a rabbit antitrout CYP1A1 IgG antibody did not recognize a CYP1A protein in paddlefish liver microsomes. Percent hatch was not significantly different in eggs collected from the Cumberland (88–96%) and Ohio Rivers (90–95%). Histological analysis of liver, spleen, and kidney detected the presence of hepatic steatosis and hemosiderosis, splenic lymphoid cell depletion, and hyperplasia of interrenal and chromaffin tissues. Immunosuppression, hepatic metabolic disorders, and altered neuroendocrine function may be occurring in Ohio River paddlefish. Results presented here suggest that organochlorine exposure may be jeopardizing the long-term health of Ohio River paddlefish and that additional investigation of contaminant effects on immune system function and hormone levels in paddlefish is warranted.

Alabama, Georgia, Illinois, Indiana, Kentucky, Mar↗

USGS2015

Rethinking the longitudinal stream temperature paradigm: region-wide comparison of thermal infrared imagery reveals unexpected complexity of river temperatures

Prevailing theory suggests that stream temperature warms asymptotically in a downstream direction, beginning at the temperature of the source in the headwaters and leveling off downstream as it converges to match meteorological conditions. However, there have been few empirical examples of longitudinal patterns of temperature in large rivers due to a paucity of data. We constructed longitudinal thermal profiles (temperature versus distance) for 53 rivers in the Pacific Northwest (USA) using an extensive dataset of remotely sensed summertime river temperatures and classified each profile into one of five patterns of downstream warming: asymptotic (increasing then flattening), linear (increasing steadily), uniform (not changing), parabolic (increasing then decreasing), or complex (not fitting other classes). We evaluated (1) how frequently profiles warmed asymptotically downstream as expected, and (2) whether relationships between river temperature and common hydroclimatic variables differed by profile class. We found considerable diversity in profile shape, with 47% of rivers warming asymptotically, and 53% having alternative profile shapes. Water temperature did not warm substantially over the course of the river for coastal parabolic and uniform profiles, and for some linear and complex profiles. Profile classes showed no clear geographical trends. The degree of correlation between river temperature and hydroclimatic variables differed among profile classes, but there was overlap among classes. Water temperature in rivers with asymptotic or parabolic profiles was positively correlated with August air temperature, tributary temperature and velocity, and negatively correlated with elevation, August precipitation, gradient, and distance upstream. Conversely, associations were less apparent in rivers with linear, uniform, or complex profiles. Factors contributing to the unique shape of parabolic profiles differed for coastal and inland rivers, where downstream cooling was influenced locally by climate or cool water inputs, respectively. Potential drivers of shape for complex profiles were specific to each river. These thermal patterns indicate diverse thermal habitats that may promote resilience of aquatic biota to climate change. Without this spatial context, climate change models may incorrectly estimate loss of thermally suitable habitat.

California, Idaho, Oregon, Washington↗

USGS2001

The effect of mining and related activities on the sediment-trace element geochemistry of Lake Coeur d'Alene, Idaho, USA. Part III. Downstream effects: The Spokane River Basin

During 1998/1999, surface and subsurface sediment samples were collected along the entire length of the Spokane River from its outlet at the northern end of Lake Coeur d'Alene (CDA), Idaho, to Lake Roosevelt on the Columbia River, Washington. The study was conducted to determine if the trace element enrichments observed in Lake CDA and on the floodplain and in the CDA River extend through the Spokane River Basin (SRB). As in Lake CDA, surface sediments in the SRB are enriched in Pb, Zn, As, Cd, Sb and Hg relative to local background levels. Pb, Cd and Zn are the most elevated, with maximum enrichment occurring in the upper Spokane River in close proximity to Lake CDA. On average, enrichment decreases downstream, apparently reflecting both increased distance from the inferred source (the CDA River Basin), as well as increased dilution by locally derived but unenriched materials. Only Cd and Zn display marked enrichment throughout the SRB. Pb, Zn and Cd seem to be associated mainly with an operationally defined iron oxide phase, whereas the majority of the As and Sb seem to be matrix-held. Subsurface sediments also are enriched in Pb, Zn, As, Cd, Sb and Hg relative to background levels. Based on 137Cs and excess 210Pb dating, trace element enrichment began in the middle part of the SRB (Long Lake) between 1900 and 1920. This is contemporaneous with similar enrichments observed in Lake CDA, as well as the completion of Long Lake Dam (1913). In the most downstream part of the basin (Spokane River Arm of Lake Roosevelt), enrichment began substantially later, between 1930 and 1940. The temporal difference in enrichment between Long Lake and the River Arm may reflect the latter's greater distance from the presumed source of the enrichment (the CDA River Basin); however, the difference is more likely the result of the completion of Grand Coulee Dam (1934-1941), which formed Lake Roosevelt, backed up the Spokane River, and increased water levels in the River Armby about 30 m.

Hydrological Processes↗

USGS2011

In situ quantification of spatial and temporal variability of hyporheic exchange in static and mobile gravel-bed rivers

Seepage meters modified for use in flowing water were used to directly measure rates of exchange between surface and subsurface water in a gravel‐ and cobble bed river in western Pennsylvania, USA (Allegheny River, Qmean = 190 m3/s) and a sand‐ and gravel‐bed river in Colorado, USA (South Platte River, Qmean = 9·7 m3/s). Study reaches at the Allegheny River were located downstream from a dam. The bed was stable with moss, algae, and river grass present in many locations. Median seepage was + 0·28 m/d and seepage was highly variable among measurement locations. Upward and downward seepage greatly exceeded the median seepage rate, ranging from + 2·26 (upward) to − 3·76 (downward) m/d. At the South Platte River site, substantial local‐scale bed topography as well as mobile bedforms resulted in spatial and temporal variability in seepage greatly in exceedence of the median groundwater discharge rate of 0·24 m/d. Both upward and downward seepage were recorded along every transect across the river with rates ranging from + 2·37 to − 3·40 m/d. Despite a stable bed, which commonly facilitates clogging by fine‐grained or organic sediments, seepage rates at the Allegheny River were not reduced relative to those at the South Platte River. Seepage rate and direction depended primarily on measurement position relative to local‐ and meso‐scale bed topography at both rivers. Hydraulic gradients were small at nearly all seepage‐measurement locations and commonly were not a good indicator of seepage rate or direction. Therefore, measuring hydraulic gradient and hydraulic conductivity at in‐stream piezometers may be misleading if used to determine seepage flux across the sediment‐water interface. Such a method assumes that flow between the well screen and sediment‐water interface is vertical, which appears to be a poor assumption in coarse‐grained hyporheic settings.

Pennsylvania↗

USGS2020

Movement dynamics of nonnative Burbot in the upper Green River system and implications for management

Burbot Lota lota were illegally introduced to the Green River, Wyoming, in the mid-1990s and pose a threat to recreational fisheries and native fish conservation. Although much is known about Burbot population dynamics, little is known about their movement patterns. Our objectives were to describe the movement dynamics of Burbot in the upper Green River system to provide information on the ecology of Burbot and insight on possible management actions. In total, 875 Burbot were tagged with PIT tags in the upper Green River and Fontenelle Reservoir; their movements were tracked from August 2016 to March 2018. Additionally, 22 Burbot were tagged with radio transmitters in Fontenelle Reservoir in November 2017, and 13 Burbot were tagged with radio transmitters in the upper Green River in November 2018. Of these fish, 11 Burbot tagged in Fontenelle Reservoir and all river-tagged Burbot were tracked as they migrated into the Green River and associated tributaries during the spawning season. Upstream and downstream movements of Burbot tagged with PIT tags in Fontenelle Reservoir and the upper Green River peaked during December–January and were synchronized with river temperatures reaching 0°C. Of the total number of PIT-tagged Burbot, 10–15% of those tagged in Fontenelle Reservoir were detected in the Green River during the spawning season and 15% of those tagged in the Green River were detected moving downstream toward Fontenelle Reservoir during the spawning period. Movements of radiotelemetered Burbot were synchronized with river ice-up in mid-December. Maximum upstream distance traveled by adfluvial Burbot was 5.8 km. Fluvial Burbot primarily migrated downstream during the spawning period, and maximum downstream distance traveled was 17.7 km. Detection data suggest that both fluvial and adfluvial Burbot occupy the same reaches during the spawning period and areas near Fontenelle Reservoir are important for spawning. Results of this study will assist with the management of Burbot in this system by shedding light on Burbot movement patterns and identifying areas of high Burbot use for targeted suppression efforts. Results also contribute to our understanding of the variability in Burbot ecology.

Wyoming↗

USGS1991

Limnological aspects of the St. Clair River

To better characterize neoplasm epizootics in the Great Lakes basin and their association with families of contaminants, we sampled five locations: the Fox and Menominee rivers, Lake Michigan; Munuscong Lake, St. Mary's River; and the Black and Cuyahoga rivers, Lake Erie. Frequencies of external and liver tumors were determined for brown bullhead ( Ictalurus nebulosus ) from all locations except the Black River and for walleye ( Stizostedion vitreum ) from the Lake Michigan and St. Mary's River sites. Sediment samples were analyzed for metals, polychlorinated aromatics, and polynuclear aromatic hydrocarbons (PAH). Liver neoplasms occurred in brown bullhead from the Cuyahoga River and Munuscong Lake; brown bullhead captured from Munuscong Lake were older than those collected from the other locations. Brown bullhead from these same two rivers had elevated hepatosomatic indexes. No liver neoplasms were found in brown bullhead from the Fox and Menominee rivers, although polychlorinated aromatics were highest in both Fox River sediment and Fox and Menominee brown bullhead, and arsenic was highest in Menominee River sediment and fish. Liver neoplasms in brown bullhead from the Cuyahoga River fit the prevailing hypothesis that elevated PAH in sediment can induce cancer in wild fish. The cause of the liver neoplasms in Munuscong Lake brown bullhead is undetermined.

Michigan;Ontario↗

USGS2000

Field evaluation of lead effects on Canada geese and mallards in the Coeur d'Alene River Basin, Idaho

Hatch year (HY) mallards ( Anas platyrhynchos ) in the Coeur d'Alene (CDA) River Basin had higher concentrations of lead in their blood than HY Western Canada geese ( Branta canadensis moffitti ) (geometric means 0.98 versus 0.28 μg/g, wet weight). The pattern for adults of both species was similar, although geometric means (1.77 versus 0.41 μg/g) were higher than in HY birds. HY mallards captured in the CDA River Basin in 1987 contained significantly lower lead concentrations in their blood than in 1994–95 (0.36 versus 0.98 μg/g); however, some very young mallards were sampled in 1987, and concentrations in adults were not significantly different in 1987, 1994, or 1995 (1.52, 2.07, 1.55 μg/g, respectively). Both species in the CDA River Basin in 1994–95 showed significantly reduced red blood cell delta-aminolevulinic acid dehydratase (ALAD) activity compared to the reference areas: Canada geese (HY −65.4 to −86.0%, adults −82.3%), and mallards (HY −90.7 to −95.5%, adults −94.1%). Canada goose goslings were divided into size classes, and the two smaller classes from the CDA River Basin had significantly elevated free erythrocyte protoporphyrin (protoporphyrin) levels compared to the reference area (15.2× and 6.9×). HY and adult mallards both had significantly elevated protoporphyrin (5.9× and 7.5×). Recognizing that interspecific differences exist in response and sensitivity to lead, it appears (at least for hemoglobin and hematocrit) that Canada geese were more sensitive to lead than mallards, i.e ., adverse hematologic effects occur at lower blood lead concentrations. Only Canada geese from the CDA River Basin, in spite of lower blood lead concentrations, had significantly reduced mean hemoglobin and hematocrit values. No euthanized Canada geese (all HYs) from CDA River Basin were classified as clinically lead poisoned, but 38 Canada geese found dead in the CDA River Basin during a concurrent study succumbed to lead poisoning between 1992 and 1997. Only 6 (15.8%) of these 38 contained ingested lead shot, which contrasts greatly with the 75–94% incidence of ingested lead shot when mortality was due to lead shot ingestion. Lead from other contaminated sources ( i.e ., sediments and vegetation) in the CDA River Basin was strongly implicated in most Canada goose deaths. Based on the 31 live mallards and Canada geese collected in the CDA River Basin, which were representative of the live populations blood sampled only, the prevalence of subclinical and clinical lead poisoning (as determined by liver lead concentrations, excluding birds with ingested lead shot) was higher in mallards: subclinical (4 of 8, 50% HYs and 6 of 11, 55% adults); clinical (0% HYs and 4 of 11, 36% adults), with less data available for Canada geese (only 1 of 9, 11% HYs marginally subclinical). The clinically lead-poisoned mallards had extremely high concentrations of lead in blood (2.69–8.82 μg/g) and liver (6.39–17.89 μg/g). Eight mallards found dead in the CDA River Basin during a concurrent study were diagnosed as lead poisoned, and only one (12.5%) contained ingested lead shot, which again strongly implicates other lead sources. The finding of dead lead poisoned Canada geese together with the high percentage of live mallards classified as subclinically or clinically lead poisoned, in combination with the low incidence of ingested lead shot causes us concern for both of these species, which live in association with lead-contaminated sediment in the CDA River Basin.

Idaho↗

USGS2000

Effects of contaminants in dredge material from the Lower Savannah River

Contaminants entering aquatic systems from agricultural, industrial, and municipal activities are generally sequestered in bottom sediments. The environmental significance of contaminants associated with sediments dredged from Savannah Harbor, Georgia, USA, are unknown. To evaluate potential effects of contaminants in river sediments and sediments dredged and stored in upland disposal areas on fish and wildlife species, solid-phase sediment and sediment pore water from Front River, Back River, an unnamed Tidal Creek on Back River, and Middle River of the distributary system of the lower Savannah River were tested for toxicity using the freshwater amphipod Hyalella azteca . In addition, bioaccumulation of metals from sediments collected from two dredge-disposal areas was determined using the freshwater oligochaete Lumbriculus variegatus . Livers from green-winged teals ( Anas crecca ) and lesser yellowlegs ( Tringa flavipes ) foraging in the dredge-spoil areas and raccoons ( Procyon lotor ) from the dredge-disposal/river area and an upland site were collected for metal analyses. Survival of H. azteca was not reduced in solid-phase sediment exposures, but was reduced in pore water from several locations receiving drainage from dredge-disposal areas. Basic water chemistry (ammonia, alkalinity, salinity) was responsible for the reduced survival at several sites, but PAHs, metals, and other unidentified factors were responsible at other sites. Metal residues in sediments from the Tidal Creek and Middle River reflected drainage or seepage from adjacent dredge-disposal areas, which could potentially reduce habitat quality in these areas. Trace metals increased in L. variegatus exposed in the laboratory to dredge-disposal sediments; As, Cu, Hg, Se, and Zn bioaccumulated to concentrations higher than those in the sediments. Certain metals (Cd, Hg, Mo, Se) were higher in livers of birds and raccoons than those in dredge-spoil sediments suggesting bioavailability. Cadmium, Ct, Hg, Pb, and Se in livers from raccoons collected near the river and dredge-disposal areas were significantly higher than those of raccoons from the upland control site. Evidence of bioaccumulation from laboratory and field evaluations and concentrations in sediments from dredge-disposal areas and river channels demonstrated that some metals in the dredge-disposal areas are mobile and biologically available. Drainage from dredge-disposal areas may be impacting habitat quality in the river, and fish and wildlife that feed and nest in the disposal area pm the lower Savannah River may be at risk from metal contamination.

Georgia, South Carolina↗

USGS2005

Assessing ecological integrity of Ozark rivers to determine suitability for protective status

Preservation of extraordinary natural resources, protection of water quality, and restoration of impaired waters require a strategy to identify and protect least-disturbed streams and rivers. We applied two objective, quantitative methods to determine stream ecological integrity of headwater reaches of 10 Ozark rivers, 5 with Wild and Scenic River federal protective status. Thirty-four variables representing macroinvertebrate and fish assemblage characteristics, in-stream habitat, riparian vegetation, water quality, and watershed attributes were quantified for each river and analyzed using two multivariate approaches. The first approach, cluster and discriminant analyses, identified two groups of river with only one variable (% forested watershed) reliably distinguishing groups. Our second approach employed ordinal scaling to compare variables for each river to conceptually ideal conditions that were developed as a composite of optimal attributes among the 10 rivers. The composite distance of each river from ideal was then calculated using a unidimensional ranking technique. Two rivers without Wild and Scenic River designation ranked highest relative to ideal (highest ecological integrity), and two others, also without designation, ranked most distant from ideal (lowest ecological integrity). Fish density, number of intolerant fish species, and invertebrate density were influential biotic variables for scaling. Contributing physical variables included riparian forest cover, water nitrate concentration, water turbidity, percentage of forested watershed, percentage of private land ownership, and road density. These methods provide a framework for refinement and application in other regions to facilitate the process of establishing least-disturbed reference conditions and identifying rivers for protection and restoration. ?? 2005 Springer Science+Business Media, Inc.

Environmental Management↗

USGS2012

Uranium isotopes (234U/238U) in rivers of the Yukon Basin (Alaska and Canada) as an aid in identifying water sources, with implications for monitoring hydrologic change in arctic regions

The ability to detect hydrologic variation in large arctic river systems is of major importance in understanding and predicting effects of climate change in high-latitude environments. Monitoring uranium isotopes ( 234 U and 238 U) in river water of the Yukon River Basin of Alaska and northwestern Canada (2001–2005) has enhanced the ability to identify water sources to rivers, as well as detect flow changes that have occurred over the 5-year study. Uranium isotopic data for the Yukon River and major tributaries (the Porcupine and Tanana rivers) identify several sources that contribute to river flow, including: deep groundwater, seasonally frozen river-valley alluvium groundwater, and high-elevation glacial melt water. The main-stem Yukon River exhibits patterns of uranium isotopic variation at several locations that reflect input from ice melt and shallow groundwater in the spring, as well as a multi-year pattern of increased variability in timing and relative amount of water supplied from higher elevations within the basin. Results of this study demonstrate both the utility of uranium isotopes in revealing sources of water in large river systems and of incorporating uranium isotope analysis in long-term monitoring of arctic river systems that attempt to assess the effects of climate change.

Yukon Basin↗

USGS2019

Sources, fate, and flux of geothermal solutes in the Yellowstone and Gardner Rivers, Yellowstone National Park, WY

The total discharge and thermal output from the numerous hydrothermal features in Yellowstone National Park (YNP) can be estimated from the chloride (Cl) flux in the Madison, Yellowstone, Falls, and Snake Rivers. Monitoring the Cl flux in these four major rivers provides a holistic view of the hydrothermal output from YNP and changes in the Cl flux may indicate changes in geothermal or magmatic activity. In this study, the source, fate, and flux of geothermal solutes in the Yellowstone River and Gardner Rivers were determined. Beginning in 2012, the fluxes of geothermal solutes, including Cl, were determined at monitoring sites in the Yellowstone and Gardner Rivers downstream of geothermal inputs within YNP. A method was developed using specific conductance as a surrogate measure for solute concentrations at these monitoring sites. Combining continuous (15-min) specific conductance and discharge data, Cl and other geothermal solute fluxes were determined at both sites and approximately 32% of the Cl flux exiting YNP is from the Yellowstone River watershed. Synoptic sampling of river water and discharge measurements were performed during low-flow conditions of September 2014 allowed for the determinations of geothermal solute sources and their downstream fate. Thus, the contribution of geothermal solutes from the various geothermal areas at the downstream monitoring sites was quantified. The thermal features draining into Yellowstone Lake account for 34% of the Cl flux at the Yellowstone River monitoring site which is located approximately 5 km north of YNP. The Gardner River, which captures geothermal water from Mammoth Hot Springs, is responsible for 22% of the Cl at the Yellowstone River monitoring site. Because the Yellowstone River watershed is large and contains numerous thermal areas, knowing the source and fate of geothermal solutes is import baseline information that can be used to identify future changes in thermal activity.

Wyoming↗

USGS2013

Late Quaternary stream piracy and strath terrace formation along the Belle Fourche and lower Cheyenne Rivers, South Dakota and Wyoming

Stream piracy substantially affected the geomorphic evolution of the Missouri River watershed and drainages within, including the Little Missouri, Cheyenne, Belle Fourche, Bad, and White Rivers. The ancestral Cheyenne River eroded headward in an annular pattern around the eastern and southern Black Hills and pirated the headwaters of the ancestral Bad and White Rivers after ~ 660 ka. The headwaters of the ancestral Little Missouri River were pirated by the ancestral Belle Fourche River, a tributary to the Cheyenne River that currently drains much of the northern Black Hills. Optically stimulated luminescence (OSL) dating techniques were used to estimate the timing of this piracy event at ~ 22–21 ka. The geomorphic evolution of the Cheyenne and Belle Fourche Rivers is also expressed by regionally recognized strath terraces that include (from oldest to youngest) the Sturgis, Bear Butte, and Farmingdale terraces. Radiocarbon and OSL dates from fluvial deposits on these terraces indicate incision to the level of the Bear Butte terrace by ~ 63 ka, incision to the level of the Farmingdale terrace at ~ 40 ka, and incision to the level of the modern channel after ~ 12–9 ka. Similar dates of terrace incision have been reported for the Laramie and Wind River Ranges. Hypothesized causes of incision are the onset of colder climate during the middle Wisconsinan and the transition to the full-glacial climate of the late-Wisconsinan/Pinedale glaciation. Incision during the Holocene of the lower Cheyenne River is as much as ~ 80 m and is 3 to 4 times the magnitude of incision at ~ 63 ka and ~ 40 ka. The magnitude of incision during the Holocene might be due to a combined effect of three geomorphic processes acting in concert: glacial isostatic rebound in lower reaches (~ 40 m), a change from glacial to interglacial climate, and adjustments to increased watershed area resulting from piracy of the ancestral headwaters of the Little Missouri River.

Montana, Nebraska, North Dakota, South Dakota, Wyo↗

USGS2015

Large-scale dam removal on the Elwha River, Washington, USA: coastal geomorphic change

Two dams on the Elwha River, Washington State, USA trapped over 20 million m 3 of mud, sand, and gravel since 1927, reducing downstream sediment fluxes and contributing to erosion of the river's coastal delta. The removal of the Elwha and Glines Canyon dams, initiated in September 2011, induced massive increases in river sediment supply and provided an unprecedented opportunity to examine the geomorphic response of a coastal delta to these increases. Detailed measurements of beach topography and nearshore bathymetry show that ~ 2.5 million m 3 of sediment was deposited during the first two years of dam removal, which is ~ 100 times greater than deposition rates measured prior to dam removal. The majority of the deposit was located in the intertidal and shallow subtidal region immediately offshore of the river mouth and was composed of sand and gravel. Additional areas of deposition include a secondary sandy deposit to the east of the river mouth and a muddy deposit west of the mouth. A comparison with fluvial sediment fluxes suggests that ~ 70% of the sand and gravel and ~ 6% of the mud supplied by the river was found in the survey area (within about 2 km of the mouth). A hydrodynamic and sediment transport model, validated with in-situ measurements, shows that tidal currents interacting with the larger relict submarine delta help disperse fine sediment large distances east and west of the river mouth. The model also suggests that waves and currents erode the primary deposit located near the river mouth and transport sandy sediment eastward to form the secondary deposit. Though most of the substrate of the larger relict submarine delta was unchanged during the first two years of dam removal, portions of the seafloor close to the river mouth became finer, modifying habitats for biological communities. These results show that river restoration, like natural changes in river sediment supply, can result in rapid and substantial coastal geomorphological responses.

Washington↗

USGS2002

Sources of terrestrially-derived organic carbon in lower Mississippi River and Louisiana shelf sediments: Implications for differential sedimentation and transport at the coastal margin

In this study, we examined the temporal and spatial variability of terrestrial organic carbon sources in lower Mississippi River and Louisiana shelf sediments (during 11 cruises over a 22-month period) to further understand the sorting dynamics and selective transport of vascular plant materials within the primary dispersal system of the river. Bulk ??13C values in lower river sediments ranged from -21.90??? to -24.64??? (mean=-23.20??1.09???), these values were generally more depleted than those found in shelf sediments (-22.5??? to -21.2???). The ??8 (??8 = sum of vanillyl, syringyl and cinnamyl phenols produced from the oxidation of 100 mg of organic carbon) values in the lower river ranged from 0.71 to 3.74 (mean = 1.78??0.23). While there was no significant relationship between ??8 and river discharge (p>0.05), the highest value occurred during peak discharge in April 1999-which corresponded to the highest observed C/N value of 17.41. The ??8 values on the shelf ranged from 0.68 to 1.36 (mean = 0.54??0.30) and were significantly lower (p <0.05) than the average value for lower river sediments. The range of S/V (syringyl/vanillyl) and C/V (cinnamyl/vanillyl) ratios on the shelf, 0.11 to 0.95 and 0.01 to 0.08, respectively, were similar to that found in the lower river. These low C/V ratios are indicative a mixture of woody and non-woody carbon sources. Recent work by Goni et al. [Nature 389 (1997) 275; Geochim. Cosmochim. Acta 62 (1998) 3055], which did not include sampling transects within the primary dispersal system of the Mississippi River, showed a non-woody vascular plant signature on the Louisiana shelf. This suggests that riverine-derived woody tissues preferentially settle out of the water column, in the lower river and inner shelf, prior to the selective dispersal of C3 versus C4 non-woody materials in other regions the shelf and slope. This works further demonstrates the importance of differential settlement of particles, sampling location within the dispersal system, and river discharge, when examining biogeochemical cycles in river-dominated margins. ?? 2002 Elsevier Science B.V. All rights reserved.

Marine Chemistry↗

USGS1998

Determination of bioavailable contaminants in the lower Missouri River following the flood of 1993

The semipermeable membrane device (SPMD) technology was employed to determine the presence of bioavailable organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polyaromatic hydrocarbons (PAHs)in the water of the main stem of the lower Missouri River and three of its tributaries. The SPMDs were deployed in 1994 following the extensive flood of 1993. Specifically, the SPMDs were deployed for 28 days at Wilson State Park, IA; Nebraska City, NE; Parkville, MO; the Kansas River in Kansas City, KS; Napoleon, MO; the Grand River; Glasgow, MO; the Missouri River upstream from the confluence of the Gasconade River; the Gasconade River, and Hermann, MO. Contaminant residues were found at all sites and at higher concentrations than found in the earlier pre-flood sampling. For example, in the present study, dieldrin was found to range from a low of 110 ng/sample in the Gasconade River to a high of 2000 ng/sample at Glasgow, while in the pre- flood sampling, dieldrin ranged from a low of 64 ng/sample at Sioux City to a high of 800 ng/sample at Glasgow. In contrast to the 1992 sampling, residues of PCBs were found at all 1994 sampling sites except the Gasconade River. Samples from Wilson State Park and the Grand River had 3100 and 2700 ng of PCBs/sample, respectively. These two concentrations are about an order of magnitude higher than the older sites and are likely indicative of point source inputs. PAHs were present in SPMD samples from three sites near Kansas City. The contaminant residues sequestered by the SPMDs represent an estimation of the bioavailable (via respiration) contaminants present in the main stem of the lower Missouri River and three of its major tributaries following an extensive flood event.The semipermeable membrane device (SPMD) technology was employed to determine the presence of bioavailable organochlorine pesticides, polychlorinated biphenyls, and polyaromatic hydrocarbons in the water of the main stem of the lower Missouri River and three of its tributaries. The SPMD were deployed in 1994 following an extensive flood in 1993. Contaminants residues were found at all sites and at higher concentrations than found in the earlier pre-flood sampling.

Environmental Science & Technology↗