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USGS2011

Water-quality conditions near the confluence of the Snake and Boise Rivers, Canyon County, Idaho

Total Maximum Daily Loads (TMDLs) have been established under authority of the Federal Clean Water Act for the Snake River-Hells Canyon reach, on the border of Idaho and Oregon, to improve water quality and preserve beneficial uses such as public consumption, recreation, and aquatic habitat. The TMDL sets targets for seasonal average and annual maximum concentrations of chlorophyll- a at 14 and 30 micrograms per liter, respectively. To attain these conditions, the maximum total phosphorus concentration at the mouth of the Boise River in Idaho, a tributary to the Snake River, has been set at 0.07 milligrams per liter. However, interactions among chlorophyll- a , nutrients, and other key water-quality parameters that may affect beneficial uses in the Snake and Boise Rivers are unknown. In addition, contributions of nutrients and chlorophyll- a loads from the Boise River to the Snake River have not been fully characterized. To evaluate seasonal trends and relations among nutrients and other water-quality parameters in the Boise and Snake Rivers, a comprehensive monitoring program was conducted near their confluence in water years (WY) 2009 and 2010. The study also provided information on the relative contribution of nutrient and sediment loads from the Boise River to the Snake River, which has an effect on water-quality conditions in downstream reservoirs. State and site-specific water-quality standards, in addition to those that relate to the Snake River-Hells Canyon TMDL, have been established to protect beneficial uses in both rivers. Measured water-quality conditions in WY2009 and WY2010 exceeded these targets at one or more sites for the following constituents: water temperature, total phosphorus concentrations, total phosphorus loads, dissolved oxygen concentration, pH, and chlorophyll- a concentrations (WY2009 only). All measured total phosphorus concentrations in the Boise River near Parma exceeded the seasonal target of 0.07 milligram per liter. Data collected during the study show seasonal differences in all measured parameters. In particular, surprisingly high concentrations of chlorophyll- a were measured at all three main study sites in winter and early spring, likely due to changes in algal populations. Discharge conditions and dissolved orthophosphorus concentrations are key drivers for chlorophyll- a on a seasonal and annual basis on the Snake River. Discharge conditions and upstream periphyton growth are most likely the key drivers for chlorophyll- a in the Boise River. Phytoplankton growth is not limited or driven by nutrient availability in the Boise River. Lower discharges and minimal substrate disturbance in WY2010 in comparison with WY2009 may have caused prolonged and increased periphyton and macrophyte growth and a reduced amount of sloughed algae in suspension in the summer of WY2010. Chlorophyll- a measured in samples commonly is used as an indicator of sestonic algae biomass, but chlorophyll- a concentrations and fluorescence may not be the most appropriate surrogates for algae growth, eutrophication, and associated effects on beneficial uses. Assessment of the effects of algae growth on beneficial uses should evaluate not only sestonic algae, but also benthic algae and macrophytes. Alternatively, continuous monitoring of dissolved oxygen detects the influence of aquatic plant respiration for all types of algae and macrophytes and is likely a more direct measure of effects on beneficial uses such as aquatic habitat. Most measured water-quality parameters in the Snake River were statistically different upstream and downstream of the confluence with the Boise River. Higher concentrations and loads were measured at the downstream site (Snake River at Nyssa) than the upstream site (Snake River near Adrian) for total phosphorus, dissolved orthophosphorus, total nitrogen, dissolved nitrite and nitrate, suspended sediment, and turbidity. Higher dissolved oxygen concentrations and pH were measured at the upstream site (Snake River near Adrian) than the downstream site (Snake River at Nyssa). Contributions from the Boise River measured at Parma do not constitute all of the increase in nutrient and sediment loads in the Snake River between the upstream and downstream sites. Surrogate models were developed using a combination of continuously monitored variables to estimate concentrations of nutrients and suspended sediment when samples were not possible. The surrogate models explained from 66 to 95 percent of the variability in nutrient and suspended sediment concentrations, depending on the site and model. Although the surrogate models could not always represent event-based changes in modeled parameters, they generally were successful in representing seasonal and annual patterns. Over a longer period, the surrogate models could be a useful tool for measuring compliance with state and site-specific water-quality standards and TMDL targets, for representing daily and seasonal variability in constituents, and for assessing effects of phosphorus reduction measures within the watershed.

Idaho↗

USGS2018

Simulation of hydrodynamics, water quality, and lake sturgeon habitat volumes in Lake St. Croix, Wisconsin and Minnesota, 2013

Lake St. Croix is a naturally impounded, riverine lake that makes up the last 40 kilometers of the St. Croix River. Substantial land-use changes during the past 150 years, including increased agriculture and urban development, have reduced Lake St. Croix water-quality and increased nutrient loads delivered to Lake St. Croix. A recent (2012–13) total maximum daily load phosphorus-reduction plan set the goal to reduce total phosphorus loads to Lake St. Croix by 20 percent by 2020 and reduce Lake St. Croix algal bloom frequencies. The U.S. Geological Survey, in cooperation with the National Park Service, developed a two-dimensional, carbon-based, laterally averaged, hydrodynamic and water-quality model, CE–QUAL–W2, that addresses the interaction between nutrient cycling, primary production, and trophic dynamics to predict responses in the distribution of water temperature, oxygen, and chlorophyll a. Distribution is evaluated in the context of habitat for lake sturgeon, including a combination of temperature and dissolved oxygen conditions termed oxy-thermal habitat. The Lake St. Croix CE–QUAL–W2 model successfully reproduced temperature and dissolved oxygen in the lake longitudinally (from upstream to downstream), vertically, and temporally over the seasons. The simulated water temperature profiles closely matched the measured water temperature profiles throughout the year, including the prediction of thermocline transition depths (often within 1 meter), the absolute temperature of the thermocline transitions (often within 1.0 degree Celsius), and profiles without a strong thermocline transition. Simulated dissolved oxygen profiles matched the trajectories of the measured dissolved oxygen concentrations at multiple depths over time, and the simulated concentrations matched the depth and slope of the measured concentrations. Additionally, trends in the measured water-quality data were captured by the model simulation, gaining some potential insights into the underlying mechanisms of critical Lake St. Croix metabolic processes. The CE–QUAL–W2 model tracked nitrate plus nitrite, total nitrogen, and total phosphorus throughout the year. Inflow nutrient contributions (loads), largely dominated by upstream St. Croix River loads, were the most important controls on Lake St. Croix water quality. Close to 60 percent of total phosphorus to the lake was from phosphorus derived from organic matter, and about 89 percent of phosphorus to Lake St. Croix was delivered by St. Croix River inflows. The Lake St. Croix CE–QUAL–W2 model offered potential mechanisms for the effect of external and internal loadings on the biotic response regarding the modeled algal community types of diatoms, green algae, and blue-green algae. The model also suggested the seasonal dominance of blue-green algae in all four pools of the lake. A sensitivity analysis was completed to test the total maximum daily load phosphorus-reduction scenario responses of total phosphorus and chlorophyll a. The modeling indicates that phosphorus reductions would result in similar Lake St. Croix reduced concentrations, although chlorophyll a concentrations did not decrease in the same proportional amounts as the total phosphorus concentrations had decreased. The smaller than expected reduction in algal growth rates highlighted that although inflow phosphorus loads are important, other constituents also can affect the algal response of the lake, such as changes in light penetration and the breakdown of organic matter releasing nutrients. The available habitat suitable for lake sturgeon was evaluated using the modeling results to determine the total volume of good-growth habitat, optimal growth habitat, and lethal temperature habitat. Overall, with the calibrated model, the fish habitat volume in general contained a large proportion of good-growth habitat and a sustained period of optimal growth habitat in the summer. Only brief periods of lethal oxy-thermal habitat were present in Lake St. Croix during the model simulation.

Minnesota, Wisconsin↗

USGS2024

A predictive analysis of water use for Providence, Rhode Island

To explain the drivers of historical water use in the public water systems (PWSs) that serve populations in Providence, Rhode Island, and surrounding areas, and to forecast future water use, a machine-learning model (cubist regression) was developed by the U.S. Geological Survey in cooperation with Providence Water to model daily per capita rates of domestic, commercial, and industrial water use. The PWSs in this area form a connected network that sources water from the Scituate Reservoir in Rhode Island. The cubist regression model was trained and tested on daily per capita rates for three categories of water use (domestic, commercial, and industrial) that were developed from quarterly water sales data and U.S. Census Bureau population estimates within each PWS service area from January 2005 through December 2021. The model was then used to make forecasts of future water use under varying scenarios of climate change, population growth, and economic growth for the years 2030 and 2040. The resulting daily per capita rates, which were modeled from the historical data, had an r 2 value of 0.94 and root mean square error of 6.7 gallons per capita daily. Results of the model were used to estimate total water use (the product of daily per capita rates and population) for all public water systems over the historical study period. Daily per capita rates in the study area decreased from 2005 to 2021, while population increased during that same period. “Category of water use” was the variable with the greatest explanatory power for modeling daily per capita rates. Overall, both daily per capita rates and total water use were projected to decrease in 2030 and 2040, in comparison to historical values from 2005 to 2021. Daily per capita rates and total water use were forecasted to decrease as economic growth rates increase. Daily per capita rates were expected to decrease as population growth rates increase; however, total water use was less sensitive to population growth rates than daily per capita rates. Effects of climate change were minimal over the 2030 and 2040 forecasting horizon for the scenarios tested.

Rhode Island↗

USGS2000

Simulation of projected water demand and ground-water levels in the Coffee Sand and Eutaw-McShan aquifers in Union County, Mississippi, 2010 through 2050

Ground water from the Eutaw-McShan and the Coffee Sand aquifers is the major source of supply for residential, commercial, and industrial purposes in Union County, Mississippi. Unbiased, scientifically sound data and assessments are needed to assist agencies in better understanding and managing available water resources as continuing development and growth places more stress on available resources. The U.S. Geological Survey, in cooperation with the Tennessee Valley Authority, conducted an investigation using water-demand and ground-water models to evaluate the effect of future water demand on groundwater levels. Data collected for the 12 public-supply facilities and the self-supplied commercial and industrial facilities in Union County were used to construct water-demand models. The estimates of water demand to year 2050 were then input to a ground-water model based on the U.S. Geological Survey finite-difference computer code, MODFLOW. Total ground-water withdrawals for Union County in 1998 were estimated as 2.85 million gallons per day (Mgal/d). Of that amount, municipal withdrawals were 2.55 Mgal/d with about 1.50 Mgal/d (59 percent) delivered to residential users. Nonmunicipal withdrawals were 0.296 Mgal/d. About 80 percent (2.27 Mgal/d) of the total ground-water withdrawal is produced from the Eutaw-McShan aquifer and about 13 percent (0.371 Mgal/d) from the Coffee Sand aquifer. Between normal- and high-growth conditions, total water demand could increase from 72 to 131 percent (2.9 Mgal/d in 1998 to 6.7 Mgal/d in year 2050) with municipal demand increasing from 77 to 146 percent (2.6 to 6.4 Mgal/d). Increased pumping to meet the demand for water was simulated to determine the effect on water levels in the Coffee Sand and Eutaw- McShan aquifers. Under baseline-growth conditions, increased water use by year 2050 could result in an additional 65 feet of drawdown in the New Albany area below year 2000 water levels in the Coffee Sand aquifer and about 120 feet of maximum drawdown in the Eutaw-McShan aquifer. Under normal-growth conditions, increased water use could result in an additional 65 feet of drawdown in the New Albany area below year 2000 water levels in the Coffee Sand aquifer and about 135 feet of maximum drawdown in the Eutaw-McShan aquifer. Under high-growth conditions, increased water use could result in 75 feet of drawdown in the New Albany area below year 2000 water levels in the Coffee Sand aquifer and about 190 feet of maximum drawdown in the Eutaw-McShan aquifer. The resulting highgrowth projected water level for the year 2050 at the center of the drawdown cone in the New Albany area is between 450 and 500 feet above the top of the Eutaw-McShan aquifer.

Mississippi↗

USGS2002

Food limitation and the recovery of sea otters following the 'Exxon Valdez' oil spill

We examined the potential role of food limitation in constraining the recovery of sea otters Enhydra lutris in Prince William Sound, Alaska, following the 'Exxon Valdez' oil spill. The spill resulted in the removal of a large number of sea otters in 1989, and as of 1998, the portion of the population in the heavily oiled northern Knight Island region had not fully recovered. Between 1996 and 1998, prey consumption rate was higher and the condition of sea otters was better at northern Knight Island than in an unoiled area of the sound (Montague Island). Estimates of prey energy available per unit mass of sea otter were about 4 times higher at Knight than Montague Island, albeit not significantly different between the 2 areas. Over this same period, the number of sea otters remained constant at northern Knight Island but increased at Montague Island. These data suggest that food was at least as abundant at Knight than at Montague Island, and that recovery of sea otters via intrinsic population growth was limited by factors other than food. However, the availability of food, the prey consumption rate, and the condition of sea otters were all much lower at both Knight and Montague Islands than in areas newly occupied by sea otters where the population growth rate was near the theoretical maximum. It is possible that the relatively short supply of food (compared to areas where sea otter population growth rate was high) may have inhibited immigration or interacted with other factors (e.g. oil-induced mortality or predation) to restrict sea otter population growth. Nonetheless, these data suggest that impacts of anthropogenic disturbances on large, often food-limited vertebrate predators can persist in spite of the availability of food resources that are sufficient for intrinsic population growth.

Alaska↗

USGS1974

Studies on the riboflavin, niacin, pantothenic acid and choline requirements of young Bobwhite quail

Four experiments were conducted to examine the riboflavin, niacin, pantothenic acid and choline requirements of young Bobwhite quail. Quail fed purified diets deficient in either riboflavin, niacin, pantothenic acid or choline grew poorly and high mortality occurred by 5 weeks of age. Under the conditions of these experiments, it was found that: (1) young quail require approximately 3.8 mg. riboflavin/kg. diet for satisfactory growth and survival; (2) no more than 31 mg. niacin/kg. diet are required for normal growth and survival of young quail; (3) the requirement for pantothenic acid is higher than has previously been reported, quail in these studies requiring 12.6 mg. pantothenic acid/kg. feed for growth and survival; and (4) the requirement for choline for reducing mortality is approximately 1000 mg./kg., while the amount necessary for normal growth of young quail is no greater than 1500 mg./kg. when the diet contains ample amounts of methionine. Quail fed a niacin-deficient diet developed stiff, shortened feathers and an erythema about the head; those receiving a riboflavin-deficient ration developed enlarged hocks and bowed legs, as did quail fed diets low or devoid of choline. Aside from slow growth, poor feathering was the only other indication that a deficient diet was being fed when quail were placed on a basal ration without pantothenic acid for five weeks.

Poultry Science↗

USGS2020

Density dependence and adult survival drive the dynamics in two high elevation amphibian populations

Amphibian conservation has progressed from the identification of declines to mitigation, but efforts are hampered by the lack of nuanced information about the effects of environmental characteristics and stressors on mechanistic processes of population regulation. Challenges include a paucity of long-term data and scant information about the relative roles of extrinsic (e.g., weather) and intrinsic (e.g., density dependence) factors. We used a Bayesian formulation of an open population capture-recapture model and >30 years of data to examine intrinsic and extrinsic factors regulating two adult boreal chorus frogs ( Pseudacris maculata ) populations. We modelled population growth rate and apparent survival directly, assessed their temporal variability, and derived estimates of recruitment. Populations were relatively stable (geometric mean population growth rate >1) and regulated by negative density dependence (i.e., higher population sizes reduced population growth rate). In the smaller population, density dependence also acted on adult survival. In the larger population, higher population growth was associated with warmer autumns. Survival estimates ranged from 0.30–0.87, per-capita recruitment was <1 in most years, and mean seniority probability was >0.50, suggesting adult survival is more important to population growth than recruitment. Our analysis indicates density dependence is a primary driver of population dynamics for P. maculata adults.

Colorado↗

USGS2022

Population dynamics of Yellowstone Cutthroat Trout in Henrys Lake, Idaho

Yellowstone Cutthroat Trout (YCT) Oncorhynchus clarkii bouvieri is a species with significant ecological and recreational value. In many YCT fisheries, managers are tasked with balancing angler expectations and fish conservation. Henrys Lake supports a popular trophy trout fishery, but the increase of nonnative Utah Chub Gila atraria has caused concern for YCT. We summarized long-term trends in abundance, length structure, body condition, and growth of YCT to evaluate the effect of Utah Chub. Additionally, we investigated abiotic and biotic factors influencing YCT. We examined archived hard structures to provide a comprehensive evaluation of changes in age and growth of YCT in the system. We used stocking records and catch rates of Utah Chub and trout in Henrys Lake as covariates to explain changes in YCT catch rates and growth. Catch rates varied from 1.5 to 15.4 YCT per net night during the 2002 to 2020 sampling period, but we did not identify consistent patterns. Length structure was consistently dominated by stock- to quality-length fish, and we captured few fish >600 mm in total length. Relative weight of YCT was decreased from a mean ± standard deviation (SD) of 115.9 ± 16.5 in 2004 to 93.2 ± 8.2 in 2020. The age of YCT varied between 1 and 11 years; fish that we captured during 2010 to 2020 were the oldest. The majority of fish that we sampled were age 4 and younger. Total annual mortality of age-2 and older YCT was higher than other Cutthroat Trout populations (i.e., 0.70 during 2002 to 2010 and 0.60 during 2011 to 2020). Based on regression models, we identified positive relationships between catch rates of YCT, Brook Trout Salvelinus fontinalis, and Rainbow Trout Oncorhynchus mykiss × YCT hybrid trout. We observed negative relationships between growth of YCT and abundance of Utah Chub and Brook Trout. Although we identified negative relationships, YCT growth in recent decades is as fast as or faster than earlier time periods. Results from this research suggest that major changes in YCT population dynamics are not evident over the last 20 years. This study provides insight into the factors influencing an adfluvial trout population. In particular, results from this research may be useful for managers of systems where Utah Chub have been introduced.

Idaho↗

USGS2009

Why are diverse relationships observed between phytoplankton biomass and transport time?

Transport time scales such as flushing time and residence time are often used to explain variability in phytoplankton biomass. In many cases, empirical data are consistent with a positive phytoplankton‐transport time relationship (i.e., phytoplankton biomass increases as transport time increases). However, negative relationships, varying relationships, or no significant relationship may also be observed. We present a simple conceptual model, in both mathematical and graphical form, to help explain why phytoplankton may have a range of relationships with transport time, and we apply it to several real systems. The phytoplankton growth‐loss balance determines whether phytoplankton biomass increases with, decreases with, or is insensitive to transport time. If algal growth is faster than loss (e.g., grazing, sedimentation), then phytoplankton biomass increases with increasing transport time. If loss is faster than growth, phytoplankton biomass decreases with increasing transport time. If growth and loss are approximately balanced, then phytoplankton biomass is relatively insensitive to transport time. In analyses of several systems, portions of an individual system, or time periods, apparent insensitivity of phytoplankton biomass to changes in transport time could arise due to the superposition of cases with different phytoplankton‐transport time relationships. Thus, in order to understand or predict responses of phytoplankton biomass to changes in transport time, the relative rates of algal growth and loss must be known.

Limnology and Oceanography↗

USGS2006

Evaluation of a lake whitefish bioenergetics model

We evaluated the Wisconsin bioenergetics model for lake whitefish Coregonus clupeaformis in the laboratory and in the field. For the laboratory evaluation, lake whitefish were fed rainbow smelt Osmerus mordax in four laboratory tanks during a 133-d experiment. Based on a comparison of bioenergetics model predictions of lake whitefish food consumption and growth with observed consumption and growth, we concluded that the bioenergetics model furnished significantly biased estimates of both food consumption and growth. On average, the model overestimated consumption by 61% and underestimated growth by 16%. The source of the bias was probably an overestimation of the respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit of the model to the observed consumption and growth in our laboratory tanks. Based on the adjusted model, predictions of food consumption over the 133-d period fell within 5% of observed consumption in three of the four tanks and within 9% of observed consumption in the remaining tank. We used polychlorinated biphenyls (PCBs) as a tracer to evaluate model performance in the field. Based on our laboratory experiment, the efficiency with which lake whitefish retained PCBs from their food (I?) was estimated at 0.45. We applied the bioenergetics model to Lake Michigan lake whitefish and then used PCB determinations of both lake whitefish and their prey from Lake Michigan to estimate p in the field. Application of the original model to Lake Michigan lake whitefish yielded a field estimate of 0.28, implying that the original formulation of the model overestimated consumption in Lake Michigan by 61%. Application of the bioenergetics model with the adjusted respiration component resulted in a field I? estimate of 0.56, implying that this revised model underestimated consumption by 20%.

Transactions of the American Fisheries Society↗

USGS2005

The role of fire in shaping avian communities in sagebrush ecosystems

Studies in Avian Biology↗

USGS2005

Approaches for the direct estimation of rate of increase in population size using capture-recapture data

Recent developments in the modeling of capture-recapture data permit the direct estimation and modeling of population growth rate Pradel (1996). Resulting estimates reflect changes in numbers of birds on study areas, and such changes result from movement as well as survival and reproductive recruitment. One measure of the 'importance' of a demographic vital rate to population growth is based on temporal covariation (i.e., do changes in population growth follow changes in vital rates). If data are available to estimate vital rates or their components, then such data can be combined with capture-recapture data in order to estimate parameters of the relationship between population growth and the vital rate. These methods are illustrated using capture-recapture and nest observation data for Black-throated Blue Warblers, Dendroica caerulescens, from a long-term study at Hubbard Brook Experimental Forest, New Hampshire, USA. Population growth rate was found to be positively associated with the proportion of birds that double-brood. We encourage use of these methods and believe they will prove to be very useful in research on, and management of, migratory bird populations.

Book chapter↗

USGS1979

Feeding ecology and development of juvenile black ducks in Maine

Data from 41 juvenile Black Ducks ( Anas rubripes ) collected in the Penobscot River valley of Maine from June through August 1974-76 were used to estimate the proportion of aquatic invertebrates in the prefledging diet and the allometric growth rates of the tarsi, flight muscles, and alimentary system. The proportion of aquatic invertebrates in the diet of downy and partially feathered juveniles averaged 88 and 91% of dry weight, but decreased to 43% for fully feathered young. The most important invertebrate food organisms for juvenile Black Ducks were asellid isopods, molluscs, nymphs of Ephemeroptera and Odonata, and larvae of Coleoptera, Trichoptera, and Diptera. A high proportion of invertebrates was consumed during the period of fastest absolute and relative growth. Estimation of allometric growth rates with the power formula (Y = a·$X_{b}$) showed that (1) the legs were relatively large at hatching and developed slowly; (2) the flight muscles, which were relatively small at hatching, grew slowly until the 4-week period preceding fledging, when they increased as the 4.75 power of body weight; and (3) growth of the liver and gizzard was approximately proportional to body weight. The data support Ricklefs' thesis that delayed functional maturity of the wings permits an increase in the overall growth rate of waterfowl.

The Auk↗

USGS2000

Effects of feeding ration on larval swimming speed and responsiveness to predator attacks: Implications for cohort survival

We conducted laboratory experiments to examine the effects of feeding ration on the routine swimming speed of larval striped bass (Morone saxatilis) and their responsiveness to simulated-predator attacks. Striped bass were reared in low (7 prey ?? L-1), medium (354 prey ?? L-1), or high (740 prey ?? L-1) prey treatments from age 4 to 14 days posthatch. Larvae reared in the low-prey treatment had slower routine swimming speeds and shorter reactive distances and were less responsive to simulated-predator attacks. These differences were most pronounced after age 10 and appeared to be an effect of deteriorating larval condition rather than an effect of size. Simulation models were constructed for two potential fish predators, Alosa aestivalis and Pomoxis nigromaculatus, to examine how variation in growth rate, swimming speed, and responsiveness to predator attacks might influence mortality rate. Our simulations predicted that cohort mortality rate would decrease with increasing larval growth rates, even though faster routine swimming speed and growth rate increased encounter rates with predators. The influence of larval growth rate and responsiveness on mortality rate varied between the two predators, but cohorts experiencing no growth always had the greatest mortality rate.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2002

Temperature history of Coregonus artedi in the St. Marys River, Laurentian Great Lakes, inferred from oxygen isotopes in otoliths

The population of Coregonus artedi in the St. Marys River, between lakes Superior and Huron, was sampled and otoliths were analyzed for oxygen isotopic composition to determine whether the fish are residents in the St. Marys River and its warm bays or migrants to and from cold Lake Huron. Otoliths were extracted, sectioned, and growth ring-specific samples of calcium carbonate were milled to obtain samples for determination of oxygen isotope ratios (18O values). The 18O values of calcium carbonate (CaCO3) in accretionary structures such as otoliths allow calculation of growth temperatures of the fish, because of differential fractionation of oxygen isotopes at different temperatures. Growth temperatures of 10 St. Marys River lake herring were compared with lake and catch data as well as growth temperatures of lake herring collected from Lake Huron and other ciscoes from the Great Lakes. Results of this analysis indicate that these fish remained in the bays of the St. Marys River for their entire life history. After their second year they grew at average temperatures between 11 C and 13 C, consistent with temperature in the warmer bays of the St. Marys River and 6 C higher than expected for growth of this species in Lake Huron.

St. Marys River↗

USGS2006

Impact of quaternary climate on seepage at Yucca Mountain, Nevada

Uranium-series ages, oxygen-isotopic compositions, and uranium contents were determined in outer growth layers of opal and calcitefrom 0.5- to 3-centimeter-thick mineral coatings hosted by lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a permanent repository for high-level radioactive waste. Micrometer-scale growth layering in the minerals was imaged using a cathodoluminescence detector on a scanning electron microscope. Determinations of the chemistry, ages, and delta oxygen-18 (??18O) values of the growth layers were conducted by electron microprobe analysis and secondary ion mass spectrometry techniques at spatial resolutions of 2 to about 20 micrometers (??m) and 25 to 40 ??m, respectively. Growth rates for the last 300 thousand years (k.y.) calculated from about 300 new high-resolution uranium-series ages range from approximately 0.5 to 1.5 ??m/k.y. for 1- to 3-centimeter-thick coatings, whereas coatings less than about 1-centimeter-thick have growth rates less than 0.5 ??m/k.y. At the depth of the proposed repository, correlations of uranium concentration and ??18O values with regional climate records indicate that unsaturated zone percolation and seepage water chemistries have responded to changes in climate during the last several hundred thousand years.

Conference Paper↗

USGS2013

Ecosystem stressors in southern Nevada

Southern Nevada ecosystems and their associated resources are subject to a number of global and regional/local stressors that are affecting the sustainability of the region. Global stressors include elevated carbon dioxide (CO 2 ) concentrations and associated changes in temperature and precipitation patterns and amount, solar radiation, and nutrient cycles (Smith and others 2009b). Global stressors are ubiquitous in nature and interact both directly and indirectly with regional or local stressors. Regional/local stressors in southern Nevada include: population growth and urbanization and associated increases in nitrogen deposition, energy development, water development, and recreation; increased effects of insects and disease; ongoing effects of livestock, wild horse and burro grazing; new and expanding invasive species; and altered fire regimes. This chapter provides background information on the stressors affecting southern Nevada's ecosystems that is needed to address Goal 1.0 in the SNAP Science Research Strategy, which is to restore, sustain, and enhance southern Nevada's ecosystems (Turner and others 2009). Human population growth and changes in land use strongly affect the type and magnitude of local/regional stressors. From 1960 to 2010, Nevada's growth rate was the highest in the nation (www.census.gov/prod/cen2010/briefs/c2010br-01.pdf). Clark County has experienced particularly high growth, with a population increase of greater than 40 percent since the 2000 census. Factors like land ownership, historic and current land use, proximity to human and energy developments, and desirability for recreation all influence the level of human-caused stress. The strong elevation/climate gradients and large difference in the environmental characteristics of southern Nevada ecosystems (fig. 1.2; Chapter 1) have a major influence on both patterns of land use and the dominant stressors for different ecosystem types. Shifts in land use related to population growth, urbanization, and energy development and largely focused in lower elevation ecosystems including sagebursh, blackbrush and shadscale, and Mojave Desert scrub. Water divisions influence riparian/aquatic ecosystems and springs, while groundwater pumping also has the potential to affect ecosystems that characterize lower valleys including Mojave Desert scrub. Recreational uses influence all ecosystems, and wild horse and burro use and livestock grazing affect all but alpine and subalpine ecosystems. Insects and disease, as well as invasive species are widespread stressors. Fire is limited to ecosystems with sufficient fuels to carry fire and is strongly influence by invasive species in lower elevation Mojave Desert scrub, blackbrush and shadscale, and sagebursh ecosystems. This chapter address aspects of several of the Goals and Sub-goals listed in the SNAP Science Research Strategy (table 1.3; Turner and others 2009). Altered fire regimes, invasive species, land use practices, and management actions are addressed in Goal 1 -- Sustain, Restore, and Enhance Southern Nevada's Ecosystems. The effects of these stressors on sensitive species and habitat are specifically addressed in Sub-goal 1.4 -- Sustain and Enhance Southern Nevada's Biotic Communities, to Preserve Biodiversity and Maintain Populations. Anthropogenic factors, such a recreation and urbanization, are referred to in Goal 2-- Provide for Responsible Use of Southern Nevada;s Lands in a Manner that Preserve Heritage Resources and Promotes an Understanding of Human Interaction with the Landscape.

Nevada↗

USGS1960

Geology and ground-water resources of the island of Kauai, Hawaii

Kauai is one of the oldest, and is structurally the most complicated, of the Hawaiian Islands. Like the others, it consists principally of a huge shield volcano, built up from the sea floor by many thousands of thin flows of basaltic lava. The volume of the Kauai shield was on the order of 1,000 cubic miles. Through much of its growth it must have resembled rather closely the presently active shield volcano Mauna Loa, on the island of Hawaii. When the Kauai volcano started its growth is not known with certainty, but it is believed that activity started late in the Tertiary period, possibly in the early or middle part of the Pliocene epoch. Growth of the shield was rapid and probably was completed before the end of the Pliocene. Toward the end of the growth of the shield, its summit collapsed to form a broad caldera, the largest that has been found in the Hawaiian Islands. Like the calderas of Kilauea and Mauna Loa, that of Kauai volcano had boundaries that were, in part, rather indefinite. The principal depression was bordered by less depressed fault blocks, some of which merged imperceptibly with the outer slopes of the volcano. Elsewhere the caldera rim was low, and flows spilled over it onto the outer slopes. The well-defined central depression of the Kauai caldera was approximately 10 to 12 miles across. At about the same time as the formation of the major caldera, another, smaller caldera was formed by collapse around a minor eruptive center on the southeastern side of the Kauai shield. Lavas accumulated in the calderas, gradually filling them and burying banks of talus that formed along the foot of the boundary cliffs. The caldera-filling lavas differed from those that built the major portion of the shield in being much thicker and more massive as a result of ponding in the depressions. The petrographic types for the most part are the same throughout. Both the flank flows that built most of the shield and the flows that filled the calderas are predominantly olivine basalt. Picrite-basalt (oceanite), containing very abundant large phenocrysts of olivine, and basalt containing little or no olivine are present but together comprise less than 10 percent of the whole. Late in the period of filling of the major caldera a small amount of basaltic andesine andesite was extruded. Near the end of the period of filling of the major caldera further collapse occurred, forming a large graben on the southwestern side of the shield. Lava flows erupting within the caldera poured southwestward over the cliff bounding the graben and spread over the gently sloping graben floor. Near the present Waimea Canyon their advance was obstructed by the fault scarp at the west edge of the graben. The cliff along the northeast edge of the graben eventually was buried by lava flows from within the caldera, but that along the west edge continued to stand above the level of the flows in the graben. The flows that accumulated in the graben are of the same types as those that filled the caldera, and like them are mostly thick and massive because of ponding by the graben walls and of the gentle slopes of the graben floor over which they spread. The rocks of the major Kauai shield volcano are known as the Waimea Canyon volcanic series. The thin flows that accumulated on the flanks of the shield, which compose the major portion of the volcanic edifice, are named the Napali formation of the Waimea Canyon volcanic series. The rocks that accumulated in the big summit caldera are named the Olokele formation, and those that filled the small caldera on the southeast flank of the shield are named the Haupu formation. The volcanic rocks accumulated in the graben on the southwestern side of the shield are named the Makaweli formation of the Waimea Canyon volcanic series, and sedimentary rocks interbedded with them are known as the Mokuone member of the Makaweli formation. Few vents of the Waimea Canyon volcanic series have been recognized, probably because most of them have been destroyed by erosion or are buried by later lavas. Large numbers of dikes cut the lavas of the Napali formation along Waimea Canyon and the Napali Coast and along the east edge of the Waialeale massif. Fewer dikes are found in the other members of the series. Some tendency toward radial arrangement of the dikes is present, but the dominant trend all over the island is east-northeastward. Another great collapse took place on the eastern flank of the volcano at about the time the major shield became extinct, or shortly afterward. A subcircular graben 6 or 7 miles across sank several thousand feet, forming a broad depression between the Waialeale massif on the west and Kalepa and Nonou ridges on the east. This collapsed structure cannot be as clearly demonstrated as the Makaweli graben on the southwest side of the shield, because its walls have been greatly eroded and its floor is deeply buried by lavas of the later Koloa volcanic series. It appears, however, to be the only reasonable explanation of the physiography of the eastern side of the island. After the completion of the great Kauai shield came a long period of erosion during which no volcanic activity occurred. Waves cut high sea cliffs around the island, and streams cut canyons as much as 3,000 feet deep. Thick soil formed over much of the mountain. Then volcanism was renewed. Eruption occurred from a series of minor vents arranged in nearly north-south and northeast-southwest lines across the eastern two-thirds of the island. The lavas, cinder cones, and ash beds of this period of volcanism are known as the Koloa volcanic series. Lavas of the Koloa volcanic series include olivine basalt, picrite-basalt (mimosite) with few phenocrysts of olivine, basanite, nepheline basalt, melilite-nepheline basalt, and ankaratrite (nepheline basalt very rich in pyroxene and olivine). Inclusions of dunite, composed almost entirely of olivine, are common in flows of the Koloa. Just before and during the eruption of the Koloa volcanic series, voluminous landslides and mudflows brought down a large amount of rock debris and soil from the steep slopes of the mountainous central upland and deposited it as breccias at the foot of the steep slopes in valley heads and along the border of the marginal lowland. Streams distributed part of the material across the lowland. The breccias and conglomerates thus formed, and later buried by lavas of the Koloa volcanic series, are named the Palikea formation of the Koloa volcanic series. The structures formed at Koloa vents include cinder cones, one tuff cone, and lava cones. The latter are miniature shields resembling the major shield volcano, formed by repeated outpourings of fluid lava. The tuff cone, at the west side of Kilauea Bay, was formed by phreatomagmatic explosions caused by rising magma coming in contact with water-saturated rocks. Volcanism during Koloa time continued for a long period but was not continuous over the entire area. Locally, long periods of quiet occurred, allowing streams to re-excavate some of the canyons filled by earlier flows of the Koloa volcanic series, and weathering to form soils later buried by new flows. Some of the canyons thus formed during the time when the Koloa was being deposited were several hundred feet deep. Volcanism probably continued throughout most of the Pleistocene epoch. The latest flow of the Koloa volcanic series appears very recent, and rests on lithified calcareous dunes formed during one of the Pleistocene low stands of the sea. During the Pleistocene epoch stream valleys and sea cliffs were eroded to base levels governed by one or more stands of the sea more than 100 feet below present sea level. Beaches of calcareous sand were formed, and the sand blown inland to form calcareous dunes, now lithified. A test boring near Moloaa penetrated calcareous sand 160 feet below sea level, at the foot of a high sea cliff. Coral reef also was built around part or all of the island, and in part buried by lavas of the Koloa volcanic series. The explosions that built the tuff cone at Kilauea Bay threw up fragments of limestone from a buried reef. Much of the apron of lavas of the Kalna series around the northeastern side of the island probably rests on a platform formed below present sea level by wave erosion and the growth of coral reef. As the sea rose around the island, the valley mouths were alluviated. Several levels of the sea higher than the present one probably are represented. Some stream terraces may be graded to a stand of the sea as high as 260 feet above present sea level, but no positive evidence for stands higher than 25 feet have been found. Well-preserved shorelines are recognized approximately 25 and 5 feet above sea level. Much of the present coral reef appears to have been formed when the sea stood about 5 feet higher than now, and reduced to its present level by solutional weathering and wave erosion. The lavas of the Napali formation of the Waimea Canyon volcanic series are highly permeable. They carry basal water over much of the island, and yield it freely to wells. This water is fresh everywhere except very close to the coast on the leeward side of the island. In some areas they may contain water confined at high levels between dikes. The lavas of the Olokele and Haupu formations are moderately to poorly permeable. They probably contain fresh water at sea level, but would not yield it readily to wells. Locally, ash beds perch small bodies of fresh water at high levels in the lavas of the Olokele formation, but these are of no economic importance. The lavas of the Makaweli formation also arc moderately to poorly permeable. They carry fresh or brackish water at sea level. In general, they yield water to wells less readily than the lavas of the Napali formation, but more readily than the lavas of the Olokele. The conglomerates and breccias of the Mokuone member are poorly permeable, but are not known to perch more than a slight amount of water in the overlying lavas, The lava flows of the Koloa volcanic series are poorly to moderately permeable. They carry fresh or brackish water at sea level, but generally yield it slowly to wells. Locally, small bodies of fresh water are perched at high levels in the lavas of the Koloa by beds of ash and soil and by breccia and conglomerate of the Palikea formation. Both the older and the younger alluvium generally are poorly permeable, but contain small amounts of fresh or brackish water. The lithified calcareous dunes are permeable, but they appear to contain only brackish water. Lagoon deposits on the Mana plain are poorly to moderately permeable and yield brackish water to wells.

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