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Year Published: 2014

An analysis of the potential for Glen Canyon Dam releases to inundate archaeological sites in the Grand Canyon, Arizona

The development of a one-dimensional flow-routing model for the Colorado River between Lees Ferry and Diamond Creek, Arizona in 2008 provided a potentially useful tool for assessing the degree to which varying discharges from Glen Canyon Dam may inundate terrestrial environments and potentially affect resources located within the zone of...

Sondossi, Hoda A.; Fairley, Helen C.
An analysis of the potential for Glen Canyon Dam releases to inundate archaeological sites in the Grand Canyon, Arizona; 2014; OFR; 2014-1193; Sondossi, Hoda A.; Fairley, Helen C.

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Year Published: 2014

Extracellular enzyme kinetics scale with resource availability

Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimilation of carbon, nitrogen and phosphorus by diverse aquatic and...

Sinsabaugh, Robert L.; Belnap, Jayne; Findlay, Stuart G.; Follstad Shah, Jennifer J.; Hill, Brian H.; Kuehn, Kevin A.; Kuske, Cheryl; Litvak, Marcy E.; Martinez, Noelle G.; Moorhead, Daryl L.; Warnock, Daniel D.
Extracellular enzyme kinetics scale with resource availability; 2014; Article; Journal; Biogeochemistry; Sinsabaugh, Robert L.; Belnap, Jayne; Findlay, Stuart G.; Follstad Shah, Jennifer J.; Hill, Brian H.; Kuehn, Kevin A.; Kuske, Cheryl; Litvak, Marcy E.; Martinez, Noelle G.; Moorhead, Daryl L.; Warnock, Daniel D.

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Year Published: 2014

Water-chemistry data collected in and near Kaloko-Honokohau National Historical Park, Hawaii, 2012–2014

Kaloko-Honokōhau National Historical Park (KAHO) on western Hawaiʻi was established in 1978 to preserve, interpret, and perpetuate traditional Native Hawaiian culture and activities, including the preservation of a variety of culturally and ecologically significant water resources that are vital to this mission. KAHO water bodies provide habitat...

Tillman, Fred D.; Oki, Delwyn S.; Johnson, Adam G.
Water-chemistry data collected in and near Kaloko-Honokohau National Historical Park, Hawaii, 2012–2014; 2014; OFR; 2014-1173; Tillman, Fred D.; Oki, Delwyn S.; Johnson, Adam G.

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Year Published: 2014

Sediment and water chemistry of the San Juan River and Escalante River deltas of Lake Powell, Utah, 2010-2011

Recent studies have documented the presence of trace elements, organic compounds including polycyclic aromatic hydrocarbons, and radionuclides in sediment from the Colorado River delta and from sediment in some side canyons in Lake Powell, Utah and Arizona. The fate of many of these contaminants is of significant concern to the resource managers...

Hornewer, Nancy J.
Sediment and water chemistry of the San Juan River and Escalante River deltas of Lake Powell, Utah, 2010-2011; 2014; OFR; 2014-1096; Hornewer, Nancy J.

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Year Published: 2014

Updated estimates of long-term average dissolved-solids loading in streams and rivers of the Upper Colorado River Basin

The Colorado River and its tributaries supply water to more than 35 million people in the United States and 3 million people in Mexico, irrigating over 4.5 million acres of farmland, and annually generating about 12 billion kilowatt hours of hydroelectric power. The Upper Colorado River Basin, part of the Colorado River Basin, encompasses more...

Tillman, Fred D.; Anning, David W.
Updated estimates of long-term average dissolved-solids loading in streams and rivers of the Upper Colorado River Basin; 2014; OFR; 2014-1148; Tillman, Fred D.; Anning, David W.

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Year Published: 2014

Initial soil respiration response to biomass harvesting and green-tree retention in aspen-dominated forests of the Great Lakes region

Contemporary forest management practices are increasingly designed to optimize novel objectives, such as maximizing biomass feedstocks and/or maintaining ecological legacies, but many uncertainties exist regarding how these practices influence forest carbon (C) cycling. We examined the responses of soil respiration (Rs) to biomass harvesting and...

Kurth, Valerie J.; Bradford, John B.; Slesak, Robert A.; D'Amato, Anthony W.
Initial soil respiration response to biomass harvesting and green-tree retention in aspen-dominated forests of the Great Lakes region; 2014; Article; Journal; Forest Ecology and Management; Kurth, Valerie J.; Bradford, John B.; Slesak, Robert A.; D'Amato, Anthony W.

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Year Published: 2014

Forest stand structure, productivity, and age mediate climatic effects on aspen decline

Because forest stand structure, age, and productivity can mediate the impacts of climate on quaking aspen (Populus tremuloides) mortality, ignoring stand-scale factors limits inference on the drivers of recent sudden aspen decline. Using the proportion of aspen trees that were dead as an index of recent mortality at 841 forest inventory plots, we...

Bell, David M.; Bradford, John B.; Lauenroth, William K.
Forest stand structure, productivity, and age mediate climatic effects on aspen decline; 2014; Article; Journal; Ecology; Bell, David M.; Bradford, John B.; Lauenroth, William K.

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Year Published: 2014

Emplacement and erosive effects of the south Kasei Valles lava on Mars

Although it has generally been accepted that the Martian outflow channels were carved by floods of water, observations of large channels on Venus and Mercury demonstrate that lava flows can cause substantial erosion. Recent observations of large lava flows within outflow channels on Mars have revived discussion of the hypothesis that the Martian...

Dundas, Colin M.; Keszthelyi, Laszlo P.

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Year Published: 2014

High manganese concentrations in rocks at Gale crater, Mars

The surface of Mars has long been considered a relatively oxidizing environment, an idea supported by the abundance of ferric iron phases observed there. However, compared to iron, manganese is sensitive only to high redox potential oxidants, and when concentrated in rocks, it provides a more specific redox indicator of aqueous environments....

Lanza, Nina L.; Fischer, Woodward W.; Wiens, Roger C.; Grotzinger, John P.; Ollila, Ann M.; Anderson, Ryan B.; Clark, Benton C.; Gellert, Ralf; Mangold, Nicolas; Maurice, Sylvestre; Le Mouélic, Stéphane; Nachon, Marion; Schmidt, Mariek E.; Berger, Jeffrey; Clegg, Samuel M.; Forni, Olivier; Hardgrove, Craig; Melikechi, Noureddine; Newsom, Horton E.; Sautter, Violaine
Lanza, Nina L., Fischer, Woodward W., Wiens, Roger C., Grotzinger, John, Ollila, Ann M., Cousin, Agnes, Anderson, Ryan B., Clark, Benton C., Gellert, Ralf, Mangold, Nicolas, Maurice, Sylvestre, Le Mouélic, Stéphane, Nachon, Marion, Schmidt, Mariek, Berger, Jeffrey, Clegg, Samuel M., Forni, Olivier, Hardgrove, Craig, Melikechi, Noureddine, Newsom, Horton E., and Sautter, Violaine, 2014, High manganese concentrations in rocks at Gale crater, Mars, Geophysical Research Letters, doi:10.1002/2014GL060329

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Year Published: 2014

Colorado River campsite monitoring, Grand Canyon National Park, Arizona, 1998-2012

River rafting trips and hikers use sandbars along the Colorado River in Marble and Grand Canyons as campsites. The U.S. Geological Survey evaluated the effects of Glen Canyon Dam operations on campsite areas on sandbars along the Colorado River in Grand Canyon National Park. Campsite area was measured annually from 1998 to 2012 at 37 study sites...

Kaplinski, Matt; Hazel, Joe; Parnell, Rod; Hadley, Daniel R.; Grams, Paul
Colorado River campsite monitoring, Grand Canyon National Park, Arizona, 1998-2012; 2014; OFR; 2014-1161; Kaplinski, Matt; Hazel, Joe; Parnell, Rod; Hadley, Daniel R.; Grams, Paul

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Year Published: 2014

Design of a sediment-monitoring gaging network on ephemeral tributaries of the Colorado River in Glen, Marble, and Grand Canyons, Arizona

Management of sediment in rivers downstream from dams requires knowledge of both the sediment supply and downstream sediment transport. In some dam-regulated rivers, the amount of sediment supplied by easily measured major tributaries may overwhelm the amount of sediment supplied by the more difficult to measure lesser tributaries. In this first...

Griffiths, Ronald E.; Topping, David J.; Anderson, Robert S.; Hancock, Gregory S.; Melis, Theodore S.
Design of a sediment-monitoring gaging network on ephemeral tributaries of the Colorado River in Glen, Marble, and Grand Canyons, Arizona; 2014; OFR; 2014-1137; Griffiths, Ronald E.; Topping, David J.; Anderson, Robert S.; Hancock, Gregory S.; Melis, Theodore S.

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Year Published: 2014

High diet overlap between native small-bodied fishes and nonnative fathead minnow in the Colorado River, Grand Canyon, Arizona

River regulation may mediate the interactions among native and nonnative species, potentially favoring nonnative species and contributing to the decline of native populations. We examined food resource use and diet overlap among small-bodied fishes in the Grand Canyon section of the Colorado River as a first step in evaluating potential resource...

Seegert, Sarah E. Zahn; Rosi-Marshall, Emma J.; Baxter, Colden V.; Kennedy, Theodore A.; Hall, Robert O.; Cross, Wyatt F.
High diet overlap between native small-bodied fishes and nonnative fathead minnow in the Colorado River, Grand Canyon, Arizona; 2014; Article; Journal; Transactions of the American Fisheries Society; Seegert, Sarah E. Zahn; Rosi-Marshall, Emma J.; Baxter, Colden V.; Kennedy, Theodore A.; Hall, Robert O., Jr.; Cross, Wyatt F.

Nine USGS Science Centers are administered by the Pacific Regional office, which is headquartered in Sacramento, California.