Phylogenetic evidence for an ancient rapid radiation of Caribbean sponge-dwelling snapping shrimps (Synalpheus)
C.L. Morrison, R. Rios, J.E. Duffy
2004, Molecular Phylogenetics and Evolution (30) 563-581
A common challenge in reconstructing phylogenies involves a high frequency of short internal branches, which makes basal relationships difficult to resolve. Often it is not clear whether this pattern results from insufficient or inappropriate data, versus from a rapid evolutionary radiation. The snapping shrimp genus Synalpheus, which contains in excess...
Stress triggering in thrust and subduction earthquakes and stress interaction between the southern San Andreas and nearby thrust and strike-slip faults
J. Lin, R.S. Stein
2004, Journal of Geophysical Research B: Solid Earth (109)
We argue that key features of thrust earthquake triggering, inhibition, and clustering can be explained by Coulomb stress changes, which we illustrate by a suite of representative models and by detailed examples. Whereas slip on surface-cutting thrust faults drops the stress in most of the adjacent crust, slip on blind...
Stable isotopic constraints on fluid-rock interaction and Cu-PGE-S redistribution in the Sonju Lake intrusion, Minnesota
Y.-R. Park, E.M. Ripley, J.D. Miller Jr., C. Li, J. Mariga, P. Shafer
2004, Economic Geology (99) 325-338
The Sonju Lake intrusion, part of the 1.1 Ga Midcontinent rift-related Beaver Bay Complex, is a 1,200-m-thick, strongly differentiated, layered sequence of mafic cumulates located in northeastern Minnesota. Basal melatroctolite and dunite layers are overlain by troctolite, gabbro, Fe-Ti oxide-rich gabbro, apatite diorite, and monzodiorite. Stratigraphic intervals rich in Pt...
Mineralization and nitrification patterns at eight northeastern USA forested research sites
D.S. Ross, G.B. Lawrence, G. Fredriksen
2004, Forest Ecology and Management (188) 317-335
Nitrogen transformation rates in eight northeastern US research sites were measured in soil samples taken in the early season of 2000 and the late season of 2001. Net mineralization and nitrification rates were determined on Oa or A horizon samples by two different sampling methods - intact cores and repeated...
Role of Microbes in the Smectite-to-Illite Reaction
J. Kim, H. Dong, J. Seabaugh, Steven W. Newell, D. D. Eberl
2004, Science (303) 830-832
Temperature, pressure, and time have been thought to control the smectiteto-illite (S-I) reaction, an important diagenetic process used for petroleum exploration. We demonstrated that microorganisms can promote the S-I reaction by dissolving smectite through reduction of structural FE(III) at room temperature and 1 atmosphere within 14 days. This reaction typically...
Swimming endurance of bull trout, lake trout, arctic char, and rainbow trout following challenge with Renibacterium salmoninarum
D.T. Jones, C.M. Moffitt
2004, Journal of Aquatic Animal Health (16) 10-22
We tested the swimming endurance of juvenile bull trout Salvelinus confluentus, lake trout S. namaycush, Arctic char S. alpinus, and rainbow trout Oncorhynchus mykiss at 9°C and 15°C to determine whether sublethal infection from a moderate challenge of Renibacterium salmoninarum administered months before testing affected the length of time fish...
Modeling sorption of divalent metal cations on hydrous manganese oxide using the diffuse double layer model
J.W. Tonkin, L.S. Balistrieri, J.W. Murray
2004, Applied Geochemistry (19) 29-53
Manganese oxides are important scavengers of trace metals and other contaminants in the environment. The inclusion of Mn oxides in predictive models, however, has been difficult due to the lack of a comprehensive set of sorption reactions consistent with a given surface complexation...
Conservative and reactive solute transport in constructed wetlands
Steffanie H. Keefe, Larry B. Barber, Robert L. Runkel, Joseph N. Ryan, Diane M. McKnight, Roland D. Wass
2004, Water Resources Research (40)
The transport of bromide, a conservative tracer, and rhodamine WT (RWT), a photodegrading tracer, was evaluated in three wastewater‐dependent wetlands near Phoenix, Arizona, using a solute transport model with transient storage. Coupled sodium bromide and RWT tracer tests were performed to establish conservative transport and reactive parameters in constructed wetlands...
Estimating survival and recruitment in a freshwater mussel population using mark-recapture techniques
R.F. Villella, D. R. Smith, D. P. Lemarie
2004, American Midland Naturalist (151) 114-133
We used a mark-recapture method and model averaging to estimate apparent survival, recruitment and rate of population growth in a native freshwater mussel population at a site on the Cacapon River, which is a tributary to the Potomac River. Over 2200 Elliptio complanata, E. fisheriana and Lampsilis cariosa were uniquely...
Estimating tectonic history through basin simulation-enhanced seismic inversion: Geoinformatics for sedimentary basins
K. Tandon, K. Tuncay, K. Hubbard, J. Comer, P. Ortoleva
2004, Geophysical Journal International (156) 129-139
A data assimilation approach is demonstrated whereby seismic inversion is both automated and enhanced using a comprehensive numerical sedimentary basin simulator to study the physics and chemistry of sedimentary basin processes in response to geothermal gradient in much greater detail than previously attempted. The approach not only reduces costs by...
Effect of cell physicochemical characteristics and motility on bacterial transport in groundwater
M.W. Becker, S.A. Collins, D.W. Metge, R.W. Harvey, A.M. Shapiro
2004, Journal of Contaminant Hydrology (69) 195-213
The influence of physicochemical characteristics and motility on bacterial transport in groundwater were examined in flow-through columns. Four strains of bacteria isolated from a crystalline rock groundwater system were investigated, with carboxylate-modified and amidine-modified latex microspheres and bromide as reference tracers. The bacterial isolates included a gram-positive rod (ML1), a...
The nucleus of Comet Borrelly: A study of morphology and surface brightness
J. Oberst, Elpitha Howington-Kraus, Randolph L. Kirk, Laurence A. Soderblom, B. Buratti, M. Hicks, R. Nelson, D. Britt
2004, Icarus (167) 70-79
Stereo images obtained during the DS1 flyby were analyzed to derive a topographic model for the nucleus of Comet 19P/Borrelly for morphologic and photometric studies. The elongated nucleus has an overall concave shape, resembling a peanut, with the lower end tilted towards the camera. The bimodal character of surface-slopes and...
Uptake pathway for Ag bioaccumulation in three benthic invertebrates exposed to contaminated sediments
H. Yoo, J.-S. Lee, B.-G. Lee, I.T. Lee, C.E. Schlekat, C.-H. Koh, S. N. Luoma
2004, Marine Ecology Progress Series (270) 141-152
We exposed 3 benthic invertebrates, the clam Macoma balthica, the polychaete Neanthes arenaceodentataand the amphipod Leptocheirus plumulosus, to Ag-contaminated sediments to evaluate the relative importance of various uptake routes (sediments, porewater or overlying water, and supplementary food) for Ag bioaccumulation. Silver bioaccumulation was evaluated at 4 levels of sediment Ag (0.1, 0,3, 1,2...
Lava lakes on Io: Observations of Io's volcanic activity from Galileo NIMS during the 2001 fly-bys
R. M. C. Lopes, L.W. Kamp, W. D. Smythe, P. Mouginis-Mark, J. Kargel, J. Radebaugh, E. P. Turtle, J. Perry, D.A. Williams, R. W. Carlson, S. Doute
2004, Icarus (169) 140-174
Galileo's Near-Infrared Mapping Spectrometer (NIMS) obtained its final observations of Io during the spacecraft's fly-bys in August (I31) and October 2001 (I32). We present a summary of the observations and results from these last two fly-bys, focusing on the distribution of thermal emission from Io's many volcanic regions that give...
USGS tethered ACP platforms: New design means more safety and accuracy
S. E. Morlock, J. A. Stewart, M.S. Rehmel
2004, Hydro International (8) 45-47
The US Geological Survey has developed an innovative tethered platform that supports an Acoustic Current Profiler (ACP) in making stream-flow measurements (use of the term ACP in this article refers to a class of instruments and not a specific brand name or model). The tethered platform reduces the hazards involved...
Microforms in gravel bed rivers: Formation, disintegration, and effects on bedload transport
K. Strom, A.N. Papanicolaou, N. Evangelopoulos, M. Odeh
2004, Journal of Hydraulic Engineering (130) 554-567
This research aims to advance current knowledge on cluster formation and evolution by tackling some of the aspects associated with cluster microtopography and the effects of clusters on bedload transport. The specific objectives of the study are (1) to identify the bed shear stress range in which clusters form and...
Feasibility of measuring dissolved carbon dioxide based on head space partial pressures
B.J. Watten, C.E. Boyd, M.F. Schwartz, S.T. Summerfelt, B. L. Brazil
2004, Aquacultural Engineering (30) 83-101
We describe an instrument prototype that measures dissolved carbon dioxide (DC) without need for standard wetted probe membranes or titration. DC is calculated using Henry's Law, water temperature, and the steady-state partial pressure of carbon dioxide that develops within the instrument's vertical gas-liquid contacting chamber. Gas-phase partial pressures were determined...
Shear wave velocity, seismic attenuation, and thermal structure of the continental upper mantle
I.M. Artemieva, M. Billien, J.-J. Leveque, Walter D. Mooney
2004, Geophysical Journal International (157) 607-628
Seismic velocity and attenuation anomalies in the mantle are commonly interpreted in terms of temperature variations on the basis of laboratory studies of elastic and anelastic properties of rocks. In order to evaluate the relative contributions of thermal and non-thermal effects on anomalies of attenuation of seismic shear waves, Q−1s, and...
Analysing the 1811-1812 New Madrid earthquakes with recent instrumentally recorded aftershocks
K. Mueller, S. E. Hough, R. Bilham
2004, Nature (429) 284-288
Although dynamic stress changes associated with the passage of seismic waves are thought to trigger earthquakes at great distances, more than 60 per cent of all aftershocks appear to be triggered by static stress changes within two rupture lengths of a mainshock. The observed distribution of aftershocks may thus be...
Interpretation of concentration‐discharge patterns in acid‐neutralizing capacity during storm flow in three small, forested catchments in Shenandoah National Park, Virginia
Karen C. Rice, Jeffrey G. Chanat, George M. Hornberger, James R. Webb
2004, Water Resources Research (40)
Episodic concentration‐discharge (c‐Q) plots are a popular tool for interpreting the hydrochemical response of small, forested catchments. Application of the method involves assuming an underlying conceptual model of runoff processes and comparing observed c‐Q looping patterns with those predicted by the model. We analyzed and interpreted c‐Q plots of acid‐neutralizing capacity (ANC) for 133...
Massive collapse of volcano edifices triggered by hydrothermal pressurization
M.E. Reid
2004, Geology (32) 373-376
Catastrophic collapse of steep volcano flanks threatens lives at stratovolcanoes around the world. Although destabilizing shallow intrusion of magma into the edifice accompanies some collapses (e.g., Mount St. Helens), others have occurred without eruption of juvenile magmatic materials (e.g., Bandai). These latter collapses can be difficult to anticipate. Historic collapses...
Comparison of MODIS and AVHRR 16-day normalized difference vegetation index composite data
Kevin P. Gallo, Lei Ji, Bradley C. Reed, John L. Dwyer, Jeffery C. Eidenshink
2004, Geophysical Research Letters (31)
Normalized difference vegetation index (NDVI) data derived from visible and near-infrared data acquired by the MODIS and AVHRR sensors were compared over the same time periods and a variety of land cover classes within the conterminous USA. The relationship between the AVHRR derived NDVI values and those of future sensors...
Exceptionally fast growth rate of <100-yr-old tufa, Big Soda Lake, Nevada: Implications for using tufa as a peleoclimate proxy
Michael R. Rosen, G.B. Arehart, M.S. Lico
2004, Geology (32) 409-412
Large tufa mounds (>3 m tall, with a basal circumference of 5 m) have been discovered on the margin of Big Soda Lake, Nevada, USA. These tufa mounds are rooted at a maximum of 4 m below the current lake surface and are actively forming from groundwater seepage, which can...
Lateral mixing in the Mississippi River below the confluence with the Ohio River
R. E. Rathbun, C.E. Rostad
2004, Water Resources Research (40)
Lateral dispersion coefficients for two dispersants were determined for three sections of the Mississippi River below the confluence with the Ohio River. The dispersants were the specific conductance and an industrial organic compound (trimethyltriazinetrione). Three models based on the stream tube concept were used, and lateral dispersion coefficients computed from...
Simulation of ventilation efficiency, and pre-closure temperatures in emplacement drifts at Yucca Mountain, Nevada, using Monte Carlo and composite thermal-pulse methods
J.B. Case, D.C. Buesch
2004, Conference Paper, Proceedings of the ASME Heat Transfer/Fluids Engineering Summer Conference 2004, HT/FED 2004
Predictions of waste canister and repository driftwall temperatures as functions of space and time are important to evaluate pre-closure performance of the proposed repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain, Nevada. Variations in the lithostratigraphic features in densely welded and crystallized rocks of the 12.8-million-year-old...
