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Title: Hot Spots and Hot Moments of Nitrogen in a Riparian Corridor

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [2];  [3]
  1. Energy Geosciences Division, Lawrence Berkeley National Laboratory, Berkeley CA USA
  2. Climate and Ecosystem Sciences, Lawrence Berkeley National Laboratory, Berkeley CA USA
  3. Subsurface Insights, LLC, Hanover NH USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1417061
Grant/Contract Number:
SC0009732; AC02-05CH11231
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Water Resources Research
Additional Journal Information:
Related Information: CHORUS Timestamp: 2018-01-16 03:50:55; Journal ID: ISSN 0043-1397
Publisher:
Wiley Blackwell (John Wiley & Sons)
Country of Publication:
United States
Language:
English

Citation Formats

Dwivedi, Dipankar, Arora, Bhavna, Steefel, Carl I., Dafflon, Baptiste, and Versteeg, Roelof. Hot Spots and Hot Moments of Nitrogen in a Riparian Corridor. United States: N. p., 2018. Web. doi:10.1002/2017WR022346.
Dwivedi, Dipankar, Arora, Bhavna, Steefel, Carl I., Dafflon, Baptiste, & Versteeg, Roelof. Hot Spots and Hot Moments of Nitrogen in a Riparian Corridor. United States. doi:10.1002/2017WR022346.
Dwivedi, Dipankar, Arora, Bhavna, Steefel, Carl I., Dafflon, Baptiste, and Versteeg, Roelof. 2018. "Hot Spots and Hot Moments of Nitrogen in a Riparian Corridor". United States. doi:10.1002/2017WR022346.
@article{osti_1417061,
title = {Hot Spots and Hot Moments of Nitrogen in a Riparian Corridor},
author = {Dwivedi, Dipankar and Arora, Bhavna and Steefel, Carl I. and Dafflon, Baptiste and Versteeg, Roelof},
abstractNote = {},
doi = {10.1002/2017WR022346},
journal = {Water Resources Research},
number = ,
volume = ,
place = {United States},
year = 2018,
month = 1
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on January 16, 2019
Publisher's Accepted Manuscript

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  • Primary consumers play important roles in the cycling of nutrients in headwater streams, storing assimilated nutrients in growing tissue and recycling them through excretion. Though environmental conditions in most headwater streams and their surrounding terrestrial ecosystems vary considerably over the course of a year, relatively little is known about the effects of seasonality on consumer nutrient recycling these streams. Here, we measured nitrogen accumulated through growth and excreted by the grazing snail Elimia clavaeformis (Pleuroceridae) over the course of 12 months in Walker Branch, identifying close connections between in-stream nitrogen processing and seasonal changes in the surrounding forest.
  • We aim to understand the scale-dependent evolution of uranium bioreduction during a field experiment at a former uranium mill site near Rifle, Colorado. Acetate was injected to stimulate Fe-reducing bacteria (FeRB) and to immobilize aqueous U(VI) to insoluble U(IV). Bicarbonate was coinjected in half of the domain to mobilize sorbed U(VI). We used reactive transport modeling to integrate hydraulic and geochemical data and to quantify rates at the grid block (0.25 m) and experimental field scale (tens of meters). Although local rates varied by orders of magnitude in conjunction with biostimulation fronts propagating downstream, field-scale rates were dominated by thosemore » orders of magnitude higher rates at a few selected hot spots where Fe(III), U(VI), and FeRB were at their maxima in the vicinity of the injection wells. At particular locations, the hot moments with maximum rates negatively corresponded to their distance from the injection wells. Although bicarbonate injection enhanced local rates near the injection wells by a maximum of 39.4%, its effect at the field scale was limited to a maximum of 10.0%. We propose a rate-versus-measurement-length relationship (log R' = -0.63« less
  • In this paper we report the results of experiments that compare the x-ray emission from a laser spot in a radiation-filled hohlraum to that from a similar laser spot on a simple disk target. The studies were done using the Nova laser facility [J. D. Lindl, Phys. Plasmas {bold 2}, 3933 (1995)] in its 0.35 {mu}m wavelength, 1 ns square pulse configuration. Focal spot intensities were 2{endash}3.5{times}10{sup 15} W/cm{sup 2}. X-ray images measured x-ray conversion in a hohlraum and from an isolated disk simultaneously. A laser spot inside a hohlraum emitted more x rays, after subtracting the background emission frommore » the hohlraum walls, than a spot on a disk. Numerical models suggest the enhanced spot emission inside the hohlraum is due to an increase in lateral transport relative to the disk. Filamentation in the hohlraum will also increase the spot size. The models agree fairly well with the results on spot spreading but do not explain the overall increase in conversion efficiency. {copyright} {ital 1997 American Institute of Physics.}« less