Trace metal fluxes to the ocean: The importance of high‐standing oceanic islands

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94592/1/grl16149.pd

Patterns of Ca/Sr and 87Sr/86Sr variation before and after a whole watershed CaSiO3 addition at the Hubbard Brook Experimental Forest, USA

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155691/1/Nezat_et_al_2010_Patterns_of_Ca-Sr.pd

A sequential extraction to determine the distribution of apatite in granitoid soil mineral pools with application to weathering at the Hubbard Brook Experimental Forest, NH, USA

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155866/1/Nezat_et_al_2007_Sequential_extraction.pd

Fossil fuel burning in Taylor Valley, southern Victoria Land, Antarctica: Estimating the role of scientific activities on carbon and nitrogen reservoirs and fluxes

Particulate organic and elemental carbon and nitrogen as well as NO(x) fluxes from scientific activities have been computed for Taylor Valley, Antarctica (≃78°S). These authropogenic fluxes have been compared to both the \u27natural\u27 fluxes and landscape reservoirs as determined from Long-Term Ecological Research (LTER) investigations in the valley. The anthropogenic, nongaseous carbon fluxes are minor compared to the natural fluxes, while the anthropogenic NO(x) flux may be potentially important over decadal time scales

Mineral Sources of Calcium and Phosphorus in Soils of the Northeastern United States

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152491/1/saj2sssaj20070344.pd

Nitrogen budget of the Mobile-Alabama River system watershed.

Abstract We have determined the nitrogen mass balance for the Mobile–Alabama River System (MARS) for two years of different hydrologic regimes (i.e. low flow vs.high flow). The maximum riverine export of N from the watershed is only 7%, suggesting relatively high retention and/or losses of N by denitrification within the watershed. Previous investigations of other watersheds within the USA demonstrate export percentages of c. 20–25%. Our calculations indicate that during a high flow year such as 1990, c. 13% of the new N introduced to the watershed annually is lost within the riverine system either through diatom uptake or denitrification. Another 4% is lost to the groundwater while 25–38% is sequestered by the terrestrial biomass (i.e. crop production and forest growth). Thus, as much as 51% of the N input to the landscape in the MARS is unaccounted for. We believe the location of this ‘missing’ N is probably within the soil, or the N has been lost through denitrification within the terrestrial ecosystem. The relatively low N yield from the MARS suggests that the watershed is not as saturated with respect to N as are many other U.S. drainages

Strontium Isotopic Signatures of the Streams and Lakes of Taylor Valley, Southern Victoria Land, Antarctica: ChemicalWeathering in a Polar Climate

We have collected and analyzed a series of water samples from three closed-basin lakes (Lakes Bonney, Fryxell, and Hoare) in Taylor Valley, Antarctica, and the streams that flow into them. In all three lakes, the hypolimnetic waters have different 87Sr/86Sr ratios than the surface waters, with the deep water of Lakes Fryxell and Hoare being less radiogenic than the surface waters. The opposite occurs in Lake Bonney. The Lake Fryxell isotopic ratios are lower than modern-day ocean water and most of the whole-rock ratios of the surrounding geologic materials. A conceivable source of Sr to the system could be either the Cenozoic volcanic rocks that make up a small portion of the till deposited in the valley during the Last Glacial Maximum or from marble derived from the local basement rocks. The more radiogenic ratios from Lake Bonney originate from ancient salt deposits that flow into the lake from Taylor Glacier and the weathering of minerals with more radiogenic Sr isotopic ratios within the tills. The Sr isotopic data from the streams and lakes of Taylor Valley strongly support the notion documented by previous investigators that chemical weathering has been, and is currently, a major process in determining the overall aquatic chemistry of these lakes in this polar desert environment

New insight into calcium depletion in northeastern forests

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155857/1/Yanai_et_al_2005_New_insights.pd

Influence of landscape position and vegetation on long-term weathering rates at the Hubbard Brook Experimental Forest, New Hampshire, USA

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155853/1/Nezat_et_al_2004_Influence_of_landscape.pd