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The processing of mercury in foreste...

Rea, Anne Winona.

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The processing of mercury in forested ecosystems.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	The processing of mercury in forested ecosystems./
作者:	Rea, Anne Winona.
面頁冊數:	126 p.
附註:	Chair: Gerald J. Keeler.
Contained By:	Dissertation Abstracts International59-07B.
標題:	Biogeochemistry. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9840633
ISBN:	0591945460

The processing of mercury in forested ecosystems.
Rea, Anne Winona.

The processing of mercury in forested ecosystems. - 126 p.

Chair: Gerald J. Keeler.

Thesis (Ph.D.)--University of Michigan, 1998.

7% was accounted for by total throughfall $(6.7\pm0.2\ \muThe measured total Hg deposition to the forest floor of a northern mixed-hardwood forest in litterfall and throughfall was 18.1 $\pm$ 3.0 $\mu

ISBN: 0591945460Subjects--Topical Terms:

545717
Biogeochemistry.

The processing of mercury in forested ecosystems.
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020 $a 0591945460
035 $a (UnM)AAI9840633
035 $a AAI9840633
040 $a UnM $c UnM
100 1 $a Rea, Anne Winona. $3 1256908
245 1 0 $a The processing of mercury in forested ecosystems.
300 $a 126 p.
500 $a Chair: Gerald J. Keeler.
500 $a Source: Dissertation Abstracts International, Volume: 59-07, Section: B, page: 3319.
502 $a Thesis (Ph.D.)--University of Michigan, 1998.
520 $a The measured total Hg deposition to the forest floor of a northern mixed-hardwood forest in litterfall and throughfall was 18.1 $\pm$ 3.0 $\mu $g m$\sp{-2}$ during June to November, 1996. Litterfall accounted for $\sim $6 3% of the Hg deposition $(11.4\pm2.8\ \mu $g m$\sp{-2})$ and $\sim $3 7% was accounted for by total throughfall $(6.7\pm0.2\ \mu $g m$\sp{-2}$; 10% from wash-off of dry deposition in net throughfall, and 27% from incoming precipitation). To identify the source(s) of Hg in litterfall and throughfall, samples were collected from ecosystem components (live foliage, litterfall, throughfall, precipitation, ambient air, and soil).
520 $a Concentrations of Hg in foliage increased steadily from $3 .3\pm1.1$ ng g$\sp{-1}$ at bud break to $3 2.5\pm8.1$ ng g$\sp{-1}$ in litterfall in all tree species sampled. Based on foliar Hg measurements, leaves needed to accumulate, on average, 25% (16-34%) of the available atmospheric Hg$\sp0.$ Estimates of Hg uptake from soil water transpiration could only account for 3-14% of the Hg in litterfall, and uptake of Hg from mineral soil was negligible. To determine if any of the Hg accumulating in leaves would leach out over time, leaf washing experiments demonstrated that wash-off of Hg followed first order kinetics $(k=2.2\times10\sp{-2}\pm1\times10\sp{-3}$ min$\sp{-1}$; R$\sp2$ = 0.92) and that foliar leaching of Hg did not occur. Dry deposition fluxes measured from both live foliage $(0.23\pm0.25$ ng $\rm m\sp{-2}\ hr\sp{-1})$ and surrogate Teflon surfaces $(0.19\pm0.25$ ng $\rm m\sp{-2}\ hr\sp{-1})$ were similar, indicating that the Hg removed by washing was due to wash-off of dry deposited Hg. Measurements of total throughfall and precipitation also showed that wash-off of dry deposition was the source of Hg in net throughfall.
520 $a Based on the processing mechanisms identified in this research, the Hg deposited to the forest floor in litterfall and throughfall represent atmospheric inputs of Hg into forested ecosystems. Over 70% $\rm(13.2\pm2.9\ \mu g\ m\sp{-2})$ of the Hg entering this forested ecosystem was due to dry deposition of atmospheric Hg. The importance of the Hg released in litterfall and throughfall to aquatic ecosystems may be a frequently overlooked source of Hg in fish tissue.
590 $a School code: 0127.
650 4 $a Biogeochemistry. $3 545717
650 4 $a Biology, Ecology. $3 1017726
650 4 $a Biology, Plant Physiology. $3 1017865
650 4 $a Environmental Sciences. $3 676987
650 4 $a Physics, Atmospheric Science. $3 1019431
690 $a 0329
690 $a 0425
690 $a 0608
690 $a 0768
690 $a 0817
710 2 0 $a University of Michigan. $3 777416
773 0 $t Dissertation Abstracts International $g 59-07B.
790 $a 0127
790 1 0 $a Keeler, Gerald J., $e advisor
791 $a Ph.D.
792 $a 1998
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9840633