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Mercury and methylmercury in Spring ...

Hines, Neal Albert,

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Mercury and methylmercury in Spring Lake, Minnesota: A mass balance approach comparing redox transformations, methylmercury photodegradation, sediment loading, and watershed processes /

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Mercury and methylmercury in Spring Lake, Minnesota: A mass balance approach comparing redox transformations, methylmercury photodegradation, sediment loading, and watershed processes // Neal Albert Hines.
作者:	Hines, Neal Albert,
面頁冊數:	1 electronic resource (128 pages)
附註:	Source: Dissertations Abstracts International, Volume: 66-11, Section: B.
Contained By:	Dissertations Abstracts International66-11B.
標題:	Biogeochemistry. -
電子資源:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3158450
ISBN:	9780496909759

Mercury and methylmercury in Spring Lake, Minnesota: A mass balance approach comparing redox transformations, methylmercury photodegradation, sediment loading, and watershed processes /
Hines, Neal Albert,

Mercury and methylmercury in Spring Lake, Minnesota: A mass balance approach comparing redox transformations, methylmercury photodegradation, sediment loading, and watershed processes /Neal Albert Hines. - 1 electronic resource (128 pages)

Source: Dissertations Abstracts International, Volume: 66-11, Section: B.

Processes of total mercury (HgT) and methylmercury (MeHg) cycling are described for Spring Lake, a small bog lake in northern Minnesota, within the Marcell Experimental Forest north of Grand Rapids. I quantified redox transformations, photodegradation of MeHg, internal and external loading, and modeled Hg cycling using the software Stella®. Measurements on lake sediment cores and sediment porewater allowed for separate treatment of lake and sediment environments. Recent sediment accumulation of Hg T was 21.4 μg m−2 yr−1 (1990-2000), two orders of magnitude greater than accumulation of MeHg (0.20 μg m−2 yr−1). Porewater profiles showed a small diffusive flux of MeHg from sediment to water (5 ng m−2 mo−1). The percent of HgT present as MeHg was highest in the water column above the sediment (10%) and decreased with sediment depth in both the solid and porewater phases. Losses of HgT from evasion of Hg0 (lake to atmosphere) during the daytime in 2001 and 2002 averaged 1.1 ng m −2 h−1 and were 21% of the output of Hg T from Spring Lake. The loss from evasion of Hg0, 261 mg (March-November), was much smaller than the HgT loss from burial (859 mg). Atmospheric deposition is the main input of HgT to the lake, but MeHg is supplied by a combination of atmospheric, near-shore wetland, sediment porewater, and biotic sources (methylation). Bog and upland runoff were minor components to the total inputs for both HgT and MeHg. For MeHg, wet deposition is only 8.2% of the total MeHg input, and other external inputs (runoff, porewater) provide an additional 6.8%, indicating that internal production of MeHg is occurring. The residence times of MeHg and HgT in the lake were 47 and 60 d, respectively, during the open-water season. For Hg0, the rate of photoreduction (producing Hg0) was twice that of photooxidation (loss of Hg0) and the residence time in the photic zone was short (hours). Although in-lake methylation provided the majority of inputs of MeHg to the lake (85%; determined by mass balance), the combination of photodegradation and degradation on seston and sediment result in net demethylion at Spring Lake.

English

ISBN: 9780496909759Subjects--Topical Terms:

545717
Biogeochemistry.
Subjects--Index Terms:

Mercury

Mercury and methylmercury in Spring Lake, Minnesota: A mass balance approach comparing redox transformations, methylmercury photodegradation, sediment loading, and watershed processes /
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300 $a 1 electronic resource (128 pages)
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500 $a Source: Dissertations Abstracts International, Volume: 66-11, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisors: Brezonik, Patrick L.
502 $b Ph.D. $c University of Minnesota $d 2004.
520 $a Processes of total mercury (HgT) and methylmercury (MeHg) cycling are described for Spring Lake, a small bog lake in northern Minnesota, within the Marcell Experimental Forest north of Grand Rapids. I quantified redox transformations, photodegradation of MeHg, internal and external loading, and modeled Hg cycling using the software Stella®. Measurements on lake sediment cores and sediment porewater allowed for separate treatment of lake and sediment environments. Recent sediment accumulation of Hg T was 21.4 μg m−2 yr−1 (1990-2000), two orders of magnitude greater than accumulation of MeHg (0.20 μg m−2 yr−1). Porewater profiles showed a small diffusive flux of MeHg from sediment to water (5 ng m−2 mo−1). The percent of HgT present as MeHg was highest in the water column above the sediment (10%) and decreased with sediment depth in both the solid and porewater phases. Losses of HgT from evasion of Hg0 (lake to atmosphere) during the daytime in 2001 and 2002 averaged 1.1 ng m −2 h−1 and were 21% of the output of Hg T from Spring Lake. The loss from evasion of Hg0, 261 mg (March-November), was much smaller than the HgT loss from burial (859 mg). Atmospheric deposition is the main input of HgT to the lake, but MeHg is supplied by a combination of atmospheric, near-shore wetland, sediment porewater, and biotic sources (methylation). Bog and upland runoff were minor components to the total inputs for both HgT and MeHg. For MeHg, wet deposition is only 8.2% of the total MeHg input, and other external inputs (runoff, porewater) provide an additional 6.8%, indicating that internal production of MeHg is occurring. The residence times of MeHg and HgT in the lake were 47 and 60 d, respectively, during the open-water season. For Hg0, the rate of photoreduction (producing Hg0) was twice that of photooxidation (loss of Hg0) and the residence time in the photic zone was short (hours). Although in-lake methylation provided the majority of inputs of MeHg to the lake (85%; determined by mass balance), the combination of photodegradation and degradation on seston and sediment result in net demethylion at Spring Lake.
546 $a English
590 $a School code: 0130
650 4 $a Biogeochemistry. $3 545717
650 4 $a Environmental science. $3 677245
650 4 $a Environmental engineering. $3 548583
650 4 $a Freshwater ecology. $3 600668
650 4 $a Limnology. $3 545788
653 $a Mercury
653 $a Methylmercury
653 $a Minnesota
653 $a Photodegradation
653 $a Sediment loading
653 $a Spring Lake
653 $a Watershed
690 $a 0425
690 $a 0768
690 $a 0775
690 $a 0793
710 2 $a University of Minnesota. $e degree granting institution. $3 3765849
720 1 $a Brezonik, Patrick L. $e degree supervisor.
773 0 $t Dissertations Abstracts International $g 66-11B.
790 $a 0130
791 $a Ph.D.
792 $a 2004
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3158450