東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

FindBook

Google Book

Amazon

博客來

Development of Numerical Models to Predict Cycling of Mercury and Salt in Freshwater.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Development of Numerical Models to Predict Cycling of Mercury and Salt in Freshwater./
作者:	Helmrich, Stefanie.
面頁冊數:	1 online resource (91 pages)
附註:	Source: Dissertations Abstracts International, Volume: 84-05, Section: B.
Contained By:	Dissertations Abstracts International84-05B.
標題:	Environmental science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29326691click for full text (PQDT)
ISBN:	9798357572165

Development of Numerical Models to Predict Cycling of Mercury and Salt in Freshwater.
Helmrich, Stefanie.

Development of Numerical Models to Predict Cycling of Mercury and Salt in Freshwater. - 1 online resource (91 pages)

Source: Dissertations Abstracts International, Volume: 84-05, Section: B.

Thesis (Ph.D.)--University of California, Merced, 2022.

Includes bibliographical references

This dissertation focuses on understanding and quantifying how environmental conditions affect the fate of salinity and mercury in freshwater. Salinity and mercury concentrations are increasing due to anthropogenic activity and threaten ecosystem services of water bodies. Management is important to prevent further degradation. To reconcile management of multiple water quality parameters with ecosystem services, an improved basic knowledge and advanced tools are important. It is still difficult to identify main drivers for elevated salinity at a specific site and there are gaps in our basic understanding of mercury cycling. Therefore, this research focused on development and application of numerical models to improve our understanding of salinity and mercury cycling and to provide tools to plan management measures. The aim of the first chapter was to continue development of a module for seasonally managed wetlands as part of a real-time forecasting tool for salinity in the San Joaquin River watershed. Revising water sources, inflow time series, and model variables that determine the timing of outflow improved model performance by better representing the extensive reuse and recirculation within wetlands. Adequate simulation of conservative water quality parameters such as salinity is a pre-requisite to simulate non-conservative parameters such as mercury. The second chapter focused on critically reviewing published kinetic rate constants for mercury methylation and demethylation including application to a reaction-transport model. Mercury exists in multiple chemical forms and monomethylmercury (MeHg) is one of the most toxic forms. Two important variables that determine MeHg concentrations are the rate of MeHg production and degradation. The critical review informs selection of rate constants from literature and provides a tool to assess rate constants. Experimental conditions and mathematical assumptions were found to cause uncertainty and limit comparability. The aim of the third chapter was to apply a kinetic-thermodynamic model to field data to evaluate how environmental conditions affect MeHg production. The chapter shows how field data can be used to constrain model parameters. A novel rate formulation was developed to simulate precipitation of Hg minerals depending on concentrations of sulfur and organic matter. The addition of the rate improved simulated MeHg under a range of sulfide concentrations. Overall, numerical models proved suitable to identify knowledge gaps and improve basic understanding for both salinity and mercury in freshwater.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798357572165Subjects--Topical Terms:

677245
Environmental science.
Subjects--Index Terms:

Numerical modelsIndex Terms--Genre/Form:

542853
Electronic books.

Development of Numerical Models to Predict Cycling of Mercury and Salt in Freshwater.
LDR:04028nmm a2200409K 4500 001 2356257
005 20230612072250.5
006 m o d
007 cr mn ---uuuuu
008 241011s2022 xx obm 000 0 eng d
020 $a 9798357572165
035 $a (MiAaPQ)AAI29326691
035 $a AAI29326691
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Helmrich, Stefanie. $3 3696736
245 1 0 $a Development of Numerical Models to Predict Cycling of Mercury and Salt in Freshwater.
264 0 $c 2022
300 $a 1 online resource (91 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 84-05, Section: B.
500 $a Includes supplementary digital materials.
500 $a Advisor: O'Day, Peggy A.
502 $a Thesis (Ph.D.)--University of California, Merced, 2022.
504 $a Includes bibliographical references
520 $a This dissertation focuses on understanding and quantifying how environmental conditions affect the fate of salinity and mercury in freshwater. Salinity and mercury concentrations are increasing due to anthropogenic activity and threaten ecosystem services of water bodies. Management is important to prevent further degradation. To reconcile management of multiple water quality parameters with ecosystem services, an improved basic knowledge and advanced tools are important. It is still difficult to identify main drivers for elevated salinity at a specific site and there are gaps in our basic understanding of mercury cycling. Therefore, this research focused on development and application of numerical models to improve our understanding of salinity and mercury cycling and to provide tools to plan management measures. The aim of the first chapter was to continue development of a module for seasonally managed wetlands as part of a real-time forecasting tool for salinity in the San Joaquin River watershed. Revising water sources, inflow time series, and model variables that determine the timing of outflow improved model performance by better representing the extensive reuse and recirculation within wetlands. Adequate simulation of conservative water quality parameters such as salinity is a pre-requisite to simulate non-conservative parameters such as mercury. The second chapter focused on critically reviewing published kinetic rate constants for mercury methylation and demethylation including application to a reaction-transport model. Mercury exists in multiple chemical forms and monomethylmercury (MeHg) is one of the most toxic forms. Two important variables that determine MeHg concentrations are the rate of MeHg production and degradation. The critical review informs selection of rate constants from literature and provides a tool to assess rate constants. Experimental conditions and mathematical assumptions were found to cause uncertainty and limit comparability. The aim of the third chapter was to apply a kinetic-thermodynamic model to field data to evaluate how environmental conditions affect MeHg production. The chapter shows how field data can be used to constrain model parameters. A novel rate formulation was developed to simulate precipitation of Hg minerals depending on concentrations of sulfur and organic matter. The addition of the rate improved simulated MeHg under a range of sulfide concentrations. Overall, numerical models proved suitable to identify knowledge gaps and improve basic understanding for both salinity and mercury in freshwater.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Environmental science. $3 677245
650 4 $a Geochemistry. $3 539092
650 4 $a Water resources management. $3 794747
650 4 $a Applied mathematics. $3 2122814
653 $a Numerical models
653 $a Mercury content
653 $a Salt content
653 $a Freshwater cyling
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0768
690 $a 0996
690 $a 0595
690 $a 0364
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a University of California, Merced. $b Environmental Systems. $3 2103051
773 0 $t Dissertations Abstracts International $g 84-05B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29326691 $z click for full text (PQDT)