東華大學圖書館 |

The Distributions and Geochemistry of Iodine and Copper in the Pacific Ocean.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	The Distributions and Geochemistry of Iodine and Copper in the Pacific Ocean./
作者:	Moriyasu, Rintaro.
面頁冊數:	1 online resource (210 pages)
附註:	Source: Dissertations Abstracts International, Volume: 84-03, Section: B.
Contained By:	Dissertations Abstracts International84-03B.
標題:	Chemical oceanography. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29214695click for full text (PQDT)
ISBN:	9798841740643

The Distributions and Geochemistry of Iodine and Copper in the Pacific Ocean.
Moriyasu, Rintaro.

The Distributions and Geochemistry of Iodine and Copper in the Pacific Ocean. - 1 online resource (210 pages)

Source: Dissertations Abstracts International, Volume: 84-03, Section: B.

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

Includes bibliographical references

The distributions of iodine and copper speciation were measured along three different cruises, within the (mainly North) Pacific Ocean, one of which was a GEOTRACES cruise. GEOTRACES is an international collaborative effort to elucidate the biogeochemical cycling of various trace elements and isotopes (TEIs). Many of these elements are considered nutrients, and their distributions and cycling have biological impacts, especially on phytoplankton. Marine iodine is mostly found in its two inorganic forms: iodate and iodide. The former is found throughout most of the oxygenated ocean while the latter was thought to be enriched in the surface ocean and in anoxic regions, referred to as Oxygen Deficient Zones (ODZs). In this thesis, high iodide concentrations were found in these ODZs, which cannot be explained by the in situ reduction of available iodate, and likely to originate as a "plume" from the reducing shelf margins off of the Mexican coast. These high iodide values were referred to as "excess iodine" and found to persist even at the edges of these ODZs, likely to do with the slow abiotic oxidation rate of iodide by oxygen and other terminal electron acceptors (chapter 1). These measurements were repeated in the GEOTRACES GP15 which left from the shelf of Alaska and transected to Tahiti. Although high rates of sulfate reduction have been predicted to occur off of Alaska, no large plume of highly concentrated iodide was observed along this cruise. Instead, this cruise offered the opportunity to find that: previous iodide measurements made within the South Pacific are likely erroneous, and the rate of surface iodide oxidation using a non-linear fit with complementary beryllium measurements (chapter 3). Copper, a unique element, is considered a nutrient at low concentrations and a toxin higher concentration. It is also considered a "hybrid" element for its depth profiles which exhibit behaviors of both "nutrient-like" and "scavenged" distributions; this behavior is exhibited in the form of a linear depth profile which increase from surface to benthic waters. Most (≥ 99%) of the dissolved copper pool is bound by organic molecules and considered biologically inert, and many workers study the compounds that bind the metal through electrochemical methods. One hypothesis, for the linear depth distribution, is that some of these compounds bind to copper so tightly that it prevents scavenging by sinking particulate matter. This tightly bound fraction of dissolved copper is referred to as "inert copper". This work explored this hypothesis and required the creation of a novel method to physically separate (via a process of liquid-liquid extraction)dissolved copper into two pools: labile and inert (chapter 2). The method was then applied to, the previously mentioned transect, GEOTRACES GP15 (chapter 4). The data reveal that 60-90% of marine copper is rendered chemically inert throughout the ocean. Labile copper, on the other hand, exhibits a profile similar to other scavenged elements at most locations: higher concentrations at surface waters with a sharp decline with depth due to scavenging by particles. There appears to also be a benthic source of labile copper, as well, which is likely due to the destruction of the binding capacity of the particulate with diagenesis. Our findings conclude that copper complexation by, ligands and organic materials, are not all reversible, as suggested by our current paradigm.

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

Mode of access: World Wide Web

ISBN: 9798841740643Subjects--Topical Terms:

516760
Chemical oceanography.
Subjects--Index Terms:

GeochemistryIndex Terms--Genre/Form:

542853
Electronic books.

The Distributions and Geochemistry of Iodine and Copper in the Pacific Ocean.
LDR:04769nmm a2200373K 4500 001 2357563
005 20230725053515.5
006 m o d
007 cr mn ---uuuuu
008 241011s2022 xx obm 000 0 eng d
020 $a 9798841740643
035 $a (MiAaPQ)AAI29214695
035 $a AAI29214695
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Moriyasu, Rintaro. $3 3698094
245 1 4 $a The Distributions and Geochemistry of Iodine and Copper in the Pacific Ocean.
264 0 $c 2022
300 $a 1 online resource (210 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: 84-03, Section: B.
500 $a Advisor: Moffett, James.
502 $a Thesis (Ph.D.)--University of Southern California, 2022.
504 $a Includes bibliographical references
520 $a The distributions of iodine and copper speciation were measured along three different cruises, within the (mainly North) Pacific Ocean, one of which was a GEOTRACES cruise. GEOTRACES is an international collaborative effort to elucidate the biogeochemical cycling of various trace elements and isotopes (TEIs). Many of these elements are considered nutrients, and their distributions and cycling have biological impacts, especially on phytoplankton. Marine iodine is mostly found in its two inorganic forms: iodate and iodide. The former is found throughout most of the oxygenated ocean while the latter was thought to be enriched in the surface ocean and in anoxic regions, referred to as Oxygen Deficient Zones (ODZs). In this thesis, high iodide concentrations were found in these ODZs, which cannot be explained by the in situ reduction of available iodate, and likely to originate as a "plume" from the reducing shelf margins off of the Mexican coast. These high iodide values were referred to as "excess iodine" and found to persist even at the edges of these ODZs, likely to do with the slow abiotic oxidation rate of iodide by oxygen and other terminal electron acceptors (chapter 1). These measurements were repeated in the GEOTRACES GP15 which left from the shelf of Alaska and transected to Tahiti. Although high rates of sulfate reduction have been predicted to occur off of Alaska, no large plume of highly concentrated iodide was observed along this cruise. Instead, this cruise offered the opportunity to find that: previous iodide measurements made within the South Pacific are likely erroneous, and the rate of surface iodide oxidation using a non-linear fit with complementary beryllium measurements (chapter 3). Copper, a unique element, is considered a nutrient at low concentrations and a toxin higher concentration. It is also considered a "hybrid" element for its depth profiles which exhibit behaviors of both "nutrient-like" and "scavenged" distributions; this behavior is exhibited in the form of a linear depth profile which increase from surface to benthic waters. Most (≥ 99%) of the dissolved copper pool is bound by organic molecules and considered biologically inert, and many workers study the compounds that bind the metal through electrochemical methods. One hypothesis, for the linear depth distribution, is that some of these compounds bind to copper so tightly that it prevents scavenging by sinking particulate matter. This tightly bound fraction of dissolved copper is referred to as "inert copper". This work explored this hypothesis and required the creation of a novel method to physically separate (via a process of liquid-liquid extraction)dissolved copper into two pools: labile and inert (chapter 2). The method was then applied to, the previously mentioned transect, GEOTRACES GP15 (chapter 4). The data reveal that 60-90% of marine copper is rendered chemically inert throughout the ocean. Labile copper, on the other hand, exhibits a profile similar to other scavenged elements at most locations: higher concentrations at surface waters with a sharp decline with depth due to scavenging by particles. There appears to also be a benthic source of labile copper, as well, which is likely due to the destruction of the binding capacity of the particulate with diagenesis. Our findings conclude that copper complexation by, ligands and organic materials, are not all reversible, as suggested by our current paradigm.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Chemical oceanography. $3 516760
650 4 $a Geochemistry. $3 539092
653 $a Geochemistry
653 $a Iodine
653 $a Copper
653 $a Pacific Ocean
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0403
690 $a 0996
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a University of Southern California. $b Ocean Sciences. $3 3698095
773 0 $t Dissertations Abstracts International $g 84-03B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29214695 $z click for full text (PQDT)