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Constraining Sources of Archaeal Tetra-Ether Lipids in Marine Sediments Using Compound-Specific Isotope Analysis
Constraining Sources of Archaeal Tetra-Ether Lipids in Marine Sediments Using Compound-Specific Isotope Analysis
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20250211152832
- ISBN
- 9798346532774
- DDC
- 551
- 서명/저자
- Constraining Sources of Archaeal Tetra-Ether Lipids in Marine Sediments Using Compound-Specific Isotope Analysis
- 발행사항
- [Sl] : Harvard University, 2024
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2024
- 형태사항
- 111 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 86-05, Section: B.
- 주기사항
- Advisor: Pearson, Ann.
- 학위논문주기
- Thesis (Ph.D.)--Harvard University, 2024.
- 초록/해제
- 요약Archaeal isoprenoid glycerol dialkyl glycerol tetraether lipids (iGDGTs) are commonly used tools in paleooceanography for reconstructing past surface temperatures and carbon cycle dynamics. However, uncertainties persist regarding the origins of iGDGTs in marine sediments, requiring a deeper understanding of their diverse sources. The TEX86 sea-surface temperature proxy, based on the ratio of cyclized iGDGTs, assumes that majority of sedimentary iGDGTs originate from a single, planktonic archaeal representative. Yet, the influence of allochthonous input from benthic in-situ and terrestrial sources is unresolved, potentially calling into question the fidelity of iGDGT-based proxies. This thesis aims to address these uncertainties by constraining sources of sedimentary iGDGTs through compound-specific carbon and hydrogen isotope analysis. We develop a dual-isotopic framework to determine iGDGT source apportionment in methane-impacted systems, characterize the δ13C and δ2H isotopic signatures and lipid profiles of potential archaeal sources, and evaluate the impact of heterogenous inputs on the reliability and application of iGDGT-based proxies.In Chapter 2, we conducted analytical tests to evaluate the effects of high-performance liquid chromatography (HPLC) on the carbon isotopic (δ13C) analysis of iGDGTs. Our findings show that normal phase HPLC can cause significant isotopic fractionation, exceeding analytical thresholds, emphasizing the need for precise and complete peak collection during normal phase HPLC for accurate isotope ratio quantification. In Chapter 3, we measured the δ13C values and relative lipid abundances of iGDGTs from three cold-seep locations along Cascadia Margin, using a Bayesian mixing model to robustly characterize the δ13C signatures, lipid profiles and relative contributions to the marine sediment of three potential archaeal endmembers. Our results indicate that the cold seep systems in this region can be described as a binary mixing system between planktonic and benthic-methane cycling archaeal groups, with minimal contribution from benthic non-methane-cycling archaea. Finally, in Chapter 4, we introduce a novel dual-isotope approach, combining δ2H and δ13C analyses of biphytanes derivatives and parent iGDGTs, respectively, to quantitatively distinguish lipid inputs to marine systems. Our findings indicate that planktonic and benthic methane-cycling archaea both yield highly 2H-fractionated lipids, providing an interpretative basis for applying dual isotopic analysis to disentangle iGDGT sources in marine systems.
- 일반주제명
- Biogeochemistry
- 일반주제명
- Geochemistry
- 일반주제명
- Sedimentary geology
- 일반주제명
- Marine geology
- 일반주제명
- Analytical chemistry
- 키워드
- Isotopes
- 키워드
- Lipid biomarkers
- 키워드
- Marine sediments
- 기타저자
- Harvard University Earth and Planetary Sciences
- 기본자료저록
- Dissertations Abstracts International. 86-05B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■020 ▼a9798346532774
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■1001 ▼aKeller, Katherine.▼0(orcid)0000-0001-6915-5455
■24510▼aConstraining Sources of Archaeal Tetra-Ether Lipids in Marine Sediments Using Compound-Specific Isotope Analysis
■260 ▼a[Sl]▼bHarvard University▼c2024
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2024
■300 ▼a111 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 86-05, Section: B.
■500 ▼aAdvisor: Pearson, Ann.
■5021 ▼aThesis (Ph.D.)--Harvard University, 2024.
■520 ▼aArchaeal isoprenoid glycerol dialkyl glycerol tetraether lipids (iGDGTs) are commonly used tools in paleooceanography for reconstructing past surface temperatures and carbon cycle dynamics. However, uncertainties persist regarding the origins of iGDGTs in marine sediments, requiring a deeper understanding of their diverse sources. The TEX86 sea-surface temperature proxy, based on the ratio of cyclized iGDGTs, assumes that majority of sedimentary iGDGTs originate from a single, planktonic archaeal representative. Yet, the influence of allochthonous input from benthic in-situ and terrestrial sources is unresolved, potentially calling into question the fidelity of iGDGT-based proxies. This thesis aims to address these uncertainties by constraining sources of sedimentary iGDGTs through compound-specific carbon and hydrogen isotope analysis. We develop a dual-isotopic framework to determine iGDGT source apportionment in methane-impacted systems, characterize the δ13C and δ2H isotopic signatures and lipid profiles of potential archaeal sources, and evaluate the impact of heterogenous inputs on the reliability and application of iGDGT-based proxies.In Chapter 2, we conducted analytical tests to evaluate the effects of high-performance liquid chromatography (HPLC) on the carbon isotopic (δ13C) analysis of iGDGTs. Our findings show that normal phase HPLC can cause significant isotopic fractionation, exceeding analytical thresholds, emphasizing the need for precise and complete peak collection during normal phase HPLC for accurate isotope ratio quantification. In Chapter 3, we measured the δ13C values and relative lipid abundances of iGDGTs from three cold-seep locations along Cascadia Margin, using a Bayesian mixing model to robustly characterize the δ13C signatures, lipid profiles and relative contributions to the marine sediment of three potential archaeal endmembers. Our results indicate that the cold seep systems in this region can be described as a binary mixing system between planktonic and benthic-methane cycling archaeal groups, with minimal contribution from benthic non-methane-cycling archaea. Finally, in Chapter 4, we introduce a novel dual-isotope approach, combining δ2H and δ13C analyses of biphytanes derivatives and parent iGDGTs, respectively, to quantitatively distinguish lipid inputs to marine systems. Our findings indicate that planktonic and benthic methane-cycling archaea both yield highly 2H-fractionated lipids, providing an interpretative basis for applying dual isotopic analysis to disentangle iGDGT sources in marine systems.
■590 ▼aSchool code: 0084.
■650 4▼aBiogeochemistry
■650 4▼aGeochemistry
■650 4▼aSedimentary geology
■650 4▼aMarine geology
■650 4▼aAnalytical chemistry
■653 ▼aArchaeal tetra-ether lipids
■653 ▼aIsotopes
■653 ▼aLipid biomarkers
■653 ▼aMarine sediments
■653 ▼aHigh-performance liquid chromatography
■690 ▼a0425
■690 ▼a0996
■690 ▼a0486
■690 ▼a0556
■690 ▼a0594
■71020▼aHarvard University▼bEarth and Planetary Sciences.
■7730 ▼tDissertations Abstracts International▼g86-05B.
■790 ▼a0084
■791 ▼aPh.D.
■792 ▼a2024
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17164102▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
