Intact Polar brGDGTs in Arctic Lake Catchments: Implications for Lipid Sources and Paleoclimate Applications

Jonathan H. Raberg; Edgart Flores; Sarah E. Crump; Greg de Wet; Nadia Dildar; Gifford H. Miller; Áslaug Geirsdóttir; Julio Sepúlveda

doi:10.1029/2022JG006969

Intact Polar brGDGTs in Arctic Lake Catchments: Implications for Lipid Sources and Paleoclimate Applications

Jonathan H. Raberg^*, Edgart Flores, Sarah E. Crump, Greg de Wet, Nadia Dildar, Gifford H. Miller, Áslaug Geirsdóttir, Julio Sepúlveda

^*Corresponding author for this work

Faculty of Earth Sciences

Research output: Contribution to journal › Article › peer-review

Abstract

Paleotemperature histories derived from lake sediment archives provide valuable context for modern and future climate changes. Branched glycerol dialkyl glycerol tetraether (brGDGT) lipids are a valuable tool in such pursuits due to their empirical correlation with temperature and near ubiquity in nature. However, the relative contributions of terrestrial and lacustrine sources of brGDGTs to lake sediments is site-dependent and difficult to constrain. Here, we explored the potential for intact brGDGTs—the complete lipids with polar head groups (HGs) still attached—to provide insight into the sources of brGDGTs on the landscape and their contributions to the sedimentary record in a set of Arctic lakes. We measured core and intact brGDGTs in soils, surface and downcore sediments, water filtrates, and sediment traps across five lake catchments in the Eastern Canadian Arctic, with an emphasis on Lake Qaupat (QPT), Baffin Island. Soils were dominated by brGDGTs with a monoglycosyl (1G) HG, while lacustrine samples contained more phosphohexose (PH) brGDGTs, providing evidence for in situ brGDGT production in both settings. Core- and PH-brGDGT-IIIa were more abundant in sediments than in the soils or water column, implying an additional post-depositional source of brGDGTs. A hierarchical clustering analysis indicated that core brGDGTs in Lake QPT sediments were largely lacustrine in origin, while 1G-brGDGTs were primarily soil-derived. Additionally, we found evidence for preservation of intact brGDGTs—especially 1G-brGDGTs—downcore on thousand-year timespans, though in situ production deeper in the sediment column cannot be ruled out. Finally, we explored the possibility of reconstructing 1G-brGDGT-derived soil temperatures and core-brGDGT-derived lake temperatures in tandem from sedimentary archives.

Original language	English
Article number	e2022JG006969
Journal	Journal of Geophysical Research: Biogeosciences
Volume	127
Issue number	10
DOIs	https://doi.org/10.1029/2022JG006969
Publication status	Published - 27 Sept 2022

Bibliographical note

Funding Information:
This work was supported by the National Science Foundation (OPP-1737712 to GHM and JS; DDRI-1657743 to GHM and SEC), a Doctoral Grant from the University of Iceland and a project grant from the University of Iceland Research Fund to ÁG and JHR, a National Geographic Society Early Career Grant (#CP-019ER-17 to SEC), the Department of Geological Sciences, and the University of Colorado Boulder. We thank the Inuit of Nunavut and Nunavik for permitting access to their land and to sample soils and lake sediment (Scientific Research Licenses 01022 17R-M, 02034 18R-M, and 02038 19R-M) and the Qikiqtani Inuit of Iqaluit, Qikiqtarjuaq, and Clyde River for assistance in the field. We thank the Nunavut Research Institute for logistical assistance and the Polar Continental Shelf Project for air support. Field research benefited from the assistance of Martha Raynolds and Shawnee Kasanke. We additionally thank Sebastian Cantarero and Katie Rempfert for laboratory assistance and Neal Michelutti for providing lake water chemistry data. We thank Chuanlun Zhang and an anonymous reviewer for helpful feedback that greatly improved the quality of this manuscript.

Funding Information:
This work was supported by the National Science Foundation (OPP‐1737712 to GHM and JS; DDRI‐1657743 to GHM and SEC), a Doctoral Grant from the University of Iceland and a project grant from the University of Iceland Research Fund to ÁG and JHR, a National Geographic Society Early Career Grant (#CP‐019ER‐17 to SEC), the Department of Geological Sciences, and the University of Colorado Boulder. We thank the Inuit of Nunavut and Nunavik for permitting access to their land and to sample soils and lake sediment (Scientific Research Licenses 01022 17R‐M, 02034 18R‐M, and 02038 19R‐M) and the Qikiqtani Inuit of Iqaluit, Qikiqtarjuaq, and Clyde River for assistance in the field. We thank the Nunavut Research Institute for logistical assistance and the Polar Continental Shelf Project for air support. Field research benefited from the assistance of Martha Raynolds and Shawnee Kasanke. We additionally thank Sebastian Cantarero and Katie Rempfert for laboratory assistance and Neal Michelutti for providing lake water chemistry data. We thank Chuanlun Zhang and an anonymous reviewer for helpful feedback that greatly improved the quality of this manuscript.

Publisher Copyright:
© 2022. The Authors.

Other keywords

Arctic
biomarker
brGDGT
intact polar lipid
lake sediment
paleoclimate

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10.1029/2022JG006969

Cite this

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title = "Intact Polar brGDGTs in Arctic Lake Catchments: Implications for Lipid Sources and Paleoclimate Applications",

abstract = "Paleotemperature histories derived from lake sediment archives provide valuable context for modern and future climate changes. Branched glycerol dialkyl glycerol tetraether (brGDGT) lipids are a valuable tool in such pursuits due to their empirical correlation with temperature and near ubiquity in nature. However, the relative contributions of terrestrial and lacustrine sources of brGDGTs to lake sediments is site-dependent and difficult to constrain. Here, we explored the potential for intact brGDGTs—the complete lipids with polar head groups (HGs) still attached—to provide insight into the sources of brGDGTs on the landscape and their contributions to the sedimentary record in a set of Arctic lakes. We measured core and intact brGDGTs in soils, surface and downcore sediments, water filtrates, and sediment traps across five lake catchments in the Eastern Canadian Arctic, with an emphasis on Lake Qaupat (QPT), Baffin Island. Soils were dominated by brGDGTs with a monoglycosyl (1G) HG, while lacustrine samples contained more phosphohexose (PH) brGDGTs, providing evidence for in situ brGDGT production in both settings. Core- and PH-brGDGT-IIIa were more abundant in sediments than in the soils or water column, implying an additional post-depositional source of brGDGTs. A hierarchical clustering analysis indicated that core brGDGTs in Lake QPT sediments were largely lacustrine in origin, while 1G-brGDGTs were primarily soil-derived. Additionally, we found evidence for preservation of intact brGDGTs—especially 1G-brGDGTs—downcore on thousand-year timespans, though in situ production deeper in the sediment column cannot be ruled out. Finally, we explored the possibility of reconstructing 1G-brGDGT-derived soil temperatures and core-brGDGT-derived lake temperatures in tandem from sedimentary archives.",

keywords = "Arctic, biomarker, brGDGT, intact polar lipid, lake sediment, paleoclimate",

author = "Raberg, {Jonathan H.} and Edgart Flores and Crump, {Sarah E.} and {de Wet}, Greg and Nadia Dildar and Miller, {Gifford H.} and {\'A}slaug Geirsd{\'o}ttir and Julio Sep{\'u}lveda",

note = "Funding Information: This work was supported by the National Science Foundation (OPP-1737712 to GHM and JS; DDRI-1657743 to GHM and SEC), a Doctoral Grant from the University of Iceland and a project grant from the University of Iceland Research Fund to {\'A}G and JHR, a National Geographic Society Early Career Grant (#CP-019ER-17 to SEC), the Department of Geological Sciences, and the University of Colorado Boulder. We thank the Inuit of Nunavut and Nunavik for permitting access to their land and to sample soils and lake sediment (Scientific Research Licenses 01022 17R-M, 02034 18R-M, and 02038 19R-M) and the Qikiqtani Inuit of Iqaluit, Qikiqtarjuaq, and Clyde River for assistance in the field. We thank the Nunavut Research Institute for logistical assistance and the Polar Continental Shelf Project for air support. Field research benefited from the assistance of Martha Raynolds and Shawnee Kasanke. We additionally thank Sebastian Cantarero and Katie Rempfert for laboratory assistance and Neal Michelutti for providing lake water chemistry data. We thank Chuanlun Zhang and an anonymous reviewer for helpful feedback that greatly improved the quality of this manuscript. Funding Information: This work was supported by the National Science Foundation (OPP‐1737712 to GHM and JS; DDRI‐1657743 to GHM and SEC), a Doctoral Grant from the University of Iceland and a project grant from the University of Iceland Research Fund to {\'A}G and JHR, a National Geographic Society Early Career Grant (#CP‐019ER‐17 to SEC), the Department of Geological Sciences, and the University of Colorado Boulder. We thank the Inuit of Nunavut and Nunavik for permitting access to their land and to sample soils and lake sediment (Scientific Research Licenses 01022 17R‐M, 02034 18R‐M, and 02038 19R‐M) and the Qikiqtani Inuit of Iqaluit, Qikiqtarjuaq, and Clyde River for assistance in the field. We thank the Nunavut Research Institute for logistical assistance and the Polar Continental Shelf Project for air support. Field research benefited from the assistance of Martha Raynolds and Shawnee Kasanke. We additionally thank Sebastian Cantarero and Katie Rempfert for laboratory assistance and Neal Michelutti for providing lake water chemistry data. We thank Chuanlun Zhang and an anonymous reviewer for helpful feedback that greatly improved the quality of this manuscript. Publisher Copyright: {\textcopyright} 2022. The Authors.",

year = "2022",

month = sep,

day = "27",

doi = "10.1029/2022JG006969",

language = "English",

volume = "127",

journal = "Journal of Geophysical Research: Biogeosciences",

issn = "2169-8953",

publisher = "John Wiley and Sons Inc.",

number = "10",

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TY - JOUR

T1 - Intact Polar brGDGTs in Arctic Lake Catchments

T2 - Implications for Lipid Sources and Paleoclimate Applications

AU - Raberg, Jonathan H.

AU - Flores, Edgart

AU - Crump, Sarah E.

AU - de Wet, Greg

AU - Dildar, Nadia

AU - Miller, Gifford H.

AU - Geirsdóttir, Áslaug

AU - Sepúlveda, Julio

N1 - Funding Information: This work was supported by the National Science Foundation (OPP-1737712 to GHM and JS; DDRI-1657743 to GHM and SEC), a Doctoral Grant from the University of Iceland and a project grant from the University of Iceland Research Fund to ÁG and JHR, a National Geographic Society Early Career Grant (#CP-019ER-17 to SEC), the Department of Geological Sciences, and the University of Colorado Boulder. We thank the Inuit of Nunavut and Nunavik for permitting access to their land and to sample soils and lake sediment (Scientific Research Licenses 01022 17R-M, 02034 18R-M, and 02038 19R-M) and the Qikiqtani Inuit of Iqaluit, Qikiqtarjuaq, and Clyde River for assistance in the field. We thank the Nunavut Research Institute for logistical assistance and the Polar Continental Shelf Project for air support. Field research benefited from the assistance of Martha Raynolds and Shawnee Kasanke. We additionally thank Sebastian Cantarero and Katie Rempfert for laboratory assistance and Neal Michelutti for providing lake water chemistry data. We thank Chuanlun Zhang and an anonymous reviewer for helpful feedback that greatly improved the quality of this manuscript. Funding Information: This work was supported by the National Science Foundation (OPP‐1737712 to GHM and JS; DDRI‐1657743 to GHM and SEC), a Doctoral Grant from the University of Iceland and a project grant from the University of Iceland Research Fund to ÁG and JHR, a National Geographic Society Early Career Grant (#CP‐019ER‐17 to SEC), the Department of Geological Sciences, and the University of Colorado Boulder. We thank the Inuit of Nunavut and Nunavik for permitting access to their land and to sample soils and lake sediment (Scientific Research Licenses 01022 17R‐M, 02034 18R‐M, and 02038 19R‐M) and the Qikiqtani Inuit of Iqaluit, Qikiqtarjuaq, and Clyde River for assistance in the field. We thank the Nunavut Research Institute for logistical assistance and the Polar Continental Shelf Project for air support. Field research benefited from the assistance of Martha Raynolds and Shawnee Kasanke. We additionally thank Sebastian Cantarero and Katie Rempfert for laboratory assistance and Neal Michelutti for providing lake water chemistry data. We thank Chuanlun Zhang and an anonymous reviewer for helpful feedback that greatly improved the quality of this manuscript. Publisher Copyright: © 2022. The Authors.

PY - 2022/9/27

Y1 - 2022/9/27

N2 - Paleotemperature histories derived from lake sediment archives provide valuable context for modern and future climate changes. Branched glycerol dialkyl glycerol tetraether (brGDGT) lipids are a valuable tool in such pursuits due to their empirical correlation with temperature and near ubiquity in nature. However, the relative contributions of terrestrial and lacustrine sources of brGDGTs to lake sediments is site-dependent and difficult to constrain. Here, we explored the potential for intact brGDGTs—the complete lipids with polar head groups (HGs) still attached—to provide insight into the sources of brGDGTs on the landscape and their contributions to the sedimentary record in a set of Arctic lakes. We measured core and intact brGDGTs in soils, surface and downcore sediments, water filtrates, and sediment traps across five lake catchments in the Eastern Canadian Arctic, with an emphasis on Lake Qaupat (QPT), Baffin Island. Soils were dominated by brGDGTs with a monoglycosyl (1G) HG, while lacustrine samples contained more phosphohexose (PH) brGDGTs, providing evidence for in situ brGDGT production in both settings. Core- and PH-brGDGT-IIIa were more abundant in sediments than in the soils or water column, implying an additional post-depositional source of brGDGTs. A hierarchical clustering analysis indicated that core brGDGTs in Lake QPT sediments were largely lacustrine in origin, while 1G-brGDGTs were primarily soil-derived. Additionally, we found evidence for preservation of intact brGDGTs—especially 1G-brGDGTs—downcore on thousand-year timespans, though in situ production deeper in the sediment column cannot be ruled out. Finally, we explored the possibility of reconstructing 1G-brGDGT-derived soil temperatures and core-brGDGT-derived lake temperatures in tandem from sedimentary archives.

AB - Paleotemperature histories derived from lake sediment archives provide valuable context for modern and future climate changes. Branched glycerol dialkyl glycerol tetraether (brGDGT) lipids are a valuable tool in such pursuits due to their empirical correlation with temperature and near ubiquity in nature. However, the relative contributions of terrestrial and lacustrine sources of brGDGTs to lake sediments is site-dependent and difficult to constrain. Here, we explored the potential for intact brGDGTs—the complete lipids with polar head groups (HGs) still attached—to provide insight into the sources of brGDGTs on the landscape and their contributions to the sedimentary record in a set of Arctic lakes. We measured core and intact brGDGTs in soils, surface and downcore sediments, water filtrates, and sediment traps across five lake catchments in the Eastern Canadian Arctic, with an emphasis on Lake Qaupat (QPT), Baffin Island. Soils were dominated by brGDGTs with a monoglycosyl (1G) HG, while lacustrine samples contained more phosphohexose (PH) brGDGTs, providing evidence for in situ brGDGT production in both settings. Core- and PH-brGDGT-IIIa were more abundant in sediments than in the soils or water column, implying an additional post-depositional source of brGDGTs. A hierarchical clustering analysis indicated that core brGDGTs in Lake QPT sediments were largely lacustrine in origin, while 1G-brGDGTs were primarily soil-derived. Additionally, we found evidence for preservation of intact brGDGTs—especially 1G-brGDGTs—downcore on thousand-year timespans, though in situ production deeper in the sediment column cannot be ruled out. Finally, we explored the possibility of reconstructing 1G-brGDGT-derived soil temperatures and core-brGDGT-derived lake temperatures in tandem from sedimentary archives.

KW - Arctic

KW - biomarker

KW - brGDGT

KW - intact polar lipid

KW - lake sediment

KW - paleoclimate

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U2 - 10.1029/2022JG006969

DO - 10.1029/2022JG006969

M3 - Article

AN - SCOPUS:85141221019

SN - 2169-8953

VL - 127

JO - Journal of Geophysical Research: Biogeosciences

JF - Journal of Geophysical Research: Biogeosciences

IS - 10

M1 - e2022JG006969

ER -

Intact Polar brGDGTs in Arctic Lake Catchments: Implications for Lipid Sources and Paleoclimate Applications

Abstract

Bibliographical note

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