Contrasting Common Era climate and hydrology sensitivities from paired lake sediment dinosterol hydrogen isotope records in the South Pacific Convergence Zone

Ashley E. Maloney; Julie N. Richey; Daniel B. Nelson; Samantha N. Hing; David A. Sear; Jonathan D. Hassall; Peter G. Langdon; Ursula Sichrowsky; Robert Schabetsberger; Atoloto Malau; Jean Yves Meyer; Ian W. Croudace; Julian P. Sachs

doi:10.1016/j.quascirev.2022.107421

Contrasting Common Era climate and hydrology sensitivities from paired lake sediment dinosterol hydrogen isotope records in the South Pacific Convergence Zone

Ashley E. Maloney, Julie N. Richey, Daniel B. Nelson, Samantha N. Hing, David A. Sear, Jonathan D. Hassall, Peter G. Langdon, Ursula Sichrowsky, Robert Schabetsberger, Atoloto Malau, Jean Yves Meyer, Ian W. Croudace, Julian P. Sachs

Continental Scientific Drilling Facility

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

7 Scopus citations

Abstract

Hydroclimate on ‘Uvea (Wallis et Futuna) is controlled by rainfall associated with the South Pacific Convergence Zone (SPCZ), the southern hemisphere's largest precipitation feature. To extend the short observational precipitation record, the hydrogen isotopic composition of the algal lipid biomarker dinosterol (δ²H_dinosterol) was measured in sediment cores from two volcanic crater lakes on ‘Uvea. The modern lakes differ morphologically and chemically but both contain freshwater within the photic zone, support phytoplankton communities inclusive of dinosterol-producing dinoflagellates, and experience identical climate conditions. δ²H_dinosterol values track lake water isotope ratios, ultimately controlled in the tropics by precipitation amount and evaporative enrichment. However, in 88-m-deep Lac Lalolalo a steadily decreasing trend in sedimentary δ²H_dinosterol values from −227‰ around year 988 CE to modern values as low as −303‰, suggests this lake's evolution from an active volcanic setting to the present system strongly influenced δ²H_dinosterol values. Although current hydrology and water isotope systematics may now reflect precipitation and evaporation in this lake, the interaction between these processes and large changes in basin morphology, geochemistry, and hydrology obstruct the recovery of a climate signal from Lac Lalolalo's sedimentary δ²H_dinosterol records. This work emphasizes the importance of site replication and the use of complementary climate reconstruction tools, especially when using molecular proxies that may be sensitive to more than one environmental parameter. Contrary to its neighbor, duplicate δ²H_dinosterol records from 23-m-deep Lac Lanutavake varied between −277‰ and −297‰ and indicate slightly drier conditions during the time-period known as the Medieval Climate Anomaly (MCA, 950–1250 CE). The δ²H_dinosterol signal in Lac Lanutavake was muted compared to published records from ‘Upolu (Samoa) and Efate (Vanuatu) indicating that ‘Uvea's location is not as sensitive to precipitation variability at sites farther from the SPCZ central axis. Lithogenic runoff proxies combined with δ²H_dinosterol support the interpretation of a relatively dry MCA on ‘Uvea, ‘Upolu, and Efate, potentially due to less intense precipitation, a contracted, or a more zonally oriented SPCZ.

Original language	English (US)
Article number	107421
Journal	Quaternary Science Reviews
Volume	281
DOIs	https://doi.org/10.1016/j.quascirev.2022.107421
State	Published - Apr 1 2022

Bibliographical note

Funding Information:
This material is based upon work supported by the US National Science Foundation under Grant Nos. 0823503 and 1502417 to J.P.S. A University of Washington Program on Climate Change Fellowship, IGERT Ocean Change Fellowship [grant #NSF1068839], Princeton University Department of Geosciences Harry H. Hess postdoctoral Fellowship, and Simons Foundation Fellowship [732763] provided partial research support for A.E.M; IGERT Ocean Change mini-research awards, and a University of Washington Quaternary Research Center research award to A.E.M. The Explorers Club Exploration Fund Grant, Gilchrist Expedition Grant and Royal Geographical Society (with IBG) Monica Cole Grant assisted with Samoa travel. Lake Lanoto'o data was funded under a Natural Environment Research Council (NERC) Studentship to J.D.H. Funding for Lake Emaotul research was provided by NERC Grant NE/N006674/1. UBA 14C date was funded by a NERC SPITFIRE PhD Scholarship and sampled by Nichola Strandberg. We are grateful for permission from Wallis civic and traditional authorities. Sample collection in ‘Uvea benefitted from the assistance of K. Manufeki, S. Tauvale, C. Manry and others from Service de L'Environment, M. Fotuaika, J.-F. Poncet, P. Nicomette, S. Felomaki, P. Tauvale, C. Chauvet, and the planning assistance from C. Lique, M. Bridoux, and C. Altman. Field work in ‘Upolu, Samoa was kindly permitted by Taule'ale'ausmai Laavasa Malua, Chief Executive Officer, Niualuga Evaimalo and staff in Ministry Natural Resources and Environment; field assistance was provided by Josie Hill, Lucy, Tinifu, Solomano and Ai. Tom Bishop assisted with field work on Vanuatu. M. Wolfshorndl, T. Magee, J. Rodysill, and K. Brady assisted with splitting and scanning cores at LacCore. We thank C. Kaapu-Lyons, N. Wallsgrove, and B. Popp for analyzing Wallis water samples. T. Fonville performed the preliminary assessment of microfossils. M. Wolhowe and J. Gregerson assisted with instrument maintenance and M. Wolhowe made two new Vanuatu δ2Hdinosterol measurements. D. Xue analyzed ions and metals in Lac Lalolalo samples. Conversations with L. Thompson, S. PoChedley, R. Echols, J. Scheff, S. Rushley, D. Battisti, R. Wood, K. Thirumalai, N. Williams, W.J. D'Andrea and constructive comments from A.E. Ingalls, and P. Quay greatly improved this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. We thank S.N. Ladd for providing careful feedback on this project and helpful edits on the manuscript. We thank Editor P. Rioual and two anonymous reviewers for their helpful and constructive comments that improved this work.

Funding Information:
This material is based upon work supported by the US National Science Foundation under Grant Nos. 0823503 and 1502417 to J.P.S. A University of Washington Program on Climate Change Fellowship, IGERT Ocean Change Fellowship [grant # NSF1068839 ], Princeton University Department of Geosciences Harry H. Hess postdoctoral Fellowship, and Simons Foundation Fellowship [ 732763 ] provided partial research support for A.E.M; IGERT Ocean Change mini-research awards, and a University of Washington Quaternary Research Center research award to A.E.M. The Explorers Club Exploration Fund Grant, Gilchrist Expedition Grant and Royal Geographical Society (with IBG) Monica Cole Grant assisted with Samoa travel. Lake Lanoto'o data was funded under a Natural Environment Research Council ( NERC ) Studentship to J.D.H. Funding for Lake Emaotul research was provided by NERC Grant NE/N006674/1 . UBA 14 C date was funded by a NERC SPITFIRE PhD Scholarship and sampled by Nichola Strandberg. We are grateful for permission from Wallis civic and traditional authorities. Sample collection in ‘Uvea benefitted from the assistance of K. Manufeki, S. Tauvale, C. Manry and others from Service de L'Environment, M. Fotuaika, J.-F. Poncet, P. Nicomette, S. Felomaki, P. Tauvale, C. Chauvet, and the planning assistance from C. Lique, M. Bridoux, and C. Altman. Field work in ‘Upolu, Samoa was kindly permitted by Taule'ale'ausmai Laavasa Malua, Chief Executive Officer, Niualuga Evaimalo and staff in Ministry Natural Resources and Environment; field assistance was provided by Josie Hill, Lucy, Tinifu, Solomano and Ai. Tom Bishop assisted with field work on Vanuatu. M. Wolfshorndl, T. Magee, J. Rodysill, and K. Brady assisted with splitting and scanning cores at LacCore. We thank C. Kaapu-Lyons, N. Wallsgrove, and B. Popp for analyzing Wallis water samples. T. Fonville performed the preliminary assessment of microfossils. M. Wolhowe and J. Gregerson assisted with instrument maintenance and M. Wolhowe made two new Vanuatu δ 2 H dinosterol measurements. D. Xue analyzed ions and metals in Lac Lalolalo samples. Conversations with L. Thompson, S. PoChedley, R. Echols, J. Scheff, S. Rushley, D. Battisti, R. Wood, K. Thirumalai, N. Williams, W.J. D'Andrea and constructive comments from A.E. Ingalls, and P. Quay greatly improved this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government . We thank S.N. Ladd for providing careful feedback on this project and helpful edits on the manuscript. We thank Editor P. Rioual and two anonymous reviewers for their helpful and constructive comments that improved this work.

Publisher Copyright:
© 2022

Keywords

Dinosterol
Holocene
Hydrogen isotopes
Lakes
Organic geochemistry
Paleohydrology
Paleolimnology
Sedimentology
SPCZ
Tropical Pacific

Continental Scientific Drilling Facility tags

SPCZ14

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10.1016/j.quascirev.2022.107421

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Maloney, A. E., Richey, J. N., Nelson, D. B., Hing, S. N., Sear, D. A., Hassall, J. D., Langdon, P. G., Sichrowsky, U., Schabetsberger, R., Malau, A., Meyer, J. Y., Croudace, I. W., & Sachs, J. P. (2022). Contrasting Common Era climate and hydrology sensitivities from paired lake sediment dinosterol hydrogen isotope records in the South Pacific Convergence Zone. Quaternary Science Reviews, 281, Article 107421. https://doi.org/10.1016/j.quascirev.2022.107421

Maloney, AE, Richey, JN, Nelson, DB, Hing, SN, Sear, DA, Hassall, JD, Langdon, PG, Sichrowsky, U, Schabetsberger, R, Malau, A, Meyer, JY, Croudace, IW & Sachs, JP 2022, 'Contrasting Common Era climate and hydrology sensitivities from paired lake sediment dinosterol hydrogen isotope records in the South Pacific Convergence Zone', Quaternary Science Reviews, vol. 281, 107421. https://doi.org/10.1016/j.quascirev.2022.107421

@article{58b6ad3d624d4e7ca1b039a0eef4c75f,

title = "Contrasting Common Era climate and hydrology sensitivities from paired lake sediment dinosterol hydrogen isotope records in the South Pacific Convergence Zone",

abstract = "Hydroclimate on {\textquoteleft}Uvea (Wallis et Futuna) is controlled by rainfall associated with the South Pacific Convergence Zone (SPCZ), the southern hemisphere's largest precipitation feature. To extend the short observational precipitation record, the hydrogen isotopic composition of the algal lipid biomarker dinosterol (δ2Hdinosterol) was measured in sediment cores from two volcanic crater lakes on {\textquoteleft}Uvea. The modern lakes differ morphologically and chemically but both contain freshwater within the photic zone, support phytoplankton communities inclusive of dinosterol-producing dinoflagellates, and experience identical climate conditions. δ2Hdinosterol values track lake water isotope ratios, ultimately controlled in the tropics by precipitation amount and evaporative enrichment. However, in 88-m-deep Lac Lalolalo a steadily decreasing trend in sedimentary δ2Hdinosterol values from −227‰ around year 988 CE to modern values as low as −303‰, suggests this lake's evolution from an active volcanic setting to the present system strongly influenced δ2Hdinosterol values. Although current hydrology and water isotope systematics may now reflect precipitation and evaporation in this lake, the interaction between these processes and large changes in basin morphology, geochemistry, and hydrology obstruct the recovery of a climate signal from Lac Lalolalo's sedimentary δ2Hdinosterol records. This work emphasizes the importance of site replication and the use of complementary climate reconstruction tools, especially when using molecular proxies that may be sensitive to more than one environmental parameter. Contrary to its neighbor, duplicate δ2Hdinosterol records from 23-m-deep Lac Lanutavake varied between −277‰ and −297‰ and indicate slightly drier conditions during the time-period known as the Medieval Climate Anomaly (MCA, 950–1250 CE). The δ2Hdinosterol signal in Lac Lanutavake was muted compared to published records from {\textquoteleft}Upolu (Samoa) and Efate (Vanuatu) indicating that {\textquoteleft}Uvea's location is not as sensitive to precipitation variability at sites farther from the SPCZ central axis. Lithogenic runoff proxies combined with δ2Hdinosterol support the interpretation of a relatively dry MCA on {\textquoteleft}Uvea, {\textquoteleft}Upolu, and Efate, potentially due to less intense precipitation, a contracted, or a more zonally oriented SPCZ.",

keywords = "Dinosterol, Holocene, Hydrogen isotopes, Lakes, Organic geochemistry, Paleohydrology, Paleolimnology, Sedimentology, SPCZ, Tropical Pacific",

author = "Maloney, {Ashley E.} and Richey, {Julie N.} and Nelson, {Daniel B.} and Hing, {Samantha N.} and Sear, {David A.} and Hassall, {Jonathan D.} and Langdon, {Peter G.} and Ursula Sichrowsky and Robert Schabetsberger and Atoloto Malau and Meyer, {Jean Yves} and Croudace, {Ian W.} and Sachs, {Julian P.}",

note = "Funding Information: This material is based upon work supported by the US National Science Foundation under Grant Nos. 0823503 and 1502417 to J.P.S. A University of Washington Program on Climate Change Fellowship, IGERT Ocean Change Fellowship [grant #NSF1068839], Princeton University Department of Geosciences Harry H. Hess postdoctoral Fellowship, and Simons Foundation Fellowship [732763] provided partial research support for A.E.M; IGERT Ocean Change mini-research awards, and a University of Washington Quaternary Research Center research award to A.E.M. The Explorers Club Exploration Fund Grant, Gilchrist Expedition Grant and Royal Geographical Society (with IBG) Monica Cole Grant assisted with Samoa travel. Lake Lanoto'o data was funded under a Natural Environment Research Council (NERC) Studentship to J.D.H. Funding for Lake Emaotul research was provided by NERC Grant NE/N006674/1. UBA 14C date was funded by a NERC SPITFIRE PhD Scholarship and sampled by Nichola Strandberg. We are grateful for permission from Wallis civic and traditional authorities. Sample collection in {\textquoteleft}Uvea benefitted from the assistance of K. Manufeki, S. Tauvale, C. Manry and others from Service de L'Environment, M. Fotuaika, J.-F. Poncet, P. Nicomette, S. Felomaki, P. Tauvale, C. Chauvet, and the planning assistance from C. Lique, M. Bridoux, and C. Altman. Field work in {\textquoteleft}Upolu, Samoa was kindly permitted by Taule'ale'ausmai Laavasa Malua, Chief Executive Officer, Niualuga Evaimalo and staff in Ministry Natural Resources and Environment; field assistance was provided by Josie Hill, Lucy, Tinifu, Solomano and Ai. Tom Bishop assisted with field work on Vanuatu. M. Wolfshorndl, T. Magee, J. Rodysill, and K. Brady assisted with splitting and scanning cores at LacCore. We thank C. Kaapu-Lyons, N. Wallsgrove, and B. Popp for analyzing Wallis water samples. T. Fonville performed the preliminary assessment of microfossils. M. Wolhowe and J. Gregerson assisted with instrument maintenance and M. Wolhowe made two new Vanuatu δ2Hdinosterol measurements. D. Xue analyzed ions and metals in Lac Lalolalo samples. Conversations with L. Thompson, S. PoChedley, R. Echols, J. Scheff, S. Rushley, D. Battisti, R. Wood, K. Thirumalai, N. Williams, W.J. D'Andrea and constructive comments from A.E. Ingalls, and P. Quay greatly improved this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. We thank S.N. Ladd for providing careful feedback on this project and helpful edits on the manuscript. We thank Editor P. Rioual and two anonymous reviewers for their helpful and constructive comments that improved this work. Funding Information: This material is based upon work supported by the US National Science Foundation under Grant Nos. 0823503 and 1502417 to J.P.S. A University of Washington Program on Climate Change Fellowship, IGERT Ocean Change Fellowship [grant # NSF1068839 ], Princeton University Department of Geosciences Harry H. Hess postdoctoral Fellowship, and Simons Foundation Fellowship [ 732763 ] provided partial research support for A.E.M; IGERT Ocean Change mini-research awards, and a University of Washington Quaternary Research Center research award to A.E.M. The Explorers Club Exploration Fund Grant, Gilchrist Expedition Grant and Royal Geographical Society (with IBG) Monica Cole Grant assisted with Samoa travel. Lake Lanoto'o data was funded under a Natural Environment Research Council ( NERC ) Studentship to J.D.H. Funding for Lake Emaotul research was provided by NERC Grant NE/N006674/1 . UBA 14 C date was funded by a NERC SPITFIRE PhD Scholarship and sampled by Nichola Strandberg. We are grateful for permission from Wallis civic and traditional authorities. Sample collection in {\textquoteleft}Uvea benefitted from the assistance of K. Manufeki, S. Tauvale, C. Manry and others from Service de L'Environment, M. Fotuaika, J.-F. Poncet, P. Nicomette, S. Felomaki, P. Tauvale, C. Chauvet, and the planning assistance from C. Lique, M. Bridoux, and C. Altman. Field work in {\textquoteleft}Upolu, Samoa was kindly permitted by Taule'ale'ausmai Laavasa Malua, Chief Executive Officer, Niualuga Evaimalo and staff in Ministry Natural Resources and Environment; field assistance was provided by Josie Hill, Lucy, Tinifu, Solomano and Ai. Tom Bishop assisted with field work on Vanuatu. M. Wolfshorndl, T. Magee, J. Rodysill, and K. Brady assisted with splitting and scanning cores at LacCore. We thank C. Kaapu-Lyons, N. Wallsgrove, and B. Popp for analyzing Wallis water samples. T. Fonville performed the preliminary assessment of microfossils. M. Wolhowe and J. Gregerson assisted with instrument maintenance and M. Wolhowe made two new Vanuatu δ 2 H dinosterol measurements. D. Xue analyzed ions and metals in Lac Lalolalo samples. Conversations with L. Thompson, S. PoChedley, R. Echols, J. Scheff, S. Rushley, D. Battisti, R. Wood, K. Thirumalai, N. Williams, W.J. D'Andrea and constructive comments from A.E. Ingalls, and P. Quay greatly improved this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government . We thank S.N. Ladd for providing careful feedback on this project and helpful edits on the manuscript. We thank Editor P. Rioual and two anonymous reviewers for their helpful and constructive comments that improved this work. Publisher Copyright: {\textcopyright} 2022",

year = "2022",

month = apr,

day = "1",

doi = "10.1016/j.quascirev.2022.107421",

language = "English (US)",

volume = "281",

journal = "Quaternary Science Reviews",

issn = "0277-3791",

publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Contrasting Common Era climate and hydrology sensitivities from paired lake sediment dinosterol hydrogen isotope records in the South Pacific Convergence Zone

AU - Maloney, Ashley E.

AU - Richey, Julie N.

AU - Nelson, Daniel B.

AU - Hing, Samantha N.

AU - Sear, David A.

AU - Hassall, Jonathan D.

AU - Langdon, Peter G.

AU - Sichrowsky, Ursula

AU - Schabetsberger, Robert

AU - Malau, Atoloto

AU - Meyer, Jean Yves

AU - Croudace, Ian W.

AU - Sachs, Julian P.

N1 - Funding Information: This material is based upon work supported by the US National Science Foundation under Grant Nos. 0823503 and 1502417 to J.P.S. A University of Washington Program on Climate Change Fellowship, IGERT Ocean Change Fellowship [grant #NSF1068839], Princeton University Department of Geosciences Harry H. Hess postdoctoral Fellowship, and Simons Foundation Fellowship [732763] provided partial research support for A.E.M; IGERT Ocean Change mini-research awards, and a University of Washington Quaternary Research Center research award to A.E.M. The Explorers Club Exploration Fund Grant, Gilchrist Expedition Grant and Royal Geographical Society (with IBG) Monica Cole Grant assisted with Samoa travel. Lake Lanoto'o data was funded under a Natural Environment Research Council (NERC) Studentship to J.D.H. Funding for Lake Emaotul research was provided by NERC Grant NE/N006674/1. UBA 14C date was funded by a NERC SPITFIRE PhD Scholarship and sampled by Nichola Strandberg. We are grateful for permission from Wallis civic and traditional authorities. Sample collection in ‘Uvea benefitted from the assistance of K. Manufeki, S. Tauvale, C. Manry and others from Service de L'Environment, M. Fotuaika, J.-F. Poncet, P. Nicomette, S. Felomaki, P. Tauvale, C. Chauvet, and the planning assistance from C. Lique, M. Bridoux, and C. Altman. Field work in ‘Upolu, Samoa was kindly permitted by Taule'ale'ausmai Laavasa Malua, Chief Executive Officer, Niualuga Evaimalo and staff in Ministry Natural Resources and Environment; field assistance was provided by Josie Hill, Lucy, Tinifu, Solomano and Ai. Tom Bishop assisted with field work on Vanuatu. M. Wolfshorndl, T. Magee, J. Rodysill, and K. Brady assisted with splitting and scanning cores at LacCore. We thank C. Kaapu-Lyons, N. Wallsgrove, and B. Popp for analyzing Wallis water samples. T. Fonville performed the preliminary assessment of microfossils. M. Wolhowe and J. Gregerson assisted with instrument maintenance and M. Wolhowe made two new Vanuatu δ2Hdinosterol measurements. D. Xue analyzed ions and metals in Lac Lalolalo samples. Conversations with L. Thompson, S. PoChedley, R. Echols, J. Scheff, S. Rushley, D. Battisti, R. Wood, K. Thirumalai, N. Williams, W.J. D'Andrea and constructive comments from A.E. Ingalls, and P. Quay greatly improved this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. We thank S.N. Ladd for providing careful feedback on this project and helpful edits on the manuscript. We thank Editor P. Rioual and two anonymous reviewers for their helpful and constructive comments that improved this work. Funding Information: This material is based upon work supported by the US National Science Foundation under Grant Nos. 0823503 and 1502417 to J.P.S. A University of Washington Program on Climate Change Fellowship, IGERT Ocean Change Fellowship [grant # NSF1068839 ], Princeton University Department of Geosciences Harry H. Hess postdoctoral Fellowship, and Simons Foundation Fellowship [ 732763 ] provided partial research support for A.E.M; IGERT Ocean Change mini-research awards, and a University of Washington Quaternary Research Center research award to A.E.M. The Explorers Club Exploration Fund Grant, Gilchrist Expedition Grant and Royal Geographical Society (with IBG) Monica Cole Grant assisted with Samoa travel. Lake Lanoto'o data was funded under a Natural Environment Research Council ( NERC ) Studentship to J.D.H. Funding for Lake Emaotul research was provided by NERC Grant NE/N006674/1 . UBA 14 C date was funded by a NERC SPITFIRE PhD Scholarship and sampled by Nichola Strandberg. We are grateful for permission from Wallis civic and traditional authorities. Sample collection in ‘Uvea benefitted from the assistance of K. Manufeki, S. Tauvale, C. Manry and others from Service de L'Environment, M. Fotuaika, J.-F. Poncet, P. Nicomette, S. Felomaki, P. Tauvale, C. Chauvet, and the planning assistance from C. Lique, M. Bridoux, and C. Altman. Field work in ‘Upolu, Samoa was kindly permitted by Taule'ale'ausmai Laavasa Malua, Chief Executive Officer, Niualuga Evaimalo and staff in Ministry Natural Resources and Environment; field assistance was provided by Josie Hill, Lucy, Tinifu, Solomano and Ai. Tom Bishop assisted with field work on Vanuatu. M. Wolfshorndl, T. Magee, J. Rodysill, and K. Brady assisted with splitting and scanning cores at LacCore. We thank C. Kaapu-Lyons, N. Wallsgrove, and B. Popp for analyzing Wallis water samples. T. Fonville performed the preliminary assessment of microfossils. M. Wolhowe and J. Gregerson assisted with instrument maintenance and M. Wolhowe made two new Vanuatu δ 2 H dinosterol measurements. D. Xue analyzed ions and metals in Lac Lalolalo samples. Conversations with L. Thompson, S. PoChedley, R. Echols, J. Scheff, S. Rushley, D. Battisti, R. Wood, K. Thirumalai, N. Williams, W.J. D'Andrea and constructive comments from A.E. Ingalls, and P. Quay greatly improved this manuscript. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government . We thank S.N. Ladd for providing careful feedback on this project and helpful edits on the manuscript. We thank Editor P. Rioual and two anonymous reviewers for their helpful and constructive comments that improved this work. Publisher Copyright: © 2022

PY - 2022/4/1

Y1 - 2022/4/1

N2 - Hydroclimate on ‘Uvea (Wallis et Futuna) is controlled by rainfall associated with the South Pacific Convergence Zone (SPCZ), the southern hemisphere's largest precipitation feature. To extend the short observational precipitation record, the hydrogen isotopic composition of the algal lipid biomarker dinosterol (δ2Hdinosterol) was measured in sediment cores from two volcanic crater lakes on ‘Uvea. The modern lakes differ morphologically and chemically but both contain freshwater within the photic zone, support phytoplankton communities inclusive of dinosterol-producing dinoflagellates, and experience identical climate conditions. δ2Hdinosterol values track lake water isotope ratios, ultimately controlled in the tropics by precipitation amount and evaporative enrichment. However, in 88-m-deep Lac Lalolalo a steadily decreasing trend in sedimentary δ2Hdinosterol values from −227‰ around year 988 CE to modern values as low as −303‰, suggests this lake's evolution from an active volcanic setting to the present system strongly influenced δ2Hdinosterol values. Although current hydrology and water isotope systematics may now reflect precipitation and evaporation in this lake, the interaction between these processes and large changes in basin morphology, geochemistry, and hydrology obstruct the recovery of a climate signal from Lac Lalolalo's sedimentary δ2Hdinosterol records. This work emphasizes the importance of site replication and the use of complementary climate reconstruction tools, especially when using molecular proxies that may be sensitive to more than one environmental parameter. Contrary to its neighbor, duplicate δ2Hdinosterol records from 23-m-deep Lac Lanutavake varied between −277‰ and −297‰ and indicate slightly drier conditions during the time-period known as the Medieval Climate Anomaly (MCA, 950–1250 CE). The δ2Hdinosterol signal in Lac Lanutavake was muted compared to published records from ‘Upolu (Samoa) and Efate (Vanuatu) indicating that ‘Uvea's location is not as sensitive to precipitation variability at sites farther from the SPCZ central axis. Lithogenic runoff proxies combined with δ2Hdinosterol support the interpretation of a relatively dry MCA on ‘Uvea, ‘Upolu, and Efate, potentially due to less intense precipitation, a contracted, or a more zonally oriented SPCZ.

AB - Hydroclimate on ‘Uvea (Wallis et Futuna) is controlled by rainfall associated with the South Pacific Convergence Zone (SPCZ), the southern hemisphere's largest precipitation feature. To extend the short observational precipitation record, the hydrogen isotopic composition of the algal lipid biomarker dinosterol (δ2Hdinosterol) was measured in sediment cores from two volcanic crater lakes on ‘Uvea. The modern lakes differ morphologically and chemically but both contain freshwater within the photic zone, support phytoplankton communities inclusive of dinosterol-producing dinoflagellates, and experience identical climate conditions. δ2Hdinosterol values track lake water isotope ratios, ultimately controlled in the tropics by precipitation amount and evaporative enrichment. However, in 88-m-deep Lac Lalolalo a steadily decreasing trend in sedimentary δ2Hdinosterol values from −227‰ around year 988 CE to modern values as low as −303‰, suggests this lake's evolution from an active volcanic setting to the present system strongly influenced δ2Hdinosterol values. Although current hydrology and water isotope systematics may now reflect precipitation and evaporation in this lake, the interaction between these processes and large changes in basin morphology, geochemistry, and hydrology obstruct the recovery of a climate signal from Lac Lalolalo's sedimentary δ2Hdinosterol records. This work emphasizes the importance of site replication and the use of complementary climate reconstruction tools, especially when using molecular proxies that may be sensitive to more than one environmental parameter. Contrary to its neighbor, duplicate δ2Hdinosterol records from 23-m-deep Lac Lanutavake varied between −277‰ and −297‰ and indicate slightly drier conditions during the time-period known as the Medieval Climate Anomaly (MCA, 950–1250 CE). The δ2Hdinosterol signal in Lac Lanutavake was muted compared to published records from ‘Upolu (Samoa) and Efate (Vanuatu) indicating that ‘Uvea's location is not as sensitive to precipitation variability at sites farther from the SPCZ central axis. Lithogenic runoff proxies combined with δ2Hdinosterol support the interpretation of a relatively dry MCA on ‘Uvea, ‘Upolu, and Efate, potentially due to less intense precipitation, a contracted, or a more zonally oriented SPCZ.

KW - Dinosterol

KW - Holocene

KW - Hydrogen isotopes

KW - Lakes

KW - Organic geochemistry

KW - Paleohydrology

KW - Paleolimnology

KW - Sedimentology

KW - SPCZ

KW - Tropical Pacific

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UR - http://www.scopus.com/inward/citedby.url?scp=85125497901&partnerID=8YFLogxK

U2 - 10.1016/j.quascirev.2022.107421

DO - 10.1016/j.quascirev.2022.107421

M3 - Article

AN - SCOPUS:85125497901

SN - 0277-3791

VL - 281

JO - Quaternary Science Reviews

JF - Quaternary Science Reviews

M1 - 107421

ER -

Contrasting Common Era climate and hydrology sensitivities from paired lake sediment dinosterol hydrogen isotope records in the South Pacific Convergence Zone

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