How to Deal With Multi-Proxy Data for Paleoenvironmental Reconstructions: Applications to a Holocene Lake Sediment Record From the Tian Shan, Central Asia

Multi-proxy investigations on geological archives provide valuable information about environmental variations in the past. As opposed to single-proxy studies, the combination of several proxies can reveal more detailed information and strengthen subsequent paleoenvironmental reconstructions. However...

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Main Authors: Natalie Schroeter, Jaime L. Toney, Stefan Lauterbach, Julia Kalanke, Anja Schwarz, Stefan Schouten, Gerd Gleixner
Format: Article
Language:English
Published: Frontiers Media S.A. 2020-09-01
Series:Frontiers in Earth Science
Subjects:
Online Access:https://www.frontiersin.org/article/10.3389/feart.2020.00353/full
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spelling doaj-e5f71dbf2d8a4ed0bfa0e27f42a53bd12020-11-25T03:19:58ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632020-09-01810.3389/feart.2020.00353570299How to Deal With Multi-Proxy Data for Paleoenvironmental Reconstructions: Applications to a Holocene Lake Sediment Record From the Tian Shan, Central AsiaNatalie Schroeter0Jaime L. Toney1Stefan Lauterbach2Stefan Lauterbach3Julia Kalanke4Anja Schwarz5Stefan Schouten6Stefan Schouten7Gerd Gleixner8Max Planck Institute for Biogeochemistry, Research Group Molecular Biogeochemistry, Jena, GermanySchool of Geographical and Earth Sciences, University of Glasgow, Glasgow, United KingdomKiel University, Leibniz Laboratory for Radiometric Dating and Stable Isotope Research, Kiel, GermanyKiel University, Institute of Geosciences, Kiel, GermanySection 4.3 – Climate Dynamics and Landscape Evolution, GFZ German Research Centre for Geosciences, Potsdam, GermanyTechnische Universität Braunschweig, Institute of Geosystems and Bioindication, Braunschweig, GermanyDepartment of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Den Burg, NetherlandsDepartment of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, NetherlandsMax Planck Institute for Biogeochemistry, Research Group Molecular Biogeochemistry, Jena, GermanyMulti-proxy investigations on geological archives provide valuable information about environmental variations in the past. As opposed to single-proxy studies, the combination of several proxies can reveal more detailed information and strengthen subsequent paleoenvironmental reconstructions. However, there is still no consensus about how to deal with resulting highly dimensional datasets in a statistical manner. In many cases, the interpretations of multi-proxy datasets rely on visually matching several proxy records, which can lead to incorrect or insufficient interpretations. Here we report an innovative approach that combines the novel dimension reduction technique Uniform Manifold Approximation and Projection (UMAP) and the time series analysis R package asdetect to identify and characterize Holocene environmental phases and phase boundaries in a sediment core from Lake Chatyr Kol, southern Kyrgyzstan. Despite the fact that the Holocene climate evolution of Central Asia has been intensively studied during the last decades, knowledge about regional climate development during the Holocene and the underlying mechanisms is still relatively scarce. We particularly focus on phase transitions and differentiate between event-based shifts as opposed to gradual phase transitions. For this study, long-chain alkenones were used as a paleotemperature proxy and variations in long-chain alkyl diol distributions were ascribed to relative changes of algal input. The compound-specific stable hydrogen isotope compositions (δD) of individual n-alkanes were utilized as paleohydrological proxies, with the δD of mid-chain n-alkanes reflecting changes in the δD of the lake water and the δD of long-chain n-alkanes recording the δD of the meteoric water. We show the potential of modern analysis tools for data-driven paleoenvironmental reconstructions and advocate for their more frequent implementation in multi-proxy studies.https://www.frontiersin.org/article/10.3389/feart.2020.00353/fullpaleoenvironmentclimate reconstructionsbiomarkerslake sedimentscentral asiamulti-proxy data
collection DOAJ
language English
format Article
sources DOAJ
author Natalie Schroeter
Jaime L. Toney
Stefan Lauterbach
Stefan Lauterbach
Julia Kalanke
Anja Schwarz
Stefan Schouten
Stefan Schouten
Gerd Gleixner
spellingShingle Natalie Schroeter
Jaime L. Toney
Stefan Lauterbach
Stefan Lauterbach
Julia Kalanke
Anja Schwarz
Stefan Schouten
Stefan Schouten
Gerd Gleixner
How to Deal With Multi-Proxy Data for Paleoenvironmental Reconstructions: Applications to a Holocene Lake Sediment Record From the Tian Shan, Central Asia
Frontiers in Earth Science
paleoenvironment
climate reconstructions
biomarkers
lake sediments
central asia
multi-proxy data
author_facet Natalie Schroeter
Jaime L. Toney
Stefan Lauterbach
Stefan Lauterbach
Julia Kalanke
Anja Schwarz
Stefan Schouten
Stefan Schouten
Gerd Gleixner
author_sort Natalie Schroeter
title How to Deal With Multi-Proxy Data for Paleoenvironmental Reconstructions: Applications to a Holocene Lake Sediment Record From the Tian Shan, Central Asia
title_short How to Deal With Multi-Proxy Data for Paleoenvironmental Reconstructions: Applications to a Holocene Lake Sediment Record From the Tian Shan, Central Asia
title_full How to Deal With Multi-Proxy Data for Paleoenvironmental Reconstructions: Applications to a Holocene Lake Sediment Record From the Tian Shan, Central Asia
title_fullStr How to Deal With Multi-Proxy Data for Paleoenvironmental Reconstructions: Applications to a Holocene Lake Sediment Record From the Tian Shan, Central Asia
title_full_unstemmed How to Deal With Multi-Proxy Data for Paleoenvironmental Reconstructions: Applications to a Holocene Lake Sediment Record From the Tian Shan, Central Asia
title_sort how to deal with multi-proxy data for paleoenvironmental reconstructions: applications to a holocene lake sediment record from the tian shan, central asia
publisher Frontiers Media S.A.
series Frontiers in Earth Science
issn 2296-6463
publishDate 2020-09-01
description Multi-proxy investigations on geological archives provide valuable information about environmental variations in the past. As opposed to single-proxy studies, the combination of several proxies can reveal more detailed information and strengthen subsequent paleoenvironmental reconstructions. However, there is still no consensus about how to deal with resulting highly dimensional datasets in a statistical manner. In many cases, the interpretations of multi-proxy datasets rely on visually matching several proxy records, which can lead to incorrect or insufficient interpretations. Here we report an innovative approach that combines the novel dimension reduction technique Uniform Manifold Approximation and Projection (UMAP) and the time series analysis R package asdetect to identify and characterize Holocene environmental phases and phase boundaries in a sediment core from Lake Chatyr Kol, southern Kyrgyzstan. Despite the fact that the Holocene climate evolution of Central Asia has been intensively studied during the last decades, knowledge about regional climate development during the Holocene and the underlying mechanisms is still relatively scarce. We particularly focus on phase transitions and differentiate between event-based shifts as opposed to gradual phase transitions. For this study, long-chain alkenones were used as a paleotemperature proxy and variations in long-chain alkyl diol distributions were ascribed to relative changes of algal input. The compound-specific stable hydrogen isotope compositions (δD) of individual n-alkanes were utilized as paleohydrological proxies, with the δD of mid-chain n-alkanes reflecting changes in the δD of the lake water and the δD of long-chain n-alkanes recording the δD of the meteoric water. We show the potential of modern analysis tools for data-driven paleoenvironmental reconstructions and advocate for their more frequent implementation in multi-proxy studies.
topic paleoenvironment
climate reconstructions
biomarkers
lake sediments
central asia
multi-proxy data
url https://www.frontiersin.org/article/10.3389/feart.2020.00353/full
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