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Reconstructing Past Sea Ice Cover With Coralline Red Algae.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Reconstructing Past Sea Ice Cover With Coralline Red Algae./
作者:	Leclerc, Natasha.
面頁冊數:	1 online resource (180 pages)
附註:	Source: Dissertations Abstracts International, Volume: 85-01, Section: B.
Contained By:	Dissertations Abstracts International85-01B.
標題:	Paleoclimate science. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29398846click for full text (PQDT)
ISBN:	9798379770235

Reconstructing Past Sea Ice Cover With Coralline Red Algae.
Leclerc, Natasha.

Reconstructing Past Sea Ice Cover With Coralline Red Algae. - 1 online resource (180 pages)

Source: Dissertations Abstracts International, Volume: 85-01, Section: B.

Thesis (Ph.D.)--University of Toronto (Canada), 2023.

Includes bibliographical references

Arctic sea ice plays a pivotal role in climate regulation. Its decline in recent decades has contributed to Arctic Amplification, the fast rate of Arctic warming in comparison to other regions. Models that aim to predict future climate are continuously under development as they still underestimate warming, and particularly sea ice loss and variability. These models must be refined with long-term, spatially diverse, and highly resolved data, to be as accurate as possible. However, instrumental data records are short-term and spatially constrained. The use and continued development of environmental proxies such as sediment and ice cores help lengthen data records (Chapter 1). Likewise, the coralline red algae species Clathromorphum compactum is a sea ice cover proxy in development. Several multi-century algal timeseries of past sea ice variability have been generated using this proxy, however, uncertainties remain about: 1) whether sea ice cover can be reconstructed at all C. compactum collection sites, and 2) whether methodological standardization ensure data replicability between intra-site specimens and validate C. compactum-based chronologies.In this thesis, I first tested whether growth increments, Mg/Ca averages, or combined anomalies were best suited to capture sea ice variability during the ~40-year satellite record at 11 subarctic and arctic sites (Chapter 2). Results showed that growth increment-based chronologies from exposed sites, far from runoff sources, experiencing long lasting sea ice cover (>6-7 months) best captured sea ice variability. However, intra-site replicability was low and insignificant at most sites in this multi-site study. This prompted a study on the application of dendrochronological crossdating methods to improve intra-site replicability of algal chronologies (Chapter 3). The findings suggested that the previously utilized methods incorporated subjective interpretation and that crossdating improved intra- and inter-specimen replicability, setting a new standardized methodology for age model determination and validation. Validated algal chronologies were then used to study the relationship between sea ice and large-scale atmospheric patterns and showed a significant sea ice response to the Arctic Oscillation and other atmospheric patterns (Chapter 4). This thesis has examined the advantages and limitations of the algal sea ice proxy and should methodologically guide future research with C. compactum-based proxies.

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

Mode of access: World Wide Web

ISBN: 9798379770235Subjects--Topical Terms:

3173835
Paleoclimate science.
Subjects--Index Terms:

Arctic sitesIndex Terms--Genre/Form:

542853
Electronic books.

Reconstructing Past Sea Ice Cover With Coralline Red Algae.
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520 $a Arctic sea ice plays a pivotal role in climate regulation. Its decline in recent decades has contributed to Arctic Amplification, the fast rate of Arctic warming in comparison to other regions. Models that aim to predict future climate are continuously under development as they still underestimate warming, and particularly sea ice loss and variability. These models must be refined with long-term, spatially diverse, and highly resolved data, to be as accurate as possible. However, instrumental data records are short-term and spatially constrained. The use and continued development of environmental proxies such as sediment and ice cores help lengthen data records (Chapter 1). Likewise, the coralline red algae species Clathromorphum compactum is a sea ice cover proxy in development. Several multi-century algal timeseries of past sea ice variability have been generated using this proxy, however, uncertainties remain about: 1) whether sea ice cover can be reconstructed at all C. compactum collection sites, and 2) whether methodological standardization ensure data replicability between intra-site specimens and validate C. compactum-based chronologies.In this thesis, I first tested whether growth increments, Mg/Ca averages, or combined anomalies were best suited to capture sea ice variability during the ~40-year satellite record at 11 subarctic and arctic sites (Chapter 2). Results showed that growth increment-based chronologies from exposed sites, far from runoff sources, experiencing long lasting sea ice cover (>6-7 months) best captured sea ice variability. However, intra-site replicability was low and insignificant at most sites in this multi-site study. This prompted a study on the application of dendrochronological crossdating methods to improve intra-site replicability of algal chronologies (Chapter 3). The findings suggested that the previously utilized methods incorporated subjective interpretation and that crossdating improved intra- and inter-specimen replicability, setting a new standardized methodology for age model determination and validation. Validated algal chronologies were then used to study the relationship between sea ice and large-scale atmospheric patterns and showed a significant sea ice response to the Arctic Oscillation and other atmospheric patterns (Chapter 4). This thesis has examined the advantages and limitations of the algal sea ice proxy and should methodologically guide future research with C. compactum-based proxies.
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653 $a Paleoclimate
653 $a Sea ice
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