Our research group uses marine sediment records to reconstruct past environments, with an emphasis on changes in sea ice and associated changes in primary productivity. Our work is mainly focused in the Bering and Chukchi Seas. We apply a multiproxy approach to help untangle the story of ocean warming, declining sea ice extent and changing primary productivity in these regions during past intervals of climate warming. Some of the proxy tools that we use include:
- diatom assemblages
- foraminiferal oxygen isotopes
- sedimentary nitrogen and carbon isotopes
- grain size
- CT scanning
- proxy development
- age models
- past warm intervals
- laminated sediments
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Sea ice is a defining feature of our planet. It plays an important role in the global climate system, and serves as a habitat for some of the most spectacular animals on Earth—polar bears, walrus, and ice seals—as well as for some of the smallest primary producers: sea ice diatoms.
Arctic summer sea ice has declined at an alarming rate since satellites first began monitoring its extent in the late 1970s, and modelling results indicate that the Arctic Ocean may become ice free in the summer as early as 2030. Declining sea ice has the potential to further increase global temperatures through the ice-albedo feedback; because of this, it is critical to understand how sea ice will respond as temperatures rise. As Arctic sea ice continues to decline, another major concern is how this might affect biological productivity in the oceans. To address these questions, we study how sea ice and productivity changed in the past, during intervals when the earth warmed due to natural forcings. By examing the natural variability of sea ice, we can better understand the impacts of global change on future sea ice extent and sea ice-dependent ecosystems.