Multiproxy study of Holocene climatic and biogeochemical change in the Labrador Sea Region

Projet collaboratif du Geotop

2020-2022

The Arctic Ocean is highly sensitive to global climate change and is an important driver of climate feedback, both through changes in sea-ice cover (the ice-albedo feedback) and changes in the Atlantic Meridional Overturning Circulation (AMOC), which strongly controls global ocean circulation. Despite its importance, we have a poor understanding of how the Arctic Ocean region responds to climatic warming on centennial to millennial timescales. In particular, we do not understand how co-occurring changes in temperature and precipitation affect variables like sea-ice cover, freshwater runoff, and salinity, all of which are important factors modulating the climate feedbacks mentioned above. In addition, it is unclear how climatic change will influence biogeochemical cycling in sediments, which is important for the possible sequestration of carbon derived from both marine and terrestrial ecosystems in Arctic Ocean sediments.

To better understand possible future climate feedbacks in the Arctic Ocean, it is imperative to gain a better understanding of past climate variability. This is, however, challenging because many traditional climate proxies are unavailable in Arctic sediments, whereas other climate parameters (i.e. sea ice extent) have not had well defined climate proxies until recently. In this study, we plan to develop new multi-proxy climate records that will constrain changes in temperature, precipitation patterns, salinity, sea-ice extent, and carbon cycling in coastal sediments from the Labrador Sea since the last deglaciation. This study will take advantage of two key attributes of the Geotop researchers involved: 1) interdisciplinary expertise that will provide for analysis and interpretation of a wide range of geochemical, isotopic, and palynological proxies; 2) ready access to two Holocene sediment cores from the Labrador Sea with which we can begin analytical work immediately.