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Tessin core.JPG

Nansen Legacy Expedition to the Barents Sea- October 2018

Nutrient cycling within high latitude environments during past climate transitions

The Arctic Ocean is currently one of the most rapidly warming regions of the world. Changes occurring within the Arctic Ocean will have complex effects on nutrient availability and, subsequently, primary productivity. Different model scenarios for the biogeochemical response to anthropogenic climate change within the Arctic Ocean predict either elevated or reduced nutrient supplies, illustrating the need for improved constraints on how nutrient delivery and benthic remineralization will evolve under warmer conditions. The sedimentary record provides an opportunity to reconstruct biogeochemical cycles during past intervals of sea ice minima to help predict what may occur in the future.

This work is done through international collaborations with the Arctic in Rapid Transition early career network, the UK Changing Arctic Ocean Program and the Norwegian Nansen Legacy Program.

Research will continue on this theme will continue and focus on the Greenland margin during IODP Expedition 400.  



Modern benthic biogeochemistry


Sediments deposited at the bottom of lakes and oceans can act as sources or sinks of carbon, nutrients, and trace metals. Biogeochemical and early diagenetic processes control the release of these elements from the seafloor. By pairing sediment and porewater geochemistry, we can improve our understanding of nutrient recycling from the sediments to the overlying water column, as well as how environmental signals are preserved within the sedimentary record.


Current projects include work focused on the Barents Sea and on the Eurasian Arctic margin. This work includes collaborations with the UK National Environmental Research Council (NERC)-funded Changing Arctic Ocean Seafloor (ChAOS) project and the Norwegian Nansen Legacy project. 



Changing Arctic Ocean Seafloor Expedition - Summer 2017


Sampling of Lake Erie - Summer 2022



Other projects include research focusing on the impacts on harmful algal blooms within the Laurentide Great Lakes for lake bed methane production and nutrient remobilization. 


Core sampling at USGS core repository

Mechanisms of enhanced organic carbon burial during the Late Cretaceous

The Late Cretaceous was characterized by elevated pCO2 and an equable, warm climate, making it among the best examples of a greenhouse climate within the last 100 Ma of geologic history. During this time, a vast epicontinental seaway flooded the western interior of North America that extended from the Gulf Coast to the Arctic Ocean. The resulting sedimentary record of the Western Interior Seaway (WIS) includes episodic deposition of organic carbon-rich black shales, including during a series of Oceanic Anoxic Events (OAEs). Multiple processes control marine black shale deposition during OAEs, including changes in primary productivity, organic matter preservation, and sedimentary dilution. Much of our recent work has centered on sediments deposited within the WIS during a prolonged organic carbon burial event that has been identified as the Coniacian-Santonian OAE 3 (~88−84 Ma) to evaluate the relative roles of these forcing factors on marine carbon burial. 

 Ongoing work includes investigating changes in late Cretaceous carbon and iron cycling, as part of IODP Expedition 392 to the Agulhas Plateau. More details are available here.

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