BiSS

Biogeochemical cycling on the Scotian Shelf – Impact of past and present climate change (BiSS)

High ecosystem productivity on the Scotian Shelf (northwestern Atlantic) is caused by mixing of contrasting water masses delivered by the Gulf Stream and the Labrador Current. However, a weakening of the Atlantic Meridional Overturning Circulation (AMOC) over the last decades has led to warming, deoxygenation and severe ecological changes. During research cruise MSM118 in 2023, sediment cores were retrieved in several Scotian Shelf basins and processed for pore water and particulate geochemical analyses. A preliminary assessment of the data suggests that lateral and temporal (since the last deglaciation) gradients in sedimentary nutrient and organic carbon turnover are closely coupled to water mass mixing as well as ocean circulation and climate change in the North Atlantic. Within the DFG-funded BiSS project, we intend to quantify and determine the controls on nutrient and organic carbon turnover along the Scotian Shelf by means of detailed biogeochemical analyses and numerical reaction-transport modeling. We further intend to reconstruct the evolution of biogeochemical cycling in shelf basins since the last deglaciation when sedimentation transitioned from semi-restricted basin conditions to modern open-marine conditions. By evaluating biogeochemical turnover in the sediments as a function of modern water mass characteristics, we will then aim to predict how biogeochemical cycling on the Scotian Shelf will respond to ongoing climate change. The results of the project will ultimately lead to a better understanding of how biogeochemical cycles at ocean margins will evolve in a future ocean.

Duration: 2025-2027

Funding source: DFG

Project partner: Dr. Andrew W. Dale, GEOMAR Helmholtz Centre for Ocean Research Kiel

Information about the project: Prof. Dr. Florian Scholz, Dr. Mark Zindorf