Key Points:
Our overarching objective is to: Determine the role of the Gulf Stream in driving North Atlantic carbon uptake. This primary objective is broken up into three sub-objectives, each of which will be addressed via a dedicated Work Package: • O1. To determine the strength, variability and controls of the transport of nutrients and carbon at the start of the Gulf Stream, as the current exits the Florida Straits. • O2. To determine how processes occurring in the Gulf Stream along the US east coast affect the amount and location of nutrients and carbon injected into the subpolar North Atlantic. • O3. To determine how the nutrients and carbon injected into the subpolar North Atlantic by the Gulf Stream govern North Atlantic carbon uptake, and to assess how this uptake will change in the future. Objectives are sequential, with Objective 1 addressing the upstream conditions, Objective 2 addressing the property modifications along the Gulf Stream, and Objective 3 addressing the downstream consequences and future implications.
Overview: The ocean provides a crucial uptake of carbon from the atmosphere, acting to moderate the rise in atmospheric CO2 from carbon emissions. We will address a fundamental knowledge gap as to how the oceanic carbon sink will evolve in the future, by focussing on the mechanisms controlling the North Atlantic carbon sink – particularly the effect of ocean circulation. We are all aware that the Gulf Stream is important for heat supply to northern latitudes, but here we investigate how this current governs oceanic carbon uptake from the atmosphere. As a joint UK/US project, we will measure the strength and variability of Gulf Stream property transports in Florida Straits. We will assess the downstream evolution of evolving nutrient and carbon concentrations along 2000 miles of the length of the Gulf Stream using targeted observations from autonomous instruments, novel analytical techniques and model simulations. We will use high resolution models to determine how the Gulf Stream provides an advective control of North Atlantic carbon uptake, proposing and testing an alternative paradigm to the prevailing view of a local control by stratification. We will evaluate how the carbon sink varies in climate model projections (which by necessity are coarse resolution) and establish whether their responses are mechanistically sound using data collected in the project.
