C-Streams-2024-Redeploy

C-Streams addresses a key knowledge gap regarding how carbon uptake over the North Atlantic is controlled by 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 is crucial for setting carbon dioxide uptake from the atmosphere. Working with US partners, we will measure the strength and variability of Gulf Stream property transports in Florida Straits. We will measure the downstream evolution of Gulf Stream nutrient and carbon concentrations over 2000 miles using targeted observations by autonomous instruments, novel analyses and model simulations. We will determine how the Gulf Stream provides a far field control of North Atlantic carbon uptake, providing an alternative paradigm to the prevailing view of control by stratification. We will then assess whether climate models provide the right response of the North Atlantic carbon sink to climate change and for the right reasons. We will deploy 3 moorings with biogeochemical instrumentation at 27 N in the Florida Straits - the same latitude as the NOAA WBTS repeat stations and the new NSF FOCUS array - to continuously measure property transports of the Gulf Stream over a two-year period. In particular, these moorings will resolve the nitrate and low-carbon transports of the relatively fresh deep waters in the Straits that originate in the southern hemisphere. It is hypothesized that northward advection of these waters fuels uptake of anthropogenic carbon in the North Atlantic. We will deploy gliders and Argo floats to quantify mixing and entrainment of these waters along their northward path in the Gulf Stream