C-Streams – The Gulf Stream control of the North Atlantic carbon sink

The joint UK-US C-Streams project will shed new light on the role of the Gulf Stream and North Atlantic in the global carbon cycle.

The Ocean takes up about 25% of the carbon dioxide (CO2) we emit to the atmosphere, slowing climate change, however, this sink is changing, having approximately doubled in size in the last 20 years, and has a highly uncertain response to net zero emissions. The North Atlantic is disproportionately important for anthropogenic carbon uptake and also hosts a very large ‘natural’ carbon cycle driven by both biological and physical processes. For these reasons understanding the Ocean carbon cycle in general, both now and how it will change going forward, and the North Atlantic carbon cycle specifically is a high-priority activity

C-Streams will focus on the role of the Gulf Stream, a key component of the North Atlantic circulation involved in driving this uptake. The Gulf Stream injects old nutrient-rich and anthropogenic carbon-poor waters into the North Atlantic, driving some of the highest rates of CO2 uptake seen anywhere in the ocean and shaping patterns of CO2 uptake across much of the subpolar and subtropical gyres. C-Streams will quantify and understand the source waters that feed the Gulf Stream at Florida Straits, measure and understand the processes that modify the nutrients and carbon carried by the Gulf Stream as it enters the North Atlantic, and then use this understanding in combination with numerical models to assess how the Gulf Stream affects North Atlantic carbon uptake now and into the future. We will deliver this new understanding directly to the international fora involved in driving forward the next generation of measurements of the ocean CO2 sink and managing our response to climate change.

C-Streams is a joint UKRI-NERC – NSF Large Grant funded from 2022–2027