Bridging International Activity and Related Research Into the Twilight Zone

The Twilight Zone spans from 100m to 1000m depth in the ocean. It is a region where very little light penetrates and where little is known about the processes that take place within it. Each year, nearly as much plant material is produced by microscopic plankton in the surface ocean as by all the land's forests and plains. Although created in the sunlit top 100m, this organic material eventually sinks, potentially taking a huge amount of carbon with it deep into the ocean interior where it could be trapped, away from the atmosphere, for up to hundreds of years. All but a few percent of this material is converted back into carbon dioxide within the Twilight Zone. To understand the role that marine life plays in regulating carbon dioxide in the atmosphere it is thus crucial to understand what controls this enormous recycling activity in the Twilight Zone.

UK projects addressing the Twilight Zone currently extend from the North Atlantic to the Southern Ocean. Simultaneously there are similar major current projects in the US and Spain with major projects being developed in France and Germany. Although each project tackles different aspects of the functioning of the Twilight Zone, by bringing them together a much more profound analysis is possible than by one alone. Working together there is an opportunity to revolutionise how we understand the functioning of the Twilight Zone.

BIARRITZ is funded by the NERC Global Partnership Seedcorn Fund to create something even greater than the sum of these already significant parts by using two linked approaches. It will provide fora for the projects; to meet, to share data, best practice and novel approaches, to pool data from the huge span of environments they encompass and to initiate collaborations to address gaps identified by this interaction. It will also take a lead to stimulate the necessary four types of collaboration, by initiating four small scale collaborations representing something old, something new, something borrowed and something out-of-the-blue.

The four seedcorn collaborations will be in conjunction with the NERC CUSTARD (https://roses.ac.uk/custard) project which, as part of the NERC Role of the Southern Ocean in the Earth System programme (RoSES – https://roses.ac.uk), is investigating how marine life, in the remote part of the Southern Ocean southeast of the Tierra del Fuego, influences the global carbon budget.