Ocean Deoxygenation Conference | Kiel 2018

Methane (CH4) is the most abundant hydrocarbon in the atmosphere and plays an important role in regulating the Earth's radiation balance and atmospheric chemistry in the troposphere. Coastal upwelling regions such as the eastern boundary upwelling systems and the Arabian Sea have been identified as sites of enhanced CH4 concentrations and emissions to the atmosphere. The coastal upwelling area off Peru is one of the most biologically productive regions of the world’s ocean connected to a large and persistent oxygen minimum zone (OMZ), but it is comparatively under-sampled and poorly understood in the context of trace gas cycling so far. From 2012 to 2017 we collected fifty-two depth profiles of dissolved CH4 during three cruises (M91, SO243, and M138) to the eastern tropical South Pacific Ocean off Peru. In this study, we present the inter-annual variations of the CH4 distributions in the water column off Peru, estimate the air-sea exchange from the upwelling region and decipher the influence of both the OMZ as well as the eddy structures on the CH4 pathways off Peru.