Nutrient availability determines dimethyl sulfide and isoprene distribution in the eastern Atlantic Ocean

Abstract

Continuous high-resolution underway measurements of dimethyl sulfide (DMS) and isoprene in the ocean surface were conducted from Germany to South Africa in November 2008. DMS, total dimethylsulfoniopropionate (DMSPt), isoprene and 19′-hexanoyloxyfucoxanthin (19′-hex) correlated in nitrogen-depleted regions when they were clustered by nitrogen to phosphorous ratio (N:P). The 19′-hex-containing algae groups might be a common source of DMS, DMSPt, and isoprene in the low N:P regions. Additionally, DMS and isoprene correlated in nitrate-depleted regions when they were clustered against nitrate concentrations. Correlations between DMS and isoprene were also found within nitrate-depleted eddies encountered along the cruise track. Eddies with N:P of ~2.8 showed the highest positive correlations between DMS and isoprene. We conclude that the DMS/isoprene relationships in the eastern Atlantic Ocean were influenced by nutrient availability, with implications for using nutrients to predict the DMS and isoprene concentrations over a range of oceanographic areas depleted in nitrogen. Key Points Nutrient availability (N:P) to characterize DMS and isoprene in Atlantic Ocean Mesoscale eddies have an effect on the DMS and isoprene distribution DMS and isoprene have common sources in the surface ocean © 2014. American Geophysical Union. All Rights Reserved.