The role of a changing Arctic Ocean and climate for the biogeochemical cycling of dimethyl sulphide and carbon monoxide

Abstract

Dimethyl sulphide (DMS) and carbon monoxide (CO) are climate-relevant trace gases that play key roles in the radiative budget of the Arctic atmosphere. Under global warming, Arctic sea ice retreats at an unprecedented rate, altering light penetration and biological communities, and potentially affect DMS and CO cycling in the Arctic Ocean. This could have socio-economic implications in and beyond the Arctic region. However, little is known about CO production pathways and emissions in this region and the future development of DMS and CO cycling. Here we summarize the current understanding and assess potential future changes of DMS and CO cycling in relation to changes in sea ice coverage, light penetration, bacterial and microalgal communities, pH and physical properties. We suggest that production of DMS and CO might increase with ice melting, increasing light availability and shifting phytoplankton community. Among others, policy measures should facilitate large-scale process studies, coordinated long term observations and modelling efforts to improve our current understanding of the cycling and emissions of DMS and CO in the Arctic Ocean and of global consequences.

Keywords: Arctic Ocean; Carbon monoxide; Climate; Dimethyl sulphide; Ice loss; Trace gases.

Fig. 1

Schematic view of the interactions of DMS and CO production, consumption and emission pathways in a changing Arctic Ocean. The dashed box marks the processes discussed in this article, comprising interactions in the ocean, ice and atmosphere. Thick arrows outside and towards the box represent changes in nutrients, salinity or pH due to increased ice melt (left side) and/or increased material input from land (right side). Those potentially alter ice-associated and pelagic DMS and CO processes and thus emissions in an uncertain way