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.

A changing Arctic Ocean

“…They call for improved observational capabilities in the Arctic Ocean in order to reduce current emission estimates and strengthen the projections of future greenhouse gas emission trends within the context of global coupled models. Campen et al (2022) summarise the current understanding of dimethyl sulphide (DMS) and carbon monoxide (CO) sources and cycling in the Arctic. They demonstrate the interdependency and complexity of the ongoing changes in biogeochemical processes, and points to a potential increase of DMS and CO production with increasing ice melting, increasing light availability and shifting of phytoplankton communities due to climate change.…”

Nitrous oxide and methane in a changing Arctic Ocean

“…This “ocean methane paradox” has been explained in tropical and sub-tropical oligotrophic conditions by the decomposition of methylphosphonate in phosphorus starved conditions (Karl et al 2008 ) whereas in Arctic waters an alternative in situ CH 4 production has been proposed following the microbial cleavage of dimethylsulphoniopropionate (DMSP) (Damm et al 2008 , 2010 , 2015 ). Indeed DMSP is often found in very high concentrations in the AO during sea ice algal blooms and sea ice brines, and is projected to increase following ongoing changes to the Arctic environment (Campen et al 2021 ).…”

Variability of dimethyl sulphide (DMS), methanethiol and other trace gases in context of microbial communities from the temperate Atlantic to the Arctic Ocean

“…The bacterial families Rhodobacteraceae and Flavobacteriaceae are frequently abundant during phytoplankton blooms, contributing to the degradation of algal organic matter and the conversion of DMSP into DMS and MeSH (Moran et al, 2012;Moran and Durham, 2019). Campen et al, (2022) have recently emphasized the need to better link bacterial distribution with DMS and CO metabolism. In addition, the bacterial degradation of e.g.…”