Eco-chemical mechanisms govern phytoplankton emissions of dimethylsulfide in global surface waters

Xuwei Deng; Jun Chen; Lars-Anders Hansson; Xia Zhao; Ping Xie

doi:10.1093/nsr/nwaa140

Eco-chemical mechanisms govern phytoplankton emissions of dimethylsulfide in global surface waters

Natl Sci Rev. 2020 Jun 23;8(2):nwaa140. doi: 10.1093/nsr/nwaa140. eCollection 2021 Feb.

Authors

Xuwei Deng¹, Jun Chen¹, Lars-Anders Hansson², Xia Zhao³, Ping Xie¹

Affiliations

¹ Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
² Department of Biology/Aquatic Ecology, Lund University, S-223 62 Lund, Sweden.
³ State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.

Abstract

The anti-greenhouse gas dimethylsulfide (DMS) is mainly emitted by algae and accounts for more than half of the total natural flux of gaseous sulfur to the atmosphere, strongly reducing the solar radiation and thereby the temperature on Earth. However, the relationship between phytoplankton biomass and DMS emissions is debated and inconclusive. Our study presents field observations from 100 freshwater lakes, in concert with data of global ocean DMS emissions, showing that DMS and algal biomass show a hump-shaped relationship, i.e. DMS emissions to the atmosphere increase up to a pH of about 8.1 but, at higher pH, DMS concentrations decline, likely mainly due to decomposition. Our findings from lake and ocean ecosystems worldwide were corroborated in experimental studies. This novel finding allows assessments of more accurate global patterns of DMS emissions and advances our knowledge on the negative feedback regulation of phytoplankton-driven DMS emissions on climate.

Keywords: biological regulation of global climate; dimethylsulfide; global surface oceans; lake ecosystem; phytoplankton.