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Influence of explicit Phaeocystis parameterizations on the global distribution of marine dimethyl sulfide
Author(s) -
Wang Shanlin,
Elliott Scott,
Maltrud Mathew,
CameronSmith Philip
Publication year - 2015
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1002/2015jg003017
Subject(s) - dimethyl sulfide , biogeochemical cycle , dimethylsulfoniopropionate , environmental science , marine ecosystem , phytoplankton , atmospheric sciences , oceanography , sulfur cycle , forcing (mathematics) , flux (metallurgy) , ecosystem , sea ice , cloud condensation nuclei , atmosphere (unit) , aerosol , climatology , radiative forcing , climate change , chemistry , sulfur , ecology , environmental chemistry , meteorology , geology , nutrient , geography , biology , organic chemistry
Abstract Dimethyl sulfide (DMS) is a biogenic organosulfur compound which contributes strongly to marine aerosol mass and the determination of cloud condensation nuclei over the remote oceans. Since uncertainties in DMS flux to the atmosphere lead to large variations in climate forcing, the global DMS distribution has been the subject of increasingly complex dynamic simulations. DMS concentrations are directly controlled by marine ecosystems. Phaeocystis is a major DMS producer but is often omitted from global reduced sulfur mechanisms. Here we incorporate this phytoplankton group into the marine ecosystem‐biogeochemical module of the Community Earth System Model. To examine its role in the ocean sulfur cycle, an earlier DMS model has been enhanced to include new knowledge gained over the last few years. Results from the baseline run show that simulated Phaeocystis biomass generally agrees with observations, with high concentrations near the Antarctic continent and between 50° and 60° north. Given the new explicit Phaeocystis representation, the DMS distribution shows significant improvements, especially regarding the amplitude and location of high‐latitude peaks. The simulated global mean surface DMS value is 2.26 n M , comparable to an estimate of 2.34 n M from the latest climatology extrapolated based on observations. The total oceanic DMS source to the atmosphere is 20.4 Tg S/yr, on the low side of previous estimates. Comparisons with and without Phaeocystis show that the group dominates DMS distributions in temperate and cold waters, contributing 13% of the global flux. The proportion may increase as sea ice declines and should be considered in climate projections.