Varying Biological Activity and Wind Stress Affect the DMS Response during the SAGE Iron Enrichment Experiment

Journal of Marine Science and Engineering

Simon Wright¹  Darren Fortescue²  Hilton Swan²  Stacey King²  Graham Jones²  Anke Schneider³  Mike Harvey⁴  Damien T Maher⁵ 

[1] Australian Antarctic Division and Antarctic Climate and Ecosystems CRC, Kingston, Tasmania 7050, Australia;Centre for Coastal Biogeochemistry, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia;Institute for Marine Chemistry, University of Oldenburg, 26122 Oldenburg, Germany;National Institute of Water and Atmospheric Research, Wellington 6241, New Zealand;Southern Cross Geoscience, Southern Cross University, Lismore, NSW 2480, Australia;

关键词: dimethylsulfide;    iron enrichment;    subantarctic;    microzooplankton grazing;   

DOI  :  10.3390/jmse8040268

来源: DOAJ

【 摘 要 】

Surface dissolved dimethylsulfide (DMS) and depth-integrated dimethylsulfoniopropionate (DMSP) measurements were made from March to April 2004 during the SOLAS Air–Sea Gas Exchange Experiment (SAGE) multiple iron enrichment experiment in subantarctic waters SE of New Zealand. During the first two iron enrichments, chl a and DMS production were constrained, but during the third enrichment, large pulses of DMS occurred in the fertilised IN patch, compared with the unfertilised OUT patch. During the third and fourth iron infusions, total chl a concentrations doubled from 0.52 to 1.02 µg/L. Hapto8s and prasinophytes accounted for 50%, and 20%, respectively, of total chl a. The large pulses of DMS during the third iron enrichment occurred during high dissolved DMSP concentrations and wind strength; changes in dinoflagellate, haptophyte, and cyanobacteria biomass; and increased microzooplankton grazing that exerted a top down control on phytoplankton production. A further fourth iron enrichment did cause surface waters to increase in DMS, but the effect was not as great as that recorded in the third enrichment. Differences in the biological response between SAGE and several other iron enrichment experiments were concluded to reflect microzooplankton grazing activities and the microbial loop dominance, resulting from mixing of the MLD during storm activity and high winds during iron enrichment.

【 授权许可】

Unknown