Details

Autor(en) / Beteiligte

• Bailey, KE
• Najjar, R G
• Toole, DA
• Del Valle, DA
• Westby, G R
• Blomquist, B W
• Kieber, D J
• Kiene, R P
• Slezak, D
• Matrai, P A
• DiTullio, G

Titel

Diagnosis of Dimethylsulfide Production in Sargasso Sea Eddies

Ist Teil von

• Eos (Washington, D.C.), 2006-09, Vol.87 (36)

Erscheinungsjahr

2006

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• A Lagrangian time-series of dimethylsulfide (DMS) concentrations from a cyclonic and an anticyclonic eddy in the Sargasso Sea is used in conjunction with measured loss rates and a model of vertical mixing to estimate gross DMS production in the upper 60 m during the summer of 2004. The loss terms include biological consumption, photolysis, and ventilation to the atmosphere. Profiles of DMS and microbial DMS consumption rate constants were measured daily and ventilation was measured continuously using the eddy-correlation method. Photolysis rate constants were computed as a function of time and depth using an optical model constrained by apparent quantum yields calculated from in situ and deck incubations and forced with measurements of the light field and absorption by colored dissolved organic matter. Mixing is simulated with the K-Profile Parameterization model of Large et al. (1994), which accurately captures variability in sea surface temperature and mixed layer depth, indicating that the upper ocean mixing field is reasonably simulated. The mean profile of gross DMS production is surprisingly uniform in the upper 60 m, and there is no significant difference between the two eddies. The mean gross DMS production rate in the upper 60 m is estimated at 1.7 - 2.7 nM day super(-1) in the cyclonic eddy and 1.1 - 2.7 nM day super(-1) in the anticyclonic eddy. The net biological production rates (gross production minus microbial consumption) agree well with that diagnosed by Toole and Siegel (2004) in the mixed layer during the summer in the Sargasso Sea in the early 1990s. This suggests that the biomass weighted biological DMS production is extremely rapid in the summer, contributing to the observed summer paradox.