The production of volatile iodocarbons by biogenic marine aggregates
Hughes, C., G. Malin, C. M. Turley, B. J. Keely, P. D. Nightingale, and P. S. Liss
Limnol. Oceanogr., 53(2), 2008, 867–872

We present the first reported measurements of volatile iodocarbon production by biogenic marine aggregates. Iodomethane (CH₃I), iodoethane (C₂H₅I), 2-iodopropane (CH₃CHICH₃), and 1-iodopropane (CH₃CH₂CH₂I) concentrations were determined in incubations of aggregates formed by concentrating the >53 µm fraction of the plankton during a field campaign in the Celtic Sea. All four iodocarbons increased significantly in concentration in the aggregate incubations relative to filtered seawater controls. Maximum production rates ranged from 0.01 pmol L^-1 h^-1 for CH₃CHICH₃ to 0.31 pmol L^-1 h^-1 for C₂H₅I. Accompanying pheopigment and bacterial heterotrophic production suggest that the processes taking place on the aggregates studied were a good representation of those known to occur on natural marine particles. We also report iodocarbon production rates observed in natural marine aggregates, including a diatom mucilage collected in the Celtic Sea and phytodetritus sampled from Kongsfjord in the Arctic. Detrital particles could be hotspots of iodocarbon production in the marine environment.