A time series of incubation experiments to examine the production and loss of CH3I in surface seawater

Shi, Qiang, Marandino, Christa, Petrick, Gert, Quack, Birgit and Wallace, Douglas W.R. (2014) A time series of incubation experiments to examine the production and loss of CH3I in surface seawater Journal of Geophysical Research - Oceans, 119 (12). pp. 8242-8254. DOI 10.1002/2014JC010223.

jgrc20973.pdf - Published Version

Download (1149Kb) | Preview

Supplementary data:


In order to investigate production pathways of methyl iodide and controls on emissions from the surface ocean, a set of repeated in vitro incubation experiments were performed over an annual cycle in the context of a time series of in situ measurements in Kiel Fjord (54.3°N, 10.1°E). The incubation experiments revealed a diurnal variation of methyl iodide in samples exposed to natural light, with maxima during day time and losses during night hours. The amplitude of the daily accumulation varied seasonally and was not affected by filtration (0.2 µm), consistent with a photochemical pathway for CH3I production. The methyl iodide loss rate at nighttime correlates with the concentration accumulated during daytime suggesting a first-order loss mechanism (R2 = 0.29, p << 0.01). Daily (24 h) net production (Pnet) was similar in magnitude between in vitro and in situ mass balances. However, the estimated gross production (Pgross) of methyl iodide ranged from −0.07 to 2.24 pmol L−1 d−1 and was up to 5 times higher in summer than Pnet calculated from the in situ study. The large excess of Pgross over Pnet in summer revealed by the incubation experiments is a consequence of large losses of CH3I by as-yet uncharacterized processes (e.g., biological degradation or chemical pathways other than Cl− substitution).

Document Type: Article
Additional Information: WOS:000348452800003
Keywords: methyl iodide; seawater; incubation experiments; mass balance
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-CH Chemical Oceanography
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
DOI etc.: 10.1002/2014JC010223
ISSN: 0148-0227
Projects: SOPRAN, Future Ocean
Date Deposited: 12 Jan 2015 07:03
Last Modified: 03 Jun 2015 23:38
URI: http://eprints.uni-kiel.de/id/eprint/26875

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...