 |
| Titel |
A survey of carbon monoxide and non-methane hydrocarbons in the Arctic Ocean during summer 2010 |
| VerfasserIn |
S. Tran, B. Bonsang, V. Gros, I. Peeken, R. Sarda-Estève, A. Bernhardt, S. Belviso |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 3 ; Nr. 10, no. 3 (2013-03-20), S.1909-1935 |
| Datensatznummer |
250018163
|
| Publikation (Nr.) |
 copernicus.org/bg-10-1909-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| During the ARK XXV 1 + 2 expedition in the Arctic Ocean
carried out in June–July 2010 aboard the R/V Polarstern, we measured carbon monoxide
(CO), non-methane hydrocarbons (NMHC) and phytoplankton pigments at the sea
surface and down to a depth of 100 m. The CO and NMHC sea-surface
concentrations were highly variable; CO, propene and isoprene levels ranged
from 0.6 to 17.5 nmol L−1, 1 to 322 pmol L−1 and
1 to 541 pmol L−1, respectively. The CO and alkene concentrations as well as their
sea–air fluxes were enhanced in polar waters off of Greenland, which were
more stratified because of ice melting and richer in chromophoric dissolved
organic matter (CDOM) than typical North Atlantic waters. The spatial
distribution of the surface concentrations of CO was consistent with our
current understanding of CO-induced UV photoproduction in the sea. The
vertical distributions of the CO and alkenes were comparable and followed
the trend of light penetration, with the concentrations displaying a
relatively regular exponential decrease down to non-measurable values below
50 m. However, no diurnal variations of CO or alkene concentrations were
observed in the stratified and irradiated surface layers. On several
occasions, we observed the existence of subsurface CO maxima at the level of
the deep chlorophyll maximum. This finding suggests the existence of a
non-photochemical CO production pathway, most likely of phytoplanktonic
origin. The corresponding production rates normalized to the chlorophyll
content were in the range of those estimated from laboratory experiments. In
general, the vertical distributions of isoprene followed that of the
phytoplankton biomass. These data support the existence of a dominant
photochemical source of CO and light alkenes enhanced in polar waters of the
Arctic Ocean, with a minor contribution of a biological source of CO. The
biological source of isoprene is observed in the different water masses but
significantly increases in the warmer Atlantic waters. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|