 |
| Titel |
Wind-driven interannual variability of sea ice algal production in the western Arctic Chukchi Borderland |
| VerfasserIn |
E. Watanabe, J. Onodera, N. Harada, M. N. Aita, A. Ishida, M. J. Kishi |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 20 ; Nr. 12, no. 20 (2015-10-28), S.6147-6168 |
| Datensatznummer |
250118142
|
| Publikation (Nr.) |
 copernicus.org/bg-12-6147-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Seasonal and interannual variability in the biogenic particle sinking flux
was recorded using multi-year bottom-tethered sediment trap mooring systems
in the Northwind Abyssal Plain (Station NAP: 75° N, 162° W,
1975 m water depth) of the western Arctic Chukchi Borderland. Trapped
particle flux at a median depth of 184 m had an obvious peak and dominance
of sea ice-related diatom assemblages in August 2011. The observed particle
flux was considerably suppressed throughout summer 2012. In the present
study, the response of ice algal production and biomass to wind-driven
changes in the physical environment was addressed using a pan-Arctic sea
ice–ocean modeling approach. A sea ice ecosystem with ice algae was newly
incorporated into the lower-trophic marine ecosystem model, which was
previously coupled with a high-resolution (i.e., 5 km horizontal grid size)
sea ice–ocean general circulation model. Seasonal model experiments covering 2-year mooring periods indicated that primary productivity of ice algae
around the Chukchi Borderland depended on basin-scale wind patterns via
various processes. Easterly winds in the southern part of a distinct
Beaufort High supplied nutrient-rich water for euphotic zones of the NAP
region via both surface Ekman transport of Chukchi shelf water and vertical
turbulent mixing with underlying nutricline water in 2011. In contrast,
northwesterly winds flowing in the northern part of an extended Siberian
High transported oligotrophic water within the Beaufort Gyre circulation
toward the NAP region in 2012. The modeled ice algal biomass during summer
reflected the differences in nutrient distribution. The modeled sinking flux
of particulate organic nitrogen (PON) was comparable with the time series
obtained from sediment trap data in summer 2011. In contrast, lateral
advection of ice algal patches of shelf origin during a great cyclone event
may have caused a modeled PON flux bias in 2012. Sensitivity experiments
revealed several uncertainties of model configurations of ice algal
productivity, particle sinking speed, and grazing activities. Extending the
year-long measurements is expected to help illustrate the more general
features of ice-related biological processes in the Arctic Ocean. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|