scholarly journals Plankton Assemblage Estimated with BGC-Argo Floats in the Southern Ocean: Implications for Seasonal Successions and Particle Export

2017 ◽  
Vol 122 (10) ◽  
pp. 8278-8292 ◽  
Author(s):  
Mathieu Rembauville ◽  
Nathan Briggs ◽  
Mathieu Ardyna ◽  
Julia Uitz ◽  
Philippe Catala ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Argo Floats ◽  
Particle Export

scholarly journals Eddies Observed by Argo Floats. Part II: Form Stress and Streamline Length in the Southern Ocean

2017 ◽  
Vol 47 (9) ◽  
pp. 2237-2250 ◽  
Author(s):  
Katsuro Katsumata
Keyword(s):  
Southern Ocean ◽  
Drake Passage ◽  
Meridional Transport ◽  
Argo Floats ◽  
Momentum Budget ◽  
Eddy Transport ◽  
Circumpolar Current ◽  
Topographic Barriers ◽  
The Antarctic ◽  
Zonal Momentum

AbstractArgo floats measure horizontal current velocities at the parking depth and vertical profiles of temperature and salinity. These data were used to study the roles that eddies play in the dynamics of the Antarctic Circumpolar Current (ACC) in the Southern Ocean. A zonal momentum budget was quantified in a box spanning the latitudes of the Drake Passage and bounded by the sea surface and the 1000-dbar depth. The input of eastward zonal momentum from the wind (17.1 × 1011 N) was approximately twice the downward transfer of eastward momentum across the isopycnal whose mean depth was 1000 dbar, which was mediated via form stress carried by eddies [(8.1 ± 1.9) × 1011 N]. The zonal momentum budget was closed to within uncertainty, meaning that the momentum not accounted for by eddies was explained by the Coriolis term associated with meridional transport. The form stress was spatially concentrated near meridional ridges, particularly on their eastern flanks. The localization was extreme: 7% of the total area contributed about 90% of the form stress. Lengths of streamlines were stretched around steady standing meanders. Seven major meanders were found at large topographic barriers along the ACC, with cyclonic meander collocated with the peaks of the topographic barriers. Eddies were found to lengthen the streamlines mostly on the eastern flanks of the meridional ridges, where the eddy transport was southward. Poleward eddy transport on the eastern flanks of meridional ridges is thus highlighted in the ACC dynamics in transferring eastward zonal momentum downward and in adjusting to wind changes by stretching streamlines.

scholarly journals Latitudinal and temporal distributions of diatom populations in the pelagic waters of the Subantarctic and Polar Frontal Zones of the Southern Ocean and their role in the biological pump

2015 ◽  
Vol 12 (11) ◽  
pp. 8615-8690 ◽  
Author(s):  
A. S. Rigual-Hernández ◽  
T. W. Trull ◽  
S. G. Bray ◽  
A. Cortina ◽  
L. K. Armand
Keyword(s):  
Southern Ocean ◽  
Biogenic Silica ◽  
Large Fraction ◽  
Sediment Traps ◽  
Strong Positive Correlation ◽  
Carbon Export ◽  
Relative Contribution ◽  
Frontal Zones ◽  
Particle Fluxes ◽  
Particle Export

Abstract. The Subantarctic and Polar Frontal zones (SAZ and PFZ) represent a large portion of the total area of the Southern Ocean and serve as a strong sink for atmospheric CO2. These regions are central to hypotheses linking particle fluxes and climate change, yet multi-year records of modern flux and the organisms that control it are, for obvious reasons, rare. In this study, we examine two sediment trap records of the flux of diatoms and bulk components collected by two bottom-tethered sediment traps deployed at mesopelagic depths (~ 1 km) in the SAZ (two-year record) and in the PFZ (six-year record) along the 140° E meridian. These traps provide a direct measure of transfer below winter mixed layer depths, i.e. at depths where effective sequestration from the atmosphere occurs, in contrast to study of processes in the surface ocean. Total mass fluxes were about two-fold higher in the PFZ (24 ± 13 g m−2 yr−1) than in the SAZ (14 ± 2 g m−2 yr−1). Bulk chemical composition of the particle fluxes mirrored the composition of the distinct plankton communities of the surface layer, being dominated by carbonate in the SAZ and by biogenic silica in the PFZ. POC export was similar for the annual average at both sites (1.0 ± 0.1 and 0.8 ± 0.4 g m−2 yr−1, for the PFZ and SAZ, respectively), indicating that the particles in the SAZ were relatively POC rich. Seasonality in the particle export was more pronounced in the PFZ. Peak fluxes occurred during summer in the PFZ and during spring in the SAZ. The strong summer pulses in the PFZ are responsible for a large fraction of the variability in carbon sequestration from the atmosphere in this region. The latitudinal variation of the total diatom flux was found to be in line with the biogenic silica export with an annual flux of 31 ± 5.5 × 108 valves m−2 yr−1 at the PFZ compared to 0.5 ± 0.4 × 108 m−2 yr−1 of the SAZ. Fragilariopsis kerguelensis dominated the annual diatom export at both sites (43 at the SAZ and 59% in the PFZ). POC fluxes displayed a strong positive correlation with the relative contribution of a group of weakly-silicified and bloom-forming species in the PFZ. Several lines of evidence suggest that the development of these species during the growth season facilitates the formation of aggregates and carbon export. Our results confirm previous work suggesting that F. kerguelensis is a major aspect of the decoupling of the carbon and silicon cycles in the high-nutrient low-chlorophyll waters of the Southern Ocean.

scholarly journals Oxygen in the Southern Ocean From Argo Floats: Determination of Processes Driving Air-Sea Fluxes

2017 ◽  
Vol 122 (11) ◽  
pp. 8661-8682 ◽  
Author(s):  
Seth M. Bushinsky ◽  
Alison R. Gray ◽  
Kenneth S. Johnson ◽  
Jorge L. Sarmiento
Keyword(s):  
Southern Ocean ◽  
Argo Floats

scholarly journals 234Th deficit and excess in the Southern Ocean during spring 2001: Particle export and remineralization

2004 ◽  
Vol 31 (12) ◽  
pp. n/a-n/a ◽  
Author(s):  
N. Savoye ◽  
K. O. Buesseler ◽  
D. Cardinal ◽  
F. Dehairs
Keyword(s):  
Southern Ocean ◽  
Particle Export

scholarly journals Particle export during the Southern Ocean Iron Experiment (SOFeX)

2005 ◽  
Vol 50 (1) ◽  
pp. 311-327 ◽  
Author(s):  
K. O. Buesseler ◽  
J. E. Andrews ◽  
S. M. Pike ◽  
M. A. Charette ◽  
L. E. Goldson ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Particle Export

scholarly journals Latitudinal and temporal distributions of diatom populations in the pelagic waters of the Subantarctic and Polar Frontal zones of the Southern Ocean and their role in the biological pump

2015 ◽  
Vol 12 (18) ◽  
pp. 5309-5337 ◽  
Author(s):  
A. S. Rigual-Hernández ◽  
T. W. Trull ◽  
S. G. Bray ◽  
A. Cortina ◽  
L. K. Armand
Keyword(s):  
Southern Ocean ◽  
Biogenic Silica ◽  
Large Fraction ◽  
Sediment Traps ◽  
Strong Positive Correlation ◽  
Carbon Export ◽  
Relative Contribution ◽  
Frontal Zones ◽  
Particle Fluxes ◽  
Particle Export

Abstract. The Subantarctic and Polar Frontal zones (SAZ and PFZ) represent a large portion of the total area of the Southern Ocean and serve as a strong sink for atmospheric CO2. These regions are central to hypotheses linking particle fluxes and climate change, yet multi-year records of modern flux and the organisms that control it are, for obvious reasons, rare. In this study, we examine two sediment trap records of the flux of diatoms and bulk components collected by two bottom-tethered sediment traps deployed at mesopelagic depths (~ 1 km) in the SAZ (2-year record; July 1999–October 2001) and in the PFZ (6-year record; September 1997–February 1998, July 1999–August 2000, November 2002–October 2004 and December 2005–October 2007) along the 140° E meridian. These traps provide a direct measure of transfer below winter mixed layer depths, i.e. at depths where effective sequestration from the atmosphere occurs, in contrast to study of processes in the surface ocean. Total mass fluxes were about twofold higher in the PFZ (24 ± 13 g m−2 yr−1) than in the SAZ (14 ± 2 g m−2 yr−1). Bulk chemical composition of the particle fluxes mirrored the composition of the distinct plankton communities of the surface layer, being dominated by carbonate in the SAZ and by biogenic silica in the PFZ. Particulate organic carbon (POC) export was similar for the annual average at both sites (1.0 ± 0.1 and 0.8 ± 0.4 g m−2 yr−1 for the PFZ and SAZ, respectively), indicating that the particles in the SAZ were relatively POC rich. Seasonality in the particle export was more pronounced in the PFZ. Peak fluxes occurred during summer in the PFZ and during spring in the SAZ. The strong summer pulses in the PFZ are responsible for a large fraction of the variability in carbon sequestration from the atmosphere in this region. The latitudinal variation of the total diatom flux was found to be in line with the biogenic silica export with an annual flux of 31 ± 5.5 × 108 valves m−2 yr−1 at the PFZ compared to 0.5 ± 0.4 × 108 m−2 yr−1 at the SAZ. Fragilariopsis kerguelensis dominated the annual diatom export at both sites (43 % at the SAZ and 59 % in the PFZ). POC fluxes displayed a strong positive correlation with the relative contribution of a group of weakly silicified and bloom-forming species in the PFZ. Several lines of evidence suggests that the development of these species during the growth season facilitates the formation of aggregates and carbon export. Our results confirm previous work suggesting that F. kerguelensis plays a major role in the decoupling of the carbon and silicon cycles in the high-nutrient low-chlorophyll waters of the Southern Ocean.

scholarly journals Water Masses and Flow Fields of the Southern Ocean Measured by Autonomous Profiling Floats (Argo floats)

2005 ◽  
Vol 27 (2) ◽  
pp. 183-188
Author(s):  
Young-Gyu Park ◽  
Kyung-Hee Oh ◽  
Moon-Sik Suk
Keyword(s):  
Southern Ocean ◽  
Flow Fields ◽  
Water Masses ◽  
Argo Floats

scholarly journals Evaluating Southern Ocean Carbon Eddy-Pump From Biogeochemical-Argo Floats

2018 ◽  
Vol 123 (2) ◽  
pp. 971-984 ◽  
Author(s):  
Joan Llort ◽  
C. Langlais ◽  
R. Matear ◽  
S. Moreau ◽  
A. Lenton ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Argo Floats ◽  
Ocean Carbon

Particle export and the biological pump in the Southern Ocean

2004 ◽  
Vol 16 (4) ◽  
pp. 501-516 ◽  
Author(s):  
SUSUMU HONJO
Keyword(s):  
Organic Carbon ◽  
Southern Ocean ◽  
Carbon Particle ◽  
Polar Front ◽  
Antarctic Polar Front ◽  
Biological Pump ◽  
The South ◽  
Regeneration Rate ◽  
Particle Export ◽  
The Antarctic

The organic carbon particle export to the interior layers in the Southern Ocean in the New Zealand–Tasmania Sector was approximately 170 mmolC m−2 yr−1. The export of particulate inorganic carbon in CaCO3 was 110 mmolC m−2 yr−1 and was contributed mostly by pteropods shells in the Antarctic Zones. The Si flux from biogenic opal at the sub-Antarctic Zone was 67 mmolSi m−2 yr−1 and rapidly increased to the south up to nearly 1 molSi m−2 yr−1 in the Antarctic Zone. The Antarctic Polar Front clearly demarcated the area where the biological pump was driven by CaCO3 to the north and biogenic SiO2 particle export to the south. Summer stratification caused by the sub-zero winter water layer in the Seasonal Ice Zone (SIZ) curtails the zooplankton community and hinders the replenishment of Fe. This hypothesis explains the large organic carbon export with large f- and export ratios at the SIZ and extremely large opal production at the Antarctic Circumpolar Zone. Estimated regeneration rate of CO2 from the export production and settling particulate fluxes of organic carbon in the water column between 100 m to 1 km was about 13 mmolC m−2 d−1 in the Antarctic Zone and Polar Frontal Zone.

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