Surface chlorophyll concentrations in relation to the Antarctic Polar Front: seasonal and spatial patterns from satellite observations
Moore, J.K.; Abbott, M.R. (2002). Surface chlorophyll concentrations in relation to the Antarctic Polar Front: seasonal and spatial patterns from satellite observations. J. Mar. Syst. 37(1-2): 69-86. http://dx.doi.org/10.1016/s0924-7963(02)00196-3
In: Journal of Marine Systems. Elsevier: Tokyo; Oxford; New York; Amsterdam. ISSN 0924-7963; e-ISSN 1879-1573, more
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| Keywords |
Algal blooms
Cycles > Chemical cycles > Geochemical cycle > Biogeochemical cycle > Nutrient cycles
Fronts > Atmospheric convergences > Polar fronts
Mesoscale features
Motion > Water motion > Vertical water movement > Upwelling
Organic compounds > Carbohydrates > Glycosides > Pigments > Photosynthetic pigments > Chlorophylls
Properties > Water properties > Temperature > Water temperature > Surface temperature
Remote sensing > Geosensing > Satellite sensing
Spatial variations
Temporal variations > Periodic variations > Seasonal variations
PSW, Antarctic Polar Front
Marine/Coastal |
| Author keywords |
phytoplankton; southern ocean; mesoscale |
| Abstract |
Satellite ocean color data from the Sea Viewing Wide Field of View Sensor (SeaWiFS) are used to investigate phytoplankton bloom dynamics at the Antarctic Polar Front (PF). Satellite sea surface temperature (SST) data are used to map the location of the PF at weekly timescales. Elevated chlorophyll within the PF often appears as a narrow band that occupies only a portion of the SST gradient across the PF. Phytoplankton blooms within the PF occur most frequently during the month of December and are unevenly distributed within the Southern Ocean. Elevated chlorophyll concentrations at the PF are most frequently observed where the current is interacting with large topographic features. Mesoscale physical processes, including meander-induced upwelling and increased eddy mixing, where the PF encounters large topographic features likely leads to increased nutrient flux to surface waters in these regions. The highest mean chlorophyll values associated with the PF occur where the front comes into contact with relatively shallow waters along the North Scotia Ridge and at Kerguelen Plateau. Iron input from sedimentary sources likely plays an important role in these regions. Over seasonal timescales it appears likely that light-limitation prevents phytoplankton blooms at the PF during winter and spring months. PF blooms are observed most commonly during December when surface radiation peaks and mixed layer depths are rapidly shoaling. Even during December, when the light regime would seem to be favorable, PF blooms are largely restricted to regions where enhanced nutrient fluxes to surface waters due to frontal dynamics are likely. During late summer, nutrient limitation due to depletion of iron and possibly silicate largely prevent blooms at the PF. In the fall, deepening mixed layers would provide some relief from nutrient limitation but likely lead again to light-limitation of growth rates and the prevention of blooms. |
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