Primary production across the Scotia Sea in relation to the physico-chemical environment

Korb, Rebecca E.; Whitehouse, M. J.; Thorpe, Sally; Gordon, Marina

doi:10.1016/j.jmarsys.2005.04.009

Cited by 60 publications

(62 citation statements)

References 51 publications

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“…In the Indian and Pacific sectors of the Southern Ocean, advection and water mass formation transmit a low CDOM signature to the deep ocean (Figures 2b and 2c), unlike the South Atlantic Ocean (Figure 2a). Satellite estimated primary production rates are substantially higher in the South Atlantic sector of the Southern Ocean than in the Pacific and Indian sectors covered in the present study [Arrigo et al, 2008], presumably caused by a release from iron limitation [Korb et al, 2005]. Patterns in the satellite retrieved CDOM are consistent with higher CDOM production in the South Atlantic sector of the Southern Ocean (Figure 1).…”

Section: Resultssupporting

confidence: 69%

Tracing global biogeochemical cycles and meridional overturning circulation using chromophoric dissolved organic matter

Nelson

Siegel

Carlson

et al. 2010

Geophysical Research Letters

144

142

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[1] Basin-scale distributions of light absorption by chromophoric dissolved organic matter (CDOM) are positively correlated (R 2 > 0.8) with apparent oxygen utilization (AOU) within the top kilometer of the Pacific and Indian Oceans. However, a much weaker correspondence is found for the Atlantic (R 2 < 0.05). Strong correlation between CDOM and AOU indicates that CDOM is created as a byproduct of the oxidation of organic matter from sinking particles. The observed meridional-depth sections of CDOM result from a balance between biogeochemical processes (autochthonous production and solar bleaching) and the meridional overturning circulation. Rapid mixing in the Atlantic dilutes CDOM in the interior and implies that the time scale for CDOM accumulation is greater than ∼50 years. CDOM emerges as a unique tracer for diagnosing changes in biogeochemistry and the overturning circulation, similar to dissolved oxygen, with the additional feature that it can be quantified from satellite observation.

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Section: Resultssupporting

confidence: 69%

Tracing global biogeochemical cycles and meridional overturning circulation using chromophoric dissolved organic matter

Nelson

Siegel

Carlson

et al. 2010

Geophysical Research Letters

144

142

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“…Naturally iron-fertilized systems usually present higher rates of primary production, e.g. up to ∼ 275 mmol C m −2 d −1 over the South Georgia plateau (Korb et al, 2005) and up to ∼ 250 mmol C m −2 d −1 within the fast-flowing, iron-rich jet of the polar front in the Atlantic sector (Jochem et al, 1995) and in the iron-fertilized plume of Crozet Islands . The production rates reported here for the fertilized areas (35 to 315 mmol C m −2 d −1 ) are in line with these previous studies ( Table 1), confirming that the spring phytoplankton blooms developing over, and downstream of the Kerguelen Plateau are sustained by very high rates of net primary production.…”

Section: High Primary Production In Naturally Iron-fertilized Bloomsmentioning

confidence: 99%

Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

et al. 2015

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Abstract. Although the Southern Ocean is considered a high-nutrient, low-chlorophyll (HNLC) area, massive and recurrent blooms are observed over and downstream of the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N uptake (NO − 3 and NH + 4 ), and nitrification rates were measured at eight stations in austral spring 2011 (October-November) during the KEOPS 2 cruise in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production, with mixed layer integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m −2 d −1 and up to 0.31 d −1 respectively) compared to the HNLC reference site (12 mmol C m −2 d −1 and 0.06 d −1 respectively). Primary production was mainly sustained by nitrate uptake, with f ratios (corresponding to NO − 3 -uptake / (NO − 3 -uptake + NH + 4 -uptake)) lying at the upper end of the observations for the Southern Ocean (up to 0.9). We report high rates of nitrification (up to ∼ 3 µmol N L −1 d −1 , with ∼ 90 % of them < 1 µmol N L −1 d −1 ) typically occurring below the euphotic zone, as classically observed in the global ocean. The specificity of the studied area is that at most of the stations, the euphotic layer was shallower than the mixed layer, implying that nitrifiers can efficiently compete with phytoplankton for the ammonium produced by remineralization at low-light intensities. Nitrate produced by nitrification in the mixed layer below the euphotic zone is easily supplied to the euphotic zone waters above, and nitrification sustained 70 ± 30 % of the nitrate uptake in the productive area above the Kerguelen Plateau. This complicates estimations of new production as potentially exportable production. We conclude that high productivity in deep mixing system stimulates the N cycle by increasing both assimilation and regeneration.

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“…CTD stations occupied along the transect line were part of the British Antarctic Survey's, Dipycnal and Isopycnal Mixing Experiment in the Scotia Sea (DIMES) project and are named according to their DIMES location starting with the most southerly station D1, up to the most northerly station, D34. For comparison, we also present data from an earlier, wider scale, Scotia Sea survey (cruise JR82, January 2003; Korb et al, 2005). Here we only included stations in close proximity (<150 km) to the 2008 transect line.…”

Section: Cruise Detailsmentioning

confidence: 99%

Summer microplankton community structure across the Scotia Sea: implications for biological carbon export

et al. 2010

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Abstract. During the austral summer of 2008, we carried out a high resolution survey of the microplankton communities along a south to north transect covering a range of environments across the Scotia Sea, Southern Ocean; high and low productivity, sea-ice to open water conditions, and over a number of oceanographic fronts and bathymetric features. Cluster analysis revealed five distinct communities that were geographically constrained by physical features of bathymetry and fronts. From south to north the communities were:

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Primary production across the Scotia Sea in relation to the physico-chemical environment

Cited by 60 publications

References 51 publications

Tracing global biogeochemical cycles and meridional overturning circulation using chromophoric dissolved organic matter

Tracing global biogeochemical cycles and meridional overturning circulation using chromophoric dissolved organic matter

Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

Summer microplankton community structure across the Scotia Sea: implications for biological carbon export

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