التفاصيل البيبلوغرافية
| العنوان: |
The influence of iron and light on net community production in the Subantarctic and Polar Frontal Zones. |
| المؤلفون: |
Cassar, N., DiFiore, P. J., Barnett, B. A., Bender, M. L., Bowie, A. R., Tilbrook, B., Petrou, K., Westwood, K. J., Wright, S. W., Lefevre, D. |
| المصدر: |
Biogeosciences Discussions; 2010, Vol. 7 Issue 4, preceding p5649-5674, 35p, 2 Graphs |
| مصطلحات موضوعية: |
PRIMARY productivity (Biology), IRON, LIGHT, CARBON |
| مصطلحات جغرافية: |
ANTARCTIC Ocean |
| مستخلص: |
The roles of iron and light in controlling biomass and primary productivity are clearly established in the Southern Ocean. However, their influence on net community production (NCP) and carbon export remains to be quantified. To improve our understanding of NCP and carbon export production in the Subantarctic Zone (SAZ) and the northern reaches of the Polar Frontal Zone (PFZ), we conducted continuous onboard determinations of NCP as part of the Sub-Antarctic Sensitivity to Environmental Change (SAZ-Sense) study, which occurred in January-February 2007. Biological O2 supersaturation was derived from measuring O2/Ar ratios by equilibrator inlet mass spectrometry. Based on these continuous measurements, NCP during the austral summer 2007 in the Australian SAZ was approximately 43 mmolO2 m-2 d-1. Both gross primary productivity (estimated from the oxygen triple isotope anomaly) and NCP showed significant spatial variability, with larger values near the Subtropical front, and a general southward decrease. For shallower mixed layers (<50 m), dissolved Fe concentrations and Fe sufficiency, estimated from variable fluorescence, correlated strongly with NCP. At stations with deeper mixed layers, NCP was consistently low, regardless of iron sufficiency, consistent with light availability also being an important control of NCP. Our new observations provide independent evidence for the critical roles of iron and light in mediating carbon export from the Southern Ocean mixed layer. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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