Export and remineralization of POM in the Southern Ocean and the South China Sea estimated from ^210Po/^210Pb disequilibria

• Published in: Chinese science bulletin 2009-06, Vol.54 (12), p.2118-2123
• Main Authors: Yang, WeiFeng, Huang, YiPu, Chen, Min, Qiu, YuSheng, Peng, AnGuo, Zhang, Lei
• Format: Article
• Language: English
• Subjects: Articles/Oceanology; Chemistry/Food Science; Earth Sciences; Engineering; Humanities and Social Sciences; Life Sciences; multidisciplinary; Physics; Science; Science (multidisciplinary); 不平衡; 中国海; 再矿化; 南大洋; 海洋法; 聚甲醛
• ISSN: 1001-6538; 2095-9273; 1861-9541; 2095-9281
• DOI: 10.1007/s11434-009-0043-4

Disequilibria between ^210Po and ^210Pb in the upper water and their potential applications as a proxy of particle export and remineralization were examined in the Southern Ocean （station IV3） and the South China Sea （NS44）. ^210po was deficit in surface waters but excessive relative to ^210Pb in subsurface waters. Good positive correlation between ^210Po and particulate organic carbon （POC） indicated deficits and excess of ^210Po resulted from particulate organic matter （POM） export and remJneralization respectively, which was also supported by the decreased δ^13C and increased δ^15N downwards as a result of particle remineralization. On the basis of ^210Po/^210Pb box-model, POC export flux out of the surface waters were 1.2 mmol C. m^-2. d^-1 and 2.3 mmol C. m^-2. d^-1 for station NS44 and IV3, respectively. In the subsurface waters, remineralization fluxes of ^210Po were 0.062 Bq. m^-2.d^-1 and 0.566 Bq.m^-2.d^-1 for station NS44 and IV3 along with the recycle efficiency of 52±26% and 119±52%, respectively. Remineralized fluxes of POM derived from ^210Po and exported POC were 0.6 mmol C.m^-2.d^-1 and 2.7 mmol C. m^-2. d^-1 for NS44 and IV3. This study suggested that ^210Po was a powerful tracer of particle export and remineralization.