南海表层沉积物与沉降颗粒物中有机碳的δ13C对比研究及其古环境再造意义

对南海表层沉积物与沉降颗粒物有机碳的δ13C进行了对比研究，从古环境再造方面探讨了陆源和海源对南海表层沉积物的贡献。南海表层沉积物有机碳的δ13C比沉降颗粒物中有机碳的δ13C偏重表明，Suess效应对南海现代过程的影响不可忽视，两者的δ13C差值反映了Suess效应对南海现代过程的影响程度。利用两者的δ13C差值，对现代陆源和海源有机碳的δ13C进行修正后，计算得到，在南海陆架周围表层沉积物的有机碳中，陆源的比例为48%，海源的比例为52%；在远离陆架的表层沉积物的有机碳中，陆源的比例为14%，海源的比例为86%。

Correlation of δ13 Corg in Surface Sediments with Sinking Particulate Matter in South China Sea and Implication for Reconstructing Paleo-environment

It has been observed that the Suess effect has influenced the isotopic composition of dissolved inorganic carbon in the sea.However,investigations for the Suess effect on the isotopic composition of organic carbon in the sea are rare.The South China Sea is one of the most important marginal sea in the world and the most crucial area in carbon budget in China Sea.Therefore,understanding the Suess effect occurring in the organic carbon is important for the carbon budget in the South China Sea.Here,the δ13Corg in surficial sediments and sinking particulate matter in South China Sea are reported to study the contribution for the surficial sediment organic material from terrestrial and marine.For marine sediments,the effect from selective degradation for the older sediments is larger than that for the younger one resulting in isotopic compostion of the former organic carbon lighter than the latter.However,the δ13Corg in surficial sediments is higher than that in particulate matter in our results,suggesting that Suess effect is innegligible for the modern process in South China Sea.The reason for this pattern might be that extensive burning of fossil fuels in recent years result in δ13C of atmospheric CO2 and dissolved inorganic carbon in seawater lighter,and then causing the δ13Corg in particulate matter lighter than that in surficial sediments.The difference in δ13Corg between surficial sediments and sinking particulate matter can show the effect that Suess effect exert to the modern progress in South China Sea.After using the difference in δ13Corg between surficial sediments and sinking particulate matter to amend the δ13Corg of terrestrial and marine,the contribution for the surficial sediment organic material from terrestrial is estimated to 48%,and from marine 52% on the adjacent inner shelf of South China Sea.In contrast,the contribution is estimated to 14% from terrestrial and 86% from marine beyond the inner shelf.This suggests the effects on the material input from rivers increase in the marginal sea with increasing human activities recently.This work expands our understanding of carbon isotope as biogeochemical tools for the Suess effect on the isotopic composition of organic carbon in the sea,emphasizing the role that the Suess effect may play in altering the isotopic composition of organic carbon in the sea.