Southern ocean contributions to glacial‐interglacial changes of atmospheric pCO2: An assessment of carbon isotope records in diatoms
Southern ocean contributions to glacial‐interglacial changes of atmospheric pCO2: An assessment of carbon isotope records in diatoms
复制标题
DOI：
10.1029/1999pa000369
复制
发表时间：
2000-02
期刊：
影响因子：
--
通讯作者：
Y. Rosenthal;M. Dahan;A. Shemesh
中科院分区：
文献类型：
--
作者：
Y. Rosenthal;M. Dahan;A. Shemesh
11个新的南极硅藻结合δ13Corg记录显示末次盛冰期的δ13Corg值明显低于全新世的δ13Corg值，并且在现代南极极锋（MAPF）向南的消耗增加的总体趋势。相比之下，来自MAPF更北的冰芯硅藻的δ13Corg值比全新世时期重约1‰。南极硅藻的低冰川δ13Corg的可能原因是较高的[CO2]aq，较低的生长速率以及硅藻丰度或大小的变化。从表面上看，δ13Corg的冰川消耗表明，在冰川期，MAPF以南的南极地表水可能是大气pCO2的一个来源。另外，冰川消耗可能是由于生长速率的相对较小的下降或两种优势硅藻物种的丰度或其平均细胞大小的变化引起的。对亚南极记录的解释也因类似的不确定性而变得复杂。
Eleven new Antarctic records of diatom-bound δ13Corg show significantly lighter values during the Last Glacial Maximum than during the Holocene with a general trend of increasing depletions southward of the modern Antarctic Polar Front (MAPF). In contrast, glacial diatoms from cores farther north of the MAPF show δ13Corg values which are ∼1‰ heavier than during the Holocene. Likely causes for the low glacial δ13Corg in Antarctic diatoms are higher [CO2]aq, lower growth rates, and changes in diatom abundance or size. Taken at face value, the glacial depletions of δ13Corg suggest that Antarctic surface waters south of the MAPF might have been a source of atmospheric pCO2 during the glacial period. Alternatively, the glacial depletions might have been caused by either a relatively small decrease in growth rates or changes in the abundance of the two dominant diatom species or their average cell size. Interpretations of the Subantarctic records are complicated by similar uncertainties.