Calcium carbonate, sedimentary organic carbon, and shell weight of selected planktic foraminifera from ODP Hole 115-716A@en

To understand the variations in carbonate burial for the last 30 kiloannum (ka), we have utilized a core from the Ocean DrillingProgram (ODP), Site716A (04.56°N and 73.17°E) retrieved from a water depth of 533 m from the Maldives (carbonate platform) Sea. We analyzed calcium carbonate (CaCO%), sedimentary organic carbon (C-org %) and shell weights of selected planktic foraminifera species (Globigerinoides ruber, Pulleniatina obliquiloculata and Neogloboquadrina dutertrei) to see the contrast in carbonate preservation during the late last glacial-Holocene. Our dataset reveals that carbonate preservation declined during the last glacial maximum (LGM) and the Holocene, probably due to organic matter degradation in sediments. The ratio of C-org/CaCO was relatively higher during the LGM than during the last deglacial period (LDP) and the Holocene. Furthermore, the heavier planktic foraminifera shell weights during the LDP indicate relatively increased carbonate preservation, which is linked to the deglacial release of carbon dioxide (CO₂) from the ocean to the atmosphere.

为探究近30千年（ka）以来碳酸盐埋藏的变化规律，我们采用了取自马尔代夫（碳酸盐台地）海域、水深533米处的大洋钻探计划（Ocean Drilling Program, ODP）716A站位（04.56°N，73.17°E）的岩芯。我们针对选取的浮游有孔虫（planktic foraminifera）物种——红拟抱球虫（Globigerinoides ruber）、斜室普林虫（Pulleniatina obliquiloculata）与杜氏新单球虫（Neogloboquadrina dutertrei）——的壳体重量、碳酸钙（CaCO₃%）及沉积有机碳（C-org %）开展分析，以揭示末次冰期晚期-全新世时段内碳酸盐保存状况的差异。本数据集显示，末次盛冰期（Last Glacial Maximum, LGM）与全新世期间，碳酸盐保存能力均出现衰减，这一现象可能与沉积物中的有机质降解有关。末次盛冰期的C-org/CaCO₃比值相对高于末次冰消期（Last Deglacial Period, LDP）与全新世。此外，末次冰消期浮游有孔虫壳体重量偏大，反映当时碳酸盐保存能力相对提升，这与冰消期海洋向大气释放二氧化碳（CO₂）的过程存在关联。