Glacial-interglacial differences in carbonate burial in the equatorial Indian Ocean

To understand the variations in carbonate burial for the last 30 kiloannum (ka), we have utilized a core from the Ocean Drilling Program (ODP), Site716A (04.56 degrees N and 73.17 degrees E) retrieved from a water depth of 533 m from the Maldives (carbonate platform) Sea. We analysed calcium carbonate (CaCO3%), 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/CaCO3 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.

Automated summary

By analyzing samples from the Ocean Drilling Program in the Maldives, we found that carbonate preservation has declined in the last 30,000 years, possibly due to organic matter degradation in sediments. The ratio of C-org/CaCO3 was higher during the last glacial maximum, but lower during the last deglacial period and the Holocene. Additionally, heavier planktic foraminifera shell weights during the last deglacial period indicate increased carbonate preservation, which is linked to the release of carbon dioxide from the ocean to the atmosphere.