Role of the Deglacial Buildup of the Great Barrier Reef for the Global Carbon Cycle

Abstract

The δ 13 C values of atmospheric carbon dioxide (CO 2 ) reconstructed from ice cores show that during the last deglaciation CO 2 with lower amounts of 13 C was released to the atmosphere in two rapid episodes (Bauska et al., 2016;Schmitt et al., 2012). In parallel to the onset of the deglacial CO 2 rise (Figure 1b) a prominent drop in the atmospheric δ 13 CO 2 values (Figure 1c) leading to a minimum centered at ∼16.0 ka is most commonly attributed to upwelling of old 13 C-depleted waters in the Southern Ocean (Köhler et al., 2005a;Menviel et al., 2018;Schmitt et al., 2012). However, the cause of a second prominent minimum in atmospheric δ 13 CO 2 centered at ∼12.4 ka during the Northern Hemisphere's Younger Dryas cold period (Figures 1a and 1c) that is synchronous to another period of CO 2 rise is not well understood (Bauska et al., 2016;Schmitt et al., 2012). Multi-proxy evidence invoke another pulse of Southern Ocean upwelling to explain these late deglacial carbon cycle changes (Anderson

Atmospheric CO2 Concentration Based on Boron Isotopes Versus Simulations of the Global Carbon Cycle During the Plio‐Pleistocene

“…Third (scenario SE+3), it was found that in the early part of the simulation window, when the sea level was primarily above the PI levels, the simulated mean ocean δ 13 C was consistently higher than the reconstructions (Figure S4c in Supporting Information ). It was found that the CaCO 3 accumulation in coral reefs, which was realized with an isotopic fractionation of −2‰ with respect to δ 13 C of DIC in the surface ocean (Felis et al., 2022; Linsley et al., 2019), was primarily responsible for this offset. In scenario SE+3, this δ 13 C mismatch was improved by restricting coral reef growth for higher than present day sea level to half its otherwise possible value.…”

Last Deglacial Environmental Change in the Tropical South Pacific From Tahiti Corals

“…The contribution of seawater δ 18 O to the coral skeletal δ 18 O signal (Δδ 18 O) can be derived from paired δ 18 O‐Sr/Ca analysis (Cahyarini et al., 2008). Coral δ 13 C is controlled by metabolic processes related to photosynthesis and respiration, kinetic effects related to calcification rate, and the state of the ambient seawater carbonate system (Felis et al, 2022; Linsley et al., 2019).…”