SURFACE OCEAN RADIOCARBON FROM A <i>PORITES</i> CORAL RECORD IN THE GREAT BARRIER REEF: 1945–2017

ABSTRACT We present a high-resolution seawater radiocarbon (Δ 14 C) record from Porites coral collected Masthead Island in the southern Great Barrier Reef (GBR) covering years 1945–2017. The Δ C values 1945–1953 (pre-bomb era) averaged –49‰. As result of bomb-produced atmosphere, started to rise rapidly 1959, levelled off at ∼131‰ late 1970s and gradually decreased ∼40.3‰ by 2017 due decrease air-sea gradient overturning ocean reservoir (i.e., surface subsurface ocean; atmosphere ocean). is agreement with previous records GBR. A comparison between atmospheric suggests that, since 2010, main bomb-derived has shifted ocean, potentially resulting reversed flux regions where CO 2 favorable. sheds light on long-term variability exchange GBR regional dynamics associated climate change conjunction provides robust reference series date other carbonate samples.