Geochemical markers of the North Flinders Reef (Coral Sea, Australia) Porites sp. coral cores

Full description

North Flinders Reef in the Coral Sea (Australia) is located 150 km east of the Great Barrier Reef. A 3 m-long core of Porites sp. coral was extracted from the southern section of North Flinders reef in May 1992 (FLI01A) from approximately 5 to 10 m water depth by the Australian Institute of Marine Science (AIMS) using a hydraulic drill system. On the same trip, a long core (FLI02A) was extracted from the northwestern side of the reef. Once retrieved, the cores were rinsed with freshwater, sun-dried and stored on board the research vessel before sectioning at the Australian Institute of Marine Science, before being cut lengthwise into 7 mm thick slices and X-rayed to reveal regular and well-defined annual density bands.


In December 2017 a 0.5 m-long core (FLI05A) from 5 m water depth by a team of divers from James Cook University (Australia) and the University of Western Australia using a pneumatic air drilling system during a research cruise with MV Phoenix. All cores are stored in the core depository of at AIMS.


The geochemical markers in yearly growth layers of the coral cores were ingestigated to define changes in temperature, water chemistry, chemicals from pollution and fertilisers, and other anthropogenic influences. Sample analyses included Radiocarbon (14C), Radiogenic isotopes (137Cs, 210Pb, 241Am, 239+240Pu), Spheroidal carbonaceous fly-ash particles (SCP), Pollution metal (Hg), Coral skeleton-bound stable nitrogen isotopes (CS-δ15N), Stable oxygen and carbon isotopes ( δ18O, δ13C), and Trace elements (Sr/Ca, Mg/Ca, Ba/Ca).


Cores FLI01A and FLI05A were resampled in this study (see Zinke, et al. 2023) to annual resolution for the post-1940 period taking splits of the bimonthly samples for each individual year to obtain an annual sample of approx. 20–50 mg (FLI01A: 1940–1992 CE; FLI05A: 1988–2017 CE).

Lineage

Maintenance and Update Frequency: asNeeded

Statement: Coral cores were cut lengthwise into 7-mm-thick slices and X-rayed to reveal annual density bands used to establish the coral chronology. Yearly chronologies were established by X-ray based densitometry at AIMS following the method of Cantin and Lough (2014). Samples were milled in continuous 5-year intervals down the full length of the core along major coral growth axes, with some sections sampled at high resolution (every 1 mm, better than monthly resolution). Full sampling methodology can be found in the following articles/supplementary information to: FLI01A & FLI05A - Zinke, J., et al. (2023). North Flinders Reef (Coral Sea, Australia) Porites sp. corals as a candidate Global boundary Stratotype Section and Point for the Anthropocene series. The Anthropocene Review, 10(1), 201–224. https://doi.org/10.1177/20530196221142963 FLI02A - Calvo, E., et al. (2007). Interdecadal climate variability in the Coral Sea since 1708 A.D. Palaeogeography, Palaeoclimatology, Palaeoecology, 248(1), 190–201. https://doi.org/10.1016/j.palaeo.2006.12.003 and; Pelejero, C., et al. (2005). Preindustrial to Modern Interdecadal Variability in Coral Reef pH. Science, 309(5744), 2204–2207. https://doi.org/10.1126/science.1113692

Notes

Credit
Cantin, N. Australian Institute of Marine Science (AIMS)

Credit
Lough, J. (AIMS)