title: Coral luminescence identifies the Pacific Decadal Oscillation as a primary driver of river runoff variability impacting the southern Great Barrier Reef.
abstract: The Pacific Decadal Oscillation (PDO) is a large-scale climatic phenomenon modulating ocean-atmosphere variability on decadal time scales. While precipitation and river flow variability in the Great Barrier Reef (GBR) catchments are sensitive to PDO phases, the extent to which the PDO influences coral reefs is poorly understood. Here, six Porites coral cores were used to produce a composite record of coral luminescence variability (runoff proxy) and identify drivers of terrestrial influence on the Keppel reefs, southern GBR. We found that coral skeletal luminescence effectively captured seasonal, inter-annual and decadal variability of river discharge and rainfall from the Fitzroy River catchment. Most importantly, although the influence of El Niño-Southern Oscillation (ENSO) events was evident in the luminescence records, the variability in the coral luminescence composite record was significantly explained by the PDO. Negative luminescence anomalies (reduced runoff) were associated with El Niño years during positive PDO phases while positive luminescence anomalies (increased runoff) coincided with strong/moderate La Niña years during negative PDO phases. This study provides clear evidence that not only ENSO but also the PDO have significantly affected runoff regimes at the Keppel reefs for at least a century, and suggests that upcoming hydrological disturbances and ecological responses in the southern GBR region will be mediated by the future evolution of these sources of climate variability.
authors.affiliation: Radiogenic Isotope Facility, School of Earth Sciences, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Alberto
authors.initials: A
authors.lastname: Rodriguez-Ramirez
authors.affiliation: NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Geology, Den Burg, Texel, The Netherlands.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Grove
authors.affiliation: School of Earth and Environment, The University of Western Australia and the UWA Oceans Institute, Australia and the Australian Institute of Marine Science, Perth, Western Australia, Australia.
authors.forename: Jens
authors.initials: J
authors.lastname: Zinke
authors.affiliation: Australian Research Council Centre of Excellence for Coral Reef Studies, Centre for Marine Science, School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: John M
authors.initials: JM
authors.lastname: Pandolfi
authors.affiliation: Radiogenic Isotope Facility, School of Earth Sciences, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Jian-xin
authors.initials: JX
authors.lastname: Zhao
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000502:physiology*; D057894:Coral Reefs; D005843:Geography; D062312:Islands; D016014:Linear Models; D049449:Luminescence; D010140:Pacific Ocean; D045483:Rivers / Q000737:chemistry*; D012621:Seasons; D013057:Spectrum Analysis; D013997:Time Factors; D014872:Water Movements