Authors / CoAuthors
Huang, Z. | Feng, M. | Dalton, S. | Carroll, A.
Abstract
<div>The Great Barrier Reef (GBR) World Heritage Area and adjacent Coral Sea Marine Park are under serious threat from global climate change. This study used sea surface temperature (SST) data to identify major marine heatwaves (MHWs) occurring in this region over the last three decades (1992–2022) and to map significant MHW events that have occurred between 2015 and2022. We investigated the mechanisms of the MHWs and identified potential coral refugia. MHWs in this region have increased in frequency, intensity and spatial extent. El Niño, especially when it is in phase with positive Indian Ocean Dipole, was the key remote driver leading to intense MHWs. However, the more recent strong MHWs (e.g., 2017 and 2022) occurred without these climatic events, signifying the impacts of long-term climate change and local drivers. We also found that reduced wind speed and shoaling mixed layer depth, often together with reduced cloudiness, were the main local drivers pre-conditioning these MHWs. Anomalous air-sea heat flux into the ocean, mainly controlled by shortwave solar radiation (cloudiness) and latent heat flux (wind), was the most constant contributor to the 2015–16 and 2019–20 MHW events. However, local oceanographic dynamics, especially horizontal advection and turbulent mixing, played important roles in MHW heat budgets. This study confirmed that shallow-water coral bleaching severity was positively related to the cumulative MHW intensity in these two MHWs. We identified the shallow reefs along the path of the North Queensland Current as potential coral refugia from bleaching because of the cooler waters upwelled from the ocean current. We also found that, except during abnormal weather events such as tropical cyclones, the mesophotic reefs in the Coral Sea Marine Park may be less susceptible to severe bleaching as the MHWs are more confined within the shallow mixed layer.</div> Presented at the 30th Conference of the Australian Meteorological and Oceanographic Society (AMOS) 2024
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document
eCat Id
148705
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Keywords
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- Marine Heatwaves
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- MHW
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- Great Barrier Reef (GBR)
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- Coral Sea
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- Coral Bleaching
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- Mesophotic Reef
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- Himawari-8
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- Sea Surface Temperature (SST)
- theme.ANZRC Fields of Research.rdf
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- Environmental SciencesPhysical oceanographyClimate change science not elsewhere classified
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- Published_External
Publication Date
2024-08-01T03:30:29
Creation Date
2023-08-24T12:00:00
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completed
Purpose
This abstract is to be submitted to the 30th Australia Meteorological & Oceanographic Society (AMOS) Conference. The conference will be held in Canberra, 5-9 February 2024. If the abstract is accepted, I will give an oral presentation at a marine heatwaves (MHWs) special session. This talk will highlight the key findings of a collaborative study (with CSIRO) in MHWs, their mechanisms and their impact on shallow water and mesophotic reefs. This study used the data collected in the FK200802 survey (Seamount, Reefs and Canyons of the Coral Sea). This study is highly relevant to our marine geoscience works in terms of the sustainable management of Australia's marine jurisdiction.
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30th Conference of the Australian Meteorological and Oceanographic Society (AMOS) 5-9 February 2024, Canberra Australia Session 1. Beyond Temperature Extremes: Exploring the dynamics and impacts of marine heatwaves
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<div>The abstract is a result of the collaboration between Geoscience Australia and CSIRO. This study used many publicly available datasets. These included DOISST (NASA), Himawari-8 SST (JAXA), SSTAARS (Integrated Marine Observing System (IMOS)), BRAN2020 (CSIRO/National Computational Infrastructure in the Australian National University), eReefs (CSIRO), ERA5 (Copernicus Climate Change Service) and GBR coral bleaching data (James Cook University). The Conductivity Temperature Depth (CTD) and Autonomous Underwater Vehicle (AUV) data were collected during a Geoscience Australia led marine survey of the seamount, reefs and canyons of the Great Barrier Reef and Coral Sea Marine Parks (survey FK200802) on board R/V Falkor of the Schmidt Ocean Institute. The AUV data was collected by IMOS AUV <em>Sirius</em> operated by the Australian Centre for Field Robotics (University of Sydney).</div>
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[-54.75, -9.2402, 112.92, 159.11]
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