Assessment of the impacts of rapid Marine Heatwaves and cumulative thermal stress on cold-water upwelling coral refugia

This study introduces a combined Marine Heatwaves-Degree Heating Weeks (MHW-DHW) analysis to evaluate climate change impacts on three coral refugia: Green Island, Nanwan Bay, and Dongsha Atoll. MHWs reflect rapid rises in Sea Surface Temperature (SST) and their timing, while DHW captures sustained h...

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Main Authors: Po-Chun Hsu, Rose Angeli Tabanao Macagga, Roshin P. Raj
Format: Article
Language:English
Published: Taylor & Francis Group 2025-12-01
Series:Geomatics, Natural Hazards & Risk
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Online Access:https://www.tandfonline.com/doi/10.1080/19475705.2024.2448240
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author Po-Chun Hsu
Rose Angeli Tabanao Macagga
Roshin P. Raj
author_facet Po-Chun Hsu
Rose Angeli Tabanao Macagga
Roshin P. Raj
author_sort Po-Chun Hsu
collection DOAJ
description This study introduces a combined Marine Heatwaves-Degree Heating Weeks (MHW-DHW) analysis to evaluate climate change impacts on three coral refugia: Green Island, Nanwan Bay, and Dongsha Atoll. MHWs reflect rapid rises in Sea Surface Temperature (SST) and their timing, while DHW captures sustained high SSTs, indicating thermal stress, potential bleaching risks, and vulnerability of coral habitats. Since 2016, rapid MHW development has significantly increased annual thermal stress. Between 2020 and 2022, nearly half of each year they faced MHW threats corresponding to Bleaching Alert Levels 2 and 3. Historically, bleaching events were linked to strong El Niño transitioning to strong La Niña conditions during the negative phase of the Pacific Decadal Oscillation; however, recent sustained global ocean warming has masked this pattern. Periodic cooling due to upwelling in these habitats is not fully captured by the CoralTemp dataset due to smoothing and low spatial resolution. CoralTemp SST values differ from Himawari satellite observations by about 1 to 1.4 °C in daily minima, leading to average SST discrepancies of 0.2–0.5 °C. This suggests diurnal temperature variations may still mitigate sustained high temperatures. Furthermore, multi-satellite data revealed that rapid MHW development has not significantly affected chlorophyll concentrations within coral habitats.
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series Geomatics, Natural Hazards & Risk
spelling doaj-art-d2cdbc03fe3b407f84036dbf46892b732025-08-20T02:26:15ZengTaylor & Francis GroupGeomatics, Natural Hazards & Risk1947-57051947-57132025-12-0116110.1080/19475705.2024.2448240Assessment of the impacts of rapid Marine Heatwaves and cumulative thermal stress on cold-water upwelling coral refugiaPo-Chun Hsu0Rose Angeli Tabanao Macagga1Roshin P. Raj2Center for Space and Remote Sensing Research, National Central University, Taoyuan City, TaiwanCenter for Space and Remote Sensing Research, National Central University, Taoyuan City, TaiwanNansen Environmental and Remote Sensing Center, Bergen, NorwayThis study introduces a combined Marine Heatwaves-Degree Heating Weeks (MHW-DHW) analysis to evaluate climate change impacts on three coral refugia: Green Island, Nanwan Bay, and Dongsha Atoll. MHWs reflect rapid rises in Sea Surface Temperature (SST) and their timing, while DHW captures sustained high SSTs, indicating thermal stress, potential bleaching risks, and vulnerability of coral habitats. Since 2016, rapid MHW development has significantly increased annual thermal stress. Between 2020 and 2022, nearly half of each year they faced MHW threats corresponding to Bleaching Alert Levels 2 and 3. Historically, bleaching events were linked to strong El Niño transitioning to strong La Niña conditions during the negative phase of the Pacific Decadal Oscillation; however, recent sustained global ocean warming has masked this pattern. Periodic cooling due to upwelling in these habitats is not fully captured by the CoralTemp dataset due to smoothing and low spatial resolution. CoralTemp SST values differ from Himawari satellite observations by about 1 to 1.4 °C in daily minima, leading to average SST discrepancies of 0.2–0.5 °C. This suggests diurnal temperature variations may still mitigate sustained high temperatures. Furthermore, multi-satellite data revealed that rapid MHW development has not significantly affected chlorophyll concentrations within coral habitats.https://www.tandfonline.com/doi/10.1080/19475705.2024.2448240Coral habitatupwellingocean warmingMarine HeatwaveDegree Heating Week
spellingShingle Po-Chun Hsu
Rose Angeli Tabanao Macagga
Roshin P. Raj
Assessment of the impacts of rapid Marine Heatwaves and cumulative thermal stress on cold-water upwelling coral refugia
Geomatics, Natural Hazards & Risk
Coral habitat
upwelling
ocean warming
Marine Heatwave
Degree Heating Week
title Assessment of the impacts of rapid Marine Heatwaves and cumulative thermal stress on cold-water upwelling coral refugia
title_full Assessment of the impacts of rapid Marine Heatwaves and cumulative thermal stress on cold-water upwelling coral refugia
title_fullStr Assessment of the impacts of rapid Marine Heatwaves and cumulative thermal stress on cold-water upwelling coral refugia
title_full_unstemmed Assessment of the impacts of rapid Marine Heatwaves and cumulative thermal stress on cold-water upwelling coral refugia
title_short Assessment of the impacts of rapid Marine Heatwaves and cumulative thermal stress on cold-water upwelling coral refugia
title_sort assessment of the impacts of rapid marine heatwaves and cumulative thermal stress on cold water upwelling coral refugia
topic Coral habitat
upwelling
ocean warming
Marine Heatwave
Degree Heating Week
url https://www.tandfonline.com/doi/10.1080/19475705.2024.2448240
work_keys_str_mv AT pochunhsu assessmentoftheimpactsofrapidmarineheatwavesandcumulativethermalstressoncoldwaterupwellingcoralrefugia
AT roseangelitabanaomacagga assessmentoftheimpactsofrapidmarineheatwavesandcumulativethermalstressoncoldwaterupwellingcoralrefugia
AT roshinpraj assessmentoftheimpactsofrapidmarineheatwavesandcumulativethermalstressoncoldwaterupwellingcoralrefugia