A new model of Holocene reef initiation and growth in response to sea-level rise on the Southern Great Barrier Reef

Sanborn, Kelsey; Webster, Jody M.; Webb, Gregory E.; Braga, Juan C.; Humblet, Marc; Nothdurft, Luke D.; Patterson, Madhavi A.; Dechnik, Belinda; Warner, Susan; Graham, Trevor; Murphy, Richard J.; Yokoyama, Yūsuke; Obrochta, Stephen; Zhao, Jie; Salas-Saavedra, Marcos

doi:10.1016/j.sedgeo.2019.105556

Cited by 21 publications

(9 citation statements)

References 86 publications

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“…Most types of habitats have the same trends as the general pattern of reef development, except the backreef zone that has a sharp increase around 6 ka. This mid-Holocene increase in backreef habitats has previously been observed in several parts of the Indo-Pacific region (Camoin and Webster 2015), including on the Great Barrier Reef (Sanborn et al 2020). Around this time, the sea level reached its present position ( Fig.…”

Section: Contraction-expansion Dynamics Of Coral Reefs In Response Tosupporting

confidence: 70%

Contraction-expansion dynamics of reef species in response to sea-level changes

Hoareau

2021

Preprint

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The contraction-expansion model (CEM) describes the dynamics of species that survived in refugia during the last glacial maximum (LGM) and expanded their range when environmental conditions slowly improved from the Late Glacial through to the Holocene. The CEM has been proposed to describe the dynamics of reef species in response to sea-level fluctuations from a range of disciplines, but genetic inferences rather suggest stable population sizes since the last glacial period. Here, we address this paradox by providing a new model of modern reef development, by assessing the effect of LGM bottlenecks using genetic simulations, and by using a survey of the literature on reef species to compile both estimates of times to expansion and applied rates of molecular evolution. Using previously published radiocarbon dates of core data, we propose a synthetic model for the dynamics of modern coral reefs in the Indo-Pacific region. This model describes both an initiation at 9.9 ka and subsequent development that confirms a strong influence of sea-level fluctuations on reef dynamics. Simulations based on mtDNA datasets showed that pre-LGM genetic signatures of expansion are lost. Recent literature shows that, although genetic expansions of tropical marine species are frequent (>95%), the onset of these expansions is old (median ~110 ka), which indicates that most populations have remained stable since before the LGM. These pre-LGM expansions are explained by the low mutation rates (1.66% changes/site/Myr) known to be inadequate to calibrate time at population level. Specific calibrations should help solve the paradox and generalise the CEM for reef species.

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Section: Contraction-expansion Dynamics Of Coral Reefs In Response Tosupporting

confidence: 70%

Contraction-expansion dynamics of reef species in response to sea-level changes

Hoareau

2021

Preprint

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“…grew in relatively shallow, clear waters, which are representative of conditions which are still found in parts of the contemporary GBR. During this time, coral reef vertical accretion occurred at a rate of 0.2-1.1 cm yr -1 (mean 0.5 cm yr -1 ) (Sanborn et al, 2020). Therefore, if sea level rise in the GBR remains below ~1 cm yr -1 , coral vertical accretion could keep pace with the rate of sea level rise.…”

Section: Discussionmentioning

confidence: 96%

“…Sea level rise and the rate of coral reef vertical accretion is also likely to affect coral physiological stress and DMS emissions. Global mean sea level is predicted to rise by 40-80 cm under an end of century climate (Sanborn et al, 2020). In the late Holocene in the GBR, fast-growing branching corals (such as Acropora spp.)…”

Section: Discussionmentioning

confidence: 99%

CMIP6 projections of ocean warming and the impact on dimethylsulfide emissions from the Great Barrier Reef, Australia

Jackson

Woodhouse²,

Gabric³

et al. 2022

Front. Mar. Sci.

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Coral reefs are important regional sources of biogenic sulfur to the tropical marine atmosphere, through stress-induced emissions of dimethylsulfide (DMS). Recent estimates suggest that the Great Barrier Reef (GBR), Australia emits 0.02-0.05 Tg yr-1 of DMS (equivalent to 0.010-0.026 Tg yr-1 S), with potential implications for local aerosol-cloud processes. However, the impact of ocean warming on DMS emissions from coral reefs remains uncertain, complicating efforts to improve the representation of coral reefs in DMS climatologies and climate models. We investigate the influence of predicted changes in sea surface temperature (SST), photosynthetically active radiation (PAR) and wind speed on contemporary DMS emissions from the GBR using model output from the Coupled Model Intercomparison Project Phase 6 (CMIP6). A multiple linear regression is used to calculate seawater surface DMS (DMSw) concentration in the GBR in a contemporary (2001-2020) and end-of-century (2081-2100) scenario, as simulated by CMIP6 models under a SSP2-4.5 and SSP5-8.5 Shared Socioeconomic Pathway. By the end of this century, a 1.5-3.0°C rise in annual mean SST and a 1.1-1.7 mol m-2 d-1 increase in PAR could increase DMSw concentration in the GBR by 9.2-14.5%, leading to an increase in DMS flux of 9.5-14.3%. Previous model studies have suggested that the aerosol system has a low sensitivity to relatively large changes in coral reef-derived DMS. Therefore, the predicted change in contemporary DMS emissions is unlikely to influence the regional atmosphere. Further research is needed to understand the combined effects of temperature, light, pH, salinity and ecosystem structure on DMS production in coral reefs to better predict potential changes in emissions. Nevertheless, the findings provide insight into how predicted ocean warming may affect present-day DMS emissions and the source-strength of the GBR to the atmospheric sulfur budget.

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“…It is a part of the Capricorn-Bunker group about 90 km east of Port Gladstone in Queensland, Australia. The University of Sydney maintains the research station on the island, and as such, the One Tree Island reef has been the subject of detailed biological and geological investigation over the past four decades (see [46][47][48]), including studies using remote sensing [49]. Hence, the reef habitats and geomorphic zones characterising the One Tree Island reef have been well studied.…”

Section: Study Areamentioning

confidence: 99%

Reef-Insight: A Framework for Reef Habitat Mapping with Clustering Methods Using Remote Sensing

2023

Self Cite

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Environmental damage has been of much concern, particularly in coastal areas and the oceans, given climate change and the drastic effects of pollution and extreme climate events. Our present-day analytical capabilities, along with advancements in information acquisition techniques such as remote sensing, can be utilised for the management and study of coral reef ecosystems. In this paper, we present Reef-Insight, an unsupervised machine learning framework that features advanced clustering methods and remote sensing for reef habitat mapping. Our framework compares different clustering methods for reef habitat mapping using remote sensing data. We evaluate four major clustering approaches based on qualitative and visual assessments which include k-means, hierarchical clustering, Gaussian mixture model, and density-based clustering. We utilise remote sensing data featuring the One Tree Island reef in Australia’s Southern Great Barrier Reef. Our results indicate that clustering methods using remote sensing data can well identify benthic and geomorphic clusters in reefs when compared with other studies. Our results indicate that Reef-Insight can generate detailed reef habitat maps outlining distinct reef habitats and has the potential to enable further insights for reef restoration projects.

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A new model of Holocene reef initiation and growth in response to sea-level rise on the Southern Great Barrier Reef

Cited by 21 publications

References 86 publications

Contraction-expansion dynamics of reef species in response to sea-level changes

Contraction-expansion dynamics of reef species in response to sea-level changes

CMIP6 projections of ocean warming and the impact on dimethylsulfide emissions from the Great Barrier Reef, Australia

Reef-Insight: A Framework for Reef Habitat Mapping with Clustering Methods Using Remote Sensing

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