ORCID Profile
0000-0002-3412-703X
Current Organisations
Nanyang Technological University
,
University of Exeter
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Publisher: Elsevier BV
Date: 10-2014
Publisher: Elsevier BV
Date: 10-2012
DOI: 10.1016/J.MARENVRES.2012.08.001
Abstract: Skeletal extension, density and calcification rate of 12 scleractinian coral species comprising 7 morphological groups were examined on the reef crest of Vabbinfaru platform, Mal es. Growth rates of coral specimens were measured over the period of February 2010-March 2011 using alizarin staining and direct measurements. Skeletal extension rate was highly variable between coral species. Colony morphology was a major control on the skeletal extension and calcification of coral specimens. Growth rates of Acropora and Porites corals were comparable to existing data recorded for Caribbean and Indo-Pacific reef provinces. Skeletal density was less variable between species and was typically consistent among morphological groups. Findings represent the first estimates of coral growth in the central Indian Ocean region and add to the limited growth studies available that have examined a broad range of coral growth morphologies in other reef-building regions.
Publisher: Wiley
Date: 10-2016
DOI: 10.1002/ESP.3946
Publisher: Springer Science and Business Media LLC
Date: 20-05-2020
DOI: 10.1007/S00338-020-01953-3
Abstract: Globally, many coral reefs have fallen into negative carbonate budget states, where biological erosion exceeds carbonate production. The compounding effects of urbanization and climate change have caused reductions in coral cover and shifts in community composition that may limit the ability of reefs to maintain rates of vertical accretion in line with rising sea levels. Here we report on coral reef carbonate budget surveys across seven coral reefs in Singapore, which persist under chronic turbidity and in highly disturbed environmental conditions, with less than 20% light penetration to 2 m depth. Results show that mean net carbonate budgets across Singapore’s reefs were relatively low, at 0.63 ± 0.27 kg CaCO 3 m −2 yr −1 (mean ± 1 SE) with a range from − 1.56 to 1.97, compared with the mean carbonate budgets across the Indo-Pacific of 1.4 ± 0.15 kg CaCO 3 m −2 yr −1 , and isolated Indian Ocean reefs pre-2016 bleaching (~ 3.7 kg CaCO 3 m −2 yr −1 ). Of the seven reefs surveyed, only one reef had a net negative, or erosional budget, due to near total loss of coral cover ( 5% remaining coral). Mean gross carbonate production on Singapore’s reefs was dominated by stress-tolerant and generalist species, with low-profile morphologies, and was ~ 3 kg m −2 yr −1 lower than on reefs with equivalent coral cover elsewhere in the Indo-Pacific. While overall these reefs are maintaining and adding carbonate structure, their mean vertical accretion potential is below both current rates of sea level rise (1993–2010), and future predictions under RCP 4.5 and RCP 8.5 scenarios. This is likely to result in an increase of 0.2–0.6 m of water above Singapore’s reefs in the next 80 yr, further narrowing the depth range over which these reefs can persist.
Publisher: Informa UK Limited
Date: 03-2011
Publisher: Springer Science and Business Media LLC
Date: 16-12-2019
Publisher: Elsevier BV
Date: 08-2017
Publisher: Springer Science and Business Media LLC
Date: 06-2018
DOI: 10.1038/S41586-018-0194-Z
Abstract: Sea-level rise (SLR) is predicted to elevate water depths above coral reefs and to increase coastal wave exposure as ecological degradation limits vertical reef growth, but projections lack data on interactions between local rates of reef growth and sea level rise. Here we calculate the vertical growth potential of more than 200 tropical western Atlantic and Indian Ocean reefs, and compare these against recent and projected rates of SLR under different Representative Concentration Pathway (RCP) scenarios. Although many reefs retain accretion rates close to recent SLR trends, few will have the capacity to track SLR projections under RCP4.5 scenarios without sustained ecological recovery, and under RCP8.5 scenarios most reefs are predicted to experience mean water depth increases of more than 0.5 m by 2100. Coral cover strongly predicts reef capacity to track SLR, but threshold cover levels that will be necessary to prevent submergence are well above those observed on most reefs. Urgent action is thus needed to mitigate climate, sea-level and future ecological changes in order to limit the magnitude of future reef submergence.
Publisher: Springer Science and Business Media LLC
Date: 22-04-2021
Publisher: MDPI AG
Date: 02-10-2020
DOI: 10.3390/D12100379
Abstract: Parrotfish provide important ecological functions on coral reefs, including the provision of new settlement space through grazing and the generation of sediment through bioerosion of reef substrate. Estimating these functions at an ecosystem level depends on accurately quantifying the functional impact of in iduals, yet parrotfish feeding metrics are only available for a limited range of sites, species and size classes. We quantified bite rates, proportion of bites leaving scars and scar sizes in situ for the dominant excavator (Cetoscarus ocellatus, Chlorurus strongylocephalus, Ch. sordidus) and scraper species (Scarus rubroviolaceus, S. frenatus, S. niger, S. tricolor, S. scaber, S. psittacus) in the central Indian Ocean. This includes the first record of scar frequencies and sizes for the latter three species. Bite rates varied with species and life phase and decreased with body size. The proportion of bites leaving scars and scar sizes differed among species and increased with body size. Species-level allometric relationships between body size and each of these feeding metrics were used to parameterize annual in idual grazing and bioerosion rates which increase non-linearly with body size. Large in iduals of C. ocellatus, Ch. strongylocephalus and S. rubroviolaceus can graze 200–400 m2 and erode kg of reef substrate annually. Smaller species graze 1–100 m2 yr−1 and erode 0.2–30 kg yr−1. We used these in idual functional rates to quantify community grazing and bioerosion levels at 15 sites across the Mal es and the Chagos Archipelago. Although parrotfish density was 2.6 times higher on Mal ian reefs, average grazing (3.9 ± 1.4 m2 m−2 reef yr−1) and bioerosion levels (3.1 ± 1.2 kg m−2 reef yr−1) were about 15% lower than in the Chagos Archipelago (4.5 ± 2.3 and 3.7 ± 3.0, respectively), due to the dominance of small species and in iduals in the Mal es (90% cm length). This demonstrates that large-bodied species and in iduals contribute disproportionally to both grazing and bioerosion. Across all sites, grazing increased by 66 ± 5 m2 ha−1 and bioerosion by 109 ± 9 kg ha−1 for every kg increase in parrotfish biomass. However, for a given level of parrotfish biomass, grazing and bioerosion levels were higher on Mal ian reefs than in the Chagos Archipelago. This suggests that small-bodied fish assemblages can maintain ecosystem functions, but only if key species are present in sufficiently high numbers.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/MF13155
Abstract: Coral reefs are formed by the growth and calcification of primary coral framework and secondary encrusting organisms. Future scenarios of reef health predict global declines in coral cover and an increase in the relative importance of encrusting organisms to gross reef calcification. Numerous coral growth studies are available however, there are few quantitative estimates of secondary carbonate production on reefs. The present study used vertically orientated PVC pipe to generate rates of carbonate production (g cm–2 year–1) by encruster communities on Vabbinfaru reef platform, Mal es (4°18′35″N, 73°25′26″E). Maximum carbonate production by encrusters was 0.112 g cm–2 year–1 (mean ± s.d.: 0.047 ± 0.019 g cm–2 year–1). Encruster community composition was dominated by non-geniculate coralline algae (mean ± s.d.: 76 ± 14.2%), with other encrusting taxa being quantitatively unimportant to total substrate cover (mean ± s.d.: 9 ± 16.7%). Rates of encruster calcification at Vabbinfaru fell within the range of values reported for other reef-building provinces. There is a particular need for more quantitative field-based measurements of reef-organism calcification rates because such values strengthen regional and global estimates of gross carbonate production and have direct implications for net reef accretion and the development of reef sedimentary environments.
Publisher: Elsevier BV
Date: 07-2016
Publisher: Geological Society of America
Date: 06-2015
DOI: 10.1130/G36623.1
Publisher: Springer Science and Business Media LLC
Date: 11-01-2022
DOI: 10.1038/S43247-021-00338-W
Abstract: Sea-level rise is expected to outpace the capacity of coral reefs to grow and maintain their wave protection function, exacerbating coastal flooding and erosion of adjacent shorelines and threatening coastal communities. Here we present a new method that yields highly-resolved direct measurements of contemporary reef accretion on a Mal ian atoll reef rim, the critical zone that induces wave breaking. Results incorporate the suite of physical and ecological processes that contribute to reef accumulation and show growth rates vary from 6.6 ± 12.5 mm.y −1 on the reef crest, and up to 3.1 ± 10.2 mm.y −1 , and −0.5 ± 1.8 mm.yr −1 on the outer and central reef flat respectively. If these short-term results are maintained over decades, the reef crest could keep pace with current sea-level rise. Findings highlight the need to resolve contemporary reef accretion at the critical wave dissipation zone to improve predictions of future reef growth, and re-evaluate exposure of adjacent shorelines to coastal hazards.
Publisher: MDPI AG
Date: 07-06-2021
DOI: 10.3390/D13060251
Abstract: Increasing evidence suggests that coral reefs exposed to elevated turbidity may be more resilient to climate change impacts and serve as an important conservation hotspot. However, logistical difficulties in studying turbid environments have led to poor representation of these reef types within the scientific literature, with studies using different methods and definitions to characterize turbid reefs. Here we review the geological origins and growth histories of turbid reefs from the Holocene (past), their current ecological and environmental states (present), and their potential responses and resilience to increasing local and global pressures (future). We classify turbid reefs using new descriptors based on their turbidity regime (persistent, fluctuating, transitional) and sources of sediment input (natural versus anthropogenic). Further, by comparing the composition, function and resilience of two of the most studied turbid reefs, Paluma Shoals Reef Complex, Australia (natural turbidity) and Singapore reefs (anthropogenic turbidity), we found them to be two distinct types of turbid reefs with different conservation status. As the geographic range of turbid reefs is expected to increase due to local and global stressors, improving our understanding of their responses to environmental change will be central to global coral reef conservation efforts.
Publisher: Springer Science and Business Media LLC
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 19-07-2016
DOI: 10.1038/SREP29616
Abstract: Mean coral cover has reportedly declined by over 15% during the last 30 years across the central Great Barrier Reef (GBR). Here, we present new data that documents widespread reef development within the more poorly studied turbid nearshore areas ( m depth), and show that coral cover on these reefs averages 38% (twice that reported on mid- and outer-shelf reefs). Of the surveyed seafloor area, 11% had distinct reef or coral community cover. Although the survey area represents a small subset of the nearshore zone (15.5 km 2 ), this reef density is comparable to that measured across the wider GBR shelf (9%). We also show that cross-shelf coral cover declines with distance from the coast (R 2 = 0.596). Identified coral taxa (21 genera) exhibited clear depth-stratification, corresponding closely to light attenuation and seafloor topography, with reefal development restricted to submarine antecedent bedforms. Data from this first assessment of nearshore reef occurrence and ecology measured across meaningful spatial scales suggests that these coral communities may exhibit an unexpected capacity to tolerate documented declines in water quality. Indeed, these shallow-water nearshore reefs may share many characteristics with their deep-water ( m) mesophotic equivalents and may have similar potential as refugia from large-scale disturbances.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Kyle Morgan.