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Jani Tanzil - One of the best experts on this subject based on the ideXlab platform.
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regional decline in growth rates of massive porites corals in southeast asia
Global Change Biology, 2013Co-Authors: Jani Tanzil, Richard P Dunne, B E Brown, Jen N Lee, Jaap A Kaandorp, Peter A ToddAbstract:This study reports the first well-replicated analysis of continuous coral growth records from warmer water reefs (mean annual sea surface temperatures (SST) >28.5 °C) around the Thai-Malay Peninsula in Southeast Asia. Based on analyses of 70 colonies sampled from 15 reefs within six locations, region-wide declines in coral calcification rate (ca. 18.6%), Linear Extension rate (ca. 15.4%) and skeletal bulk density (ca. 3.9%) were observed over a 31-year period from 1980 to 2010. Decreases in calcification and Linear Extension rates were observed at five of the six locations and ranged from ca. 17.2―21.6% and ca. 11.4―19.6%, respectively, whereas decline in skeletal bulk density was a consequence of significant reductions at only two locations (ca. 6.9% and 10.7%). A significant link between region-wide growth rates and average annual SST was found, and Porites spp. demonstrated a high thermal threshold of ca. 29.4 °C before calcification rates declined. Responses at individual locations within the region were more variable with links between SST and calcification rates being significant at only four locations. Rates of sea temperature warming at locations in the Andaman Sea (Indian Ocean) (ca. 1.3 °C per decade) were almost twice those in the South China Sea (Pacific Ocean) (ca. 0.7 °C per decade), but this was not reflected in the magnitude of calcification declines at corresponding locations. Considering that massive Porites spp. are major reef builders around Southeast Asia, this region-wide growth decline is a cause for concern for future reef accretion rates and resilience. However, this study suggests that the future rates and patterns of change within the region are unlikely to be uniform or dependent solely on the rates of change in the thermal environment.
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decline in skeletal growth of the coral porites lutea from the andaman sea south thailand between 1984 and 2005
Coral Reefs, 2009Co-Authors: Jani Tanzil, Barbara E Brown, Alexander W Tudhope, Richard P DunneAbstract:Of the few studies that have examined in situ coral growth responses to recent climate change, none have done so in equatorial waters subject to relatively high sea temperatures (annual mean >27°C). This study compared the growth rate of Porites lutea from eight sites at Phuket, South Thailand between two time periods (December 1984–November 1986 and December 2003–November 2005). There was a significant decrease in coral calcification (23.5%) and Linear Extension rates (19.4–23.4%) between the two sampling periods at a number of sites, while skeletal bulk density remained unchanged. Over the last 46 years, sea temperatures (SST) in the area have risen at a rate of 0.161°C per decade (current seasonal temperature range 28–30°C) and regression analysis of coral growth data is consistent with a link between rising temperature and reduced Linear Extension in the order of 46–56% for every 1°C rise in SST. The apparent sensitivity of Linear Extension in P. lutea to increased SST suggests that corals in this part of the Andaman Sea may already be subjected to temperatures beyond their thermal optimum for skeletal growth.
Janice M Lough - One of the best experts on this subject based on the ideXlab platform.
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spatial temporal and taxonomic variation in coral growth implications for the structure and function of coral reef ecosystems
Oceanography and Marine Biology: an annual review, 2015Co-Authors: Morgan S Pratchett, Kristen Anderson, Mia O Hoogenboom, Elizabeth Widman, Andrew H Baird, John M Pandolfi, Peter J Edmunds, Janice M LoughAbstract:Growth is a fundamental biological trait, generally considered to have an important role in structuring populations and communities. Accordingly, many studies have quantified growth rates of scleractinian corals, but using a variety of different methods and measures that may or may not be comparable. The purpose of this review is to compile extensive data on the growth of corals, to relate disparate methods of measuring coral growth, and to explore spatial, temporal, and taxonomic variation in growth rates. The most common metric of coral growth is Linear Extension, measured as unidirectional change in branch length or colony radius. Rates of Linear Extension vary greatly among corals, being highest among arborescent Acropora species. This is not unexpected given the limited carbonate investment in producing long, slender branches compared to solid hemispherical colonies. However, differences in the way that Extension rates are actually measured (e.g., Linear Extension of individual branches vs. changes in the mean solid radius of massive corals) could potentially bias interspecific comparisons of coral growth. The most comparable measure of growth, which gives unbiased estimates of growth across different growth forms, is average annual calcification or change in weight normalized to a measure of size. Surprisingly, even calcification rates appear to be much higher for branching Acropora compared to other coral genera, which contributes to the high Extension rates recorded for this genus. Despite inconsistencies and incompatibilities among studies of coral growth, there is clear evidence that coral growth rates vary spatially and temporally, largely in response to light and water quality (e.g., turbidity), temperature, and aragonite saturation state. Ongoing changes in environmental conditions (e.g., due to climate change) are expected to have generally negative consequences for the growth of scleractinian corals, which may be further exacerbated by shifts in assemblage structure towards relatively slowgrowing species.
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declining coral calcification in massive porites in two nearshore regions of the northern great barrier reef
Global Change Biology, 2008Co-Authors: Glenn Death, Timothy F Cooper, Katharina E Fabricius, Janice M LoughAbstract:Temporal and spatial variation in the growth parameters skeletal density, Linear Extension and calcification rate in massive Porites from two nearshore regions of the northern Great Barrier Reef (GBR) were examined over a 16-year study period. Calcification rates in massive Porites have declined by approximately 21% in two regions on the GBR � 450km apart. This is a function primarily of a decrease in Linear Extension (� 16%) with a smaller decline in skeletal density (� 6%) and contrasts with previous studies on the environmental controls on growth of massive Porites on the GBR. Changes in the growth parameters were Linear over time. Averaged across colonies, skeletal density declined over time from 1.32gcm � 3 (SE 50.017) in 1988 to 1.25gcm � 3 (0.013) in 2003, equivalent to 0.36%yr � 1 (0.13). Annual Extension declined from 1.52cmyr � 1 (0.035) to 1.28cmyr � 1 (0.026), equivalent to 1.02%yr � 1 (0.39). Calcification rates (the product of skeletal density and annual Extension) declined from 1.96gcm � 2 yr � 1 (0.049) to 1.59gcm � 2 yr � 1 (0.041), equivalent to 1.29%yr � 1 (0.30). Mean annual seawater temperatures had no effect on skeletal density, but a modal effect on annual Extension and calcification with maxima at � 26.71C. There were minor differences in the growth parameters between regions. A decline in coral calcification of this magnitude with increasing seawater temperatures is unprecedented in recent centuries based on analysis of growth records from long cores of massive Porites. We discuss the decline in calcification within the context of known environmental controls on coral growth. Although our findings are consistent with studies of the synergistic effect of elevated seawater temperatures and pCO2 on coral calcification, we conclude that further data on seawater chemistry of the GBR are required to better understand the links between environmental change and effects on coral growth.
Ian C. Enochs - One of the best experts on this subject based on the ideXlab platform.
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Plasticity in skeletal characteristics of nursery-raised staghorn coral, Acropora cervicornis
Coral Reefs, 2017Co-Authors: Ilsa B. Kuffner, Erich Bartels, Anastasios Stathakopoulos, Ian C. Enochs, G. Kolodziej, Lauren T. Toth, Derek P. ManzelloAbstract:Staghorn coral, Acropora cervicornis , is a threatened species and the primary focus of western Atlantic reef restoration efforts to date. We compared Linear Extension, calcification rate, and skeletal density of nursery-raised A. cervicornis branches reared for 6 months either on blocks attached to substratum or hanging from PVC trees in the water column. We demonstrate that branches grown on the substratum had significantly higher skeletal density, measured using computerized tomography, and lower Linear Extension rates compared to water-column fragments. Calcification rates determined with buoyant weighing were not statistically different between the two grow-out methods, but did vary among coral genotypes. Whereas skeletal density and Extension rates were plastic traits that depended on grow-out method, calcification rate was conserved. Our results show that the two rearing methods generate the same amount of calcium carbonate skeleton but produce colonies with different skeletal characteristics and suggest that there is genetically based variability in coral calcification performance.
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effects of light and elevated pco2 on the growth and photochemical efficiency of acropora cervicornis
Coral Reefs, 2014Co-Authors: Derek P. Manzello, Diego Lirman, Ian C. Enochs, S Schopmeyer, Renee Carlton, R Van HooidonkAbstract:The effects of light and elevated pCO2 on the growth and photochemical efficiency of the critically endangered staghorn coral, Acropora cervicornis, were examined experimentally. Corals were subjected to high and low treatments of CO2 and light in a fully crossed design and monitored using 3D scanning and buoyant weight methodologies. Calcification rates, Linear Extension, as well as colony surface area and volume of A. cervicornis were highly dependent on light intensity. At pCO2 levels projected to occur by the end of the century from ocean acidification (OA), A. cervicornis exhibited depressed calcification, but no change in Linear Extension. Photochemical efficiency (F v /F m ) was higher at low light, but unaffected by CO2. Amelioration of OA-depressed calcification under high-light treatments was not observed, and we suggest that the high-light intensity necessary to reach saturation of photosynthesis and calcification in A. cervicornis may limit the effectiveness of this potentially protective mechanism in this species. High CO2 causes depressed skeletal density, but not Linear Extension, illustrating that the measurement of Extension by itself is inadequate to detect CO2 impacts. The skeletal integrity of A. cervicornis will be impaired by OA, which may further reduce the resilience of the already diminished populations of this endangered species.
Timothy F Cooper - One of the best experts on this subject based on the ideXlab platform.
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declining coral calcification in massive porites in two nearshore regions of the northern great barrier reef
Global Change Biology, 2008Co-Authors: Glenn Death, Timothy F Cooper, Katharina E Fabricius, Janice M LoughAbstract:Temporal and spatial variation in the growth parameters skeletal density, Linear Extension and calcification rate in massive Porites from two nearshore regions of the northern Great Barrier Reef (GBR) were examined over a 16-year study period. Calcification rates in massive Porites have declined by approximately 21% in two regions on the GBR � 450km apart. This is a function primarily of a decrease in Linear Extension (� 16%) with a smaller decline in skeletal density (� 6%) and contrasts with previous studies on the environmental controls on growth of massive Porites on the GBR. Changes in the growth parameters were Linear over time. Averaged across colonies, skeletal density declined over time from 1.32gcm � 3 (SE 50.017) in 1988 to 1.25gcm � 3 (0.013) in 2003, equivalent to 0.36%yr � 1 (0.13). Annual Extension declined from 1.52cmyr � 1 (0.035) to 1.28cmyr � 1 (0.026), equivalent to 1.02%yr � 1 (0.39). Calcification rates (the product of skeletal density and annual Extension) declined from 1.96gcm � 2 yr � 1 (0.049) to 1.59gcm � 2 yr � 1 (0.041), equivalent to 1.29%yr � 1 (0.30). Mean annual seawater temperatures had no effect on skeletal density, but a modal effect on annual Extension and calcification with maxima at � 26.71C. There were minor differences in the growth parameters between regions. A decline in coral calcification of this magnitude with increasing seawater temperatures is unprecedented in recent centuries based on analysis of growth records from long cores of massive Porites. We discuss the decline in calcification within the context of known environmental controls on coral growth. Although our findings are consistent with studies of the synergistic effect of elevated seawater temperatures and pCO2 on coral calcification, we conclude that further data on seawater chemistry of the GBR are required to better understand the links between environmental change and effects on coral growth.
Derek P. Manzello - One of the best experts on this subject based on the ideXlab platform.
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Plasticity in skeletal characteristics of nursery-raised staghorn coral, Acropora cervicornis
Coral Reefs, 2017Co-Authors: Ilsa B. Kuffner, Erich Bartels, Anastasios Stathakopoulos, Ian C. Enochs, G. Kolodziej, Lauren T. Toth, Derek P. ManzelloAbstract:Staghorn coral, Acropora cervicornis , is a threatened species and the primary focus of western Atlantic reef restoration efforts to date. We compared Linear Extension, calcification rate, and skeletal density of nursery-raised A. cervicornis branches reared for 6 months either on blocks attached to substratum or hanging from PVC trees in the water column. We demonstrate that branches grown on the substratum had significantly higher skeletal density, measured using computerized tomography, and lower Linear Extension rates compared to water-column fragments. Calcification rates determined with buoyant weighing were not statistically different between the two grow-out methods, but did vary among coral genotypes. Whereas skeletal density and Extension rates were plastic traits that depended on grow-out method, calcification rate was conserved. Our results show that the two rearing methods generate the same amount of calcium carbonate skeleton but produce colonies with different skeletal characteristics and suggest that there is genetically based variability in coral calcification performance.
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effects of light and elevated pco2 on the growth and photochemical efficiency of acropora cervicornis
Coral Reefs, 2014Co-Authors: Derek P. Manzello, Diego Lirman, Ian C. Enochs, S Schopmeyer, Renee Carlton, R Van HooidonkAbstract:The effects of light and elevated pCO2 on the growth and photochemical efficiency of the critically endangered staghorn coral, Acropora cervicornis, were examined experimentally. Corals were subjected to high and low treatments of CO2 and light in a fully crossed design and monitored using 3D scanning and buoyant weight methodologies. Calcification rates, Linear Extension, as well as colony surface area and volume of A. cervicornis were highly dependent on light intensity. At pCO2 levels projected to occur by the end of the century from ocean acidification (OA), A. cervicornis exhibited depressed calcification, but no change in Linear Extension. Photochemical efficiency (F v /F m ) was higher at low light, but unaffected by CO2. Amelioration of OA-depressed calcification under high-light treatments was not observed, and we suggest that the high-light intensity necessary to reach saturation of photosynthesis and calcification in A. cervicornis may limit the effectiveness of this potentially protective mechanism in this species. High CO2 causes depressed skeletal density, but not Linear Extension, illustrating that the measurement of Extension by itself is inadequate to detect CO2 impacts. The skeletal integrity of A. cervicornis will be impaired by OA, which may further reduce the resilience of the already diminished populations of this endangered species.
