scholarly journals Changing dynamics of Caribbean reef carbonate budgets: emergence of reef bioeroders as critical controls on present and future reef growth potential

2014 ◽  
Vol 281 (1796) ◽  
pp. 20142018 ◽  
Author(s):  
Chris T. Perry ◽  
Gary N. Murphy ◽  
Paul S. Kench ◽  
Evan N. Edinger ◽  
Scott G. Smithers ◽  
...  
Keyword(s):  
Coral Cover ◽  
Coral Community ◽  
Growth Potential ◽  
Reef Growth ◽  
Carbonate Production ◽  
Erosion Rates ◽  
Caribbean Reef ◽  
Carbonate Budget ◽  
Coral Recovery ◽  
Fundamental Shift

Coral cover has declined rapidly on Caribbean reefs since the early 1980s, reducing carbonate production and reef growth. Using a cross-regional dataset, we show that widespread reductions in bioerosion rates—a key carbonate cycling process—have accompanied carbonate production declines. Bioerosion by parrotfish, urchins, endolithic sponges and microendoliths collectively averages 2 G (where G = kg CaCO 3 m −2 yr −1 ) (range 0.96–3.67 G). This rate is at least 75% lower than that reported from Caribbean reefs prior to their shift towards their present degraded state. Despite chronic overfishing, parrotfish are the dominant bioeroders, but erosion rates are reduced from averages of approximately 4 to 1.6 G. Urchin erosion rates have declined further and are functionally irrelevant to bioerosion on most reefs. These changes demonstrate a fundamental shift in Caribbean reef carbonate budget dynamics. To-date, reduced bioerosion rates have partially offset carbonate production declines, limiting the extent to which more widespread transitions to negative budget states have occurred. However, given the poor prognosis for coral recovery in the Caribbean and reported shifts to coral community states dominated by slower calcifying taxa, a continued transition from production to bioerosion-controlled budget states, which will increasingly threaten reef growth, is predicted.

scholarly journals Drivers and predictions of coral reef carbonate budget trajectories

2017 ◽  
Vol 284 (1847) ◽  
pp. 20162533 ◽  
Author(s):  
Fraser A. Januchowski-Hartley ◽  
Nicholas A. J. Graham ◽  
Shaun K. Wilson ◽  
Simon Jennings ◽  
Chris T. Perry
Keyword(s):  
Coral Reef ◽  
Regime Shift ◽  
Coral Cover ◽  
Growth Potential ◽  
Bleaching Event ◽  
Reef Growth ◽  
Carbonate Production ◽  
Carbonate Budget ◽  
Term Maintenance

Climate change is one of the greatest threats to the long-term maintenance of coral-dominated tropical ecosystems, and has received considerable attention over the past two decades. Coral bleaching and associated mortality events, which are predicted to become more frequent and intense, can alter the balance of different elements that are responsible for coral reef growth and maintenance. The geomorphic impacts of coral mass mortality have received relatively little attention, particularly questions concerning temporal recovery of reef carbonate production and the factors that promote resilience of reef growth potential. Here, we track the biological carbonate budgets of inner Seychelles reefs from 1994 to 2014, spanning the 1998 global bleaching event when these reefs lost more than 90% of coral cover. All 21 reefs had positive budgets in 1994, but in 2005 budgets were predominantly negative. By 2014, carbonate budgets on seven reefs were comparable with 1994, but on all reefs where an ecological regime shift to macroalgal dominance occurred, budgets remained negative through 2014. Reefs with higher massive coral cover, lower macroalgae cover and lower excavating parrotfish biomass in 1994 were more likely to have positive budgets post-bleaching. If mortality of corals from the 2016 bleaching event is as severe as that of 1998, our predictions based on past trends would suggest that six of eight reefs with positive budgets in 2014 would still have positive budgets by 2030. Our results highlight that reef accretion and framework maintenance cannot be assumed from the ecological state alone, and that managers should focus on conserving aspects of coral reefs that support resilient carbonate budgets.

scholarly journals Functional consequences of the long-term decline of reef-building corals in the Caribbean: evidence of across-reef functional convergence

2019 ◽  
Vol 6 (10) ◽  
pp. 190298 ◽  
Author(s):  
Nuria Estrada-Saldívar ◽  
Eric Jordán-Dalhgren ◽  
Rosa E. Rodríguez-Martínez ◽  
Chris Perry ◽  
Lorenzo Alvarez-Filip
Keyword(s):  
Community Composition ◽  
Coral Species ◽  
Coral Cover ◽  
Coral Community ◽  
Back Reef ◽  
Anthropogenic Pressures ◽  
Carbonate Production ◽  
Fore Reef ◽  
Functional Integrity ◽  
Reef Zones

Functional integrity on coral reefs is strongly dependent upon coral cover and coral carbonate production rate being sufficient to maintain three-dimensional reef structures. Increasing environmental and anthropogenic pressures in recent decades have reduced the cover of key reef-building species, producing a shift towards the relative dominance of more stress-tolerant taxa and leading to a reduction in the physical functional integrity. Understanding how changes in coral community composition influence the potential of reefs to maintain their physical reef functioning is a priority for their conservation and management. Here, we evaluate how coral communities have changed in the northern sector of the Mexican Caribbean between 1985 and 2016, and the implications for the maintenance of physical reef functions in the back- and fore-reef zones. We used the cover of coral species to explore changes in four morpho-functional groups, coral community composition, coral community calcification, the reef functional index and the reef carbonate budget. Over a period of 31 years, ecological homogenization occurred between the two reef zones mostly due to a reduction in the cover of framework-building branching ( Acropora spp.) and foliose-digitiform ( Porites porites and Agaricia tenuifolia ) coral species in the back-reef, and a relative increase in non-framework species in the fore-reef ( Agaricia agaricites and Porites astreoides ). This resulted in a significant decrease in the physical functionality of the back-reef zone. At present, both reef zones have negative carbonate budgets, and thus limited capacity to sustain reef accretion, compromising the existing reef structure and its future capacity to provide habitat and environmental services.

scholarly journals The mortality, recovery, and community shifts of scleractinian corals in Puerto Rico one decade after the 2005 regional bleaching event

2017 ◽  
Author(s):  
Jorge R García-Sais ◽  
Stacey M Williams ◽  
Ali Amirrezvani
Keyword(s):  
Puerto Rico ◽  
Coral Cover ◽  
Light Attenuation ◽  
Coral Community ◽  
Scleractinian Corals ◽  
Partial Recovery ◽  
Bleaching Event ◽  
Before And After ◽  
Coral Recovery ◽  
And Shifts

This work analyzes the mortality, recovery, and shifts in the composition of scleractinian corals in Puerto Rico one decade after the 2005 regional coral bleaching event. Temporal and spatial patterns of coral community structure were examined using a stratified, non-random sampling approach based on five permanent transects per reef at 16 reef stations. A negative correlation between percent coral cover loss and light attenuation coefficient (Kd490) was observed, suggesting that water turbidity played a major role in coral protection during the bleaching event (“sunblock effect”). Loss of coral cover after the bleaching event was lower at nearshore reefs, and with increasing depth at oceanic and shelf-edge reefs. By 2015, coral recovery was observed at all reefs surveyed, but coastal reefs exhibited a higher rate of recovery. The responses of coral assemblages varied after the bleaching event, including shifts in cover from massive corals (Orbicella spp.) to turf algae and/or by opportunistic (Porites astreoides) and branching corals (Madracis auretenra, P. porites); partial recovery by O. annularis complex; and no measurable change in coral assemblages before and after the event.

scholarly journals The mortality, recovery, and community shifts of scleractinian corals in Puerto Rico one decade after the 2005 regional bleaching event

2017 ◽  
Author(s):  
Jorge R García-Sais ◽  
Stacey M Williams ◽  
Ali Amirrezvani
Keyword(s):  
Puerto Rico ◽  
Coral Cover ◽  
Light Attenuation ◽  
Coral Community ◽  
Scleractinian Corals ◽  
Partial Recovery ◽  
Bleaching Event ◽  
Before And After ◽  
Coral Recovery ◽  
And Shifts

This work analyzes the mortality, recovery, and shifts in the composition of scleractinian corals in Puerto Rico one decade after the 2005 regional coral bleaching event. Temporal and spatial patterns of coral community structure were examined using a stratified, non-random sampling approach based on five permanent transects per reef at 16 reef stations. A negative correlation between percent coral cover loss and light attenuation coefficient (Kd490) was observed, suggesting that water turbidity played a major role in coral protection during the bleaching event (“sunblock effect”). Loss of coral cover after the bleaching event was lower at nearshore reefs, and with increasing depth at oceanic and shelf-edge reefs. By 2015, coral recovery was observed at all reefs surveyed, but coastal reefs exhibited a higher rate of recovery. The responses of coral assemblages varied after the bleaching event, including shifts in cover from massive corals (Orbicella spp.) to turf algae and/or by opportunistic (Porites astreoides) and branching corals (Madracis auretenra, P. porites); partial recovery by O. annularis complex; and no measurable change in coral assemblages before and after the event.

scholarly journals Assessing population collapse of Drupella spp. (Mollusca: Gastropoda) 2 years after a coral bleaching event in the Republic of Maldives

Hydrobiologia ◽  
2021 ◽  
Author(s):  
L. Saponari ◽  
I. Dehnert ◽  
P. Galli ◽  
S. Montano
Keyword(s):  
Coral Bleaching ◽  
Prey Availability ◽  
Coral Cover ◽  
Environmental Data ◽  
High Plasticity ◽  
Bleaching Event ◽  
Coral Recovery ◽  
The Republic ◽  
The Impact ◽  
Line Intercept

AbstractCorallivory causes considerable damage to coral reefs and can exacerbate other disturbances. Among coral predators, Drupella spp. are considered as delayer of coral recovery in the Republic of Maldives, although little information is available on their ecology. Thus, we aimed to assess their population structure, feeding behaviour and spatial distribution around 2 years after a coral bleaching event in 2016. Biological and environmental data were collected using belt and line intercept transects in six shallow reefs in Maldives. The snails occurred in aggregations with a maximum of 62 individuals and exhibited a preference for branching corals. Yet, the gastropods showed a high plasticity in adapting feeding preferences to prey availability. Drupella spp. were homogenously distributed in the study area with an average of 9.04 ± 19.72 ind/200 m2. However, their occurrence was significantly different at the reef scale with the highest densities found in locations with higher coral cover. The impact of Drupella spp. appeared to be minimal with the population suffering from the loss of coral cover. We suggest that monitoring programs collect temporal- and spatial-scale data on non-outbreaking populations or non-aggregating populations to understand the dynamics of predation related to the co-occurrence of anthropogenic and natural impacts.

Coral community composition and carbonate production in an urbanized seascape

2021 ◽  
pp. 105322
Author(s):  
Chin Soon Lionel Ng ◽  
Yong Kit Samuel Chan ◽  
Nhung Thi Hong Nguyen ◽  
Yuichi Preslie Kikuzawa ◽  
Shu Qin Sam ◽  
...  
Keyword(s):  
Community Composition ◽  
Coral Community ◽  
Carbonate Production

scholarly journals Evaluation of coral reef carbonate production models at a global scale

2015 ◽  
Vol 12 (5) ◽  
pp. 1339-1356 ◽  
Author(s):  
N. S. Jones ◽  
A. Ridgwell ◽  
E. J. Hendy
Keyword(s):  
Coral Reef ◽  
Predictive Power ◽  
Numerical Models ◽  
Coral Cover ◽  
Light Availability ◽  
Global Scale ◽  
Data Set ◽  
Carbonate Production ◽  
Future Global Warming ◽  
Atmospheric Co2 Concentrations

Abstract. Calcification by coral reef communities is estimated to account for half of all carbonate produced in shallow water environments and more than 25% of the total carbonate buried in marine sediments globally. Production of calcium carbonate by coral reefs is therefore an important component of the global carbon cycle; it is also threatened by future global warming and other global change pressures. Numerical models of reefal carbonate production are needed for understanding how carbonate deposition responds to environmental conditions including atmospheric CO2 concentrations in the past and into the future. However, before any projections can be made, the basic test is to establish model skill in recreating present-day calcification rates. Here we evaluate four published model descriptions of reef carbonate production in terms of their predictive power, at both local and global scales. We also compile available global data on reef calcification to produce an independent observation-based data set for the model evaluation of carbonate budget outputs. The four calcification models are based on functions sensitive to combinations of light availability, aragonite saturation (Ωa) and temperature and were implemented within a specifically developed global framework, the Global Reef Accretion Model (GRAM). No model was able to reproduce independent rate estimates of whole-reef calcification, and the output from the temperature-only based approach was the only model to significantly correlate with coral-calcification rate observations. The absence of any predictive power for whole reef systems, even when consistent at the scale of individual corals, points to the overriding importance of coral cover estimates in the calculations. Our work highlights the need for an ecosystem modelling approach, accounting for population dynamics in terms of mortality and recruitment and hence calcifier abundance, in estimating global reef carbonate budgets. In addition, validation of reef carbonate budgets is severely hampered by limited and inconsistent methodology in reef-scale observations.

scholarly journals Temperate carbonate cycling and water mass properties from intertidal to bathyal depths (Azores, N-Atlantic)

2010 ◽  
Vol 7 (3) ◽  
pp. 3297-3333 ◽  
Author(s):  
M. Wisshak ◽  
A. Form ◽  
J. Jakobsen ◽  
A. Freiwald
Keyword(s):  
Cold Water ◽  
Light Availability ◽  
Euphotic Zone ◽  
Carbonate Production ◽  
Carbonate Budget ◽  
Mass Properties ◽  
Accretion Rates ◽  
Key Factor ◽  
Temperate Carbonate ◽  
Factor Governing

Abstract. The rugged submarine topography of the Azores supports a diverse heterozoan association resulting in intense biotically-controlled carbonate production and accumulation. In order to characterise this cold-water (C) factory a 2-year experiment was carried out to study the biodiversity of hardground communities and for budgeting carbonate production and degradation along a bathymetrical transect from the intertidal to bathyal 500 m depth. Seasonal temperatures peak in September (above a thermocline) and bottom in March (stratification diminishes) with a decrease in amplitude and absolute values with depth, and with tidal-driven short-term fluctuations. Measured seawater stable isotope ratios and levels of dissolved nutrients decrease with depth, as do the calcium carbonate saturation states. The photosynthetic active radiation shows a base of the euphotic zone in ~70 m and a dysphotic limit in ~150 m depth. Bioerosion, being primarily a function of light availability for phototrophic endoliths and grazers feeding upon them, is ~10 times stronger on the illuminated upside versus the shaded underside of substrates in the photic zone, with maximum rates in the intertidal (−631 g/m2/yr). Rates rapidly decline towards deeper waters where bioerosion and carbonate accretion are slow and epibenthic/endolithic communities take years to mature. Accretion rates are highest in the lower euphotic zone (955 g/m2/yr), where the substrate is less prone to hydrodynamic force. Highest rates are found – inversely to bioerosion – on downward facing substrates, suggesting that bioerosion may be a key factor governing the preferential settlement and growth of calcareous epilithobionts on downward facing substrates. In context of a latitudinal gradient, the Azores carbonate cycling rates plot between known values from the cold-temperate Swedish Kosterfjord and the tropical Bahamas, with a total range of two orders in magnitude. Carbonate budget calculations for the bathymetrical transect yield a mean 266.9 kg of epilithic carbonate production, −54.6 kg of bioerosion, and 212.3 kg of annual net carbonate production per metre of coastline in the Azores C factory.

scholarly journals Predicting coral adaptation to global warming in the Indo-West-Pacific

2019 ◽  
Author(s):  
Mikhail V. Matz ◽  
Eric Treml ◽  
Benjamin C. Haller
Keyword(s):  
New Caledonia ◽  
Coral Cover ◽  
First Century ◽  
Genetic Rescue ◽  
West Pacific ◽  
Connectivity Model ◽  
Wide Scale ◽  
Southern Half ◽  
Coral Recovery ◽  
Warming Rate

ABSTRACTThe potential of reef-building corals to adapt to increasing sea surface temperatures is often speculated about but has rarely been comprehensively modeled on a region-wide scale. Here, we used individual-based simulations to model adaptation to warming in a coral metapopulation comprising 680 reefs and representing the whole of the Central Indo-West Pacific. We find that in the first century of warming (approximately from 50 years ago to 50 years in the future) corals adapt rapidly by redistributing pre-existing adaptive alleles among populations (“genetic rescue”). In this way, some coral populations - most notably, Vietnam, Japan, Taiwan, New Caledonia, and the southern half of the Great Barrier Reef - appear to be able to maintain their fitness even under the worst warming scenarios (at least in theory, assuming the rate of evolution is the only limitation to local coral recovery). Still, survival of the majority of reefs in the region critically depends on the warming rate, underscoring the urgent need to curb carbon emissions. Conveniently, corals’ adaptive potential was largely independent of poorly known genetic parameters and could be predicted based on a simple metric derived from the biophysical connectivity model: the proportion of recruits immigrating from warmer locations. We have confirmed that this metric correlates with actual coral cover changes throughout the region, based on published reef survey data from the 1970s to early 2000s. The new metric allows planning assisted gene flow interventions to facilitate adaptation of specific coral populations.

scholarly journals Coral Reef Recovery in the Mexican Caribbean after 2005 Mass Coral Mortality—Potential Drivers

Diversity ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 338
Author(s):  
Xochitl E. Elías Ilosvay ◽  
Ameris I. Contreras-Silva ◽  
Lorenzo Alvarez-Filip ◽  
Christian Wild
Keyword(s):  
Coral Cover ◽  
Geographical Location ◽  
Relative Effect ◽  
Significant Loss ◽  
Coral Mortality ◽  
Hard Coral ◽  
Mexican Caribbean ◽  
Algae Growth ◽  
Reef Recovery ◽  
Coral Recovery

In 2005, an extreme heatwave hit the Wider Caribbean, followed by 13 hurricanes (including hurricanes Emily and Wilma) that caused significant loss in hard coral cover. However, the drivers of the potential recovery are yet to be fully understood. Based on recent findings in the literature of coral cover recovery in the Mexican Caribbean after the mass bleaching event and associated hurricanes in 2005, this study analyzed, through random-effects meta-analysis, the hard coral and macroalgae benthic development and potential drivers of change between 2005 and 2016 in the Mexican Caribbean. Therefore, we tested the relative effect of sea surface temperature (SST), chlorophyll-a water concentration, coastal human population development, reef distance to shore, and geographical location on both hard coral and macroalgae cover over time. Findings revealed increases of both hard coral (by 6%) and algae cover (by ca. 14%, i.e., almost three times the increase of corals) over 12 years. Although our findings confirm the partial coral recovery after the 2005 Caribbean mass coral mortality event, they also indicate rapid colonization of algae across the region. Surprisingly, only SST correlated negatively with changes in coral cover. Contrary to expectations, there was a significantly greater algae cover increase in the Central section of the Mexican Caribbean, which is characterized by a low population density. However, a constant discharge of nutrient-rich freshwater may have facilitated algae growth there. This study reports partial regional reef recovery, but it also indicates that local factors, particularly eutrophication, facilitate algae growth at a speed that is much faster than coral recovery.

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