Evaluation of coral reef carbonate production models at a global scale

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.

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Evaluation of coral reef carbonate production models at a global scale

Biogeosciences Discussions ◽

10.5194/bgd-11-12895-2014 ◽

2014 ◽

Vol 11 (9) ◽

pp. 12895-12936

Author(s):

N. S. Jones ◽

A. Ridgwell ◽

E. J. Hendy

Keyword(s):

Coral Reef ◽

Predictive Power ◽

Numerical Models ◽

Coral Cover ◽

Light Availability ◽

Global Scale ◽

Carbonate Production ◽

Production Models ◽

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 essential for understanding how carbonate deposition responds to environmental conditions including future atmospheric CO2 concentrations, but these models must first be evaluated in terms of their 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, by comparing carbonate budget outputs with independent estimates. We also compile available global data on reef calcification to produce an observation-based dataset for the model evaluation. 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). None of the four models correlated with independent rate estimates of whole reef calcification. The temperature-only based approach was the only model output 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 modeling approach, accounting for population dynamics in terms of mortality and recruitment and hence coral cover, 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.

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Global declines in coral reef calcium carbonate production under ocean acidification and warming

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2015265118 ◽

2021 ◽

Vol 118 (21) ◽

pp. e2015265118

Author(s):

Christopher E. Cornwall ◽

Steeve Comeau ◽

Niklas A. Kornder ◽

Chris T. Perry ◽

Ruben van Hooidonk ◽

...

Keyword(s):

Coral Reef ◽

Calcium Carbonate ◽

Coral Reefs ◽

Scale Effects ◽

Coral Cover ◽

Meta Analysis ◽

Global Scale ◽

Ocean Warming ◽

Carbonate Production ◽

Near Term

Ocean warming and acidification threaten the future growth of coral reefs. This is because the calcifying coral reef taxa that construct the calcium carbonate frameworks and cement the reef together are highly sensitive to ocean warming and acidification. However, the global-scale effects of ocean warming and acidification on rates of coral reef net carbonate production remain poorly constrained despite a wealth of studies assessing their effects on the calcification of individual organisms. Here, we present global estimates of projected future changes in coral reef net carbonate production under ocean warming and acidification. We apply a meta-analysis of responses of coral reef taxa calcification and bioerosion rates to predicted changes in coral cover driven by climate change to estimate the net carbonate production rates of 183 reefs worldwide by 2050 and 2100. We forecast mean global reef net carbonate production under representative concentration pathways (RCP) 2.6, 4.5, and 8.5 will decline by 76, 149, and 156%, respectively, by 2100. While 63% of reefs are projected to continue to accrete by 2100 under RCP2.6, 94% will be eroding by 2050 under RCP8.5, and no reefs will continue to accrete at rates matching projected sea level rise under RCP4.5 or 8.5 by 2100. Projected reduced coral cover due to bleaching events predominately drives these declines rather than the direct physiological impacts of ocean warming and acidification on calcification or bioerosion. Presently degraded reefs were also more sensitive in our analysis. These findings highlight the low likelihood that the world’s coral reefs will maintain their functional roles without near-term stabilization of atmospheric CO2 emissions.

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3D HABITAT COMPLEXITY OF CORAL REEFS IN THE NORTHWESTERN HAWAIIAN ISLANDS IS DRIVEN BY CORAL ASSEMBLAGE STRUCTURE

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-2-w10-61-2019 ◽

2019 ◽

Vol XLII-2/W10 ◽

pp. 61-67 ◽

Cited By ~ 3

Author(s):

J. H. R. Burns ◽

A. Fukunaga ◽

K. H. Pascoe ◽

A. Runyan ◽

B. K. Craig ◽

...

Keyword(s):

Coral Reef ◽

Habitat Complexity ◽

Coral Cover ◽

Light Availability ◽

Structural Complexity ◽

Assemblage Structure ◽

Natural Environments ◽

Live Coral ◽

Ecological Processes ◽

Coral Assemblage

<p><strong>Abstract.</strong> Corals act as ecosystem engineers by secreting structurally complex calcium carbonate skeletons on the benthic substrate that provide habitat for a diverse array of associated reef organisms. Communities of living corals create large and dynamic benthic structures that directly affect ecological parameters such as habitat provisioning and light availability, thus influencing overall ecosystem function. Despite the important role 3D structural complexity plays in ecosystem biodiversity and productivity, the field of coral ecology has lacked accessibility to practical technology capable of quantifying 3D characteristics of underwater habitats. Advancements in the field of computer vision has led to Structure-from-Motion (SfM) photogrammetry, which provides a simple and cost-effective method for creating high-resolution and spatially accurate 3D reconstructions of natural environments. Integrating SfM approaches into coral reef research and monitoring has provided useful insight into the relationship between 3D habitat complexity and ecological processes. In this study, we examined the relationships among 2D estimates of live coral cover and several metrics of 3D habitat structural complexity among eleven long-term monitoring sites at French Frigate Shoals. Our findings show that coral assemblage structure acts as a significant driver of 3D structural complexity of coral reef habitats at this atoll. This study highlights the importance of diverse and abundant coral assemblages in supporting structurally complex coral reef habitats and provides a framework for future investigations into the ecological role of various coral morphotypes.</p>

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Global distribution of root climbers is positively associated with precipitation and negatively associated with seasonality

Journal of Tropical Ecology ◽

10.1017/s0266467413000308 ◽

2013 ◽

Vol 29 (4) ◽

pp. 357-360 ◽

Cited By ~ 14

Author(s):

Jaqueline Durigon ◽

Sandra Milena Durán ◽

Ernesto Gianoli

Keyword(s):

Light Availability ◽

Global Scale ◽

High Irradiance ◽

Mean Annual Precipitation ◽

Low Light ◽

Data Set ◽

High Precipitation ◽

Root Climber ◽

Increasing Temperature ◽

The Tropics

Abstract:Root climbers constitute a distinctive group within climbing plants and some evidence suggests that they are associated with high precipitation and low light availability at local scales, which is in contrast with general patterns of liana distribution in the tropics. The influence of precipitation and seasonality on the occurrence of root climbers was evaluated both globally and in the tropics. The presence/absence of root climbers was recorded in 174 sites of Alwyn H. Gentry Forest Transect Data Set. The effects of mean annual precipitation and dry-season length (and temperature) on their occurrence were analysed using logistic regressions. Root climbers were significantly more frequent in sites with greater precipitation and reduced seasonality. Increasing temperature reduced root-climber occurrence in tropical sites, but this effect was marginally significant at a global scale. Dry and open habitats appear unsuitable for root climbers. This can be explained by the susceptibility to desiccation of adventitious roots and/or the low acclimation ability of these climbers to high irradiance.

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Drivers and predictions of coral reef carbonate budget trajectories

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.2533 ◽

2017 ◽

Vol 284 (1847) ◽

pp. 20162533 ◽

Cited By ~ 27

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.

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Coral reef condition in several dive points around Bunaken Island, North Sulawesi

AQUATIC SCIENCE & MANAGEMENT ◽

10.35800/jasm.0.0.2014.7306 ◽

2014 ◽

pp. 44

Author(s):

Robert Towoliu

Keyword(s):

Coral Reef ◽

Coral Cover ◽

Integrated Management ◽

Good Condition ◽

Live Coral ◽

Core Zone ◽

Integrated Management System ◽

North Sulawesi ◽

Live Coral Cover ◽

Reef Condition

In order to know the coral reef conditions at several diving points around Bunaken Island, three dive locations (Ron’s point, Lekuan, and Tawara) were chosen as representative locations receiving pressures from snorkeling and SCUBA diving activities, while core zone was representative of location for no diving and fishing activities. Results showed that location with diving activities had live coral cover ranging from 16.89% to 45.78% at 3 and 10m depths, with condition range of bad to moderate, while the location for no diving and fishing activities (core zone) had live coral cover of 55.03% at 3m and 58.15% at 10m, respectively, with good condition category. The present study indicated that the diving activities have affected the coral reef condition, so that a sustainable integrated management system is needed to use the marine ecotourism potency without degrading the coral reef condition in Bunaken Island. Untuk mengetahui kondisi terumbu karang di beberapa lokasi penyelaman di Pulau Bunaken, tiga lokasi penyelaman(Ron’s point, Lekuan, dan Tawara) dipilih mewakili lokasi dengan tekanan aktivitas penyelaman snorkeling maupun SCUBA, sedangkan satu lokasi lainnya yaitu zona inti dipilih mewakili lokasi tanpa aktivitas penyelaman maupun aktivitas penangkapan ikan. Hasil penelitian ini memperlihatkan bahwa lokasi dengan tekanan aktivitas penyelaman memiliki prosentase tutupan karang batu/hidup berkisar antara 16,89% - 45,78% pada kedalaman 3 dan 10m, dengan kategori kondisi terumbu karang buruk sampai cukup, sedangkan pada lokasi yang tidak memiliki aktivitas penyelaman memiliki prosentase tutupan karang batu/hidup sebesar 53,03% pada 3m dan 58,15% pada 10m dengan kategori kondisi terumbu karang adalah baik. Hasil penelitian ini mengindikasikan bahwa aktivitas penyelaman snorkeling maupun SCUBA berdampak pada kondisi terumbu karang di Pulau Bunaken, sehingga sangat diperlukan system pengelolaan yang terpadu dan berkesinambungan dalam memanfaatkan secara maksimal potensi ekowisata bahari tanpa merusak ekosistem terumbu karang di Pulau Bunaken.

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Prominence of environmental and anthropogenic agents on the occurrence of coral reef bleaching syndrome and coral diseases

Medycyna Weterynaryjna ◽

10.21521/mw.6139 ◽

2024 ◽

Vol 74 (10) ◽

pp. 6139-2024

Author(s):

MICHAŁ SCHULZ ◽

ALEKSANDRA ŁOŚ ◽

PATRYCJA SKOWRONEK ◽

ANETA STRACHECKA

Keyword(s):

Coral Reef ◽

Coral Reefs ◽

Oil Spills ◽

Global Scale ◽

Ecological Processes ◽

Coral Diseases ◽

Rapid Changes ◽

Anthropogenic Threats ◽

Negative Factors ◽

Main Relationship

Coral reefs are the most productive ecosystems on Earth. They ensure the conservation of biodiversity and are a live habitat for 25% of all marine organisms. The main relationship on the coral reef is the symbiosis between corals and algae from the genus Symbiodinium (commonly called zooxanthellae). The authors of this publication have characterized and described the factors limiting the occurrence of coral reefs, including: water temperature, salinity, access to sunlight, contamination, physicochemical and hydromechanical parameters of water. Moreover anthropogenic threats to coral reefs have been specified, including diving tourism, ecological disasters (e.g. oil spills) and the development of marine aquaristics. Rapid changes in the basic living conditions are dangerous for corals and their symbionts and may cause the unsuitability of the new environment resulting in diseases such as coral bleaching. Corals bleaching is a disease associated with the break of the coral and algae relationship which results in a coral reef death on a global scale. Awareness of these negative factors, often related to human activity, may allow us to better understand the ecological processes that are the basis of reef functioning and might enable us to prevent and oppose to the changes and ecological recessions of coral reefs.

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Predictive and Descriptive CoMFA Models: The Effect of Variable Selection

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207321666180212162028 ◽

2018 ◽

Vol 21 (2) ◽

pp. 117-124 ◽

Cited By ~ 4

Author(s):

Bakhtyar Sepehri ◽

Nematollah Omidikia ◽

Mohsen Kompany-Zareh ◽

Raouf Ghavami

Keyword(s):

Variable Selection ◽

Predictive Power ◽

Selection Method ◽

Data Sets ◽

Data Set ◽

Comfa Model ◽

Variable Selection Method

Aims & Scope: In this research, 8 variable selection approaches were used to investigate the effect of variable selection on the predictive power and stability of CoMFA models. Materials & Methods: Three data sets including 36 EPAC antagonists, 79 CD38 inhibitors and 57 ATAD2 bromodomain inhibitors were modelled by CoMFA. First of all, for all three data sets, CoMFA models with all CoMFA descriptors were created then by applying each variable selection method a new CoMFA model was developed so for each data set, 9 CoMFA models were built. Obtained results show noisy and uninformative variables affect CoMFA results. Based on created models, applying 5 variable selection approaches including FFD, SRD-FFD, IVE-PLS, SRD-UVEPLS and SPA-jackknife increases the predictive power and stability of CoMFA models significantly. Result & Conclusion: Among them, SPA-jackknife removes most of the variables while FFD retains most of them. FFD and IVE-PLS are time consuming process while SRD-FFD and SRD-UVE-PLS run need to few seconds. Also applying FFD, SRD-FFD, IVE-PLS, SRD-UVE-PLS protect CoMFA countor maps information for both fields.

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Rapid multi-directed cholinergic transmission in the central nervous system

Nature Communications ◽

10.1038/s41467-021-21680-9 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Santhosh Sethuramanujam ◽

Akihiro Matsumoto ◽

Geoff deRosenroll ◽

Benjamin Murphy-Baum ◽

J Michael McIntosh ◽

...

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Ganglion Cells ◽

Release Site ◽

Amacrine Cells ◽

Global Scale ◽

Cholinergic Transmission ◽

Data Set ◽

The Central Nervous System ◽

Synaptic Mechanisms

AbstractIn many parts of the central nervous system, including the retina, it is unclear whether cholinergic transmission is mediated by rapid, point-to-point synaptic mechanisms, or slower, broad-scale ‘non-synaptic’ mechanisms. Here, we characterized the ultrastructural features of cholinergic connections between direction-selective starburst amacrine cells and downstream ganglion cells in an existing serial electron microscopy data set, as well as their functional properties using electrophysiology and two-photon acetylcholine (ACh) imaging. Correlative results demonstrate that a ‘tripartite’ structure facilitates a ‘multi-directed’ form of transmission, in which ACh released from a single vesicle rapidly (~1 ms) co-activates receptors expressed in multiple neurons located within ~1 µm of the release site. Cholinergic signals are direction-selective at a local, but not global scale, and facilitate the transfer of information from starburst to ganglion cell dendrites. These results suggest a distinct operational framework for cholinergic signaling that bears the hallmarks of synaptic and non-synaptic forms of transmission.

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