Associations between Benthic Cover and Habitat Complexity Metrics Obtained from 3D Reconstruction of Coral Reefs at Different Resolutions

Quantifying the three-dimensional (3D) habitat structure of coral reefs is an important aspect of coral reef monitoring, as habitat architecture affects the abundance and diversity of reef organisms. Here, we used photogrammetric techniques to generate 3D reconstructions of coral reefs and examined relationships between benthic cover and various habitat metrics obtained at six different resolutions of raster cells, ranging from 1 to 32 cm. For metrics of 3D structural complexity, fractal dimension, which utilizes information on 3D surface areas obtained at different resolutions, and vector ruggedness measure (VRM) obtained at 1-, 2- or 4-cm resolution correlated well with benthic cover, with a relatively large amount of variability in these metrics being explained by the proportions of corals and crustose coralline algae. Curvature measures were, on the other hand, correlated with branching and mounding coral cover when obtained at 1-cm resolution, but the amount of variability explained by benthic cover was generally very low when obtained at all other resolutions. These results show that either fractal dimension or VRM obtained at 1-, 2- or 4-cm resolution, along with curvature obtained at 1-cm resolution, can effectively capture the 3D habitat structure provided by specific benthic organisms.

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Microhabitats of sharknose goby (Elacatinus evelynae) cleaning stations and their links with cleaning behaviour

Coral Reefs ◽

10.1007/s00338-021-02105-x ◽

2021 ◽

Author(s):

Kathryn E. Whittey ◽

Katie Dunkley ◽

Grace C. Young ◽

Jo Cable ◽

Sarah E. Perkins

Keyword(s):

Coral Reefs ◽

Coral Cover ◽

Marine Ecosystem ◽

Three Dimensional ◽

Structural Complexity ◽

Live Coral ◽

Cleaner Fish ◽

Habitat Features ◽

Anthropogenic Threats ◽

Cleaning Stations

AbstractCoral reefs are renowned for the complexity of their habitat structures and their resulting ability to host more species per unit area than any another marine ecosystem. Dedicated cleaner fish, which acquire all their food resources through client interactions, rely on both the habitat structures (by using topological cleaning stations) and the wide diversity of fish species available on coral reefs, to function. As a result of natural and anthropogenic threats, coral reef habitat structures and their complexity are being lost—despite this threat it is unclear how important reef geometry is to key ecological interactions, like cleaning. Using an established Caribbean reef study site, three-dimensional constructions of discrete coral heads were used to investigate how fine-scale structural complexity traits (structural complexity—measured by rugosity and vector dispersion—height, volume, surface area, percentage live coral cover and refuge availability) relate to cleaner occupancy, abundance and their cleaning interactions with clients. Coral height was a particularly important trait for cleaning, correlating with both the occurrence of cleaning stations on a reef, and with increased cleaning durations and reduced cleaning frequencies/rates. Cleaning stations were also more structurally complex than non-cleaning coral heads, and the increased availability of uneven surfaces (creating cracks and crevices) and refuge availability linked with increased cleaning durations/rates. By understanding habitat features important to cleaner fish on a typical Caribbean fringing reef, we can gain a better understanding of how important reef geometry might be for governing the occurrence and dynamics of such mutualisms.

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Effect of 3D printer enabled surface morphology and composition on coral growth in artificial reefs

Rapid Prototyping Journal ◽

10.1108/rpj-07-2020-0165 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Ilse Valenzuela Matus ◽

Jorge Lino Alves ◽

Joaquim Góis ◽

Augusto Barata da Rocha ◽

Rui Neto ◽

...

Keyword(s):

Additive Manufacturing ◽

Chemical Composition ◽

Chemical Elements ◽

Three Dimensional ◽

Coral Growth ◽

Coralline Algae ◽

Textured Surface ◽

Crustose Coralline Algae ◽

Statistical Parameters ◽

Content Type

Purpose The purpose of this paper is to prove and qualify the influence of textured surface substrates morphology and chemical composition on the growth and propagation of transplanted corals. Use additive manufacturing and silicone moulds for converting three-dimensional samples into limestone mortar with white Portland cement substrates for coral growth. Design/methodology/approach Tiles samples were designed and printed with different geometries and textures inspired by nature marine environment. Commercial coral frag tiles were analysed through scanning electron microscopy (SEM) to identify the main chemical elements. Raw materials and coral species were selected. New base substrates were manufactured and deployed into a closed-circuit aquarium to monitor the coral weekly evolution process and analyse the results obtained. Findings Experimental results provided positive statistical parameters for future implementation tests, concluding that the intensity of textured surface, interfered favourably in the coralline algae biofilm growth. The chemical composition and design of the substrates were determinant factors for successful coral propagation. Recesses and cavities mimic the natural rocks aspect and promoted the presence and interaction of other species that favour the richness of the ecosystem. Originality/value Additive manufacturing provided an innovative method of production for ecology restoration areas, allowing rapid prototyping of substrates with high complexity morphologies, a critical and fundamental attribute to guarantee coral growth and Crustose Coralline Algae. The result of this study showed the feasibility of this approach using three-dimensional printing technologies.

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The hidden army: corallivorous crown-of-thorns seastars can spend years as herbivorous juveniles

Biology Letters ◽

10.1098/rsbl.2019.0849 ◽

2020 ◽

Vol 16 (4) ◽

pp. 20190849 ◽

Cited By ~ 7

Author(s):

Dione J. Deaker ◽

Antonio Agüera ◽

Huang-An Lin ◽

Corinne Lawson ◽

Claire Budden ◽

...

Keyword(s):

Coral Reefs ◽

Exponential Growth ◽

Black Box ◽

Coralline Algae ◽

Crustose Coralline Algae ◽

Major Threat ◽

Asymptotic Size ◽

The Impact

Crown-of-thorns seastar (COTS) outbreaks are a major threat to coral reefs. Although the herbivorous juveniles and their switch to corallivory are key to seeding outbreaks, they remain a black box in our understanding of COTS. We investigated the impact of a delay in diet transition due to coral scarcity in cohorts reared on crustose coralline algae for 10 months and 6.5 years before being offered coral. Both cohorts achieved an asymptotic size (16–18 mm diameter) on algae and had similar exponential growth on coral. After 6.5 years of herbivory, COTS were competent coral predators. This trophic and growth plasticity results in a marked age–size disconnect adding unappreciated complexity to COTS boom–bust dynamics. The potential that herbivorous juveniles accumulate in the reef infrastructure to seed outbreaks when favourable conditions arise has implications for management of COTS populations.

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Crustose coralline algae increased framework and diversity on ancient coral reefs

PLoS ONE ◽

10.1371/journal.pone.0181637 ◽

2017 ◽

Vol 12 (8) ◽

pp. e0181637 ◽

Cited By ~ 7

Author(s):

Anna Weiss ◽

Rowan C. Martindale

Keyword(s):

Coral Reefs ◽

Coralline Algae ◽

Crustose Coralline Algae

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Coral Reef Degradation Due to ‘Ship Grounding’ in Indonesia: Case Study of Ship Aground in Bangka-Belitung Waters by Mother Vessel MV Lyric Poet

Jurnal Ilmiah Perikanan dan Kelautan ◽

10.20473/jipk.v12i2.17947 ◽

2020 ◽

Vol 12 (2) ◽

pp. 263

Author(s):

Idris Idris ◽

Neviaty P. Zamani ◽

Suharsono Suharsono ◽

Fakhrurrozi Fakhrurrozi

Keyword(s):

Coral Reef ◽

Coral Reefs ◽

Coral Species ◽

Coral Cover ◽

Conservation Status ◽

Three Dimensional ◽

Live Coral ◽

Hard Coral ◽

Lyric Poet ◽

Ship Grounding

HighlightDamage to coral reefs by ship aground is twice the area of a football fieldFound four zones of damage including runoff, dune, blow and dispersalMortality of live coral and other benthic biota ranges from 75-100% in the affected locationThe form of damaged live coral growth is predominantly slow growing.Eight hard coral species were found on the IUCN-Redlist list with a vulnerable status.AbstractShip grounding on coral reefs often results in physical and biological damage, including dislodging and removal of corals from reefs, destruction of coral skeletons, erosion and removal of sediment deposits, and loss of three-dimensional complexity. Indonesia, as an archipelagic country, is very vulnerable to various pressures; for example, the case of ship grounding is a great concern of scientists, managers, divers, and sailors themselves. Most of the damage is very severe. The purpose of the research conducted is to identify the condition of the live coral cover, mapping the type and extent of coral reef damage, affected coral species, their conservation status, and to quantify the extent of the area of coral reef damage. Measuring the extent of damage to coral reef ecosystems using the fishbone method, while the level of damage and its impact was measured using the Underwater Photo Transect (UPT) and belt transect method. The event of the grounding of the MV Lyric Poet on the Bangka Waters, Bangka-Belitung Province, has caused damage to the coral reef ecosystem. There are four damage zones identified, i.e., trajectory, mound, propeller, and dispersion zone. Corals are damaged with a total area of 13.540m2; equivalent to twice that of an international football field. Diversity of hard coral found as many as 49 species included in the CITES-Appendix II. A total of eight protected species are included in the IUCN Red List with extinction-prone status.

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CRUSTOSE CORALLINE ALGAE INCREASE FRAMEWORK AND DIVERSITY ON ANCIENT CORAL REEFS

10.1130/abs/2016am-281530 ◽

2016 ◽

Author(s):

Anna M. Weiss ◽

◽

Rowan Martindale

Keyword(s):

Coral Reefs ◽

Coralline Algae ◽

Crustose Coralline Algae

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Integrating Three-Dimensional Benthic Habitat Characterization Techniques into Ecological Monitoring of Coral Reefs

Journal of Marine Science and Engineering ◽

10.3390/jmse7020027 ◽

2019 ◽

Vol 7 (2) ◽

pp. 27 ◽

Cited By ~ 12

Author(s):

Atsuko Fukunaga ◽

John Burns ◽

Brianna Craig ◽

Randall Kosaki

Keyword(s):

Fractal Dimension ◽

Coral Reefs ◽

Three Dimensional ◽

Ecological Monitoring ◽

Benthic Habitat ◽

Fish Assemblage Structure ◽

Benthic Habitats ◽

Single Measure ◽

Curvature Measures

Long-term ecological monitoring of reef fish populations often requires the simultaneous collection of data on benthic habitats in order to account for the effects of these variables on fish assemblage structure. Here, we described an approach to benthic surveys that uses photogrammetric techniques to facilitate the extraction of quantitative metrics for characterization of benthic habitats from the resulting three-dimensional (3D) reconstruction of coral reefs. Out of 92 sites surveyed in the Northwestern Hawaiian Islands, photographs from 85 sites achieved complete alignment and successfully produced 3D reconstructions and digital elevation models (DEMs). Habitat metrics extracted from the DEMs were generally correlated with one another, with the exception of curvature measures, indicating that complexity and curvature measures should be treated separately when quantifying the habitat structure. Fractal dimension D64, calculated by changing resolutions of the DEMs from 1 cm to 64 cm, had the best correlations with other habitat metrics. Fractal dimension was also less affected by changes in orientations of the models compared to surface complexity or slope. These results showed that fractal dimension can be used as a single measure of complexity for the characterization of coral reef habitats. Further investigations into metrics for 3D characterization of habitats should consider relevant spatial scales and focus on obtaining variables that can complement fractal dimension in the characterization of reef habitats.

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Factors Affecting Coral Recruitment and Calcium Carbonate Accretion Rates on a Central Pacific Coral Reef

10.26686/wgtn.17057996 ◽

2021 ◽

Author(s):

◽

Franziska Elmer

Keyword(s):

Coral Reef ◽

Calcium Carbonate ◽

Coral Reefs ◽

Benthic Community ◽

Coral Cover ◽

Coralline Algae ◽

Benthic Organisms ◽

Coral Recruitment ◽

Central Pacific ◽

Accretion Rates

<p>Coral recruitment and calcium carbonate (CaCO₃) accretion are fundamental processes that help maintain coral reefs. Many reefs worldwide have experienced degradation, including a decrease in coral cover and biodiversity. Successful coral recruitment helps degraded reefs to recover, while CaCO₃ accretion by early successional benthic organisms maintains the topographic complexity of a coral reef system. It is therefore important to understand the processes that affect coral recruitment and CaCO₃ accretion rates in order to understand how coral reefs recover from disturbances. The aim of this thesis was to determine how biophysical forcing factors affect coral recruitment, calcification and bioerosion on a pristine coral reef. I used artificial settlement tiles to measure coral recruitment and CaCO₃ accretion at ten sites (four on the fore reef, four on the Western Reef Terrace and two at the Entrance Channel) at Palmyra Atoll. Fungia skeletons and pieces of dead coral rock were used to measure bioerosion rates, which were combined with the CaCO₃ accretion rates to obtain a net CaCO₃ budget of the reef substratum. Interactions between coral recruits and other benthic organisms on the settlement tiles were recorded to determine the settlement preferences and competitive strength of coral recruits. The settlement preference of Pocillopora damicornis for divots shaped like steephead and bumphead parrotfish bites marks was determined by adding P. damicornis larvae to a container with a settlement tile with the aforementioned divots. I found that coral recruitment and CaCO₃ accretion are influenced by biophysical forcing factors. Most pocilloporids likely recruit close to their parents while the origin of poritid larvae is much more distant. Pocilloporid recruitment rates were also significantly correlated with the successional stage of the benthic community on the settlement tiles, especially the cover of biofilm and bryozoa. Biofilm and crustose coralline algae (CCA) were preferred as settlement substrata by coral larvae, however both pocilloporids and poritids settled on a large number of different benthic substrata. P. damicornis larvae showed a significant settlement preference for divots shaped like parrotfish bite marks over a flat settlement surface. Coral recruits were good competitors against encrusting algae but were often outcompeted by filamentous and upright algae. Settlement tiles were almost entirely colonised by benthic organisms within three to twelve months of deployment. The mass of CaCO₃ deposited onto the settlement tiles negatively correlated with herbivore grazing pressure on the benthic community. Bioerosion rates within pieces of coral (internal bioerosion) increased over time but overall bioerosion rates (internal and external) rarely exceeded CaCO₃ deposition by CCA. My results show how variability in biophysical forcing factors leads to natural variation in coral recruitment and CaCO₃ accretion. This thesis highlights the importance of measuring herbivore grazing, CCA and turf algae cover to gain a better understanding of reef resilience. I conclude that models constructed for Caribbean reefs may not be suited to predict resilience in Pacific reefs and that within the Pacific, two different kinds of resilience models need to be constructed, one for human-inhabited coral reefs and one for uninhabited coral reefs.</p>

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Low recruitment due to altered settlement substrata as primary constraint for coral communities under ocean acidification

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.1536 ◽

2017 ◽

Vol 284 (1862) ◽

pp. 20171536 ◽

Cited By ~ 21

Author(s):

Katharina E. Fabricius ◽

Sam H. C. Noonan ◽

David Abrego ◽

Lindsay Harrington ◽

Glenn De'ath

Keyword(s):

Coral Reefs ◽

Ocean Acidification ◽

Field Experiments ◽

Later Life ◽

Coralline Algae ◽

Life Stages ◽

Crustose Coralline Algae ◽

Coral Recruitment ◽

Recovery Potential ◽

Coral Communities

The future of coral reefs under increasing CO 2 depends on their capacity to recover from disturbances. To predict the recovery potential of coral communities that are fully acclimatized to elevated CO 2 , we compared the relative success of coral recruitment and later life stages at two volcanic CO 2 seeps and adjacent control sites in Papua New Guinea. Our field experiments showed that the effects of ocean acidification (OA) on coral recruitment rates were up to an order of magnitude greater than the effects on the survival and growth of established corals. Settlement rates, recruit and juvenile densities were best predicted by the presence of crustose coralline algae, as opposed to the direct effects of seawater CO 2 . Offspring from high CO 2 acclimatized parents had similarly impaired settlement rates as offspring from control parents. For most coral taxa, field data showed no evidence of cumulative and compounding detrimental effects of high CO 2 on successive life stages, and three taxa showed improved adult performance at high CO 2 that compensated for their low recruitment rates. Our data suggest that severely declining capacity for reefs to recover, due to altered settlement substrata and reduced coral recruitment, is likely to become a dominant mechanism of how OA will alter coral reefs.

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