Life Sciences Commons^™

Further Flattening Of A Degraded, Turbid Reef System Following A Severe Coral Bleaching Event, Andrew G. Bauman, Fraser A. Januchowski-Hartley, Aaron Teo, Peter A. Todd

Marine & Environmental Sciences Faculty Articles

Increasing incidence of severe coral bleaching events caused by climate change is contributing to extensive coral losses, shifts in species composition and widespread declines in the physical structure of coral reef ecosystems. With these ongoing changes to coral communities and the concomitant flattening of reef structural complexity, understanding the links between coral composition and structural complexity in maintaining ecosystem functions and processes is of critical importance. Here, we document the impacts of the 2016 global-scale coral bleaching event on seven coral reefs in Singapore; a heavily degraded, turbid reef system. Using a combination of field-based surveys, we examined changes in …

Comparison Of Recent Survey Techniques For Estimating Benthic Cover On Caribbean Mesophotic Reefs, Joseph R. Pawlik, Roy A. Armstrong, Stephanie Farrington, John Reed, Sara Rivero-Calle, Hanumant Singh, Brian K. Walker, Jason White

Marine & Environmental Sciences Faculty Articles

Highly divergent estimates of benthic cover of sponges have been reported for Caribbean mesophotic reefs (90-100 m) based on quadrat point-intercept data collection using 2 methods: visual surveys conducted in situ by technical divers, and analyses of photographs taken by unmanned underwater vehicles (UUVs). The second method has been criticized for potential errors from image distortion caused by variable camera angle relative to the substratum, but without a broader comparison of both methods. We find that studies that have used the UUV-based method are advantageous for a number of reasons, most importantly: (1) access to the full mesophotic zone, (2) …

Element Contamination In Port Everglades – Preparing For Ecological Impacts, Laura White

All HCAS Student Capstones, Theses, and Dissertations

Port dredging is of economic importance worldwide but its impacts to the marine environment through the remobilization of elemental contaminants are not well understood. A massive deepening and widening of Port Everglades, Florida, will begin in 2023. Contaminated sediment disturbed during the dredging process could be released and prove to be harmful to three coral reef tracks located beginning 1.5 miles away from the port. This study focused on identifying and quantifying 14 different trace elements: arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), manganese (Mn), molybdenum (Mo), nickel (Ni), selenium (Se), tin (Sn), …

Survivorship And Growth In Staghorn Coral (Acropora Cervicornis) Outplanting Projects In The Florida Keys National Marine Sanctuary, Matt Ware, Eliza N. Garfield, Ken Nedimyer, Jessica Levy, Les Kaufman, William F. Precht, R. Scott Winters, Steven Miller

Marine & Environmental Sciences Faculty Articles

Significant population declines in Acropora cervicornis and A. palmata began in the 1970s and now exceed over 90%. The losses were caused by a combination of coral disease and bleaching, with possible contributions from other stressors, including pollution and predation. Reproduction in the wild by fragment regeneration and sexual recruitment is inadequate to offset population declines. Starting in 2007, the Coral Restoration Foundation™ evaluated the feasibility of outplanting A. cervicornis colonies to reefs in the Florida Keys to restore populations at sites where the species was previously abundant. Reported here are the results of 20 coral outplanting projects …

The Microscopic Threat With A Macroscopic Impact: Microplastics Along The Southeast Florida Reef Tract, Emma Wightman

HCNSO Student Theses and Dissertations

Microplastics have been found in large quantities in marine water samples and biota around the world. These microplastics, when present in the marine environment, decrease water quality and negatively impact marine life. This research quantified and classified marine plastic pollution along the Southeast Florida Reef Tract (SEFRT), in order to understand how this plastic is entering the ocean and the scope of the microplastic contamination in the northern SEFRT. Surface and bottom water samples were collected at 7 sites along the SEFRT for 6 months, filtered, and microscopically analyzed for microplastic content and composition using Fourier-transform infrared spectrophotometry (FTIR). Classification …

A Revised Holocene Coral Sea-Level Database From The Florida Reef Tract, Usa, Anastasios Stathakopoulos, Bernhard Riegl, Lauren T. Toth

Marine & Environmental Sciences Faculty Articles

The coral reefs and mangrove habitats of the south Florida region have long been used in sea-level studies for the western Atlantic because of their broad geographic extent and composition of sea-level tracking biota. The data from this region have been used to support several very different Holocene sea-level reconstructions (SLRs) over the years. However, many of these SLRs did not incorporate all available coral-based data, in part because detailed characterizations necessary for inclusion into sea-level databases were lacking. Here, we present an updated database comprised of 303 coral samples from published sources that we extensively characterized for the first …

Spatial And Temporal Trends Of Southeastern Florida's Octocoral Comunity, Alexandra Hiley

HCNSO Student Theses and Dissertations

In the Caribbean, local and global stressors have driven significant declines in scleractinian coral cover up to 80% in only three decades. Following these declines, phase shifts in benthic community composition have been reported. Shifts towards macroalgal dominance has been the most widely observed case, however, shifts towards octocoral and sponge dominance have also been reported. In Florida, USA, the Florida Reef Tract is an extensive barrier reef system that contains diverse assemblages of corals, sponges, fish, and other taxa. The Southeast Florida Reef Tract (SEFRT) within the Southeast Florida Coral Reef Conservation Area is the northern portion of this …

Fear Effects Associated With Predator Presence And Habitat Structure Interact To Alter Herbivory On Coral Reefs, Andrew G. Bauman, Jovena C. L. Seah, Fraser A. Januchowski-Hartley, Andrew S. Hoey, Jenny Fong, Peter A. Todd

Marine & Environmental Sciences Faculty Articles

Non-consumptive fear effects are an important determinant of foraging decisions by consumers across a range of ecosystems. However, how fear effects associated with the presence of predators interact with those associated with habitat structure remain unclear. Here, we used predator fish models (Plectropomus leopardus) and experimental patches of the macroalga Sargassum ilicifolium of varying densities to investigate how predator- and habitat-associated fear effects influence herbivory on coral reefs. We found the removal of macroalgal biomass (i.e. herbivory) was shaped by the interaction between predator- and habitat-associated fear effects. Rates of macroalgal removal declined with increasing macroalgal density, likely …

Population Dynamics And Genotypic Richness Of The Threatened Acropora Spp. And Their Hybrid In The U.S. Virgin Islands, Hannah F. Nylander-Asplin

HCNSO Student Theses and Dissertations

Since the 1980’s, there has been an unprecedented decline in the reef-building Caribbean corals, Acropora cervicornis and A. palmata, which has led to their listing as “threatened” under the U.S Endangered Species Act. Despite this protective status, these Acropora species continue to experience declines primarily attributed to disease, global climate change, and storm damage. Recent evidence suggests the hybrid of these threatened species (A. prolifera) is found at abundances similar to or higher than the parental species at many sites throughout the Caribbean. However, there is still much that is unknown as to how and why hybrids may …

Spatiotemporal Change In The Benthic Community Of Southeast Florida, Nicholas P. Jones

HCNSO Student Theses and Dissertations

High-latitude reefs have been postulated as refugia, centers for resilience or the first areas to undergo re-organization under climate change. The Southeast Florida Reef Tract (SEFRT) is a high-latitude reef system (>25 °N) running parallel to the highly urbanized coastline of southeast Florida. With a benthic community comprised of a mixture of coral reef associated assemblages, the SEFRT is towards the northern limit of stony coral cover due to temperature constraints. This study analyzed spatial variations in benthic cover, spatiotemporal changes in the benthic community and the impact of spatial and temporal fluctuations in temperature on benthic cover on …

Taking The Metabolic Pulse Of The World's Coral Reefs, Tyler Cyronak, Andreas J. Andersson, Chris Langdon, Rebecca Albright, Nicholas R. Bates, Ken Caldeira, Renee Carlton, Jorge E. Corredor, Rob B. Dunbar, Ian Enochs, Jonathan Erez, Bradley D. Eyre, Jean-Pierre Gattuso, Dwight Gledhill, Hajime Kayanne, David I. Kline, David A. Koweek, Coulson Lantz, Boaz Lazar, Derek Manzello, Ashly Mcmahon, Melissa Melendez, Heather N. Page, Isaac R. Santos, Kai G. Schulz, Emily Shaw, Jacob Silverman, Atsushi Suzuki, Lida Teneva, Atsushi Watanabe, Shoji Yamamoto

Marine & Environmental Sciences Faculty Articles

Worldwide, coral reef ecosystems are experiencing increasing pressure from a variety of anthropogenic perturbations including ocean warming and acidification, increased sedimentation, eutrophication, and overfishing, which could shift reefs to a condition of net calcium carbonate (CaCO3) dissolution and erosion. Herein, we determine the net calcification potential and the relative balance of net organic carbon metabolism (net community production; NCP) and net inorganic carbon metabolism (net community calcification; NCC) within 23 coral reef locations across the globe. In light of these results, we consider the suitability of using these two metrics developed from total alkalinity (TA) and dissolved inorganic carbon (DIC) …

Thirty Years Of Research On Crown-Of-Thorns Starfish (1986–2016): Scientific Advances And Emerging Opportunities, Morgan S. Pratchett, Clemon F. Caballes, Jennifer C. Wilmes, Samuel Matthews, Camille Mellin, Hugh P. A. Sweatman, Lauren E. Nadler, Jon Brodie, Cassandra A. Thompson, Jessica Hoey, Arthur R. Bos, Maria Byrne, Vanessa Messmer, Sofia A. V. Fortunato, Carla C. M. Chen, Alexandra C. E. Buck, Russell C. Babcock, Sven Uthicke

Marine & Environmental Sciences Faculty Articles

Research on the coral-eating crown-of-thorns starfish (CoTS) has waxed and waned over the last few decades, mostly in response to population outbreaks at specific locations. This review considers advances in our understanding of the biology and ecology of CoTS based on the resurgence of research interest, which culminated in this current special issue on the Biology, Ecology and Management of Crown-of-Thorns Starfish. More specifically, this review considers progress in addressing 41 specific research questions posed in a seminal review by P. Moran 30 years ago, as well as exploring new directions for CoTS research. Despite the plethora of research on …

Low Florida Coral Calcification Rates In The Plio-Pleistocene, Thomas C. Brachert, Markus Reuter, Stefan Kruger, James S. Klaus, Kevin P. Helmle, Janice M. Lough

Marine & Environmental Sciences Faculty Articles

In geological outcrops and drill cores from reef frameworks, the skeletons of scleractinian corals are usually leached and more or less completely transformed into sparry calcite because the highly porous skeletons formed of metastable aragonite (CaCO3) undergo rapid diagenetic alteration. Upon alteration, ghost structures of the distinct annual growth bands often allow for reconstructions of annual extension ( =  growth) rates, but information on skeletal density needed for reconstructions of calcification rates is invariably lost. This report presents the bulk density, extension rates and calcification rates of fossil reef corals which underwent minor diagenetic alteration only. The corals derive from …

Genomic Variation Among Populations Of Threatened Coral: Acropora Cervicornis, C. Drury, K. E. Dale, J. M. Panlilio, S. V. Miller, D. Lirman, E. A. Larson, E. Bartels, D. L. Crawford, M. F. Oleksiak

Marine & Environmental Sciences Faculty Articles

Background: Acropora cervicornis, a threatened, keystone reef-building coral has undergone severe declines (>90 %) throughout the Caribbean. These declines could reduce genetic variation and thus hamper the species’ ability to adapt. Active restoration strategies are a common conservation approach to mitigate species' declines and require genetic data on surviving populations to efficiently respond to declines while maintaining the genetic diversity needed to adapt to changing conditions. To evaluate active restoration strategies for the staghorn coral, the genetic diversity of A. cervicornis within and among populations was assessed in 77 individuals collected from 68 locations along the Florida Reef …

Sex On The Reef: Observations Of Coral Spawning In Dry Tortugas National Park, Karen L. Neely, Tracy A. Ziegler

Marine & Environmental Sciences Faculty Articles

In Florida’s remote Dry Tortugas National Park, coral reefs are an important management priority. Reproduction of coral species is difficult to monitor, however, and the reproductive potential of coral colonies at the park has been a matter of concern for several years. Two threatened species, elkhorn coral (Acropora palmata) and pillar coral (Dendrogyra cylindrus), were targeted for observation during their predicted annual spawning event in August 2014. Over a three-night period, both species were observed releasing gametes in near synchrony with observations at other sites in the Florida Keys. That these organisms are capable of being …

Leucothoe Eltoni Sp. N., A New Species Of Commensal Leucothoid Amphipod From Coral Reefs In Raja Ampat, Indonesia (Crustacea, Amphipoda), James Darwin Thomas

Marine & Environmental Sciences Faculty Articles

A new species of leucothoid amphipod, Leucothoe eltoni sp. n., is described from coral reefs in Raja Ampat, Indonesia where it inhabits the branchial chambers of solitary tunicates. With an inflated first gnathopod superficially resembling the genus Paraleucothoe, this new species has a two-articulate maxilla 1 palp characteristic of the genus Leucothoe. While described from coral reef environments in tropical Indonesia and the Philippines, it is an established invasive species in the Hawaiian Islands. The most likely mode of introduction was a US Navy dry dock transported to Pearl Harbor in 1992 from Subic Bay, Philippines.

Comment On “Chemically Mediated Behavior Of Recruiting Corals And Fishes: A Tipping Point That May Limit Reef Recovery”, Andrew H. Baird, Vivian R. Cumbo, Joana Figueiredo, Saki Harii, Tom Hata, Joshua S. Madin

Marine & Environmental Sciences Faculty Articles

Dixson et al. (2014) report that coral larvae navigate towards chemical cues associated with healthy reefs and avoid cues from degraded reefs. However, the swimming capabilities of coral larvae and well-established patterns of recruitment and reef hydrodynamics indicate that coral larvae will not be able to use these cues to recruit to healthy reefs. Perfuming degraded reefs, as suggested by Dixson et al (2014), will not enhance recovery rather it will distract from the difficult task of reducing fishing effort and improving water quality.

Enhanced Acidification Of Global Coral Reefs Driven By Regional Biogeochemical Feedbacks, Tyler Cyronak, Kai G. Schulz, Isaac R. Santos, Bradley D. Eyre

Marine & Environmental Sciences Faculty Articles

Physical uptake of anthropogenic CO₂ is the dominant driver of ocean acidification (OA) in the open ocean. Due to expected decreases in calcification and increased dissolution of CaCO₃ framework, coral reefs are thought to be highly susceptible to OA. However, biogeochemical processes can influence the pCO₂ and pH of coastal ecosystems on diel and seasonal time scales, potentially modifying the long‐term effects of increasing atmospheric CO₂. By compiling data from the literature and removing the effects of short‐term variability, we show that the average pCO₂ of coral reefs throughout the globe has increased ~3.5‐fold …

Environmental Variability And Biodiversity Of Megabenthos On The Hebrides Terrace Seamount (Northeast Atlantic), Lea-Anne Henry, Johanne Vad, Helen S. Findlay, Javier Murillo, Rosanna Milligan, J. Murray Roberts

Marine & Environmental Sciences Faculty Articles

We present the first remotely operated vehicle investigation of megabenthic communities (1004–1695 m water depth) on the Hebrides Terrace Seamount (Northeast Atlantic). Conductivity-temperature-depth casts showed rapid light attenuation below the summit and an oceanographic regime on the flanks consistent with an internal tide, and high short-term variability in water temperature, salinity, light attenuation, aragonite and oxygen down to 1500 m deep. Minor changes in species composition (3–14%) were explained by changes in depth, substratum and oceanographic stability, whereas environmental variability explained substantially more variation in species richness (40–56%). Two peaks in species richness occurred, the first at 1300–1400 m where …

Editorial Overview: Environmental Change Issues: Coral Reefs Sustainability And Its Challenges, Bernhard Riegl, Georgios Tsounis

Marine & Environmental Sciences Faculty Articles

No abstract provided.

Determining The Extent And Characterizing Coral Reef Habitats Of The Northern Latitudes Of The Florida Reef Tract (Martin County), Brian K. Walker, David S. Gilliam

Marine & Environmental Sciences Faculty Articles

Climate change has recently been implicated in poleward shifts of many tropical species including corals; thus attention focused on higher-latitude coral communities is warranted to investigate possible range expansions and ecosystem shifts due to global warming. As the northern extension of the Florida Reef Tract (FRT), the third-largest barrier reef ecosystem in the world, southeast Florida (25–27° N latitude) is a prime region to study such effects. Most of the shallow-water FRT benthic habitats have been mapped, however minimal data and limited knowledge exist about the coral reef communities of its northernmost reaches off Martin County. First benthic habitat mapping …

Tracking Transmission Of Apicomplexan Symbionts In Diverse Caribbean Corals, Nathan L. Kirk, Raphael Ritson-Williams, Mary Alice Coffroth, Margaret W. Miller, Nicole D. Fogarty, Scott R. Santos

Marine & Environmental Sciences Faculty Articles

Symbionts in each generation are transmitted to new host individuals either vertically (parent to offspring), horizontally (from exogenous sources), or a combination of both. Scleractinian corals make an excellent study system for understanding patterns of symbiont transmission since they harbor diverse symbionts and possess distinct reproductive modes of either internal brooding or external broadcast spawning that generally correlate with vertical or horizontal transmission, respectively. Here, we focused on the under-recognized, but apparently widespread, coral-associated apicomplexans (Protista: Alveolata) to determine if symbiont transmission depends on host reproductive mode. Specifically, a PCR-based assay was utilized towards identifying whether planula larvae and reproductive …

Modulation Of Light-Enhancement To Symbiotic Algae By Light-Scattering In Corals And Evolutionary Trends In Bleaching, Luisa A. Marcelino, Mark W. Westneat, Valentina P. Stoyneva, Jillian Henss, Jeremy Rogers, Andrew J. Radosevich, Vladimir Turzhitsky, Margaret Siple, Andrew Fang, Timothy D. Swain, Jennifer Fung, Vadim Backman

Marine & Environmental Sciences Faculty Articles

Calcium carbonate skeletons of scleractinian corals amplify light availability to their algal symbionts by diffuse scattering, optimizing photosynthetic energy acquisition. However, the mechanism of scattering and its role in coral evolution and dissolution of algal symbioses during “bleaching” events are largely unknown. Here we show that differences in skeletal fractal architecture at nano/micro-lengthscales within 96 coral taxa result in an 8-fold variation in light-scattering and considerably alter the algal light environment. We identified a continuum of properties that fall between two extremes: (1) corals with low skeletal fractality that are efficient at transporting and redistributing light throughout the colony with …

Synthesizing Larval Competence Dynamics And Reef-Scale Retention Reveals A High Potential For Self-Recruitment In Corals, Joana Figueiredo, Andrew H. Baird, Sean R. Connolly

Marine & Environmental Sciences Faculty Articles

Many organisms have a complex life-cycle in which dispersal occurs at the propagule stage. For marine environments, there is growing evidence that high levels of recruitment back to the natal population (self-recruitment) are common in many marine organisms. For fish, swimming behavior is frequently invoked as a key mechanism allowing high self-recruitment. For organisms with weak-swimming larvae, such as many marine invertebrates, the mechanisms behind self-recruitment are less clear. Here, we assessed whether the combination of passive retention of larvae due to re-circulation processes near reefs, and the dynamics of settlement competence, can produce the high levels of self-recruitment previously …

Depth-Variable Settlement Patterns And Predation Influence On Newly Settled Reef Fishes (Haemulon Spp., Haemulidae), Lance K. B. Jordan, Kenyon C. Lindeman, Richard E. Spieler

Marine & Environmental Sciences Faculty Articles

During early demersal ontogeny, many marine fishes display complex habitat-use patterns. Grunts of the speciose genus Haemulon are among the most abundant fishes on western North Atlantic coral reefs, with most species settling to shallow habitats (≤12 m). To gain understanding into cross-shelf distributional patterns exhibited by newly settled stages of grunts (<2 cm total length), we examined: 1) depth-specific distributions of congeners at settlement among sites at 8 m, 12 m, and 21 m, and 2) depth-variable predation pressure on newly settled individuals (species pooled). Of the six species identified from collections of newly settled specimens (n = 2125), Haemulon aurolineatum (tomtate), H. flavolineatum(French grunt), and H. striatum (striped grunt) comprised 98% of the total abundance; with the first two species present at all sites. Prevalence of H. aurolineatum and H. flavolineatumdecreased substantially from the 8-m site to the two deeper sites. In contrast, …

Human Impact On Atolls Leads To Coral Loss And Community Homogenisation: A Modeling Study, Bernhard Riegl, Charles R. C. Sheppard, Samuel J. Purkis

Marine & Environmental Sciences Faculty Articles

We explore impacts on pristine atolls subjected to anthropogenic near-field (human habitation) and far-field (climate and environmental change) pressure. Using literature data of human impacts on reefs, we parameterize forecast models to evaluate trajectories in coral cover under impact scenarios that primarily act via recruitment and increased mortality of larger corals. From surveys across the Chagos, we investigate the regeneration dynamics of coral populations distant from human habitation after natural disturbances. Using a size-based mathematical model based on a time-series of coral community and population data from 1999–2006, we provide hind- and forecast data for coral population dynamics within lagoons …

Spatial Analyses Of Benthic Habitats To Define Coral Reef Ecosystem Regions And Potential Biogeographic Boundaries Along A Latitudinal Gradient, Brian K. Walker

Marine & Environmental Sciences Faculty Articles

Marine organism diversity typically attenuates latitudinally from tropical to colder climate regimes. Since the distribution of many marine species relates to certain habitats and depth regimes, mapping data provide valuable information in the absence of detailed ecological data that can be used to identify and spatially quantify smaller scale (10 s km) coral reef ecosystem regions and potential physical biogeographic barriers. This study focused on the southeast Florida coast due to a recognized, but understudied, tropical to subtropical biogeographic gradient. GIS spatial analyses were conducted on recent, accurate, shallow-water (0–30 m) benthic habitat maps to identify and quantify specific regions …

Present Limits To Heat-Adaptability In Corals And Population-Level Responses To Climate Extremes, Bernhard Riegl, Samuel J. Purkis, Ashraf S. Al-Cibahy, Mohammed A. Abdel-Moati, Ove Hoegh-Guldberg

Marine & Environmental Sciences Faculty Articles

Climate change scenarios suggest an increase in tropical ocean temperature by 1–3°C by 2099, potentially killing many coral reefs. But Arabian/Persian Gulf corals already exist in this future thermal environment predicted for most tropical reefs and survived severe bleaching in 2010, one of the hottest years on record. Exposure to 33–35°C was on average twice as long as in non-bleaching years. Gulf corals bleached after exposure to temperatures above 34°C for a total of 8 weeks of which 3 weeks were above 35°C. This is more heat than any other corals can survive, providing an insight into the present limits …

Severe 2010 Cold-Water Event Caused Unprecedented Mortality To Corals Of The Florida Reef Tract And Reversed Previous Survivorship Patterns, Diego Lirman, Stephanie Schopmeyer, Derek Manzello, Lewis J. Gramer, William F. Precht, Frank E. Muller-Karger, Kenneth Banks, Brian Barnes, Erich Bartels, Amanda Bourque, James Byrne, Scott Donahue, Janice Duquesnel, Louis Fisher, David S. Gilliam, James C. Hendee, Meaghan E. Johnson, Kerry Maxwell, Erin Mcdevitt, Jamie Monty, Digna Rueda, Rob Ruzicka, Sara Thanner

Marine & Environmental Sciences Faculty Articles

Background

Coral reefs are facing increasing pressure from natural and anthropogenic stressors that have already caused significant worldwide declines. In January 2010, coral reefs of Florida, United States, were impacted by an extreme cold-water anomaly that exposed corals to temperatures well below their reported thresholds (16°C), causing rapid coral mortality unprecedented in spatial extent and severity.

Methodology/Principal Findings

Reef surveys were conducted from Martin County to the Lower Florida Keys within weeks of the anomaly. The impacts recorded were catastrophic and exceeded those of any previous disturbances in the region. Coral mortality patterns were directly correlated to in-situ and satellite-derived …

A New Species Of Leucothoid Amphipod, Anamixis Bananarama, Sp. N., From Shallow Coral Reefs In French Polynesia (Crustacea, Amphipoda, Leucothoidae), James Darwin Thomas, Traudl Krapp-Shickel

Marine & Environmental Sciences Faculty Articles

Both leucomorph and anamorph developmental stages of Anamixis bananarama sp. n., are illustrated and described from shallow back reef environments of Moorea, French Polynesia. Distinguished by vestigial fi rst gnathopods that persist in post-transformational adult males, this is the second species in the genus to exhibit this unusual character. In other features such as coxae and second gnathopods A. bananarama sp. n. resembles other Pacific Plate endemics of Anamixis known from the region. Specific host association is not documented but suspected to be small calcareous asconoid sponges associated with coral rubble.