skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Ramicrusta invasive alga causes mortality in Caribbean coral larvae
The settlement of coral larvae is an important process which contributes to the success and longevity of coral reefs. Coral larvae often recruit to benthic structures covered with crustose coralline algae (CCA) which produce cues that promote settlement and metamorphosis. The PeysonneliaceaeRamicrustaspp. are red-brown encrusting alga that have recently become abundant on shallow Caribbean reefs, replacing CCA habitat, overgrowing corals and potentially threatening coral recruitment. In order to assess the threat ofRamicrustato coral recruitment, we compared the survival and settlement ofPorites astreoidesandFavia fragumlarvae to 0.5 – 2 mg ml-1solutions ofRamicrustasp. or CCA as well as sterile seawater (control). In all cases larval mortality was extremely high in theRamicrustatreatments compared to the CCA and control treatments. We found 96% (± 8.9% standard deviation, SD) mortality ofP. astreoideslarvae when exposed to solutions ofRamicrustaand 0 - 4% (± 0 - 8.9% SD) mortality in the CCA treatments. We observed 100%F. fragumlarval mortality when exposed toRamicrustaand 5 – 10% (± 10 – 20% SD) mortality in the CCA treatments. Settlement or surface interaction of larvae in the CCA treatments was 40 - 68% (± 22 - 37% SD) forP. astreoidesand 65 - 75% (± 10 - 19% SD) forF. fragum. TwoP. astreoideslarva that survivedRamicrustaexposure did settle/surface interact, suggesting that some larvae may be tolerant toRamicrusta. These results suggest thatRamicrustais a lethal threat to Caribbean coral recruitment.  more » « less
Award ID(s):
2150401
PAR ID:
10583366
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Frontiers media
Date Published:
Journal Name:
Frontiers in Marine Science
Volume:
10
ISSN:
2296-7745
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; (, Royal Society Open Science)
    The_Royal_Society_Publishing (Ed.)
    Coral reefs, hubs of global biodiversity, are among the world’s most imperilled habitats. Healthy coral reefs are characterized by distinctive soundscapes; these environments are rich with sounds produced by fishes and marine invertebrates. Emerging evidence suggests these sounds can be used as orientation and settlement cues for larvae of reef animals. On degraded reefs, these cues may be reduced or absent, impeding the success of larval settlement, which is an essential process for the maintenance and replenishment of reef populations. Here, in a field-based study, we evaluated the effects of enriching the soundscape of a degraded coral reef to increase coral settlement rates.Porites astreoideslarvae were exposed to reef sounds using a custom solar-powered acoustic playback system.Porites astreoidessettled at significantly higher rates at the acoustically enriched sites, averaging 1.7 times (up to maximum of seven times) more settlement compared with control reef sites without acoustic enrichment. Settlement rates decreased with distance from the speaker but remained higher than control levels at least 30 m from the sound source. These results reveal that acoustic enrichment can facilitate coral larval settlement at reasonable distances, offering a promising new method for scientists, managers and restoration practitioners to rebuild coral reefs. 
    more » « less
  2. ; ; ; (, Ecology)
    Abstract The abundance of many Caribbean corals has declined over the past few decades, yet nowPorites astreoidesis more common on many shallow reefs than in the 1980s and shows evidence of local adaptation. We compare the small‐scale (1–8000 m) genetic structure of this brooding species and the broadcasting coralOrbicella annularison reefs (<14 m depth) in St. John, US Virgin Islands, to examine how larval dispersal and asexual propagation contribute to the retention of genotypes within reefs. Populations ofP. astreoideshave genetic structure across reefs separated by a few 100 m, increased relatedness within reefs, and parthenogenetic larval propagation confirmed by parent–offspring genotyping. Within reefs,P. astreoidescolonies <1 m apart are more related, independent of clonal reproduction, than corals at greater distances. In contrast,O. annularislacks across‐reef genetic structure, has low relatedness within and among reefs, and does not produce asexual larvae. Small‐scale genetic structure and high relatedness inP. astreoidesare evident even without considering asexual propagation, but asexual reproduction enhances these differences. Neither species shows the genetic signature of inbreeding or reduced genotypic diversity despite the high within‐site relatedness ofP. astreoides. Monitoring on these reefs from 1987 indicates thatPoriteshas increased in abundance whileOrbicellahas decreased in abundance. The success ofPoritesis due to greatly increased settlement and recruitment compared withOrbicella. Together these results indicate that high numbers of locally retained and successful genotypes might explain the relative success ofPoriteson shallow, present‐day reefs in the Caribbean. 
    more » « less
  3. ; ; ; ; ; ; ; ; ; ; et al (, Proceedings of the Royal Society B: Biological Sciences)
    Reef-building crustose coralline algae (CCA) are known to facilitate the settlement and metamorphosis of scleractinian coral larvae. In recent decades, CCA coverage has fallen globally and degrading environmental conditions continue to reduce coral survivorship, spurring new restoration interventions to rebuild coral reef health. In this study, naturally produced chemical compounds (metabolites) were collected from two pantropical CCA genera to isolate and classify those that induce coral settlement. In experiments using four ecologically important Caribbean coral species, we demonstrate the applicability of extracted, CCA-derived metabolites to improve larval settlement success in coral breeding and restoration efforts. Tissue-associated CCA metabolites induced settlement of one coral species,Orbicella faveolata, while metabolites exuded by CCA (exometabolites) induced settlement of three species:Acropora palmata,Colpophyllia natansandOrbicella faveolata. In a follow-up experiment, CCA exometabolites fractionated and preserved using two different extraction resins induced the same level of larval settlement as the unfractionated positive control exometabolites. The fractionated CCA exometabolite pools were characterized using liquid chromatography tandem mass spectrometry, yielding 145 distinct molecular subnetworks that were statistically defined as CCA-derived and could be classified into 10 broad chemical classes. Identifying these compounds can reveal their natural prevalence in coral reef habitats and facilitate the development of new applications to enhance larval settlement and the survival of coral juveniles. 
    more » « less
  4. ; ; ; ; ; ; ; (, Frontiers in Marine Science)
    As the devastating impacts of global climate change and local anthropogenic stressors on shallow-water coral reefs are expected to rise, mesophotic coral ecosystems have increasingly been regarded as potential lifeboats for coral survival, providing a source of propagules to replenish shallower reefs. Yet, there is still limited knowledge of the capacity for coral larvae to adjust to light intensities that change with depth. This study elucidates the mechanisms underlying plasticity during early life stages of the coral Porites astreoides that enable survival across broad depth gradients. We examined physiological and morphological variations in larvae from shallow (8–10 m) and mesophotic (45 m) reefs in Bermuda, and evaluated differences in survival, settlement patterns and size among recruits depending on light conditions using a reciprocal ex situ transplantation experiment. Larvae released from mesophotic adults were found to have significantly lower respiration rates and were significantly larger than those derived from shallow adults, indicating higher content of energetic resources and suggesting a greater dispersal potential for mesophotic larvae compared to their shallow counterparts. Additionally, larvae released from mesophotic adults experienced higher settlement success and larger initial spat size compared to larvae from shallow adults, demonstrating a potential connection between parental origin, offspring quality, and recruitment success. Although both shallow and mesophotic larvae exhibited the capacity to survive and settle under reciprocal light conditions, all larvae had higher survival under mesophotic light conditions regardless of parental origin, suggesting that conditions experienced under low light may enable longer larval life, further extending the dispersal period. These results indicate that larvae from mesophotic Porites astreoides colonies are likely capable of reseeding shallow reefs in Bermuda, thereby supporting the Deep Reef Refugia Hypothesis. 
    more » « less
  5. ; ; ; ; ; (, Global Change Biology)
    Abstract Coral reefs are increasingly exposed to elevated temperatures that can cause coral bleaching and high levels of mortality of corals and associated organisms. The temperature threshold for coral bleaching depends on the acclimation and adaptation of corals to the local maximum temperature regime. However, because of larval dispersal, coral populations can receive larvae from corals that are adapted to very different temperature regimes. We combine an offline particle tracking routine with output from a high‐resolution physical oceanographic model to investigate whether connectivity of coral larvae between reefs of different thermal regimes could alter the thermal stress threshold of corals. Our results suggest that larval transport between reefs of widely varying temperatures is likely in the Coral Triangle and that accounting for this connectivity may be important in bleaching predictions. This has important implications in conservation planning, because connectivity may allow some reefs to have an inherited heat tolerance that is higher or lower than predicted based on local conditions alone. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email