Survival dynamics of scleractinian coral larvae and implications for dispersal

The octocoral Heliopora coerulea has emerged as one of the most dominant reef-building corals in the Bolinao Reef Complex, northern Philippines. One of the possible mechanisms that may contribute to the success of H. coerulea over scleractinian corals is its ability to compete effectively for space on the reef by inhibiting the settlement of coral larvae in its immediate vicinity. To determine whether H. coerulea can indeed inhibit larval recruitment, settlement tiles were deployed inside H. coerulea aggregations or on hard substrate at a distance of about 2 to 3 meters away. After three months of deployment, only a single H. coerulea recruit was observed on tiles placed within aggregations whereas many different coral recruits were observed on tiles placed on substrate away from the blue coral. These results suggest that adult H. coerulea can inhibit the settlement of scleractinian larvae. This effect may be mediated by various mechanisms, such as the production of allelopathic compounds, deployment of mesenterial filaments, and sweeper tentacles. However, further studies are needed to determine the modes of competition that are used by the coral.

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Development of a Sublethal Test to Determine the Effects of Copper and Lead on Scleractinian Coral Larvae

Archives of Environmental Contamination and Toxicology ◽

10.1007/s00244-004-3080-7 ◽

2004 ◽

Vol 47 (1) ◽

Cited By ~ 36

Author(s):

A. J. Reichelt-Brushett ◽

P. L. Harrison

Keyword(s):

Scleractinian Coral ◽

Coral Larvae

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Mono- and multispecies biofilms from a crustose coralline alga induce settlement in the scleractinian coral Leptastrea purpurea

Coral Reefs ◽

10.1007/s00338-021-02062-5 ◽

2021 ◽

Vol 40 (2) ◽

pp. 381-394

Author(s):

Lars-Erik Petersen ◽

Mareen Moeller ◽

Dennis Versluis ◽

Samuel Nietzer ◽

Matthias Y. Kellermann ◽

...

Keyword(s):

Bacterial Community ◽

Scleractinian Coral ◽

Marine Invertebrate ◽

Crustose Coralline Alga ◽

Coralline Alga ◽

Coral Larvae ◽

True Nature ◽

Settlement Behavior ◽

Microbial Strains ◽

Multispecies Biofilms

AbstractMicroorganisms have been reported to induce settlement in various marine invertebrate larvae but their specificity of inductive capacities for the settlement of coral larvae remains poorly understood. In this study, we isolated 56 microbial strains from the crustose coralline alga (CCA) Hydrolithon reinboldii using five different media either with or without additional antibiotics and/or spiked CCA extract. We tested the isolates for their potential to induce settlement behavior in larvae of the brooding scleractinian coral Leptastrea purpurea. From these 56 CCA-associated microbial strains, we identified six bacterial classes and 18 families. The culturable bacterial community associated with H. reinboldii was dominated by Gammaproteobacteria, Actinobacteria, and Alphaproteobacteria while the Illumina MiSeq analysis showed that the culture-independent bacterial community was dominated by Gammaproteobacteria, Alphaproteobacteria, and Flavobacteria. Furthermore, we found no correlation between inductive settlement capacities and phylogenetic relationships. Instead, settlement behavior of L. purpurea larvae was induced by specific isolated species. Strains #1792 (Pseudovibrio denitrificans), #1678 (Acinetobacter pittii), #1633 (Pseudoalteromonas phenolica), #1772 (Marine bacterium LMG1), #1721 (Microbulbifer variabilis), and #1783 (Pseudoalteromonas rubra) induced settlement behavior in coral larvae at mostly high and significant levels (≥ 40%) but the remaining isolates strongly varied in their activity. Multispecies biofilms consisting of four strains (#1792, #1678, #1633, and #1721) were observed to synergistically increase settlement behavior levels (> 90%); however, the addition of #1772 to the multispecies biofilms negatively affected coral larvae and resulted in a total loss of inducing activity. The findings provide new insights into the role of bacteria in the settlement process of scleractinian corals and may help to identify the true nature of bacteria-derived morphogenic cues.

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