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Structuring effects of chemicals from the sea fan Phyllogorgia dilatata on benthic communities

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ABSTRACT

Despite advances in understanding the ecological functions of secondary metabolites from marine organisms, there has been little focus on the influence of chemically-defended species at the community level. Several compounds have been isolated from the gorgonian octocoral Phyllogorgia dilatata, a conspicuous species that forms dense canopies on rocky reefs of northern Rio de Janeiro State, Brazil. Manipulative experiments were performed to study: (1) the effects of live colonies of P. dilatata (physical presence and chemistry) on recruitment of sympatric benthic organisms; (2) the allelopathic effects of its chemicals on competitors; and (3) chemotactic responses of the non-indigenous brittle star, Ophiothela mirabilis. Early establishment of benthic species was influenced on substrates around live P. dilatata colonies and some effects could be attributed to the gorgonian’s secondary metabolites.In addition, the gorgonian chemicals also exerted an allelopathic effect on the sympatric zoanthid Palythoa caribaeorum, and positive chemotaxis upon O. mirabilis. These results indicate multiple ecological roles of a chemically-defended gorgonian on settlement, sympatric competitors, and non-indigenous species.

No MeSH data available.


Percent cover of coralline crustose algae (CCA) over disks treated with crude extract (Phyllogorgia) and controls, within 75% similarity groups.
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fig-10: Percent cover of coralline crustose algae (CCA) over disks treated with crude extract (Phyllogorgia) and controls, within 75% similarity groups.

Mentions: Two distinct groups within 75% percent similarity were apparent in the non-metric multidimensional ordination (nMDS) plot (Fig. 9B). However, the communities settled on treatment and control disks (n = 6 replicates per treatment) barely differed (ANOSIM R = 0.231, p = 0.056). According to the analysis of species individual contributions (SIMPER), settled communities on control disks had an average similarity of 78.4%, with Obelia sp. contributing more than 33% to that similarity. Similarity of settled communities near P. dilatata extracts was over 81%, with the hydrozoan Obelia sp. also contributing 21.74% to this pattern. The main differences between control and treatment could be attributed to barnacles and crustose coralline algae (CCA) that together accounted for over 25% of the dissimilarity observed between groups. CCA, cyanobacteria and Balanus trigonus recruited more on extract-treated disks (Table 1, Fig. 10).


Structuring effects of chemicals from the sea fan Phyllogorgia dilatata on benthic communities
Percent cover of coralline crustose algae (CCA) over disks treated with crude extract (Phyllogorgia) and controls, within 75% similarity groups.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382925&req=5

fig-10: Percent cover of coralline crustose algae (CCA) over disks treated with crude extract (Phyllogorgia) and controls, within 75% similarity groups.
Mentions: Two distinct groups within 75% percent similarity were apparent in the non-metric multidimensional ordination (nMDS) plot (Fig. 9B). However, the communities settled on treatment and control disks (n = 6 replicates per treatment) barely differed (ANOSIM R = 0.231, p = 0.056). According to the analysis of species individual contributions (SIMPER), settled communities on control disks had an average similarity of 78.4%, with Obelia sp. contributing more than 33% to that similarity. Similarity of settled communities near P. dilatata extracts was over 81%, with the hydrozoan Obelia sp. also contributing 21.74% to this pattern. The main differences between control and treatment could be attributed to barnacles and crustose coralline algae (CCA) that together accounted for over 25% of the dissimilarity observed between groups. CCA, cyanobacteria and Balanus trigonus recruited more on extract-treated disks (Table 1, Fig. 10).

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Despite advances in understanding the ecological functions of secondary metabolites from marine organisms, there has been little focus on the influence of chemically-defended species at the community level. Several compounds have been isolated from the gorgonian octocoral Phyllogorgia dilatata, a conspicuous species that forms dense canopies on rocky reefs of northern Rio de Janeiro State, Brazil. Manipulative experiments were performed to study: (1) the effects of live colonies of P. dilatata (physical presence and chemistry) on recruitment of sympatric benthic organisms; (2) the allelopathic effects of its chemicals on competitors; and (3) chemotactic responses of the non-indigenous brittle star, Ophiothela mirabilis. Early establishment of benthic species was influenced on substrates around live P. dilatata colonies and some effects could be attributed to the gorgonian’s secondary metabolites.In addition, the gorgonian chemicals also exerted an allelopathic effect on the sympatric zoanthid Palythoa caribaeorum, and positive chemotaxis upon O. mirabilis. These results indicate multiple ecological roles of a chemically-defended gorgonian on settlement, sympatric competitors, and non-indigenous species.

No MeSH data available.