Unprecedented densities of Gorgonia sea fans on coral reefs in St. John, US Virgin Islands?

2020 ◽  
Author(s):  
Peter J Edmunds ◽  
Darren J Brown
Keyword(s):  
Coral Reefs ◽  
Virgin Islands ◽  
High Population ◽  
The South ◽  
Population Densities ◽  
Gorgonia Ventalina ◽  
Us Virgin Islands ◽  
South Shore

Gorgonia ventalina is an iconic member of the octocoral fauna of shallow Caribbean reefs, and here we report unprecedentedly high population densities on the south shore of St. John, 35 mo after being hit by two hurricanes.

scholarly journals Habitat and Client Diversity Influence the Skin Microbiome of the Caribbean Cleaner Goby Elacatinus Evelynae

2021 ◽  
Author(s):  
Ana Pereira ◽  
Marta C. Soares ◽  
Teresa Santos ◽  
Ana Poças ◽  
Marcos Pérez-Losada ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Virgin Islands ◽  
Physical Contact ◽  
Rrna Gene ◽  
Skin Microbiome ◽  
Us Virgin Islands ◽  
Alpha And Beta Diversity ◽  
Skin Bacteria ◽  
The Caribbean ◽  
Microbiota Diversity

Abstract Fish associated microorganisms are known to be affected by the environment and other external factors, such as microbial transfer between interacting partners. One of the most iconic mutualistic interactions on coral reefs are the cleaning interactions between cleanerfishes and their clients, during which direct physical contact occurs. Here, we characterized the skin bacteria of the Caribbean cleaner sharknose goby, Elacatinus evelynae, in four coral reefs of the US Virgin Islands using sequencing of the V4 region of the 16S rRNA gene. We specifically tested the relationship between gobies’ level of interaction with clients and skin microbiota diversity and composition. Our results showed differences in microbial alpha- and beta-diversity in the skin of gobies from different reef habitats and high inter-individual variation in microbiota diversity and structure. Overall, the results showed that fish-to-fish direct contact and specifically, access to a diverse clientele, influences the bacterial diversity and structure of cleaner gobies’ skin. Because of their frequent contact with clients, and therefore, high potential for microbial exchange, cleanerfish may serve as models in future studies aiming to understand the role of social microbial transfer in reef fish communities.

Three competitors in three dimensions: photogrammetry reveals rapid overgrowth of coral during multispecies competition with sponges and algae

2021 ◽  
Vol 657 ◽  
pp. 109-121
Author(s):  
LK Olinger ◽  
A Chaves-Fonnegra ◽  
IC Enochs ◽  
ME Brandt
Keyword(s):  
Coral Reefs ◽  
Surface Area ◽  
3D Models ◽  
Virgin Islands ◽  
Three Dimensions ◽  
Lobophora Variegata ◽  
Us Virgin Islands ◽  
Surface Area Change ◽  
Image Analyses ◽  
Multispecies Competition

Competition for limited space is an important driver of benthic community structure on coral reefs. Studies of coral-algae and coral-sponge interactions often show competitive dominance of algae and sponges over corals, but little is known about the outcomes when these groups compete in a multispecies context. Multispecies competition is increasingly common on Caribbean coral reefs as environmental degradation drives loss of reef-building corals and proliferation of alternative organisms such as algae and sponges. New methods are needed to understand multispecies competition, whose outcomes can differ widely from pairwise competition and range from coexistence to exclusion. In this study, we used 3D photogrammetry and image analyses to compare pairwise and multispecies competition on reefs in the US Virgin Islands. Sponges (Desmapsamma anchorata, Aplysina cauliformis) and macroalgae (Lobophora variegata) were attached to coral (Porites astreoides) and arranged to simulate multispecies (coral-sponge-algae) and pairwise (coral-sponge, coral-algae) competition. Photogrammetric 3D models were produced to measure surface area change of coral and sponges, and photographs were analyzed to measure sponge-coral, algae-coral, and algae-sponge overgrowth. Coral lost more surface area and was overgrown more rapidly by the sponge D. anchorata in multispecies treatments, when the sponge was also in contact with algae. Algae contact may confer a competitive advantage to the sponge D. anchorata, but not to A. cauliformis, underscoring the species-specificity of these interactions. This first application of photogrammetry to study competition showed meaningful losses of living coral that, combined with significant overgrowths by competitors detected from image analyses, exposed a novel outcome of multispecies competition.

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