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A comparison of genetic connectivity in two deep sea corals to examine whether seamounts are isolated islands or stepping stones for dispersal

View Article: PubMed Central - PubMed

ABSTRACT

Ecological processes in the deep sea are poorly understood due to the logistical constraints of sampling thousands of metres below the ocean’s surface and remote from most land masses. Under such circumstances, genetic data provides unparalleled insight into biological and ecological relationships. We use microsatellite DNA to compare the population structure, reproductive mode and dispersal capacity in two deep sea corals from seamounts in the Southern Ocean. The solitary coral Desmophyllum dianthus has widespread dispersal consistent with its global distribution and resilience to disturbance. In contrast, for the matrix-forming colonial coral Solenosmilia variabilis asexual reproduction is important and the dispersal of sexually produced larvae is negligible, resulting in isolated populations. Interestingly, despite the recognised impacts of fishing on seamount communities, genetic diversity on fished and unfished seamounts was similar for both species, suggesting that evolutionary resilience remains despite reductions in biomass. Our results provide empirical evidence that a group of seamounts can function either as isolated islands or stepping stones for dispersal for different taxa. Furthermore different strategies will be required to protect the two sympatric corals and consequently the recently declared marine reserves in this region may function as a network for D. dianthus, but not for S. variabilis.

No MeSH data available.


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Map of four sampling regions (a) for the two deep sea coral species Desmophyllum dianthus and Solenosmilia variabilis in the Southern Ocean and details of individual seamounts (b) sampled within the Tasmanian Seamounts complex, noting five replicate sites were sampled on each of Mini Matt and Hill U seamounts. Maps were generated using Manifold GIS (V8.29) www.manifold.net based on the publically available Australia Bathymetry and Topography Grid, June 2009 obtained from Geoscience Australia (www.ga.gov.au).
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f1: Map of four sampling regions (a) for the two deep sea coral species Desmophyllum dianthus and Solenosmilia variabilis in the Southern Ocean and details of individual seamounts (b) sampled within the Tasmanian Seamounts complex, noting five replicate sites were sampled on each of Mini Matt and Hill U seamounts. Maps were generated using Manifold GIS (V8.29) www.manifold.net based on the publically available Australia Bathymetry and Topography Grid, June 2009 obtained from Geoscience Australia (www.ga.gov.au).

Mentions: Here we have sampled both species across the same spatial scales, from oceanic ridges to multiple sites on a single seamount (Fig. 1) in order to make direct comparisons of the scale of dispersal and better understand ecological and evolutionary processes in these deep seamount ecosystems. In addition, recognising the increasing exploitation of deep sea ecosystems, we were able to compare genetic diversity and structure between fished and unfished seamounts to determine if there was evidence that fishing activities had reduced resilience of seamount coral communities.


A comparison of genetic connectivity in two deep sea corals to examine whether seamounts are isolated islands or stepping stones for dispersal
Map of four sampling regions (a) for the two deep sea coral species Desmophyllum dianthus and Solenosmilia variabilis in the Southern Ocean and details of individual seamounts (b) sampled within the Tasmanian Seamounts complex, noting five replicate sites were sampled on each of Mini Matt and Hill U seamounts. Maps were generated using Manifold GIS (V8.29) www.manifold.net based on the publically available Australia Bathymetry and Topography Grid, June 2009 obtained from Geoscience Australia (www.ga.gov.au).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5385499&req=5

f1: Map of four sampling regions (a) for the two deep sea coral species Desmophyllum dianthus and Solenosmilia variabilis in the Southern Ocean and details of individual seamounts (b) sampled within the Tasmanian Seamounts complex, noting five replicate sites were sampled on each of Mini Matt and Hill U seamounts. Maps were generated using Manifold GIS (V8.29) www.manifold.net based on the publically available Australia Bathymetry and Topography Grid, June 2009 obtained from Geoscience Australia (www.ga.gov.au).
Mentions: Here we have sampled both species across the same spatial scales, from oceanic ridges to multiple sites on a single seamount (Fig. 1) in order to make direct comparisons of the scale of dispersal and better understand ecological and evolutionary processes in these deep seamount ecosystems. In addition, recognising the increasing exploitation of deep sea ecosystems, we were able to compare genetic diversity and structure between fished and unfished seamounts to determine if there was evidence that fishing activities had reduced resilience of seamount coral communities.

View Article: PubMed Central - PubMed

ABSTRACT

Ecological processes in the deep sea are poorly understood due to the logistical constraints of sampling thousands of metres below the ocean’s surface and remote from most land masses. Under such circumstances, genetic data provides unparalleled insight into biological and ecological relationships. We use microsatellite DNA to compare the population structure, reproductive mode and dispersal capacity in two deep sea corals from seamounts in the Southern Ocean. The solitary coral Desmophyllum dianthus has widespread dispersal consistent with its global distribution and resilience to disturbance. In contrast, for the matrix-forming colonial coral Solenosmilia variabilis asexual reproduction is important and the dispersal of sexually produced larvae is negligible, resulting in isolated populations. Interestingly, despite the recognised impacts of fishing on seamount communities, genetic diversity on fished and unfished seamounts was similar for both species, suggesting that evolutionary resilience remains despite reductions in biomass. Our results provide empirical evidence that a group of seamounts can function either as isolated islands or stepping stones for dispersal for different taxa. Furthermore different strategies will be required to protect the two sympatric corals and consequently the recently declared marine reserves in this region may function as a network for D. dianthus, but not for S. variabilis.

No MeSH data available.


Related in: MedlinePlus