Corallimorphs and shipwrecks

Invasion of the corallimorphs! Wonder if this is happening in our local reefs.

Work TM, Aeby GS, Maragos JE 2008 "Phase Shift from a Coral to a Corallimorph-Dominated Reef Associated with a Shipwreck on Palmyra Atoll" PLoS ONE 3(8): e2989 doi:10.1371/journal.pone.0002989

Ok.. this isn't the particular species of corallimorph in the paper but i love this.. so bubbly..

Giant cup mushroom coral (Amplexidiscus fenestrafer)

"Corallimorpharians have several life history traits which allow them to rapidly monopolize patches of shallow substrate in tropical habitats. They are competitively superior to some coral species and possess anatomic structures such as elongated marginal tentacles that allow them to kill competing scleractinian corals... Additionally, corallimorpharians have three different modes of clonal replication (fission, pedal laceration and budding) that allow comparatively rapid monopolization of space on the reef...

The subsequent extent of the area dominated by corallimorphs in this study was much greater than other studies where corallimorphs rapidly invaded damaged areas but to a much more localized extent. This may be due to some substance leaching from the ship such as dissolved iron. Iron makes up the major component of steel and other ferrous metals in mooring buoys and ships, and is known to be a limiting resource for many marine organisms. Iron is an essential trace element for algal growth and nitrogen fixation, and equatorial and south Pacific oceanic waters are extremely low in available iron...

The extensive R. howesii invasion and subsequent loss of coral reef habitat at Palmyra Atoll and the potential association of corallimorph invasions with metal objects should serve as a clarion call to managers dealing with large metal objects such as wrecks on reefs. This will be especially relevant at remote low reef islands and atolls such as Palmyra where dissolved iron concentrations may be extremely limiting. The major sources of iron for the oceans are from wind-blown terrestrially derived dust or in coastal regions, from rivers and terrestrial run-off. Islands closer to continental landmasses or reefs at high islands where iron may be available from chemical erosion of volcanic soils may be less vulnerable to impacts of iron enrichment associated with metal objects. If removal of the shipwreck is not possible, regular systematic monitoring of the benthos for invasive organisms, including cnidarians, should be done to verify the rate of spread to support management actions such as removal of the shipwreck."