Insidious coral killer invading Palmyra Atoll reef

Date:
August 10, 2021
Source:
University of Hawaii at Manoa
Summary:
The reefs at Palmyra Atoll, a small outlying atoll in the equatorial
Pacific Ocean, have been undergoing a shift from stony corals
to systems dominated by corallimorphs, marine invertebrates that
share traits with both anemones and hard corals. Marine biology
researchers discovered that although the invading corallimorph is
the same species that has been there for decades, its appearance
recently changed, and it became much more insidious.



FULL STORY ==========================================================================
The reefs at Palmyra Atoll, a small outlying atoll in the equatorial
Pacific Ocean, have been undergoing a shift from stony corals to systems dominated by corallimorphs, marine invertebrates that share traits with
both anemones and hard corals. A published study in Coral Reefs led by University of Hawaii at Manoa marine biology researchers discovered
that although the invading corallimorph is the same species that has
been there for decades, its appearance recently changed, and it became
much more insidious.


========================================================================== Phase shifts such as this are being seen in many marine environments
globally - - whether due to local pollution, global climate change or
natural environmental variation. Researchers from UH Manoa's School of
Ocean and Earth Science and Technology (SOEST) wanted to determine if
a new species of corallimorph was responsible for the takeover in Palmyra.

"These phase shifts are negative to our overall biodiversity," said
Kaitlyn Jacobs, lead author of the study and graduate student at the
Hawai'i Institute of Marine Biology in SOEST. "In the last decade,
Palmyra's nearshore reefs have been invaded by corallimorph colonies that
can rapidly monopolize the seafloor and reach 100% cover in some areas." Outcompeting surrounding corals Jacobs and her team used DNA data
to compare the mitochondrial genomes of four corallimorph individuals
collected from Palmyra Atoll. They discovered that the corallimorph that
was outcompeting surrounding corals is not a new species but rather is
most closely related to a species from Okinawa, Japan.

The Palmyra Atoll National Wildlife Refuge was created in 2001 and has
been protected ever since. The atoll has been characterized as a nearly pristine coral reef ecosystem -- supporting a highly productive ecosystem
and high levels of coral cover.

Because of their adaptability, corallimorphs are excellent competitors. In addition to being able to kill corals directly, they can quickly move
into disturbed areas and out-compete surrounding organisms, creating a
sort of blanket on the reef.

"There is concern among scientists and conservationists that the phase
shift from stony coral-dominated habitats may be irreversible due to a
negative feedback loop of coral decline and subsequent algal, sponge or corallimorph domination," said Jacobs.

Biodiversity is extremely important for the health of any ecosystem --
each organism has a role.

"So if we can better understand these shifts at the genomic level it can
better help resource managers deal with large outbreaks effectively,"
said Jacobs.

========================================================================== Story Source: Materials provided by University_of_Hawaii_at_Manoa. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Kaitlyn P. Jacobs, Cynthia L. Hunter, Zac H. Forsman, Amanda
L. Pollock,
Mariana Rocha de Souza, Robert J. Toonen. A phylogenomic examination
of Palmyra Atoll's corallimorpharian invader. Coral Reefs, 2021;
DOI: 10.1007/s00338-021-02143-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210810143107.htm

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