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Regulation Patterns in the Opening of Coral Polyps
Chloe Glynn, Jay Lunden, Erik Cordes
Department of Biology, Temple University Philadelphia
Abstract
Preliminary Results
Lophelia pertusa is a cold-water, reef-forming coral. The
colonies found in the deep benthos of the Gulf of Mexico
represent an important sea-floor ecosystem, as Lophelia
reefs create dimensionally complex habitats for a
number of diverse taxa. Until recently, in situ evaluation
of these community structures was limited by
accessibility. As part of understanding the behavioral
relationships present in coral communities, hourly
photographs of Lophelia “nubbins” in aquaria have been
since late August of 2011. Preliminary analysis of these
photographs suggests the coral polyps diurnally regulate
their patterns of opening.
Initial results indicate there is some regulated patterning to when
corals are active and visible. The polyps had a significant
observable response to feeding cycles and seem to exist on a
day/night cycle where the majority of activity is limited to the
evening and early morning hours.
Background
Over 1300 species have been discovered living on
Lophelia reefs, with up to 34% of species suspected to
be endemic.[1] This diversity is believed to result from the
complex, three-dimensional habitats created by its
branching skeleton, supporting a community structure
subject to unique interactions.[2] Although not currently
endangered, Lophelia is afforded a CITES II protection
status, indicating vulnerability to future extinction.
Methods
Subjects: 5-10 Lophelia “nubbins” collected using the
ROV Jason during the NOAA Lophelia II Expedition in
October of 2010. The corals were supported in PVC base
by HoldFast Expoxy, held in a 120 gallon aquarium at 89°C and constant light conditions.
Data Collection: Hourly photographs were collected onto
a Canon EOS 50D with a 17-85mm lens using the Canon
TC-80N3 intervalometer. Photos exhibiting discoloration
were AutoCorrected in Photoshop CS3, but otherwise
unaltered.
In total, 2100+ images were manually evaluated for the
number of visible polyps, the visible presence of
community associates (such as benthic snails, tube
worms, a squat lobster), and the direction and distance
moved by each motile organism between slides. The data
was assembled in an Excel spreadsheet and will be
subject to correlational analysis in MATLab.
Discussion
Although the polyps display time-sensitive patterns of opening
and closing, the colonies sampled exist well below the photic
zone in the Gulf of Mexico.
The residual, circadian schedule may indicate phylogenetic
history and relationship with tropical corals found in the photic
zone. Current testing indicates that several species of octocoral
now found in shallow waters originated and diversified in the
deep-sea before encroaching upon shallow ecosystems.[3]
Future Recommendations:

Establish several week in situ reef observation

Determine phylogenetic histories for more coral species

Expand noninvasive exploration to document endemic species

Limit off-shore drilling until further assessment can be made
References
[1]Roberts, J.M., Wheeler, A.J., Freiwald, A., 2006. Reefs of the Deep: The
Biology and Geology of Cold-Water Coral Ecosystems. Science. 312, 543-547.
[2] Roberts, J.M., 2005. Reef-aggregating behaviour by symbiotic eunicid
polychaetes from cold-water corals: do worms assemble reefs? J. Mar. Bio.
Ass. U.K.. 85, 813-819.
[3] Lindner A, Cairns SD, Cunningham CW (2008) From Offshore to Onshore:
Multiple Origins of Shallow-Water Corals from Deep-Sea Ancestors.
PLoS ONE 3(6): e2429. doi:10.1371/journal.pone.0002429
Acknowledgements
Dana Dawson, McNair Director
Kristy Cordero, STEM Graduate Extern
The McNair Scholars Program
Bureau of Ocean and Energy Management and NOAA Office of
Ocean Exploration