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The Role of Variability in the Ecology and Evolution of Corals.

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Title:The Role of Variability in the Ecology and Evolution of Corals.
Authors:Ritson-Williams, Raphael D. W.
Contributors:Zoology (department)
Date Issued:Aug 2017
Publisher:University of Hawaiʻi at Mānoa
Abstract:Climate change is impacting multiple habitats and one of the most susceptible
ecosystems is coral reefs. There are some examples of corals that can acclimatize and
adapt to stress events. Measuring the variability in different processes will improve our
knowledge of the mechanisms of coral persistence.
The variability in competence time among larvae of different species of coral was
tested. There was extensive variation in settlement even in larvae from the same brood.
Coral larvae from multiple species had flexible settlement ecology, potentially
influencing connectivity among populations.
To better understand the impact of stress events on different coral phenotypes,
corals were monitored in Kāne‘ohe Bay on O‘ahu during two successive bleaching events
in 2014 and 2015. Different species showed variation in susceptibility to thermal stress.
One hundred and fifty individual colonies were tagged and visually monitored for their
bleaching status and recovery starting in October 2014. The tagged colonies had low rates
of total mortality with 19% of P. damicornis, 10% of M. capitata and no P. compressa
that died after 19 months of monitoring. There were different rates of recovery, with P.
compressa recovering more rapidly than M. capitata.
Individual P. compressa and M. capitata in Kāne‘ohe Bay were tagged as pairs,
one colony severely bleached adjacent to a healthy colony. Reduced representation
sequencing was conducted on 16 pairs of P. compressa to elucidate the role of genetics in
the bleaching susceptibility of these corals. One hundred and two genes were found that
segregated two clades of P. compressa in Kāne‘ohe Bay, but these clades did not
correspond to bleaching status or location. Of these one hundred and two genes, thirtyfour
were annotated of which three were from the mitochondrial genome and thirty-one
were from nuclear regions. The difference in these one hundred and two loci suggested
that there are two cryptic species of P. compressa. This research describes extensive
standing variability in the processes of coral recruitment, coral resistance to stress, and
coral genetic diversity. In marine ecology and evolution we need to understand the role of
variability to evaluate the persistence of corals into the future
Description:Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017.
Rights:All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: Ph.D. - Zoology

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