Diverse and abundant coral associated microbial communities may play a key role in coral resistance to and recovery from unwavering stressors currently threatening coral reefs worldwide. The composition and structure of the coral microbiome is integral to
coral health as microbes can play beneficial (e.g. nutritional or protective) or negative
(e.g. pathogenic or opportunistic) roles in the coral. To review the impacts of stressors on the coral microbiome, I compiled data from 39 studies, each tracking microbial community shifts in corals experiencing stress from climate change, pollution or overfishing. Stress was associated with shifts in coral microbial communities. I found that regardless of stressor, microbial alpha diversity increased under stress, with Vibrionales,
Flavobacteriales and Rhodobacterales commonly found on stressed corals, and Oceanospirillales not as abundant on stressed corals. In addition, I used 16S rRNA sequencing to evaluate how local and global stressors affect the community structure of the coral microbiome for the two coral species, Porites lobata and Montipora foliosa. I
monitored tagged coral colonies at two human disturbance levels (i.e. high and low),
before and during a thermal bleaching hotspot at Kiritimati, Kiribati. Human disturbance,
a bleaching hotspot, and coral species were all important drivers of coral microbiome
community structure. My results suggest that human disturbance increases microbial
alpha and beta diversity, although results vary between coral species, with P. lobata
having more of a difference between disturbance levels. Similarly, bleaching increased
beta diversity at low disturbance sites. Both human disturbance and thermal stress
appeared to homogenize coral microbiomes between species and thermal stress appeared
to homogenize communities between disturbance levels. Thus, both human disturbance
and bleaching appear to stress the coral and destabilize its microbiome. However, intense
thermal stress (i.e. 12.86 DHWs) appears to have a greater influence than human
disturbance, probably due to corals responding to stressful conditions in a similar manner.
In conclusion, my results highlight the impact of local and global stressors on coral
microbiome community structure. / Graduate / 2018-04-26 / 0359
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/8059 |
| Date | 04 May 2017 |
| Creators | McDevitt-Irwin, Jamie |
| Contributors | Baum, Julia Kathleen |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | Available to the World Wide Web, http://creativecommons.org/licenses/by/2.5/ca/ |
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