Marine Microbial Communities in Health and Disease: an Exploration of Marine Bacterial Associations Across Space, Time, and Potential Roles Against Pathogens in the Context of the Current Global Climate Change Scenario

Among the most critically threatened ecosystems worldwide, coral reefs are currently facing an unprecedented decline. This is particularly evident throughout the Caribbean Sea, where the synergistic action of natural and anthropogenic stressors resulted in phase shifts in the composition of the benthic communities from being dominated by scleractinian corals to octocorals, sponges and/or macroalgae dominance. As Caribbean coral reefs have been indicated as a 'hot spot' for marine diseases, this dissertation primarily focused on providing insights into the putative roles of the microbial communities associated with sponges and octocorals in promoting the health of their host and acting as a defense against pathogens. These studies were conducted in different locations or under different abiotic conditions to provide more information on how changing environmental conditions can impact the functionality of host-microbial relationships. The sponge Aplysina cauliformis can be affected by Aplysina Red Band Syndrome and transmission experiments coupled with the analysis of the bacterial communities associated with both healthy and diseased individuals performed in this dissertation suggested that this disease is likely caused by a prokaryotic polymicrobial infection. As octocorals seem to be unaffected by the multitude of diseases threatening scleractinian corals, this dissertation also revealed that Caribbean octocorals host bacterial assemblages that appear to play an important role as a defense mechanism against pathogens through the production of secondary metabolites and direct competition at different temperatures. Similarly, antimicrobial compounds produced by the octocoral holobiont showed bioactivity against pathogens implicated in Stony Coral Tissue Loss Disease, highlighting the presence ofterpenoids in the most active fractions. Moreover, the exploration of the spatial and temporal stability of the bacterial associations within the Caribbean octocoral holobiont revealed species-specific dynamics and provided information regarding the co-occurrence of bacterial taxa that may play fundamental roles in structuring the octocoral-associated bacteriome.In summary, the results obtained in this dissertation enhanced our understanding of the associations and interactions between invertebrates that have become more prevalent on modern degraded reefs and their associated bacterial communities, while providing insights into the success of these organisms within the benthic communities of Caribbean reefs.

Grantor dc:publisher

University of Alabama Libraries

Year dc:date.issued

2023

Author dc:creator

• Monti, Matteo

Advisor dc:contributor.advisor

• Olson, Julie B

Contributors dc:contributor

• Mortazavi, Behzad
• Becker, Guilherme C
• Kocot, Kevin M
• Kemp, Dustin W

Statement dc:rights

• All rights reserved by the author unless otherwise indicated.

Language dc:language.iso

en_US, English

Dc Identifier Other

http://purl.lib.ua.edu/187897
u0015_0000001_0004719
Monti_alatus_0004D_15100

OAI identifier oai:identifier

oai:ir.ua.edu:123456789/10532