11th ICRS Abstract book - Nova Southeastern University

8-22
Microbial Dynamics of Kiritimati Atoll
Tracey MCDOLE* 1 , Rob EDWARDS 2 , Liz DINSDALE 1 , Sheila WALSH 3 , Mary
DONOVAN 4 , Forest ROHWER 1
1 Cell and Molecular Biology, San Diego State University, San Diego, CA, 2 Math and
Computer Sciences, San Diego State University, San Diego, CA, 3 Scripps Institution of
Oceanography, UCSD, La Jolla, CA, 4 University of California, Santa Barbara, Santa
Barbara, CA
Potential anthropogenic stressors that contribute to coral reef decline include global
warming, eutrophication, and overfishing. It is becoming clear that microbes are
important factors in all of these scenarios. In 2005, the coral reef-associated microbial
community were surveyed in the northern line islands archipelago in the central pacific.
A ten fold increase in microbial numbers from kingman (human population = 0), to
kiritimati (population ~ 10,000) was observed. This increase in microbial abundance in
the water column was correlated with an increase in coral disease prevalence. Kiritimati
island itself also provides a gradient of human disturbance, without the latitudinal
gradient of the 2005 survey. In 2007, water column samples were collected from 10
meters using scuba from a total of 22 sites encircling the island. At each site, the
abundance of microbes and virus-like particles were enumerated using fluorescence
microscopy. Increasing microbial and viral density was directly correlated with
increasing human population. The maximum fold increase between sites for microbes and
virus-like particles was 20 and 40 fold respectively, with the highest numbers of bacteria
(5 x 106 cells/ml) and virus-like particles (2 x 107 cells/ml) occurring at the same site.
The number of bacteria colonies that grew on media selective for the known pathogens
staphylococcus spp and vibrio spp, as well as enteric bacteria also supported this trend.
The abundance of microbes and viruses will be correlated with numbers of fish,
prevalence of coral disease, number of coral recruits, and concentration of organic and
inorganic nutrients to help develop a model of coral reef microbial and macrobial
interactions.
8-23
Reef Community Structure Of Hawaiian Reefs: From The Microscopic To The
Macroscopic World
Florent ANGLY* 1 , Mark VERMEIJ 2 , Sheila WALSH 3 , Stuart SANDIN 4 , Meghan
DAILER 2 , Celia SMITH 5 , Forest ROHWER 1
1 San Diego State University, San Diego, CA, 2 University of Hawaii, Lahaina, HI,
3 University of California, San Diego, San Diego, CA, 4 Scripps Institution of
Oceanography, San Diego, CA, 5 University of Hawaii, Honolulu, HI
The acceleration of coastal urbanization in Hawaii this last decade has resulted in
increased nutrient runoff to the ocean and has led to a decrease in coral cover. Such coral
reef decline has important ecological as well as economical repercussions that need to be
prevented. Recent evidence suggests a role of microbes in the trajectory of decline of
coral reefs worldwide. The Line Islands archipelago in the central Pacific, including
atolls ranging from uninhabited to moderately inhabited, was previously surveyed and
microbially-driven food chains were reported for the most populated islands. We
hypothesize that microbial abundance and composition are also a fundamental to
understanding the trajectory of decline of Hawaiian coral reef ecosystems. To this end,
benthic cover, fish species composition and microbial and viral abundance were assessed
for 17 reefs of Maui and Lanai. Water parameters, including dissolved organic carbon
and nutrient levels, were also recorded. The data indicated that the reef ecosystems of
Maui were overall more degraded and algal-dominated than those of the nearby less
populated island of Lanai. Viruses and microbes (including the potentially human
pathogenic Vibrio bacterial genus) were more prevalent at degraded sites and their
abundance ranged from about the same to twice as many as compared to remote, central
Pacific atolls. The larger variation or patchiness in benthic composition of more degraded
reefs could be interpreted as a departure from a healthy stable state. Basic functional
relationships that are supposed to occur, like herbivorous fish control by fish predators,
were mostly lost. The current structure of Hawaiian coral reef ecosystems depicts an
intricate relation between the microscopic and the macroscopic world, that together with
the very complex history of these reefs largely drives today's observations.
Oral Mini-Symposium 8: Coral Microbial Interactions
8-24
Biogeography Of Reef Water And Coral-Associated Bacterial Communities Across The
Hawaiian Archipelago And Greater Pacific Basin
Jennifer L. SALERNO* 1,2 , Michael S. RAPPE 3
1 Zoology, University of Hawaii at Manoa, Honolulu, HI, 2 SOEST, Hawaii Institute of Marine
Biology, University of Hawaii at Manoa, Kaneohe, 3 SOEST, Hawaii Institute of Marine
Biology, University of Hawaii at Manoa, Kaneohe, HI
The bacterial community structure within coral and seawater samples collected from six islands
and atolls within the Hawaiian archipelago was investigated using a suite of molecular
biological and statistical techniques. Overall, we observed significant overlap in bacterial
communities associated with the reef-building coral, Porites lobata, from the majority of
islands and atolls within the Hawaiian archipelago and uncovered significant variation amongst
different colonies within an island or atoll. However, microbial communities associated with
Porites lobata colonies from French Frigate Shoals atoll were more similar to one another than
to any other colonies located within the archipelago. These communities also shared some
similarities with samples collected from Kaneohe Bay, Oahu, within the main Hawaiian Islands.
These observed differences have important management implications, as corals with different
assemblages of resident bacteria may respond differently to environmental changes. Seawater
samples from sites within the Hawaiian archipelago, Johnston Atoll, and American Samoa were
analyzed using similar techniques. Overall, seawater bacterial communities from the Hawaiian
Islands were more similar to one another than to the other locales examined. Seawater bacterial
communities from American Samoa were quite variable, but distinct from Hawaii, Johnston
Atoll shared similarities with both Hawaii and American Samoa, and samples from Kaneohe
Bay, Oahu grouped separately from all other locales. Overall, the biogeographic patterns of
bacterial communities physically associated with the coral Porites lobata differed from those
observed in planktonic bacterial communities, indicating that the underlying factors affecting
the dispersal and proliferation of bacteria associated with a benthic host versus those within the
plankton are different.
8-25
Microbial Profiling For Coral Restoration
Camille DANIELS* 1 , Mya BREITBART 1 , Ilze BERZINS 2 , Craig WATSON 3
1 University of South Florida, College of Marine Science, St. Petersburg, FL, 2 The Florida
Aquarium, Tampa, FL, 3 University of Florida, Tropical Aquaculture Laboratory, Ruskin, FL
Coral aquaculture and transplantation are currently being employed to address worldwide
decline of coral reefs and promote reef ecosystem recovery. Issues that arise with these
restoration strategies include possible introduction of diseases onto natural reefs and the
vulnerability of transplanted corals to bleaching and disease. While visual and histological
assessments are currently being used to determine if aquacultured coral fragments are suitable
for restoration, analyses of coral-associated microbes have yet to be incorporated as a health
indicator before transplantation. Before microbial community composition can be incorporated
into assessments of coral health, it is necessary to understand the spatial and temporal
variability of coral-microbe associations.
This project uses culture-based (TCBS plating and EcoPlate carbon utilization profiling) and
culture-independent (ARISA) methods to determine the composition and variability of the
microbial community associated with corals used for restoration. Spatial sampling on a large
Diploria clivosa parent colony revealed differences in microbial communities found in mucus
from different locations on the coral surface. Following fragmentation of this parent colony,
individual 2x2 cm fragments were sampled over time, allowing for increasing time intervals
between mucus sampling. Rapid changes in the coral-associated microbial community were
observed over time, with a significant increase in the number of culturable Vibrio sp. following
removal of the coral mucus. Subsequent experiments revealed that the corals (or their
associated microbes) adapt to reduce Vibrio numbers upon repeated sampling. The mechanism
of this adaptation is currently unknown, but will be a focus of future studies. Results from this
project will provide insight into the stability of coral-bacterial associations, and allow us to
develop a microbial baseline for coral species used for restoration in the Florida Keys.
Understanding microbe-coral interactions is critical for the future incorporation of microbial
community profiling into coral health assessments, which has direct implications for coral
restoration and conservation.
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