11th ICRS Abstract book - Nova Southeastern University

7-41
Linking Environmental Factors With Coral Disease Events in The Caribbean
Tyler R. L. CHRISTENSEN* 1 , Scott F. HERON 2 , William J. SKIRVING 2 , C. Mark
EAKIN 2 , Bette L. WILLIS 3 , C. Drew HARVELL 4 , Cathie A. PAGE 3 , Peter J. MUMBY 5 ,
Laurie J. H. RAYMUNDO 6 , Ernesto WEIL 7 , Eric JORDÁN DAHLGREN 8 , John F.
BRUNO 9 , Dwight K. GLEDHILL 1 , Alan E. STRONG 2 , Jessica A. MORGAN 1 , Gang
LIU 1
1 IMSG at NOAA Coral Reef Watch, Silver Spring, MD, 2 NOAA Coral Reef Watch,
Silver Spring, MD, 3 James Cook University, Townsville, Australia, 4 Cornell University,
Ithaca, NY, 5 University of Exeter, Exeter, United Kingdom, 6 University of Guam,
Mangilao, Guam, 7 University of Puerto Rico, Mayaguez, Puerto Rico, 8 Universidad
Nacional Autónoma de México, Puerto Morelos, Mexico, 9 University of North Carolina
at Chapel Hill, Chapel Hill, NC
Recent evidence indicates that some coral disease outbreaks are linked to occurrences of
elevated water temperature, compounding other risk factors such as high coral cover and
nutrient enrichment. NOAA’s Coral Reef Watch is investigating whether environmental
conditions conducive to outbreak events can be predicted using satellite sea-surface
temperature (SST) data. With other members of the Coral Reef Targeted Research
working groups for Coral Disease and Remote Sensing, we examined the relationship
between several novel thermal stress metrics and various disease-related impacts.
Previous studies have counted the number of warm SST anomaly occurrences and shown
links to disease events. Here we include both warm and cold SST anomalies, and the
accumulation of these values; recent extreme anomalies; and accumulations weighted by
duration of the anomaly. Increased understanding of the causal factors in coral disease
outbreaks will open the door for operational satellite monitoring of disease risk on coral
reefs globally.
7-42
Environmental Effects Of Sewage Disposal Practices in Bermuda
Ross JONES* 1
1 Bermuda Institute of Ocean Sciences (BIOS), St George's, Bermuda
Coral disease has played a significant role in shaping the present day coral reef
communities of Florida and the Caribbean, yet the pathology, etiology and epizootiology
of most coral diseases remain poorly understood. In particular, the link between
anthropogenic effects, decreased water quality and disease prevalence is not well known.
In the wider Caribbean region, domestic wastewater represents the largest point source
contributor (by volume) of land-based point sources of marine pollution. The disposal of
raw or improperly treated sewage can introduce suspended solids, excessive nutrients,
industrial chemicals, pharmaceutically active compounds, personal care products and
potential pathogens into the marine environment. In Bermuda, about 2.5 million litres of
untreated sewage (about 15% of the sewage generated daily) is disposed of at a single
outfall located on a sandy bottom 300 m away from the nearest reefs of the main terrace.
A Remotely Operated Vehicles (ROV) was used in addition to Acoustic Doppler Current
Profiler (ADCP) and drogue tracking studies to examine and characterize the flow
dynamics around the outfall, and select study reefs that are regularly inundated with
sewage. Video-surveys were used to quantify benthic cover and species compostion on
sewage-exposed and more remote (control) reefs, and reefs in different physiographic
reef zones (i.e. lagoonal patch reefs, outer rim reefs etc). Black Band Disease (BBD) and
White Plague Type II (WP) in the dominant reef building coral species was also
quantified at multiple locations across the platform including those close to, and distant
from, the sewage outfall. Overall, there is little or no evidence to suggest any
environmental effect on the reefs - in terms of changes in species composition and
abundance or coral disease prevalence - caused by the nearby release of millions of litres
per day of untreated sewage over the past decade.
Oral Mini-Symposium 7: Diseases on Coral Reefs
7-43
Effects of Fishing and Macroalgae on Coral Disease Dynamics
John BRUNO* 1 , Ivana VU 1 , Ernesto WEIL 2 , Hugh SWEATMAN 3
1 UNC Chapel Hill, Chapel Hill, NC, 2 University of Puerto Rico, La Parguera, Puerto Rico,
3 Australian Institute of Marine Science, Townsville, Australia
Outbreaks of infectious and non-infectious (e.g., bleaching) coral diseases are the primary cause
of recent coral losses around the world. There are several potential explanations for the widely
observed increase in the severity and frequency of coral epizootics. For example, there is
evidence that nutrient enrichment and anomalously high ocean temperature can increase within-
and among-colony disease spread rates. Another widely discussed explanation is that decades
of overfishing have disrupted the balance of coral reef ecosystems, making them more
susceptible to disease outbreaks and other disturbances. More specifically, the removal of
herbivores has led to increases in benthic macroalgae that could promote disease outbreaks
either by acting as pathogen reservoirs or vectors or by increasing the concentration of
Dissolved Organic Carbon. We performed a series of field manipulations in Puerto Rico to test
the hypothesis that fishing and macroalgae affect the severity of Caribbean yellow band disease
of Montastraea faveolata. The results from all three experiments indicate that macroalge has no
effect on yellow band disease prevalence or incidence. In a second case study, we performed a
longitudinal epidemiological analysis on the effects of macroalgae, fish density, and ocean
temperature on outbreaks of white syndrome across the Great Barrier Reef from 1996 through
2006. Even after accounting for the effect of coral cover, macroalgal cover was strongly
negatively related to white syndrome frequency. There was a clear threshold of macroalgal
cover of roughly 5%, above which outbreaks never occurred. Thus macroalgae or some factor
or process related to macroalgal cover (e.g., grazer density, identity or behavior), may protect
coral populations and communities from disease outbreaks. Our results indicate that
macroalgae are not the cause of coral disease outbreaks and coral losses and that coral
epizootics cannot be effectively controlled with local fisheries management designed to limit
algal biomass.
7-44
Temperature-dependent Induction of Virulence Factors in the Coral Pathogen Vibrio
coralliilyticus
Nikole E. KIMES* 1,2 , Lisa KILPATRICK 2,3 , Pamela J. MORRIS 1,2
1 Marine Biomedicine and Environmental Sciences, Medical University of South Carolina,
Charleston, SC, 2 Hollings Marine Laboratory, Charleston, SC, 3 National Institute of Standards
& Technology (NIST), Charleston, SC
Coral ecosystems have experienced unprecedented declines due in part to the increased
emergence and frequency of diseases throughout the Caribbean region. Increasing ocean
temperatures is one of the contributing factors thought to be driving this phenomenon. It is well
established that warmer temperatures can increase the abundance and virulence of some
pathogens, including water-born Vibrio spp. Vibrio coralliilyticus, is a temperature-dependent
coral pathogen first isolated from the Red Sea and the Indian Ocean. This Gram-negative
bacterium has been shown to infect the coral Pocillopora damicornis when temperatures reach
above 24.5°C, resulting in coral bleaching and lyses. While a previous study correlates
increased protease activity with V. coralliilyticus’ increased virulence when water temperatures
rise to 26°C or above, we hypothesize that a broader temperature-dependent induction of
multiple virulence factors is the mechanism underlying V. coralliilyticus’ virulence. This study
used two-dimensional liquid chromatography coupled with tandem mass spectrometry (2D-LC-
MS/MS) to identify proteins produced by V.coralliilyticus grown at 24°C and 27°C. We
identified 523 proteins expressed by V. coralliilyticus at 24°C and 839 proteins expressed at
27°C. Of those proteins, 504 were produced at both growth temperatures; whereas, 19 and 335
proteins were unique to the 24°C and 27°C growth conditions respectively. Additionally, we
identified 37 possible virulence factors unique to 27°C, while identifying only two unique
virulence factors at 24°C. Our results provide sufficient evidence to conclude that V.
coralliilyticus cultivated at the higher temperature (27°C) produces more proteins, including
known virulence factors, compared to cultivation at the lower temperature (24°C). Recent
climate change predictions calling for increases in ocean temperatures and research studies
indicating increased observations of infectious diseases in marine ecosystems enhance the
significance of this study.
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