11th ICRS Abstract book - Nova Southeastern University

7-17
Spatial variation in aspergillosis and the mycoflora associated to Gorgonia ventalina
in Puerto Rico.
Anabella ZULUAGA-MONTERO* 1 , Carlos TOLEDO-HERNÁNDEZ 1 , Jose Antonio
RODRÍGUEZ 1 , Paul BAYMAN 1 , Alberto SABAT 1
1 Biology, University of Puerto Rico, San Juan, Puerto Rico
Most of the coral disease literature has focused on identifying potential pathogens or
environmental factors linked to disease. However, to better understand the etiology of
coral diseases it is also necessary to increase our knowledge of the basic ecology of
marine microorganisms. Many fungal species reported in marine organisms are common
in land, but very little is known about their distribution in marine ecosystems. The
objectives of this study were to determine the spatial variation in prevalence of
aspergillosis, and relate it to the mycoflora associated with healthy and diseased colonies.
We measured prevalence at three times during one year at six reefs sites. Colonies were
tagged, photographed and categorized as healthy or diseased. The mycoflora associated
to G. ventalina was identified by morphology and sequencing of the ITS region. We
found significant differences in aspergillosis prevalence among sites. We also found
significant spatial variation in the composition of the fungi community, and between
healthy and diseased sea fans. However, sites with high or low prevalence did not have a
distinctive mycoflora. Aspergillus flavus was an ubiquitous isolate at almost all sites, as
well as in diseased and healthy colonies. A. sydowii was not isolated from diseased
colonies. The main cause of colony death was detachment, followed by colonies that
were overgrown by fouling organisms, and least by aspergillosis. The significant spatial
variation in the fungi community suggests that local environmental factors are
influencing the fungal composition of sea fans. The fact that A. sydowii was not isolated
from diseased tissue from any reef site supports the argument that aspergillosis may be
caused by a polymicrobial consortium. The data also indicates that aspergillosis is not a
significant cause of mortality for sea fans in Puerto Rico.
7-18
Emerging Infectious Diseases Of Coral Reef Sponges: aplysina Red Band
Syndrome On Caribbean Reefs
Deborah J. GOCHFELD* 1,2 , Robert W. THACKER 3 , Julie B. OLSON 4
1 National Center for Natural Products Research, University of Mississippi, University,
MS, 2 Environmental Toxicology Research Program, University of Mississippi,
3
University, Department of Biology, University of Alabama at Birmingham,
Birmingham, AL, 4 Department of Biological Sciences, University of Alabama,
Tuscaloosa, AL
A substantial and increasing number of reports have documented dramatic changes and
continuing declines in the health of Caribbean coral reef communities over the past few
decades. Disease is often implicated as a major factor contributing to these declines. To
date, most disease reports have focused on scleractinian corals, whereas sponge diseases
have been less frequently documented. Here we describe Aplysina Red Band Syndrome
(ARBS), which affects Caribbean rope sponges. Visible signs of disease presence
include one or more rust-colored leading edges, with a trailing area of necrotic tissue,
such that the lesion forms a contiguous band around a portion or the entire sponge
branch. Microscopic examination of the leading edge of the disease margin indicates that
filamentous cyanobacteria are responsible for the coloration. Although the presence of
this distinctive coloration is used to characterize the diseased state, it is not yet known
whether this cyanobacterium is directly responsible for disease causation. Approximately
10% of the Aplysina cauliformis sponges on reefs near Lee Stocking Island, Bahamas,
are affected by ARBS, and the disease has also been observed on reefs at other Caribbean
sites. Transmission studies in the lab and field demonstrated that contact with an active
lesion's leading edge was sufficient to spread ARBS to a healthy sponge, suggesting that
the etiologic agent, currently undescribed, is contagious. Population studies indicate
clumping of diseased individuals on the reef, but the presence of affected individuals in
isolation suggests that waterborne transmission is also likely. Studies to elucidate the
etiologic agent of ARBS are ongoing. Sponges are an essential component of coral reef
communities and emerging sponge diseases have the potential to impact benthic diversity
and community structure on coral reefs.
Oral Mini-Symposium 7: Diseases on Coral Reefs
7-19
The Pathological Studies Of Skeletal Anomaly in The Coral porites Australiensis
Naoko YASUDA* 1 , Yoshikatsu NAKANO 2 , Hideyuki YAMASHIRO 3 , Michio HIDAKA 4
1 Department of Marine and Environmental Science, Graduate School of Engineering and
Science, University of the Ryukyus, Nishihara, Japan, 2 Sesoko Station, Tropical Biosphere
Research Center, University of the Ryukyus, Motobu, Japan, 3 Department of Bioresources
Engineering, Okinawa National College of Technology, Nago, Japan, 4 Department of
Chemistry, Biology and Marine Science, Faculity of Science, University of the Ryukyus,
Nishihara, Japan
The skeletal anomalies (SAs) of the scleractinian corals have been reported from reefs
throughout the world and have been commonly referred to as ‘tumors’. The SAs are
characterized by swelled and abnormal skeletal structures, reduced number of polyps, and fewer
zooxanthellae as compared with healthy parts. Causative agents of SAs have not been
identified. In this study, the pathological characteristics of the SAs developed on a colony of
Porites australiensis in the reef at Kayo, Okinawa, Japan were investigated. The polyp density
was reduced in the SA due to enlargement of both calices and the coenosteum. Corallites in the
SA region lost the skeletal architecture characteristic to Porites australiensis. The soft tissue in
the SA region contained fewer and smaller spermaries and thinner gastrodermis containing
lower density of zooxanthellae than the adjacent ordinary tissue. The gross production of SA
tissues was lower than that of ordinary tissues and it decreased to almost 0 in 9 days after
isolation. However, when SA fragments were brought into contact with ordinary fragments
from the same colony, they fused and both SA and ordinary regions grew. The growth rate of
ordinary regions was lower when they were fused with SA fragments than those fused with
ordinary fragments. The present results suggest that SAs may be maintained by energy supply
from the surrounding healthy tissue. The SAs of the coral may act as parasite for host corals and
eventually decrease the fitness of the host coral.
7-20
Is Increased Scarring Of Hard Corals From Disease Associated With Subsequent Declines
in Coral Cover On Reefs Of The Great Barrier Reef.
Ian MILLER* 1 , Andrew DOLMAN 1
1 Long Term Monitoring, Australian Institute of Marine Science, Townsville, Australia
Increased reports of disease induced hard coral mortality in recent years have highlighted the
emerging threat coral disease poses to reef ecosystems. To study the effects of coral disease on
the Great Barrier Reef (GBR) the Australian Institute of Marine Science monitored causes of
coral mortality on a suite of 48 reefs throughout the Great Barrier Reef (GBR) annually from
1999 to 2005 and on a further 48 reefs biannually from 2006. Sampling consisted of
categorising corals scars according to signs commonly associated with coral disease (white
syndromes and black-band disease), crown-of-thorns starfish (COTS), Drupella spp. feeding
activity and scars that could not be assigned directly to any of these categories. In 2005
sampling was extended to include signs of recently defined disease formerly classified as white
syndromes or band diseases (brown band disease, skeletal eroding band disease and
atramentous necrosis). Of those categories recorded only increases in COTS scars were
independently associated with subsequent declines in coral cover on survey reefs. Between
1999 and 2005 there was no clear evidence to suggest there were any disease outbreaks that had
a significant impact (above background levels) on live coral cover on survey reefs. This is
despite the fact that scaring due to disease constitutes a relatively high proportion of the scars
observed. This suggests that though disease plays an important role in GBR coral communities
it mainly contributes to “background” levels of coral mortality. The relative proportion of scars
recorded show that white syndrome and unknown scars make up the most common category of
scars observed. The high proportion of scars from unknown sources suggests that the causes of
many corals scars remain unexplained and highlights the difficulty classifying coral scars based
on visual signs.
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