11th ICRS Abstract book - Nova Southeastern University

8-31
Coral Associated Protists: Additional Partners in The Holobiont
Esti KRAMARSKY-WINTER* 1 , Moshe HAREL 2 , Nachshon SIBONI 3 , Etan BEN
DOV 3 , Diana RASOULOUNIRIANA 3 , Ariel KUSHMARO 3 , Loya YOSSI 1
1 Dept. of Zoology, Tel Aviv University, Tel Aviv, Israel, 2 Dept. Plant and Environmental
Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel, 3 The Department of
Biotechnology Engineering and The National Institute for Biotechnology, Ben Gurion
University, Beer Sheva, Israel
Recent investigations on coral associated communities have revealed that microbial
communities covering coral surfaces play important roles in colony well-being. A large
number of “aggregate” like organisms were recently observed covering the surface of
large-polyp corals such as Fungiids and Faviids from a number of geographic locations.
These organisms are dispersed in a patchy distribution on the polyp surface, with the
highest density occurring in the area of the polyp mouth. They can not be removed from
the coral surface by antibiotics, or by bleaching the corals in the dark. To identify these
organisms, mucus visibly containing aggregates, was gently scraped or milked from the
surface of the solitary Red Sea coral Fungia granulosa and examined microscopically,
and molecularly (using 18S rRNA gene and 16S mitochondrial rRNA gene sequences).
Microscopic investigation revealed that the organisms are embedded in the mucus and in
the tissue layers of this coral. They are approximately 5-30 µm in diameter, made up of
unique coccoid bodies and contain a nucleus, mitochondria and golgi. Both
morphological and molecular data lead us to identify these organisms as stramenopile
protists. To further characterize these organisms, samples of aggregate containing mucus
were diluted and plated and grown on a variety of media. Some of the resulting colonies
of microorganism were similar in gross morphology to those from the coral surface. Pure
cultures were grown to follow life cycle attributes, and were identified morphologically
and molecularly as belonging to the family Thraustochytridae, a group of protists known
for their ability to produce poly-unsaturated fatty acids (PUFA). The presence of this
group of microorganisms on the surface of many large polyp coral species from different
geographic locations may indicate their importance in coral holobiont health.
8-32
Global Diversity And Distribution Of Coral Associated Archaea And The Possible
Role in Coral Nitrogen Cycle
Nachshon SIBONI* 1 , Eitan BEN-DOV 1 , Alex SIVAN 1 , Ove HOEGH-GULDBERG 2 ,
Ariel KUSHMARO 1
1 Biotechnology Engineering, Ben-Gurion University, Be'er-Sheva, Israel, 2 Centre for
Marine Studies, University of Queensland, Brisbane, Australia
Corals harbor diverse and abundant prokaryotic communities (bacteria, archaea and
protozoa) that may have co-evolved with them. To date, only little attention has been
given to studies on the diversity and roles of archea in the coral holobiont. This research
focuses on the diversity and distribution of 424 coral-associated Archaeal sequences
associated with the surface mucus of three coral genera: Acantastrea, Favia and Fungia
sp. from Red Sea, Israel and from Heron Island, Australia. Sequencing of 16S rRNA
gene revealed dominance of Crenarchaeota (80% in average) in most of the coral
associated sequences. In the Crenarchaeota, 87% were similar (≥97%) to Thermoprotei,
of this class 76% were similar (≥97%) to candidatus Nitrosopumilus maritimus
(DQ085097), an ammonium oxidizer. Most of the Euryarchaeota sequences (73%) were
related to marine group II and other clades were related to anaerobic methanotrophic
archaea (8%), anaerobic nitrate reducer archaea (16%) and marine group III (3%). Many
of the Crenarchaeota and Euryarchaeota corals-associated archaeal sequences from Heron
Island GBR Australia (61%) and Gulf of Eilat, Red Sea (71%) were closely (≥97%)
related to sequences derived from Virgin Islands corals, Caribbean. This suggests that
coral-associated Archaea play an important role in holobiont physiology presumably by
acting as a nutritional sink of excess ammonium trapped in the mucus layer, by
nitrification and denitrification process.
Oral Mini-Symposium 8: Coral Microbial Interactions
8-33
Occurrence Of Epidermal Bacteria in The Scleractinian Coral montastraea Cavernosa
D. Abigail RENEGAR* 1 , Genelle F. HARRISON 2 , Patricia L. BLACKWELDER 1,3 , Joel E.
THURMOND 2 , Kimberly B. RITCHIE 2 , Bernardo VARGAS-ANGEL 4
1 National Coral Reef Institute, Nova Southeastern University Oceanographic Center, Dania, FL,
2 Center for Coral Reef Research, Mote Marine Laboratory, Sarasota, FL, 3 RSMAS, University
of Miami, Miami, 4 Coral Reef Ecosystem Division, NOAA Pacific Islands Fisheries Science
Center, Honolulu, HI
Montastraea cavernosa is an important scleractinian reef-building coral, found
throughout South Florida and the Caribbean. Examination of numerous fieldcollected
and experimental specimens of this coral with transmission electron
microscopy (TEM) revealed the presence of bacteria exclusively in the epidermal
tissue. To identify these bacteria, DNA was isolated from coenosarc tissue followed by DGGE
analysis of the 16S-V3 rDNA genes. Cloning and 16S rRNA sequence analysis identified the
predominant bacteria as members of the Lactobacillus/Lactococcus bacterial groups. These
Gram-positive bacteria are commonly associated with sewage. Lactobacilli are anaerobic
bacteria, found in the human digestive tract and rotting plant matter that convert lactose and
sugars into lactic acid. Lactococcus are motile bacteria common in dairy. The occurrence of
bacteria within the epidermis of M. cavernosa raises the question of the role of bacteria within
coral tissue. It is unknown if these bacteria are normal endosymbionts or represent a pathologic
condition; in some corals the bacterial population appeared to completely overtake the tissue.
Additionally, individual amoebocytes were observed both in the epidermis and in mesoglea
adjacent to the epidermis. The amoebocyte cells in the epidermis were often actively engaged
in bacterial phagocytosis. The possibility that innocuous bacteria may become pathogenic
under stress highlights the importance of understanding and quantifying how environmental
stress may affect the nature of the coral/zooxanthellae/bacterial association. This study
represents ongoing research directed at the development of monitoring and predictive
indices based on TEM and fluorescence in-situ hybridization (FISH) assessment of
amoebocyte/bacteria ratios. FISH analyses are also being employed to aid in the identification
and localization of these bacteria in other species.
8-34
Bacterial Communities On Healthy And Diseased Corals: Associations With Rapid
Tissue Loss (White Plague)
Geoffrey M. COOK* 1 , Masoumeh SIKAROODI 1 , Patrick M. GILLEVET 1 , Paige
ROTHENBERGER 1 , Esther C. PETERS 1,2 , Robert B. JONAS 1
1 Environmental Science and Policy, George Mason University, Fairfax, VA, 2 Tetra Tech, Inc.,
Fairfax
Although diseases of hermatypic corals, some of proven or suspected bacterial origin, pose a
serious global threat to coral reefs, the composition of bacterial communities on healthy corals
and those exhibiting signs of disease remains poorly understood. This investigation compared
bacterial communities associated with multiple pairs of apparently healthy and diseased
Montastraea annularis (species complex) colonies from offshore reefs in The Bahamas, U.S.
Virgin Islands, Cayman Islands, Bermuda, the Florida Keys National Marine Sanctuary, and the
Flower Garden Banks National Marine Sanctuary. Bacterial communities from apparently
healthy colonies and nearby colonies exhibiting signs consistent with white plague type II
(WPL II) were evaluated using both molecular and culture-dependent methods. Length
heterogeneity PCR (LH-PCR) molecular fingerprints were used to interrogate the diversity and
relative abundance of both whole and culturable communities. Bacterial communities
associated with diseased corals, regardless of geographical location, were more similar to each
other than to communities from apparently healthy tissue on either diseased or healthy colonies.
A comparison of the whole-bacterial community molecular fingerprint, regardless of tissue
type, with the culturable community revealed far greater similarities than expected.
Comparison of amplicon lengths and relative abundances suggest that many of the bacterial taxa
in coral communities are culturable and that these represent the most abundant bacteria.
Dominant microbial taxa include the genera Vibrio and Pseudoalteromonas. Strains of
Pseudoalteromonas are known to produce toxins that lyse dinoflagellates and diatoms. These
data imply an association between complex bacterial communities and rapid tissue loss
diseases.
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