11th ICRS Abstract book - Nova Southeastern University

8.226
Bacterial Growth On Coral Mucus
Gil SHARON* 1 , Eugene ROSENBERG 1
1 Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel
Aviv, Israel
Coral mucus-degrading bacteria were isolated by an enrichment culture procedure. The
isolates were able to grow as pure cultures on 10% sterilized mucus in seawater, yielding
108 CFU per ml. The isolates, mostly Vibrio strains, were classified by classical and
molecular methods. When the 10% sterilized mucus was supplemented with glucose and
then inoculated with the mucus-degrading bacteria there was a 2-fold increase in CFU per
ml, whereas supplementation with NH4NO3 or K2HPO4 did not increase cell yield. The
indigenous bacterial population of coral mucus increased from 103 to 108 CFU per ml
when incubated at 30°C for 11 h, changing from a heterogeneous community to a Vibriodominated
population. Factors which regulate the abundance and diversity of coral mucus
bacteria are presented.
8.227
Effect Of Temperature And Light Stress On Bacterial Communities in Aiptasia
Pulchella
Nick JACHOWSKI* 1 , Joel THURMOND 2 , Kim RITCHIE 2
1 Stanford University, Stanford, CA, 2 Mote Marine Laboratory, Sarasota, FL
Populations of hard corals worldwide are declining due to mortality caused by bleaching
and disease. In some cases, bacteria have been shown to be the cause of bleaching and
disease. Corals naturally have microbial communities in their surface mucus that help to
inhibit potentially malignant microbes from harming coral health. However, under
conditions of environmental stress such as increased temperature, the beneficial microbial
communities can break down, leading to an overgrowth of opportunistic, malignant
microbes. In this study, Aiptasia pulchella, a model system for cnidarian-symbiosis, was
subjected to different temperature and light regimes and the microbial communities were
examined by terminal restriction fragment length polymorphisms (TRFLP) analysis. The
six treatments used in the two-week-long experiment were: light (control), dark, coldshocked
and light, cold-shocked and dark, 3-(3,4-dichlorophenyl)-1,1-dimethylurea
(DCMU) and light, heated and light. The cold-shocked treatments showed the greatest
loss of zooxanthellae. The results of this study will further the understanding of the
dynamics between environmental conditions and microbial communities in cnidarian
symbioses.
Poster Mini-Symposium 8: Coral Microbial Interactions
8.228
Coral Mucus Production By acropora Cervicornis And Its Utilization By Heterotrophic
Bacteria
Ryota NAKAJIMA* 1 , Kassim ZALEHA 2 , Rahim AZMAN 3 , Ross OTHMAN 3 , Tatsuki
TODA 1
1 Soka University, Tokyo, Japan, 2 KUSTEM, Terengganu, Malaysia, 3 UKM, Selangor, Malaysia
In situ mucus production by hard coral of Acropora cervicornis was measured quantitatively
and the degradation of mucus by heterotrophic bacteria was investigated at Bidong Island,
Malaysia. Mucus release rates for A. cervicornis were varied from 0.03 to 0.25 mg C cm -2 day -1
with an average of 0.09±0.09 mg C cm -2 day -1 . We found approximately 70 % of the released
mucus consisted of dissolved component and the remaining 30 % was particulate matter.
Concentrations of inorganic nutrients in the mucus were relatively higher than that of the
surrounding seawater. Phosphate concentrations were more than 100-fold higher in the coral
mucus compared to the surrounding seawater. In the mucus degradation experiment, seawatermucus
mixtures were incubated and compared with control runs for 24 hours. The bacterial
densities in the control runs stilly increased from 3.4×10 5 cells ml -1 to 6.6×10 5 cells ml -1 in the
incubation period. On the other hand, the bacterial densities in the seawater-mucus mixtures
considerably increased from 7.1×10 5 cells ml -1 to 87.9×10 5 cells ml -1 . In the control runs, there
were no substantial changes in the concentrations of dissolved and particulate organic carbon in
the incubation media. However, concentrations of both dissolved and particulate organic carbon
in the mucus mixtures were fairly decreased, which suggests that the heterotrophic bacteria
consumed and degraded of organic matter in the coral mucus.
8.229
Carbonate And Silicate Reef Sands From The Northern Red Sea Provide Different Micro-
Habitats For Specific Bacterial Communities
Barbara PFITZNER* 1,2 , Sandra SCHÖTTNER 1,2 , Alban RAMETTE 2 , Antje BOETIUS 2 ,
Christian WILD 3
1 Coral Reef Ecology Working Group(CORE) GeoBio-Center & Department of Earth and
Environmental Science, Ludwig-Maximilians-University, Munich, Germany, Munich,
Germany, 2 Microbial Habitat Group, Max Planck Institute for Marine Microbiology, Bremen,
Germany, Bremen, Germany, 3 Coral Reef Ecology Working Group(CORE) GeoBio-Center &
Department of Earth and Environmental Science, Ludwig-Maximilians-University, Munich,
Germany, München, Germany
In coral reefs of the Northern Red Sea the seafloor can be covered by either biogenous
carbonate or terrigenous silicate sands. Often, both kinds of reef sands occur in direct vicinity
to each other, thereby experiencing identical environmental conditions. However, previous
research showed that natural organic matter is degraded much faster in carbonate compared to
silicate reef sands of similar grain size. One possible reason for this finding may be that reef
sands of different mineralogy may also host different microbial communities. This study
presents the first data from comparative investigations on microbial community structure in
carbonate and silicate sands associated with a shallow fringing reef off Aqaba, Jordan. Using
ARISA, a high-resolution molecular fingerprinting tool targeting differences in the 16S-ITS
region, bacterial diversity and specificity were analyzed in correlation to the sand mineralogy in
a seasonal and vertical resolution. The results revealed significant differences in bacterial
community structure between the two sand types at all investigated sediment depths, which
suggests specific sand-microbe associations due to variations in micro-habitat structure. This
finding is of particular importance concerning the microbial community composition in the
sediment surface, which is directly exposed to and influenced by the input of organic matter
from the overlying water column. It also became evident, that seasonal changes are reflected in
the bacterial community patterns of the two reef sands, emphasizing the high dynamics of reefsand
bacteria. Overall, it can be concluded that coral-reef sands of different mineralogy favor
very specific microbial colonization patterns, also over sediment depth and time, and therefore
represent unique habitats for associated microbes. Further work will include the identification
and quantification of sand-associated bacteria and the correlation of obtained diversity patterns
with environmental parameters and biogeochemical data.
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