11th ICRS Abstract book - Nova Southeastern University

24.1104
Biorock Corals – Backtracking The Notion Of Enhanced Growth And Prosperity
Esther M. BORELL* 1 , Sascha B.C. ROMATZKI 1 , Sebastian FERSE 1
1 Center for Tropical Marine Ecology (ZMT), Bremen, Germany
Seawater electrolysis has been promoted as a mechanism to enhance growth and health of
coral transplants growing on a cathode (biorock corals) but evidence supporting these
claims remains largely anecdotal. This study investigates the effect of seawater
hydrolysis on the maximum potential quantum yield (Fv/Fm), zooxanthellae densities,
chlorophyll content and growth rates of the congeneric species Acropora yongei and A.
pulchra.
Coral fragments of each species were transplanted to a depth of 5 m and grown on either
1) an iron cathode, 2) bamboo within the electric field, or 3) bamboo outside the electric
field. Fv/Fm of dark adapted A. yongei between 10:00-11:00 h after a treatment period of
4 months was significantly higher inside and outside the electric field than on the
cathode, which coincided with significantly higher zooxanthellae densities in corals
inside and outside the electric field compared to corals on the cathode. By contrast there
was no effect of treatment on Fv/Fm of A. pulchra but zooxanthellae densities were
significantly higher in corals on the cathode than inside and outside the electric field.
Chlorophyll a + c2 concentrations of both species were lowest inside the electric field.
Both species exhibited significantly higher growth rates within the electric field than on
the cathode or outside the electric field.
Since calcification is linked to zooxanthellae photosynthesis the low growth rates, low
Fv/Fm and concurrent low zooxanthellae densities of A. yongei grown on a cathode
indicate that electrochemical processes through seawater hydrolysis may adversely effect
important physiological processes in some coral species leading to reduced growth and
health. Although growth was electrically stimulated in both species, the results of this
study provide no support for the proposed physiological benefits of biorock corals over
corals transplanted onto other artificial substrates.
24.1105
Electrical Enhancement Of Coral Growth in Tobago
Lee Ann BEDDOE* 1 , John AGARD 1 , Dawn PHILLIP 1
1 Life Sciences, The University of the West Indies, St. Augustine, Trinidad and Tobago
It has been hypothesized that low direct current increases calcium carbonate deposition in
some corals, resulting in increased growth. The validity of this claim has been disputed
because of weaknesses in the experimental design of previous studies.
In this study, phase one developed and tested the experimental design while phases 2 and
3 were larger field experiments in Tobago. Electrically conductive racks, called
Buoyancy Test Racks (BRTs), small enough to carry individual coral fragments, served
as the cathode while a titanium coated iron mesh (Biorock ® ) was used as the anode.
Forty electrically charged coral nubbins were attached to the BRTs and the exact number
of nubbins with no electricity acted as control. The BRTs allowed the measurement of the
growth of individual nubbins via the Buoyant Weighing Technique.
Phase 2, using Porites porites and Acropora cervicornis, showed that growth was initially
negative in both the electrical treatments and controls during an apparent settling down
period of about 6 weeks, after which growth rates in the electrified treatment only started
to increase. Unacceptable mortality in the control resulted in the premature termination of
the experiment.
Results from the Paired T-test for phase 3 using Millepora sp. showed that in 4 weeks
there was a significant increase in air weight growth of 5.69g (P=0.0397) for treated
corals and a significant decrease in weight of -0.71g (P=0.0000) for control. Within 26
weeks the mean growth change for the treated corals was 20.44g (P=0.0000) and -1.05g
(P=0.0000) for the control.
Preliminary results indicate that the enhanced growth for one coral species (Millepora
sp.) supports the hypothesis. However, at least another six months is required in order to
make a more definitive conclusion. This technology has the potential to restore reefs that
are adversely affected by environmental change.
Poster Mini-Symposium 24: Reef Restoration
24.1106
The Influence Of Substrates On The Settlement, Survival, And Growth Rates Of Juvenile
Coral Of acropora Humilis
Siriwan USSAVAUSCHARIYAKUL* 1 , Suchana CHAVANICH 2 , Voranop VIYAKARN 2
1 Environmental Science (Interdisciplinary), Graduate school, Chulalongkorn University,
Bangkok, Thailand, 2 Department of Marine Science, Faculty of Science, Chulalongkorn
University, Bangkok, Thailand
Mineral accretion generated by electric current recently is used as a method for accelerating
coral growth and survival. This technique allows limestone to accumulate on substrates and
may help corals in reducing energy for coral calcification. In this study, we investigated
whether there were differences on growth and survival of coral, Acropora humilis, between
substrates that had mineral accretion and substrates that did not have. The experiments were
done in a hatchery. Three difference types of substrates were used (steel plate encrusted with
limestone, aluminum plate, and tile with coralline algae). In the experiments, the settlements of
larvae on differences substrates were conducted, and the survival and growth of juvenile corals
were monitored for 5 months. The results showed that the tile with coralline algae had the
highest number of settling larvae (63.2% ± 2.69) followed by steel plate encrusted with
limestone (23.5% ± 2.18), and aluminum plate (9.4% ± 3.33) respectively. In addition, there
were differences on the survival and growth rates of juvenile corals on difference types of
substrates. Unlike the settlement rate, high survival rates of juvenile corals occurred on the
aluminum plates (74.8% ± 6.4) compared to encrusted steel plate (66.1% ± 8.74), and tile with coralline
algae (31.1% ± 1.76). The results from the growth rates also showed that juvenile corals on
aluminum plate had the highest relative growth rate (31.6% /month), followed by encrusted steel
plate (24.7% /month), and tile with coralline algae (15% /month). When comparing between months,
juvenile corals on aluminum plate and encrusted steel plate had the highest relative growth rate
during the 4th and 5th month (34.2% and 24.8%, respectively) while corals on the tile with
coralline algae had the highest relative growth rate during the 2nd and 3rd month (33.3%).
24.1107
Artificial Reef Materials As Mitigation For Natural Reef Impacts: Comparison Of
Benthic And Fish Assemblages On Artificial And Adjacent Natural Reefs in Miami-Dade
County, Florida
Sara THANNER* 1 , Stephen BLAIR 1
1 Department of Environmental Resources Management, Miami-Dade County, Miami, FL
The Bal Harbour Artificial Reef was constructed in May of 1999 with 176 prefabricated
modules and 8,000 tons of limerock boulders as mitigation for natural reef impacts sustained
during a beach renourishment project. A long-term monitoring program was developed to
evaluate the effectiveness of these artificial reef materials as mitigation for natural reef impacts.
Benthic and fish assemblages on the modules, boulders, and two adjacent natural reefs were
monitored and compared. The natural reef areas showed stable fish and benthic populations
with consistent levels of similarity and abundance throughout the period of comparison. The
benthic assemblages on the artificial reef materials have shown significant changes over time,
with increasing density and diversity of benthic organisms, and increasing similarity to the
natural reef areas. The density and diversity of the benthic assemblages on the artificial reef
materials appear to be stabilizing. Fish assemblage comparisons, on the other hand, showed
distinct differences on the different artificial reef materials as well as between those of the
artificial and natural reefs. Differences in the physical characteristics between natural and
artificial reef materials (i.e., shape, relief, cryptic space, etc) have and will continue to affect the
extent to which the reefs can become similar.
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