11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 10: Ecological Processes on Today's Reef Ecosystems
10.367
Comparison Between Extension Rate And Coral Coverage Of Coral Lifeforms
Yumi FUCHINOUE* 1 , Tomoko OKASHITA 1 , Takeshi MAEKAWA 1 , Ryota
NAKAJIMA 1 , Rajuddin KUSHAIRI 2 , Ross OTHMAN 3 , Tatsuki TODA 1
1 Soka University, Tokyo, Japan, 2 Universiti Industri Selangor, Selangor Darul Ehsan,
Malaysia, 3 Universiti Kebangsaan Malaysia, Selangor D. E., Malaysia
Common field measurements of coral growth are extension rates which are not reliable
for quantitatively assessing reef growth due to the diversity of lifeform structures. The
purpose of this study was to measure the extension rate and coral coverage of various
coral lifeforms. The survey was carried out on fringing reefs at Tioman Island
(2°50′00″N; 104°10′00″E) in Malaysia. Observed corals were categorized into five
lifeforms: Acropora branching (ACB), Acrpora digitate (ACD), Acropora tablate (ACT),
Coral encrusting (CE), and Coral massive (CM). Coral extension rates (m year-1) and
coral coverage (m2 year-1) were measured from digital photographs by image analysis
software. The coral extension rate was measured by linear growth corals. The coral
coverage was calculated using the outline structure of the coral. ACD (77.1 ± 13.5 mm
year-1) and ACB (69.7 ± 23.3 mm year-1) showed the highest coral extension rates of all
five types. However, ACD and ACB showed significant differences in coral coverage.
Coral coverage of thick and close spacing ACD was 60% while thin and broad spacing
ACB showed coral coverage was 22%. Other lifeform structures showed similar coral
coverage to ACB. The results show that careful attention must be made to lifeforms
structures when measuring reef growth from extension rate. Further, the present study
confirmed that image analysis techniques are suitable for estimating the reef growth of
diverse structures of coral lifeforms.
10.368
Long Term Population Patterns Of coralliophila Abbreviata in Relation To Host
Coral acropora Palmata
Margaret MILLER 1 , Ashley CEDZO* 2,3
1 National Marine Fisheries Service, Southeast Fisheries Science Center, National
Oceanic and Atmospheric Administration, Miami, FL, 2 Department of Biology and
Marine Biology, University of North Carolina at Wilmington, Wilmington, NC, 3 National
Marine Fisheries Service (Ernest F. Hollings Scholar), National Oceanic and
Atmospheric Administration, Miami
Corals are declining in health and cover worldwide due to a wide range of influences.
Specifically, corals of the Acropora genus are rapidly dying off throughout the
Caribbean. In addition to the anthropogenic effects experienced on these reefs, there are
also natural processes affecting the corals. One such process is predation by
corallivorous snails. The purpose of this research was to determine long term population
patterns of the corallivorous snail, Coralliophila abbreviata, in relation to abundance and
condition of its host coral, Acropora palmata. Annual surveys are conducted at six study
sites in the upper Florida Keys, USA. In addition to the total number, size, and condition
of coral colonies, number and size of snails found on each colony is measured. Over nine
years (a period with substantial A.palmata mortality), three of the sites, as well as the
overall mean for the six sites, showed statistically significant correlations between coral
abundance and snail density. That is, as total live tissue cover at the site decreases, the
number of snails per total live area increases. This inverse correlation of coral
abundance with snail density indicates a positive feedback as snail predation appears to
exacerbate other sources of coral mortality. This positive feedback likely results from the
utilization of alternate host coral species by the snails.
10.369
Recruitment Of oulastrea Crispata On Artificial And Natural Subtrata in Tung Ping
Chau Marine Park, Hong Kong Sar, China
Wai Chun MA 1 , Put ANG, JR.* 1
1
Marine Science Laboratory, Department of Biology, The Chinese University of Hong Kong,
Shatin, N.T., Hong Kong
Coral recruitment is a rare and slow process in Hong Kong. The seasonal and annual variations
on the recruitment of Oulastrea crispata were monitored for a period of four and a half years
from 1998 to 2003 on the artificial experimental granite rocks and the natural sedimentary
boulders. Recruitment of this coral species was recorded every season on the experimental
granite rocks but its rates fluctuated seasonally, with the highest mean (± SD) rate recorded in
2000 winter (7.72 ± 1.25 recruits/m2), and the lowest in 2002 autumn (0.34 ± 0.30 recruits/m2).
The fluctuation in recruitment rate, however, was not statistically significantly different among
seasons. The annual rate of recruitment on the experimental granite rocks remained the same
over the four and a half years of sampling. In contrast, recruitment was not recorded every
season on the natural substrata. The mean seasonal recruitment rate also fluctuated highly with
the highest rate recorded in 2000 winter (4.67 ± 5.89 recruits/m2), and lowest in 2001 spring
and 2002 spring (0 recruits/m2). Recruitment rate of Oulastrea crispata was not affected by the
density of the existing coral colonies. The fluctuation in recruitment rate may be due to the
variation in coral larval availability.
10.370
Facultative Symbiosis Between Coral And Seagrass
Yoshikatsu NAKANO* 1 , Sayuko NINOMIYA 2 , Takahiko INOUE 2 , Yuka YANO 3 , Preetika
SINGH 3 , Makoto TSUCHIYA 3
1 Sesoko st., TBRC, University of the Ryukyus, Okinawa, Japan, 2 TOKYO KYUEI CO., Ltd.,
Saitama, Japan, 3 University of the Ryukyus, Okinawa, Japan
Corals and seagrasses often establish combined communities in the moat. This community
structure had been understood as the result of competition between them for substratum.
Recently, however, we found some evidences that let us interpret the relationship between
Thalassia hemprichii and the branching coral: Montipora digitata as facultative symbiosis in
the process of succession of their combined community. Seagrasses generally make habitat
segregation by the particle size of substratum. T. hemprichii prefers gravelly substratum.
Branching form corals supply a large amount of gravel in the moat. As the biomasses of both
organisms increased in the community, the erect stem-leaves of T. hemprichii grew bigger and
clustered being close each other in the gravelly substratum supplied as dead fragments of M.
digitata. Such a high density population of T. hemprichii is supported by highly porous
structure of substratum and a large amount of nutrient originated from suspended organic matter
filtered due to the complex structure of a meadow. Growth form of M. digitata changed to
slender in the dense meadow. This growth form easily causes fragmentation. The survival rate
of these fragments may increase in a stable meadow rather than on bare substratum. This
facultative symbiosis could be observed around large M. digitata population. Such a population
provides micro atoll-like topography in the shallow area of the moat. This area may be supplied
with gravelly substratum in its periphery, establishing the combined community like a
protection from current and wave erosion. T. hemprichii, a generalist, distributing wide range in
the moat may easily recruit on such gravelly substratum. A large-scale facultative symbiosis
may occur in shallow gravel areas under a special condition after the corruption of a large
branching coral community. This facultative symbiosis may dissolve at a certain point in the
process of succession.
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