11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 4: Coral Reef Organisms as Recorders of Local and Global Environmental Change
4.79
Impacts Of Climate Change On Coral Reefs Of India
R. JEYABASKARAN* 1 , R. RAJKUMAR 2 , P.L. YENNAWAR 1
1 Zoological Survey of India, Marine Aquarium and Research Centre, Digha, India,
2 Zoological Survey of India, National Coral Reef Research Institute, Port Blair, India
In India, coral reefs occur in four major regions namely Andaman & Nicobar, Gulf of
Kachchh, Gulf of Mannar and Lakshadweep Islands were severely affected by climate
change impacts. However the impacts vary from place to place. The 26 December 2004
tsunami caused subsidence and elevation of landmass in Andaman and Nicobar Islands
had led to severe shoreline erosion. Corals in 796 km2 reef flat areas were affected due to
siltation and sedimentation caused by the erosion. The live coral coverage of reef flats
was 20% and has been degraded further. Gulf of Kachchh reefs are facing rapid
degradation due to the extreme temperature variations which is between 44.8„aC in
summer and in extreme winter it reached 7.8„aC. Prolonged exposure of corals due to 4-7
meters tidal variation caused mortality of corals. Sediments are deposited at the rate of
2.5 cm per year and it had led to the coral mortality of 148 km2 reef flats. One or two
colonies of corals were alive in the reef flats. Lakshadweep Islands consists of 132 km2
coastline which severely affected by the erosion. Coastal erosion led to high
sedimentation in 136 km2 reef flats areas and caused mortality of corals and phase shift.
Sediment deposition of 1.0 cm per year in Gulf of Mannar had led to the degradation of
corals in 65 km2 reef flats. Reduction in water depth due to the sedimentation caused rise
in sea surface temperature. Due to this corals were severely affected by the diseases and
tumors. The other impacts of clime change on Indian coral reefs are discussed in the
paper in detail.
4.80
On The Causes Of Density Banding in Skeletons Of Montastraea Corals
Juan P. CARRICART-GANIVET* 1 , Elizabeth DÁVALOS-DEHULLU 1 , Héctor
HERNÁNDEZ-ARANA 1
1 El Colegio de la Frontera Sur, Unidad Chetumal, Chetumal, Q. Roo, Mexico
To obtain a reliable climate reconstruction from coral skeletons it is first necessary to
understand the way these grow and incorporate information. Thickness of skeletal
elements (exothecal and endothecal dissepiments, costae, septa, and theca-wall) as well
as the spacing between exothecal and endothecal dissepiments of the four extant Atlantic
species of Montastraea (M. annularis, M. faveolata, M. franksi and M. cavernosa) were
measured through high and low density bands. Our results show that growth periodicity,
controlled by the effect of temperature, is expressed in changes in thickness of costae and
exothecal dissepiments in the four studied Montastraea species, with no changes in
endothecal elements and theca-wall thickness which, in turn, has implications for
research on inclusive records using these species. Spacing between both exothecal and
endothecal dissepiments resulted not significantly different between high and low density
bands, and it is quite probably that their rhythmical formation is linked to lunar cycles.
4.81
Reconstruction Of Environmental Conditions And Coral Nutrition Using Coral Cores
Cornelia RODER* 1 , Claudio RICHTER 1
1 Center for Tropical Marine Ecology, Bremen, Germany
Coastal development has drastically changed the face of NE Hainan’s coral reefs over the past
decades. The establishment of harbours and aquaculture ponds and increasing urbanization have
increased sediment, POM and nutrient loads, which together with overfishing have resulted in a
phase shift from coral to algal dominated reefs.
Coral cores (Porites lutea) from differently impacted reefs along the East coast of Hainan
allowed to reconstruct the history of pollution and to examine the impact of water quality on the
growth and nutrition of the corals, where differences in intracrystalline δ 13 C and δ 15 N values
allowed to identify fertilizer vs. sewage derived food sources. Increases in OM in the skeleton
along with decreased growth rates are interpreted as increased heterotrophy by the coral host to
supplement reduced photosynthetic activity with degrading water quality.
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