11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 25: Predicting Reef Futures in the Context of Climate Change
25.1157
Potential Impacts Of Anthropogenic Climate Change On Coral Reefs And
Mangroves In Madagascar
Katie ARKEMA* 1 , Jameal SAMHOURI 2
1 Ecology, Evolution and Marine Biology, University of California, Santa Barbara,
Seattle, WA, 2 Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA
Madagascar is best known for its terrestrial biodiversity and endemism. However, the
approximately 6,000 km of Malagasy coastline are also home to an impressive diversity
of marine habitats and species. Coral reefs and mangroves, which are expected to be
particularly vulnerable to anthropogenic climate change, occur along much of the
country’s coastline. World Wildlife Fund (WWF) and Conservation International (CI)
are assessing the vulnerability of coral reefs to increases in ocean temperature, sea level
rise, changes in water chemistry, and other potential impacts of climate change on
Malagasy marine ecosystems. One aspect of this assessment is a synthesis of peer
reviewed literature to determine current knowledge about the geographic distribution of
various habitats and identify research explicitly examining the impacts of climate change
on ocean ecosystems in Madagascar. We found very few papers with the objective to
explore potential impacts of climate change on Madagascar marine ecosystems; however,
the consensus view based on recent field surveys is that Madagascar’s coral communities
are healthy relative to other areas in the western Indian Ocean. Nevertheless, some areas
of Madagascar were heavily impacted by the 1998 El Nino associated bleaching event
and many corals could die if such intense bleaching events occur in the future.
Furthermore, the literature indicates that coral reefs and mangroves extend along >3,500
km of coastline, including the entire west coast and parts of the north and central east
coast. The southwestern coast of Madagascar is heavily populated and much of the
country’s rivers drain to the west, dumping sediments, altering salinity levels and
increasing turbidity. Although Malagasy reefs are relatively healthy now, our review
suggests that they could be particularly vulnerable to anthropogenic climate change in
part because of the potential for global warming to interact with other stressors already
impacting Madagascar coastal ecosystems.
25.1158
Coral Mortality And Recovery On A Jamaican North Shore Reef Following The
2005 Caribbean Region Bleaching Event
Peter GAYLE* 1 , Nigel WALTHO 2 , Bernadette CHARPENTIER 3
1 Centre for Marine Scences - UWI, Discovery Bay Marne Laboratory, St. Ann, Jamaica,
2 Biology, Carelton University, Ottawa, ON, Canada, 3 Research & Development,
DUWATECH, Ottawa, ON, Canada
In September 2005, extensive coral bleaching was observed on the north coast of Jamaica
which occurred in the wake of elevated sea surface temperatures observed in the
Caribbean region during the summer of that year. The local impact of this region-wide
bleaching event was monitored over a two year period commencing in November 2005.
Reefs at Dairy Bull, Rio Bueno and Discovery Bay on Jamaica’s north shore were
surveyed using photo transects. The purpose of this study was to determine the extent of
the coral bleaching at all sites and to assess species specific mortality and recovery as a
function of abundance, time and depth. Bleached and healthy corals (220) were tagged at
depths ranging between 8.5m and 36.6m and their condition monitored over time. The
mean incidence of bleaching at all three locations decreased from 60.4% (±23.5 SD) to
22.2% (±12.9 SD) during the monitoring period. Initial bleaching observed on the
Discovery Bay west fore reef was 63.9% (±15.5 SD) for shallow water (8.5m) in contrast
to the 80% (±5 SD) bleaching observed at 24.4m and 36.6m depth. By August 2006, the
numbers had decreased to 10.3% (±7.3 SD) for the shallow and 17.6% (±2.1 SD) for
deep corals. Complete or partial mortality of tagged corals in shallow water was 21% and
14% for corals tagged at deeper sites. Agaricia and Montastrea spp. were most affected in
shallow water. At depth, A. grahamae was most affected by bleaching. Montastrea spp.
appeared more robust whereas the Porites spp. were less hardy than their shallow water
counterparts. Further studies are required to investigate the relationship, if any, between
depth and the resilience and ability of various coral species to withstand the impacts of
repeated bleaching events.
25.1159
Coral Bleaching And Spatio-Temporal Variation Of Thermal Stress in Shiraho Fringing
Reef Of Ishigaki Island, Southwest Japan
Kazuo NADAOKA* 1 , Takahiro YAMAMOTO 2 , Kazuma ARISAKA 2 , Yuji MAEDA 2 ,
Shunsuke MOTOOKA 2 , Hajime KAYANNE 3 , Satoshi MAEKAWA 4 , Enrico PARINGIT 5
1 Department of Mechanical and Environmental Informatics, Tokyo Institute of Technology,
Tokyo, Japan, 2 Tokyo Institute of Technology, Tokyo, Japan, 3 University of Tokyo, Tokyo,
Japan, 4 WWF-J, Okinawa, Japan, 5 University of the Philippines, Quezon, Philippines
Significant coral bleaching occurred in theYaeyama islands southwest Japan in 2007 summer.
To examine detailed characteristics of spatio-temporal variation of thermal stress in a reef and
their relationship to the coral bleaching, we made a field survey at Shiraho, a well-developed
fringing reef located in the southeast coast of Ishigaki island, in 2007 summer by deploying data
loggers of water temperature at 23 points in the reef and 1 point outside the reef. The data was
analyzed and compared with the data in 2003 summer obtained by a similar field survey at the
Shiraho reef. We made also computational analyses of water temperature variation both in time
and space around the reef based on a hydrodynamic and thermal transport model. Besides we
performed satellite image analyses to detect coral bleaching distribution in more detail. In 2007
the daily mean temperature outside the reef was around 29°C until July 20 and then rose up to
30.5°C in late July. In the reef the daily mean temperature rose up to about 33.5°C in late July
and even the daily lowest temperature exceeded 30°C in the wide area of the reef. Concurrently
with this trend of the water temperature in the reef, the coral beaching started to develop
extensively in late July. Obviously the significant water temperature elevation indicates the
importance of local thermal effects due to shallow topography. Moreover the numerical
simulation analysis clarified that the water temperature increase in the reef was augmented by
an atmospheric effect; i.e., in late July 2007 the wind became so small that the latent heat flux to
the air was decreased. The spatial distribution of the coral bleaching in the reef was found well
correlated with the thermal stress distribution, which was appreciably influenced y the local
hydrodynamic circulation.
25.1160
Investigating Spatial Variation in Coral Recruitment With Respect To Temperature
Along The Southern Coast Of St. John, Us Virgin Islands
Daniel GREEN* 1 , Peter EDMUNDS 1,2
1California State University, Northridge, CA, 2California State University, Northridge
Studying the effects of physical environmental factors on scleractinian corals has been
popularized by the increased frequency of thermal bleaching, however few studies have
documented the effect of temperature on coral recruitment. The goals of this study were to test
for kilometer-scale variation in seawater temperature and coral recruitment on the southern
coast of St. John, US Virgin Islands, and to explore the extent to which temperature might be
influencing coral recruitment. To measure temperature and recruitment, a logging thermistor
and settlement tiles were deployed at 5-6 m depth at 10 sites in August 2006. Thermistors and
settlement tiles were replaced and analyzed every six months in order to capture seasonal
variation in biological and physical events. The two sampling periods occurring between
August 2006 and July 2007 revealed strong east-to-west relationships in temperature and
densities of coral recruits, which is likely a result of the prevailing westward water current. In
both sampling periods, the abundance of coral recruits differed significantly among sites, with
mean densities declining from ≈ 1.7 recruits tile-1 in the east, to ≈ 0.4 recruits tile-1 in the west.
Seawater temperature also varied significantly among sites over both sampling periods, and this
effect was reflected in greater daily variation in temperature at western sites compared to
eastern sites. Together, through a significant negative correlation between daily variation in
temperature and coral recruitment, these results suggest that small-scale variations in
temperature are associated with the rate of coral recruitment in St. John. If this relationship
applies to larger spatial scales, then it might provide insights into the causes of variation in coral
recruitment throughout the Caribbean.
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