11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 10: Ecological Processes on Today's Reef Ecosystems
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Leptoseris in Hawaii: The Deepest Photosynthetic Corals In The World?
Samuel KAHNG* 1 , James MARAGOS 2 , Eric HOCHBERG 3 , Richard KLOBUCHAR 4
1 College of Natural Science, Hawaii Pacific University, Kaneohe, HI, 2 Pacific/Remote
Islands National Wildlife Refuge Complex, U.S. Fish & Wildlife Service, Honolulu, HI,
3 Hawaii Institute of Marine Biology, Kaneohe, HI, 4 Waikiki Aquarium, Honolulu, HI
Despite its ecological importance, the photosynthetic deep reef below 50 m around the
world is poorly understood. Most coral reef science is performed well within the depth
limits of recreational SCUBA diving. However, zooxanthellate scleractinian corals occur
far below these depths in clear, oligotrophic waters. In Hawaii, photosynthetic corals
have been observed growing in situ down to 153 m off the Big Island. Around most of
the Main Hawaiian Islands, there is extensive deep reef habitat associated with the insular
shelves which extend laterally several km offshore to depths of 100-120 m where they are
typically bordered by steep fossil carbonate slopes. In 2001-2006, HURL deep-water
surveys in Hawaii observed that the dominant shallow-water reef building corals (i.e.,
Porites, Montipora, and Pocillopora) were rare below 60 m. However, zooxanthellate
scleractinians of the genus Leptoseris were abundant between 60-120 m. In many areas,
coral cover exceeded 50% providing complex habitat for an abundance of reef fish and
invertebrates. To date, taxonomic analysis has identified Leptoseris hawaiiensis,
Leptoseris yabei (new record for Hawaii), and at least two undescribed, congeneric
species. Observations suggest that Leptoseris spp. possess specialized photosynthetic
physiology for thriving in low light. Preliminary analysis on colonies in culture at the
Waikiki Aquarium in Honolulu, Hawaii suggest that the coral growth rates are
comparable to shallow-water corals, photosynthesis is the primary source for energetic
requirements, and pigment densities are an order of magnitude higher than shallow-water
corals. Further research into distribution, physiology, and ecology are needed to properly
manage this understudied but important habitat. In particular, examining the
environmental factors determining lower depth limits will provide insight on how these
important habitat builders will react to future changes in climate and optical water
quality.
10.322
Sea Urchin Herbivory in Hawaiian Shallow Water Ecosystems: echinothrix As
Allies With tripneustes
Holly JESSOP* 1 , Misaki TAKABAYASHI 1 , Marta DEMAINTENON 1 , Camille
BARNETT 1 , Nate OLSON 1
1 Marine Science, University of Hawai`i at Hilo, Hilo, HI
Tripneustes gratilla sea urchins have been shown to be important grazers on Hawaiian
coral reefs, helping to prevent overgrowth of algae and also significantly consuming
invasive algal species that have become problematic in Hawai‘i. To add to this body of
knowledge, we have conducted research on herbivory by Diadematid Echinothrix
urchins, which co-exist with T. gratilla and are also prevalent on Hawaiian reefs. The
objective of this research was to assess the comparative and combined potential grazing
impacts of T. gratilla and Echinothrix species on invasive algal populations in Hawai‘i.
Our research program utilized three different methodological avenues: 1) laboratory nochoice
feeding trials of two-week duration to quantify grazing rates on the invasive algae
Gracilaria salicornia, 2) ecological field surveys to measure urchin abundances and to
investigate interspecific habitat partitioning, and 3) isotope analyses to determine relative
urchin trophic positions and in situ feeding habits. Our results of urchin grazing rates that
are significant and similar, differences in spatial distribution on reefs, and no evidence for
in situ partitioning of food resources, suggest that Echinothrix species may be important
allies with T. gratilla in the control of algae in Hawai‘i. These results should be useful to
conservation managers working to understand and prevent coral reef degradation and
macroalgal phase shifts in Hawai‘i.
10.323
The Ecological Significance Of The Spotted Spiny Lobster And The Long Spined Sea
Urchin On Patch Reef Communities in The Florida Keys
Meredith KINTZING* 1 , Mark J. BUTLER IV 1
1 Biology, Old Dominion University, Norfolk, VA
The degradation of coral reefs in the Caribbean has been attributed to many factors including
global climate change, disease, eutrophication, overfishing, and sea urchin (Diadema
antillarum) mass mortality. For example, the loss of piscine predators and herbivores to
overfishing is thought to dramatically alter coral reef community structure. However, large
invertebrate predators, such as lobsters, are also heavily exploited and their impact on coral reef
communities is largely unknown. In the Caribbean, the Spotted Spiny Lobster (Panulirus
guttatus) is an abundant resident of shallow reefs and a omnivorous predator of echinoderms,
crustaceans, polychaetes, and other benthic taxa. Panulirus guttatus is an obligate dweller of
reefs and displays high site fidelity, so unlike other sympatric species of lobster, it is more
likely to directly impact reef communities. We are investigating the trophodynamics of P.
guttatus on patch reefs in the Florida Keys (Florida, USA) and are experimentally testing the
hypothesis that high densities of P. guttatus inhibit recovery of D. antillarum via predation on
urchin recruits. Our study couples gut content analysis, laboratory feeding trials, and
manipulative field experiments. Preliminary results indicate that in situ changes in lobster
density, hence predation, alters the composition of reef macroinvertebrate communities. Our
initial laboratory studies also show that Diadema display strong behavioral responses to lobster
chemical cues, which may result in changes in macroalgal community structure on reefs.
10.324
Secondary Succession Of Coral Reef Communities At Urasoko Bay, Ishigaki Island, The
Ryukyus (Southern Japan)
Hideo OHBA* 1 , Kazumasa HASHIMOTO 2 , Kazuyuki SHIMOIKE 3 , Takuro SHIBUNO 2 ,
Yoshimi FUJIOKA 4
1 Department of Marine Biosciences, Tokyo University of Marine Science and Technology,
Tokyo, Japan, 2 Ishigaki Tropical Station, Seikai National Fisheries Research Institute, Okinawa,
Japan, 3 Japan Wildlife Research Center, Tokyo, Japan, 4 National Research Institute of
Aquaculture, Mie, Japan
We need to clarify the causes of coral reef death and their recovery processes for the restoration
of dead coral reefs. Observations of secondary succession of coral reef communities was carried
out at Urasoko Bay, Ishigaki Island, the Ryukyus, southern Japan from 1995. Three study sites
were established in Urasoko Bay: outer reef flat (Sta. A), inner reef flat (Sta. B) and inshoreside
moat (Sta. C). Four permanent quadrats (1 m x 1 m) were put on each site and all
organisms were scraped from the substrate surface in all quadrats in March 1995. The percent
cover, number of species and colonies of hermatypic corals as well as the percent cover of
marine algae in each quadrat were measured once a year. Except some quadrats at Sta. B and C,
whose substrata are composed of rubble from dead branching corals, the immigration of coral
larvae and the cover of hermatypic corals gradually increased toward summer of 1998, but most
colonies of Acropora spp. died during large-scale coral bleaching between summer and fall of
1998. However, new coral recruitment started again and the coral cover at Sta. A and B
achieved 90-100% during 2004-2005. Coral species recruited on the rocks at Sta. A and B were
tabular and corymbose Acropora spp. and those at Sta. C were massive Porites spp. in both
recovery periods. Thick non-articulated coralline algae covered the rock surface for 2-3 years
before the recovery of hermatypic coral communities. It is suggested that the non-articulated
coralline algae play a role in construction of firm substrata for settlement and growth of
hermatypic corals on the dead corals. The tabular Acropora community around the healthy
outer reef flat in Ishigaki Island seems to recover fully in 6-7 years.
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