11th ICRS Abstract book - Nova Southeastern University

14.507
Genetic variation of the hydrocoral Millepora alcicornis across the Caribbean
Dannise RUIZ RAMOS* 1 , Nikolaos SCHIZAS 1
1 Department of Marine Sciences, University of Puerto Rico at Mayagüez, Lajas, Puerto
Rico
The hydrozoan genus Millepora is an important component of tropical reef contributing
to the carbonate structure. Virtually nothing is known about the genetic polymorphism
and divergence within and between Millepora species in the Caribbean. In a region
where the alarming decline of scleractinian corals has attracted the attention of the
scientific community, research in Millepora biology is limited. The objective of this work
is to make a molecular characterization of the Millepora populations in the Caribbean
region.
Samples of Millepora alcicornis were collected from 11 localities across the Caribbean;
Honduras, Panama, Grand Cayman, Mona, Desecheo, Puerto Rico, Vieques, Culebra, St.
Thomas, Bahamas, Curaçao and Bermuda. We sequences approximately 550 base pairs
of the mitochondrial COI gene. Preliminary results from the COI analysis suggest high
variability within the populations (87.95%), an elevated number of haplotypes (98 out of
238 sequences) and lack of population structure (FST = 0.12). The single locus analysis
indicates a high degree of genetic connectivity between Caribbean wide populations of
Millepora alcicornis suggesting high dispersal rates. However, the medusa stage of
Millepora lasts just a few hours in the water column, limiting the dispersal potential of
Millepora. The absence of population structure contradicts our predictions stemming
from the early life history of Millepora.
14.508
Population Structure in The Brown Tube Sponge (agelas Conifera) in The Florida
Reef Tract And Caribbean
J.M. HESTER* 1 , V.P. RICHARDS 1 , K. FELDHEIM 2 , M.S. SHIVJI 1
1 National Coral Reef Institute, Oceanographic Center, Nova Southeastern University,
Dania Beach, FL, 2 The Field Museum, Chicago, IL., Chicago, IL
Sponges are broadly distributed, occur in a wide range of habitats, and comprise a
substantial amount of the biomass and macro-biodiversity on coral reefs. Despite their
ubiquity in reef ecosystems, their dispersal dynamics are largely unknown. Here we
report on gene flow and population structure for the common brown tube sponge, Agelas
conifera (Demospongiae, Poecilosclerida) in the Florida reef tract and Caribbean. Over
300 samples collected from ten geographically distinct locations throughout Florida and
the Caribbean are being analyzed for variation at eight microsatellite loci. Preliminary
results from screening four loci in 295 individuals from eight locations indicated
significant population structure overall (FST = 0.072; P = 0.0018) with a significant
heterozygosity deficit (FIS = 0.310; P = 0.001). Lower FST values occurred within the
Florida reef tract sites compared to those between Caribbean island locations suggesting
relatively greater gene flow within the Florida reef system. Significant isolation by
distance was not found to occur Caribbean-wide (r = 0.25; P = 0.14), nor within the
Florida reef tract (r = 0.39; P = 0.10). Fine scale population structure occurred among
sites separated by