11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 26: Biodiversity and Diversification of Reef Organisms
26-5
Soft Coral Biodiversity And Distribution In The Western Indian Ocean: Gradients,
Function And Significance
Michael SCHLEYER* 1 , Yehuda BENAYAHU 2
1 Oceanographic Research Institute, Durban, South Africa, 2 Department of Zoology and
The Porter School of Environmental Studies, Tel Aviv, Israel
Soft corals (Octocorallia: Alcyonacea) constitute important reef benthos in the WIO, yet
relatively little is known of their distributional gradients, function or significance.
Integrated results of published surveys and of material recently collected as far afield as
the Chagos Archipelago manifest interesting gradients in their diversity, abundance and
apparent function. Reef disturbance may result in them becoming dominant, eliciting an
alternative stable state in some coral communities. While certain tropical taxa attenuate
from north to south, others attain their highest abundance at high latitude; the latter
appears to be related to their ability to tolerate more swell-driven turbulence. Once
established, soft corals appear to be persistent and long-lived, a characteristic also
reported in the literature. A long-term monitoring study has nevertheless revealed that
they appear to be vulnerable to climate change.
26-6
Vagile Coelobites Of Eastern Pacific Coral Reefs: Structurally Homogenous Reef
Environments And The Importance Of Substrate in Shaping Community
Composition
Ian ENOCHS* 1 , Gena HOCKENSMITH 1
1 Marine Biology and Fisheries, University of Miami, Miami, FL
Coral reef framework structures are complex three-dimensional habitats occupied by
diverse taxa. The term cryptofauna (coelobites) specifically applies to those organisms
that live within the interstices of coral reef framework. The remarkably diverse
assemblage of cryptic biota is poorly understood relative to that of the epibenthic and
nektonic reef species. It has been postulated that the biomass of this cryptic component
of the reef ecosystem is extremely high, possibly exceeding that of the surface biota, and
it is likely that coelobites are integral to reef nutrient dynamics. Furthermore, cryptic
animals that inhabit reef pore spaces may degrade coral skeletons, playing an important
role in bioerosion; the biogenic loss of reef framework. Thus, evaluating the interaction
of nutrient dynamics, bioerosion, habitat structure, cryptic biomass and biodiversity is
essential to understanding coral reef community responses to a changing climate.
Previously, the strong dependence of cryptic community composition on the size and
shape of the void-space habitat has limited extrapolation of studies to the “whole reef”
level. Pocillopora reefs of the eastern Pacific are structurally complex yet relatively
homogenous across a horizontal plane. This unique physical composition allows for the
possibility of replicate sampling of the coelobite community and a subsequently broader
scale analysis. In order to evaluate the dependency of cryptic community structure on the
nature of the substrate it occupies, both living and dead Pocillopora colonies were
defaunated and returned to the reef. After one year in situ, associated coelobites were
identified, weighed, and counted. Substrate preference (live vs. dead coral) was found to
be species specific. Biomass and abundance of vagile coelobites was significantly higher
in living coral colonies when compared to dead coral framework. These findings have
important implications for how reef communities may respond to coral mortality.
26-7
Coastal Fish Communities of the Socotra Archipelago: “Pseudo-Reefal” Diversity and
Ecology Without Coral Reefs.
Uwe ZAJONZ* 1 , Dr. Friedhelm KRUPP 1
1 Ichthyology, Senckenberg Research Institute and Natural History Museum, Frankfurt a.M,
Germany
Between 1999 and 2007 shallow water fish communities of the Socotra Archipelago (Gulf of
Aden, NW Indian Ocean) were studied with the objective of assessing patterns of diversity and
abundance, community composition, trophic structure and biogeographic affinities. The
Archipelago hosts very diverse, varied and biogeographically unique coral and fish
communities. About 730 fish species in 110 families have been recorded from the Archipelago
as yet. The structure of the dominant shallow water fish community types, as inferred from
species composition, trophic analysis and correlation analysis of fish and benthic communities,
is comparable with typical “reef fish” assemblages of the Western Indian Ocean. Despite the
fact that the Archipelago has only few biogenic reefs, the species numbers within certain reef
fish taxa exceed those known from the entire neighbouring Red Sea. Research on tropical
marine communities typically focus on reef habitats with high cover of scleractinian corals and
the presence of so-called “reef-associated” fish species, based on the postulate that these are
dominating factors in determining coastal diversity in the tropics. Results of the present study
suggest that, besides classical coral reef assemblages, equally diverse benthic and associated
fish communities can evolve, if the local “mix” of abiotic and biotic variables is suitable. These
include mesoscale habitat heterogeneity and complexity, i.e. availability, connectivity among
these habitats and among wider biogeographic units, and probably productivity. Being exposed
to a harsh monsoon regime, Socotra’s coastal ecosystems are heterogeneous and dynamic in
space and time, giving rise to a great variety of ecological niches and thus supporting corals and
fishes from many different ‘walks of life’. Consequently, more consideration needs to be given
to studying population dynamics, connectivity and biogeography of such marginal “pseudoreefal”
communities.
26-8
Molecular Data Suggest An Indo-Pacific Origin Of The Invasive Snowflake Coral
(Carijoa Riisei) in The Hawaiian Archipelago And Refute A Caribbean Introduction
Gregory CONCEPCION* 1 , Samuel KAHNG 2 , Marc CREPEAU 1 , Erik FRANKLIN 1 , Steve
COLES 3 , Robert TOONEN 1
1 Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI,
2 Oceanography, University of Hawaii at Manoa, Honolulu, HI, 3 Natural Sciences, Bishop
Museum, Honolulu, HI
The first published report of the invasive snowflake coral in Hawaii comes from Pearl Harbor in
1972. Subsequent identification of this species as the Caribbean octocoral Carijoa riisei led
to the general conclusion that it was introduced via contemporary maritime vectors. In an
attempt to confirm the source of the Hawaiian population, we used mitochondrial (h = 0.8379; π
= 0.0022) and nuclear (H = 0.8904; π = 0.0299) data to compare Hawaiian specimens with
Carijoa samples collected worldwide (n=248). In addition, vessel traffic patterns for the
Pacific Ocean were examined for 1940-1979 to determine maritime connectivity to and from
Hawaii during the assumed time of introduction. Combined mitochondrial and nuclear data
show both higher and considerable unique genetic diversity within the Indo-Pacific compared to
samples from throughout the Caribbean-Atlantic, suggesting that the species is native to the
Indo-Pacific. Further, isolation-by-distance (IBD) analysis indicates a significant correlation
between genetic and geographic distance in both the Indo-Pacific and Hawaii, but not for the
Atlantic, and coalescent estimates for the Atlantic are the lowest of the three populations.
Finally, C. riisei sampled from throughout Hawaii (n=96) share none of the Caribbean mtDNA
haplotypes (29 unique haplotypes) and only a single nDNA allele (of 29 unique alleles),
indicating that the Hawaiian populations derive from Indo-Pacific rather than Caribbean-
Atlantic origins. Despite an active commercial vessel route between Hawaii and the Panama
Canal, we find no evidence to support a maritime introduction of Carijoa riisei from the
Caribbean-Atlantic.
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