11th ICRS Abstract book - Nova Southeastern University

Poster Mini-Symposium 10: Ecological Processes on Today's Reef Ecosystems
10.375
Effects of Sedimentation on the Distribution and Ecology of the Reef Zoanthid
Palythoa caribaeorum
Veronica ACEVEDO* 1 , Paul YOSHIOKA 2 , Wilson RAMIREZ 3
1 Marine Sciences, University of Puerto Rico, Ponce, Puerto Rico, 2 Marine Sciences,
University of Puerto Rico, Lajas, Puerto Rico, 3 Geology, University of Puerto Rico,
Mayaguez, Puerto Rico
The present study determines different aspects of the ecology of the zoanthid Palythoa
caribaeorum in various coral reefs at La Parguera, southwest coast of Puerto Rico. On
each reef 4 different depth zones were selected; reef crest, shallow reef front, deep reef
front, and the sand plain. Three 1 x 10m (10m2) transects were surveyed in each zone to
estimate densities, size-frequency distributions and percent cover of Palythoa. Studies of
the effects of sedimentation on the distribution of Palythoa were performed in Enrique
and Media Luna reefs. Percent coverage of Palythoa was highest in the crest zone and
decreased with depth at both reefs. Colony densities were not significantly different
among reefs or zones. Size frequency distributions were dominated by small colonies
and were significantly different among reefs and zones. Water column sedimentation
rates were significantly higher in Media Luna compared to Enrique, but depth-related
patterns differed between reefs. Sedimentation rates were greatest in the shallow crest
zone at Enrique, but at Media Luna were greatest in the deep sand plain zone. These
patterns may be caused by the resuspension of the sediments. Bedload transport was not
statistically different between Enrique and Media Luna. At both reefs the highest
bedload transport occurred in the sand plain zone followed by the crest zone and the reef
front. The results do not show any correlation between Palythoa percent coverage and
water column sedimentation. There is an adverse relationship of Palythoa percent
coverage and bedload transport. The relatively high abundances of Palythoa and high
bedload transport in the reef crest may be the result of strong wave action that cleans
excess sand off colony surfaces. Alternatively, bedload transport accumulates and buries
Palythoa colonies in the sand plain areas.
10.376
Trophic Cascades On Caribbean Coral Reefs: Invasive Lionfish (Pterois Volitans
And P. Miles) Predation On Cleanerfish in The Bahamas
Stephanie GREEN* 1 , Isabelle CÔTÉ 1
1 Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
Invasive species are an emerging anthropogenic stressor threatening coral reef
community assemblage and species diversity. Since 2004, two species of venomous,
piscivorous Indo-Pacific lionfish (Pterois volitans and P. miles) have invaded coral reef
communities in the Bahamas. The ultimate impact of these predators on Caribbean coral
reef fish communities will depend on the importance of the species they interact with in
maintaining the structure of reef food webs. Our analyses of lionfish stomach contents
from patch reefs around New Providence, Bahamas, revealed a high prevalence of
predation on cleanerfish species, including both obligate cleaning gobies and a range of
facultative cleaners. Comparisons of dietary contents to prey availability on the reef
suggest preferential predation on cleaners. Cleanerfish can dramatically reduce
ectoparasite loads of their clients, and have been shown, at least in the Indo-Pacific, to
drive patterns of reef fish diversity. To examine whether lionfish trigger a disturbance in
Caribbean reef fish community assemblages through predation of cleaners, we measured
the densities of lionfish, cleanerfish and fish clients on patch reefs around New
Providence. Overall cleanerfish density was inversely correlated with lionfish density,
and client fish diversity but not abundance, covaried positively with cleaner density, but
negatively with lionfish numbers. These results suggest that the lionfish invasion may
affect reef fish diversity by disrupting an important symbiotic relationship. Thus, lionfish
could trigger quantifiable trophic cascades on coral reefs as they continue their rapid
spread around the Caribbean.
10.377
Effect Of Short-Term Nutrient Enrichment On Photosynthesis in Crustose Coralline
Algae
Cheryl SQUAIR* 1 , Celia SMITH 1
1 Botany, University of Hawaii, Honolulu, HI
Crustose coralline algae (CCA) are important components of reef ecosystems. They provide
substrate stability, are major producers of sand and provide settling cues to a variety of
invertebrates, including many species of coral. Owing to their slow growth and a lack of basic
ecophysiological data, few studies have examined how this important group of organisms will
be affected by anthropogenically-induced changes in their environment. Previous studies have
suggested that crustose coralline algae are chronically photoinhibited under the high light
conditions experienced on tropical reef flats. Nutrient availability is an important factor
affecting whether components of the photosynthetic apparatus damaged under high light can be
repaired. Under conditions of low nutrient availability, insufficient nitrogen may be available to
effectively repair damage caused by high irradiance. Plants suffering chronic photoinhibition
may be more susceptible to assaults such as disease and rising temperatures. Therefore,
understanding the physiological dynamics of CCA in the field is critical to understanding how
they may respond to future global change. This study sought to examine how nutrients affect
the photosynthetic physiology of CCA in a high light backreef area of the near-pristine fringing
reef of Ofu, American Samoa. Pulse Amplitude Modulated (PAM) Fluorometry was used to
measure relative photosynthesis in CCA with and without experimental nutrient enrichment,
over a six-week period, at 10 haphazardly selected sites on the backreef. Using a diving-PAM,
estimates of the physiological parameters: α, EK and ETRmax were made to assess how shortterm
nutrient enrichment influences the physiology of these important reef calcifiers. Our
results suggest that in this low nutrient, high herbivory system, nutrient enrichment may help
alleviate photodamage associated with high light environments.
10.378
Preliminary Findings: Can Invasive Macroalgae Facilitate Invasional Meltdown?
Rodolf PAN* 1 , John STIMSON 1 , Celia SMITH 2 , Durrell KAPAN 3
1 Zoology, University of Hawaii at Manoa, Honolulu, HI, 2 Botany, University of Hawaii at
Manoa, Honolulu, HI, 3 CCRT, University of Hawaii at Manoa, Honolulu, HI
Gracilaria salicornia (C. Agardh) E. Y. Dawson (rhodophyta) is native to the Philippines, and
was unintentionally introduced to the Hawaiian Islands before the 1950s. It is one of five
macroalgal species considered invasive on Hawaiian coral reefs. Gracilaria salicornia appears
to have the ability to monopolize substrata and out-compete or exclude other species of
macroalgae. In Waikiki, Oahu, it has become the dominant macroalga in an area that used to
support over 60 species of native macroalgae. Gracilaria salicornia functions as a habitat
architect, creating a three-dimensional matrix with its interwoven thalli, and forming dense
‘mats’ that contain an extensive epifaunal community. The species composition of this
community appears to be distinct from surrounding sand and coral rubble substrate.
Observations have revealed many motile and sessile invertebrates within its ‘mats’, some of
which are non-indigenous and considered invasive, e.g. the black sea squirt (Phallusia nigra),
Herdman’s sea squirt (Herdmania momus), an unidentified red sponge (Mycale sp.), and the
Philippine mantis shrimp (Gonodactylaceus falcatus). Hawaiian sea-grasses are not luxuriant or
tall enough to create much habitat among their foliage, and G. salicornia appears to create a
novel habitat on Hawaiian reefs. It may be providing a habitat for organisms which utilize sea
grass beds or dense algal mats in other global locations. This project explores whether the
invasion of a habitat architect such as G. salicornia could encourage the persistence or invasion
of other non-indigenous species, and facilitate synergistic interactions with, and between, these
aliens. These synergistic interactions may create momentum in a positive-feedback loop,
causing accelerating damage to ecosystems, and eventually resulting in the alteration or
destruction of native communities and coral reef ecosystems - invasional meltdown.
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