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Abstract CELLULAR BIOMARKERS AS A MEASURE OF SUB-LETHAL STRESS IN CORAL LARVAE Raphael Ritson-Williams, Cliff Ross and Valerie
J. Paul. As coral reefs across the Caribbean decline in coral cover, coral
larval recruitment is a key process that will aid in the recovery
of coral reef communities. Elevated temperature is known to inhibit
larval coral recruitment, however few experiments have evaluated
the mechanisms of temperature stress on coral larvae. Short term
exposure of Porites astreoides larvae to elevated temperatures
(+3.5°C for 4.5 h) induced significantly more reactive oxygen
species and upregulated the enzymes catalase and superoxide dismutase
compared to 27°C seawater temperatures. In addition the larvae
had reduced settlement and increased mortality after the heat treatment.
Our results indicate that even short term exposure to thermal stress
can induce antioxidant enzyme activity and causes a lethal and sublethal
reduction in recruitment of coral larvae. CORAL RECRUITMENT IN THE GARDENS OF GOOD AND EVIL Raphael Ritson-Williams1, Suzanne Arnold2,
Robert S. Steneck2, and Valerie J. Paul1 Coral reefs are losing coral cover on a global scale, but improving
natural coral recruitment is one management strategy that could
reverse this trend. In order to better understand where and why
coral larvae settle we tested settlement preferences of corals in
the field and in the laboratory. Our field research suggests that
settling coral larvae select some biological substrates such as
coralline algae, which they settle on and near. Of the three spawning
coral species that we tested in the laboratory, each one had different
settlement rates in response to different species of coralline algae.
Sponges, invertebrates and macroalgae, which can overgrow coralline
algae in the field, are known inhibitors of coral recruitment. Increased
herbivory may be a mechanism to shift the benthic community composition
away from coral recruitment inhibitors towards facilitiators such
as coralline algae, thus providing managers a strategy for improving
the benthos for higher rates of coral recruitment. |