Climate
change has been hypothesized as a driver of recent increases in the prevalence
and impacts of coral diseases. Little is
known about the mechanism through which environmental stressors like temperature
influence host resistance and overall disease dynamics. In this study we
examined biochemical and cellular immune parameters in two species of coral
during a naturally occurring temperature anomaly. In the summer and fall of
2005 water temperatures in the Caribbean were
the highest levels recorded in the last century and resulted in a major coral
bleaching event with subsequent disease outbreaks. Using corals collected from field
sites in Puerto Rico and the Florida Keys we
evaluated the effects of this climate anomaly on coral immunity and disease
dynamics. Activities of known immune proteins such as prophenoloxidase,
lysozyme and anti-bacterial activity were monitored
in the reef building coral Montastraea faveolata. As a measure of cellular immunity, amoebocyte concentrations were monitored in the gorgonian
coral Gorgonia ventalina. In
this paper we present data demonstrating that some components of immunity
respond to natural temperature stress as predicted and are suppressed, while
others are actually activated by elevated temperatures, suggesting a general
stress response or resilience to a changing environment.