But the reefs around Quintana Roo
have not escaped the global coral reef
crisis, and are in a state of serious de-
cline. Among the coral species most
affected is Elkhorn Coral (Acropora
palmata). A. palmata is a so-called key-
stone species, as it is one of the major
reef builders that form the framework
of the reef around which many fish
and invertebrate species dwell. A major
cause of the observed coral mortality
is coral bleaching, which is currently
wreaking havoc on Caribbean reefs.
Hot summers cause surface waters to
rise above 90ºF, disrupting the fragile
symbiosis between coral and algae and
triggering massive bleaching events. At
these high temperatures, the symbiotic
algae known as zooxanthellae sustain
right: a lagoon near Puerto Morelos,
covered in seagrass beds ( Thalassia
hemprichii). Here, corals start to appear
several hundred meters off the coast.
Below: Two neighboring brain corals
(Diploria strigosa), each over 3 feet in
diameter. The colony in the front seems to
be recovering from a bleaching event.
