'%Healthy Reefs for Healthy People - A Guide to Indicators of Reef Health and Social Well-being in the Mesoamerican Reef Region%'%by Melanie McField and Patricia Kramer%

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Status

Konrad Hughen

A study of annual growth bands from Belize corals

showed intense stress banding and a corresponding

significant decrease in growth rate correlating with

the extreme 1998 bleaching event32. Geochemical

data from the coral cores are being analyzed and

are expected to indicate an increase in storm-related

terrestrial input coinciding with Hurricane Mitch in

1998.

Preliminary results from these studies of long-term

trends indicate that coral growth rates may be

decreasing in the Sapodilla Cayes, while remaining

stable at Turneffe Atoll32.

Data

Data Needs

Additional data are needed to adequately assess

coral growth rates on a regional scale.

Usefulness

Examination of coral colony growth provides insight

into the life history dynamics of individual species.

The skeletons of long-lived, massive corals are useful

natural archives of past climatic and environmental

conditions.

Some studies have shown that coral tissue growth

is more sensitive than is skeletal growth to changes

in environmental conditions. Thus, the use of coral

Jessica Carilli

tissue properties may be better than skeletal growth

alone as an indicator of coral reef condition.

Coral growth rates have important repercussions

for overall reef accretion. An important control of

coral calcification (growth) is the seawater calcium

carbonate saturation state. Global environmental

change (specifically increasing atmospheric CO2) will

increase the accumulation of CO2 in surface waters,

acting to lower the seawater pH (i.e., increase its

acidity). Thus, coral growth rates may be the best

indicator of the effects (if any) of this acidification on

coral health.

The research equipment needed for growth rate

analysis is beyond the capacity of monitoring programs

in the Mesoamerican region. Partnerships, such as

that established between the Healthy Reefs Initiative

and Woods Hole Oceanographic Institution and

Scripps Institution of Oceanography, can facilitate the

collection of such data. Growth rate measurements

need not be repeated on a frequent basis (possibly

every decade).