'%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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E C O S Y S T E M ST R U C T U R E I N D I C AT O R S

ABIOTIC

Conservation Objective

Maintain water quality conditions that support healthy, sustainable coral reefs, mangrove forests and

seagrass meadows.

Threats

Main threats are primarily associated with coastal development (including direct impacts from

sewage contamination and urban run-off and indirect impacts of vegetation clearing along the coast),

deforestation, agriculture, aquaculture, mining and dredging. Some of these processes also mobilize

contaminants. Rising sea surface temperatures and ocean acidification, attributable to increasing

atmospheric CO2, are of growing concern.

Management Actions

Reduce sediment and contaminant runoff due to agricultural practices or coastal development.

Prohibit clearcutting of mangrove forests.

Monitor coastal development projects to ensure water quality standards are not violated.

Improve the treatment and disposal of human sewage.

Reduce marine pollution (e.g., from oil tankers, cruise ships).

Reduce the use of toxic chemicals that can adversely affect coastal areas (e.g., pesticides).

Investigate opportunities to restore or enhance water quality (e.g., restore natural drainage

patterns or replant deforested areas).

· Reduce activities contributing to global climate change.

· Develop and implement methods to better track water quality in the region.

Abiotic (that is, non-living) factors strongly influence

light from reaching corals on the sea bottom. These

life on a coral reef. Reefs require highly specific

sediments can also smother or abrade the corals and

environmental conditions, and corals, in particular,

inhibit larval recruitment. Leaky septic tanks release

have adapted to relatively narrow ranges of light,

nutrients that interfere with calcification, disrupt

temperature and substrate type. Reef development

the coral-algal symbiosis and promote the growth of

begins with settlement of reef-forming organisms on

benthic algae at the expense of corals.

a pre-existing hard surface in shallow, warm, well-

illuminated water.

Indicators selected to track abiotic factors are:

Many abiotic factors are important in controlling

Water Quality: Temperature, Salinity,

modern reef distribution. Small-scale controls

and Transparency

influence organisms at a reef-wide level (e.g., light).

Intermediate-scale controls function within ocean

Ocean Color (remote sensing)

basins and include physical oceanographic factors

(e.g., current patterns). Large-scale controls act on

S10

Sedimentation Rates

a global scale and long time periods (e.g., sea level

rise).

Some human activities can alter abiotic conditions

in ways that stress reef biota. For example, dredging

a shipping canal may "stir up" sediments that block