organ pipe corals), and Stylasterina (lace corals). Ornamental corals are species with ornate skeletal structures and include the fast-growing, branching corals like Acropora and pocillipora. Corals which are harvested for jewelry are black corals (Order Antipatharia) and precious corals (pink, gold, and bamboo corals). These types of corals are deepwater spices that occur at very low densities, are recruitment limited, and grow very slowly. Precious corals are generally extracted using destructive trawls and tangle-net dredges. Commercial extraction of corals has damaged essential reef habitats and is believed to be causing local depletions of rare species in some areas (The James W. Hyde BIOL 1040International Trade in Corals, 1998)Land-based sources of marine pollution pose the greatest threats to coral reefs because of their widespread impact on water quality. Accounting for 80% of all marine pollution, land based sources of marine pollution include coastal development, agricultural practices, industrial activities, and inland deforestation (Coral Reefs and Land-Based Sources of Marine Pollution, 1998). Ocean pollution poisons coral polyps. Pollution takes on many forms including oil slicks, pesticides and other chemicals, heavy metals and garbage.Fertilizer runoff and untreated sewage introduce added nutrients to coastal ecosystems. These elevated nutrient levels promote algae growth. Unfortunately, high concentrations of algae or solid sewage can overwhelm and smother the polyps. Under normal conditions, herbivores fish and some invertebrates keep the algae population in check, but overfishing has diminished populations of herbivorsDeforestation degrades more than just land habitats. Wh...
