The result is that coral is limited to shallow areas where sunlight can adequately penetrate, largely in subtropical waters. .

             Despite the vast amount of coral, that can seem mind-boggling at times, the specific environmental conditions required by coral means that it can be very susceptible to environmental changes. For examples, relatively minor surface water temperature increases can kill, or bleach, coral reefs. In Hawaii Jokiel and Brown (2004) found that sea surface temperature increases of just more than 1 degree C caused significant coral bleaching in both 1996 and 2002. They observed that the overall trend of oceanic warming is causative for increases in the frequency and severity of coral bleaching worldwide. While global warming has been pointed to as the reason for this increase, there are more direct ways that man is placing new environmental stresses on coral reefs. Illegal fishing with explosives in Southeast Asia has extensively damaged coral reefs there. The explosions kill fish, but also shatter coral skeletons, which bury or abrade living coral (Fox et al., 2005). This prevents recovery in addition to the initial damage. Man's activities on land and sea continue to place new stress on the coral ecosystem. These stresses include offshore drilling, limestone mining, mercury pollution, nitrogen pollution from agriculture, passing ships, and tourism (Forsman, 2005). Collectively, these threats all undermine the integrity of coral reefs worldwide and challenge the long-term survival of this ecosystem.

             Though less known, mangrove swamps also face significant environmental stress. The harshness of the environmental conditions of this ecosystem constitutes one stressor. However, just as with coral reefs, anthropogenic causes can be highlighted as direct stresses upon the ecosystem and the life that inhabits it. In the tropics and subtropics, mangrove swamps border muddy seacoasts, providing a thick band of life between the sea and inland ecosystems.