21.   Coral reefs provide vital marine ecosystems for fisheries and wildlife.

22.   Conservation International, based in Washington, D.C., is devoted to protecting plant and animal diversity in major tropical wilderness areas and key marine ecosystems.

23.   He said the dredging might also cause fishing jetties and platforms to collapse as well as destroy the marine ecosystem.

24.   The area contains all the elements of a Caribbean tropical marine ecosystem, officials said.

25.   The impact has been devastating to coral reefs and other delicate marine ecosystems, water quality and human health.

26.   The organization also said that allowing whales to multiply freely would harm the marine ecosystem because they consume so much fish.

27.   The organization also said that not curbing whale numbers would harm the marine ecosystem because they consume so much fish.

28.   The marine ecosystems are also crucial in maintaining the desirable proportion of gases in the atmosphere.

29.   While Okinawans have long been pushing to move the heliport offshore, environmentalists say reclaiming land over a reef would damage the marine ecosystem.

30.   The submarine will be powered by battery, so the fragile marine ecosystem will not be fouled by exhaust fumes or fuel leaks.