Some scientists believe that human actions are increasing greenhouse gases (gases like carbon dioxide that let in almost all the sun's radiation, but block much of the outgoing radiation from Earth). They call this global warming. They believe the Earth's atmosphere is getting warmer. If true this could upset the delicate balance of temperatures that coral reefs need to thrive.
Coral reefs are important in determining the amount of carbon dioxide in the atmosphere. The zooxanthellae algae, through photosynthesis, remove carbon dioxide from the air and make carbohydrates available as food for both the zooxanthellae and the coral polyps. Eventually, much of the carbon removed from the air will reside on the ocean bottom in the form of limestone produced by coral polyps. However, both the coral polyps and the zooxanthellae must also use oxygen through the process of respiration (the same process humans use in breathing). Respiration releases carbon dioxide into the ocean and atmosphere. During the day when photosynthesis is occurring, more oxygen is produced by photosynthesis than carbon dioxide by respiration. At night, however, photosynthesis stops, and only respiration goes on. Most scientists believe coral reefs remove more carbon dioxide from the air than they addcertainly a good thing. Pie Chart: Proportion of human activities that contribute an increase in greenhouse gases.
There is some evidence that larger amounts of iron may be deposited in the ocean in the future as global warming
results in more windblown continental dust. Theoretically, sea spray and water vapor form low
Maintained by ETE Team
Exploring the Environment®, Coral Reefs was developed under a cooperative agreement with NASA.
Some images © 2004 www.clipart.com
Center for Educational Technologies, Circuit Board/Apple graphic logo, and COTF Classroom of the Future logo are registered trademarks of Wheeling Jesuit University.