Coral Reefs: Cycle A
When one thinks of the earth’s lithosphere one may not think to look past the terrestrial portion of the earth in the form of the earth’s continents. If we take a closer look at what lies underneath the sea we realize that the earth’s tectonic plates extend out into the depths of the ocean where an entire underwater world exists. According to the Vision Learning on-line Glossary the lithosphere is defined as “The rigid upper layer of the earth consisting of the crust and the upper mantle. The earth’s tectonic plates are composed of pieces of the lithosphere. The lithosphere ranges in thickness from 10-12 km underneath the oceans to 70-200 km at the continents.”
The sediment that flows through the terminal rivers into the ocean is a component of the earth’s lithosphere. Minerals in the form of particulate become eroded, broken down and refined, transforming them from their parent material. These particles then end up in the ocean contributing some effect on the local environment. Particulates in the form of blowing dust from the continents are also a contributor to oceanic environmental change. Human activities on land take their toll on the earth’s surface creating finer particulates that are either carried away by atmospheric processes or converging rivers and streams that ultimately end up in the shallow waters of the sea and ocean.
If we focus and further examine the landscape beneath the sea we begin to realize that the sea is an entire world separate of our own on dry land. Even more specifically, the world of coral reefs at shallow depths holds an abundance of life that is interwoven in a sensitive ecological balance. A change on the earth’s terrestrial lithosphere could affect the essential balances needed by coral colonies in the shallow depths of the sea. According to an essay published by NOAA (2007) “excessive runoff, sedimentation, and pollutant discharges can result from dredging and shoreline modifications, coastal development activities, agricultural and deforestation activities…” NOAA’s Coral Reef Information System further states that reefs are dependent on specific environmental conditions including “water clarity and light levels [which] generally must be consistent throughout the year for corals to grow.” One can surmise from this information that terrestrial activity resulting in the creation of blowing dust and sediment can greatly reduce the sunlight needed by the coastal coral colonies to live and thrive.
According to Morlock et al. (2005), in a paper published for an online resource compilation, “the death of a reef system under sediment stress proceeds in a series of steps.” The authors further state that “Lowered light input due to water turbidity causes shifts in the ecological pattern and depth of the more rapidly growing coral. Direct deposition on coral heads results in a selective loss of coral related to the tolerance of individual coral to sediment loading. This results in further shifts in the ecology.”
Man’s alteration of the terrestrial lithosphere clearly contributes to off shore marine life. Furthermore, sediment and dust contributes both directly and indirectly to the destruction of the coral reefs.
How do coral reefs help as natural water breaks?
Does the water break keep the coast from eroding away?
Does denitrification occure in the sea?
Does denitrification create a toxic environment in the vast sea?
Morelock, J., Boulon, K., Galler, G. (2005) Sediment Stress and coral Reefs, Coral Reef Systems. Retreived November 9, 2007 from http://geology.uprm.edu/Morelock/corgeol.htm
NOAA (2007). NOAA’s Coral Reef Information System. Retrieved November 9, 2007 from http://coris.noaa.gov/
Vision Learning Glossary (2007). Visionlearning Glossary. Retrieved November 9, 2007 from http://www.visionlearning.com/library/pop_glossary_term.php?oid=