Mangroves Are a Critical and Threatened Marine Resource

Beth Bader — Fri, 28 Mar 2008 02:26:36 +0000

Clearing of mangroves in the name of land reclamation — land to be used for shoreline development — is a worldwide activity. According to University of Virginia and University of Georgia scientists William Odum and R.E. Johannes, more acres of mangrove may have been cleared worldwide than any other type of area except desert, an estimated “many hundreds of thousands of hectacres.” Clearing often results in high, long-term costs of battling increased erosion.

Mangroves are not areas to be “reclaimed.” They not only belong where they are, but they are actively reclaiming and preserving land on their own. The whole process is cyclical, beginning with the mangroves’ role as recyclers, and ending with protection of the outlying coral reefs.

The Role of Mangroves in Protecting Coral Reefs
The reclaiming process is as simple as it is vital. The mangrove roots act as natural filters, trapping sediment and run off from the land, thus preventing or slowing erosion.

Removal of mangroves causes a chain reaction. If the mangroves are cleared the sediment and pollutants run unchecked into the sea grass beds. The nutrient-rich effluent promotes the growth of phytoplankton and filamentous algae, which, combined with the sediment clouds the shallow water and blocks out light necessary for sea grass beds to flourish. The environment becomes anoxic, and the sea grass ecosystem dies.

Oceans are Hurting: Thanks, Humans

Shirley Siluk Gregory — Thu, 14 Feb 2008 21:55:59 +0000

Most of Earth might be covered with water, but the large population of bipedal animals that crowd the planet’s land masses is doing its best to leave its imprint on the oceans as well.

A new study from the National Oceanic and Atmospheric Administration (NOAA) finds that humans have had a heavy impact on more than 40 percent of the world’s oceans. That’s an area of more than 55 million square miles, or more than 144 million square kilometers.

NOAA researchers combined data from about 17 different human activities — including fishing, fertilizer runoff, shipping and pollution — to generate a global map on how those factors are affecting the oceans.

The marine regions suffering the most include the East Coast of North America, the North Sea, the South and East China seas, the Caribbean, the Mediterranean, the Red Sea, the Persian Gulf, the Bering Sea and parts of the western Pacific. So far, the polar seas remain the least impacted (give climate change a little more time, though, and that could soon no longer be the case).

“The extent of human influence was probably more than any of us expected,” said Kenneth Casey, a co-author of the study, which will be published in tomorrow’s (Feb. 15) issue of Science.

In those areas, the ecosytems facing the greatest threats are coral reefs and seagrass beds, both of which are critical habitats or nursey grounds for fish, as well as coastal mangroves.

Maybe this latest study will help further weaken one of the arguments used by climate change deniers, the one that says humans are too puny to wreak large-scale damage to a planet the size of Earth. Puny, yes, but damaging? Without a doubt.

Green Options » mangroves

Mangroves Are a Critical and Threatened Marine Resource

Oceans are Hurting: Thanks, Humans