The problems with run-off

Friday, March 11th, 2011

With all the rain and the ensuing run-off these past few months, the RMP received many questions about the effects of sedimentation on the reef. The earliest coral reef researchers recognized that coral growth was strongly inhibited wherever muddy freshwater enters the sea. Negative impacts of rivers include the introduction of freshwater and sediments such as mud, silt, and clay. While freshwater can cause bleaching, excessive sediment smothers and kills coral. Corals differ greatly in their ability to resist sedimentation, however most species are highly intolerant of even small amounts.

Unfortunately for the coral of Roatan, increases in development often worsen sedimentation. One of the main culprits is coastal dredging, like that which has occurred in Mahogany Bay and French Cay. Dredging generates huge muddy plumes which smother reefs in areas that previously had clear water. These plumes continue to cause damage long after the dredging has ceased as the mud is re-stirred by every storm, causing clouds of sediment to slowly work their way down coastlines, damaging reefs many times more before they are washed away.

The other main cause of sedimentation is soil erosion caused by increased deforestation and development. Depending on rainfall, topography, soil types, and land management, deforestation and development can result in up to thousand-fold increases in sedimentation in near shore waters. As a result sedimentation is taking a severe toll on almost all coastal reefs worldwide. In healthy coastal watersheds, sediments are naturally removed from fresh water before it enters the sea. Plants such as grass, trees, and mangroves act as buffers between the land and the sea by trapping sediment. If the natural buffer zones are damaged, sediment runs straight out onto the reef.

Roatan’s soil is composed mainly of red clay, which is easily soluble. After a heavy rain, it’s easy to see the threat to the reef as huge muddy plumes of water fill our lagoons. Our island’s reefs are under great threat of sedimentation. Unregulated deforestation and development, illegal road building (especially during rainy season), and the rampant destruction of huge swathes of mangroves, the list of threats is endless. Only through more conscientious development will Roatan’s reefs have a fighting chance.


SEAGRASS – THE FORGOTTEN ECOSYSTEM

Friday, March 19th, 2010

To create the “turquoise water and white sand beach” image that is printed on every postcard and advertisement in the Caribbean, hotels and resorts continue to remove seagrass. In addition to extracting it from the water, hotels and businesses either bury washed up vegetation or place it in plastic bags bound for the dump. This is done to create a more aesthetically pleasing swimming environment with the belief that seagrasses harbor organisms harmful to swimmers. Seagrasses, however, are an economically and ecologically crucial marine habitat. The same seagrasses that are removed for being unsightly actually protect the white sand beaches and tropical waters that draw tourists to our island.

 People should know that waters lacking sediment and nutrients are better for coral reef health. Seagrasses reduce impacts of sewage and run-off on corals by absorbing much of the nutrients before they reach the reef zone. Seagrasses also reduce wave power, thereby consolidating sediments and minimising coastal erosion. A recent study in Mauritius found that beachside hotels that removed seagrass became the victims of their own innovation. In as little as a year, beaches had entirely disappeared due to coastal erosion. The fishing industry also benefits from the existence of seagrasses. They provide shelter for juvenile grouper, snapper, conch and lobster, and are an important food source for adult fish, helping to keep fishing sustainable.

 Coral reefs are designed to benefit from occasional natural disturbances such as hurricanes. But human degradation of Roatan’s reef and associated habitats (upon which tourism success depends) is reducing its ability to recover from such events. The potential result–ecological and economic collapse, perhaps as soon as the next major hurricane.

 While authorities fail to enforce environmental laws, developers need to take on more of a moral responsibility to ensure that their activities are not damaging the natural resources that bring people to the island.


RMP in the News: A Real Drag

Wednesday, November 4th, 2009

The Roatan Marine Park appeared in an article published in TheCrewReport.com entitled A Real Drag, Part II by Juliet Benning.

The article discusses the severe and irreperable damage caused by anchor damage, including a high-profile case that occured in the Roatan Marine Park in March 2009.

Download A Real Drag, Part II here [PDF, 840kB]