Bermuda

Abstract

Bermuda has a history of development characterized by poor wastewater and sewage treatment systems. Furthermore, Bermuda’s high population density and poor waste management increases the risk of pollution to marine ecosystems. Increased pollution poses a threat to inshore coral reefs by creating environmental stress which increases vulnerability to disease. One such species that is threatened by pollution is the purple sea fan (Gorgonia ventalina), which is common throughout inshore reefs of Bermuda. Aspergillosis is a fungal disease that commonly infects sea fans, and was the cause of a major epizootic among sea fans in the Caribbean in the late 1990s. I predicted that sea fans in dense colonies and in locations of high environmental stress would have a higher incidence of Aspergillosis. The number of non-diseased sea fan colonies, diseased sea fan colonies, and sea fan colonies partially or entirely lacking zooxanthellae was collected from three locations in Bermuda using the band transect method. Water samples were also collected to indicate pollution inputs. Results did not support my predictions, likely due to small sample sizes, lack of pollution and low incidence of Aspergillosis. Above: Aerial photo of Bermuda, BIOS, www.bios-mep.info.

Background Information

Bermuda is a group of semi-tropical islands located in the Atlantic Ocean, 600 miles southeast of Cape Hatteras and 800 miles south of Nova Scotia (1, 2). Bermuda consists of seven main islands and several other smaller islands which cover 21 square miles, with a resident population of about 64,000 (3).

History and Development

The islands of Bermuda formed from a volcanic eruption approximately 110 million years ago (1, 2). Bermuda’s islands are called ridge islands, due to the fact that the vocanic eruption that formed the islands developed out of the Mid Atlantic Ridge at the junction of two tectonic plates. Since the first eruption of Mount Bermuda the islands have been moving away from the ridge, traveling 500 miles in the last 30 million years (2). During this time the volcano subsided below the surface, and fringe reefs developed into barrier reefs which eventually formed a coral atoll (1, 2). The islands are the only section of the atoll that is above sea level; the other sections now form rim reefs encompassing a large lagoon (1). Below: Atoll formation and Bermuda's reefs, www.coexploration.org.
 
The island of Bermuda was first colonized in the 1600s by the British, becoming a self-governing colony in 1620. The island’s abundant cedar trees were the foundation of the economy, used for shipbuilding and exchanged in trade (3). Colonization is considered to have had deleterious effects on the natural ecology and landscape of Bermuda. Early colonists introduced rats, mice, exotic seeds, disease, and domesticated animals. Bermuda and the species living there had been isolated for thousands of years, with very low levels of competition between native species and lack of large predatory animals. Therefore, these new species introductions were detrimental; native species had little defense and competitive mechanisms to protect themselves from the threats of introduced species. Tree species such as the Bermuda Cedar, Yellow Wood, and Palmetto were exploited for a variety of uses from furniture to flavoring alcoholic drinks. Accidentally introduced species have also had detrimental effects, such as scale insects which carried tree blights that decimated 99 percent of the cedar population on the island. At times species were intentionally introduced as a control mechanism for the accidentally introduced species. Most often the species that were introduced to control the pests had unintentional effects themselves. Due to colonization and the devastating effects of introduced species, only five percent of the plant species currently on the island are native or endemic, while 99.3 percent of the current marine flora and fauna is native or endemic (2).