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Complete bunk.

Bermuda Natural History
Geologic History

The information for this summary is from a lecture given at BBSR by David Malmquist.

Bermuda is a volcanic sea mountain that formed from the mid-Atlantic ridge approximately 100 million years ago. Through the processes of plate tectonics and sea floor spreading, this volcano moved to the west of the mid-Atlantic ridge and became extinct. About 30 million years ago, the volcano erupted again, probably due to it floating over a hot spot in the Earth’s crust. Afterwards, the volcano became extinct again, and has remained so to this day. Bermudians do not seem to worry about an eruption anytime soon! Actually, there are two calderas, or mouths, of the volcano. There are both located under water - one is at Hamilton Harbor and the other is at Castle Harbor.

Over the millions of years, a limestone cap has formed on top of the volcanic rock. The origin of this limestone is living organisms - those that make up and live in the coral reef. There are two categories here: reef builders and reef breakers. Reef builders, which include coral and the algae that live symbiotically with them, produce a calcium carbonate skeleton. Reef breakers, such as parrotfish, come along and eat the algae that is living on the coral. In the process, they inevitably break off and ingest some of the calcium carbonate. This calcium carbonate passes through the gut of the fish and comes out as sand (lime sand, to be exact). Over time, as sea level fluctuated, this sand was pushed up onto the volcanic rock and sand dunes were formed. Through the processes of dissolution and cementation, this sand became rock (limestone). Dissolution and cementation involve acidic rain (all rain is naturally, slightly acidic because of dissolved carbon dioxide from the air) falling on the sand and dissolving it. When the water evaporates, limestone is formed.

To summarize, Bermuda is an underwater volcano with a limestone cap. When one looks at the natural terrain today, only the limestone cap is visible. Of course, one can also see plenty of sand (yes, it is pink!) and also some rich, red soil known as terra rossa soil. You may be wondering why the sand is pink. It is because of organisms called forams, whose shells are pink and are mixed in with the sand formed by the reef builders and breakers.You may also be wondering where the terra rossa soil came from. Believe it or not, scientists believe that much of it is atmospheric dust that has been blown to Bermuda from the Sahara desert (by hurricanes in the summer) and from the Great Plains of North America (by westerly winds in the winter)! There is also evidence (the presence of a lot of phosphate) that bird guano has contributed to the formation of terra rossa soil. Another interesting geologic phenomenon on Bermuda is the existence of many caves. These formed when acidic rain dissolved some of the limestone as it percolated dwon and then out to sea. This would lead to there being a long tunnel. Then, the tunnel ceiling collapsed in some places, but not in others, forming caves.

Source:
Bermuda Biological Station for Research, Inc.

The Bermuda Biological Station for Research (BBSR) was founded in 1903. It is located on St. George’s Island in Bermuda. The BBSR has three main functions: to conduct oceanographic research, to educate others about its work, and to provide facilities for visitors (scientists, teachers, students). The facilities include laboratories, vessels, lecture and meeting rooms, accomodations, transportation, a library with computers, and knowledgable and friendly support staff.

Scientists Uncover a Dramatic Rise in Sea Level and Its Broad Ramifications

Feb. 9, 2009

Scientists have found proof in Bermuda that the planet’s sea level was once more than 21 meters (70 feet) higher about 400,000 years ago than it is now. Their findings were published in the journal Quaternary Science Reviews Wednesday, Feb. 4.

Storrs Olson, research zoologist at the Smithsonian’s National Museum of Natural History, and geologist Paul Hearty of the Bald Head Island Conservancy discovered sedimentary and fossil evidence in the walls of a limestone quarry in Bermuda that documents a rise in sea level during an interglacial period of the Middle Pleistocene in excess of 21 meters above its current level. Hearty and colleagues had published preliminary evidence of such a sea-level rise nearly a decade ago, which was met with skepticism among geologists. This marine fossil evidence now provides unequivocal evidence of the timing and extent of this event.

The nature of the sediments and fossil accumulation found by Olson and Hearty was not compatible with the deposits left by a tsunami but rather with the gradual, yet relatively rapid, increase in the volume of the planet’s ocean caused by melting ice sheets.

A rise in sea level to such a height would have ramifications well beyond geology and climate modeling. For the organisms of coastal areas, and particularly for low islands and archipelagos, such a rise would have been catastrophic. The Florida peninsula, for example, would have been reduced to a relatively small archipelago along the higher parts of its central ridge.

“We have only to look at Bermuda to begin to assess the impact for terrestrial organisms or seabirds dependant on dry land for nesting sites,” said Olson. “This group of islands in the Atlantic was so compromised as a nesting site for seabirds that at least one species of shearwater became extinct as well as the short-tailed albatross, marking the end of all resident albatrosses in the North Atlantic.”

Determining the timing and extent of this global rise in sea level is not only important for interpreting the influence that it may have had on biogeographical patterns and extinctions of organisms on islands and low-lying continental coastal areas, it is also critical for anticipating the possible effects of future climate change. This particular interglacial period is considered by some scientists to be a suitable comparison to our current interglacial period. With future carbon dioxide levels possibly rising higher than any time in the past million years, it is important to consider the potential effects on polar ice sheets.

Biogeographers, conservationists and many others in the biological sciences must take these findings into consideration, Olson urged. “These findings are incredibly important and have major relevance because of their potential predictive value since this sea-level rise took place during the interglacial period most similar to the present one now in progress. It thus becomes essential that the full extent and duration of this event be more widely recognized and acknowledged.”

http://newsdesk.si.edu/releases/nmnh_sea_level_rise.htm