A 3,600-square mile coral reef ecosystem has been discovered beneath the murky waters of the Amazon river’s mouth and is now known as one of the greatest reef systems in the world! This 600-mile-long reef stretches along the coast of French Guiana and northern Brazil and was discovered by a team of Brazilian scientists working alongside a Greenpeace research vessel, the “Esperenza”. This reef has slowly been establishing itself beneath the murky waters of the Amazon delta, waiting to be discovered.

Scientists first hinted at the presence of this reef back in the 70’s when a fishing vessel caught coral reef fish species at the mouth of the Amazon river, something not typically expected in such an area due to the colossal amount of sediment carried downstream by the river. Furthermore, large rivers typically host unfavourable conditions for coral reef survival, due to the salinity and pH levels. Fabiano Thompson from the University of Rio de Janeiro stated that they discovered a reef “where the textbooks said that there shouldn’t be one present”. The reef itself was initially discovered in 2012 when a team of Brazilian scientists took several small dredged samples of the ocean floor; this revealed an array of sponges fish and other crustaceans. Following this discovery, a manned submarine collected the first images of the reef at depths of between 30 and 120 metres. Performing such a task proved extremely difficult due to the rough seas and thick ‘plume layer’ that covers the top surface of the delta with suspended sediment.

Only 5% of the ecosystem is said to have been mapped so far – much more is yet to be discovered with new a variety of new species expected. Further research is planned to determine how these communities function with a severe lack of light. Typically, coral reef systems utilise photosynthesis as a basic form of energy production but a new hypothesis has been proposed – Chemosynthesis. In its simplest form, this process converts nutrients and carbon-containing molecules into usable forms of energy. The microorganisms which govern this production are usually found deep in ocean trenches, not in shallow waters on the continental shelf!

A report published in 2016 indicates that the coral reef ecosystem is healthy, once again not expected given the recent decline in coral expanses because of bleaching, however this ecosystem seemingly resists the anthropogenic impacts. Scientists are now planning on monitoring the expanse of the new-found coral reef to determine how it continues to survive against increasingly unfavourable conditions. One cause for concern is that there has been recent oil exploration in the surrounding areas; in total there are 95 wells, all of which have not been found to be economically viable for gas and oil extraction. Nevertheless, oil companies such as BP and Total are still searching for potential fossil fuel deposits, if they obtain authorisation from the Brazilian government then there is the risk for further potential oil spills and water contamination. This could spell the end of the Amazon reef system before we even manage to fully discover it.

James Deed

(Image courtesy of The Guardian)