A stunning discovery An unknown coral reef over a thousand kilometres long (and 9300 square km in ar

A stunning discoveryAn unknown coral reef over a thousand kilometres long (and 9300 square km in area) has emerged from obscurity in a place where according to the textbooks it should not be, hiding beneath the large cloud of swirling sediment flowing around the delta of the globe’s largest river: the Amazon. Scientists have expressed astonishment at the anomalous find, something us hard bitten sceptics rarely allow ourselves.Normally rivers create gaps in reefs running parallel to coasts, due to their freshwater and mineral content altering the salinity and acidity of the ocean. Corals also usually thrive in clear tropical water where light can shine through so that their symbiotic algae can photosynthesise, and the kind of turbidity brought by the sediment plume was thought to preclude coral growth (by blocking light and dropping sediment atop the growing corals), so no one ever looked for them in such a place (until now, just as they are under threat from the newly sold and developed oil exploration and production blocks, some of which suit right atop the previously unknown structure).The colonies thrive because there is a separation between salty and fresh water, and they live below the seasonally shifting line between the two masses of water, which mix slowly. While not as rich an ecosystem than more familiar tropical reefs, many species of exotic sponge (the largest the weight of a baby elephant), sea urchins, lobsters and fish were found living in the coralline cities. The wonder of it all is that such a vast ecosystem remained hidden in plain sight, until its fortuitous discovery by an oceanographic research team who were using the RV Atlantis to see how the sediment plume as affecting CO2 absorption in the ocean, and following up a few exotic reef fish dredged out of the area and reported in a paper from 1977 on behalf of a Brazilian colleague. Boy did they get a shock when the dredgers came up. Their discovery is the northernmost reef in Brazil.Further research suggests that the ecosystem is quite diverse, varying from place to place according to the local light and water conditions and seasonal variation over the year. Some areas in the southern section are only covered by the plume some months of the year, and hence can photosynthesise more and are more diverse and colourful due to the greater primary production, while the less diverse muddier, low light and oxygen poor northern reaches are dominated by sponges. The very existence of a low light, low oxygen coral reef is as big a game changer as the low diversity deep ocean reefs discovered some years past.As you all know, reef environments are the rainforests of the sea, and they are all dying due to global warming and a process called bleaching, just this week it was announced that 93 % of the Great Barrier Reef was bleached in what is turning into the worst event of this kind on record. See our past posts on the coming end of reefs at: http://bit.ly/1MJqONe, http://bit.ly/1EhnfaO, http://bit.ly/1Vr7lap and http://bit.ly/23xFbMY.LozImage credit: NASAhttp://bit.ly/23OyYizhttp://bit.ly/1WLkBWUhttp://bit.ly/1T4blrjhttp://bit.ly/1VHn1XAhttp://bit.ly/1XIcPuYOriginal paper, paywall access: http://bit.ly/1qGWCvm -- source link

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