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Rarities in the reefs

Rarities in the reefs

Near the beaches of Maceió: the unusually colored blue Plakina coerulea sponge

EDUARDO HAJDUNear the beaches of Maceió: the unusually colored blue Plakina coerulea spongeEDUARDO HAJDU

In scouring the crusts and crevices of coral reefs on popular beaches near Maceió, capital of the state of Alagoas, a group of researchers from the Federal University of Alagoas (Ufal) and the National Museum of the Federal University of Rio de Janeiro (UFRJ) have identified three new species of marine sponges. The species were described in an article published in the August 2013 issue of the Journal of Natural History by Victor Cedro and Mônica Correia of UFAL, and Eduardo Hajdu of UFRJ. One of the new species is the Plakina coerulea, which is blue, a color that is very rare among sponges, which tend to be red or yellow. The other two were Rhabderemia meirimensis and Mycale rubra. The finding is surprising because the region has been searched for decades and suffers daily from the impact of contact with the local population and tourists, who damage the reefs. Sponges are among the oldest multicellular organisms and prefer to grow in the darker, deepest areas of reefs, where they face no competition from algae and corals, which grow better in brighter regions. Of the species identified, only one individual was found of two of the species and only two were found of the third. In general, each specimen was only a few centimeters in size. Hajdu explains that the sponges, in addition to helping shape recesses in reefs that serve as shelter for other organisms, assist in controlling the population of bacteria, which they eat by filtering seawater. “They filter a volume of water 10,000 times greater than their size every day,” says Hajdu. “There must be other rare species living near cities that we’ll never discover if there is no change in attitude towards conservation of these environments.”