August 26, 2010

Barrel Sponges Now Dominant Life Form In Florida Keys

Xestospongia muta, better known as the giant barrel sponge, is now the most dominant life form in the coral reefs of the Caribbean and the Florida Keys, according researchers from the University of North Carolina (UNC) Wilmington.

Working at the Aquarius Reef Base near Key Largo, Florida from August 17 through August 26, UNC Wilmington professor of biology and marine biology Dr. Joseph Pawlik and professor of biology and marine biology Dr. Christopher Finelli have been studying the Caribbean barrel sponges, attempting to gather data on their mortality rate, reproductive habits, growth and age.

According to a Wednesday article by Reuters reporter Jane Sutton, Xestospongia muta won "a recent battle for dominance among corals, seaweed and sponges" in the region. That, according to what the researchers told Sutton, is "a good thing"¦ because the sponges filter the water and provide a habitat for valued fish species."

Furthermore, according to information posted to the UNC Wilmington "Sponges on Florida Coral Reefs: Demographics and Impacts on Water Quality" website, the hollow, multi-hued barrel sponges are vitally important "to habitat complexity and reef health" and "do not have calcified skeletons, and are less likely to be affected by ocean acidification due to global climate change."

"If you can't have corals, better that you should have sponges than macroalgaes," Pawlik told Sutton on Wednesday. "And right now it appears the sponges are doing OK," as their population has grown approximately 40-percent over the past decade, he added.

Pawlik and Finelli are also monitoring the area to see if the sponges are negatively affected by the oil spill in the Gulf of Mexico that started back in April. On the mission's official website "critically important for understanding future effects" of the Deepwater Horizon petroleum spill on Xestospongia muta and other marine life forms in the area, including corals and fishes.

The Aquarius Reef Base is a facility located less than four miles offshore, and is part of the Florida Keys National Marine Sanctuary. It is owned by the National Oceanic and Atmospheric Association (NOAA), and is operated by UNC Wilmington. Scientists from the university will return to the laboratory in September for a mission yet to be identified.


Image Caption: Large barrel sponge dying from "orange band disease." 50' depth, Conch Reef. Credit: C. Finelli, UNCW


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