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AUSTRALIA: The Secrets of Slime |
| December 3, 2004 |
 | Research divers use 'bongo nets' to collect marine snow, which researchers believe may be a byproduct of marine biofilms.
Photo: NOAA |
Australian scientists have a new way to determine the health of a coral reef: they are studying slime.
Naturally occurring marine slimes – better known as biofilms or biological films – consist of millions of mucus-generating bacteria and algae. Biofilms grow quickly and respond rapidly to changes in ocean conditions, which can help to warn scientists if the conditions around a reef are changing for the better or for the worse. They are also an important building block in the formation of a coral reef.
"Research shows that so-called 'turf algae,' which carpet the sea bottom like mosses, have an important role in the regeneration of coral reefs," said Dr. Sven Uthicke, a biofilm expert at the Australian Institute of Marine Science (AIMS). "If water conditions are good, the turf algae are naturally replaced by coralline algae, which in turn allow new corals to grow. If water conditions are poor, then the turf algae trap a lot of sediment in a sort of thick, grungy mat which prevents corals from re-growing."
The scientists are particularly interested in determining whether biofilms are related to marine snow, a phenomenon in which tiny snow-like particles rain down on and smother coral reefs. Certain conditions can prompt the microbes that make up the biofilms to shed their slime, which in turn forms sticky, suspended clumps resembling snowflakes. But because the highest concentrations of marine snow occur near the coast, where human inputs of sediment and nutrients are greatest, scientists are unsure whether marine snow is a natural event related to biofilms or one caused by human activities on land.
"At present there are many unanswered questions, but we are optimistic that it will provide us with another way of looking at reef health in the short term," said Dr. Katharina Fabricius, an AIMS coral reef ecologist. "In particular, it can tell us a lot about the conditions needed for coral to regenerate. With more and more coral dying off through bleaching events linked to warming, this is a vital issue."
Source: Australian Institute of Marine Science
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