Arriving on Longboat Key late last week, we were surprised and alarmed to find mounds of white filaments on the beach. Initially concerned that they might be plastic debris, I examined one of the strands and found that it was easily pulled apart, more likely vegetative than man-made.
Having never encountered this material in fourteen years of wandering Longboat's beaches, I contacted the Mote Aquarium. They explained that these white, straw-like filaments wash up on the beaches every few years and are thought to be bleached "manatee grass;" since root material is not attached, marine scientists believe that a large amount of the grass is broken off by a storm and, under the right current pattern, is kept floating at sea and bleached by the sun before washing ashore. A similar event occurred on beaches from Captiva to Naples in 2009, prompting investigation and leading to the above theory.
In fact, the specific cause for the irregular appearance of bleached sea grass on barrier islands remains a mystery. I was just happy to learn that it is a natural event and not another sign of human impact on marine ecosystems. My thanks to personnel at Mote Aquarium for helping to clarify this issue.
