Posted by admin | 12.20.2011 | Turtle Talk

Tide Turning on Turtles

Sea turtles need to tread carefully near Lee and Collier counties as a harmful algal bloom (HAB for short) is creating some dangerous conditions in a 40 mile stretch of water. A dinoflagellate population of Karenia brevis has recently exploded off Florida’s Gulf Coast, and may already be responsible for at least one Kemp’s ridley death.

HABs, previously referred to as red tides, are a centuries old phenomenon that may deplete oxygen levels in the water and produce powerful toxins that can result in death. They occur when naturally occurring phytoplankton experience rapid population growth and their numbers bloom beyond safe levels. Sometimes they even stain the water a reddish color, hence the previous title, though they can actually be many different colors.

Scientists are using the outbreak to see how tagged turtles react during an HAB. Most remained in the Pine Island Sound, but a Kemp’s ridley named Dorothy that moved into the bloom is now presumed dead. Another 10 turtles have died in southwest Florida since the outbreak, but their cause of death is still being determined. This particular algae releases brevetoxins that cause injury when ingested or inhaled, and turtles are particularly susceptible,  requiring about 50 days to clear the toxins from their system. They also run the risk of reabsorbing them through their intestines. By comparison, birds are able to clear the same toxin in about 10 days.

Further research hopes to yield potential medications that can bind to the toxin and result in its expulsion, providing much needed relief for turtles. K. brevis is not all bad, however. Scientists believe that the dinoflagellate produces a compound that could be used to treat cystic fibrosis and other respiratory diseases, providing further proof of the important role that oceans play in our lives.