A water sample taken by Heal the Bay scientists off the Santa Monica Pier this week confirmed what Malibu’s more avid beachgoers may already know: Local beaches are experiencing a red tide. The phenomenon causes normal blue-gray water to take on a rusty, brownish pigment due to an overabundance of algae. While not all red tides are harmful, about a third of the algae species causing red tides can cause adverse health affects, according to a news brief on Heal the Bay’s website.
During such toxic red tides, mussels, clams and other shellfish that filter algae for food can safely ingest the toxins. However, humans who eat the shellfish can suffer nausea/vomiting, diarrhea tingling or numbness. That risk is the reason for the annual mussel harvesting quarantine along the length of the California coast that lasts from May 1 to Oct. 31.
Some people also believe that coming into contact with water or breathing sea spray affected by red tide can cause eye irritations, skin discomfort and sore throats. Heal the Bay’s website urges people to be safe but to check out the unique conditions along the coast.
One pleasant side effect of red tides is increased bioluminescence due to the presence in the water of exponentially greater numbers of dinoflagellates, micro organisms that help make up algae. The dinoflagellates can be seen lighting up the surface of the water at night. The Heal the Bay website includes this link to video of surfers catching neon waves during a red tide: http://www.theatlantic.com/video/archive/2011/10/surfers-catch-stunning-bioluminescent-waves/246138/.
Photo courtesy of NOAA.