Seeing Red

2017-11-22 00:38:02


Harmful algal blooms (HABs) occur when large amounts of algae propagate out of control while creating toxic effects on people, fish, shellfish, marine mammals, and birds. Though rare, human illnesses caused by HABs can be debilitating or fatal.
The term 'red tide’ is often used to describe this widespread phenomenon, however, scientists prefer the term harmful algal bloom. The growth of algae often turns the water red or brown during the day, giving it the name sake “red tide”. At night, the same algae can produce an illuminating aqua effect on the water turning the waves into something out of James Cameron’s Avatar. Practically every summer along Florida’s Gulf Coast, one of the most well-known and documented bloom occurs, yet HABs have been reported in every state. Florida, Southern California, and the Great Lakes are impacted annually by these blooms that cause fish die-offs, shellfish poisoning, and respiratory problems in humans and pets. “HABs are a national concern because they affect not only the health of people and marine ecosystems, but also the 'health' of local and regional economies,” according to NOAA’s website.
Scientists have been studying HABs for years, trying to identify particular triggers for the mystery manifestations. According to a recent article on Science Daily, the Scripps Institution of Oceanography at the University of California San Diego’s scientist George Sugihara and his colleagues may have finally cracked the code to what causes “red tides” to form.
Physical aspects of the Southern California coast were combined with nutrient concentrations and chlorophylla data (the primary pigment in algae), and then fed into Sugihara's equation-free models, known as empirical dynamic modeling (EDM). Patterns were finally identified that may be useful in predicting red tide incidences. Its findings suggest that HABs may not be as random as originally thought.
Red tides were a mystery for so many years because we were looking at the ecosystem as if it was in equilibrium and unchanging and therefore could be studied a piece at a time," said Sugihara, the McQuown Chair Distinguished Professor of Natural Science and a senior author on the study. "It was a mystery only because we were looking at it the wrong way. Looking for things that simply 'correlate' with red tides will fail." The modeling method utilized in this study is based on the idea that an ecosystem is always changing. Therefore, for this method to be effective we must look at this dynamic ecosystem as a whole rather than numerous pieces. Sugihara identified the mechanisms causing red tides using 30 years of archived field data.
"Even with vast improvements in 'ecosystem forecasting' over the past few decades, it remains a major challenge for scientists," said Alan Tessier, deputy director of the National Science Foundation's (NSF) Division of Environmental Biology. "This research shows that the challenge is being overcome using innovative techniques that offer us information such as how to predict red tides. That's important for knowing when to close fisheries and swimming areas, and for the health of residents who live along affected waters."
"The approach allowed us to find factors that come together as a perfect storm to produce a red tide," said Sugihara. "These factors include having a stable water column and low nutrient levels in surface waters."
With further studies and the addition of real-time observations, Sugihara and his team believe that HABs could be predicted as part of an early-warning system. This system would be extremely useful for public health and economic reactions to fish/shellfish die-offs prior to a bloom. Could preventative measures be in the near future? Only time, and science, will tell.
More information on “red tides” and a link to the study: John A McGowan, Ethan R Deyle, Hao Ye, Melissa L Carter, Charles T Perretti, Kerri D Seger, Alain de Verneil, George Sugihara.
Predicting Coastal Algal Blooms in Southern California.
Ecology, 2017; DOI: 10.1002/ecy.1804 University of California - San Diego. "Red tides can be predicted, new study shows: Study paves way for possible early-warning system to forecast red tides." ScienceDaily. ScienceDaily, 13 March 2017. .