Controlling blooming algae

Milena Bruno and colleagues in the Department of Environment and Primary Prevention, at the Istituto Superiore di Sanità, in Rome, Italy, point out that bodies of water across the globe have undergone increasing eutrophication over the last four decades. Changing nutrient and pollution levels due to the release of human waste, agricultural run-off, fish farming, and changing global climatic conditions has led to an increase in algal blooms. Inadvertent transportation of dormant algal cysts in ship ballasts has also contributed to them becoming more widespread.

“Algal blooms, and harmful algal blooms in particular, have multiplied enormously throughout the world over the last 40 years,” says Bruno, “in parallel with human population growth and industrialization.” The researchers add that extreme cases are seen in North America, where incidence increased from 200 to 700 per year from the 1970s to the 1990s, in Japan, and in Europe.

The team has suggested a range of new control strategies, including a sterilization program for ensuring shipping ballast water does not act as a transportation system for algae. They also point to success in treating algal blooms using clay particles to kill the algal cells.

The researchers also suggest that remote sensing and satellite imaging technology could be used to monitor algal growth around aquaculture areas where corralled fish and shellfish are grown, particularly in the Far East. Seafood contaminated with algal toxins can lead to severe and potentially lethal outbreaks of food poisoning.

They add that these and other strategies should be operated alongside a medical information network that can track health problems, such as dermatitis in swimmers and food poisoning, related to algal blooms.

“Bearing in mind the problems caused by the presence of algal blooms and the difficulties involved in eliminating them, it is obvious that adequate measures of prevention and the proper management of the ecology along coasts and in the open sea are of prime importance,” Bruno says.