URI study of ‘green tides’ aims to reduce impact of summertime algae blooms

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KINGSTON, R.I. – July 16, 2008 – Seaweed covered beaches and algae filled waterways are an increasing problem around Narragansett Bay during the summer months, but not enough is known about the size, duration and effects of these “green tides” to predict and manage them effectively.

So University of Rhode Island seaweed ecologist Carol Thornber and Roger Williams University algae systematist Brian Wysor are trying to provide some answers.

With the help of a Collaborative Research Grant from the Rhode Island Science and Technology Advisory Council, they are spending the summer identifying the algae species involved, studying the most frequently effected sites, and proposing management strategies designed to reduce its impact.

“Green tides are prolific blooms of macroscopic green algae – seaweed – that can lead to environmental degradation and negatively effect fishing and other recreational uses of the bay,” said Thornber, URI assistant professor of biological sciences. “It’s extremely difficult to tell some of the different species apart, even under a microscope, which is a huge stumbling block to trying to control it.”

Thornber has been conducting monthly surveys of algae at several locations around Greenwich Bay for three years. In addition to collecting representative specimens of algae, she is assessing the total mass of algae at each site and conducting detailed field studies to better understand the physical characteristics of the sites where green tides occur most often.

“In some places we always seem to find huge masses of algae, but in most places it’s patchy and variable,” Thornber said. “We hope this analysis will help us find long-term trends so we can make predictions about when and where green tides will occur in the future.”

The identity and geographic origin of the specimens that Thornber collects are being evaluated by Wysor using a newly developed DNA barcode system that is fast and cost effective.

“A DNA barcode is a standardized region in a gene that can serve as a species’ fingerprint and allow for comparison across diverse groups of organisms,” explained Wysor. “It will also facilitate studies of green tides elsewhere around the world.”

According to the researchers, the results of their project will help to identify solutions for managing green tide events. Some green tide species absorb heavy metals, while others may be a source of new pharmaceuticals or human nutritional supplements.

“While it can be a nuisance, we shouldn’t think of algae as always being a problem,” noted Thornber. “It provides important habitat for juvenile fish, it absorbs nitrogen, and it provides food for a great many marine creatures. Hopefully by the end of our project, we’ll know of even more beneficial uses for it.”