Soap-like foam produced by red tide algae caused American seabird deaths in 2007

February 21st, 2009 - 2:59 pm ICT by ANI  

Washington, Feb 21 (ANI): Intensive investigation by scientists has determined that a massive red tide bloom of marine algae had produced a foamy soap-like substance that stripped the natural waterproofing from the feathers of seabirds in the US, causing them to die in large numbers.

This massive die-off happened in late 2007, when hundreds of dead and stranded seabirds washed up on the shores of Monterey Bay, their feathers saturated with water and coated with an unknown substance.

The problems we traditionally associate with harmful algal blooms are caused by toxins produced by the algae. In this case, it was a surfactant that removed the water-repellent properties of the feathers, said Raphael Kudela, professor of ocean sciences at the University of California, Santa Cruz.

Although this red tide bloom was nontoxic, it was very harmful to the affected birds, which included grebes, loons, northern fulmars, and surf scoters.

Live birds found stranded on beaches around Monterey Bay were starving and severely hypothermic, having lost the insulation normally provided by their waterproof plumage.

A total of 550 birds were stranded alive and 207 were found dead during this event.

There were a lot of questions at the time about whether the stranding was related to those events, and we were able to eliminate those possibilities, Kudela said.

The dominant species in the red tide was a type of dinoflagellate known by the scientific name Akashiwo sanguinea, which has caused red tides in the past without harmful effects on wildlife.

Kudela said that the problems in 2007 resulted from the unusual combination of a large red tide late in the year, when large numbers of migrating birds had arrived in the area, plus big waves that churned up the water.

An algal protein produced the slimy foam that fouled the birds feathers. Its effects were similar to those of soap and other surfactants that are used in detergents to dissolve grease.

Wave action contributed to the problem by breaking up the cells of dying algae and churning the dissolved protein into the thick foam that was seen along the shoreline and floating on the surface of the water.

We grew the algae in the lab, and when we shook it up it produced the same foam, Kudela said. The waves act like a blender, churning up the cells and the protein, he added.

Although 2007 was the first time we saw an impact on birds, the conditions are there for the same thing to happen the next time we have that combination of red tide, birds, and big storm waves, he said. (ANI)

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