Researchers view swimming tactics of tiny aquatic...( By applying state-of-the-art hologra...)

By applying state-of-the-art holographic microscopy to a major marine biology challenge, researchers from two Baltimore institutions have identified the swimming and attack patterns of two tiny but deadly microbes linked to fish kills in the Chesapeake Bay and other waterways.

The study, reported in the October 22-26 online Early Edition of Proceedings of the National Academy of Sciences, focused on the aquatic hunting tactics of two single-celled creatures classified as dinoflagellates. These two-tailed microbes feed on even smaller prey that are attracted to the algal blooms caused by water pollution. Scientists are concerned because these dinoflagellates produce toxins that can kill large numbers of fish, but studying the predators under a conventional microscope is difficult because the tiny animals can quickly swim out of the microscopes shallow field of focus.

In the journal article, the researchers from The Johns Hopkins University and the University of Maryland Biotechnology Institute reported that they had solved this depth-of-field problem through a technique called digital holographic microscopy, which captured three-dimensional images of the troublesome microbes. The process also enabled the team to identify the tiny predators distinctly different swimming and hunting tactics.

Its like being at NASCAR with a magical pair of binoculars that can keep the entire field of view in focus, so cars both near and far are equally sharp and discernible, said Robert Belas, a professor of microbiology at UMBIs Center of Marine Biotechnology. Digital holographic microscopy offers dramatic increases in depth-of-field.

This is a breakthrough technology in quantifying dinoflagellate behavior, said Allen R. Place, a professor of biochemistry at UMBIs Center of Marine Biotechnology. We can now begin to look for answers that were previously unattainable.

Chesapeake Bay fish kills caused by dinoflagellates are considered
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