"It's important to be able to directly look at an environment in order to understand its ecology," Stocker said. "We can now visualize the behavior of marine microorganisms much like ecologists have done with macro-organisms for a long time."
To do this, the team recreated a microcosm of the ocean environment using a microfluidic device about the size of a flash drive with minuscule channels engraved in a clear rubbery material. The scientists injected DMSP into the channel in a way that mimics the bursting of an algal cell after viral infection a common event in the ocean then, using a camera attached to a microscope, they recorded whether and how microbes swam towards the chemical.
The researchers found that some marine microbes, including bacteria, are attracted to DMSP because they feed on it, whereas others are drawn to the chemical because it signals the presence of prey. This challenges previous theories that this chemical might be a deterrent against predators.
"Our observations clearly show that, for some plankton, DMSP acts as an attractant towards prey rather than a deterrent," said Sim, an expert on the role of DMSP in the sulfur cycle, "By simulating the microscale patches of the chemical cue and directly monitoring the swimming responses of the predators towards these patches, we get a much more accurate perception of these important ecological interactions than can be obtained from traditional bulk approaches."
"These scientists have used impressive technology to study interactions between organisms and their chemical environment at the scales they actually take place," said David Garrison, director of the National Science Foundation (NSF)'s biological oceanography program. "The research will give us new insights on the workings of microbial assemblages in nature."
The research also indicates that marine microorganisms have at l
|Contact: Jennifer Hirsch|
Massachusetts Institute of Technology