Marine bacteria's mealtime dash is a swimming success

Scientists in Professor Roman Stocker's research group recently proved that marine bacteria, the smallest creatures in the ocean, are able to use their swimming skills to reach tiny food patches that appear randomly in the ocean. The researchers demonstrated for the first time in lab experiments that the 2-micron-long, rod-shaped marine bacterium P. haloplanktis is able to locate and exploit nutrient patches extremely rapidly, thanks to its keen swimming abilities. The researchers were able to see the behavior of P. haloplanktis by recreating a microcosm of the bacteria's ocean environment using new technology called microfluidics. Microfluidics consists of patterns of minute channels engraved in a clear rubbery material and sealed with a glass slide. The researchers injected bacteria and nutrients into the microchannels at specific locations and, using video-microscopy, recorded the bacteria as they foraged on two simulated food sources: a lysing algal cell that creates a sudden explosion of dissolved nutrients, and the small nutrient plume trailing behind particles that sink in the ocean.

Roman Stocker's Research Group

"Rapid Chemotactic Response Enables Marine Bacteria to Exploit Ephemeral Microscale Nutrient Patches," Assistant Professor Roman Stocker, Justin Seymour, former graduate student Dana Hunt and Associate Professor Martin Polz all of MIT, and Assistant Professor Azadeh Samadani of Brandeis University. Proceedings of the National Academy of Sciences online Early Edition, March 10, 2008.