Marine bacteria's mealtime dash is a swimming success

Using microfluidics technology and videomicroscopy, researchers at MIT's Department of Civil and Environmental Engineering demonstrated that marine bacteria are able to make use of their swimming abilities to reach nutrient... Click here for more information.

Co-authors on the paper are postdoctoral associate Justin Seymour, graduate student Dana Hunt and Associate Professor Martin Polz all of MIT, and Assistant Professor Azadeh Samadani of Brandeis University.

The researchers were able to prove 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.

The question of whether the bacteria could or couldn’t put their swimming skills to use in this race against time has generated considerable interest in the scientific community over the past decade, because there’s a great deal riding on P. haloplanktis’ and their relatives’ ability to reach these nutrients and recycle them for other animals in the food web.

This image shows P. haloplanktis aggregating in a plume of nutrients in a microfluidics device that creates a microcosm of the bacteria' natural home in the ocean. Click here for more information.

Scientists who study Earth’s carbon cycle know that accounting for all the organic matter in the marine food web is critical, including the matter that exists in these tiny, discrete nutrient patches bacteria feed on. In fact, the carbon in those patches is so important that some scientists believe marine bacteria’s capacity to utilize it will determine whether the oceans become a carbon sink or source during global warming.