The researchers were able to prove the behavior of P. haloplanktis by recreating a microcosm of the bacterias 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 couldnt put their swimming skills to use in this race against time has generated considerable interest in the scientific community over the past decade, because theres 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.
Scientists who study Earths 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 bacterias capacity to utilize it will determine whether the oceans become a carbon sink or source during global warming.
Until 25 years ago, scientists werent really aware of the microbial loop, the processing of organic material among the smallest creatures in the ocean: bacteria, phytoplankton, nanozooplankton, viruses, etc. Now they know that the roughly 1 million bacteria per milliliter of ocean play a pivotal role in the microbial loop; by recycling that organic matter, they pass it on to larger animals and prevent it from
|Contact: Denise Brehm|
Massachusetts Institute of Technology, Department of Civil and Environmental Engineering