Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Marine bacteria's mealtime dash is a swimming success

11.03.2008
Goldfish in an aquarium are able to dash after food flakes at mealtime, reaching them before they sink or are eaten by other fish. Researchers at MIT recently proved that marine bacteria, the smallest creatures in the ocean, behave in a similar fashion at mealtime, using their swimming skills to reach tiny food patches that appear randomly in the ocean blue.

The behavior of bacteria at these small scales could have global implications, possibly even impacting the oceans’ health during climate change.

Scientists in the Department of Civil and Environmental Engineering 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.

Food sources for these microorganisms come as dissolved nutrients and often appear as localized patches that, if not eaten, are rapidly dissipated by physical processes like diffusion. Foraging, then, becomes a race against time for a bacterium. A rapid response gives it a strong advantage over competitors and may allow it to take up nutrients before they undergo chemical changes. A paper scheduled to publish in the Proceedings of the National Academy of Sciences online Early Edition the week of March 10 describes the research.

“Our experiments have shown that marine bacteria are able to home in very rapidly on short-lived nutrient patches in the ocean,” said Roman Stocker, the Doherty Assistant Professor of Ocean Utilization and lead author on the paper. “This suggests that P. haloplanktis’ performance is finely tuned to the oceanic nutrient landscape. If you are a bacterium, the ocean looks like a desert to you, where food mostly comes in small patches that are rare and ephemeral. When you encounter one, you want to use it rapidly.”

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.

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.

Until 25 years ago, scientists weren’t 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 dropping out of the marine food web.

But quantifying the importance of bacteria in the microbial loop has been difficult, because creating a realistic microenvironment wasn’t possible until recently.

“You can hope to study an organism’s behavior only in the context of its environment. The habitat of a bacterium, on the other hand, is extremely small, on the order of microns to millimeters,” said Stocker. “This has made the study of microbial behavior a formidable technical challenge to date. We have been able to create realistic environmental landscapes for studying marine bacteria in the lab by using microfluidic technology.”

P. haloplanktis is a rapid swimmer, propelling itself by a single rotating flagellum in bursts of speed up to 500 body lengths per second. (The fastest land animal, the cheetah, travels at bursts of speed up to 30 body lengths per second.) During experiments, Stocker and team observed that the bacteria used their rapid motility to very effectively swim toward and follow their food sources. That directed movement in response to a chemical gradient (in this case, nutrients) is known as chemotaxis.

“It will be important to see how widespread the use of rapid chemotaxis is in the ocean,” said Stocker. “We expect this to depend on the environment; in algal blooms, for example, nutrient patches and plumes will be abundant, and speedy bacteria will be favored. Whenever this is the case, nutrients get recycled much more rapidly, making the food web more productive and potentially affecting the rates at which carbon is cycled in the ocean.”

Denise Brehm | EurekAlert!
Further information:
http://www.mit.edu

More articles from Ecology, The Environment and Conservation:

nachricht Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen

nachricht A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>