Physical limits on bacterial navigation in dynamic environments.

Area of Science:

• Microbiology
• Biophysics
• Environmental Science

Background:

• Bacteria navigate chemical signals in dynamic environments.
• Chemical signals often appear as localized pulses.
• Environmental factors like diffusion and mixing alter chemical landscapes.

Purpose of the Study:

• To investigate the physical limits of temporal gradient sensing in chemotactic bacteria.
• To define the conditions under which bacteria can accurately measure chemical cues.
• To explore the role of chemokinesis in enhancing bacterial chemotaxis in dynamic environments.

Main Methods:

• Mathematical modeling of bacterial temporal gradient sensing.
• Analysis of bacterial navigation within dynamic chemical landscapes.
• Framework development for partitioning bacterial populations based on proximity to chemical hotspots.

Main Results:

• Physical limits on temporal gradient sensing accuracy govern bacterial navigation.
• Bacteria can only resolve chemical gradients above noise within a predictable dynamic region around pulses.
• The boundary of this dynamic region expands with the square root of time before contracting.
• Chemokinesis may enhance chemotactic accuracy and sensitivity in dynamic environments.

Conclusions:

• Bacterial chemotaxis accuracy is fundamentally limited by physical constraints on gradient sensing.
• A dynamic region defines the 'navigable' space around chemical hotspots.
• Understanding these limits is crucial for predicting bacterial behavior in complex aquatic ecosystems.