Volvox aureus

We use V. aureus: to demonstrate a unique experimental capability using Gravity Machine. This is the ability t pattern "Virtual-reality environments" for single cells and small swimming organisms. Here we show this for a vertically-patterned light-intensity gradient. As the V. auerus colony swims upwards, the experiment triggers an alternating transition in the ambient light intensity for every 2 cm change in the organism's depth (a purely arbitrary choice chosen for demonstration purposes). This gives us a unique window into the photo-response over much longer scales than has been possible earlier. Notice the small jerks in the track that appear as the colony triggers repeated transitions in the light levels (the first of these occurs at a time-stamp: 72 s).