Under certain conditions, <a href="https://en.wikipedia.org/wiki/Emiliania_huxleyi" class="extiw" title="en:Emiliania huxleyi">en:Emiliania huxleyi</a> can form massive blooms which can be detected by satellite remote sensing. What looks like white clouds in the water, is in fact the reflected light from billions of coccoliths floating in the water-column.<p>
<a href="https://en.wikipedia.org/wiki/Landsat" class="extiw" title="en:Landsat">en:Landsat</a> image from 24th July <a href="https://en.wikipedia.org/wiki/1999" class="extiw" title="en:1999">en:1999</a>, courtesy of Steve Groom, <a href="https://en.wikipedia.org/wiki/NEODAAS,_Plymouth_Marine_Laboratory" class="extiw" title="en:NEODAAS, Plymouth Marine Laboratory">en:NEODAAS, Plymouth Marine Laboratory</a>. This bloom attracted considerable coverage in the <a href="https://en.wikipedia.org/wiki/United_Kingdom" class="extiw" title="en:United Kingdom">UK</a> media.</p>
USGS, image courtesy of Steve Groom
1999-07-24