|
Specimen
047
Closterium are a genus of single-celled algae that frequently have a distinctive crescent shape. Large, single-cell algae known as desmids, of which Closterium is the most common, have fluid-filled cavities containing tiny crystals of barium sulfate, which they scavenge from water. You can see in this video terminal vacuoles at the tips of the 'crescent' that hold tiny vibrating crystals of barium sulfate. Brownian motion causes these microscopic particles to move erratically due to the impacts of collisions with the surrounding liquid molecules in which they are suspended. The function of these barium crystals serve is a mystery to science, but one theory is that Closterium use them as gravity sensors to orientate themselves. Whatever the reason, barium is not an optional extra for these algae: desmids will not grow in the absence of barium. |