Algae

Anabaena has a pig pen odor and signals poor water quality. It is toxic to both animals and humans and has been associated with skin rashes.

Volvox is a colony of 500 or more cells. It has a fishy odor and two flagella that are produced by daughter cells.

Staurastrum has a grassy odor, as well as spiked projectiles that help it float.

One of the things I've learned about algae this week is that it can be used to determine water quality. For example, clean water has a low population of algae and high diversity, whereas heavily polluted water has a high population of water with low diversity. Specific types of algae can provide clues on water quality as well. Batrachospermum, for example, lives in cold water with low levels of organic material and is an indicator of clean water.