An Array Of Photosynthetic Plankton Collected From The California Coast By A Colleague (thanks Greg!) 

An array of photosynthetic plankton collected from the California coast by a colleague (thanks Greg!) 

The first two are diatoms- an unknown species and Biddulphia (mobilienisis?). I’m not too certain what those last two are, but that’s the beauty of microscopy. No matter how much you’ve seen, you’ll eventually find something completely new! 

…no but seriously if anyone can help me identify those that would be great :D

The various spines and needles help keep the plankton buoyant and may possibly deter grazing from other plankton looking for a meal. I say may because some copepods actually prefer spiny diatoms over spine-less variants of the same species. To the copepod, the spines make the diatom seem bigger and thus more appealing as food (source). I guess that makes these diatoms the equivalent of bags of chips filled with mostly air.