Diatoms are a major group of typically unicellular algae, and are one of the most common varieties of phytoplankton. Unique to diatoms, their cells are encased in a cell wall of silica (silicon dioxide), which is responsible for their crystalline appearance. Diatoms are autotrophic, meaning they derive their nutrition from their surroundings by means of photosynthesis or chemosynthesis. This places them in the role of producers in the food chain.

Eukaryota > Chromalveolata > Heterokontophyta > Bacillariophyceae

Padina pavonica

Commonly known as the Peacocks tail, Padina pavonica is a species of brown alga that is Atlantic Ocean and the Mediterranean Sea. P. pavonica usually inhabits rock pools and stones, but can also be seen in depths of around 60m (200 ft). P. pavonica owes its white coloration to a deposit of calcium carbonate.


Chromalveolata-Heterokontophyta-Phaeophyceae-Dictyotales-Dictyotaceae-Padina-P. pavonica

Image: Matthieu Sontag

Sea Palm (Postelsia palmaeformis)

Also known as palm seaweed P.palmaeformis is a species of kelp that is widespread along the western coast of North America. Although it may look like a plant P.palmaeformis is actually a large species of brown algae and is a protist. Sea palms are one of few species of algae that can survive and remain erect outside of water, and it spends most of its life exposed to air. Sea palms inhabit the middle to upper intertidal zones in areas with very high wave activity.



Image: Eric in SF


Subclass: Hypotrichia

…is a group of ciliate protists related to the spirotrichs. Hypotrichs are typically oval in shape and posses a rigid pellicle with cirri, Hypotrichs are fairly well represented, occurring in both freshwater an saltwater. They are fairly active feeders as well, with individuals hanging on to objects and using their cilia to obtain nutrients. 



Image(s): DHZanette