Oxygen and Oil
(Adapted from contributions by Dave Hiebert, and Neal Maine, 1988)

MICRO-ALGAE: Marine Diatoms
While scarcely evident except to a very careful observer, a tidepooler armed with a hand lens or microscope will be able to see the most important of all the algae, MARINE DIATOMS.

A single-celled plant that somewhat resembles brown algae, DIATOMS can be found in filamentous colonies on rocks, shells, mud flats and on the surface of other plants. Each plant is enclosed in a tiny, two-part 'shell' made of silica (glass). In a sense, they live in a greenhouse of their own construction. Most diatoms are pelagic, meaning that they live in the water column in the open ocean. They are a major food source for filter feeders like mussels, clams and barnacles. Diatoms that live attached to rocks, shells or mudflats are grazed on by herbivores such as limpets, snails and chitons.

During the winter and spring "blooms" that occur naturally, an individual diatom, dividing once daily can produce a population of over one million in about three weeks. Certain invertebrates spawn or time the release of larvae during "blooms" or times of intense diatom abundance.

Oil Spill!
Some visitors were convinced the oil spill was a remnant of the New Carissa, others assumed it was a nearby and more recent spill. All were right on one thing: the dirty brown foam in the surfline and the dark streaks on the sand were evidence of an oil spill. At Cannon Beach and other places where land meets sea it's common and seasonal--and 100% natural. What you're witnessing is the release of oil from the internal structure of DIATOMS, the two-part silica shell that you can observe under the microscopes at our table on full program days. Diatoms, the plant that is responsible for producing more than 70% of the oxygen in our atmosphere, stores chemical energy (rearranged with the energy of the sun) in a small oil droplet inside its "house of glass."

The diatom population of the surf region is dominated almost exclusively by two colonial species: the centric diatom CHAETOCEROS and an associated smaller pennate form, ASTERIONELLA. These plants are present all year but the "blooms" that appear to be oil spills occur in late winter and early spring. As the populations explode, many of the diatoms die or are broken in the surf zone and release their oily material. The result of all this wave action and plankton multiplication is a part of spindrift, or surf foam, that on first glance can look like a man-made oil spill--one of the worst things to wash up on a beach. But you'll never see this event on the ten o'clock news. It's an oil spill alright, but it's Mother Nature at work, and it's a sign of a healthy beach.

For more information on these amazing plants, check out our online Marine Diatoms fact sheet.

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