Plankton Tows and Red Tide Woes

Our biology 326 class was fortunate to visit Bamfield Marine Science Center recently. Among various other trips out into the field to get our feet wet, we collected plankton to bring back to the lab to look at.

Plankton although individually small are a huge part of the ecosystem. Plankton are the bottom of the food chain providing food for a wide variety of organisms and being prevalent primary producers. Plankton comes from the greek word to wander which is appropriate as plankton literally go with the flow. They are at the mercy of the current for transportation. Plankton’s daily migration through the water column covers the greatest distance than any other animal on the planet.
There are two major groups of plankton- phytoplankton and zooplankton. Phytoplankton are those that photosynthesize while zooplankton rely on eating other plankton as a food source whether it be phytoplankton or other zooplankton.
Here are a few of the more common or interesting varieties of plankton that we saw.

Some of the most common phytoplankton are diatoms. Diatoms are photosynthesizing silica-walled things of beauty. They are very abundant and their varying shapes tend to look like little knick-knacks when piled up together under a microscope. You are probably very familiar with these even if you are unaware of it- their silica walls are responsible for the gritty texture in many toothpastes and they are sometimes used as a pesticide in gardens.

Diatoms. Photo Cred: TESCAN

Diatoms. Photo Cred: TESCAN

One of the other commonly seen phytoplankton is the dinoflagellate. These guys are responsible for red tide when there are large blooms of them in the summer. Red tide is responsible for paralytic shellfish poisoning also known as the reason why we don’t eat shellfish from around Vancouver in the summer. Dinoflagellates aren’t all bad though, some are responsible for the bioluminesce seen at night on the ocean surface.

Dinoflagellate. Photo Cred: Christine Elder

Dinoflagellate. Photo Cred: Christine Elder

Zooplankton can include many different species of larvae. Among these is the porcelain crab larvae which is the unicorn of larvae. It has an elongated horn coming out the front of it and looks nothing like its adult form which doesn’t resemble any mythical creatures.

Porcelain Crab Larvae. Photo Cred: Peter J. Bryant

Porcelain Crab Larvae. Photo Cred: Peter J. Bryant

Copepods are another abundant member of zooplankton, in fact they may be the most abundant animal on earth. They move jerkily by paddling through the water with their antennae. They also only have one eye and their thin exoskeletons are transparent.

Copepod. Photo Cred: Micropolitan

Copepod. Photo Cred: Micropolitan

Plankton is incredibly diverse and this is just a small snapshot of some of the more abundant ones we were able to see in our tow sample in Bamfield. To learn more about plankton click here.


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