Unlike the cartoon SpongeBob Squarepants which you probably watched growing up (or still watch), organisms don’t live in pineapples under the sea. However, there are TONS of cool creatures living in the ocean. These include sponges (Spongebob), sea stars (Patrick), and plankton (Sheldon). You may have seen sponges and sea stars at your local aquarium, but perhaps not plankton. Plankton means “wanderer” in Greek; therefore, they drift along with the water’s currents. There are both plant plankton and animal plankton. These form the bottom of food chains and are very important in food webs.
Some plankton are large, including jellyfish that are two meters long! Others are smaller and require a microscope to see. This is how I observed plankton at Bamfield Marine Sciences Center. During the day, we collected plankton from various depths of Grappler Inlet. You might ask yourself, how does one retrieve plankton if some are extremely small? The technique we used is called a plankton tow and involves lowering a mesh net attached to a small jar into the ocean from a boat. After pulling the net from the water and opening the jar, you will see small bits. At first, you might not think these pieces look interesting; however, when you look under a microscope you will be amazed! There are coloured and clear plankton, others have appendages, and some even have eyes!
Animal plankton can be classified into two categories. The first group includes most marine invertebrates including crabs. These invertebrates have a juvenile planktonic stage but later develop into a non-planktonic adult. Other plankton remain planktonic their whole life. Sheldon the plankton, a copepod, is an example. Like Sheldon, most copepods have a singular eye and some can be parasitic. In one episode, Sheldon acts as a parasite by going inside SpongeBob’s “brain”!
At Bamfield, I also learned that plant plankton drift closer to the surface of the water to access sunlight for photosynthesis. However, animal plankton migrate from the depths of the ocean to the surface when the sun sets. It is thought that they do this to hide from predators during the day and feed at night. Even though plankton may be small, they are definitely smart. You might be thinking then, why did the plankton collection photo in shallow water also have animal plankton? Science doesn’t always behave as expected and Mother Nature can break the “rules”!
So remember, next time you see tiny specks in the sea…they could be living organisms! Check out this plankton Ted-Ed video with beautiful visuals narrated by a dead fish, who was also once a plankton! Also visit this animal plankton laboratory from Fisheries and Oceans Canada.
*Nickelodeon’s SpongeBob Squarepants theme song lyrics