Plankton is not the name of a plant or animal but more of a category for any drifting organism that inhabits the middle to upper levels of the ocean, namely the pelagic zone.
Interestingly, the word plankton is Greek for “wanderer” or “drifter”. While some forms of plankton can move several hundreds of meters vertically in a single day (a behavior called vertical migration), their horizontal position is mostly determined by movement (currents) of the body of water they inhabit. Larger organisms, such as squid, fish, and marine mammals that can control their horizontal movement and swim against the average flow of the water environment, are called nekton. The study of plankton is termed planktology.
Plankton are also divided into 3 main types:
- Phytoplankton (from Greek phyton or plant), algae that live near the water surface where there is sufficient light to support photosynthesis
- Zooplankton (from Greek zoon or animal), small protozoa, crustaceans, jellyfish and various other animals that feed on other plankton. Some of the eggs and larvae of larger animals, such as fish, crustaceans, and annelids, are included here.
- Bacterioplankton, bacteria and archaea, which play an important role in absorbing nutrients dissolved in the water.
Common Plankton FAQ
Are jellyfish plankton?
Yes, they satisfy the 2 requirements to be called plankton: They live in the pelagic zone and they drift for a living. Technically they are zooplankton.
Where do plankton fit in the ocean food chain?
The oceanic food chain looks like this:
Phytoplankton → zooplankton → predatory zooplankton → filter feeders → predatory fish
As you can see, plankton inhabits the bottom layers of the food chain.
Neat Plankton Video:
Do plankton help with greenhouses gases?
Yes, according to this article they actually increase their numbers in response to increasing levels of dissolved CO2. However, as rising levels of CO2 are absorbed by the oceans’ phytoplankton — which account for about 30 percent of Earth’s natural CO2 processing — they are becoming acidic (as CO2 is absorbed carbonic acid is released).
Furthermore, as ocean currents warm, upwelling which carries essential nutrients are prevented, and 40 percent of Earth’s phytoplankton— the base of the entire ocean food chain — is missing.
According to Professor Jean-Pierre Gattuso of the National Center for Scientific Research in France the Arctic Ocean is becoming so acidic it will dissolve shells of sea creatures within 10 years.
- Plankton live in lakes and oceans
- Plankton makes up the first layer of the oceanic food chain
- Only bacteria outnumber plankton
- Plankton outweigh all the sea animals
- Fish larva start off life as plankton as they are ‘drifters’
What do plankton eat?
Lower level plankton like phytoplankton rely on the sun for photosynthesis. Upper level plankton like zooplankton feed on the phytoplankton.
What eats plankton?
All filter feeders like baleen whales, clams, krill, sponges, herring and other plankton.
Algae and plankton
All algae are plankton, but not all plankton are algae. Algae are considered phytoplankton as they inhabit the top layer of sunlit waater and rely on photosynthesis for food.
How many species of plankton are there?