Animal of the Month
May 2016

Name: Plankton
Scientific Name: (Depends on the variant)
Classification: (varies wildly)
Number of Species: (Over a million)
Size: Varies. Many are microscopic. Some are single-celled.
A few are several-hundred feet!
Weight: N/A

Characteristics: (varies wildly)
Color(s): (varies wildly)
Preferred Habitat: Varies, is incapable of swimming well and
thus lives in the ocean currents.
Range: Across the sea
Diet: Some photosynthesize, others eat single-celled organisms
or other small crustaceans.
Lifespan: N/A

Status: (Not formally evaluated, but these life forms are threatened).

There is a group of creatures that are found across the ocean. These life forms are among the first life forms to have evolved on Earth, and they are integral to the web of life. They provide food for innumerable species of fish, crustacean, and whales, among many others. These creatures also generate a considerable amount of our planet’s oxygen. They truly are the basis of life on Earth. These amazing creatures are called plankton.

Plankton are a curious division of life because they are not any one particular species, or even a particular genus. Any life form that is unable to swim against water currents is considered plankton. The word plankton comes from the Greek word “planktos”, which means “wanderer” or drifter”. This group of lifeforms is incredibly diverse. Every large species of ocean-dwelling animal—everything form whales to crabs to sharks—only makes up two percent of the ocean’s biomass. The vast majority of the ocean’s biodiversity is made up of plankton species. Scientists are only beginning to understand the magnitude of plankton diversity, and how plankton affect our world. One teaspoon of sea water can contain as much as a million plankton!

There are two main forms of plankton. Phytoplankton are often single-celled and float at or near the surface. They use photosynthesis to create their own food. Algae count as phytoplankton. It is phytoplankton that absorb CO2 and produce oxygen. 50% of the air you breathe is produced by trees, and the other 50% of it came from plankton. 2.3 billion years ago, plankton brought about the Great Oxygenation Event, creating the oxygen atmosphere we breathe. This changed life on Earth forever. Life as we know it could not have existed without plankton.

The other type of plankton is zooplankton. The most common zooplankton are krill and copopods. Many of these plankton are single-celled, but they include the larval forms of fish, clams, crustaceans and sea urchins. Jelly fish are also a form of plankton! These plankton are the bread basket of the oceans. They are the food source for so many different animal species, being the first link in the web of life. Even some species of whales, the largest animals alive, feed on these teeny creatures! And it is the zooplankton that feed on phytoplankton, making phytoplankton the foundation of the food web in the ocean. Without plankton, the ocean would not be able to support life.

It is important to note that plankton are responsible for our petroleum products. Over the course of millions of years, plankton have lived and died at the bottom of the ocean. The sheer biomass of deceased plankton piled higher and higher on the sea floor and eventually became compressed. Some of the plankton fossilized into limestone, while others formed petroleum deposits. This petroleum has been extracted and used to create gasoline and a myriad of plastic and makeup products. Plankton have made the industrialization of humanity possible. Unfortunately, burning the extracted petroleum releases the CO2 that the plankton captured long ago. The increased levels of this gas lower our air quality, and capture more of the sun’s energy. This leads to higher temperatures on Earth. In addition, plastic is not a biodegradable product and if disposed of improperly can pose serious dangers to animals. There are predictions that there will soon be one ton of plastic in the ocean for every three tons of fish. Animals often try to eat the plastic and get tangled, or suffer from poisoning.

Plankton and their vital importance to life on Earth is simply not well known. While many know that plankton feed whales, it must be understood that plankton are the first links in the food chain. Without plankton, the ocean would be barren of almost all life. There would be no fish, no whales, no sharks, the list goes on. Then there is the misconception that plankton are just one kind of animal. This may have been reinforced by the cartoon Spongebob Squarepants. In Spongebob, the maniacal character Plankton repeatedly attempts to steal the secret formula to the famous krabby patty. Plankton in Spongebob is very small, which is accurate. However the rest of his anthropomorphized does not do justice to the many other forms of zooplankton or the phytoplankton. He is depicted as having one eye, a mouth, two antennae, very small arms and legs, teeth and a large eyebrow. Many plankton species have more than one eye, and some have no eyes! There are also many that do not have antennae or legs and arms. Many plankton do not have teeth, and of course none of them have anything close to an eyebrow.

Plankton are threatened, and this in turn threatens the security of the entire ocean. Studies have shown that plankton populations have dropped 40% since the 1950s. Plankton are increasingly facing pressure from ocean warming and acidification, which is largely caused by the burning of excessive fossil fuels. It is ironic that many of the fossil fuels that now threaten plankton are in fact fossilized plankton. Toxic chemicals and garbage that is dumped into the ocean are also not helping the situation. What’s more, there are companies that are beginning to extract plankton from the ocean as a source of energy powder or dog food! Plankton are too vital to the health of the planet to be harvested, they should be left alone! Every effort must be made to ensure the survival and success of plankton. Without plankton, nearly every organism in the ocean will stand to lose its food supply. There is also the risk that we will diminish the oxygen in our atmosphere, which will have negative consequences for every living creature on Earth.

If you would like to know more about the many bizarre plankton species, check out these awesome websites!

Plankton Chronicles—This series of videos illustrates the many forms of plankton and their importance.

Plankton Portal—Want to help scientists classify plankton? Here’s a good place to start! This website allows viewers to assist in classing plankton photographs to assist in scientific research.

Nature Works, Plankton page—A good introduction to the myriad of plankton types.

The Secret Life of Plankton—A brief but visually stunning introduction video by TEDEd, illustrating the importance of plankton.



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