Plankton

Many tiny things drift in the water.

They go where the waves flow. They cannot swim against the currents. These little ones are food for big whales.

Some drift in the air too. The wind carries them along. This can include tiny seeds. It can also include plant dust.

Most are too small to see. You need a tool to look at them. They live in lakes and rivers. They also live in the big ocean.

Light helps them grow. They need light to make food. This helps keep the water healthy. It is a busy world for them.

Plankton are living things that drift in water or air.

They cannot swim against currents or wind. They move where the water or air takes them. Some plankton stay in the water their whole lives. We call these holoplankton. Others are only plankton for a short time. These are called meroplankton. Many fish and crabs start as meroplankton.

Most plankton are tiny. They are often smaller than one millimeter. These tiny ones are called microplankton. They are very important for the ocean. They make much of the world's oxygen. They also make food for big animals.

Large whales and fish eat them.

Plankton need light and nutrients to grow. Light is very important for them. In the ocean, they mostly live near the surface. This is where they get the most light. They also need nutrients like nitrogen and phosphorus. Sometimes they need iron to grow well.

Some plankton even drift in the sky. We call these aeroplankton. The wind carries them through the air. This includes seeds and pollen.

Plankton are amazing living things that drift through water or air.

They are defined by how they move. Most plankton cannot swim against a current or the wind. Instead, they go wherever the water or air carries them. This is different from nekton, which are animals like fish that can swim against the flow.

Plankton can live in many places. They inhabit oceans, rivers, lakes, and even ponds. Some even drift in the sky as aeroplankton. This group includes everything from tiny bacteria to large jellyfish.

There are two main ways to group these drifters. Some stay in the plankton for their whole lives. Scientists call these holoplankton. This group includes most algae and some jellyfish. Other organisms are only plankton for a part of their lives. These are called meroplankton.

Many creatures, like starfish or fish, start as meroplankton. They live as tiny larvae before moving to the sea floor or swimming on their own. Most plankton are also very small. Microplankton are less than one millimeter wide. These tiny life forms make up a huge part of the ocean's biomass.

How does plankton grow and move? Most plankton need light from the sun to live. Because of this, they are often found near the water's surface. They also need nutrients like nitrate, phosphate, and silicate. In some parts of the ocean, there is plenty of light but not enough nutrients. In those places, plankton might grow better at deeper levels.

Sometimes, they need a special tiny nutrient called iron. Dust from large deserts, like the Sahara, can blow out to sea. This dust provides iron to the water. This helps tiny plants called phytoplankton grow in huge blooms.

Humans have studied these drifters for a long time. The name plankton was created by a German biologist named Victor Hensen. He named them in 1887. He used words from Greek to describe them. The Greek word "halos" means sea. The word "planaomai" means to drift or wander. Today, scientists use a special study called planktology to learn more. They use tools like aircraft, kites, and balloons to study aeroplankton in the sky. They also use microscopes to see the tiny microplankton. These tiny organisms are vital for the health of our whole planet.

Plankton are like the foundation of a giant building. Without them, the rest of the ocean could not exist. They are a key part of the marine food web.

Large animals like baleen whales and forage fish rely on them for food. Microplankton also do a very big job for the air we breathe. They produce much of the world's oxygen through photosynthesis. They also help cycle important things like carbon and nitrogen. Even the tiny viruses in the water play a role. They help control the size of plankton groups every day. This keeps the whole ocean in balance.

Plankton are organisms that drift through water or air. They are defined by their ecological niche and their level of motility. This means they lack the ability to actively propel themselves against currents or wind.

While some, like jellyfish, can swim slowly, they cannot overcome the influence of major currents. This distinguishes them from nekton, which are animals like fish that can swim against the flow. They also differ from benthos, which live on the deep sea floor. Plankton inhabit many environments, including oceans, estuaries, rivers, lakes, and ponds.

Scientists categorize plankton into several distinct groups based on their life cycles. Holoplankton are organisms that spend their entire lives as drifters. This group includes most algae, copepods, salps, and certain jellyfish. In contrast, meroplankton are only planktic for part of their lives. They usually begin as larvae before graduating to a different existence. Some become nekton, while others become benthic organisms living on the floor. Examples of meroplankton include the larvae of starfish, sea urchins, crustaceans, and most fish.

Microplankton make up a massive portion of the ocean's total biomass. These organisms are typically smaller than one millimeter in size. They are often categorized into two main types: phytoplankton and zooplankton. Phytoplankton, such as diatoms and dinoflagellates, are photosynthetic organisms. Zooplankton include various creatures like radiolarians, foraminifera, and copepods.

These microscopic life forms are considered ecological linchpins. They drive primary production and cycle essential nutrients like carbon, nitrogen, and phosphorus. They also sequester large amounts of carbon and produce much of the world's oxygen.

Plankton distribution is heavily influenced by the availability of light and nutrients. Most plankton ecosystems are driven by solar energy. This confines much of the primary production to surface waters where light is abundant. Nutrient availability, such as nitrate, phosphate, and silicate, is also a critical factor. In some tropical regions, light is plentiful but nutrients are limited due to water column stratification. This results in lower primary production at the surface. In these areas, production may occur at greater depths where light is reduced.

In certain ocean regions known as HNLC regions, productivity is low despite high macronutrient levels. These areas lack the micronutrient iron. Iron reaches the ocean primarily through the deposition of dust on the sea surface. Interestingly, areas near arid land often have abundant phytoplankton because of this. For example, trade winds carry dust from the Sahara Desert to the eastern Atlantic. This dust provides the necessary iron to trigger phytoplankton blooms.

The term "plankton" was coined in 1887 by the German marine biologist Victor Hensen. He derived the name from the Greek words "halos," meaning sea, and "planaomai," meaning to drift or wander. The study of these organisms is called planktology. A single planktonic individual is referred to as a plankter. While most plankton drift horizontally with currents, some exhibit diel vertical migration. This allows them to swim hundreds of meters vertically in a single day.

Plankton are not limited to aquatic environments; they also exist as aeroplankton. These are organisms that drift in the atmosphere, carried by wind currents. Aeroplankton includes plant spores, pollen, and wind-scattered seeds. It also contains microorganisms swept up from land by dust storms. Marine microorganisms can be propelled into the air via sea spray.

These airborne microbes can travel long distances to coastal regions. Once they land, they can impact the health of humans, animals, and vegetation. This shows how deeply connected the air and ocean systems are through these tiny drifters.