Plankton - Definition, Types, Examples and Importance
Discover the plankton meaning, types, and importance in marine ecosystems. Learn with phytoplankton examples, zooplankton examples, and other plankton examples for NEET Biology, including notes, diagrams, MCQs, and previous year question papers.
Krati Saraswat13 Aug, 2025
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Plankton Definition: The plankton meaning comes from the Greek word meaning "drifter" or "wanderer," are minute organisms that inhabit aquatic environments and are transported by the movement of tides and currents. These organisms cannot effectively swim against these natural forces. Playing an essential role in marine ecosystems and the marine food chain, plankton is a significant food source for a wide array of large and small marine organisms. Additionally, they contribute significantly to the ocean's ecological balance by absorbing carbon dioxide and producing oxygen. Refer to the NEET Biology Notes in this article for in-depth details on plankton meaning in biology.
What is Plankton?
Plankton are tiny organisms found in both freshwater and saltwater environments. The term "plankton" describes organisms that cannot swim against currents, relying on water movements for their mobility. Examples include algae, protozoans, bacteria, mollusks, and coelenterates. Interestingly, larger organisms like jellyfish are also considered plankton due to their inability to swim against currents. Plankton form the base of the food chain, serving as the primary energy source for many larger animals. For instance, baleen whales use baleen plates to filter small organisms such as krill and plankton instead of teeth for chewing.Types of Plankton
Plankton are minuscule organisms that drift in various bodies of water, from vast oceans to freshwater lakes. They hold a pivotal position in the marine ecosystem, serving as the foundation of the food chain. Plankton can be categorised in two primary ways: by their size and by their position in the food chain.Classification of Plankton by Trophic Level
- Phytoplankton: These are plankton that resemble plants and are autotrophic, meaning they can produce their own food through the process of photosynthesis. Phytoplankton contribute significantly to global photosynthesis, generating oxygen and absorbing carbon dioxide. They exist in diverse forms, such as diatoms, cyanobacteria (commonly known as blue-green algae), dinoflagellates, and coccolithophores.
- Zooplankton: Heterotrophic plankton feeding on phytoplankton and bacteria. Common zooplankton examples include copepods, krill, foraminifera, and jellyfish.
- Mixoplankton: These organisms can function as both autotrophs and heterotrophs depending on the prevailing environmental conditions.
Classification of Plankton by Size
- Femtoplankton: These are the smallest plankton, measuring less than 0.2 micrometres. They are predominantly composed of viruses.
- Picoplankton: Ranging in size from 0.2 to 2 micrometres, picoplankton consist mainly of bacteria.
- Nanoplankton: These plankton are sized between 2 and 20 micrometres and include certain protists and small algae.
- Microplankton: Ranging from 20 to 200 micrometres, microplankton encompass most phytoplankton, some protozoans, and large protists.
- Mesoplankton: These plankton are of medium size, ranging from 0.2 to 20 millimetres. They include numerous copepods and other small crustaceans.
- Macroplankton: Macroplankton are larger plankton, measuring from 20 millimetres to 2 centimetres. They include jellyfish, salps, and some pteropods.
- Megaplankton: The largest type of plankton, megaplankton are greater than 2 centimetres in size. They include jellyfish, salps, squid, and some tunicates.
Plankton Examples
Plankton constitute a diverse array of organisms that drift or move weakly in aquatic environments. They exhibit a wide range of sizes and forms, ranging from minute bacteria to large jellyfish. Plankton serve as a fundamental component of the marine ecosystem, forming the base of the food chain.Importance of Plankton
The importance of plankton in the ecosystem can be outlined in several key points:- Oxygen Production: Plankton, particularly phytoplankton, play a essential role as producers, responsible for around half of the oxygen generated through photosynthesis.
- Food Source: Fisheries rely on plankton as a primary food source, highlighting their significance in marine food chains.
- Nutrient Recycling: Plankton contribute to nutrient recycling by converting dead organic matter into inorganic nutrients essential for plant growth.
- Carbon Dioxide Fixation: Phytoplankton aid in carbon dioxide fixation, a vital process for regulating greenhouse gas levels.
- Nitrogen Fixation: Certain plankton species can fix atmospheric nitrogen into ammonia and nitrates, essential nutrients for phytoplankton growth.
- Oxygen-Carbon Dioxide Balance: Both phytoplankton and zooplankton are essential for maintaining the balance of carbon dioxide and oxygen in the environment.
- Bioluminescence: Bioluminescent plankton contribute to the blue flashes of light seen in the sea, adding to the marine ecosystem's diversity and beauty.
- Harmful Algal Blooms: Some plankton species, like dinoflagellates, can lead to harmful algal blooms known as red tides, which can produce toxins harmful to marine life.
Plankton Plant
Plankton are small, often microscopic organisms that float in the ocean, serving as a essential part of marine ecosystems. While the term "plankton" typically brings to mind images of tiny animals, there are also plant-like plankton known as phytoplankton. Phytoplankton are responsible for producing around 50% of the world's oxygen through photosynthesis, making them essential to life on Earth. These microscopic plants form the base of the marine food web, providing food for various organisms, including zooplankton, fish, and even whales. Phytoplankton come in various shapes and sizes, from single-celled diatoms to long, chain-forming algae. They play a vital role in regulating the Earth's climate by absorbing carbon dioxide from the atmosphere. Learn more through NEET Biology Diagrams illustrating plankton meaning in biology.Plankton Fish
Plankton fish, also known as zooplankton, are small animals that drift with ocean currents. They are an essential food source for many marine animals, including small fish, shrimp, and whales. Zooplankton come in various forms, including tiny crustaceans, larval fish, and jellyfish. These tiny organisms are essential to the marine food chain, transferring energy from phytoplankton to higher trophic levels. Some zooplankton species undergo diel vertical migration, moving up to the surface at night to feed on phytoplankton and descending to deeper waters during the day to avoid predators.Plankton Algae
Plankton algae, or phytoplankton, are microscopic algae that float in the ocean's water column. These algae are primary producers, meaning they convert sunlight into energy through photosynthesis. Phytoplankton are incredibly diverse, with various species adapted to different environmental conditions. Like land plants, phytoplankton play a essential role in the carbon cycle, absorbing carbon dioxide from the atmosphere and converting it into organic matter. This process not only supports marine life but also helps regulate the Earth's climate by sequestering carbon. For a better understanding, refer to the Biology Syllabus, NEET Biology Notes, and Previous Year Question papers for diagrams and MCQs.Plankton FAQs
Is plankton a plant or animal?
There are two primary types of plankton: phytoplankton, which are plants, and zooplankton, which are animals. Zooplankton and other small marine creatures feed on phytoplankton and then become prey for fish, crustaceans, and other larger species.
What do plankton eat?
Zooplankton make up the animal component of the planktonic community. They are heterotrophic, meaning they cannot produce their own food and must consume other plants or animals. Specifically, they feed on phytoplankton.
Is plankton algae?
Marine plankton consists of bacteria, archaea, algae, protozoa, microscopic fungi, and drifting or floating animals found in the saltwater of oceans and the brackish waters of estuaries. Freshwater plankton are similar but are found in lakes and rivers.
Are plankton alive?
Plankton are a group of minuscule organisms that inhabit the surface and depths of lakes, rivers, ponds, and oceans worldwide. They derive their name from the Greek word planktos, meaning to drift or float.
Does plankton eat sunlight?
Most planktonic organisms require sunlight for survival because they are photosynthetic. They use the sun's energy to convert carbon dioxide and water into organic compounds through photosynthesis, enabling them to produce their own food and grow.
What is the meaning of plankton?
The plankton meaning is small or microscopic organisms drifting in water, including plant-like phytoplankton and animal-like zooplankton.
What is the role of plankton in the ocean?
Plankton produce oxygen, form the ocean’s food base, recycle nutrients, and help regulate carbon dioxide.
What is the role of ocean plankton?
Ocean plankton sustain marine food chains, maintain oxygen, carbon balance, and support global climate regulation.
What is Hypotonic solution?
A hypotonic solution is one in which the concentration of solutes is lower than inside a cell, causing water to move into the cell by osmosis, making it swell and possibly burst.
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