Classification of plankton:
- Planktons are a diverse group of small organisms that drift in the water column of oceans and seas.
| Aspect | detail |
| Study of Plankton | The scientific study of plankton is called Planktology. |
| Term coined by | The term plankton was coined by the German biologist Victor Hensen in 1887. |
| Meaning of Plankton | The term “plankton” is derived from the Greek word “planktos,” meaning “wanderer” or “drifter.” |
Classification of plankton based on primary function
| Characteristic | Phytoplankton | Zooplankton |
| Introduction
| · Phytoplanktons are the primary producers of the planktonic community. · They carry out photosynthesis to produce their own food. · These serve as the foundation of the marine food chain.
| · Zooplanktons are consumers that feed on other planktonic organisms, including phytoplankton and smaller zooplankton. · Zooplanktons are an essential link in transferring energy through the marine food web.
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| Habitat | · Found in water column of oceans, lakes, etc. | · Found in water column of oceans, lakes, etc. |
| Movement | · Drift with water movement | · Some have limited movement, mainly drift |
| Nature of nutrition | · Autotrophic as they can produce their own food. | · Heterotrophic and consume other organisms. |
| Role in Food Web | · They are primary producers | · They are consumers |
| Primary Pigment | · Have chlorophyll | · Chlorophyll is absent |
| Ecological Importance | · Produce oxygen, carbon fixation, nutrient cycling | · Transfer energy through food webs |
| Cell Wall | · Typically present, made of silica or cellulose | · Generally absent or soft exoskeleton |
| Type of Reproduction | · Asexual (binary fission) and sexual. | · Both type of sexual and asexual reproduction. |
| Size Range | · They can be microscopic to macroscopic. | · They also can be microscopic to macroscopic. |
| Examples | · Diatoms, · Dinoflagellates | · Copepods · krill · jellyfish |
Classification of plankton based on habitat
| Plankton Group | Habitat Description | Examples |
| Marine Plankton | Inhabit open ocean away from the coast | · Pelagic phytoplankton · Zooplankton |
| Coastal Plankton | Found in nearshore or coastal waters | · Coastal phytoplankton · Coastal zooplankton |
| Freshwater Plankton | Inhabit freshwater bodies like lakes and rivers | · Lentic phytoplankton · Lotic zooplankton |
| Estuarine Plankton | In transitional zones where freshwater meets saltwater | · Estuarine phytoplankton · Estuarine zooplankton |
| Benthic Plankton | Inhabit the bottom sediment of aquatic environments | · Benthic diatoms · Benthic zooplankton |
| Polar Plankton | Found in polar regions like the Arctic and Antarctic | · Polar diatoms · Polar copepods |
| Deep-Sea Plankton | Inhabit the deep ocean at great depths | · Deep-sea jellies · Deep-sea krill |
| Aeroplankton | Planktonic organisms suspended in the air | · Airborne algae · Pollen · Spores |
| Geoplankton | Planktonic organisms suspended in water or sediment of caves | · Cave-dwelling microorganisms |
Classification of plankton based on size
| Size Category | Size Range | Examples |
| Mega-Plankton
| > 20 cm
| · Larger organisms that are still considered planktonic. · Jellyfish and some types of larval fish. |
| Macro-Plankton | 2 cm – 20 cm | · Krill · larger copepods |
| Mesoplankton | 0.2 mm – 20 cm | · Small copepods · shrimp larvae |
| Microplankton | 20 μm – 0.2 mm | · Diatoms · Small copepods · Dinoflagellates |
| Nanoplankton | 2 μm – 20 μm | · These may include smaller types of phytoplankton and very tiny zooplankton. |
| Picoplankton | 0.2 μm – 2 μm | · Very small bacteria · cyanobacteria |
| Femtoplankton | < 0.2 μm | · Viruses |