Plankton are the diverse collection of organisms that live in large bodies of water and are unable to swim against a current. The individual organisms constituting plankton are called plankters. They provide a crucial source of food to many large aquatic organisms, such as fish and whales.
These organisms include bacteria, archaea, algae, protozoa and drifting or floating animals that inhabit—for example—the pelagic zone of oceans, seas, or bodies of fresh water. Essentially, plankton are defined by their ecological niche rather than any phylogenetic or taxonomic classification.
Though many planktonic species are microscopic in size, plankton includes organisms over a wide range of sizes, including large organisms such as jellyfish. Technically the term does not include organisms on the surface of the water, which are called pleuston—or those that swim actively in the water, which are called nekton.
The name plankton is derived from the Greek adjective πλαγκτός (planktos), meaning errant, and by extension, wanderer or drifter, and was coined by Victor Hensen in 1887. While some forms are capable of independent movement and can swim hundreds of meters vertically in a single day (a behavior called diel vertical migration), their horizontal position is primarily determined by the surrounding water movement, and plankton typically flow with ocean currents. This is in contrast to nekton organisms, such as fish, squid and marine mammals, which can swim against the ambient flow and control their position in the environment.
Within the plankton, holoplankton spend their entire life cycle as plankton (e.g. most algae, copepods, salps, and some jellyfish). By contrast, meroplankton are only planktic for part of their lives (usually the larval stage), and then graduate to either a nektic (swimming) or benthic (sea floor) existence. Examples of meroplankton include the larvae of sea urchins, starfish, crustaceans, marine worms, and most fish.
The study of plankton is termed planktology and a planktonic individual is referred to as a plankter. The adjective planktonic is widely used in both the scientific and popular literature, and is a generally accepted term. However, from the standpoint of prescriptive grammar, the less-commonly used planktic is more strictly the correct adjective. When deriving English words from their Greek or Latin roots, the gender-specific ending (in this case, "-on" which indicates the word is neuter) is normally dropped, using only the root of the word in the derivation.
Plankton are primarily divided into broad functional (or trophic level) groups:
Recognition of the importance of mixotrophy as an ecological strategy is increasing, as well as the wider role this may play in marine biogeochemistry. Studies have shown that mixotrophs are much more important for the marine ecology than previously assumed, and comprise more than half of all microscopic plankton.
Plankton are also often described in terms of size. Usually the following divisions are used:
|Megaplankton||> 20 cm||metazoans; e.g. jellyfish; ctenophores; salps and pyrosomes (pelagic Tunicata); Cephalopoda; Amphipoda|
|Macroplankton||2→20 cm||metazoans; e.g. Pteropods; Chaetognaths; Euphausiacea (krill); Medusae; ctenophores; salps, doliolids and pyrosomes (pelagic Tunicata); Cephalopoda; Janthinidae (one family of gastropods); Amphipoda|
|Mesoplankton||0.2→20 mm||metazoans; e.g. copepods; Medusae; Cladocera; Ostracoda; Chaetognaths; Pteropods; Tunicata|
|Microplankton||20→200 µm||large eukaryotic protists; most phytoplankton; Protozoa Foraminifera; tintinnids; other ciliates; Rotifera; juvenile metazoans - Crustacea (copepod nauplii)|
|Nanoplankton||2→20 µm||small eukaryotic protists; Small Diatoms; Small Flagellates; Pyrrophyta; Chrysophyta; Chlorophyta; Xanthophyta|
|Picoplankton||0.2→2 µm||small eukaryotic protists; bacteria; Chrysophyta|
|Femtoplankton||< 0.2 µm||marine viruses|
However, some of these terms may be used with very different boundaries, especially on the larger end. The existence and importance of nano- and even smaller plankton was only discovered during the 1980s, but they are thought to make up the largest proportion of all plankton in number and diversity.
Plankton inhabit oceans, seas, lakes, ponds. Local abundance varies horizontally, vertically and seasonally. The primary cause of this variability is the availability of light. All plankton ecosystems are driven by the input of solar energy (but see chemosynthesis), confining primary production to surface waters, and to geographical regions and seasons having abundant light.
A secondary variable is nutrient availability. Although large areas of the tropical and sub-tropical oceans have abundant light, they experience relatively low primary production because they offer limited nutrients such as nitrate, phosphate and silicate. This results from large-scale ocean circulation and water column stratification. In such regions, primary production usually occurs at greater depth, although at a reduced level (because of reduced light).
Despite significant macronutrient concentrations, some ocean regions are unproductive (so-called HNLC regions). The micronutrient iron is deficient in these regions, and adding it can lead to the formation of phytoplankton blooms. Iron primarily reaches the ocean through the deposition of dust on the sea surface. Paradoxically, oceanic areas adjacent to unproductive, arid land thus typically have abundant phytoplankton (e.g., the eastern Atlantic Ocean, where trade winds bring dust from the Sahara Desert in north Africa).
While plankton are most abundant in surface waters, they live throughout the water column. At depths where no primary production occurs, zooplankton and bacterioplankton instead consume organic material sinking from more productive surface waters above. This flux of sinking material, so-called marine snow, can be especially high following the termination of spring blooms.
Aside from representing the bottom few levels of a food chain that supports commercially important fisheries, plankton ecosystems play a role in the biogeochemical cycles of many important chemical elements, including the ocean's carbon cycle.
Primarily by grazing on phytoplankton, zooplankton provide carbon to the planktic foodweb, either respiring it to provide metabolic energy, or upon death as biomass or detritus. Organic material tends to be denser than seawater, so it sinks into open ocean ecosystems away from the coastlines, transporting carbon along with it. This process, called the biological pump, is one reason that oceans constitute the largest carbon sink on Earth. However, it has been shown to be influenced by increments of temperature.
It might be possible to increase the ocean's uptake of carbon dioxide (CO
2) generated through human activities by increasing plankton production through seeding, primarily with the micronutrient iron. However, this technique may not be practical at a large scale. Ocean oxygen depletion and resultant methane production (caused by the excess production remineralising at depth) is one potential drawback.
Phytoplankton absorb energy from the Sun and nutrients from the water to produce their own nourishment or energy. In the process of photosynthesis, phytoplankton release molecular oxygen (O
2) into the water as a waste biproduct. It is estimated that about 50% of the world's oxygen is produced via phytoplankton photosynthesis. The rest is produced via photosynthesis on land by plants. Furthermore, phytoplankton photosynthesis has controlled the atmospheric CO
2 balance since the early Precambrian Eon.
The growth of phytoplankton populations is dependent on light levels and nutrient availability. The chief factor limiting growth varies from region to region in the world's oceans. On a broad scale, growth of phytoplankton in the oligotrophic tropical and subtropical gyres is generally limited by nutrient supply, while light often limits phytoplankton growth in subarctic gyres. Environmental variability at multiple scales influences the nutrient and light available for phytoplankton, and as these organisms form the base of the marine food web, this variability in phytoplankton growth influences higher trophic levels. For example, at interannual scales phytoplankton levels temporarily plummet during El Niño periods, influencing populations of zooplankton, fishes, sea birds, and marine mammals.
The effects of anthropogenic warming on the global population of phytoplankton is an area of active research. Changes in the vertical stratification of the water column, the rate of temperature-dependent biological reactions, and the atmospheric supply of nutrients are expected to have important impacts on future phytoplankton productivity. Additionally, changes in the mortality of phytoplankton due to rates of zooplankton grazing may be significant.
Freshly hatched fish larvae are also plankton for a few days, as long as it takes before they can swim against currents.
Zooplankton are the initial prey item for almost all fish larvae as they switch from their yolk sacs to external feeding. Fish rely on the density and distribution of zooplankton to match that of new larvae, which can otherwise starve. Natural factors (e.g., current variations) and man-made factors (e.g. river dams) can strongly affect zooplankton, which can in turn strongly affect larval survival, and therefore breeding success.
The importance of both phytoplankton and zooplankton is also well-recognized in extensive and semi-intensive pond fish farming. Plankton population based pond management strategies for fish rearing have been practised by traditional fish farmers for decades, illustrating the importance of plankton even in man-made environments.
Aeroplankton (or aerial plankton) are tiny lifeforms that float and drift in the air, carried by the current of the wind; they are the atmospheric analogue to oceanic plankton.
Most of the living things that make up aeroplankton are very small to microscopic in size, and many can be difficult to identify because of their tiny size. Scientists can collect them for study in traps and sweep nets from aircraft, kites or balloons.The aeroplankton comprises numerous microbes, including viruses, about 1000 different species of bacteria, around 40,000 varieties of fungi, and hundreds of species of protists, algae, mosses and liverworts that live some part of their life cycle as aeroplankton, often as spores, pollen, and wind-scattered seeds.
A large number of small animals, mainly arthropods (such as insects and spiders), are also carried upwards into the atmosphere by air currents and may be found floating several thousand feet up. Aphids, for example, are frequently found at high altitudes.
Many species of spiders deliberately use the wind to propel themselves. The spider will find a vantage point (such as a branch, fence or surface) and, pointing its abdomen upward, eject fine threads of silk from its spinnerets. At some point, the force exerted by moving air upon the silk threads is great enough to launch the spider into the air. This is called ballooning. Such ballooning spiders (e.g. Linyphiidae) are capable of drifting many miles away from where they started. The flexibility of their silk draglines can aid the aerodynamics of their flight, causing the spiders to drift an unpredictable and sometimes long distance.Biotherm
Biotherm is a French luxury skin care company owned by L'Oréal under the Luxury Products division. Biotherm was acquired by L'Oréal in 1970.
Biotherm originated from mineral water. In early 20th century, the French doctor Jos Jullien discovered mineral thermal spring waters under Pyrenees mountain in the southern part of France which contained thermal plankton, supposedly a key to healthy skin and a potent skin rejuvenator. In 1952, intellectual property rights was acquired and she used it in skin care products. Thus, therm in Biotherm comes from thermal plankton, an ingredient found in all Biotherm products. Bio comes from the profession of the founder biologist.Continuous Plankton Recorder
The Continuous Plankton Recorder (CPR) Survey is one of the longest running marine biological monitoring programmes in the world. Started in 1931 by Sir Alister Hardy and Sir Cyril Lucas, the Survey has provided marine scientists with their only measure of plankton communities on a pan-oceanic scale. Today the CPR Survey is operated by the Marine Biological Association(MBA), located in Plymouth, UK. Uniquely, the CPR Survey’s methods of sampling and plankton analysis remain unchanged since 1948, providing a spatio-temporally comprehensive > 70 year record of marine plankton dynamics.Forage fish
Forage fish, also called prey fish or bait fish, are small pelagic fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food chain on plankton, often by filter feeding. They include particularly fishes of the family Clupeidae (herrings, sardines, shad, hilsa, menhaden, anchovies, and sprats), but also other small fish, including halfbeaks, silversides, smelt such as capelin, and the goldband fusiliers pictured on the right.
Forage fish compensate for their small size by forming schools. Some swim in synchronised grids with their mouths open so they can efficiently filter plankton. These schools can become immense shoals which move along coastlines and migrate across open oceans. The shoals are concentrated energy resources for the great marine predators. The predators are keenly focused on the shoals, acutely aware of their numbers and whereabouts, and make migrations themselves that can span thousands of miles to connect, or stay connected, with them.The ocean primary producers, mainly contained in plankton, produce food energy from the sun and are the raw fuel for the ocean food webs. Forage fish transfer this energy by eating the plankton and becoming food themselves for the top predators. In this way, forage fish occupy the central positions in ocean and lake food webs.The fishing industry catches forage fish primarily for feeding to farmed animals. Some fisheries scientists are expressing concern that this will affect the populations of predator fish that depend on them.Gelatinous zooplankton
Gelatinous zooplankton are fragile animals that live in the water column in the ocean. They have very delicate bodies that are easily damaged or destroyed. Gelatinous zooplankton are often transparent. All jellyfish are gelatinous zooplankton, but not all gelatinous zooplankton are jellyfish. The most commonly encountered organisms include ctenophores, medusae, salps, and Chaetognatha in coastal waters. However, almost all marine phyla, including Annelida, Mollusca and Arthropoda, contain gelatinous species, but many of those odd species live in the open ocean and the deep sea and are less available to the casual ocean observer. Gelatinous zooplankton have also been called "Gelata".Holoplankton
Holoplankton are organisms that are planktic (they live in the water column and cannot swim against a current) for their entire life cycle. Examples of holoplankton include some diatoms, radiolarians, some dinoflagellates, foraminifera, amphipods, krill, copepods, and salps, as well as some gastropod mollusk species. Holoplankton dwell in the pelagic zone as opposed to the benthic zone. Holoplankton include both phytoplankton and zooplankton and vary in size. The most common plankton are protists.Nekton
Nekton or necton refers to the aggregate of actively swimming aquatic organisms in a body of water. The term was proposed by German biologist Ernst Haeckel to differentiate between the active swimmers in a body of water, and the passive organisms that were carried along by the current, the plankton. As a guideline, nektonic organisms have a high Reynolds number (greater than 1000) and planktonic organisms a low one (less than 10). However, some organisms can begin life as plankton and transition to nekton later on in life, sometimes making distinction difficult when attempting to classify certain plankton-to-nekton species as one or the other. For this reason, some biologists choose not to use this term.Paradox of the plankton
In aquatic biology, the paradox of the plankton describes the situation in which a limited range of resources supports an unexpectedly wide range of plankton species, apparently flouting the competitive exclusion principle which holds that when two species compete for the same resource, one will be driven to extinction.Phytoplankton
Phytoplankton are the autotrophic (self-feeding) components of the plankton community and a key part of oceans, seas and freshwater basin ecosystems. The name comes from the Greek words φυτόν (phyton), meaning "plant", and πλανκτός (planktos), meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye. However, when present in high enough numbers, some varieties may be noticeable as colored patches on the water surface due to the presence of chlorophyll within their cells and accessory pigments (such as phycobiliproteins or xanthophylls) in some species.Picoplankton
Picoplankton is the fraction of plankton composed by cells between 0.2 and 2 μm that can be either prokaryotic and eukaryotic phototrophs and heterotrophs:
heterotrophic They are prevalent amongst microbial plankton communities of both freshwater and marine ecosystems. They have an important role in making up a significant portion of the total biomass of phytoplankton communitiesPlanktivore
A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton.Plankton and Karen
Sheldon J. Plankton and Karen Plankton are fictional characters in the American animated television series SpongeBob SquarePants. They are respectively voiced by Mr. Lawrence and Jill Talley. Their first appearance was in the episode "Plankton!" that premiered on July 31, 1999. They were created and designed by marine biologist and animator Stephen Hillenburg, the creator of the program, with additional character development by Lawrence.
Plankton and Karen are the owners of the unsuccessful Chum Bucket restaurant. Plankton is an intellectual planktonic copepod and Karen is a waterproof supercomputer. Plankton shares a rivalry with Mr. Krabs, who owns the far more profitable Krusty Krab restaurant and sells a fictional burger called the Krabby Patty. Plankton and Karen often devise schemes to steal the secret Krabby Patty recipe, but their efforts are always thwarted by Krabs and his employees.
Critical reception for Plankton and Karen has been positive, with praise directed toward their voices and dialogue together. They began as minor characters, but Lawrence developed their personalities throughout the show's early seasons and they eventually became the franchise's main antagonists. The Planktons play central roles in the 2004 theatrical film, which promoted them both to main cast members in its credits, and the 2015 sequel. They have also been featured in a variety of spin-off media, including tie-in publications, playsets and other merchandise.Sea apple
Sea apple is a common name for the colorful and somewhat round sea cucumbers of the genera Pseudocolochirus, found in Indo-Pacific waters. Sea apples are filter feeders with tentacles, ovate bodies, and tube-like feet. They can release their internal organs or a toxin into the water when stressed.SpongeBob SquarePants (season 10)
The tenth season of the American animated television series SpongeBob SquarePants, created by former marine biologist and animator Stephen Hillenburg, aired on Nickelodeon in the United States from October 15, 2016 to December 2, 2017. It opened with "Whirly Brains", and finished airing with "The Incredible Shrinking Sponge". The season was first announced on May 21, 2012. The series chronicles the exploits and adventures of the title character and his various friends in the fictional underwater city of Bikini Bottom. The season was executive produced by series creator Hillenburg, and was the first season of the show not to involve long-time crew member and former showrunner Paul Tibbitt. The showrunners for this season were Marc Ceccarelli and Vincent Waller, who also acted as supervising producers. It is the shortest season, containing 11 episodes (22 segments) instead of the usual 26-episode length.
The show received several accolades during the run of its tenth season, including the 2017 Kids' Choice Award for Favorite Cartoon. The series was also nominated in various international Kids' Choice Awards ceremonies for the same category. The show received a pending nomination at the BAFTA Children's Awards for the International category as well.SpongeBob SquarePants (season 11)
The eleventh season of the American animated television series SpongeBob SquarePants, created by former marine biologist and animator Stephen Hillenburg, began airing on Nickelodeon in the United States on June 24, 2017, beginning with the episode "Spot Returns"/"The Check-Up". The series chronicles the exploits and adventures of the title character and his various friends in the fictional underwater city of Bikini Bottom. The season was executive produced by series creator Hillenburg. The showrunners for this season were Marc Ceccarelli and Vincent Waller, who are also the supervising producers.
The season was first announced on March 3, 2016, along with the tenth season, and premiered on June 24, 2017. A total of 26 episodes (50 segments) were produced for the season, bringing the number of episodes up to 241.
The season concluded with the airing of "Goons on the Moon" on November 25, 2018.Stephen Hillenburg
Stephen McDannell Hillenburg (August 21, 1961 – November 26, 2018) was an American animator, voice actor, and former marine science educator. He was best known as the creator of the Nickelodeon animated television series SpongeBob SquarePants (1999–), which he also directed, produced, and wrote. It has gone on to become the fifth-longest-running American animated series.
Born in Lawton, Oklahoma and raised in Anaheim, California, Hillenburg became fascinated with the ocean as a child and developed an interest in art. He started his professional career in 1984, instructing marine biology, at the Orange County Marine Institute, where he wrote The Intertidal Zone, an informative comic book about tide-pool animals, which he used to educate his students. In 1989, two years after leaving teaching, Hillenburg enrolled at the California Institute of the Arts to pursue a career in animation. He was later offered a job on the Nickelodeon animated television series Rocko's Modern Life (1993–1996) after his success with The Green Beret and Wormholes (both 1992), short films that he made while studying animation.
In 1994, Hillenburg began developing The Intertidal Zone characters and concepts for what became SpongeBob SquarePants. The show has aired continuously since its premiere in 1999. He also directed The SpongeBob SquarePants Movie (2004), which he originally intended to be the series finale. However, Nickelodeon wanted to produce more episodes, so Hillenburg resigned as the showrunner. He went back to making short films, with Hollywood Blvd., USA (2013). In 2015, The SpongeBob Movie: Sponge Out of Water was released; the second film adaptation of the series, it marked Hillenburg's return to the franchise, wherein he co-wrote the story and acted as an executive producer on the project.
Besides his two Emmy Awards and six Annie Awards for SpongeBob SquarePants, Hillenburg also received other recognition, such as an accolade from Heal the Bay for his efforts on elevating marine life awareness, and the Television Animation Award from the National Cartoonists Society. Hillenburg was diagnosed with amyotrophic lateral sclerosis (ALS) in 2017, but stated he would continue to work on SpongeBob SquarePants as long as possible. He passed away due to complications of the disease on November 26, 2018, at the age of 57.Zooplankton
Zooplankton (, ) are heterotrophic (sometimes detritivorous) plankton (cf. phytoplankton). Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word zooplankton is derived from the Greek zoon (ζῴον), meaning "animal", and planktos (πλαγκτός), meaning "wanderer" or "drifter". Individual zooplankton are usually microscopic, but some (such as jellyfish) are larger and visible to the naked eye.