50 Fun Facts About Plankton

The word 'plankton' comes from a Greek word meaning what?

Drifter or wanderer, from the Greek planktos. The name describes a way of life, not a size: anything that cannot swim against the current counts, from single cells to jellyfish.

What is the scientific term for a single organism of the plankton?

A plankter. You need a microscope to see most of them, yet a bloom can cover hundreds of square kilometres and show up in satellite images.

Which whale feeds almost exclusively on krill, the shrimp-like animals of the plankton?

Blue whale. The largest animal known to have lived survives on prey a few centimetres long, sieving several tonnes of krill a day through the baleen plates in its mouth.

Organisms such as fish and squid that can swim against currents, unlike plankton, are called what?

Nekton, from the Greek for 'swimming'. Membership can change with age: most fish and squid hatch as plankton and join the nekton only once they are strong enough to swim against the current.

Phytoplankton release about as much oxygen each year as all the world's what?

Land plants. They manage it by living fast: a single phytoplankton cell rarely lasts more than a few days, while a tree can stand for decades.

Which group of plankton grazes on phytoplankton and is in turn eaten by fish and whales?

Zooplankton. Not all of them are tiny or permanent: the group takes in jellyfish, and the newly hatched young of crabs, snails and fish that later leave the plankton behind.

What name is given to animals, such as oysters and starfish, that belong to the plankton only as larvae?

Meroplankton, from mero-, 'part'. Riding the currents is how slow seabed animals travel: an oyster or starfish that barely moves as an adult sends its larvae off to settle somewhere new.

What name is given to the tiny organisms, spores and pollen carried through the atmosphere by the wind?

Aeroplankton. Dust storms and sea spray lift spores, pollen and countless living cells high into the air, where winds can carry them across oceans before they settle back to earth.

What is the shower of organic detritus that sinks from the sunlit ocean to feed deep-sea life called?

Marine snow. The flakes are scraps of dead plankton, droppings and dust that clump together as they fall, growing to several centimetres across and sinking for weeks before they reach the seabed.

What kills an estimated fifth of the ocean's single-celled life every single day?

Viruses. They are the most abundant biological entities in the sea, and each cell they burst spills its contents back into the water as food for other plankton.

Some nutrient-rich stretches of ocean stay almost bare of phytoplankton because the water lacks which trace element?

Iron. Oceanographer John Martin quipped in 1988, 'Give me a half tanker of iron, and I will give you an ice age', and a trial soon after his death showed that a sprinkling of iron really does make such waters bloom.

Diatoms are encased in a cell wall made of what?

Silica. The glassy shell cannot stretch, and at each division a daughter cell builds its new half inside the old one, so a diatom population shrinks generation by generation until sex resets the size.

Diatomaceous earth, a powder of fossil diatom shells, kills bed bugs and fleas mainly by doing what to them?

Drying them out. The powder is not a poison: it soaks up the oily, waxy coating on an insect's shell, and without that waterproofing the insect loses its water and dies.

Fossilised diatom shells form a soft rock used in toothpaste, filters and, famously, to stabilise which explosive?

Dynamite. Alfred Nobel found that soaking liquid nitroglycerine into the powdery rock turned a dangerously unstable explosive into a paste that could be shaped into rods and handled far more safely.

Dinoflagellates take their name from Greek and Latin words meaning what?

Whirling whip. Each cell carries two whip-like flagella, and their beating sends it spinning through the water, the motion the first observers named it for.

A 'red tide' is usually a harmful bloom of which kind of plankton?

Dinoflagellate. Clams, mussels and oysters that feed on the bloom store its nerve toxin in their flesh, so the danger reaches people through a plate of seafood.

The glowing plankton Noctiluca flashes blue at night when the water around it is what?

Disturbed. Each cell flashes when something jolts it, which is why breaking waves and the wakes of boats can glow after dark.

Coccolithophores cover themselves in plates made of what?

Calcium carbonate. The plates rain down to the seabed when the cells die, and over millions of years thick layers of them hardened into chalk and limestone.

Blooms of the coccolithophore Emiliania huxleyi turn the sea which colour, in swirls visible from space?

Pale turquoise. The colour is not the cells themselves but sunlight scattering off clouds of the tiny plates they shed into the water.

Cyclops, named after myth's one-eyed giant, is a common genus of which tiny crustaceans?

Copepods. Like the giant, a Cyclops has a single eye, and copepods like it carry the larvae of the guinea worm, which is why straining drinking water through cloth keeps that disease at bay.

During which recurring climate event does plankton growth in the equatorial Pacific slump as the trade winds weaken?

El Niño. The trade winds normally drag cold, nutrient-rich water up to the sunlit surface; when they slacken the supply stops and the phytoplankton go hungry.

The word 'krill' comes from which language, where it means 'small fry of fish'?

Norwegian. The animals are anything but small fry in importance: most of the larger creatures of the Antarctic, from seals to seabirds, depend on krill directly or indirectly.

The combined weight of all Antarctic krill is thought to be about the same as that of which species?

Humans. Each krill weighs only a gram or two, yet together they come to hundreds of millions of tonnes, in swarms that can pack tens of thousands of animals into a cubic metre of sea.

When a huge plankton bloom dies and rots, the decay uses up what in the water, leaving a 'dead zone'?

Oxygen. Fertiliser washed off farmland is the usual trigger, which is why a dead zone forms each summer off the mouth of the Mississippi, where fish must flee or suffocate.

Prochlorococcus, the smallest photosynthetic organism known, went unnoticed in the sea until the 1980s; what is it?

Bacterium, and probably the most abundant photosynthetic organism on Earth: tiny as each cell is, there are so many of them that together they do a large share of all the photosynthesis in the sea.

Which bacterium of the open sea, with its close relatives, is thought to be the most abundant on Earth?

Pelagibacter ubique. It runs on one of the smallest genomes of any free-living cell, yet it and its relatives account for about a quarter of all the living cells in the ocean.

The largest animal migration on Earth, by weight, happens every night in the ocean, heading in which direction?

Up toward the surface. Countless small animals spend the day in the dark depths, hidden from predators, then rise after dusk to feed: a commute called diel vertical migration.

What is the plankton-driven ocean process that carries carbon from the atmosphere to the deep sea called?

The biological pump. Plankton take up carbon dioxide at the surface, and when they die or are eaten some of that carbon sinks, shifting roughly ten billion tonnes of it a year into the deep.

The remains of ancient plankton are the main raw material of which natural resource?

Crude oil. Dead plankton sank to ancient seabeds, were buried under sand and silt, and were slowly cooked by heat and pressure; coal, by contrast, began as the plants of swampy forests.

Foraminifera, or 'forams', are single-celled sea creatures with shells, whose Latin name means what?

Hole bearers. The shells have openings, between their chambers and often through their walls, and the cell casts out a net of fine threads to catch its food.

Diatoms found in the organs of a body recovered from water are used by forensic scientists as evidence of what?

Drowning. The idea is that only someone still breathing draws the tiny algae from the water deep into the body, though pathologists treat the test as supporting evidence, not proof.

Salps look like jellyfish, but as tunicates they are most closely related to which of these animals?

Frogs. Many tunicates start life as a tadpole-like larva with a notochord, the stiffening rod that defines the chordates, the phylum of every animal with a backbone, frogs and people included.

The planktonic snails known as 'sea butterflies' and 'sea angels' belong to which group?

Pteropods, 'wing-feet': the snail's foot has become a pair of flapping wings. Sea butterflies carry paper-thin shells, and those shells dissolve as seawater grows more acidic.

The eggs and larvae of fish found in the plankton are collectively called what?

Ichthyoplankton, from the Greek for 'fish'. Counting these eggs and larvae in net samples lets scientists judge how many adults are spawning without having to catch them.

The Continuous Plankton Recorder, towed behind merchant ships since 1931, traps plankton on a moving band of what?

Silk. Alister Hardy invented the recorder on an Antarctic voyage in the 1920s so that any ship could gather samples on its normal route, and it has since been towed millions of miles.

Which is the largest fish in the sea, a filter-feeder that lives mainly on plankton?

Whale shark. For all its size it is harmless to people: it gulps water near the surface and strains out plankton, fish eggs and small fish through screens in its gills.

Bright green blooms in lakes are usually caused by which organisms, popularly called blue-green algae?

Cyanobacteria. Not true algae at all, they remade the planet: their ancient relatives first filled the air with oxygen, and the chloroplast in every green plant descends from one.

What is the group of plankton that can both photosynthesise and eat called?

Mixoplankton. Far from being oddities, they may be the rule: a large share of the single-celled plankton once filed as plant-like turn out to hunt and swallow prey as well.

By weight, most of the living matter in the ocean is made up of what?

Microbes. Single-celled life outweighs all the sea's fish several times over, even though almost none of it can be seen without a microscope.

Dust from which desert blows across the Atlantic, feeding ocean plankton on the way and even fertilising the Amazon?

The Sahara. Much of the dust rises from the bed of a vanished lake in Chad, so the mud of a dead lake ends up nourishing plankton in mid-ocean and trees in Brazil.

Which venomous animal belongs to the neuston, life afloat on the sea's surface?

Portuguese man o' war. It cannot swim at all: a gas-filled float holds it at the surface like a sail, so wind and currents alone decide where it and its long stinging tentacles end up.

Satellites track the ocean's phytoplankton from orbit by measuring the colour of which pigment?

Chlorophyll. The pigment soaks up blue and red light, so the more phytoplankton there are, the greener the water looks from orbit.

Which shark, the second-largest fish in the sea, cruises with its huge mouth agape to sieve plankton?

Basking shark. It only looks as if it is sunbathing: it swims slowly along the surface straining plankton over its gills, and for all its bulk it is no danger to people.

Sailors' tales of 'milky seas', vast stretches of ocean glowing steadily at night, are thought to be the work of what?

Luminous bacteria. Sailors had described these glowing seas for centuries, but the first pictures came to light only in 2005, when scientists matched one ship's report to satellite images taken that same night.

Sheldon J. Plankton, the tiny green villain of SpongeBob SquarePants, owns which failing restaurant?

The Chum Bucket. Chum is fish bait, so almost nobody will eat there, which is why he keeps scheming to steal the Krabby Patty formula from the far busier Krusty Krab across the street.

In SpongeBob SquarePants, what is Plankton's wife Karen?

A computer. Creator Stephen Hillenburg, who taught marine biology before he turned to cartoons, named her after his own wife, Karen.

Who voices Plankton in SpongeBob SquarePants?

Jill Talley voices Karen; the pair started as minor characters before Lawrence built them into the main antagonists.

A 1961 mass poisoning of wildlife on the California coast, since blamed on toxic plankton, helped inspire which horror classic?

The Birds. Seabirds that had gorged on anchovies laced with a diatom toxin crashed into homes around Monterey Bay, and Alfred Hitchcock, already planning his film, took note of the local paper's report.

Filtering pond water through folded sari cloth to strain out plankton halved cases of which disease in Bangladeshi villages?

Cholera. The germ clings to tiny crustaceans in the water, so cloth folded four to eight times, fine enough to catch the plankton, takes most of it out with them.

Daphnia, tiny animals of pond and lake plankton, are better known by which name?

Water fleas. They are crustaceans, not insects: the name comes from the jerky, hopping way they swim, and they are widely raised as live food for aquarium fish.