Where is plankton found in the ocean

They also require trace amounts of iron which limits phytoplankton growth in large areas of the ocean because iron concentrations are very low.

Other factors influence phytoplankton growth rates, including water temperature and salinity, water depth, wind, and what kinds of predators are grazing on them. Phytoplankton can grow explosively over a few days or weeks. This pair of satellite images shows a bloom that formed east of New Zealand between October 11 and October 25, When conditions are right, phytoplankton populations can grow explosively, a phenomenon known as a bloom. Blooms in the ocean may cover hundreds of square kilometers and are easily visible in satellite images.

A bloom may last several weeks, but the life span of any individual phytoplankton is rarely more than a few days. Phytoplankton are the foundation of the aquatic food web, the primary producers , feeding everything from microscopic, animal-like zooplankton to multi-ton whales. Small fish and invertebrates also graze on the plant-like organisms, and then those smaller animals are eaten by bigger ones.

Phytoplankton can also be the harbingers of death or disease. These toxic blooms can kill marine life and people who eat contaminated seafood. Dead fish washed onto a beach at Padre Island, Texas, in October , following a red tide harmful algal bloom.

Phytoplankton cause mass mortality in other ways. In the aftermath of a massive bloom, dead phytoplankton sink to the ocean or lake floor. The bacteria that decompose the phytoplankton deplete the oxygen in the water, suffocating animal life; the result is a dead zone.

Through photosynthesis, phytoplankton consume carbon dioxide on a scale equivalent to forests and other land plants. Some of this carbon is carried to the deep ocean when phytoplankton die, and some is transferred to different layers of the ocean as phytoplankton are eaten by other creatures, which themselves reproduce, generate waste, and die.

Phytoplankton are responsible for most of the transfer of carbon dioxide from the atmosphere to the ocean. Carbon dioxide is consumed during photosynthesis, and the carbon is incorporated in the phytoplankton, just as carbon is stored in the wood and leaves of a tree.

Most of the carbon is returned to near-surface waters when phytoplankton are eaten or decompose, but some falls into the ocean depths. Even small changes in the growth of phytoplankton may affect atmospheric carbon dioxide concentrations, which would feed back to global surface temperatures. Phytoplankton form the base of the aquatic food web. Phytoplankton samples can be taken directly from the water at permanent observation stations or from ships. Sampling devices include hoses and flasks to collect water samples, and sometimes, plankton are collected on filters dragged through the water behind a ship.

Marine biologists use plankton nets to sample phytoplankton directly from the ocean. Samples may be sealed and put on ice and transported for laboratory analysis, where researchers may be able to identify the phytoplankton collected down to the genus or even species level through microscopic investigation or genetic analysis. Although samples taken from the ocean are necessary for some studies, satellites are pivotal for global-scale studies of phytoplankton and their role in climate change.

Individual phytoplankton are tiny, but when they bloom by the billions, the high concentrations of chlorophyll and other light-catching pigments change the way the surface reflects light.

In natural-color satellite images top , phytoplankton appear as colorful swirls. Scientists use these observations to estimate chlorophyll concentration bottom in the water. These images show a bloom near Kamchatka on June 2, The water may turn greenish, reddish, or brownish. The chalky scales that cover coccolithophores color the water milky white or bright blue. Scientists use these changes in ocean color to estimate chlorophyll concentration and the biomass of phytoplankton in the ocean.

Phytoplankton thrive along coastlines and continental shelves, along the equator in the Pacific and Atlantic Oceans, and in high-latitude areas. Winds play a strong role in the distribution of phytoplankton because they drive currents that cause deep water, loaded with nutrients, to be pulled up to the surface.

These upwelling zones, including one along the equator maintained by the convergence of the easterly trade winds, and others along the western coasts of several continents, are among the most productive ocean ecosystems. By contrast, phytoplankton are scarce in remote ocean gyres due to nutrient limitations.

Phytoplankton are most abundant yellow, high chlorophyll in high latitudes and in upwelling zones along the equator and near coastlines. They are scarce in remote oceans dark blue , where nutrient levels are low. This map shows the average chlorophyll concentration in the global oceans from July —May View animation: small 5 MB large 18 MB. Like plants on land, phytoplankton growth varies seasonally.

In high latitudes, blooms peak in the spring and summer, when sunlight increases and the relentless mixing of the water by winter storms subsides. Every major phylum of the animal kingdom is represented in the zooplankton, at least by a larval stage.

Insects are a conspicuous absentee, and various hypotheses have been proposed to explain this [4]. Protozoa Gk. Together with small multi-cellular organisms they form the microzooplankton. As noted above, the distinction between plant and animal becomes blurred as we travel down towards the smaller end of the plankton size spectrum. Ciliates are a particularly important group of protozoa.

As their name suggests, they possess numerous hair-like features that fulfil several functional roles including movement, feeding and sensing the external environment. They play key roles in the microbial loop. Heterotrophic dinoflagellates frequently attack prey of equal or larger size than themselves. Some feed by engulfing their prey whole, while others suck out the contents of their prey via a feeding appendage called the peduncle.

Planktonic crustaceans are in many ways analogous to the insects on land. They typically dominate zooplankton communities, representing a crucial link in oceanic food chains. This refers to the jointed armour that envelops their bodies, made from a tough material called chitin Gk. This rigid external skeleton restricts the growth process, and must first be shed before an individual can increase in size.

Growth and development of all crustaceans is therefore achieved through a series of moults. It is common for the body form of an adult to be considerably different to that of the young. The abundance and biomass of copepods in our oceans defies belief. Some people maintain that copepods are the most numerous animal on our planet. They are found in all the seas on Earth, and have developed numerous strategies to survive in even the harshest conditions.

Copepods may be herbivorous, omnivorous, carnivorous or even detritivorous. They typically have an array of specialised feeding appendages that enable them to effectively sieve-out or grasp their food from the surrounding water. It is these oar-like feet that give copepods their name Gk. Kope , Podo ; oar-foot. The sheer numbers of these organisms necessitates that they play major roles in the ecology of our seas.

Copepods represent a crucial interface between phytoplankton and fish. They are often the first prey of fish larvae, so a healthy population of these tiny creatures is essential for healthy fish stocks. Euphausids are relatively large mm shrimp-like animals that are more commonly known as krill.

They are thought be omnivores, filtering out phytoplankton and similar-sized microzooplankton from seawater. Krill are often found in large swarms. This is thought to confuse predators that are searching for an individual. Euphausids Gk. Phausis ; Shining light are so-called because they have light-producing organs. Exactly why they produce light remains unknown.

It may be involved in mate-location, social interaction or camouflage. Krill are super-abundant, particularly in the polar seas.

They represent a staple food source for a diverse array of animals, ranging from fish and penguins to seals and whales. Amphipods are another important type of planktonic crustacean.

They have large sometimes enormous , well-developed eyes at the front of their head. These, together with pincer-type feeding appendages, are used to actively seek-out and capture their prey. Some amphipods have a tendency to swarm like krill, whereas others live in association with gelatinous organisms such as jellyfish and salps. Upper ocean amphipods are eaten by an array of larger animals, including fish, birds and marine mammals. Deep water amphipods are important scavengers, and are always amongst the first animals to arrive when a new food source becomes available.

Many crustacean zooplankton undertake a daily migration, moving into the upper, food-rich waters at night, and descending into the inky depths during the day. This behaviour continues throughout the winter, despite the surface layers being devoid of food. They have soft, translucent and often fragile bodies. The latter makes them notoriously difficult to sample in a quantitative manner. This has led to the significance of gelatinous organisms in marine ecosystems being underestimated historically.

A common feature of all jellies is that they are carnivorous, although some contain endosymbiotic algae that provide sugars and other carbohydrates via photosynthesis. Jellyfish are in fact not fish at all. They belong to a collection of organisms known as cnidarians.

They are distinguished by the presence of nematocysts or cnidocytes which are stinging cells. These serve as efficient weapons, firing tiny dart-like structures that deliver neurotoxins into their prey. Jellyfish are known to form large blooms. This largely reflects their seasonal reproductive efforts. It has been suggested that the frequency and magnitude of jellyfish blooms has increased as a result of overfishing.

However, there are currently too few data to substantiate or refute this claim. Jellyfish are consumed by other jellyfish, as well as fish and turtles.

Ctenophores are distinct from jellyfish because they do not possess nematocysts. Research in many branches of oceanography is discovering the vast unknown of the marine world, and has expanded interest in the understanding of the marine environment and the role each member plays in a complex community.

The free-floating organisms known as plankton, from the Greek "wandering," are the drifters of the ocean. Although most of these organisms are motile moving , they cannot swim or move against currents, but they can move vertically in the water column. Many marine plankton are found in the deep waters of the outer ocean, or pelagic waters, whereas others are found in the shallow waters known as the neritic zone.

Many of the neritic plankton are known as meroplankton, and spend only a brief period of their life cycle in the planktonic category. Many pelagic forms, such as the holoplankton, are planktonic during their entire lifespan. Many kinds of marine and fresh-water organisms utilize inorganic carbon as carbon dioxide and fix it into organic compounds by photosynthesis. This vial of plankton illustrates the small sizes: some are barely visible to the naked eye, and some are visible only through a microscope.

Plankton form the basis of aquatic food webs, including the ocean. The principal taxa of microscopic planktonic producers, primary producers , are found over most of the world's oceans, lakes, rivers, and estuaries, and comprise the base of the food web.

Phytoplankton consist primarily of diatoms, dinoflagellates, coccolithophorids, silicoflagellates, bacteria, and viruses. All of the organisms discussed below are key players in the microbial food web. Diatoms have cell walls of silica and pectin, and float in the water column or attach to surfaces as single cells or chains.

They are one of the major contributors to primary production in coastal waters, and occur everywhere in the ocean, but are most abundant in colder, nutrient-rich, nearshore waters.

Cell division occurs by fission, which is accompanied by a reduction in cell size. They are one of the principal groups that fix carbon through photosynthesis, and this production is prominent during seasonal blooms of short duration. Dinoflagellates occur as single cells, either naked or within a cellulose cell wall, and many species use flagella to move. These organisms are sometimes classified as protozoa and algae because of their ability to photosynthesize and also absorb nutrients by being parasitic, or by ingesting organic particles.

They are second to diatoms in contributing to primary production, and are widespread in the oceans, but are most abundant in nutrient-poor waters offshore.

Reproduction is by cell division. Some species are bioluminescent emitting a pale blue glow seen at night. Dinoflagellates often are the cause of red and brown tides, so named because the algal pigments give the water a colored tint.

Coccolithophorids are single-celled organisms. Many are flagellated, and are protected by ornate calcareous plates, called coccoliths, embedded in a gelatinous sheath that surrounds the cell. These organisms may form cysts that produce spores to produce new individuals. They are most abundant in warm, open-ocean waters, and are sometimes found nearshore.

The microscopic phytoplankton shown here are mainly comprised of diatoms and dinoflagellates. Other phytoplankton in the microscopic ranges include coccolithophorids, silicoflagellates, bacteria, and viruses. Some phytoplankton are much larger. Silicoflagellates occur as single flagellated cells and typically secrete a silicious outer skeleton.

Like coccoliths, these organisms are both autotrophic and heterotrophic , and are most abundant in cold, nutrient-rich waters. Bacteria are prokaryotes with cell walls made of chitin , and occur as single coccoid cells or long filaments.

They often are restricted to waters with low oxygen, and are important in the metabolism of aquatic ecosystems. To support their metabolism, they obtain nutrients by the uptake of organic matter and the release of exoenzymes to lyse distintegrate or dissolve particulate organic matter, and attack diatoms, dinoflagellates, and flagellates. Blue-green algae, or cyanobacteria, are photosynthetic. Bacterial activity in marine waters is strongly affected by availability of nutrients and organic matter.

Their productivity increases as phytoplankton productivity increases.