What do phytoplankton produce

For more than 20 years, Redfield and others puzzled over why these ratios were identical. He eventually made a crucial conceptual leap, proposing in that phytoplankton not only reflected the chemical composition of the deep ocean, but created it 1. He suggested that as phytoplankton and the animals that ate them died and sank to the bottom, along with those animals' faecal matter, microorganisms in the deep sea broke that material down into its chemical constituents, creating sea water with the same proportions of nitrogen and phosphorus.

The sea is not the only place where microorganisms shape the environment. Since Redfield's time, scientists have discovered that microorganisms also helped shape the chemical composition of our planet's air and land. Most dramatically, trillions of phytoplankton created the planet's breathable, oxygen-rich atmosphere. By analysing a variety of minerals in rocks of known age, geologists discovered that for the first half of Earth's 4.

They found rocks containing fossilized cyanobacteria, or blue-green algae, whose present-day cousins perform a type of photosynthesis that uses the Sun's energy to split water into hydrogen and oxygen. There were no land plants to produce oxygen until almost 2 billion years after atmospheric oxygen levels first rose.

It was the oxygen these photosynthetic microorganisms that created our oxygen-rich atmosphere. Today, different groups of microorganisms, especially in the ocean, recycle waste produced by other microorganisms and use it to power global cycles of the elements most essential to life. Different microorganisms convert amino acids and other organic nitrogen compounds to nitrogen-containing gases, returning them to the atmosphere.

And others help drive the recycling of different elements essential for life, including iron, sulphur and phosphorus. Phytoplankton provide organic matter for the organisms that comprise the vast majority of marine life.

They do this by consuming carbon dioxide that would otherwise dissolve in the sea water and make it more acidic. The organisms provide organic matter for the vast majority of the marine food chain. Removing carbon dioxide from water also allows more of it to diffuse in from the air, lowering atmospheric levels of the gas.

In these ways, phytoplankton are crucial to the global carbon cycle, the circular path by which carbon atoms travel from the atmosphere to the biosphere, to the land and then back to the ocean. How do we know how individual elements such as carbon move through our vast oceans and the atmosphere?

The first clues came in , when a Danish ecologist named Einar Steeman-Nielsen introduced an important technique that would shed light on how carbon cycles in the ocean.

It enabled scientists to measure an ocean ecosystem's primary productivity — the amount of organic matter that phytoplankton incorporate into their bodies through photosynthesis after meeting their own energy needs. To make this measurement, Steeman-Nielsen added bicarbonate containing a radioactive isotope of carbon called carbon to samples of sea water. When he exposed the samples to sunlight, the phytoplankton in the samples incorporated carbon into their tissues. By isolating the phytoplankton and measuring the radio-active decay of carbon in their cells, scientists could calculate the total amount of carbon dioxide fixed into organic matter.

Phytoplankton are the foundation of the ocean food web, providing organic matter for virtually all other marine creatures.

Their primary productivity limits the growth of crustaceans, fish, sharks, porpoises and other marine creatures, just as the primary productivity of land plants limits the growth of elephants, giraffes and monkeys.

By determining the productivity of phytoplankton, marine scientists can also determine how much carbon dioxide is being taken from the atmosphere. For three decades, oceanographers used Steeman-Nielsen's carbon technique to answer an important ecological question: how much organic matter do phytoplankton produce globally? The carbon technique helped them measure how quickly phytoplankton were fixing carbon at thousands of sites across the globe, but the estimates of primary productivity they generated were far too low.

They calculated that if the numbers were correct, the average phytoplankton in the ocean would take between 16 and 20 days to divide, but that didn't make sense to the biological oceanographers who were familiar with these organisms. The phytoplankton should have been growing much faster. Something was clearly wrong, but what? In the late s, chemist John Martin at the Moss Landing Marine Laboratory in California realized that the discrepancy occurred because of contamination.

Most of the seawater samples taken over the previous three decades had been inadvertently contaminated by heavy metals from the black rubber O-rings used to seal the sampling devices. Rubber products are chemically treated during manufacture to give them the correct mechanical properties. This process, called vulcanization, involves treating them with sulphur containing some zinc and tiny amounts of lead. These metals leached from the O-rings and other components into the seawater samples, where they poisoned the phytoplankton.

As a result, the measurements of primary production over three decades were compromised, causing scientists to seriously underestimate the importance of the world's oceans for the global carbon cycle. Martin and others developed new sampling techniques that kept samples as free as possible of lead and other trace metals, allowing more accurate measurements of phytoplankton's primary productivity. But there was still a problem. Even with thousands of measurements of primary productivity in the world's oceans, most of the ocean was still not being observed in any given month or year.

Mathematical methods could extrapolate from the primary productivity data to help fill in the gaps, but not well enough.

No one really knew how much carbon the world's phytoplankton pulled from the water around them. Obtaining reliable estimates of the ocean's primary productivity required a different approach. The CZCS took advantage of the fact that oxygen-producing photosynthesis only occurs in organisms that have a pigment called chlorophyll a. This pigment enables the phytoplankton to absorb blue light, which would otherwise be scattered by the sea water.

The more phytoplankton there are in an area of ocean, the more chlorophyll a there is and the darker the area appears from space. Oceanographers first calibrated the colour of the ocean in CZCS photographs with measures of primary productivity such as that developed by Steeman-Nielsen, and then used the colour measurements to obtain better mathematical estimates of phytoplankton productivity than were previously available.

The results from several groups of scientists showed that the world's phytoplankton incorporated a stunning 45—50 billion tonnes of inorganic carbon into their cells, twice the highest previous estimate. The importance of phytoplankton in converting carbon dioxide into plant and animal tissue became clear. How did phytoplankton's contribution compare with that of land plants? We found that land plants incorporated 52 billion tonnes of inorganic carbon each year, just half as much as ecologists had previously estimated.

Together, our results showed that we had vastly underestimated the global influence of the ocean's phytoplankton. This result surprised many ecologists, but the data were clear.

The phytoplankton in our oceans are less visible than the trees and grasses we see in our daily lives, but their influence is profoundly underappreciated. Phytoplankton were so important to the planet's carbon cycle that we now needed to reconsider the fate of dead phytoplankton.

Biologists set out to estimate the total biomass of phytoplankton and calculated that less than one billion tonnes of the single-celled microorganisms were alive in the ocean at any one time. There were 45 billion tonnes of new phytoplankton each year, 45 times more than their own mass at any given time. The phytoplankton would therefore have had to reproduce themselves entirely, on average, 45 times a year, or roughly once a week. In contrast, the world's land plants have a total biomass of billion tonnes, much of it wood.

The same calculations showed that the world's land plants reproduce themselves entirely once every ten years. Phytoplankton have no roots, trunks or leaves. So what was happening to all the organic matter they were absorbing? Biologists considered two scenarios. In the first, all the phytoplankton in the sunlit top metres of the ocean would be consumed in that layer by heterotrophs, animals and certain microorganisms that break down the phytoplankton's organic matter to obtain energy and nutrients to build their own tissues.

This process would produce carbon dioxide. The carbon dioxide would be instantly available to be taken up by other phytoplankton, which would use it and the Sun's energy to grow. In this situation, carbon dioxide levels in the sunlit top layer of the ocean would be in a steady state, and none of the gas would be pumped to the deep ocean.

In a second scenario, the dead bodies of phytoplankton and some of the faecal material and bodies of the heterotrophs would sink slowly below the top metres of the ocean. Like other plants, phytoplankton take in carbon dioxide and release oxygen. Phytoplankton rely on nutrients found in their surroundings, such as phosphate, nitrate, and calcium, to thrive.

In addition to phytoplankton and zooplankton, two even smaller kinds of plankton can be found floating in the sea. Bacterioplankton are bacteria and virioplankton are viruses. Plankton can be found in saltwater and freshwater. One way to tell if a body of water has a large plankton population is to look at its clarity. Very clear water usually has less plankton than water that is more green or brown in color.

While plankton populations are needed for thriving marine ecosystems, too many plankton in one area can create a serious environmental problem. These temporary conditions can cause high fish mortality and other damage to the marine ecosystem. Contaminated fish that are caught and served to people may also cause illness and even death. Because the aquatic food chain depends so heavily on plankton, the survival of these tiny plants and animals is essential for healthy marine ecosystems.

Climate change and rising sea temperatures pose serious risks to plankton populations. Department of the Interior Climate Science fellow whose research interests include the role of plankton in the marine food web. The more that scientists like Corradino understand how to protect these critical marine species, the more likely it is that their research will help creatures further up the food chain survive threats such as climate change.

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If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource. Some phytoplankton are bacteria, some are protists, and most are single-celled plants.

Among the common kinds are cyanobacteria, silica-encased diatoms, dinoflagellates, green algae, and chalk-coated coccolithophores. Phytoplankton are extremely diverse, varying from photosynthesizing bacteria cyanobacteria , to plant-like diatoms, to armor-plated coccolithophores drawings not to scale.

Like land plants, phytoplankton have chlorophyll to capture sunlight, and they use photosynthesis to turn it into chemical energy. They consume carbon dioxide, and release oxygen.

All phytoplankton photosynthesize, but some get additional energy by consuming other organisms. Phytoplankton growth depends on the availability of carbon dioxide, sunlight, and nutrients. Phytoplankton, like land plants, require nutrients such as nitrate, phosphate, silicate, and calcium at various levels depending on the species. Some phytoplankton can fix nitrogen and can grow in areas where nitrate concentrations are low.

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.