Where is phytoplankton found in the ocean

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.

Recent research suggests the vigorous winter mixing sets the stage for explosive spring growth by bringing nutrients up from deeper waters into the sunlit layers at the surface and separating phytoplankton from their zooplankton predators. In the subtropical oceans, by contrast, phytoplankton populations drop off in summer. As surface waters warm up through the summer, they become very buoyant.

With warm, buoyant water on top and cold, dense water below, the water column doesn't mix easily. Phytoplankton use up the nutrients available, and growth falls off until winter storms kick-start mixing. In lower-latitude areas, including the Arabian Sea and the waters around Indonesia, seasonal blooms are often linked to monsoon-related changes in winds. As the winds reverse direction offshore versus onshore , they alternately enhance or suppress upwelling, which changes nutrient concentrations.

In the equatorial upwelling zone, there is very little seasonal change in phytoplankton productivity. In spring and summer, phytoplankton bloom at high latitudes and decline in subtropical latitudes. These maps show average chlorophyll concentration in May — left and November — right in the Pacific Ocean. ENSO cycles are significant changes from typical sea surface temperatures, wind patterns, and rainfall in the Pacific Ocean along the equator.

Compared to the ENSO-related changes in the productivity in the tropical Pacific, year-to-year differences in productivity in mid- and high latitudes are small. Because phytoplankton are so crucial to ocean biology and climate, any change in their productivity could have a significant influence on biodiversity, fisheries and the human food supply, and the pace of global warming.

Many models of ocean chemistry and biology predict that as the ocean surface warms in response to increasing atmospheric greenhouse gases, phytoplankton productivity will decline.

Productivity is expected to drop because as the surface waters warm, the water column becomes increasingly stratified ; there is less vertical mixing to recycle nutrients from deep waters back to the surface. Krill may be the most well-known type of zooplankton; they are a major component of the diet of humpback, right, and blue whales.

During the daylight hours, zooplankton generally drift in deeper waters to avoid predators. But at night, these microscopic creatures venture up to the surface to feed on phytoplankton.

This process is considered the largest migration on Earth; so many animals make this journey that it can be observed from space. Plankton are incredibly important to the ocean ecosystem, and very sensitive to changes in their environment, including in the temperature, salinity, pH level, and nutrient concentration of the water. When there are too many of certain nutrients in the water, for instance, harmful algal blooms like red tides are the result.

Because many zooplankton species eat phytoplankton, shifts in timing or abundance of phytoplankton can quickly affect zooplankton populations, which then affects species along the food chain. Researchers are studying how climate change affects plankton , from the timing of population changes to the hardening of copepod shells, and how those effects ripple through ecosystems. Phytoplankton growth is often limited by the scarcity of iron in the ocean.

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. Phytoplankton also require inorganic nutrients such as nitrates, phosphates, and sulfur which they convert into proteins, fats, and carbohydrates.

Plankton are marine drifters — organisms carried along by tides and currents. Numerous species of phytoplankton are known to bioluminesce, and the glow can be seen in oceans worldwide at all times of year.

Not exactly bioluminescent plankton — this is a squid that emits light along its entire body.