This stomach-churning photograph shows the types of microscopic creatures that are crawling around in just a drop of seawater, which has been magnified 25 times to reveal what's living in it. From bacteria and worms, to fish eggs, crab larvae and diatoms, the image shows the plankton holidaymakers could be swallowing each time a splash of water ends up on their tongue. Award-winning National Geographic photographer David Liitschwager captured the photo, revealing the less-than-obvious threats in the ocean. The photo proves the taste of seawater isn't just salt - it's the multitude of critters.
On its website, National Geographic said of the photo: 'Under a magnifier, a splash of seawater teems with life. Using sophisticated techniques and equipment, I am sorting the phytoplankton communities in the Agulhas system based on how they fluoresce — that is, light up. This helps me to organise them by different species that perform different functions.
I focus on two nitrogen species; only one of them, nitrate, is responsible for drawing carbon down from the atmosphere. Additionally, I investigate the productivity of the ocean. This involves looking at which parts of this ocean basin have the most phytoplankton and where nutrient uptake is most efficient. I closely study and calculate the uptake rates of the nitrogen species and carbon export within this ocean basin. This is one of the very few studies looking closely at marine biogeochemistry of the Agulhas System Climate Array system.
Marine biogeochemistry is an interdisciplinary field of oceanography that deals with the relationships between marine chemistry, marine biological and geochemical processes with the aim to uncover the interactions and responses between ocean chemistry, marine biology and global change. My research will ultimately allow us to understand how the various phytoplankton communities in the Agulhas marine system take up different nitrogen species.
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This will ultimately help us understand how the planet cools itself in a warming world. Screen music and the question of originality - Miguel Mera — London, Islington. UEA Inaugural lecture: Alternative performance measures: do managers disclose them to inform us, or to mislead us? 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.
Importance of phytoplankton
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.
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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.
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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.
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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.
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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.