The Importance of Plankton

Marine scientist, Dr. Richard Kirby, blogs on Blue Planet Society, March 2015: “In the sea, the planktonplankton Plankton is a generic term for a wide variety of the smallest yet most important organisms form that drift in our oceans. They can exist in larger forms of more than 20cm as the larval forms of jellyfish, squid, starfish, sea urchins, etc. and can be algae, bacterial or even viral down to as small as 0.2µm. They are nutrient and light dependent, and form the essential foodchain baseline for larger dependent aquatic lifeforms. Fish species rely on the density and distribution of zooplankton to coincide with first-feeding larvae for good survival of their larvae, which can otherwise starve. Man-made impacts such as dredging, dams on rivers, waste dumping, etc can severely affect zooplankton density and distribution, which can in turn strongly affect larval survival and thus breeding success and stock strength of fish species and the entire ecosystem. They also form the essential basis of CO2 take up in our seas ecosystem, hence Global Warming. begin the marine food chain.

Microscopic phytoplanktonphytoplankton Microscopic marine plants, usually algae. These microscopic plants are at the base of the food chain, and are the food of zooplankton (microscopic marine animals). Note: phytoplankton are microscopic plants, and zooplankton are microscopic animals. (tiny plant-like cells) use the sun’s energy to combine carbon dioxide and water to create sugar and oxygen in the process known as photosynthesis. Despite being tiny (each phytoplankton cell is smaller in diameter than a strand of human hair), they are so numerous that they account for about 50% of all photosynthesis on Earth. And here, tiny creatures and big numbers start to mix, since 50% of all photosynthesis equates to about 50 billion tonnes of carbon each year, or about 125 billion tonnes of sugar!

The phytoplankton are the food of herbivorous zooplanktonzooplankton Zooplankton form the group of tiny animals such as minuscule jellyfish and rotifers present in the marine environment. They are a major source of food for those higher up the food chain, and their numbers relate directly as a good indicator to the nutrient enrichment of the sea of the area. Note: phytoplankton are microscopic plants, and zooplankton are microscopic animals. (animal plankton) in turn eaten by carnivorous zooplankton. Together all the plankton are the food for fish, which in turn are eaten by other sea creatures such as seabirds, sharks, and seals, in their turn eaten by larger predators like killer-whales.

Phytoplankton and copepods are the first two steps in the plankton food chain

Phytoplankton and copepodscopepods A group of small crustaceans found in the sea and nearly every fresh water habitat. Some species are planktonic (drifting in sea waters), some are benthic (living on the ocean floor), and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds and puddles, damp moss, or water-filled recesses (phytotelmata) of plants such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as biodiversity indicators. are the first two steps in the plankton food chain

The plankton are also the food source of some of the largest mammals on Earth, the baleen whales. In this way the plankton food webfood web The totality of interacting food chains in an ecological community underpins and determines the amount of life in the sea. Quite simply, without the plankton there would not be any fish in the sea for you, me or other creatures to eat, and so that is why there wouldn’t be any polar bears on the ice.

Of course, as well as eating fish, we also consume many marine creatures that had a larval life in the plankton such as shrimps, crabs, and mussels etc. In some countries we also eat plankton too, such as Antarctic krill that is eaten in Japan as Okami.

In fact, in Britain during the Second World War there were trials in Scottish sea lochs to determine whether large static nets could harvest sufficient plankton to supplement the national diet should food become scarce. While those early Scottish trials in the 1940s proved unsuccessful, today, a commercial copepodcopepods A group of small crustaceans found in the sea and nearly every fresh water habitat. Some species are planktonic (drifting in sea waters), some are benthic (living on the ocean floor), and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests, bogs, springs, ephemeral ponds and puddles, damp moss, or water-filled recesses (phytotelmata) of plants such as bromeliads and pitcher plants. Many live underground in marine and freshwater caves, sinkholes, or stream beds. Copepods are sometimes used as biodiversity indicators. harvest for food for aquaculture occurs in some Norwegian Fjords by using large nets towed by trawlers.

The author and plankton scientist : Dr Richard Kirby

The author and plankton scientist : Dr Richard Kirby

Now, we need to pay attention to the plankton more than ever. Living at the sea surface the plankton are particularly sensitive to changes in sea surface temperature, which is influenced by the air temperature above. (We often forget that we can engineer our thermal environment unlike other life on Earth that lives where the temperature suits it best.)

My research and that of other plankton scientists, is revealing that rising sea temperatures due to current climate change are altering the abundance, distribution, and seasonality of the plankton throughout the oceans with ensuing ramifications for the marine food chain, our commercial fisheries, and the wider marine ecosystem.”

Unfortunately, in this short blog there wasn’t time to tell you how the plankton do so much more than just support the marine food web. However, you can find out how much more by watching my short film Ocean Drifters, a secret world beneath the waves, narrated by David Attenborough:

 

Ocean Drifters from Plymouth University on Vimeo.
If you have any problems viewing the video on this website, click the Ocean Drifters link above.

 

Dr Richard Kirby is a British plankton expert, scientist, author and speaker. Follow Richard @planktonpundit on Twitter. You can see more images of plankton and learn more about them in Dr Richard Kirby’s book “Ocean Drifters, a secret world beneath the waves” available on Amazon and as an iBook.

Source: Blue Planet Society, March 2015. For further details, see http://blueplanetsociety.blogspot.co.uk/2015/03/the-importance-of-plankton.html


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