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Food chain in a Swedish lake. Osprey feed on northern pike, which in turn feed on perch which eat bleak which eat crustaceans.. A food chain is a linear network of links in a food web, often starting with an autotroph (such as grass or algae), also called a producer, and typically ending at an apex predator (such as grizzly bears or killer whales), detritivore (such as earthworms and woodlice ...
Declines in the duration and extent of sea ice in the Arctic leads to declines in the abundance of ice algae, which thrive in nutrient-rich pockets in the ice. These algae are eaten by zooplankton, which are in turn eaten by Arctic cod, an important food source for many marine mammals, including seals. Seals are eaten by polar bears.
Marine algae can be divided into six groups: green, red and brown algae, euglenophytes, dinoflagellates and diatoms. Dinoflagellates and diatoms are important components of marine algae and have their own sections below. Euglenophytes are a phylum of unicellular flagellates with only a few marine members. Not all algae are microscopic.
A type of algae, Ancylonema nordenskioeldii, was found in Greenland in areas known as the 'Dark Zone', which caused an increase in the rate of melting ice sheet. [89] The same algae was found in the Italian Alps, after pink ice appeared on parts of the Presena glacier. [90] The various sorts of algae play significant roles in aquatic ecology.
The rotary motor model used by bacteria uses the protons of an electrochemical gradient in order to move their flagella. Torque in the flagella of bacteria is created by particles that conduct protons around the base of the flagellum. The direction of rotation of the flagella in bacteria comes from the occupancy of the proton channels along the ...
Cosmarium is a large genus of desmids (Desmidiaceae), a group of green algae closely related to the land plants (Embryophyta). [1] [2] Members of this genus are microscopic and found in freshwater habitats around the world. [3] The name Cosmarium comes from the Greek word κοσμάριον - kosmarion, meaning a small ornament. [4]
In a reversal of the pattern on land, in the oceans, almost all photosynthesis is performed by algae and cyanobacteria, with a small fraction contributed by vascular plants and other groups. Algae encompass a diverse range of organisms, ranging from single floating cells to attached seaweeds. They include photoautotrophs from a variety of groups.
Micrasterias is a unicellular green alga of the order Desmidiales.Its species vary in size reaching up to hundreds of microns. Micrasterias displays a bilateral symmetry, with two mirror image semi-cells joined by a narrow isthmus containing the nucleus of the organism.