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This is an accepted version of this page This is the latest accepted revision, reviewed on 24 November 2024. Organisms living in water or air that are drifters on the current or wind This article is about the marine organisms. For other uses, see Plankton (disambiguation). Marine microplankton and mesoplankton Part of the contents of one dip of a hand net. The image contains diverse planktonic ...
Phytoplankton obtain their energy through photosynthesis, as trees and other plants do on land. This means phytoplankton must have light from the sun, so they live in the well-lit surface layers (euphotic zone) of oceans and lakes. In comparison with terrestrial plants, phytoplankton are distributed over a larger surface area, are exposed to ...
Zooplankton feed on bacterioplankton, phytoplankton, other zooplankton (sometimes cannibalistically), detritus (or marine snow) and even nektonic organisms. As a result, zooplankton are primarily found in surface waters where food resources (phytoplankton or other zooplankton) are abundant. Zooplankton can also act as a disease reservoir.
Some of the largest plankton are krill and feed the largest of animals, baleen whales. My first foray into the scientific world was a job sexing Jassa falcata (a tiny amphipod) under a microscope.
Reproduction among these organisms is asexual by binary fission, during which the diatom divides into two parts, producing two "new" diatoms with identical genes. Each new organism receives one of the two frustules – one larger, the other smaller – possessed by the parent, which is now called the epitheca ; and is used to construct a second ...
The alternation of generations allows for a fast generation time, with both solitary individuals and aggregate chains living and feeding together in the sea. When phytoplankton is abundant, this rapid reproduction leads to fairly short-lived blooms of salps, which eventually filter out most of the phytoplankton.
Phytoplankton are then consumed by krill and small zooplankton grazers, which in turn are preyed upon by higher trophic levels. Any unconsumed phytoplankton form aggregates, and along with zooplankton faecal pellets, sink rapidly and are exported out of the mixed layer (< 12 Gt C yr−1 14).
Algae that are carried passively by water are plankton, specifically phytoplankton. Algae constitute a polyphyletic group [4] since they do not include a common ancestor, and although their chlorophyll-bearing plastids seem to have a single origin (from symbiogenesis with cyanobacteria), [5] they were acquired in