phytoplankton


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

Phytoplankton

Mostly autotrophic microscopic algae which inhabit the illuminated surface waters of the sea, estuaries, lakes, and ponds. Many are motile. Some perform diel (diurnal) vertical migrations, others do not. Some nonmotile forms regulate their buoyancy. However, their locomotor abilities are limited, and they are largely transported by horizontal and vertical water motions.

A great variety of algae make up the phytoplankton. Diatoms (class Bacillariophyceae) are often conspicuous members of marine, estuarine, and fresh-water plankton. Dinoflagellates (class Dinophyceae) occur in both marine and fresh-water environments and are important primary producers in marine and estuarine environments. Coccolithophorids (class Haptophyceae) are also marine primary producers of some importance. They do not occur in fresh water.

Even though marine and fresh-water phytoplankton communities contain a number of algal classes in common, phytoplankton samples from these two environments will appear quite different. These habitats support different genera and species and groups of higher rank in these classes. Furthermore, fresh-water plankton contains algae belonging to additional algal classes either absent or rarely common in open ocean environments. These include the green algae (class Chlorophyceae), the euglenoid flagellates (class Euglenophyceae), and members of the Prasinophyceae.

The phytoplankton in aquatic environments which have not been too drastically affected by human activity exhibit rather regular and predictable seasonal cycles. Coastal upwelling and divergences, zones where deeper water rises to the surface, are examples of naturally occurring phenomena which enrich the mixed layer with needed nutrients and greatly increase phytoplankton production. In the ocean these are the sites of the world's most productive fisheries.

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.

phytoplankton

[¦fīd·ə′plaŋk·tən]
(ecology)
Planktonic plant life.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Table II.- Phytoplankton cell abundance (Cells/L) and their percent (%) contribution during fish killing incident of Al-Arbain and Al-Shams lagoons at Jeddah coast, Saudi Arabia, the Red Sea.
"We Googled what is that we were looking at and they seemed to be naturally occurring bioluminescent phytoplankton that are harmless," Sohail said.
In the surface waters of the modern oceans, light zinc isotopes are generally preferred by phytoplankton. (6) This results in the removal of light zinc isotopes from the surface by phytoplankton, leaving the residual seawater enriched in heavier zinc isotopes.
Some phytoplankton grow better where vertical motion along fronts is relatively fast and, consequently, nutrient supplies are larger.
Water transparency (Secchi depth, SD) was measured and hydrochemical as well as phytoplankton samples were collected monthly during the growing season in 1997-2015.
A team of specialists from MOCCAE has been collecting and analyzing water samples from various coastal areas of the Arabian Sea and the Gulf of Oman to identify the types of phytoplankton present.
Since plants and phytoplankton both reduce the net carbon in the atmosphere, studying them and predicting their future has direct implications for where the Earth is headed in a time when human activity is adding carbon to the atmosphere at an unprecedented rate.
Different levels of disturbance affect community organization in various ways (Lopes, Ferragut, & Bicudo, 2009) and may interrupt, postpone, or redirect seasonal phytoplankton successions (Znachor, Zapomelova, Rehakova, Nedoma, & Simek, 2008).
Freshwater shrimps play an important role in the recycling of nutrients in the aquatic ecosystem especially in the processing of detritus, aquatic insects, polychaetes, other crustaceans, fish, mollusks and zooplankton, fragments of aquatic plants, planktonic algae and diatoms, and phytoplankton [1].
In the future, the shell-making phytoplankton "may calcify even less than we assume today based on short-term experiments."
Studies have shown that phytoplankton species are very sensitive to physical and chemical changes in stream ecosystems, including findings indicating that the composition of the phytoplankton responds to different human impacts on temperate rivers (Leland, 2003; Abonyi et al., 2012).