marine biology


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

marine biology,

study of ocean plants and animals and their ecological relationships. Marine organisms may be classified (according to their mode of life) as nektonic, planktonic, or benthic. Nektonic animals are those that swim and migrate freely, e.g., adult fishesfish,
limbless aquatic vertebrate animal with fins and internal gills. Traditionally the living fish have been divided into three class: the primitive jawless fishes, or Agnatha; the cartilaginous (sharklike) fishes, or Chondrichthyes; and the bony fishes, or Osteichthyes.
..... Click the link for more information.
, whaleswhale,
aquatic mammal of the order Cetacea, found in all oceans of the world. Members of this order vary greatly in size and include the largest animals that have ever lived. Cetaceans never leave the water, even to give birth.
..... Click the link for more information.
, and squidsquid,
carnivorous marine cephalopod mollusk. The squid is one of the most highly developed invertebrates, well adapted to its active, predatory life. The characteristic molluscan shell is reduced to a horny plate shaped like a quill pen and buried under the mantle.
..... Click the link for more information.
. Planktonic organisms, usually very small or microscopic, have little or no power of locomotion and merely drift or float in the water. Benthic organisms live on the sea bottom and include sessile forms (e.g., spongessponge,
common name for members of the aquatic animal phylum Porifera, and for the dried, processed skeletons of certain species used to hold water. Over 4,500 living species are known; they are found throughout the world, especially in shallow temperate waters.
..... Click the link for more information.
, oystersoyster,
bivalve mollusk found in beds in shallow, warm waters of all oceans. The shell is made up of two valves, the upper one flat and the lower convex, with variable outlines and a rough outer surface.
..... Click the link for more information.
, and coralscoral,
small, sedentary marine animal, related to the sea anemone but characterized by a skeleton of horny or calcareous material. The skeleton itself is also called coral.
..... Click the link for more information.
), creeping organisms (e.g., crabscrab,
crustacean with an enlarged cephalothorax covered by a broad, flat shell called the carapace. Extending from the cephalothorax are the various appendages: five pairs of legs, the first pair bearing claws (or pincers), are attached at the sides; two eyes on short, movable
..... Click the link for more information.
 and snailssnail,
name commonly used for a gastropod mollusk with a shell. Included in the thousands of species are terrestrial, freshwater, and marine forms. Some eat both plant and animal matter; others eat only one type of food.
..... Click the link for more information.
), and burrowing animals (e.g., many clamsclam,
common name for certain bivalve mollusks, especially for marine species that live buried in mud or sand and have valves (the two pieces of the shell) of equal size.
..... Click the link for more information.
 and wormsworm,
common name for various unrelated invertebrate animals with soft, often long and slender bodies. Members of the phylum Platyhelminthes, or the flatworms, are the most primitive; they are generally small and flat-bodied and include the free-living planarians (of the class
..... Click the link for more information.
). Seafloor areas called hydrothermal ventshydrothermal vent,
crack along a rift or ridge in the deep ocean floor that spews out water heated to high temperatures by the magma under the earth's crust. Some vents are in areas of seafloor spreading, and in some locations water temperatures above 350°C; (660°F;) have
..... Click the link for more information.
, with giant tube worms and many other unusual life forms, have been intensively studied by marine biologists in recent years.

The distribution of marine organisms depends on the chemical and physical properties of seawater (temperature, salinity, and dissolved nutrients), on ocean currents (which carry oxygen to subsurface waters and disperse nutrients, wastes, spores, eggs, larvae, and plankton), and on penetration of light. Photosynthetic organisms (plants, algae, and cyanobacteria), the primary sources of food, exist only in the photic, or euphotic, zone (to a depth of about 300 ft/90 m), where light is sufficient for photosynthesisphotosynthesis
, process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the presence of chlorophyll. Some of the plants that lack chlorophyll, e.g.
..... Click the link for more information.
. Since only about 2% of the ocean floor lies in the photic zone, photosynthetic organisms in the benthos are far less abundant than photosynthetic plankton (phytoplankton), which is distributed near the surface oceanwide. Very abundant phytoplankton include the diatomsdiatom
, unicellular organism of the kingdom Protista, characterized by a silica shell of often intricate and beautiful sculpturing. Most diatoms exist singly, although some join to form colonies.
..... Click the link for more information.
 and dinoflagellates (see Dinoflagellatadinoflagellata
, phylum (division) of unicellular, mostly marine algae, called dinoflagellates. In some classification systems this division is called Pyrrhophyta. There are approximately 2,000 species of dinoflagellates.
..... Click the link for more information.
). Heterotrophic plankton (zooplankton) include such protozoansprotozoan
, informal term for the unicellular heterotrophs of the kingdom Protista. Protozoans comprise a large, diverse assortment of microscopic or near-microscopic organisms that live as single cells or in simple colonies and that show no differentiation into tissues.
..... Click the link for more information.
 as the foraminiferansforaminiferan
, common name for members of the class Foraminifera, large, shelled ameboid protozoans belonging to the phylum Sarcodina. Most foraminiferan shells are calcareous, but some are siliceous, and others are built of sand grains.
..... Click the link for more information.
; they are found at all depths but are more numerous near the surface. Bacteriabacteria
[pl. of bacterium], microscopic unicellular prokaryotic organisms characterized by the lack of a membrane-bound nucleus and membrane-bound organelles. Once considered a part of the plant kingdom, bacteria were eventually placed in a separate kingdom, Monera.
..... Click the link for more information.
 are abundant in upper waters and in bottom deposits.

The scientific study of marine biology dates from the early 19th cent. and now includes laboratory study of organisms for their usefulness to humans and the effects of human activity on marine environments. Important marine biological laboratories include those at Naples, Italy; at Plymouth and Millport in England; and at Woods Hole, Mass., La Jolla, Calif., and Coral Gables, Fla. Research has been furthered by unmanned and manned craft, such as the submersiblesubmersible,
small, mobile undersea research vessel capable of functioning in the ocean depths. Development of a great variety of submersibles during the later 1950s and 1960s came about as a result of improved technology and in response to a demonstrated need for the capability
..... Click the link for more information.
 Alvin.

See also oceanographyoceanography,
study of the seas and oceans. The major divisions of oceanography include the geological study of the ocean floor (see plate tectonics) and features; physical oceanography, which is concerned with the physical attributes of the ocean water, such as currents and
..... Click the link for more information.
.

Bibliography

See R. Carson, The Sea Around Us (rev. ed. 1961); R. Ballard, Exploring Our Living Planet (1983); M. Banks, Ocean Wildlife (1989); W. J. Broad, The Universe Below (1997).

marine biology

[mə′rēn bī′äl·ə·jē]
(biology)
A branch of biology that deals with those living organisms which inhabit the sea.
References in periodicals archive ?
Sam's interest in marine biology began at the age of six and his entrepreneurial nature developed during his teenage years, when he set up his first business providing pond maintenance services at the age of 17.
The new marine biology shack will also include a large wet lab to support the team's ongoing research efforts, and will host visiting researchers and academics from across the globe.
Domeier also shared that there was a time when Paul called him and said that he'd like to quit acting to go back to school and study Marine Biology.
The 'Fast and Furious' actor had studied marine biology in college and had also got to live out a life-long dream for National Geographic's Expedition Great White, where he spent days as part of a crew catching and tagging Great White sharks off the coast of Mexico, ABC reported.
Studies of Marine Biology in Brazil seem to be more important than ever.
The Conference will schedule and coordinate all meetings with their Editorial Board Members and other experts in the Aquatic & Marine Biology field across the world.
Finally, the Marine Biology Department of the Estonian Marine Institute has strong traditions in Natural History writing.
The 30 students onboard studying marine biology, engineering and leadership flew home on Saturday, with another 30 Swedish students arriving in Liverpool to take their place.
The talk, sponsored by the Eugene Natural History Society, will be given by Jan Hodder, academic coordinator and instructor at the Oregon Institute of Marine Biology in Coos Bay.
Modern day explorer, Paul has had to endure being run over by an iceberg the size of Hyde Park, has also climbed into Antarctica's most active volcano to assist NASA in testing its Mars lander, he has dived into sub-zero waters to find marine biology and has also had to survive for four days by eating only soup made out of toothpaste.
The rare white otter and her four-monthold pup were snapped by retired marine biology teacher Brian Maxwell, 69, in California.

Full browser ?