Tropical Region


Also found in: Dictionary, Thesaurus.

Tropical Region

 

a zoogeographic region of the world ocean that encompasses the tropical and subtropical zones, where the water temperature at the surface does not fall below 20°C. In the west the tropical region’s boundaries are situated at approximately 35° N and S lat., while in the east they are somewhat closer to the equator.

In the pelagic zone of the tropical region there are many sharks, tuna, sailfish, flying fish, and sea turtles. In the benthic zone there are coral reefs, with their characteristic communities, as well as coastal mangrove thickets and abundant crabs, spiny lobsters, and large gastropods and bivalves. In the pelagic zone, circumtropical species predominate over species found only in certain sectors. Therefore, the tropical region is uniform, but various parts of it are identified as provinces (Atlantic, Indo-West-Pacific, and East Pacific).

In the benthic zone—the littoral and the shelf—there are very few circumtropical species, and the tropical region is considered a realm, or superregion, which is broken down into four (sometimes three or five) regions: Indo-West-Pacific, Central American (which is sometimes divided into the West Atlantic and East Pacific), West African, and Mediterranean-Lusitanian (the last two are sometimes joined to form the East Atlantic). The regions identified by benthic fauna are separated by zoogeographic barriers (the land barriers of the continents of the New World and Old World and the ocean barriers of the Middle Atlantic and East Pacific). Less than 10 percent of the species of the fauna of neighboring regions penetrate these barriers, as the shelf fauna cannot cross the bottom of the ocean, whose length also exceeds the migration capability of the pelagic larvae of benthic animals.

The fauna of the Indo-West-Pacific region is the richest and most ancient. It is highly endemic and was apparently the original group for most of the groups of shelf fauna. The West Atlantic fauna is second in wealth and diversity of species. The East Pacific fauna is significantly poorer, and the East Atlantic fauna, containing many species of West Atlantic origin, is still poorer.

In the Central American region numerous unique genera are found in the shallow tropical waters of both the East Pacific and West Atlantic parts; crabs, sea urchins, and certain fishes are represented by different but closely related species. Such distribution developed because a strait existed in what is now Central America from the Miocene to Lower Pliocene. This region is sometimes divided into two independent regions on the basis of these differences. The fauna of the eastern tropical region is poorer as a result of sharp climatic changes of the Pleistocene that were slightly reflected in the western parts.

K. N. NESIS

References in periodicals archive ?
This will benefit communities not only in Northern Australia but also throughout other tropical regions, which now account for 40 per cent of the global population.
Like Zapata, Holbik sees an increase in demand for tropical roots from both immigrant communities that originate from tropical regions and increasingly health-conscious Americans of other ethnic backgrounds.
The company said the 2Ku antenna produces more bandwidth at a lower cost, resulting in significant performance improvement, particularly in tropical regions where restrictions associated with operating at high skew angles degrade satellite solutions.
Biodiversity is declining in both temperate and tropical regions, but the decline is greater in the tropics, the World Wide Fund for Nature report indicates.
In tropical regions, plant-eating fish perform the vital role of keeping reefs free of large seaweeds, allowing corals to flourish,' said the study's lead author, Adriana Verges of the University of New South Wales.
The collection draws great inspiration from the natural surroundings of the tropical regions.
He discusses assessing the effluent quality, the biosorption of Cu(II) onto agricultural materials from tropical regions, cyclic sorption and desorption of Cu(II) onto coconut shell and iron oxide coated sand, modeling the kinetics of Cu(II) bisorption onto coconut shell and Morina oleifera seeds from tropical regions, removing Cu(II) by biosorption onto coconut shell in fixed-bed column systems, and treating gold mining effluence in pilot fixed bed sorption systems.
Plantations and secondary forests are becoming the dominant forest ecosystems worldwide, particularly in tropical regions where deforestation has reduced primary forest cover.
This was the warning of South Korean cycling official Edward Sung Woong Park who said recently that the chilly condition in Korea during the months of September and October is colder than what the Philippines have in Baguio so countries in tropical regions will be in for a tough grind.
Because temperatures fluctuate more widely near the poles, these regions will take longer and require more of a temperature boost to depart from historical ranges than tropical regions will.
The Stevia plant is indigenous to the tropical regions of Central and South America and has been used as a natural sweetener for centuries by the Guarani people of Paraguay.
Due to lack of reliable performance analysis in tropical regions [1-3] and to identify the effects of these impairments on the signal quality level in terms of packet error rate (PER), this paper presents a newly developed error rate software (ERS) extension to improve the satellite/Earth station quality performance assessment and analyzes regarding the effects of the above mentioned parameters.

Full browser ?