| 释义 |
pelagic, a.|pɪˈlædʒɪk|
[ad. L. pelagic-us, a. Gr. *πελαγικός, f. πέλαγ-ος the sea.]
a. Of or pertaining to the open or high sea, as distinguished from the shallow water near the coast; oceanic; now spec. living on or near the surface of the open sea or ocean, as distinguished from its depths. Also applied spec. to the environment in any part of the sea away from the littoral and benthic regions and to marine life at any depth that is independent of these regions.
1656Blount Glossogr., Pelagick, of the Sea, or that liveth in the Sea. 1802Bingley Anim. Biog. (1813) III. 420 The Pelagic Nereis. 1832Lyell Princ. Geol. II. 280 Littoral and estuary shells are more frequently liable..to be intermixed with the exuviæ of pelagic tribes. 1843Rep. Brit. Assoc. 13 Seamen are..well acquainted with the general forms of the pelagic fish. 1865Gosse Land & Sea (1874) 150 The pelagic shells, or those which during life rove freely through the sea. 1882Nature XXVI. 559 Used technically by naturalists, the term Pelagic applied to living things, denotes those animals and plants which inhabit the surface waters of the seas and oceans. Ibid., I have spoken of pelagic life as belonging to the surface waters of the ocean..; but,..it is impossible as yet to limit definitely the range of pelagic forms in depth, and we shall even have to refer to some connections of the fauna of the deep ocean bottom with that of the surface. Pelagic life then includes the inhabitants of the whole ocean waters, excluding those belonging to the bottom and shores. 1891Murray & Renard in Rep. Sci. Results Voy. H.M.S. Challenger: Deep-Sea Deposits iv. 251 We would suggest that the term oceanic Plankton be subdivided into pelagic Plankton for the animals living in the waters from the surface to 100 fathoms, zonary Plankton for those living in the intermediate zones between 100 fathoms from the surface and 100 fathoms from the bottom,..and abyssal Plankton for those living within 100 fathoms from the bottom over pelagic deposits. 1912Murray & Hjort Depths of Ocean ix. 562 The conception of a ‘pelagic’ mode of life, originally associated with the animal-life of the ocean-surface, thus gradually proved to hold true for life in mid-water also... The main characteristic of pelagic life is its independence of the bottom. 1954N. B. Marshall Aspects Deep Sea Biol. v. 89 Swimming and floating between the surface and the deep-sea floor are the pelagic animals. 1957Mem. Geol. Soc. Amer. No. 67. I. xxii. 643 The distinction between pelagic and benthic species in these depths is difficult in many cases and depends on how far from the bottom a species must live in order to be considered pelagic. Ibid. 645 As yet nothing is known about pelagic animals from depths greater than 6000 meters—i.e., from the trenches. Ibid. II. vi. 97 The subdivision of the water above the bottom, the great pelagic region, is more satisfactorily established. 1962K. F. Lagler et. al. Ichthyol. xiv. 468 Marine fishes may be classed into three main categories: (a) the shore or shelf fauna..; (b) the pelagic or open sea fishes, generally living near the surface of tropical and warm-temperature seas..; (c) deepsea or abyssal forms, inhabiting depths greater than 100 fathoms. 1969[see nekton]. 1970D. A. Ross Introd. Oceanogr. vi. 140 The pelagic realm can be subdivided into the neritic environment (the water that overlies the continental shelf) and the oceanic environment (the water of the deep sea). 1974[see neritic a.].
b. Of sealing or whaling: Carried on or performed on the high seas. So pelagic sealer, pelagic whaler.
1891Blackw. Mag. Oct. 609 ‘Pelagic’ sealing as at present carried on, cannot long be continued. 1897Daily News 27 Jan. 6/6 The Commission was sent out in consequence of the statements made by the United States and Russia that the seal herd was being wiped out by pelagic sealing. 1901Munsey's Mag. (U.S.) XXV. 358/1 The pelagic sealers kill the animals with guns, spears, or any effective weapon while they are in the water. 1941J. S. Huxley Uniqueness of Man viii. 184 With the advent of pelagic whaling it seemed certain that, unless international regulation of the industry were achieved, whales would certainly become exceedingly scarce, and some species might be wiped out. 1958Times 12 Nov. 11/6 The total number of whales caught last year by pelagic or factory ship expeditions in the Antarctic in 69 catching days was 35,977. 1974Nature 4 Oct. 367/2 If the 1974–75 quotas for pelagic whaling in the Southern hemisphere are reached..the catch of all species next season may reach 380 thousand tons.
c. Of sea-bed material: formed within the sea itself, rather than transported from the land.
1884Murray & Renard in Proc. R. Soc. Edin. XII. 515 The following table shows the nomenclature we have adopted:—Terrigenous deposits... Pelagic deposits. 1891― Rep. Deep-Sea Deposits iii. 185 From the point of view of their composition, as well as of their geographical and bathymetrical position, Marine Deposits may be separated into two great divisions, viz. (I.) Pelagic Deposits—those formed towards the centres of the great oceans, and made up chiefly of the remains of pelagic organisms along with the ultimate products arising from the decomposition of rocks and minerals; and (II.) Terrigenous Deposits. 1959A. Hardy Fish & Fisheries v. 103 Pelagic deposits..cover the floor of the great oceans in the depths beyond the edge of the shelf. 1970D. A. Ross Introd. Oceanogr. viii. 297 Deep-sea sediments can be divided into two major groups: pelagic sediments and terrigenous sediments.
d. = limnetic a.
1899G. C. Whipple Microsc. Drinking-Water viii. 105 The plants and animals that inhabit lakes and ponds may be classified according to their habitat... The limnetic or pelagic organisms are those that make their home in the open water. 1955C. C. Davis Marine & Fresh-Water Plankton i. 11 Lakes may be subdivided into horizontal and vertical portions. Horizontally, the relatively shallow area close to shore..is called the littoral region, while the region of open water is known as the limnetic (or pelagic) region. 1975G. A. Cole Textbk. Limnol. ii. 9/1 Beyond the pond weeds..is the open water. This is the limnetic or pelagic zone, a region in the lake where shore and bottom have lessened influence.
e. Of birds: inhabiting regions of open sea beyond the edges of a continental shelf, feeding on plankton and other marine organisms, and returning to shore only in the breeding season.
1935V. C. Wynne-Edwards in Proc. Boston Soc. Nat. Hist. XL. 240 The typical species of these three communities [of birds] in the temperate North Atlantic might be separated as follows: 1. Inshore... 2. Offshore... 3. Pelagic. Ibid. 241 Pelagic birds..feed chiefly on plankton. 1936R. C. Murphy Oceanic Birds S. Amer. I. ii. 323 South America..is the longest mass of land lying in the relatively open oceans of the southern hemisphere... It is natural..that nearly all the genera, and a large proportion of the species of southern-hemisphere pelagic birds should occur within the limits of the field. 1954Fisher & Lockley Sea-Birds vii. 170 Little is known of the construction of pelagic flocks. 1974A. Dillard Pilgrim at Tinker Creek x. 165 The oceanic breeding grounds of pelagic birds are as teeming and cluttered as any human Calcutta. |