Glossary of pelagic biogeography r. K. Johnson†, B. J. Zahuranec*, D. Boltovskoy and A. C. Pierrot-Bults
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inverse estuary See negative estuary (cf estuary). inverted pyramid pirámide invertida Ecology: A situation where a rapid rate of turnover allows a small biomass of prey to support a larger biomass of predators with a slower turnover. Not uncommon in aquatic systems where primary producers (phytoplankton) are small and divide rapidly whereas zooplanktonic herbivores are larger and longer-lived (cf ecological pyramid). irruption irrupción Sudden change or oscillation in the population density of an organism, often a rapid growth of population size followed by a crash.
A quantitative approach to ecological biogeography (qv) based on an empirically determined and mathematically modeled relationship between island area, distance of island from mainland species source areas, and equilibrium species richness. The equilibrium is ultimately a balance between immigration and extinction. Applies to “habitat islands” as well as to geographic islands. island effect efecto de isla Putative occurrence of large concentrations of meso- and bathypelagic organisms around island chains and submerged ridges in otherwise oligotrophic oceanic areas, reflecting the relatively higher productivity around these surface and subsurface features.
Line (isopleth) of equal pressure. Contours of isobaric surfaces are commonly drawn in weather charts to forecast winds and in oceanography to calculate geostrophic flow.
Line (isopleth) of equal depth, commonly used to represent depth contours on a chart of subsurface features.
See isozyme. isolating mechanism(s) 1. Definition mecanismo de aislamiento 1. Definición A property (ies) of individuals that prevents successful interbreeding or reproduction with individuals that belong to different populations (prezygotic vs postzygotic isolating mechanisms). isolating mechanism(s) 2. Categories. mecanismo de aislamiento. 2. Categorías Premating (extrinsic): ecogeographical, habitat, seasonal, ethological, mechanical Postmating (intrinsic): gametic, developmental, hybrid inviability, hybrid sterility, selective hybrid elimination. isolation aislamiento Evolution: Separation of two populations so that they are prevented from interbreeding, whether by extrinsic (premating) or intrinsic (postmating) mechanisms.
Line (isopleth) of equal light intensity. isometry isometría Growth in which the relative proportions of body parts remain constant with change in total body size. (cf allometry).
A line on a chart or map connecting points of equal abundance of a species. isoosmotic (isosmotic) isoosmótico Isotonic; having the same osmotic pressure (cf hypoosmotic, hyperosmotic). isophene isofena (1) A line on a chart or map connecting points having the same frequency of occurrence of a given phenotype; phenocontour. (2) A line on a chart or map connecting points at which seasonal events occur on the same date; isochronal line. isopleth isopleta A line connecting equivalent values of physical, chemical or biological parameters, commonly used to contruct contour charts.
Line (isopleth) of equal density. isostasy isostasis Concept that large masses of the earth's crust tend toward a "floating" equilibrium and that changes in the mass/position of one block will be compensated for by the uplifting or sinking of other blocks.
Line (isopleth) of equal temperature. isozyme isozima Form of enzyme that exists in two or more structural forms easily separable and identifiable by electrophoretic methods. Widely used in studies of allelic frequency variation in populations (cf allozyme). ITCZ See Intertropical Convergence Zone. iteroparity iteroparidad Situation in which a given individual normally reproduces more than once in its reproductive lifetime (cf semelparity).
Oceanography, meteorology: Directed, concentrated, high-speed flow of water or air, such as the jet streams in the atmosphere or currents such as the Somali Current during peak Southwest Monsoon. jetsam Floating debris at sea surface or washed ashore, deliberately cast off from a vessel at sea (cf flotsam). Jordan's laws ley de Jordan, regla de Jordan (1) Observation that the closest relatives of a species are found immediately adjacent to it but isolated from it by a geographical barrier. (2) Observation that individuals of a given fish species develop more vertebrae in a cold climate than in a warm one (temperature during a critical phase of developmental determination appears to be controlling; true in general of serial meristic (qv) character values). K-selection K-seleccción Selection for maximizing competitive ability, the "strategy" of equilibrium species, typically a response to stable and/or predictable environmental resources. Associated features: low fecundity, high juvenile survivorship, high parental investment per individual offspring, late maturity. keystone predator predador clave A predator (qv) whose activities tend to maintain higher community diversity than would be true if the predator were absent. Predation is viewed as reducing competition between two or more target species below the point where competitive exclusion (qv) takes place. kin selection ortoselección Form of natural selection in which the "altruism" of an individual benefits its own close relatives and thereby helps to ensure the survival of at least some of its own genes.
nudo Unit of velocity equal to one nautical mile per hour (0.515 m/sec). kollaplankton Plankton (qv) rendered buoyant by encasement in gelatinous envelopes; also spelled collaplankton.
Euphausiid crustaceans occurring in dense swarms, especially Euphausia superba of the Southern Ocean, a principal food source for many Southern Ocean fishes, sea birds, and marine mammals. kurtosis curtosis Statistics: One measure of departure of a frequency distribution from a normal distribution, quantified in terms of relative peakedness (leptokurtic) or flatness (platykurtic) (cf skewness). L labile lábil Plastic; readily modified. lacustrine lacustre Pertaining to or living in lakes or ponds (cf lentic). lagoon albufera, laguna costera Coastal body of shallow water characterized by a restricted connection with the sea or lake. Lagrangian measurement medición lagrangeana Measurement of currents in which the path followed by each fluid particle is traced as a function of time (cf Eulerian measurement). Classic methods of Lagrangian measurement include passive drifters such as buoys, drogues or dye release (not to mention messages in bottles). land bridge conexión terrestre Connection between two land masses, especially continents, forming a migrational corridor (qv). Before the widespread acceptance of continental drift, putative existence of former land bridges was invoked to explain faunal and floral similarities of now disjunct land areas. Langmuir circulation circulación de Langmuir, células de Langmuir A surface system of vortices and antivortices resulting in lines or zones of upwelling and downwelling, divergences and convergences, often expressed at the surface in so-called drift lines. Set up by light but steady winds, a major source of near surface plankton patchiness. latiphenic latifénico See monomorphic. latitudinal diversity gradient gradiente latitudinal de diversidad The trend, widespread but not universal among groups of plants and animals, of exhibiting a monotonic increase in diversity when passing from polar regions toward the equator. Laurasia The northern supercontinent formed by the breakup of Pangaea in the Mesozoic (ca 150 million years B. P.), and comprising North America, Greenland, Europe, and Asia excluding India (cf Gondwanaland). law of the minimum ley del mínimo Principle that productivity of an autotroph is determined by the availability of the scarcest required nutrient, such that different nutrients may be limiting depending upon the specific needs of the autotroph and the availability of all other requisite nutrients. More correctly, Liebig's law of the minimum. league An archaic unit of distance, equal to about 3 nautical miles. lecithotrophic lecitotrófico Pertaining to developmental stages that depend upon eggs rich in yolk. lectotype lectotipo Taxonomy: One of a series of syntypes (qv) which, subsequent to the publication of the original description (of a species), is selected and designated to serve as the "type" ("name-bearing") specimen. leeward barlovento Pertaining to the side facing away from a wind or water current. lentic léntico, lenítico Applied to a freshwater habitat characterized by calm or standing water, eg ponds, lakes, swamps and bogs (cf lotic, lacustrine).
Large organic molecules or aggregates of colloidal proportions suspended in water. leptophenic leptofénico See monophormic. Liebig's law of the minimum ley del mínimo de Liebig See law of the minimum. life cycle ciclo de vida Ecology: Series of developmental changes undergone by individuals comprising a population including fertilization, reproduction, death, and replacement. The life "cycle" is linear with respect to individuals but cyclical with respect to populations. life history strategy estrategia del ciclo vital The complex interreactions between life (qv) cycles and environments that allow the individual (and therefore the species) to survive and reproduce.
Inhabiting mud. limiting factor factor limitante Ecology: In the sense of the law of the minimum (qv), that factor which limits a population, especially used in application to that factor limiting phytoplankton growth under stated conditions. limivorous iliófago Feeding on mud; limophagous. limnetic zone zona limnética The area in deeper and/or more extensive freshwater ecosystems that lies above the compensation depth but beyond the littoral zone. The limnetic and littoral zones together comprise the euphotic zone. limnium limnobios A lake community. limnodic Pertaining to salt marshes. limnodium limnodio A salt marsh community. limnology limnología The study of freshwater ecosystems, especially lakes. limophagous iliófago Feeding on mud; limivorous. linkage ligamiento (1) The dependency of one function or event upon the occurrence of another event or function. (2) Genetics: Association of genes on the same chromosome.
Pertaining to organisms that erode or bore into rock (cf endolithic). littoral litoral Ecology: In marine systems the shoreline or intertidal zone. In lakes and shallow freshwater ecosystems the zone where light penetration to the bottom allows the growth of rooted plants.
The landward edge of the littoral (qv) zone.
Genetics: Specific place on a chromosome where a gene is located. At each locus is one gene, which, if it can occur in several different forms (alleles), is represented at a given locus by only one of those alleles (qv).
A model of population growth explicitly stated as dN/dt = rN ((K-N)/K) where N is the number of individuals at time t, r is the intrinsic rate of population increase (here a constant, independent of N, as in the exponential model (qv)), and K is a special and limiting value of N, the so-called carrying capacity of the environment at which dN/dt=0. longevity longevidad (1) Biology: The life span (duration, persistence) of an individual. (2) Paleontology: Applied to the persistence of a taxon, species, genus, family, over time.
Referring to currents or movement parallel to the coastline. lotic lótico Referring to a freshwater habitat characterized by running water, eg springs, streams, and rivers (cf fluvial, rhithron, lentic).
Based on the logistic model (qv), simple equations predicting results of predator-prey interaction in two-species competition.
Light-producing, bioluminescent. luminescence luminiscencia Production of light. Biological luminescence (bioluminescence) involves chemical reactions (luciferin, luciferase) to produce light by living organisms. Bioluminescence has evolved independently in a variety of organisms. luticolous lutícola Inhabiting mud. M macroevolution macroevolución Evolution (qv) above the species level, the development of new higher taxa, genera, families, orders, etc.
An inorganic or organic nutrient compound or element needed in relatively large amounts for autotrophic productivity. Nitrate and phosphate are the most commonly limiting macronutrients in oceanic systems. macroorganisms macroorganismos General term for large organisms, typically visible to the naked eye, as contrasted with microorganisms (qv). macrophyte macrófita A large macroscopic plant or alga, used especially in reference to aquatic forms, especially algae, such as kelps.
Plankton (qv) with maximum dimension on the order of 2 - 20 cm. macroscale feature macroescala Periodic variation in order of years to millennia and/or many hundreds to thousands of kilometers (cf mesoscale feature). macrosmatic Pertaining to an organism possessing a highly developed sense of smell. macrozooplankton macrozooplancton Large zooplankton (qv), 2 to 20 cm in maximum dimension. malacology malacología Study of the biology of mollusks, most commonly used in reference to studies of bivalves and gastropods.
A graphic representation of part or all of the earth's surface including depiction of features of interest to the cartographer and the intended audience.
Study of the biology of marine organisms (ie physiology, biochemistry, etc) apart from their roles in marine ecosystems as contrasted with biological oceanography (qv). marine ecology ecología marina Ecology (qv) of marine organisms. marine mammal mamífero marino A mammal that carries out all or virtually all life history functions in the marine environment. All except cetaceans and sirenians come ashore for courtship, breeding, birthing and early care of the young. Includes mammals in the orders Cetacea, Sirenia, Pinnipedia, and Carnivora (Enhydra, and, considered by some, Ursus maritimus). marine snow nieve marina Organic aggregates formed by micro-organisms in association with detritus. maximum sustained yield cosecha máxima sostenible The maximum yield or crop which may be harvested year after year without damage to the system; applied to agriculture, husbandry, and exploitation of natural populations by humans; commonly employed abbreviation: MSY. megaplankton megaplacton Plankton (qv) with maximum dimension on the order of 20 - 200 cm. meiobenthos meiobentos Benthic organisms such as foraminifera, small nematodes and juvenile macroinvertebrates, 100 - 1000 mm in maximum dimension.
Term used to describe objects or events mainly in a latitudinal (north-south) direction, eg the meridional flow of eastern and western boundary currents (cf zonal). meristic character caracter merístico A character that can be counted, such as number of vertebrae, number of fin rays, number of setae, etc.
Pertaining to a permanently stratified lake, usually resulting from a significant temperature or salinity difference (and hence density difference) between the epilimnion (qv) and hypolimnion (qv).
Aquatic organisms that are only temporary members of the pelagic (qv) community (cf holopelagic).
Invertebrate larvae inhabiting the plankton (qv) only prior to metamorphosis, adults being benthic; also termed hemiplanktonic (cf holoplankton).
See xeric. mesopelagic mesopelágico (1) The stratum between 200 and about 1000 m. (2) Corresponds to the disphotic (qv) zone where light cues result in diel behavioral responses such as diel vertical migration but in which light is insufficient to support net positive productivity. mesophenic See monomorphic. mesoplankton mesoplancton Plankton (qv) with maximum dimension on the order of 0.2 - 20.0 mm mesoscale eddy torbellino de mesoescala An eddy (qv) with a diameter on the order of a few tens to a few hundreds of kilometers, eg warm and cold core rings, persisting over a period of weeks to months (sometimes longer). mesoscale feature mesoescala Periodic variation on the order of weeks to months and/or tens to a few hundreds of kilometers (cf macroscale feature). metapopulation metapoblación A set of partially isolated populations belonging to the same species. The populations are able to exchange individuals and recolonize sites where the species has recently been extirpated (qv).
The atmospheric characteristics prevailing within a small space, usually in the layer near the ground, affected by diel surface temperature changes and by vegetation or lack thereof. microevolution microevolución Evolutionary change within species (as opposed to macroevolution, the origin of higher taxa), may involve anagenesis (qv) or cladogenesis (qv).
The topographic analogue of microclimate (qv) - a spatially definable subunit of a much larger habitat presenting organisms with a particular subset of resource and physiological opportunities and limitations. micronekton micronecton Animals at the interface between plankton and nekton, able to sustain considerable mobility but incapable of maintaining horizontal position against continuous advection. Includes most mesopelagic migratory and nonmigratory fishes, eg Myctophidae, as well as such large zooplankton as euphausiid and sergestid crustaceans. micronutrient micronutriente Organic or inorganic element or compound needed only in relatively small amounts by living organisms for autotrophy (cf macronutrient).
An organism of microscopic or submicroscopic size, especially a bacterium or protozoan (cf macroorganism). microplankton microplancton Plankton (qv) with maximum dimensions on the order of 20 - 200 microns. mictic míctico Pertaining to the pattern of water circulation in a lake, eg holomictic (qv), meromictic (qv), etc. mid-depth species especie de profundidades medias See midwater species. mid-ocean ridge cresta centro-oceánica A topographical feature of the deep ocean floor comprising mountain ridges, rift valleys, and so forth, presumed to be sites of formation and spreading of new ocean floor, eg the Mid-Atlantic Ridge, Carlsberg Ridge, East Pacific Rise, etc. midwater species especie de profundidades medias For oceanic species, a catchall term applied to meso- and bathypelagic species. migration migración (1) Nonrecurrent directional movement or recurrent seasonal movement (as by tuna). (2) Recurrent daily movement for feeding and for shelter-seeking or other purposes, eg diel vertical migration or (coastal) daily on/off reef migration by fishes such as squirrelfishes, grunts and some snappers. milky seas mar lechoso Seas in which surface waters are brilliantly lit (visible at night) by bioluminescent organisms (presumably bacteria or protists). Milky seas may extend (in shipboard perspective) from horizon to horizon. They have been most commonly reported in the equatorial and north Indian Ocean. mixed layer capa de mezcla Surface layer of the sea in which essentially isothermal conditions (above the main or seasonal thermocline) result in virtually isopycnal (qv) conditions throughout the layer, allowing complete mixing and overturn within the layer by the wind. molecular clock reloj molecular The hypothesis that point mutations occur at a sufficiently regular interval to permit the dating of phylogenetic dichotomies (cladogenesis, qv). It assumes a direct relationship between the extent of molecular divergence and the time of ancestral separation of the two branches. monomictic monomíctico Applied to lakes in which only one seasonal period of free circulation (turnover) occurs each year. Typical of high latitude lakes.
Pertaining to a population or taxon showing no genetically fixed discontinuous variation, therefore comprising a single discrete morph. Continuous (unimodal) variation may occur within the population with an extremely broad (latiphenic), moderately broad (mesophenic), or narrow (leptophenic) range of expressed variation.
Phylogeny: A group based on propinquity of descent, includes only branches meeting the cladistic definition of relationship (qv) and includes all such branches for the level of the cladogram in reference (holophyletic). monothetic monotético Applied to a taxon defined uniquely by autapomorphy, ie by one or more uniquely diagnostic derived feature(s) shared by all members of that taxon but not with members of any other taxon (except via homoplasy (qv)). monotopic monotópico Occurring in a single locality or geographic area (cf polytopic). monotypic monotípico A taxon containing only one immediately subordinate taxon, as a genus containing only one species.
A species not divided into recognizably different subspecies or genetically different populations (cf polytypic species).
A seasonal change of wind field direction and associated climatic properties (especially rainfall) resulting from widespread temperature changes over land and water in the subtropics.
Refers to complete reversals of current flow in the equatorial Indian Ocean associated with the alternation of the Southwest and Northeast Monsoons.
Morphological transformation series - a graded series of character states of a homologous character.
(1) Taxonomy - A specimen selected to represent a given intrapopulation variant (morph); has no official ICZN status. (2) Evolution - A list of the morphological character states presumed present in an ancestral species. mosaic evolution evolución en mosaico Differential rates of evolution of various adaptive attributes within the same evolutionary lineage. motile móvil Moving or having the power to move spontaneously. MSY See maximum sustained yield . multivariate miltivariado Statistical techniques or approaches using more than one variable simultaneously to describe similarities and differences between the groups or factors of reference.
Genetics: Process by which a gene or chromosome undergoes structural change. mutualism mutualismo A form of symbiosis (qv) in which both parties (species, individuals) benefit from the association. Facultative mutualism is sometimes considered a coordinate alternative category: protocooperation (qv) (cf amensalism, commensalism). N n. sp. Abbreviation of the Latin species nova, new species. nanoplankton nanoplancton Plankton (qv) with maximum dimension on the order of 2.0 - 20.0 microns nascence The origin or commencement of a community in a previously barren area. natatorial natatorio Adapted for swimming. native species especie nativa A species considered to occur naturally in a given geographic area, as contrasted with an introduced (qv) species. natural classification clasificación natural A hierarchical classification based on hypothetical phylogenetic relationships such that the members of each category in the classification share a single common ancestor (cf artificial classification). natural selection selección natural Differential survival and reproduction in which the total environment determines which individuals (on average) survive to reproduce and pass their genes to the next generation. nautical mile milla náutica (1) International: a secondary SI unit equal to 1,852 m, the average distance on Earth's surface subtended by one minute of latitude. (2). A secondary fps unit, 6080 feet (UK) or 6080.27 feet (U. S.), the average distance (approx.) on Earth's surface subtended by one minute of latitude. NE monsoon monsón NE A seasonal wind field associated with cold temperatures and high pressure over the Asiatic mainland, in the northwestern Indian Ocean; the Northeast Monsoon blows from northeast to southwest during the period November to March. neap tides mareas de cuandratura Lower than average tides (qv) associated with quadrature (qv) of sun and moon. nearshore costero, nerítico Areas of inner neritic (qv) zone. negative binomial distribution distribución binomial negativa A mathematical distribution used to model aggregated or contagiously dispersed populations (qv).
An estuary whose waters have salinities greater than the adjacent sea, as contrasted with a normal estuary of lower salinity (cf estuary, neutral estuary). nekton necton Animals capable of maintaining position and even moving against local water currents, eg migratory fishes such as tunas. neontology neontología Science dealing with the life of Recent organisms (cf paleontology). neoteny neotenia Attainment of sexual maturity in an immature or larval stage. neotype neotipo Taxonomy: A specimen selected as type subsequent to the original description in cases where the original type(s) (holotype, syntype(s)) are known to have been destroyed. nepheloid layer capa nefeloide A turbid layer of ocean water, usually at or near the bottom of the deep ocean, carrying very fine suspended particulate matter. neritic nerítico The coastal zone of the ocean, extending from the shoreline, over the continental shelf, to the shelf break (covers 8% of the total ocean floor). Both benthic and pelagic organisms compromise the neritic flora and fauna. neritopelagic nerítico-pelágico Inhabiting the shallow coastal water column over the continental shelf. net plankton plancton de red General term for planktonic organisms large enough and strong enough to be retained by a net of given mesh size. net primary production producción primaria neta See primary productivity. neuston Pelagic organisms in the uppermost surface or near-surface layer of the sea; "euneuston" - organisms with maximum abundance at the surface day and night; "facultative neuston" - concentrate at the surface only during feeding; "pseudoneuston" - reach the surface layers at least during certain hours, but do not exhibit maximum abundance at the surface. neutral estuary estuario neutral A semienclosed body of water with salinity neither substantially higher or lower than the adjacent sea, with which it is connected by a restricted opening (cf estuary, negative estuary). neutralism neutralismo Situation in which two species populations coexist with neither population measurably affected by association with the other.
The present barrier to east-west travel/transport/dispersal of tropical and temperate marine organisms imposed by interposition of the North, Central and South American land masses between the Atlantic and Pacific Oceans. niche nicho Ecology: The functional position of an organism in a community including its interaction with all physical, chemical and biological parameters of the environment that impact that position. niche breadth amplitud del nicho Range of resources used by a species in its local situation. niche diversification diversificación del nicho The hypothesis that diversity grows with time in a community as finer and finer division of resources (niches) allows more "packing" of species into a community. Concomitants are increased species richness (qv), increased equitability (qv) (lower dominance), and a closer approach to an "equilibrium" (qv) view of species composition (cf biological accommodation). niche overlap superposición de nichos Joint use of resources or environmental variables by two species - not necessarily related to competition.
Change in resource use patterns by one species when another species (usually a competitor) is added to or removed from a system.
Bioluminescent. nocturnal nocturno Active at night (cf diurnal, crepuscular). node nodo (1) Systematics: A branching point in a dendrogram (qv). (2) Biogeography: In vicariance biogeography, the location where two "tracks" (qv) (which represent the probable paths of ancestral geographic translocation) intersect (cf panbiogeography).
Taxonomy: Name that as originally published fails to meet all of the mandatory requirements of ICZN and is thus lacking status in zoological nomenclature.
Taxonomy: Forgotten name. A name that has not been used in the zoological literature for at least 50 years. Such names, even if available senior synonyms, should not be used without prior ICZN permission.
Taxonomy: The system of scientific names applied to taxa or the process of application of these names.
Taxonomy: A specimen acting as a name-bearer (cf onomatophore). nominate nominado Taxonomy: Used of a subordinate taxon (subspecies or subgenus) containing the type of the higher taxon and bearing the same name.
A graph on which temperature and density contours are plotted against salinity for given field data. Used in the depiction of T-S curves (qv) and T-S envelopes (qv), and for water mass identification and description.
Properties of sea water changed in situ, not just at major hydrosphere interfaces, by some nearshore and sedimentary processes but mainly by the activities of living organisms. Such properties include alkalinity, nutrient content, organic content, dissolved oxygen content, pH, and the extinction coefficient, among others (cf conservative property). nonparametric statistic estadística no paramétrica A so-called "distribution-free" statistic (qv), one that does not involve assumptions of an underlying normal distribution, homoscedascity (qv) of variances among groups, etc., that are prerequisite to use of parametric statistics such as Analysis of Variance (ANOVA). normalizing selection selección normalizante Stabilizing selection (qv). Northeast Monsoon See NE Monsoon. NTSYS (NTSYS-PC) NTSYS (mainframes), NTSYS-PC (IBM compatible microcomputers). A widely used package of programs for phenetic analyses, developed by J. Rohlf, Exeter Publishing Ltd. null hypothesis hipótesis nula Statistics: The hypothesis that no real difference or association exists between two populations or between observed values and an underlying expected distribution, and that therefore any deviation observed is due to chance alone. Denoted by Ho. numerical response respuesta numérica Ecology: A change in the number of predators in a predator population as a result of a change in prey density (cf functional response).
Phylogeny: Also called phenetics. Grouping is based on relationship defined as unweighted overall similarity. As many characters as practicable are utilized as well as a variety of measures of similarity/distance and grouping algorithms.
Zone of rapid change of nutrient concentration with distance (typically with depth). nutrient nutriente Any chemical compound or element in sufficiently short supply that it limits or potentially limits autotrophic productivity and whose addition to a system (under defined circumstances) will enhance that productivity (cf biogeochemical cycle, micronutrients, macronutrients). nyctipelagic nictipelágico Pertaining to organisms that migrate into surface waters at night. O obex Any barrier separating populations (obices). obligate obligado Essential; necessary; unable to exist in any other state, mode or relationship (cf facultative); eg obligate cleaning symbiont. occidental Western; westerly (cf oriental). ocean color color del océano Division of reflection of visible light from the sea surface into a number of frequency (wave length) bands corresponding to what we perceive as different colors. A number of processes, including biological productivity are closely indexed by color at the sea surface. Detection outside the visible portion of the spectrum, especially in the infrared, may be used in similar fashion. oceanic oceánico The environment of the open sea beyond the neritic zone, ie seaward of the shelf break. Both pelagic and benthic components comprise the oceanic environment, although most commonly used with reference to the pelagic system.
The largest water mass in the world, forming deepwater in the Indian and Pacific Oceans, with mean temperature about 1.5° C and mean salinity about 34.7 ppt.
A volcanic island formed independently of and never connected to any continental land mass.
Pertaining to organisms that migrate only within the marine environment (cf diadromous, potamodromous).
Study of the physics, chemistry, geology and biology of the oceans. œcesis See ecesis. offshore mar adentro General term for ocean regions not in close proximity to land (cf inshore) -oidea Suffix; ending of a name of a superfamily in the zoological literature. -oideae Suffix; ending of a name of a subfamily in the botanical literature. oike Habitat (qv). Old World Land Barrier barrera terrestre del Viejo Mundo The barrier to free interchange of tropical and subtropical marine organisms between the Atlantic and Indian Oceans caused by the interposition of Africa and southwest Asia.
Applied to lakes that are seasonally stable, only rarely (if at all) exhibiting overturn. True of most tropical lakes with very warm surface waters.
Poor in inorganic nutrients, primary production will be nutrient limited even where other conditions for sustained high levels of productivity are favorable. Often applied to the so-called "blue-water areas" of exceedingly low productivity most strongly characterized by the central portions of the subtropical anticyclones. Also applied to poorly productive lakes which are often (in various combinations) temperate, alpine, cold, deep (cf eutrophic, dystrophic).
Heterotrophic consumption of live plant and animal material (cf carnivorous, herbivore, detritovore). onomatophore onomatóforo, portador de nombre Taxonomy: A nomenclatural type (holotype, syntype, lectotype, neotype, qv); a specimen acting as the name bearer (cf nomenifer), ontogeny ontogenia The developmental history of an individual organism from egg (zygote, spore, etc.) to adult.
Fine-grained deepsea sediments (siliceous or calcareous) of biological origin (containing greater than 30% of the naming constituent; cf diatom ooze, foraminiferan ooze, Globigerina ooze, pteropod ooze, radiolarian ooze). open net haul lance con red sin apertura-cierre A net fished open (lacking or not employing discrete depth sampling capabilities) typically from depth to surface (cf discrete depth sampling).
Fugitive species (qv). -opsida Suffix. The ending of the name of a class in the botanical literature. optimal óptimo Most favorable; pertaining to the levels of environmental factors best suited for growth and reproduction (cf pessimal, optimal foraging, optimal yield, etc).
Idea that selection favors prey utilization that maximizes net energy gain per unit of predator feeding time and/or effort.
Fisheries: The MSY (cf maximum sustained yield) under a given set of environmental conditions. ordination ordenamiento Numerical methods for arranging individuals or attributes along one or more lines. Commonly used in ecology to represent distance in multidimensional space in coordinates of 2 or 3 dimensions (2-space or 3-space). oriental Eastern, easterly (cf occidental). orogeny orogenia The process of mountain formation. orthogenesis ortogénesis (1) Evolution of phyletic lines following a predetermined rectilinear pathway, the direction not being determined by natural selection (cf directional selection, anagenesis). (2) The result of directional selection or "orthoselection" where directionality of selective forces is maintained over evolutionary time. osmoregulation osmoregulación Physiologically, the process whereby marine or freshwater organisms maintain their osmotic balance at an osmotic pressure different than that of the ambient waters (cf hyperosmotic, hypoosmotic, isosmotic). OTU Operational taxonomic unit. Jargon first put forward by the pheneticists in their search for objectivity, but now used almost universally. Each of the taxa of whatever rank (typically species or genera) that form the elements of an attempt at classification. N. B. it takes at least three OTU's to meaningfully discuss taxonomic relationship, however one chooses to define and estimate relationship. outgroup Phylogeny: The taxon (taxa) selected for comparison with the study taxon (ingroup) for purposes of developing transformation series hypotheses (basically primitive ===> derived). Use is expressed by the so-called Outgroup Rule: Given two characters (states) that are homologous and found within a single phylogenetic group, the character (state) that is also found in the sister-group (outgroup) is the plesiomorphic state.
Enrichment of coastal waters by flushing of nutrient materials from coastal estuaries and embayments (cf upwelling).
A situation where individuals in a population do not occur randomly with respect to one another but exhibit clumping, such that the presence of one is associated with enhanced probability of another nearby (cf even, random). In overdispersion samples tend to have either a large number of individuals per sample or none at all (cf. Aggregated, dispersion). overturn mezcla Thorough (vertical as well as horizontal) water circulation in the sea or in fresh water, often occurring seasonally, and often caused by density differentials induced by seasonally changing temperatures. oxygen debt deficiencia de oxígeno Physiologically, the result of oxygen being utilized more rapidly (usually through extensive or rapid muscular exertion) than can be replaced by the normal oxygen delivery system. Organisms typically employ various anoxic metabolic mechanisms until the oxygen debt can be repaid. oxygen deficit layer See oxygen minimum layer. oxygen isotope ratio relación entre los isótopos del oxígeno The ratio of 18O2 to 16O2, used to estimate temperatures that existed at particular periods in earth history, eg from the ratio of these isotopes in fossil marine shells (from the oxygen in the CaCO3). Enhancement of 18O2 indicates warmer temperatures. oxygen-minimum layer capa de mínimo oxígeno A markedly hypoxic, in some areas thick (hundreds of meters vertically), layer of oxygen poor water, typically between 100 and 1000 m below the surface. Oxygen minimum layers are especially pronounced in the eastern tropical Pacific, the northern Indian Ocean, and the eastern tropical Atlantic. P, Q
Production / biomass ratio. In mass terms the ratio between net primary production and standing stock (living and dead) of autotroph biomass. Typically P/B values are very high for oceanic communities and very low for terrestrial communities such as forests. Pacific Ocean Océano Pacifico Largest of the world's oceans (179.7 X 106 km2). It is also (on average) the coldest (3.36° C), deepest (4,028 m) and least saline (34.62 ppt).
Heterochrony (qv) that results in reproduction by forms that have larval or other immature characteristics. paedomorphosis paidomorfosis Evolutionary change that results in retention of juvenile characters in adults. paleocirculation paleocirculación Pre-existent patterns of oceanic circulation detected by sedimentary, isotopic and fossil analyses, amongst other clues.
Science dealing with the life of past geological periods, in time preceding Recent (cf neontology). palingenetic palingenético Ancestral; of remote or ancient origin. paludal palustre Pertaining to marshes (cf helic, palustrine). palustrine palustre Pertaining to wet or marshy habitats. Lentic habitats substantially filled with aquatic vegetation.
Term coined by L. Croizat to describe a new synthesis of plant and animal biogeography. Central features include the recognition of "tracks" ( = generalized tracks (qv)) and "nodes" (where different tracks intersect). These and other of Croizat's ideas formed the basis for vicariance biogeography (qv). panchestron An explanation of such ambiguity that it can be taken to explain almost anything. pandemic pandémico Very widely distributed; ubiquitous; cosmopolitan. Pangea A single supercontinent which came into being in late Permian times and persisted about 40 million years, until it began to break up at the end of the Triassic Period. Its division resulted in the northern Laurasia (ultimately much of North America, Europe, and Asia) and the southern Gondwanaland (ultimately South America, Africa, south Asia, Australia and Antarctica). panmixis Random mating of individuals in a population (as opposed to assortative mating where mate preference based on morphological, behavioral or other features is expressed).
The universal ocean surrounding Pangea (qv). pantropical Circumtropical (qv). paradigm paradigma Essentially a large-scale and generalized model providing the current viewpoint from which the real world is perceived and studied. Scientific progress is measured by a succession of reigning paradigms. paradox of the plankton paradoja del plancton Phrase coined by the limnologist G. E. Hutchison: the observation that recognizable niche axes available to planktonic organisms (especially phytoplankton) appear to be too few to account for existing diversity in light of the competitive exclusion (qv) principle. parallelism paralelismo The independent acquisition of similar character states in related evolutionary lines [(cf convergence); parallelism and convergence are continuous on a gradient of degree of "relatedness", a concept almost never rigorously defined] (cf homoplasy). parameter parámetro Statistics: A characteristic of the distribution of a variable or population, such as the mean or variance, usually denoted by Greek letters (cf statistic).
A body of statistical techniques based on similar assumptions about underlying distributions and properties - normality, homoscedasticity (qv) of group variances, etc.
(1) Speciation in which geographical isolation between presumptive daughter species (qv) is incomplete. In the sea viewed as a consequence of very large species-range sizes with differing selective pressures, due to ecological differences, resulting in discontinuous variation and disruptive changes in characters. (2) Speciation that occurs despite minor gene flow between demes (qv). Selective pressures are sufficiently strong to prevent homogenization of the immigrant genes by interbreeding. parapatry parapatria The condition where populations or species in nonoverlapping distributions make contact without interbreeding.
Phylogeny: (1) An artificial grouping based on symplesiomorphy, ie sharing of primitive character states. (2) Pertaining to a taxon including some but not all descendents of the common ancestor.
An organism, usually markedly smaller in size, that gains benefit from another organism, the host, to the detriment of the host. parasitism parasitismo Interaction of species populations where one derives benefits to the detriment (even to the death) of the other. Similar to predation except: (1) it is usually slow (by degree); (2) the species benefiting (the parasite) is often much smaller than the host, living on it or in it; and (3) in many cases the parasite may weaken but not kill the host. paratype paratipo Taxonomy: A specimen or specimens other than the holotype before the author at the time of preparation of the original description of a species and so designated or indicated by the original author. Paratypes have no "name-bearing" status (are not onomatophores (qv)) in the ICZN. parsimony parsimonia The search for the simplest explanation not contradicted by the facts. Parsimony is the holy grail of cladistic methodology, one sometimes feels that cladists think they invented it. Yüklə 0,85 Mb. Dostları ilə paylaş:
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