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Glossary of Terminology: B

The glossary is organized alphabetically by page -- A through Z. Literature sources are listed on the References Page.

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Glossary Pages

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Number of records found : 247

Image of bacteria (bacillus)

Image of rod-shaped bacterium, Bacillus infernus, collected from deep (20-2800 meters) terrestrial subsurface. (Photo: U.S. Dept. of Energy/Subsurface Microbial Culture Collection)

bacillus - a bacterium with a rod-like shape

Image of reef lagoon and back reef zone

Emergent coral heads in a back reef zone. (Photo: Great Barrier Reef Marine Park Authority)

back reef - the shoreward side of a reef, including the area and sediments between the reefcrest/algal ridge and the land. It corresponds to the reef flat and lagoon of a barrier reef and platform margin reef systems

backcross - crossing an organism with one of its parents, or with the genetically equivalent organism. The offspring of such a cross are referred to as the backcross generation or backcross progeny

background level - the concentration or level of a substance or other factor in an environment that is not the result of human activities, e.g., background levels of chemicals, light, sound, etc

background noise - noise coming from sources other than the noise source being monitored

backscatter - the deflection of acoustic radiation in a scattering process through an angle greater than 90 degrees. Backscatter is the term commonly used to describe the return of energy from the seabed to the receiver in an active sonar

bacterial bleaching - loss of zooxanthellae with resultant bleaching caused by a specific bacterial infection, as opposed to environmental stress. The bacteria (Vibrio sp.) produce a toxin which cause lysis of the zooxanthellae. For additional information and illustrations, see:

bacterial bleaching hypothesis (BB) - an alternative hypothesis that mass coral bleaching is triggered by the presence of bacteria in the genus Vibrio, rather than from thermal stress

bacterial chlorophyll - chlorophylls (bacteriochlorophylls a, b, c, d, e, and g) found in photosynthetic bacteria. They differ from plant chlorophyll in chemical construction and absorption spectra characteristics

bacterial generation time - the time interval required for a bacterial cell to divide, or for a population of bacterial cells to double. Generation times for bacterial species growing in nature may be as short as 15 minutes or as long as several days

bactericide (bacteriocide) - a substance that kills bacteria

bacteriophage (phage) - a virus that attacks and infects bacterial cells. Phages consist of a protein coat enclosing the genetic material, DNA or RNA, that is injected into the bacterium. Upon infection, synthesis of host DNA, RNA and proteins ceases and the phage genome is used to direct the synthesis of phage nucleic acids and proteins using the host's transcriptional and translational apparatus

balanced polymorphism - a type of polymorphism in which the frequencies of the coexisting forms do not change noticeably over many generations

ballast - a weight at the bottom of the boat to help keep it stable. Ballast can be placed inside the hull of the boat or externally in a keel. Water picked up as ballast in one location may be released in another, and in doing so, may introduce non-native species

Image of butterflyfish

Chaetodon striatus, the banded butterfly fish, has two black bands of pigment encircling its body. (Image: NOAA)

band - a thick, pigmented vertical marking that encircles the circumference of an organism's body

bank - a broad elevation of the sea floor around which the water is relatively shallow but not a hazard to surface navigation

bank reef - large reef growths, generally having irregular shape, which develop over submerged highs of tectonic or other origin and are surrounded by deeper waters

bank/shelf - deepwater area extending offshore from the seaward edge of the fore reef to the beginning of the escarpment where the insular shelf drops off to the deep, oceanic water. If no reef crest is present, it is the flattened platform between the fore reef and the deep ocean waters or between the intertidal zone and open ocean

Image of gramma (fish)

The royal gramma, Gramma loreto, has a darkly pigmented bar across its eye.

bar - a thick, pigmented vertical marking that does not encircle the body of an organism; an elongate submarine shoal

bar - unit of pressure of one million dynes per square centimeter

barb - a type of spine armed with teeth pointing backwards

Image of yellow goatfish

A yellow goatfish with two prominent barbels protruding from its chin. (Photo: NOAA)

barbel - a slender elongate sensory structure protruding from the lips or jaws of certain fishes, such as catfishes, goatfishes, drums, cods, and many deep-sea fishes. Barbels may appear singly or in groups. They are primarily tactile in function but may also bear tastebuds, allowing the fish to taste its environment

barcode - short nucleotide sequences from a standard genetic locus for use in species identification

Barcode of Life - a project to create a public collection of reference sequences from vouchered specimens of all species of life. A Barcode sequence is a short nucleotide sequence from a standard genetic locus for use in species identification. For animals, this standard genetic locus is a 650 base pair region on the 5' end of the mitochondrial cytochrome oxidase subunit I (COI) gene.

barometer - an instrument for measuring air pressure

barophile - a microorganism which grows best (or can only grow) in high-pressure environments, such as deep-sea environments

barotrauma - an injury that results from rapid or extreme changes in pressure. Scuba divers may experience ear barotrauma, a condition of discomfort in the ear caused by pressure differences between the inside and the outside of the eardrum

barrel - a unit of volume equal to 42 U.S. gallons or 159 liters at 60 o F, often used to measure volume in oil production, transportation, and trade

barren zone - the region of a coral reef seaward of the lower palmata zone and just landward of the buttress or mixed zone

barrier - in biogeography, an environment that prevents or impedes the dispersal of a species from one location to another

Image of barrier island

Cape Lookout National Seashore currently consists of 4 barrier islands. (Photo: U.S. National Park Service)

barrier island - a long, usually narrow accumulation of sand, that is separated from the mainland by open water (lagoons, bays, and estuaries) or by salt marshes

Image of a healthy barrier reef (Australia)

Healthy Acropora coral in Australia's Great Barrier Reef. (Photo: Ray Berkelmans/Great Barrier Reef Marine Park Authority)

barrier reef - a long, narrow coral reef, roughly parallel to the shore and separated from it by a lagoon of considerable depth and width. It may lie a great distance from a continental coast. It is often interrupted by passes or channels

basal - of, at or forming a base

basal plate - lower part of the coral cup, separating the polyp from the substratum. A synonym of pedal disc

basalt - a dark, fine-grained igneous rock composed of minerals rich in ferromagnesian silicates

base - a substance that reduces the hydrogen ion concentration in a solution

base - in genomics, a key component of DNA and RNA molecules. Four different bases are found in DNA: adenine (A), cytosine (C), guanine (G) and thymine (T). In RNA, uracil (U) substitutes for thymine; also known as nitrogenous bases; a base, a phosphate molecule and a sugar joined together constitute a nucleotide

Diagram of base pairs in DNA

Diagram of a DNA molecule. (Diagram: U.S. NIH/Human Genome Project)

base pair - two nitrogenous bases which form a "rung of the DNA ladder." A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a base molecule. The bases are the "letters" that spell out the genetic code. In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine. In RNA, thymine is replaced by uracil

base pairs (bp) - pairs of nucleotide bases in DNA

base sequence - the order of nucleotide bases in a DNA molecule

baseline data - a quantitative level or value from which other data and observations of a comparable nature are referenced

basic research - research conducted with the sole goal of obtaining knowledge; in contrast with applied research

basicaudal - on the base of the caudal fin of fishes

basicaudal spot - a spot on the base of the caudal fin, common in many unrelated fish species

basilar - forming a foundation

basipinacocyte - a pinacocyte that adheres a sponge to a substrate by the external secretion of a collagenous matrix

basket star - a basket star is a specialized type of brittle star (Echinodermata). It has a series of complexly branched arms which are used to capture plankton

basophylic - having an affinity for basic dyes

Batesian mimicry - a type of mimicry in which a harmless species resembles a different species that is unpalatable, poisonous, or otherwise noxious or harmful to a predator

bathymetric map - a map which delineates the form of the bottom of a body of water by the use of depth contours (isobaths)

bathymetry - the science of measuring ocean depths to determine the topography of the sea floor

baud - unit of data transmission speed of one bit per second

beach - an aggregation of unconsolidated sediment, usually sand, that covers the shore

beak - in cephalopods, one of two chitinous mandibles (jaws) used primarily to cut prey tissues during feeding

beam - the widest part of a vessel

Image of "beche-de-mer", an edible sea cucumber

Image of the commercially harvested -beche de mer+.

beche-de-Mer - commercially harvested sea cucumbers (Class Holothuroidea). In Asia, it is considered to be a delicacy

bedrock - the solid rock of the earth's crust that lies under the soil and other unconsolidated earth materials

behavioral isolating mechanism - a difference in behavior (usually reproductive behavior) that prevents genetic exchange between members of different populations or species

bel - unit of noise intensity equal to ten decibels

belt transect - a linear or circular transect with the observation area being a specified distance on either side of the transect line

benchmark - a measurement or standard that serves as a point of reference by which process performance is measured

benign introduction - the purposeful introduction of members of a species into an appropriate habitat, foreign to the "home" habitat or area, for the purposes of conservation of that species

benthic - bottom dwelling; living on or under the sediments or other substrate

benthic organism (benthos) - an organism whose habitat is on or near the bottom of a stream, lake, or ocean

Image of benthic crab

A benthic crab (phylum Arthropoda).

benthic region - the bottom layer of a body of water

beta animal - in animal behavior, the subordinate or second animal in a social group

beta particle - a high-speed particle, identical to an electron, emitted from an atomic nucleus

beta taxonomy - in taxonomy, the process of arranging taxa into higher categories which reflect the evolutionary history of a group of organisms.

BibTex - a reference management software for formatting lists of references. BibTeX makes it easy to cite sources in a consistent manner, by separating bibliographic information from the presentation of this information

bicentric distribution - the presence of a species (or other taxonomic unit) in two widely separated geographic areas

bicuspid - having two cusps or points

bifacial - describes plates which have corallites on both sides

bifid - divided or cleft into two parts or lobes

bifurcate - a coral branch that divides into two equal branches

Big Old Fat Fecund Female (BOFFF) hypothesis - in all species of fishes, the older larger females produce more eggs than the younger smaller ones. In some species, the larger older females can produce exponentially greater quantities of eggs. The BOFFF hypothesis refers to this phenomenon

bigeye - any species of bony fishes in the family Priacanthidae. Bigeyes ( also called "catalufas") are most typically colored bright red, but other coloration patterns exist. The common name of "bigeye" refers to their unusually large eyes which are adapted their predatory and nocturnal behavior. Most species reach lengths of 12-20 inches. Bigeyes are generally associated with rock formations or coral reefs

bigeye - any species of bony fishes in the family Priacanthidae. Bigeyes ( also called "catalufas") are most typically colored bright red, but other coloration patterns exist. The common name of "bigeye" refers to their unusually large eyes which are adapted their

bight - an indentation of the coast forming a large open bay

bilateral symmetry - a bilaterally symmetric organism is one that is symmetric about a plane running from its frontal end to its caudal end (head to tail), and has nearly identical right and left halves. Most animals are bilaterally symmetrical. The exceptions are sponges (no symmetry), cnidarian polyps and medusae, and ctenophores (radial symmetry), and echinoderms (partial radial symmetry).

Bilateria - group containing all multicellular animals with bilateral symmetry; the name has no taxonomic status

Diagram of bimodal distribution chart

Chart showing a population of data having a bimodal distribution.

bimodal - a distribution in which the frequency curve has two peaks. A single peak is called a mode

bimodal curve - a frequency curve characterized by two peaks

Photo of dividing bacteria

A bacterial cell reproducing by binary fission. The two resultant daughter cells are genetically identical. (Photo: Dr. Vincent A. Fischetti, Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller University)

binary fission - type of cell division found in prokaryotic cells, in which dividing daughter cells each receive a copy of the parental chromosome

binding - the ability of molecules to stick to each other because of the exact shape and chemical nature of parts of their surfaces

binding site - the reactive part of a macromolecule that directly participates in its specific combination with another molecule

binomen - a two-part name given to a species in which the first part is the name of the genus and the second is the specific name

binomial nomenclature - a system of nomenclature where each animal has a dual name consisting of genus and species, e.g., the boulder coral, Montastrea annularis

bioaccumulation - the buildup of chemical substances in the cells or tissues of an organism

bioacoustics - a discipline of zoology that is concerned with sounds of biological origin: their mechanisms of production, physical properties, receptors and reception physiology, and the role of the sounds in behavior

bioassay - an assay for the activity or potency of a substance that involves testing its activity on living materials

bioaugmentation - the addition of microorganisms to the existing native oil-degrading population

biochemical cycle - the flow of an element through the living tissue and physical environment of an ecosystem, e.g., the carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus cycles

biochemical genetics - the study of the relationships between genes and enzymes, specifically the role of genes in controlling the steps in biochemical pathways

biochemical oxygen demand (BOD) - the amount of oxygen taken up by microorganisms that decompose organic waste matter in water. It is therefore used as a measure of the amount of certain types of organic pollutant in water. A high BOD indicates the presence of a large number of microorganisms, which suggests a high level of pollution

biochip - an electronic device that uses organic molecules to form a semiconductor; a microchip that uses tiny strands of DNA to latch onto and quickly recognize thousands of genes at a time; collection of miniaturized test sites (microarrays) arranged on a solid substrate that permits many tests to be performed at the same time in order to achieve higher throughput and speed. A biochip can perform thousands of biological reactions, such as decoding genes, in a few seconds. Biochips can also be used to rapidly detect chemical agents used in biological warfare so that defensive measures can be taken

biochore - a group of similar biotopes

bioclastic sediment - a sediment type composed of fragments of organic skeletal materials

biocoenose - an assemblage of diverse organisms inhabiting a common biotope

biocoenosis - a community or natural assemblage of organisms. The term often is used as an alternative to ecosystem, but strictly it is the fauna/flora association excluding physical aspects of the environment

biocycle - a subdivision of the biosphere, e.g., a biochore

biodegradable - capable of undergoing rapid decomposition by microorganisms under aerobic and/or anaerobic conditions. Most organic materials are biodegradable

An image of a biologically diverse coral reef

A coral reef contains a great variety of species of all major kingdoms of living forms. (Photo: Dr. Anthony Picciolo)

biodiversity - the total diversity and variability of living things and of the systems of which they are a part. This includes the total range of variation in and variability among systems and organisms at the bioregional, ecosystem and habitat levels, at the various organismal levels down to species, populations and individuals and at the level of the population and genes

biodiversity hot spot - an area that features exceptional concentrations of species, including many endemics. Many such hot spots also experience large habitat losses, putting these ecosystems at risk

biodiversity indicators - in conservation biology, sets of species or taxa whose presence may indicate areas of high species richness

bioerosion - erosion of the physical/geological environment by organism activities such as boring, scraping, etching, etc.

biofuel - any liquid, gaseous, or solid fuel produced from plant or animal organic matter

biogenesis - a central concept of biology that all living organisms are descended from predecessor living organisms

biogenic - refers to things which came about as a result of the activities of living organisms

biogenic reef - a mound-like layered structure built by and predominantly composed of organic remains such as shells and skeletons of sedentary organisms

biogenic rock - an organic rock produced by the physiological activities of plants or animals

biogenous - produced by living organisms

biogenous sediment - sediment that is composed of the skeletons and shells of marine organisms, primarily plankton

biogeochemical cycle - the chemical interactions among the atmosphere, biosphere, hydrosphere, and lithosphere

biogeography - a branch of biology that deals with the geographical distribution of organisms

bioherm - a body of rock built up by or composed mainly of sedentary organisms, e.g., hard corals, calcareous algae or mollusks, and enclosed or surrounded by rock of different origin

bioinformatics - the analysis of biological information using computers and statistical techniques; the science of developing and utilizing computer databases and algorithms to accelerate and enhance biological research. Bioinformatics is particularly important as an adjunct to genomics research, because of the large volume of complex data generated

biolimiting - relating to the environmental factors determining or restricting the growth of a particular life form

biolistics - a technique to insert DNA into cells. The DNA is mixed with small metal particles, usually tungsten or gold, a fraction of a micrometer across. These are then fired into a cell at very high speed.

biological clock - an internal biological mechanism which controls certain biological rhythms and biocycles, such as metabolism, sleep cycles, and photosynthesis

biological control - the use of living organisms, such as parasites, disease agents, and predators, to control or eliminate other unwanted living organisms, rather than by using toxic chemicals or other means of elimination

Biological Data Profile of the Content Standard for Digital Geospatial Metadata - provides a common set of terminology and definitions for the documentation of biological data through the creation of extended elements and a profile of the FGDC Content Standard for Digital Geospatial Metadata. Its purpose is to provide a user-defined or theme-specific profile of the FGDC Content Standard for Digital Geospatial Metadata to increase its utility for documenting biological resources data and information. This standard can be used to specify metadata content for the full range of biological resources data and information. It also serves as the metadata content standard for the National Biological Information Infrastructure (NBII)

biological half-life - the time required for one-half of the total amount of a particular substance in a biological system to be consumed or broken down by biological processes when the rate of removal is approximately exponential. Toxic chemicals with a long biological half-life will tend to accumulate in the body and are more likely to be harmful. A substance with a short biological half-life may still accumulate if a portion of it it becomes tightly bound to bone or other tissues, even if most of it is quickly eliminated from the body

biological indicator - an organism, species or community whose characteristics show the presence of specific environmental conditions. Other terms used are indicator organism, indicator plant and indicator species

biological navigation - the ability of certain animals to navigate by instinct to specific sites. Depending upon the species, the cues involved may be related to star patterns, sun angle, polarized light, chemical scents or tastes, or the Earth's magnetic field

biological productivity - the amount of organic matter, carbon, or energy content that is accumulated during a given time period

biological rank - in animal behavior, when a hierarchy of dominance exists between different species which compete for food, water or space

biological rhythm - an overt, measurable activity generated by some internal oscillator (or ‘clock’)

biological survey - collecting, processing, and analyzing a representative portion of the resident aquatic community to determine its structural and/or functional characteristics

Image of a comb jelly displaying bioluminescence

A bioluminescent comb jelly of the phylum Ctenophora.

bioluminescence - light produced by organisms as a result of conversion of chemical energy to light energy

biomagnification - the accumulation and amplification of chemical substances at each succeeding trophic level

biomarker - a characteristic that is objectively measured (at the visual or molecular level) and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacological responses to a therapeutic intervention

biomass - an estimate of the amount of living matter per some unit volume or area

biome - a community of animals and plants occupying a climatically uniform area on a continental scale

biometrics - the use of statistics for the study of biological events

biomineralization - the taxonomically widespread process by which living organisms produce minerals for, inter alia, support, defence, and feeding. These minerals often form structural features such as shells of mollusks, skeletons of corals, tests of echinoderms, and bones of vertebrates

biopharming - to genetically engineer an organism to produce a pharmaceutical drug, vaccine or industrial substance

biophysics - the scientific study of the physics of organisms, their biological structure and processes

bioregion - any geographical region characterized by a distinctive biota

bioremediation - the use of organisms such as plants or microorganisms to aid in removing hazardous substances from an area

biosphere - the thin region surrounding the Earth that is capable of supporting life

biostimulation - with reference to an oil spill, the method of adding nutrients such as phosphorus and nitrogen to a contaminated environment in order to stimulate the growth of the microorganisms capable of biodegradation; also known as nutrient enrichment

biota - all life forms of a given area

biotechnology - biological techniques used in applied research research and product development. In particular, the use by industry of recombinant DNA, cell fusion, and new bioprocessing techniques; any technology that is applied to living organisms to make them more valuable to humans

biotope - an area of relatively uniform environmental conditions, occupied by a given plant community and its associated animal community

biotoxin - any poisonous or venemous substance produced by any living organism

bioturbation - the rearrangement of sediments by organisms that burrow through them and ingest them

biotype - a physiological variety or a group of individuals having distinctive genetic characters in common

biparental - the situation where the young are raised by both parents

bipectinate - having two margins which are toothed, like a comb; descriptive of the gills (ctenidia) of aquatic mollusks

bipectinate gill (ctenidium) - in mollusks, refers to having gill lamellae on both sides of the ctenidial axis

Image of bipinnaria larva

Mature bipinnaria of Pisaster ochraceus, ca 24 days old, raised in culture by T.H.J. Gilmour. (Photo: University of Saskatchewan Archives)

bipinnaria larva - an early starfish larva with ciliated bands running about the periphery

biradial symmetry - a body plan in some cnidarians that has two planes of symmetry rather than the several planes of a radially symmetrical animal, or the single plane of a bilaterally symmetrical one.  Both planes of symmetry are longitudinal and are at right angles to each other.  Both include the aboral-oral axis, which is the axis of symmetry

Image of a spiny lobster

Note the biramous antennules of the spiny lobster.

biramous appendage - a type of appendage that is characteristic of crustaceans. It forks from the basal protopodite to form two branches, the inner endopodite and the outer exopodite. Each of these branches can be composed of either one or more segments. There are many variations on this generalized structure; the branches often possess highly specialized extensions

bit - the smallest unit of information that a computer can store and process. A bit has two possible values, 0 or 1, which can be interpreted as yes/no, true/false, or on/off

bitmap - a format for storing graphics in an uncompressed manner

bitmap image - also called raster or paint images. They are made of individual dots called pixels (picture elements) that are arranged and colored differently to form a pattern. Compared to a vector image, bitmap images are great for photographs because they tend to offer greater subtleties for shading and texture but require more memory and take longer to print. Vector images are best for drawings that need sharper lines, more detail, and easy modification. Vector images require far less printing resources than bitmap images

Image of living scallop

A scallop (class Bivalvia) displays its rows of light-sensitive eyespots.

Bivalvia (Pelecypoda) - a class of Mollusca that includes clams, oysters and mussels. Bivalves are laterally compressed and possess a shell composed of two valves that hinge dorsally and enclose the body. They are common inhabitants of coral reefs

Image of living black coral

Black coral isn't really black. The name refers to the black color of their proteinaceous skeletons. The living colonies are made up of thousands of tiny coral polyps whose colors may be yellow, green or orange. (Photo: Dr. A. Bruckner, NOAA)

black coral - black corals are colonial cnidarians in the Order Antipatharia. They are found throughout the world+s oceans, but are most common in tropical deep water habitats from 30-80 m depth. These species of black coral have rigid, erect skeletons that form branched, bush-like colonies. Black coral is commercially harvested primarily for jewelry, and may be globally threatened in many parts of the world as a result of over-harvesting

Image of black band disease

Black band disease. (Photo: Dr. A. Bruckner, NOAA)

black-band disease - a world-wide disease of corals that is characterized by a dark ring, or band, that separates apparently healthy coral tissue from freshly exposed coral skeleton. It migrates across coral colonies and completely degrades coral tissue. The infecting agent is a synergestic assortment of photosynthetic and non-photosynthetic bacteria. For more details and illustrations, see:

bladder - any sac or cavity used to store liquids or gases

blade - a leaf-like structure

blastocoel - the fluid-filled cavity formed within the mass of cells of the blastula of many animals during the later stages of cleavage

blastocyst - a preimplantation embryo. The blastocyst consists of a sphere made up of an outer layer of cells (trophectoderm), a fluid-filled cavity (blastocoel), and a cluster of cells on the interior (inner cell mass)

blastomere - an undifferentiated cell of a cleaving embryo, and of the morula and blastula stages of embryonic development

blastopore - the opening into the archenteron (primitive gut) of a gastrula. In some animals it develops into the mouth and, in others, into the anus

Image of blastula

A late blastula characterized by a single layer of cells surrounding the central hollow area - the blastocoel (B). The blastomeres at the vegetal pole (VP) are taller than those at the animal pole (AP), making the vegetal pole appear slightly thicker. (Photo: Cell and Developmental Biology Online website (University of Guelph); URL:

blastula - a stage of embryonic development of animals near the end of cleavage (cell division), but before gastrulation. In animals where cleavage involves the whole egg, the blastula usually consists of a hollow ball of cells (blastomeres) surrounding a fluid-filled central cavity, the blastocoel

bleach - to become whitened or colorless by means of stressful agents, such as chemicals, elevated temperatures, exposure to sunlight, etc.

bleaching - the process in which a coral polyp, under environmental stress, expels its symbiotic zooxanthellae from its body. The affected coral colony appears whitened

bleaching index - index based on the strength and duration of local HotSpots to monitor bleaching events

bleaching outbreaks - development of bleaching events

bleaching stressors - environment-induced stress that results in bleaching, e.g., disease, excessive or insufficient light, increased levels of ultraviolet radiation, sedimentation, pollution, salinity changes, and increased temperatures

blenny - the common name of a large group of over 800 species within seven families of bony fishes in the suborder Blennioidei. Blennies are small, usually scaleless fishes with comb-like teeth living in coastal and coral reef areas, including seagrass beds and tidepools. At least one species lives in fresh water. Most are are characterized by possessing blunt foreheads, elongated, tapering bodies, and a continuous long dorsal fin. The pelvic fins are usually anterior to the pelvic fins, and in the jugular in position. Many species are cryptic or inhabit the surge zone. Most are herbivores.

blind test - a method of testing or experimentation, in which an independent observer records the results of any test, drug, placebo, or procedure without knowing the identity of the samples or what result might be expected

blog (weB LOG) - basically a journal that is available on the web. The activity of updating a blog is "blogging" and someone who keeps a blog is a "blogger"

Image of blood cells

Red and white blood cells. The white blood cells are the larger ones with irregular nuclei.The small particles are platelets. (Photo: U.S. National Institutes of Health)

blood - a circulating tissue composed of a fluid portion (plasma) with suspended formed elements (red blood cells, white blood cells, and platelets) that delivers nutrients and hormones to cells and removes wastes; In some invertebrates, the blood is called the haemolymph

bloodworm - a marine polychaete worm used as bait in angling

SeaWiFS image of a coccolithophore bloom, Bering Sea

A SeaWiFS (Sea-viewing Wide Field-of-view Sensor) image of a coccolithophore bloom in the Bering Sea.

bloom - a sudden increase in the biomass of phytoplankton or benthic algae in a given area

Image of moray eel

The blotch-necked moray (Gymnothorax margaritophorus) from American Samoa bears darkly pigmented blotches along its body. (Photo: NPS, Copyright Richard C. Wass)

blotch - a patch or a spot of pigment with irregular edges

blowout - with reference to offshore drilling for oil and gas, a blowout is an uncontrolled flow of reservoir fluids into the wellbore, and sometimes catastrophically to the surface. A blowout may consist of salt water, oil, gas or a mixture of these

blue carbon - carbon stored in the Earth's marine and coastal ecosystems

blue carbon initiative - UNEP in cooperation with the Food and Agriculture Organization (FAO) and the United Nations Education and Science Organization ( UNESCO) have introduced a new concept of Blue Carbon. the Blue Carbon Initiative emphasizes the important role being played by marine and coastal ecosystems in being carbon sinks. The areas where this is possible is with marine vegetation like mangrove forests, sea-grasses, brackish marshes, and salt marshes. This together with terrestrial forests could help to sequester atmospheric carbon in large quantities

Image of blue coral

Blue coral (Heliopora coerulea) from American Samoa. (Photo: NPS, Eva DiDonato)

blue coral - the blue coral, Heliopora coerulea, is an octocoral that has a massive aragonite skeleton and is an important reef builder in some areas

blue revolution - a movement aimed at increasing global human food production using aquacultural techniques, as in fish or shrimp farming

Image of blue-green algae cells

Blue-green algae (Cyanobacteria). (Photo: J. Waterbury, Woods Hole/NASA Astrobiology Institute)

blue-green algae - the former name for the blue-green bacteria, now classified as Cyanobacteria. A group of prokaryotic cells that use chlorophyll on intracytoplasmic membranes for photosynthesis. The blue green color is due to the presence of phycobiliproteins. they occur as single cells, colonies or simple filaments

BOD (Biological (or Biochemical) Oxygen Demand) - the oxygen used in meeting the metabolic needs of aerobic microorganisms in water rich in organic matter (as water polluted by sewage)

body wall - in cnidarians, the wall of a polyp, composed of the outer epidermis, the middle non-cellular mesoglea, and inner gastrodermis which surrounds the gastrovascular cavity

bond - a physicochemical association between atoms

bond energy - the energy required to form a particular chemical bond

boom - a temporary floating barrier used to control the spread of spilled oil to reduce the possibility of polluting shorelines and other resources, as well as to concentrate oil in thicker surface layers, making recovery easier

Image of scuba booties

A pair of booties worn by scuba divers under an open-heeled fin.

booties - short "boots" usually made of neoprene, worn inside open-heeled fins. they protect a scuba diver's feet from rubbing against the fins while swimming, as well as protecting the entire foot while walking to and from a dive site. Booties also provide warmth

boring sponge - a marine sponge that chemically digests the limestone skeletons of corals and other calcareous organisms and structures during its search for food and living space. These "boring" activities can damage a coral reef; also called "excavating sponge"

boss - a columnar, flat-topped coral-algal growth or erosion structure usually found on the upper surfaces of spurs and buttresses

botryoid - shaped like a bunch of grapes

bottlebrush branching - describes a branch with compact radial sub-branches

bottom trawl - a method of fishing in which a large bag-shaped net is dragged along the bottom, behind the vessel. The mouth of the net is kept open by various methods, such as a wooden beam (beam trawl) or large flat boards (otter trawl). Bottom trawling has been very

Image of bottom trawler

Small stern trawler fishing. (Photo: David Comb/New England Biolabs)

bottom trawler - a fishing vessel that uses an open-mouthed fishing net drawn along the sea bottom. This type of fishing is destructive to shallow water and deep sea coral reef communities

bow - the front part of a vessel

Boyle's Law - if the temperature is kept constant, the volume of a given mass of gas is inversely proportional to the absolute pressure

brachial - pertaining or belonging to the arm

brachiolaria larvae - a starfish larval stage following the bipinnaria stage. It has projecting arms and a developed stomach

Brachiopoda - a phylum of marine invertebrates that superficially resemble bivalve mollusks because of their hinged bilaterally symmetrical shells.They are commonly known as "lampshells"

brachy- - a prefix from the Greek, meaning "short"

Image of brackish estuary

A brackish water area showing a mix of salt and freshwater marsh species in the Weeks Bay National Estuarine Research Reserve, AL. (Photo: NOAA)

brackish - mixed fresh and salt water

bradycardia - an unusually slow heart rate

bradytelic - an exceedingly slow rate of evolution manifested by slowly evolving lineages which survive much longer than would be expected

branchial - pertaining to gills

Image of a nudibranch (sea slug)

The feathery structure toward the posterior of this nudibranch gastropod (marine sea slug) is its respiratory organ.

branchial plume - a respiratory structure or external gills, usually located on the dorsal side toward the posterior of dorid nudibranchs. This plume surrounds the anus and in some species, it may be retracted. The branchial plume is the major respiratory structure in nudibranchs

branching colony - a coral growth pattern where branches are formed

branchiostegal - one of the dermal bony or cartilaginous struts that support the branchiostegal membranes of fishes. Sometimes called branchiostegal rays, but not to be confused with the fin rays

breaker - a wave that approaches shallow water, causing the wave height to exceed the depth of the water, in effect tripping it. The wave changes from a smooth surge in the water to a cresting wave with water tumbling down the front of it; a wave breaking on the shore

breaker zone - the area of a coral reef most exposed to breaking waves

breast - in fishes, the anterior ventral surface under the head

breeding season - the time of the year during which mating occurs

breeding season - that period of a year in which organisms are sexually active

bristles - stiff hairs

brittle star - brittle stars are echinoderms (class Ophiuroidea) which are closely related to sea stars (starfish). They possess radial symmetry with a central body disc from which five highly flexible snake-like arms protrude. There is no replication of internal organs,as in the arms of sea stars, just one set in the central disk. Compared to starfish, brittle stars have a much smaller central disc and no anus. Wastes are eliminated through the mouth, which is situated on the undersideof the disc. The name is derived from their arms breaking off as a means of defense. New arms are easily regenerated. They are also called serpent stars because of the snakelike movements of the five arms

broadcast spawner - an organism that releases gametes directly into the sea for external fertilization

brood - all of the offspring that hatch from a single clutch of eggs or the offspring of a single birth; to incubate eggs

brooder - a coral which harbors or broods developing larvae within its polyps

brooding - the development of larvae within the gastrovascular cavity of an adult coral polyp

brooding - parental care of young

Image of brown algae

Brown algae. (Photo: NOAA)

brown algae - brown algae belong to the Division Phaeophycophyta, whose approximately 1,500 species are almost exclusively marine. They include the largest of the seaweeds and the kelps. The brown algae have chlorophyll a and c, as well as carotenes and xanthophylls, but the green chlorophyll coloration is masked by the brown and yellow pigments. Brown algae are among the largest photosynthetic organisms on earth. The largest kelps may grow to more than 60 meters in length, forming dense underwater forests in colder waters. Many microscopic brown algae grow as epiphytes on underwater vegetation, forming networks of branched filaments, or broad encrustations. All species are multicellular and do not form colonies. Their life cycles are complex, involving alternation of generations. In general, they are not free-floating organisms, but are attached to rock, coral, or other firm surfaces. Sargassum weed, however, is a floating brown algae that stays afloat by producing gas-filled bladders

Image of brown tree snake

The brown tree snake (Boiga irregularis) is an invasive species that has caused great ecological and economic damage on Guam. (Photo: U. S. Geological Survey)

brown tree snake - the mildly venemous brown tree snake (Boiga irregularis) is an introduced species on some Pacific islands that has become a serious pest, especially on Guam. In the absence of natural population controls and with vulnerable prey on Guam, the snakes have become an exceptionally common pest causing major ecological and economic problems. The snakes probably arrived on Guam hidden in ship cargo from the New Guinea area. By 1968, they had dispersed throughout the island and caused havoc by virtually wiping out Guam's native bird species and helped decimate their fruit bat populations. In addition to Guam, brown tree snakes have been sighted on Saipan, Tinian, Rota, Kwajalein, Wake, Oahu, Pohnpei, Okinawa, and Diego Garcia. To date, this snake is not known to be established on any of these islands except Guam

browser - a herbivore that feeds on a variety of plant foods; a software program, such as Netscape Navigator or Microsoft Internet Explorer, that allows one to view pages on the Internet

brunneous - dark brown color

Image of rose-colored bryzoa

Bryzoa colony.

Bryozoa - an animal phylum synonymous with Ectoprocta that contains approximately 5,000 living species. They are all sessile colonial forms composed of zooids. Zooids are tubular, oval or box-like structures that contain a lophophore, which is a circular or horseshoe-shaped fold of the body wall that encircles the mouth and bears numerous ciliated tentacles. Most species form erect or encrusting colonies. They occur in many different habitats, including coral reefs

Image of bubblegum coral

Bubble gum coral on Gulf of Alaska Seamounts. (Photo: NOAA Ocean Explorer )

bubblegum coral - a deep water gorgonian, Paragorgia arborea, found in the North Pacific and North Atlantic Oceans at depths that may exceed 1400m. It can grow to 5m in height and 8 m in width. It is called the bubblegum coral because because it is usually orange or pink in color, and has a lumpy surface texture

buccal - pertaining to the cheek or oral cavity

buccal siphon - in tunicates, the opening through which water enters into the pharyngeal basket. It is also called the incurrent, inhalant, or oral siphon/canal

budding - a type of asexual reproduction in which new individuals develop from the parent organism, forming a swelling similar in appearance to a bud, which separates from the parent as it grows; budding is a form of asexual reproduction in corals where a parent corallite forms daughter corallites

Image of 2 divers

NOAA divers working in buddy pairs. (Photo: NOAA/National Undersea Research Program)

buddy - a scuba diving partner. For safe diving, a pair of divers (buddies) stay close to each other in order to offer assistance if needed

Image of 2 divers sharing air

Scuba divers practicing buddy breathing. (Photo: John Buchanan)

buddy breathing - two scuba divers sharing air from one second stage regulator

buffer - a solution or liquid whose chemical makeup neutralizes acids or bases without a great change in pH

buffer zone - the region near the border of a protected area; a transition zone between areas managed for different objectives

bulbous - a rounded or swollen shape

bullate - describes a blistered or puckered surface

bulliform - blister or boil-shaped

bulwark - the side of a ship above the deck

buoy - a floating platform for navigational purposes or supporting scientific instruments that measure environmental conditions

buoyancy - the tendency of object to float or sink when placed in a liquid. Positively buoyant objects float, negatively buoyant objects sink, and neutrally buoyant objects stay in place

Image of BCD

A buoyancy control devise (BCD). It is a vest-like expandable bladder that can be inflated with air to increase or decrease a scuba diver's buoyancy while diving.

buoyancy control device (BCD) - the BCD is a mandatory piece of equipment for SCUBA diving. It is an expandable bladder, most commonly worn as an expandable vest, that can be inflated with air from the tank to increase buoyancy while diving. To decrease buoyancy, the BCD is deflated through special air-dump valves or hoses. It provides positive buoyancy for resting, swimming or lending assistance to others under water. The BCD allows maintenance of neutral buoyancy at any depth simply by adding or releasing air. It is also called a buoyancy compensator (BC)

burrower - an animal that makes a hole or burrow in the substratum and lives in it. For example, a fidler crab

butterflyfish - any species of colorful, oval-shaped, deep-bodied and strongly compressed spiny-rayed fishes in the family Chaetodontidae. They have small mouths with flexible, brush or comb-like teeth. They resemble the closely related angelfishes. They feed on a variety of foodstuffs from zooplankton to tiny crustaceans and mollusks, soft and hard corals, anemones, segmented worms, and other soft and encrusting invertebrates associated with coral reefs. Some species are omnivores that primarily feed on marine algae as well as animals, while others are obligate corallivores

buttress - see spur and groove

bycatch - organisms taken in a fishery which are not of the species intended for harvest. For example, mammals or turtles captured in trawl or seine fishing

Image of mussel

The byssal gland is located within the foot of the mussel. It produces secretions which are used to form byssal threads for attachment to substrates. (Photo: Great Lakes Sea Grant Network Exotic Species Library, Ontario Ministry of Natural Resources)

byssal thread - one of many thin, hairlike filaments secreted by certain mollusks for attachment to a substrate

byte - a memory and data storage unit composed of contiguous bits, usually eight. For example, file sizes are measured in bytes or megabytes (one million bytes). Bytes contain values of 0 to 255 and most often represent integer numbers or ASCII characters