The Definitions of Some of Our Favourite Words

The meanings of the more idiomatic terms related to the work we do at Biologica can be found here. If there is a term you don’t understand, let us know and we’ll add it to the list!

  • Abundance

    The total number of organisms present

  • Benthos

    The community of organisms that live on or in the bottom sediments of a sea, lake, or other body of water.

  • B-IBI

    Benthic Index of Biotic Integrity, is a quantitative method for determining and comparing the biological condition of streams.

  • Biomass

    A measurement of an organism’s (or group or organisms’) mass.

  • Bogorov Tray

    A clear rectangular tray with a channel cut into it enabling the quantitative sorting of organisms.


    Canadian Aquatic Biomonitoring Network, is an aquatic biomonitoring program for assessing the health of freshwater ecosystems in Canada.

  • Caton Tray

    A subsampling device that consists of a sieve of desired mesh size (commonly 250 or 500um) that is secured to the base of a plastic or metal tray, and split into 6, 12, or 24 quadrats. Marine or freshwater benthic samples that have been screened are placed in the tray and the sample is spread evenly across the surface. Quadrats are sorted until a desired target count is reached.

  • Chain of Custody (COC)

    Documentation detailing sample identification, description, transfer details, handling instructions, and analysis instructions.

  • Colonial Organism

    An organism composed of multiple constituent organisms that live in close association to, or connected with, one another.


  • Dichotomous (branching) Key

    A reference tool wherein a series of choices among/between features leads progressively towards identification of an organism.

  • Environmental Impact Assessment (EIA)

    The process by which the anticipated effects on the environment of a proposed development or project are measured. If the likely effects are unacceptable, design measures or other relevant mitigation measures can be taken to reduce or avoid those effects.

  • Environmental Risk Assessment (ERA)

    A process for estimating the likelihood or probability of an adverse outcome or event due to pressures or changes in environmental conditions resulting from human activities.

  • Epifauna

    Benthic animals that live on the surface of a submerged substrate, such as a riverbed or seabed (as opposed to “infauna”).

  • Food Chain/Web

    A simplified way to show the relationships among organisms based on their feeding strategies.

  • Formalin

    A mixture of formaldehyde and water.

  • Genus

    A group of closely-related species.

  • Heterotrophic

    A feeding strategy wherein an organism must consume organic substances (usually plant or animal matter) for energy.

  • Ichthyoplankton

    The eggs and larvae of fish.

  • Infauna

    Benthic animals that live and burrow within the a submerged substrate (as opposed to “epifauna”)

  • Intertidal

    The area of a seashore that is submerged at high tide and exposed at low tide.

  • Invasive Species

    Organisms not native to a particular region and potentially disruptive to the native ecosystem.


  • Invertebrate

    Animals without a spine (backbone).

  • LPL (Lowest Practicable Level)

    The most specific level of taxonomic identification possible.  This will vary depending regionally and by group, however it is frequently genus or species.

  • Lugol’s iodine solution

    A dark brown liquid that is used to preserve algal cells in water samples.

  • Macroinvertebrate

    Invertebrates visible to the naked eye.

  • Macrophyte

    Aquatic plant life visible to the naked eye (photosynthetic) composed of multiple cells per organism.

  • Marchant Box

    A subsampling device that consists of a plastic box with 100 cells, 27x27x15cm, and has a water tight lid. Freshwater benthic samples that have been screened are placed into this box and debris is evenly spread across all cells. Debris is sorted from each cell until a desired target count is reached.

  • Meiofauna

    Microscopic organisms that live in the space among individual sediment particles in aquatic sediments or soil.

  • Periphyton

    Freshwater organisms (typically algal) attached to plants or other objects projecting above the bottom of a waterbody.

  • Phytoplankton

    Photosynthesizing microscopic organisms that inhabit the upper sunlit layer of almost all oceans and bodies of fresh water. Sometimes referred to as “microalgae”.

  • Plankton

    A diverse group of organisms that live suspended in the water column bodies of water and cannot swim against a current.

  • Replicate

    One of several samples taken from the same location at the same time.

  • Sample

    A discrete unit of material collected in the field to be analyzed at Biologica.

  • Species

    A group of individuals or populations that are similar in structure and physiology and are capable of interbreeding and producing fertile offspring, and that are different in structure and/or physiology from other such groups and normally do not interbreed with them.

  • Species Richness

    Total number of different species in a sample.

  • Subspecies

    A subdivision of a species, usually a geographic race.  The different subspecies of a species ordinarily are not sharply differentiated.  They intergrade with one another and are capable of interbreeding.

  • Sub-sampling

    Fractioning of a sample into multiple smaller units that are representative of the entire sample.

  • Subtidal

    The benthic ocean environment below low tide that is always covered by water.

  • Taxon

    A group of organisms classified together.

  • Taxonomy

    The process of identifying living things, describing relationships among them, and thereby grouping them according to common characteristics.

  • Quality Assurance (QA) and Quality control (QC)

    A system for verifying and maintaining the desired level of quality in the data produced by reviewing all factors involved in its assembly, including the enumeration and identification of organisms in a sample.

  • Zooplankton

    Heterotrophic (feeding on other organisms) animals that live all or part of their life as plankton.

For more information on taxonomic analysis, please consult our Services page.

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