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Caddisfly (order Trichoptera), a macroinvertebrate used as an indicator of water quality. [1] A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. [2]
Penicillium species, Aspergillus niger and Candida albicans are used in the pharmaceutical industry for microbial limit testing, bioburden assessment, method validation, antimicrobial challenge tests, and quality control testing. [11] When used in this capacity, Penicillium and A. niger are compendial mold indicator organisms. [11]
Indicator bacteria can be cultured on media which are specifically formulated to allow the growth of the species of interest and inhibit growth of other organisms. Typically, environmental water samples are filtered through membranes with small pore sizes and then the membrane is placed onto a selective agar.
Then an identification key is used to help determine which category or group the organism belongs in and allows a numerical value be assigned to that organism. A worksheet is then used to calculate the final value or score of all the organisms found. Depending upon the worksheet's equations, the score determines the condition of the water quality.
A plant's indicator status is applied to the species as a whole however individual variations may exist within the species, referred to as "ecotypes"; individual plants which may have adapted to specific environments as may occur in a microhabitat, which isn't indicative of the species as a whole. The morphological differences between these ...
Using neutral red pH indicator, the agar distinguishes those gram-negative bacteria that can ferment the sugar lactose (Lac+) from those that cannot (Lac-). This medium is also known as an "indicator medium" and a "low selective medium". Presence of bile salts inhibits swarming by Proteus species.
The presence or lack of macroinvertebrates such as insects, worms and snails in a river or stream can give a biological indicator on the health of that waterway. [2] The MCI assigns a number to each species of macroinvertebrate based on the sensitivity of that species to pollution. The index then calculates an average score. [1]
Two-way indicator species analysis (TWINSPAN) is a Fortran-based statistical analysis method described in 1979 by Mark O. Hill. [1] It is widely used in ecological research. [ 2 ] As of 1997, it was the only widespread standardized method to identify indicator plants.