MARA ecotoxicity test

MARA is an ecotoxicity test that includes 11 different species of microorganisms. It assesses toxicity by measuring their growth in the presence of the sample.  MARA offers a more genetically diverse alternative to ecotoxicity testing using a single species of bacteria, and includes marine, freshwater and terrestrial species of bacteria as well as one yeast species. 

photo of LumiMARA microbial ecotoxicology test kit including three reagent bottles, a box of lumimara strains and two vials of lumiMARA strains

Ecotoxicology testing

Ecotoxicology testing gives an insight into the impact that chemicals or industrial effluents could have on the environment. It can also be a useful tool for assessing sites or environmental samples for the presence of toxic compounds. Testing involves exposing living organisms to samples and assessing the effect. Living organisms commonly used for testing can include bacteria, algae, crustacea and fish.

Benefits of bacteria for ecotoxicology testing

Bacteria have a number of benefits for ecotoxicity testing compared to higher order organisms:

  1. Convenient format: bacteria are small and easy to handle in large numbers, so for example, testing can be carried out in a test tube or microtiter plate.
  2. Fast: bacteria grow and respond quickly to the presence of toxins, so test results can be obtained quickly.
  3. No ethical issues: testing with microorganisms has none of the ethical issues associated with testing with higher order organisms such as fish.

MARA includes ten species of bacteria and one species of yeast.

The use of bacterial bioassays to assess toxicity is well established, with single species bacterial tests described in ISO 11348-3:2007. However, microorganisms are a highly diverse group of living things and this diversity is crucial for maintaining a healthy ecosystem. Testing with multiple strains of microorganisms is easy with the MARA ecotoxicity test and gives much more information on the toxicity of a substance than testing with a single marine strain.

Marine, freshwater and terrestrial species of bacteria in one test

Ecotoxicity testing with bacteria is often based on a single strain of the marine species Aliivibrio fischeri (previously Vibrio fischeri). However MARA includes not only strains of marine bacteria, but also freshwater and terrestrial strains. Ecotoxicity with MARA therefore gives results more representative of a range of different environments and groups of organisms.

Test with bacteria and yeast

MARA includes a yeast species in addition to ten different species of bacteria. Like bacteria, yeasts can be grown quickly in a microtiter plate, but as eukaryotes, they share many biological properties with higher order organisms.  This combination makes yeasts an excellent model organisms for the study of eukaryotes. 

Application in the oil and gas industry

The Oslo and Paris Commission (OSPAR) Recommendation 2012/5 requires contracting parties, of which the UK is one, to implement a risk-based approach for the management of produced water from offshore oil and gas installations. NCIMB’s MARA and LumiMARA bioassays are recommended by the UK’s Department of Business, Energy and Industrial Strategy (BEIS), as part of their preferred approach to achieving this. 

Want to find out more?

We provide an ecotoxicity testing service at our Aberdeen laboratories. Please contact us for more information about the service or to request a quote.

You might also be interested in:

LumiMARA pdf
UK RBA program
Contact NCIMB


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