Daphnia: Indicators of Environmental Health

In February I attended a seminar given by Professor John Colbourne on daphnia and how they might be used as indicator species to determine the presence of toxins in water sources. Daphnia are a genus of small planktonic crustaceans normally around 1-5mm in length, they are often more commonly known as water fleas and typically inhabit aquatic environments such as swamps, lakes, ponds, rivers and streams.

A species of the Daphnia genus

Professor John Colbourne works for Birmingham University where he holds the Chair of Environmental Genomics and is a founding member of the Daphnia Genomics Consortium (DGC).

The talk led off with a description of the current problem in California where tap water, despite satisfying the safe water drinking act is severally off colour and clearly contaminated with something we probably shouldn’t be drinking.

Our tap water typically contains around 60,000 chemicals, of which only 7% have been tested for their toxicity in humans, on top of this we also don’t know whether mixtures of certain chemicals could create toxins.

Tox21 is the initiative which was set up by pooling resources from several environmental and health organisations in order to screen thousands of chemicals to predict potential toxicity. As well as testing on mammals and using in-vitro cell-based assays the scheme also uses alternative animal testing on species such as daphnia, this greatly increases the amount of tests that can be done in the same amount of time than would be achieved using other study methods.

The talk was however, focused on the subject of environmental health and how daphnia can be an indicator of this by cataloging the effects of compounds on gene responses. By taking a water sample that includes daphnia, the RNA can be extracted from the organism which can allow the detection of certain compounds present in the water sample.

I found this talk extremely interesting as it highlighted a novel way to assess environmental health and ensure water is fit for human consumption. John also posed a challenge to the UK to improve the understanding of the function of daphnia genes and to understand model systems of environmental health.

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