Bugs Alive!

Scientists have discovered that water is teeming with literally  thousands more microscopic creatures than previously thought - many of them still largely unknown. "Only about one in ten water-borne bacteria have even been identified," says Daniel Hoefel, of the Cooperative Research Centre for Water Quality and Treatment in Australia. "There are several million species which we know by name, but the vast number of creatures that live in our water are still unknown - we haven't named them, described them, or discovered anything about their behaviour."
  According to Hoefel, this is about to change. Some ingenious lateral thinking has given water researchers a novel high-speed means of coming to grips with the teeming microbes. "The main reason that we haven't been able to identify all these microbes is that they are very hard to grow in a laboratory culture," he says.
  Hoefel and his colleagues at the Australian Water Quality Centre, in conjunction with the University of South Australia, had the idea of using a piece of hospital equipment known as a flow cytometer to assess water quality. A flow cytometer has until now mainly been used for examining human and animal blood cells, says Hoefel. "We found that by applying a stain to water samples, the active bacteria glow under the laser beam of the flow cytometer, and each individual cell is counted as it passes through the beam," he says. "This means that we can count up to a thousand bacterial cells per second," says Hoefel. "We can take a sample, treat it with the dye or stain, count hundreds of thousands of bacteria, and have a result within an hour of receiving the sample."
 "Now we can assess whether the process is removing and inactivating all of the bacteria, not just those that are culturable; in other words, we can now accurately monitor the efficiency of water treatment plants and understand the challenges involved in water treatment in a way which was not previously possible." "We have also found that the water treatment processes currently being used in Australia are effective in removing or inactivating bacteria", he said. "The benefit of our new technique is that it is easier to use and more accurate for monitoring the status of our water supplies to our treatment facilities".
  Hoefel hopes that due to the convenience and accuracy of the new test it can be adopted in parts of the world where water quality monitoring has previously been difficult. "Portable in-field flow cytometers have recently been developed," says Hoefel, "but in most cases a sample can readily be sent to a laboratory for assessment." "Apart from the flow cytometer, the actual assay itself doesn't require any special equipment other than a few pipettes for working with each sample," he says.

Read the Chymical Wedding List - bonus feature in Issue 71 of Elemental Discoveries; we've also got a new feature listing the elemental discoveries timeline.