6 December 1996 Probing origins of life on Earth

Did building blocks for earthly life – membranous material for cell walls and nutrients for the first microorganisms – arrive from outer space by meteorite?

That's a theory being explored by scientists at Lincoln University, New Zealand, in conjunction with a colleague at the University of California, Santa Cruz, USA.

Dr Michael Mautner and Dr Bob Leonard of Lincoln and Professor David Deamer of the United States believe that in Earth's early days meteorite and interplanetary dust particles containing trapped organic material would have landed in the ocean and eventually encountered undersea volcanoes and hydrothermal vents which would have heated and pressurised them to the point of releasing components capable of nourishing microbes.

Furthermore they believe the released material and some of its components had a membrane forming ability, and here's the origins of life connection because membranes would have been essential for the formation of early cells, to separate the living material from the surrounding solution and to allow the concentrated solutions required for biological processes.

In answer to the question, could extraterrestrial materials have provided nutrients for early life forms, tests in the Department of Soil Science at Lincoln University conducted by Dr Mautner and Dr Leonard have shown that in meteorite extracts populations of the common environmental microorganism Flavobacterium orzyihabitans and the soil microorganism Pseudomonas maltophilia grew larger by factors of 10 to 1000 compared with controls in pure water.

The Lincoln studies showed that microorganisms can indeed metabolise organic substances from extraterrestrial material, however the scientists involved stress that to extend their observations to early evolution they need to know if the meteorite organics can support primitive microorganisms called archaebacteria, which are the most representative living examples of early life.

Among the exciting implications of the findings is that similar materials on asteroids and other planetary bodies may serve as nutrients for earthly microorganisms transported there by design or accident. With a nutrient supply "out there" Earth could "seed" other planetary systems with its own microorganisms thus lifting life here to cosmic proportions" says Dr Mautner.

Furthermore, microbial conversion to biomass may be useful to process asteroid materials as a proposed organic resource for space settlements, he says.

Ian Collins, Journalist, Lincoln University, Canterbury, New Zealand.