Anaerobic microbes surprise scientists by living with oxygen

Jun 04, 2014 by Aaron Bryans
The stromatolites of Shark Bay are giving researchers insights into microbial interactions. Credit: Robert Young

A study into Shark Bay's microbial mats has detected activity of anaerobic microbes under oxic conditions—highlighting unknown complexities in microbial systems.

The study aimed to provide into past environments and to understand how contribute to by looking into changes in levels of sulphide, iron and phosphate in salt-water stromatolites over 24 hours.

Lead-author Anais Pages from the WA Organic & Isotope Geochemistry Centre at Curtin University, was surprised with the contradictory results.

"We basically showed that [microbial] communities are a lot more complex then what people previously thought and you do have some obligate anaerobic microbes actually living in contact with oxygen," Dr Pages says.

"Usually the microbial mats are very well organised, so you've got the communities organising themselves depending on the light, oxygen and sulphide gradient."

The microbial mats are determined by vertically changing light regimes and interactions between microbial metabolisms and solutes.

Cyanobacteria grow in the upper portion of the mat, with purple-sulfur bacteria just below and anaerobic green-sulfur bacteria near the bottom.

As a result it is expected that sulphide is present at the bottom of while sulphate is apparent at the top.

"You would expect a big difference between day and night because you don't have oxygen being produced at night," Dr Pages says.

"During the day the cyanobacteria will be producing the oxygen through photosynthesis [while] at night there is no light [so] there is no photosynthesis."

The process used colorimetric diffusive equilibration in thin films (DET) and diffusive gradients in thin films (DGT) to measure the co-distributions of sulfide, iron (II) and phosphate.

This video is not supported by your browser at this time.

The techniques unexpectedly showed strong variations in vertical and lateral iron (II) and phosphate distributions, with the changes in being attributed to daily metabolic changes.

Sulphate (SO42-) labelled silver foils were also used to map the distribution of sulphate-reducing activity.

The foils showed an expected result of high sulphate-reduction activity at the top layers, with low activity in the deeper layers.

The study also involved WA scientists Professor Kliti Grice and Michael Vacher, along with interstate authors Dr David Welsh, Professor Peter Teasdale, Dr William Bennett and Pieter Visscher.

Explore further: Model "microecosystems" used to study producer-consumer interaction networks in microbial mats

More information: Anais Pages, David T. Welsh, Peter R. Teasdale, Kliti Grice, Michael Vacher, William W. Bennett, Pieter T. Visscher, "Diel fluctuations in solute distributions and biogeochemical cycling in a hypersaline microbial mat from Shark Bay, WA," Marine Chemistry, Available online 11 May 2014, ISSN 0304-4203, dx.doi.org/10.1016/j.marchem.2014.05.003.

add to favorites email to friend print save as pdf

Related Stories

Novel archaea found in geothermal microbial mats

Nov 21, 2012

(Phys.org)—Our oldest national park may hold answers to questions about the activities of microbial communities that, in turn, may help in developing bioenergy technologies or safely storing carbon dioxide. ...

First Fossil-Makers in Hot Water

Mar 02, 2010

Microbe mats in Yellowstone's hot springs may be living analogs of the primordial microbe communities that constructed the oldest rock fossils on Earth.

Recommended for you

Japanese scientist resigns over stem cell scandal

Dec 19, 2014

A researcher embroiled in a fabrication scandal that has rocked Japan's scientific establishment said Friday she would resign after failing to reproduce results of what was once billed as a ground-breaking study on ...

'Hairclip' protein mechanism explained

Dec 18, 2014

Research led by the Teichmann group on the Wellcome Genome Campus has identified a fundamental mechanism for controlling protein function. Published in the journal Science, the discovery has wide-ranging implications for bi ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.