Environmental Microbiology Team


Structure and FUNctioning of HYdrocarbon polluted microbial MATs



Microbial mats on the hot springs of Yellowstone National Park.
(Credit: Beth Mole)

Microbial mats are exciting complex microbial communities with high capacity to adapt to hostile environments. They are probably the oldest structured ecosystems on earth, since stromatolithes (microfossils of mats) have been dated to be ~3.5 billion years old.
Photosynthetic microbial mats are vertically structured in typically steep gradients of oxygen and sulphide and colonise coastal sediments. They are in an instable equilibrium, characteristically dominated by cyanobacteria and microorganisms linked to sulphur cycle. The different functional groups composing the microbial mats have specific metabolic capacities. They react to each others creating a network of relationship determining the mats’ functioning.

Cross section of thehypersaline microbial mats at Camargue
(Credit: R.Guyoneaud, PUPPA, All Rights Reserved)
The hypersaline microbial mats at Camargue (France)
 (Credit: R.Guyoneaud)

One of the parameters that can alter the ecosystem functioning is the stress induced by a contamination. Contamination affects directly or indirectly different components of the community, because it can be toxic, be a substrate for some bacteria and/or alter the physical and chemical conditions of the environment. Understanding whether the assemblage of microbial mat community is dependent on environmental parameters (such us the level of petroleum contamination) or whether the relationships between members determine this assemblage is the main objective of FUNHYMAT. The ecosystem response to contamination stress can occurs at the community level, the functional group level and the population level.

It is a challenge to understand to which extent contamination will modify ecosystem functioning: the modification of part of the community is reflected in the whole community since the equilibrium between the components is changed.


A microbial mat growing in petroleum polluted sediments

The same microbial mat growing in petroleum polluted sediments... after sediment perturbation

The FUNHYMAT project intends to increase knowledge in the assembly and functioning of microbial mats. The understanding of the functioning of the mats and how the contamination directs their structure are the principal aims of the project.

Project start: 25 September, 2011
Project end: 25 August, 2014