Research Team: Dr. Emma Gagen, Stefanie Daxer and Prof. Dr. Michael Thomm


DARCLIFE - Cultivation of model Archaea and enrichment of novel benthic Archaea

DARCLIFE is a collaborative research effort between the University of Regensburg, the MARUM Centre at the University of Bremen and the University of North Carolina, funded by the ERC (Project AdvG 247153), aiming to understand Archaea in the deep subseafloor environment. Archaea seem to be major players in these environments (Lipp et al., 2008) however, to date almost all identified Archaea from these biotopes are from deeply branching phylogenetic lineages for which close cultured isolates are not available. As such, little is known about the role of Archaea in the deep subseafloor, the life strategies they employ to enable survival under such low energy conditions and their contribution to element cycling.

In the absence of pure culture representatives, biomarkers (e.g. nucleic acids, lipids) are widely used to detect, identify and monitor microbial populations in nature. In the deep subsurface, analysis of intact polar lipids (IPLs) has recently been developed and employed to investigate microbial activity. These biomarkers are thought to provide information about living microbial cells (Sturt et al. 2004) and insights into microbial metabolism in this environment (Biddle et al. 2006).

Emma Gagen


Stefanie Daxer, Dr. Emma Gagen, Michael Loscar

Here at the University of Regensburg we are cultivating model Archaea under defined conditions (temperature, nitrogen/phosphorus availability, pH etc) in order to examine the relationship between environmental conditions and archaeal IPLs. We are presently cultivating in large scale (up to 300L) three very different Archaea:
(1) Nitrosopumilus maritimus, a mesophilic, ammonia oxidizer
(2) Methanothermobacter thermoautotrophicus, a thermophilic, autotrophic methanogen
(3) Thermococcus kodakarensis, a hyperthermophilic, heterotrophic sulphur reducer
Changes in the membrane lipid composition of these Archaea in response to varied growth conditions are determined by a team of researchers (see below) at the MARUM Centre, University of Bremen.


Additionally, we are attempting to enrich and isolate novel Archaea from subsurface environments, in order to better understand the physiology and metabolic properties of some of the deep-branching archaeal lineages that are frequently detected in the deep subsurface, but which have not yet been cultivated.

Further information can be found at:
http://www.marum.de/en/HinrichsLab_DARCLIFE.html

 

Steffi Daxer
Michael Loscar

Associate researchers:

Prof. Dr. Kai-Uwe Hinrichs (MARUM, Bremen)  
Dr. Travis Meador (MARUM, Bremen)  
Dr. Marcos Yoshinaga (MARUM, Bremen)
Dr. Andreas Teske (University of North Carolina)
Dr. Cassandre Lazar (University of North Carolina)

 


References:

Biddle et al., 2006, Heterotrophic Archaea dominate sedimentary subsurface ecosystems off Peru. Proceedings of the National Academy of Sciences, vol 103 (10), p3846-3851.

Lipp et al., 2008, Significant contribution of Archaea to extant biomass in marine subsurface sediments. Nature, vol 454, p991-994.

Sturt et al., 2006, Intact polar membrane lipids in prokaryotes and sediments deciphered by high-performance liquid chromatography/electronspray ionization multistage mass spectrometry –new biomarkers for biogeochemistry and microbial ecology. Rapid Communications in Mass Spectrometry, vol 18, p617-628.