Diversität von Mikroeukaryonten in anoxischen marinen Lebensräumen
Final Report Abstract
The major findings that emerged from this projects are: (i) Anoxia is a highly selective environmental factor relating protistan communities. Protitan communities in oxygen‐ depleted environments are more diverse (and divergent to previously described protists) compared to protistan communities in normoxic waters. This identifies anoxic habitats as very promising targets for the discovery of novel diversity. Furthermore, our data data suggest that in protists, the similarity in the SSU rRNA gene correlates with phenotypic similarities as a result of environmental selection. (ii) Protistan communities are characterized by a degree of low‐abundant populations that compares to bacterial and archaeal communities. Applying a new pyrosequencing protocol, developed for protist in the framework of this funded project, to marine plankton assemblages, we could show that protistan communities are one to two orders of magnitude more complex than suggested by previous clone library studies. This new protocol allows for much deeper insights into the true extent of protistan diversity and to study the genomic potential of protistan communities to react to environmental changes, specifically in light of climate change and ocean acidification. (iii) We found that in marine systems the consideration of local shifts in protistan community structures over time is significant and offers additional information for diversity surveys, and can considerably contribute to the revelation of spatial protistan community patterns. (iv) In a proof‐of‐concept study, we succeeded to develop a reproducible protocol for generating a eukaryote environmental meta‐transcriptome and a software pipeline to process the massive sequence data included in such a meta‐transcriptome. This strategy will be useful in future studies in order to analyze the physiological adaptations of extremophile protistan communities to environmental conditions that define the limits of eukaryote life and to study the environmental selection processes generating diversity. (v) We succeeded to isolate a number of organisms of anoxic marine habitats, one of which (a pucciniomycote fungus) emerged as specifically interesting because of its anaerobic denitrification capability and its presumptive ancient and isolated evolutionary history. In order to unlock the secrets of this novel organism the mitochondrial as well as the nuclear genome will be subjected to sequencing.
Publications
- (2009) Massively parallel tag sequencing reveals the complexity of anaerobic marine protistan communities. BMC Biology 7:72
Stoeck T, Behnke A, Christen R, Amaral‐Zettler L, Rodriguez‐Mora MJ, Chistoserdov A, Orsi W, Edgcomb VP
- (2010) Fungal diversity in oxygen‐depleted regions of the Arabian Sea revealed by targeted environmental sequencing combined with cultivation. FEMS Microbiology Ecology
Jebaraj CS, Raghukumar C, Behnke A, Stoeck T
(See online at https://doi.org/10.1111/j.1574-6941.2009.00804.x) - (2010) Multiple marker parallel tag environmental DNA sequencing reveals a highly complex eukaryotic community in marine anoxic water. Molecular Ecology, 19:2131
Stoeck T, Bass D, Nebel M, Christen R, Jones MDM, Breiner HW, Richards TA
- (2010) Spatio‐temporal variations in protistan communities along an O2/H2S gradient in the anoxic Framvaren Fjord (Norway). FEMS Microbiology Ecology 72:89102
Behnke A, Bunge J, Barger K, Stoeck T
