Fossilized glycolipids reveal past oceanic N2 fixation by heterocystous cyanobacteria.

ABSTRACT: N(2)-fixing cyanobacteria play an essential role in sustaining primary productivity in contemporary oceans and freshwater systems. However, the significance of N(2)-fixing cyanobacteria in past nitrogen cycling is difficult to establish as their preservation potential is relatively poor and specific biological markers are presently lacking. Heterocystous N(2)-fixing cyanobacteria synthesize unique long-chain glycolipids in the cell envelope covering the heterocyst cell to protect the oxygen-sensitive nitrogenase enzyme. We found that these heterocyst glycolipids are remarkably well preserved in (ancient) lacustrine and marine sediments, unambiguously indicating the (past) presence of N(2)-fixing heterocystous cyanobacteria. Analysis of Pleistocene sediments of the eastern Mediterranean Sea

SUBMITTER: Bauersachs T 

PROVIDER: S-EPMC2984197 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature