TY - JOUR
T1 - High pCO2-induced exopolysaccharide-rich ballasted aggregates of planktonic cyanobacteria could explain Paleoproterozoic carbon burial
AU - Kamennaya, Nina A.
AU - Zemla, Marcin
AU - Mahoney, Laura
AU - Chen, Liang
AU - Holman, Elizabeth
AU - Holman, Hoi Ying
AU - Auer, Manfred
AU - Ajo-Franklin, Caroline M.
AU - Jansson, Christer
N1 - Funding Information:
This work was supported by the LDRD project “Biological Carbon Sequestration: Fundamental Research on Biological Carbon Capture and Soil Carbon Stabilization” at Lawrence Berkeley National Laboratory (LBNL), and in part by the Berkeley Synchrotron Infrared Structural Biology (BSISB) Imaging Program through U.S. Department of Energy Contracts DE-AC02-05CH11231 and KP1501021. The microbe-mineral analyses were supported by Center for Nanoscale Control of Geologic CO2 and were carried out at the Molecular Foundry, both of which are funded by the Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under contract no. DE-AC02-05CH11231. M.A. was supported by NIH grant P01GM051487. C.J. was funded in part under the U.S. Department of Energy (DOE) Contract DE-AC05-76RL01830 with Pacific Northwest National Laboratory. This work used the Vincent J. Coates Genomics Sequencing Laboratory at UC Berkeley, supported by NIH S10 Instrumentation Grants S10RR029668 and S10RR027303. We thank Dr. J.A. Cappucchio and Dr. P. Hu for their valuable assistance.
Publisher Copyright:
© 2018, The Author(s).
PY - 2018/12/1
Y1 - 2018/12/1
N2 - The contribution of planktonic cyanobacteria to burial of organic carbon in deep-sea sediments before the emergence of eukaryotic predators ~1.5 Ga has been considered negligible owing to the slow sinking speed of their small cells. However, global, highly positive excursion in carbon isotope values of inorganic carbonates ~2.22–2.06 Ga implies massive organic matter burial that had to be linked to oceanic cyanobacteria. Here to elucidate that link, we experiment with unicellular planktonic cyanobacteria acclimated to high partial CO2 pressure (pCO2) representative of the early Paleoproterozoic. We find that high pCO2 boosts generation of acidic extracellular polysaccharides (EPS) that adsorb Ca and Mg cations, support mineralization, and aggregate cells to form ballasted particles. The down flux of such self-assembled cyanobacterial aggregates would decouple the oxygenic photosynthesis from oxidative respiration at the ocean scale, drive export of organic matter from surface to deep ocean and sustain oxygenation of the planetary surface.
AB - The contribution of planktonic cyanobacteria to burial of organic carbon in deep-sea sediments before the emergence of eukaryotic predators ~1.5 Ga has been considered negligible owing to the slow sinking speed of their small cells. However, global, highly positive excursion in carbon isotope values of inorganic carbonates ~2.22–2.06 Ga implies massive organic matter burial that had to be linked to oceanic cyanobacteria. Here to elucidate that link, we experiment with unicellular planktonic cyanobacteria acclimated to high partial CO2 pressure (pCO2) representative of the early Paleoproterozoic. We find that high pCO2 boosts generation of acidic extracellular polysaccharides (EPS) that adsorb Ca and Mg cations, support mineralization, and aggregate cells to form ballasted particles. The down flux of such self-assembled cyanobacterial aggregates would decouple the oxygenic photosynthesis from oxidative respiration at the ocean scale, drive export of organic matter from surface to deep ocean and sustain oxygenation of the planetary surface.
UR - http://www.scopus.com/inward/record.url?scp=85056571604&partnerID=8YFLogxK
U2 - 10.1038/s41467-018-04588-9
DO - 10.1038/s41467-018-04588-9
M3 - Article
AN - SCOPUS:85056571604
VL - 9
JO - Nature Communications
JF - Nature Communications
SN - 2041-1723
IS - 1
M1 - 2116
ER -