21 August 2018

Ancient porphyrins indicate far earlier date for photosynthesis

Identification of two classes of Ni- and VO-porphyrins by FT-ICR MS. Identification of two classes of Ni- and VO-porphyrins by FT-ICR MS.

Molecular fossils of chlorophyll (called porphyrins) more than 1.1 billion years old find suggest that photosynthesis began 600 million years earlier than previously established.

What did scientists discover?

Researchers discovered intact porphyrin molecules in ocean rock that was measured to be 1.1 billion years old, which indicates that bacteria dominated life in the ocean at that time.

THE TOOLS THEY USED

This research was conducted in the 9.4 Tesla FT-ICR MS (Passively Shielded) at the MagLab's ICR Facility.

Why is this important?

The oceans of Earth's middle age, 1.8–0.8 billion years ago, were devoid of animal-like life. One hypothesis is that the emergence of large, active organisms was restrained by the limited supply of large food particles, such as algae.

Through discovery of molecular fossils of the photopigment chlorophyll in 1.1-billion-year-old marine sedimentary rocks, scientists were able to quantify the abundance of different phototrophs. The nitrogen isotopic values of the fossil pigments showed that the oceans were dominated by cyanobacteria, while larger planktonic algae were scarce. This supports the hypothesis that small cells at the base of the food chain limited the flow of energy to higher trophic levels, potentially retarding the emergence of large and complex life. Understanding the evolution of life on Earth helps us to understand and predict the impact of natural and human-generated changes to our ocean ecosystems.

Who did the research?

N. Gueneli1, A.M. McKenna2, N. Ohkouchi3, C.J. Boreham4, J. Beghin5, E.J. Javaux5, J.J. Brocks1

1The Australian National University; 2Ion Cyclotron Resonance Facility, National MagLab; 3Japan Agency for Marine-Earth Science and Technology; 4Geoscience Australia; 5University of Liège, Belgium

Why did they need the MagLab?

The research required the ultrahigh mass resolving power and mass measurement accuracy of the MagLab’s Fourier Transform Ion Cyclotron Resonance mass spectrometer to identify porphyrins, the key molecules in the study, in a mixture of tens of thousands of other compounds present in the ancient ocean rock.

Details for scientists

Funding

This research was funded by the following grants: G.S. Boebinger (NSF DMR-1157490); J.J. Brocks, Australian Research Council (DP1095247, DP160100607); E.J. Javaux, European Research Council (ELiTE FP7/308047)


For more information, contact Amy McKenna.

Details

  • Research Area: Geochemistry
  • Research Initiatives: Life
  • Facility / Program: ICR
  • Year: 2018
Last modified on 22 August 2018