Dr. Patricia Sanchez-Baracaldo is from the School of Geographical Sciences at the University Bristol. Rather than paraphrase what is already so nicely stated on her of website, I'll just post it here:"My research aims to understand how cyanobacteria (also known as blue-green algae) have contributed to global nutrient cycles (e.g., nitrogen, carbon, oxygen) through geological time. The timing of diversification of some marine cyanobacteria lineages suggests that cyanobacteria have played a key role in regulating the global environment and past climatic events. By studying cyanobacteria evolution my lab aims to understand how these organisms contributed to making our planet increasingly habitable during the early Earth."Highlights from the talk:
- Nitrogen is underappreciated in it's role in making our planet habitable.
Check out Patricia's work from 2014 and 2015 which were featured in the presentation:
- A neoproterozoic transition in the marine nitrogen cycle...
- Origin of marine planktonic cyanobacteria...
By volume our dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide and other gases (internet encyclopedia extraordinaire - Wikipedia).
- The oxygen in our atmosphere is all the result of biological activity...namely Cyanos!
- The first 'reliable' fossils of cyanobacteria don't appear until after the great oxidation event (Jennifer Glass' ASM presentation touched on GOE) around 1.9 Ga.
- However, genomic studies put the relatives of modern cyanobacteria appearing at 2.3-2.5 Ga and that these relatives were isolated from freshwater and land environments. From there they moved into marine environments at different times in history. This implies that marine groups evolved much later...which means...There were no cyanobacteria in the Archean ocean! So perhaps this was why oxygenation came later, because the organisms creating our oxygen atmosphere did not move into the oceans until later.
Interesting aside... it has been historically thought that the most abundant nitrogen fixing bacteria in the ocean was the photosynthetic cyanobacteria but a recent study came out that may topple cyano dominance in terms of nitrogen fixation in the ocean; and these bugs are not photosynthetic.
and here's the link to this 'large scale study'...
Back to cyanos...
- So marine groups are thought to have diverged from freshwater groups during the Neoproterozoic (see her publication linked above) and these planktonic groups had a major impact on global biogeochemical cycles of carbon, nitrogen and oxygen.
For a nice article on cyanobacteria and the origins of photosynthesis also check out the Science Report from the Hugenholtz Lab and Blankenship's 2017 article "How Cyanobacteria went Green" (pay-walled, bugger - but if you have a subscription or access check it out).
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| http://www.scifiideas.com/science-2/sciency-words-oxygen-catastrophe/ |
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