Part 3 - Molecular Geobiology Flashcards
(11 cards)
summarize the importance of cholesterol in bacteria and provide this specific name and its relevance to geobiology.
Provides stability
Sterols in Eukaraya
Hopanols in eubacteria.
Sterols will change most during diagnosis, but hopane not so much; only the disappearance of 4 OH.
in the Archea there were huge long lipids used as biomarkers.
What happened before the neoproterozoic oxygenation event?
There was a rise in eukaryotes and bacteria (steranes/hopanes) and, a rise in the diversity of steranes between the Sturtian glaciations.
“Rise of algae”
What molecule is consistent with animal origin?
Monoaromatic steroids.
What does the diagenesis of porphyrins indicate?
When magnesium of the porphyrin is replaced by vanadyl, it is indicative of chlorophyll. The oldest extracted was 1.1 bya.
What can you use to discriminate orgin of fossil porphyrins?
You can use N - isotopes, which are said to support cyanobacteria chlorophyll.
What can be said about the hopanes /steranes found in 2.7 drillcore rock?
Some detected steranes from the archean rock, however, the organic matter was cooked and came from contamination.
What is the oldest biomarker, what age, etc?
Comes from purple-green sulfur bacteria, which has the oldest Oh preserved in earth.
Important primary producer and lived in sulfur-rich envr.
primary production was driven by this. may explain delayed oxygenation.
Toxic for eukaryotes.
What are the main pathways for kerogen formation, and what are we most interested in and why?
There are two main ways kerogen can form:
Selective Preservation: Certain biopolymers (building blocks of life) are preserved over time, becoming part of the kerogen structure.
Degradation-Recondensation: Organic molecules break down and then recombine to form new, more stable compounds that makeup kerogen.
We can see thermochemolysate using Gas Chromatography-Mass Spectrometry (GC-MS).
we can see metals in organic matter using XRF
We are most interested in the lignin biopolymer, which evolved to be found in euphyllophytes and lycophytes.
it is abundant and found in biofuel.
What does this indicate?
lignin in fossil plants.
What can be used to identify wall biopolymers in biopolymer microfossils and what was found?
FT infrared spectroscopy (Fourier Transform Infrared (FT-IR) spectroscopy).
was found that acritarchs
was found that
What is this image conveying?
Sporopollenin: This is a highly resistant biopolymer that forms the outer layer of pollen grains and spores. It is known for its ability to survive extreme conditions and fossilization processes.
Silurian Cryptospores: These are microscopic fossils of early land plants.
IR Spectroscopy: This technique analyzes the interaction of infrared light with a sample to identify specific chemical bonds.
The image shows:
Chemical structure of sporopollenin: It highlights the presence of aromatic rings and various functional groups within the sporopollenin molecule.
IR spectra of different samples: The spectra of a Leiosphere, Chitinozoan, and Pachytetras rugosa are compared.
Identification of the 1502 cm-1 band: This band is characteristic of the aromatic rings in sporopollenin. It is present in the spectra of the cryptospores, indicating the presence of sporopollenin in these ancient fossils.
Conclusion:
The presence of the 1502 cm-1 band in the IR spectra of Silurian cryptospores provides strong evidence for the existence of sporopollenin in these early land plants. This finding has significant implications for understanding the evolution of land plants and the development of terrestrial ecosystems.
