diff --git a/cyanobacteria.md b/cyanobacteria.md
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--- a/cyanobacteria.md
+++ b/cyanobacteria.md
@@ -1,6 +1,10 @@
 # Cyanobacteria
 
-- Responsible for The Great Oxygenation
+- Responsible for [[The Great Oxygenation]]
 - [[Spirulina]]: Highly nutritious
 - [[Rivularia]]: Classifies as multi-cellular, as it can regrow its
 photosynthetic filament
+
+[//begin]: # "Autogenerated link references for markdown compatibility"
+[The Great Oxygenation]: the-great-oxygenation "The Great Oxygenation"
+[//end]: # "Autogenerated link references"
diff --git a/the-great-oxygenation.md b/the-great-oxygenation.md
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+# The Great Oxygenation
+
+- The diverity of [[bacteria]] exploded during the [[Archaean]], leading to the
+evolution of [[Cyanobacteria]]
+  - This does not mean that [[Spirulina]] existed during the [[Archaean]]: it
+  is a modern organism
+- There was almost no O₂ in the atmosphere before the
+[[Archaean]]-[[Proterozoic]] break
+  - No O₂ means no formation of peroxides
+  - Peroxides are dangerous to many cells as they rob electrons from
+  proteins, fatally altering them
+- Cells had to develop anti-oxidation defenses, including [[catalase]]
+- Cells had two ways to adapt to O₂
+  1. Become a strict anaerobe, and avoid oxygen-containing habitats
+  2. Tolerate O₂
+     - O₂ toleration can easily lead to aerobic metabolism
+
+[//begin]: # "Autogenerated link references for markdown compatibility"
+[bacteria]: bacteria "Bacteria"
+[Archaean]: archaean "Archaean"
+[Cyanobacteria]: cyanobacteria "Cyanobacteria"
+[Proterozoic]: proterozoic "Proterozoic"
+[//end]: # "Autogenerated link references"