Life in Thiobiotic Habitats Flashcards
Why is H2S harmful to metazoans?
+It is a neurotoxin that affects pulmonary function in vertebrates.
+It poisons aerobic respiration by binding to the cytochrome oxidase system.
+It binds to methaemoglobin.
How do meiofauna adapt to thiobiotic conditions?
Adaptions include H2S and HCN-insensitive cytochrome-o, sulphur-reducing symbionts, impermeable outer layers and sulphur detoxification mechanisms.
What is unusual about the variation in levels of sulphur binding proteins in vent clams with respect to distance from a vent.
The concentration of sulphide-binding proteins increases in clams with increasing distance from the vent, so that they can extract enough sulphides for their symbionts as the external sulphide concentration falls as the vent plume is diluted.
What is the significance of finding the RuBisCo enzyme in a metazoan animal?
It is the key enzyme in the Calvin-Benson carbon fixation cycle that is only found in plants and chemoautotrophic bacteria and other potential microbial symbionts.
How do chemoautotrophs use H2S?
As an alternative to oxygen as an electron acceptor.
What is the Redox Discontinuity Zone (RDZ)?
The start of the anoxic zone, where the sulphur biome starts.
