Understanding Stable Sulfur Isotopes

What distinguishes stable sulfur isotopes from each other?

• Different number of electrons

• Different number of atoms

• Different number of neutrons

• Different number of protons

Why are sulfur-34 and sulfur-32 commonly used to measure isotope ratios?

• They are the least reactive isotopes

• They are the heaviest isotopes

• They are the most abundant isotopes

• They have the same number of neutrons

What role do sulfate-reducing bacteria play in sulfide biosynthesis?

• They convert sulfide to sulfate

• They produce sulfide by consuming sulfate

• They oxidize sulfide to sulfur

• They reduce sulfur to sulfide

How does the presence of sulfate-reducing bacteria affect sulfur isotopic composition?

• They do not affect isotopic composition

• They produce isotopically heavy sulfide

• They produce isotopically neutral sulfide

• They produce isotopically light sulfide

What does the isotopic composition of sedimentary sulfides indicate about early Earth?

• High oxygen levels

• Low sulfate concentrations

• Stable climate conditions

• Abundant volcanic activity

What is the significance of the Great Oxidation Event in relation to sulfur isotopes?

• It increased sulfur isotope fractionation

• It decreased sulfur isotope fractionation

• It eliminated sulfur isotopes

• It had no effect on sulfur isotopes

What is mass-independent fractionation (MIF) in sulfur isotopes?

• Fractionation that depends on pressure

• Fractionation that depends on temperature

• Fractionation that is independent of mass

• Fractionation that depends on mass

How does UV radiation affect sulfur isotopes in the atmosphere?

• It causes mass-independent fractionation

• It has no effect on sulfur isotopes

• It causes mass-dependent fractionation

• It stabilizes sulfur isotopes

What happens to sulfur isotopes in an oxic atmosphere?

• They disappear completely

• They become more abundant

• They remain unchanged

• They recombine with oxygen

What can sulfur isotopes be used as proxies for?

• Volcanic eruptions

• Ancient life and sulfate evolution

• Modern climate change

• Ocean currents