Exam 21: Nutrient Cycles

Mercury-resistant bacteria detoxify mercury by producing Hg⁰.

The burning of fossil fuels produces significant amounts of

When carbon is limiting in a system, sulfate reducers often predominate the system when sufficient sulfate ions are present for reduction.

Climate scientists are developing methane hydrates to decrease the effects of global warming.

The precipitation of soluble iron ions (Fe²⁺ and Fe³⁺) into solid iron occurs spontaneously in the presence of organic carbon compounds.

Microbial activity generates methylmercury, which is much less toxic than the mercuric ion.

Methanogens, among other compounds, use alcohols and fatty acids to synthesize methane gas in anoxic environments.

Frozen methane molecules are called

Which compound in fertilizer do farmers use to inhibit the production of easily leached nitrogen compounds?

Denitrification of fertilizer can result in harmful algal blooms.

Some bacteria have genes that confer resistance to mercury.

More carbon is present in dead organic material on Earth than in living organisms.

Lignin is a complex polymer of methoxylated ________ compounds and is present in ________.

Using the sudden bloom of cyanobacteria in a lake due to anthropogenic fertilizer inputs as an example, explain the coupling of carbon, nitrogen, and oxygen cycling. Exclude discussion of all organisms other than microorganisms.

Coccolithophores and foraminiferans both use ________ to form their exoskeletons.

Which organisms form the foundation of the carbon cycle?

In the natural carbon cycle, carbon dioxide is returned to the atmosphere by the respiration of animals and chemoorganotrophic microorganisms.

Which of the following processes does denitrification contribute to?

What is a characteristic of a deep sea marine cold seep/vent?

Agricultural application of nitrogen fertilizer