Following the Deepwater Horizon Accident in the Gulf of Mexico

question 1

Multiple Choice

Following the Deepwater Horizon accident in the Gulf of Mexico in 2010, bioremediation was used to eliminate much of the oil from the contaminated water. To encourage the growth of oil-degrading microbes, "fertilizer" including iron and nitrogen was added to the water. Which of the following
Statements regarding the growth of these microbes is incorrect?

• A) The oil-degrading microbes used oil (hydrocarbons) as their carbon source.
• B) Large amounts of iron were needed, as iron is a macronutrient for oil-degrading microbes.
• C) Nitrogen gas (N2) present in air is not in a form that can be used by oil- degrading microbes.
• D) The concentration of sulfate in the Gulf of Mexico is su?cient for the growth of oil- degrading microbes.

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Definitions:

Parallelism

The extent to which the friction surface of a brake disc varies in thickness. Slight variations in rotor thickness result in brake pedal pulsation as the pads must move in and out to compensate. Also called taper or thickness variation.

Runout

The degree of wobble or deviation from true circular rotation often related to rotors or wheels.

Rotor Parallelism

The degree to which both sides of a brake rotor are equidistant to each other, essential for smooth braking.

Micrometer

A precision measuring instrument used to measure very small distances, thicknesses, or diameters with high accuracy.