Final answer:
The rate of petroleum degradation after the Exxon Valdez oil spill was likely limited by both low temperatures and insufficient concentrations of inorganic nutrients, which are crucial factors for the metabolic processes of hydrocarbon-degrading bacteria.
Step-by-step explanation:
The Exxon Valdez oil spill off the coast of Alaska faced challenges in petroleum degradation due to environmental factors that limit the effectiveness of hydrocarbon-degrading bacteria. Among these limiting factors, two stand out as being particularly significant:
- Temperature: The cold Alaskan waters slow down the metabolic rates of bacteria, impeding their ability to degrade hydrocarbons efficiently.
- Inorganic nutrient concentrations: Adequate levels of nutrients like nitrogen and phosphorus are essential for bacterial growth and activity. A deficiency in these nutrients can greatly reduce the bacteria's capacity for degrading petroleum.
Thus, the correct answer is D) temperature and inorganic nutrient concentrations. These combined factors most likely limited the rate at which hydrocarbon-degrading bacteria could solubilize and degrade the oil following the spill. It's important to note that bioremediation efforts, such as the addition of inorganic nutrients, can help promote bacterial growth and enhance the degradation process.