Acid precipitation lowered the pH of the soil in a terrestrial ecosystem that supported a diverse community of plants and animals. The decrease in pH eliminated all nitrogen-fixing bacteria populations in the area.

Which prediction most accurately reflects the impact this will have on the community?

A. The decrease in pH actually increases the availability of soil nutrients, so other nutrients that were less available cause an increase in primary production and an increase in biomass at other trophic levels.

B. Primary producers will suffer from nitrogen deficiency and the entire community will experience a decrease in carrying capacity.

C. Plants can obtain the nitrogen necessary for growth from the atmosphere, but bacterial communities will be negatively impacted.

D. Since phosphorus can replace nitrogen as an essential nutrient, the impact will be minimal.

Answer: B. Primary producers will suffer from nitrogen deficiency and the entire community will experience a decrease in carrying capacity.

Explanation:

Carrying capacity is the ability of the environment to support the growth and abundance of maximum number of members of the species or diversity of species on the basis of the availability of the resources in the environment.

According to the given situation, acid precipitation will lower the pH of the soil. This will likely to eliminate the nitrogen fixing bacteria. The lack of appreciable concentration of nitrogen in the soil will likely to affect the population of primary producers like plants. The reduction in abundance of plants or primary producers will cause the decrease in carrying capacity of the entire community of animals, birds and humans which are dependent on primary producers as a source of food.