How do changes in nutrient levels affect the structure of aquatic food webs?

The effects of increasing or decreasing the nutrient levels in an aquatic food webs is described in the explanation.

Explanation:

If the nutrient levels in an aquatic food web increase moderately then it will result in increased production of the primary producers and the consumers.

But if the nutrient levels are increased excessively, like in eutrophication, then the increased level of nutrients will result in overproduction of the consumers like fishes, etc. Hence, there will be a scarcity of resources like oxygen in the water to support them and this will lead to a decline in biodiversity of the aquatic food web.

If the nutrient levels are decreased, then there will be competition for resources among the species which will ultimately lead to the decline of some species from the aquatic food web.

"d.) carbon dioxide and hydrogen sulfide"

answer: decrease

a limiting factor is the one which decrease the abundance, distribution and causes extinction of the population of species in a ecosystem. here, predators including hawks, owls and snakes are the limiting factor for the population of mexican free tailed bat.   although bats are nocturnal animals as they forge for food at night these predators also may remain active during night which can decrease the population of the mexican free-tailed bats. also, these bats eat only one type of insects that are moths. the food can also be a limiting factor as all 400 members are dependent upon same type of food needs that are moths. the decrease in the moth population can cause decrease in population size of the mexican free-tailed bats.

therefore, the scenarios will most likely to decrease the population size of the mexican free-tailed bats.