ANSWER:
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.
