for the first question:
Ocean currents act much like a conveyer belt. they transport warm water and precipitation from the equator toward the poles and cold water from the poles back to the tropics. this, currents regulate global climate, helping to counteract the uneven distribution of solar radiation reaching Earth's surface.
Answer:
1. Moving the facilities such as crops, lawns, golf courses, and sewers etc would be unrealistic to change because many of the owners would not comprise (costs so much already), yet there are solutions. For example, the town can restrict farmers from poluting the rivers with pesticides as well as fining them and the house developments golf courses and land owners in which the money can be used towards the filteration cost. Another idea would to build cheaper wells to soak up water from different river locations or build barriers around settlements from the river. Another idea would to simply grow natural filters such as using the trees and soil they already had.
2. Of course their are limits such as costs, and figuring out the landscapes of where to build wells, add soil and trees (trees take time to grow) and more that would need plan of action from community leaders in which the people would need to speak with the advisors or the management of the buildings nearby. Without clean water people will get sick or die, and building managers need healthy people to live in their houses and work and grow crops so they'll have to make change.
Protons. Neutrons have no charge, so yeah. Protons are the answer.
Large trees and ferns need water to survive. This suggests that the biome was once very different from the desert it is today. #globalwarming lol