Look there is no doubt that Humans are helping cause the nutrient depletion in the ocean, but it is NOT because of sewage processing, at least not entirely. the Main reason is absolutely because of over harvesting the ocean. Algae grows, feeds marine life, and we take it out. The fish don't end up eating each other or dyeing in the ocean, it is not recycled in the normal way. So we end up eating the fish, and yes we prevent a lot of the nutrients from returning from the ocean because of water cleaning. However, it is not the filtration, but rather the fishing that is the real problem. We clean the water, not because we are worried about nutrients, but rather because of all the other shit in our water (latex chemicals, antibiotics, etc etc. all the shit people poor down the drain on a daily basis. and I assure you that those things entering the ocean will do lots of harm. I am sure hefty amount of mercury will be a nice addition to the ocean.
To my knowledge, we have not come up with a good way distributing nutrients back to the ocean without causing massive, deadly algae blooms. But let us be clear, we are destroying the ocean, possibly changing the climate (although I don't see how the increased metabolic activity could effect hurricane patterns in such a severe way), because we are Greedy, obese, psychotic capitalists, who only think of one thing, the bottom line. It is not because we are trying to keep our children from getting brain damage, by cleaning our waters.
If you honestly believe the blame is on the people trying to clean up the shithole of a mess, rather than the reckless profiteering at the expense of the planet, than you are truly lost. Sure climate science is still very new and inaccurate, but it gets closer to the truth every day, but I can sure as hell say, they have a better idea of what is going on than your little correlations.
