Regardless of whether global warming exists, it seems to me that by our blowing millions of tons of carbon dioxide into the atmostphere every day with our car's tail pipes, that increased level of carbon dioxide SHOULD manifest itself in some way.

One would expect that the result of engine exhaust fumes would be more CO2 dissolving in the waters of our oceans, lakes and rivers. Algae are green because they survive by creating their own food energy by photosynthesis. If there's more CO2 in our air and waters, one would expect large algae blooms as algae absorb more CO2 and H2O and sunlight and combine them to produce sugar. The more food there is in the environment for the algae, the more algae we would expect to see.

But, I really haven't heard of large algae blooms being a problem anywhere.

Whenever we hear of large algae blooms, the finger is always pointed at phosphorus enrichment in the water from fertilizer runoff from agricultural land (farms, mostly), never as a result of increase CO2 levels in our air and water. Is there a reason why we're not seeing huge algae blooms in our oceans as a result of the increased level of CO2 in our atmosphere (and presumably rivers, lakes and oceans?