And while algae like nitrogen in general, they love ammonium. When ammonia hits in the water, it is ready to use. Algae don't have to spend any energy to convert it, so more of the nutrient is used for growth. Simply put, a pound of ammonium will spur more algae growth than a pound of nitrate. So, unlike other nitrogen deposition, ammonia raises special concerns about where it comes down - especially if it is on salt water.
Excess algae fueled by too many nutrients is the largest water quality problem in the Bay.
When there is more algae than predators can consume, the tiny, one-cell plants ultimately die, sink to the bottom and decompose in a process that depletes the water of oxygen needed by fish and other creatures. Algae blooms also cloud the water, blocking light from reaching important underwater grasses that provide food and habitat for waterfowl, crabs, juvenile fish and a variety of other aquatic life. Changing the type of nitrogen entering the water from nitrate to ammonia may also cause a fundamental change in the algae community - the building block for the aquatic food web. Species that best accumulate ammonia may be different from those that have thrived on nitrate for centuries. Paerl is also concerned that the air is providing a new route to the water.