NEWS
Growing precipitation and diminishing acid rain sends more organic carbon into the coastal waters of North America and Europe. This could have mixed environmental effects, tempering old problems while bringing in some new ones.
Dissolved organic carbon makes the water “darker”, which could inhibit the growth of harmful algal blooms. But it could also increase the bacterial processes that lead to anoxic dead zones.
In an Ecochange study an eutrophication inhibition effect of high organic carbon concentrations was found. Increasing organic carbon in water bodies reduced water clarity and the ability of algae to grow and photosynthesize. This means that increasing organic carbon loading is reducing algae concentrations, and potentially reducing harmful algal blooms.
However, while increasing organic carbon loading is reducing eutrophication, it is creating its own problems. Organic carbon serves as a food source to bacteria, increasing respiration. As a result, oxygen consumption will increase more than oxygen production, and anoxic areas may increase in size.
The research has implications relevant for many aquatic systems in the northern temperate zone. Areas that experience higher precipitation or recovery from acidification will likely experience this phenomenon, and the research findings are relevant for both freshwater and coastal zones. Ecochange scientists sence that even fish production will be negatively affected by the system becoming more heavily based on bacteria.
