The number of algal blooms has increased off California’s coast in the past 10 years and it may be due to the introduction of nutrient-rich urban wastewater.
To see if a link exists, scientists in the state are taking advantage of month-long maintenance work on pipelines within the Orange County Sanitation District that will open a temporary discharge site one mile from shore.
The researchers intend to find blooms that occur using stationary monitoring equipment and then gather more data with submarine gliders, sensor moorings and research vessels provided through funding from the National Oceanic and Atmospheric Administration.
Urban wastewater from Orange County, though treated and cleaned extensively, has been found to be more rich in nutrients than the water into which it flows. Those nutrients include phosphorus and nitrogen, which support the growth of algae and aquatic plants. Overgrowth from the excess nutrients is too much for ecosystems to handle and decay of algae after the flow of nutrients ceases can rapidly deoxygenate surrounding water and threaten aquatic life.
Data from the study will give greater insight into the impacts that treated wastewater has on the environment, public health and algae growth.
The team is led by University of Southern California in partnership with the Southern California Coastal Ocean Observing System and the Orange County Sanitation District. Daily progress updates can be found here.
Image: A diagram of the repairs that led to the research (Credit: Orange County Sanitation District)