Have you ever noticed the bright green algae mats growing along the shorelines in the Ventura River in late Spring? The Surfrider Ventura Blue Water Task Force often receives questions about the presence of these mats. Algae mats are generally produced by nutrient runoff in the water especially after a heavy wet weather winter.
Nutrient pollution contributes excess nitrogen and phosphorus to our watershed which may be sourced to animal manure, pet waste, wastewater, farms, fields, yards, household soaps and detergents. When chemical fertilizers especially are not fully utilized by plants, freshwater algae utilize nitrogen and phosphorus in some cases over-produce and algae growth is present from shoreline to shoreline in the Ventura River.
Algae overproduction is also related to climate change which keeps nighttime temperatures higher than past norms and disrupts the nighttime respiration rates of algae. Benthic algae, which grow from the bottom of the Ventura Riverbed may produce harmful algae blooms, or cyanobacteria which have the ability to produce toxins that are harmful in drinking water, human health, wildlife and dogs.
Our Ventura County Blue Water Task Force has been monitoring the presence of algae mats and cyanobacteria for the past two years in the Ventura River in partnership with Ventura Land Trust and the State Water Quality Board.
We presented our survey findings to the LA Regional Water Quality Board as their staff reconsidered the Total Maximum Daily Loads (TMDL) of pollutants that the Ventura River can maintain before becoming more impaired. The current TMDL was approved in 2012 as the Ventura River was determined to be impaired under the Clean Water Act section 303d. The presence of cyanobacteria in the Ventura River may indicate the TMDL needs to take into account the impact on our warming planet and waterways where harmful algae blooms are increasing.
Click here to read the report.
