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USGS scientists have gained a better understanding of the nutrient supply and how nutrients affect habitat quality, algal productivity, and food-web dynamics in the Bay-Delta.

The understanding of nutrient supply has come from real-time data collected by sensors co-located with USGS monitoring stations and other sensors deployed by boat. Nutrients, such as nitrogen and phosphorus, provide nourishment essential for growth of aquatic plants, which are the foundation of the food web. Nitrogen and phosphorus are the main components of agricultural and residential fertilizers, and these nutrients can get into the waters of the Bay-Delta. An input of excess nutrients, called “eutrophication,” can cause the growth of invasive nuisance plants, as well as blooms of microscopic algae. Microalgae can thrive and quickly proliferate in response to eutrophication, sunlight, and warm temperatures, leading to harmful algal blooms (HAB). Algal blooms can make water cloudy and discolored, such as in “red tides,” and in some cases the algae produce toxins that can kill fish, mammals, and birds and also harm humans who, for example, could eat contaminated seafood. Even nontoxic blooms can cause problems, because decomposing algae can rapidly deplete oxygen from water, harming aquatic organisms. HABs can severely affect water quality, causing problems for drinking-water treatment operations. Because of continuing eutrophication and projected increased temperatures due to climate change, HABs are a growing threat to the Bay-Delta ecosystem.


For more information see:

Phytoplankton Production and Nutrient Transformations in Shallow Water Wetland Habitats

Nitrogen Dynamics Along the Sacramento River and Links to Phytoplankton Dynamics

High Speed Mapping of Nutrient Distributions and Water Quality Survey—Lower South San Francisco Bay


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