Research Areas > Nutrients > Comparison of Nutrient Inputs, Water Column Concentrations, and Macroalgal Biomass in Upper Newport Bay

Project: Comparison of Nutrient Inputs, Water Column Concentrations, and Macroalgal Biomass in Upper Newport Bay

Background and Objective

Newport Bay provides a variety of natural habitats for terrestrial and aquatic species, supports fisheries and offers recreational opportunities. San Diego Creek is the primary freshwater input to the Bay, and was identified by the Santa Ana Regional Water Quality Control Board (RWQCB) as having excessive nutrient inputs through the Clean Water Act 303(d) listing process. High nutrient loads are suspected of causing excessive growth of macroalgae in the Bay.

A literature search focusing on synoptic nutrient water quality and macroalgal biomass data in estuaries was conducted to determine whether water quality objectives for total inorganic nitrogen (TIN) in San Diego Creek were similar to concentrations that induced macroalgal blooms in other estuaries. The literature review included data from estuaries around the world, data from estuaries in southern California, and mass emission and receiving water data measured in UNB.

Status

This study took place in 2000.

Methods

A literature review was conducted to compare estuaries from around the world and southern California to data from Upper Newport Bay. Fourteen studies met the criteria to be included in the SCCWRP study.

Findings

A wide range of values for nutrient concentrations were observed. Newport Bay exhibited water column nutrient concentrations in the lower ranges of values available for other estuaries, but had comparatively high values for nutrient loading levels. Data were insufficient to assess whether the TMDL for TIN was appropriate. This was due to:

Partners

This project was partially funded by the Santa Ana Regional Water Quality Control Board.