Feb 09, 2024

January 2024 Field Updates: Tracking Bacteria in Our Creeks

Morro Bay is a popular destination for sailing, paddling, kayaking, and swimming. In order for people to safely recreate in the bay, the waters must be clean. Our program monitors pathogens in Morro Bay and the creeks that drain into it to determine if the waters are safe for recreation and other human uses. Creeks can provide recreation opportunities like local swimming holes. Beyond this, the water in the creeks eventually makes its way to the bay, so high levels of contaminants in the creeks can impact bay recreation, shellfish farming, and other bay uses. To track pathogens in our local creeks, the Estuary Program staff and volunteers conduct monthly monitoring. Data is shared with the public, partners, and local agencies.  

What Are Pathogens?

Pathogens like viruses, bacteria, and parasites are small living organisms that can cause disease. Pathogens can make their way into waterways through many pathways including sewage spills, leaks in septic systems or boat waste holding tanks, stormwater runoff, and waste from pets, farm animals, and wildlife.  

The Estuary Program monitors pathogens in the creeks that drain into Morro Bay. During storms, rain runs off the land and into the nearest creek. This process can transport contaminants such as bacteria into the creeks and eventually to the bay.

How We Monitor Creek Bacteria

There are numerous pathogens that can pose a threat to human health. Because testing for each individual pathogen would be costly and impractical, the Estuary Program tests for what are called bacterial indicators. These are the species that tend to be present when fecal contamination from warm-blooded animals is present. To assess pathogens in freshwater creeks, the Estuary Program uses an indicator bacteria called E. coli.

Each month, Estuary Program volunteers collect water samples from throughout the Morro Bay watershed for bacterial monitoring. At each creek monitoring site, samplers use gloved hands to fill a laboratory bottle with creek water. They then store the bottles in a cooler to ensure that they remain cold during transport. 

An Estuary Program volunteer uses sterile technique to collect a sample from a local creek for bacterial analysis.

Back at the laboratory, the volunteers process the water samples using a standardized method developed by IDEXX. Volunteers mix the sample water with a reagent designed to detect the presence of E. coli, seal the samples in specialized trays, and incubate them overnight. The following day, the volunteers return to the lab to read the results. The volunteers read the trays by shining an ultraviolet (UV) light on them. If E. coli is present, the tray glows a vibrant blue color. 

The photo above shows the analysis results. The four blue, fluorescent squares on the sample tray indicate that the creek water sample contained low concentrations of E. coli.

Partnership with Cuesta College

This project is made possible through a partnership with Cuesta College and Biology professors Drs. Laurie McConnico and Silvio Favoreto. Each month, Cuesta students collect and process creek water samples, with all analysis occurring at Cuesta’s Biology Department laboratory. This partnership gives Cuesta students a unique opportunity to learn real-world field and laboratory skills while supporting our program’s efforts to generate this valuable data.

A student from Cuesta College prepares a bacteria sample for analysis.

How the Data Are Used

The Estuary Program shares the bacteria monitoring results with local partners including agencies, nonprofits, and local landowners. The data can help identify potential sources of bacterial contamination so that we can work with partners to address them. The data also allows us to track long-term trends to determine if human health is being protected.  

To view the monitoring data collected by the Estuary Program, visit the California Environmental Data Exchange Network (CEDEN) website at https://ceden.waterboards.ca.gov/ 

Our monitoring efforts help assess the safety of our bay and creek waters.

Help us protect and restore the Morro Bay estuary!