Anabaena on South Fork at Phillipsville. Oxygen bubbles trapped in colonies that cause segments to float and drift. (Eel River Recovery Project)
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In an effort to collect more information and build a deeper understanding of cyanotoxins in the Eel River, grassroots volunteers have joined together to create the Eel River Recovery Project (ERRP) and are building data for the community about the river health for the general public.

With low water levels during the summer months, noxious blooms are stimulated in the warm, stagnant state, encouraging the development of algal toxins which can be fatal if the water is ingested.

“When dog deaths first occurred, there was insufficient information available to the public and; therefore, significant risk to people and pets,” Eel River Recovery Project Managing Director Patrick Higgins said.

The result was a concerted effort with the University of California, Berkeley, the Humboldt County Department of Public Health, North Coast Regional Water Quality Control Board and ERRP.

Once a beneficial algae, Cladophora, meets the abundant sun, a photosynthetic process is stimulated and creates green spires with oxygen bubbles, causing segments to become buoyant and create scum and floating mats on the water surface. This results in patches of Anabaena which can be lethal for dogs if they romp through the patches and later lick their fur. This algae is also toxic for human consumption and raises concerns about recreation and water usage overall.

“The South Fork Eel River had the highest levels of anatoxin-a in most years. In 2013, the highest levels were in the lower reach at Phillipsville; in 2014, the highest levels were measured farther upstream, near Piercy. The pattern changed in 2015, when the highest anatoxin-a levels were measured in the lower Middle Fork, upper Eel, the lower Eel River, and the Van Duzen River near Carlotta, as well as in the South Fork,” the ERRP report indicates.

Map of locations of cyanotoxin samplers (SPATTs) placed in the Eel River basin from 2013-2017. (Eel River Recovery Project)

Water temperatures in addition to low flows are thought to be the major contributors in regards to the high levels of cyanotoxins. However, the ERRP is also looking at nutrient pollution as a contributing factor.

Another issue is evapotranspiration. With the varied landscape since the age of logging, there is an increase in dense forests which likely play a major role.

“Logging of old-growth coniferous forests has also changed wildland hydrology in that the dense forest of smaller trees that replaced the late seral stands use much more water,” Higgins said.

“ERRP has expanded into niches all over the Eel River watershed and seems to be able to grow to meet the needs of the community.  Our amazing ability to generate volunteer participation and other accomplishments is leading to an increase in credibility that is leading to greater grant funding opportunities and a willingness of the public and businesses to contribute to ERRP.  People who values services such as cyanotoxin monitoring should consider becoming members.”

The public can reach the ERRP at 707-223-7200 or eelrecovery@gmail.com.

Lauren Tyler can be reached at 707-441-0503.

 

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