The first collecting trips made by SERI researchers took place in the fall of 1983. Five saline hot springs in western Colorado were selected for sampling because of their abundant diatom populations, and because a variety of water types was represented. Water samples were used to inoculate natural collection site water that had been enriched with N (ammonium and nitrate) and phosphate (P) and then filter sterilized. Water samples were also taken for subsequent chemical analyses. The temperature and conductivity of the site water were determined at the time of collection. Conductivity ranged from 1.9 mmhos^cm-2 at South Canyon Spring to 85.0 mmhos^cm-2 (nearly three times the conductivity of seawater) at Piceance Spring. Water temperature at the time of collection ranged from 11° to 46°C.

In the laboratory, researchers tried to isolate the dominant diatoms from the enriched water samples. Cyanobacteria and other contaminants were removed primarily with agar plating. Approximately 125 unialgal diatom strains were isolated. The predominant genera found were Achnanthes, Amphora, Caloneis, Camphylodiscus, Cymbella, Entomoneis, Gyrosigma, Melosira, Navicula, Nitzschia, Pleurosigma, and Surirella.

A standardized lipid analysis protocol was not yet in place to screen these strains. However, many algal strains were known to accumulate lipids under conditions of nutrient stress. Microscopic analysis of cells grown under N-deficient conditions revealed lipid droplets in several of the strains, particularly in Amphora and Cymbella.

In addition to yielding several promising algal strains, this initial collection trip was useful for identifying areas for improving the collection and screening protocols. Some of these improvements were implemented for the 1984-collecting season, and are described in the next section.

I Publications:

Barclay, W. R. (1984) “Microalgal technology and research at SERI: Species collection and characterization.” Aquatic Species Program Review: Proceedings of the April 1984 Principal Investigators ’Meeting, Solar Energy Research Institute, Golden, Colorado, SERI/CP-231-2341; pp. 152-159.