Changes in the stream algal flora were observed during a multi—disciplinary logging study of small watersheds in Oregon. Clearcut logging was applied to one watershed of 71 hectares, while a second watershed of 304 ha was patch—out leaving a buffer—strip of vegetation along the stream channel. A third watershed of 203 ha was not logged but remained as a control. Pre—logging and post—logging oxygen levels, temperature, and sedimentation loads were analyzed. Access roads were built in 1963, and logging completed in 1966. Analysis of the algal communities of the three watershed streams prior to the logging operation of 1966 indicated that the communities were predominantly a periphyton type composed mainly of diatoms. Immediately following the yarding operation of the clearcut watershed, large quantities of Sphaerotilus natans colonized all debris and mud in the stream, and a change in the algal floral appeared to take place. Large mats of green algae were observed colonizing all mud and slash. Results from glass substrates indicate that some changes may have taken place in the diatom community.

This paper describes a method of direct measurement of the primary production of the benthic algal community in the lotic environment that eliminates calculations of diffusion and is adaptable to the various chemical analyses used to indicate rates of production.

A newly formed reservoir in the southwestern part of the United States was analyzed for man's impact on the eutrophication of the impoundment. The analysis of the 14C net productivity (mg '2C/m2 per day) indicated that the area studied was naturally eutrophic. Significant differences in net production were observed among the sites, as the area where man's recreational activities are highly concentrated had a significantly higher production rate than the other sites investigated.Mean monthly estimate of production for all the sites, and monthly and yearly estimates for the area studied are also included.

Sampling sites, types of constituents analyzed, and schedule of sampling during 1988 for water and bottom sediment .... 25 11. Sampling sites, types of constituents analyzed, number of samples collected, and schedule of sampling during 1988