No abstract

Six laboratory streams are being used to study primary production and community respiration in simple communities under different environmental conditions. A photosynthesisrespiration chamber has been developed to perform expcrimcnts relating primary production to different environmental conditions and to verify primary production measurements made directly in the laboratory streams or in natural streams. Gross primary production in the six streams under 6,000 lux of illumination ranged from 2.4 to 4.7 g of oxygen per m2 per day. Community respiration ranged from 1.6 to 4.2 g of oxygen per m2 per day. The P/R ratios usually varied bctwccn 1.0 and 2.0. The relationship between illumination intensity and primary production was approximately linear between zero and 4,000 lux, and maximum photosynthetic rates were obtained at about 21,000 lux.

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.

SUMMARY The fatty acid composition of 10 species of estuarine phytoplankton was determined using gas‐liquid chromatography. Nine of the species were isolated from Yaquina Bay, Oregon. These species were common components of the phytoplankton of the bay. The tenth species, Isochrysis galbana, was obtained from the Culture Collection of Algae at Indiana University. The 10 organisms comprised 3 species of Chlorophyta, 1 species of Cryptophyta, and 6 species of Chrysophyta. Twenty‐eight fatty acids were found in the 10 species. The fatty acids common to all species were 14:0, 16:0, 16:1, 13:0, 18:1, and 18:2. The Chlorophyta were distinguished by a high content of linolenic acid, 18:3. The diatoms were distinguished by very low amounts of C18 acids and high proportion of 20:5. All species contained a high proportion of palmitic acid, 16:0.

The potential production of estuarine interstitial microalgae from two tidal flats differing in sediment texture was determined manometrically. Sediment cores from the Southbeach tidal flat showed a maximum amount of productivity in the lower intertidal zone whereas sediment cores from Sally's Bend showed no production in this zone. The upper cm of sediment from both tidal flats had a higher amount of gross potential production than subsurface core sections. the sandy substratum from Southbeach had an estimated gross annual production of 275-325 g C m yr whereas the silty substratum of Sally's Bend had an estimated value of 0-125 g C m yr. Respiration/Photosynthesis (R/P) ratios indicate that respiration often exceeds photosynthesis on the Sally's Bend tidal flat.