Observations on Soil Algae

Qualitative and quantitative observations on green and yellow-green algae in some English soils

“…In early studies of British soils (Bristol, 1920;Bristol-Roach, 1927;James, 1935;Fritsch & John, •942;Lund, 1947a) much of the diversity of these algae was overlooked. In particular many of the green spherical chlorococcacean algae were named as Chloroeoccum humicolum (Naeg.)…”

“…Little work has been performed on these groups of soil algae in this country and that which has been done has been mainly of a floristic nature (Bristol, 1920;Bristol-Roach, 1927;James, 1935;Fritsch & John, 1942;Lund, 1947a, b) although Lund (1947a) also presented comparative data on the number of algae in several soils without attempting to make absolute assessments.…”

The Effect of Some External Factors on Nitrogenase Activity in the Free‐Living and Endophytic Nostoc of the Liverwort Blasia pusilla

“…The nitrogen-fixing capacity of the free-living algal isolate is greatest at pH levels above 6.5 and is greatly depressed at pH levels below this, in common with most heterocystous blue-green algae which rarely grow or fix nitrogen at pH levels below 6 (Lund 1947, Jurgensen and Davey 1968, Dooley and Houghton 1973. However, the in situ endophytic colonies are capable of relatively high fixation rates over a wide pH range.…”

Effects of Abiotic Factors on Acetylene Reduction by Cyanobacteria Epiphytic on Moss at a Subantarctic Island

“…Even during these dry periods, the bryophyte layer in the mires remains wet due to its high water-holding capacity and upward capillary movement of water from the waterlogged peat substratum. At many subpolar and cold temperate sites moisture is an important factor determining the distribution of cyanobacteria (14,28,32,33), and N fixation activity in free-living and lichenized forms depends on thallus moisture content, often up to high saturation values (3, 4, 11, 36). AR by moss-Nostoc associations at the Vestfold Hills in Antarctica was appreciably inhibited by partial desiccation over a range of temperatures (-3.5 to 25°C) (12).…”