Algae and Diatoms

Out of the thousands of types of algae, one group, the diatoms, constitute the class Diatomaceae or Bacillariophyceae, which absorb soluble silica from water even at 

Seawater contains only 2-14 ppm of SiOj and is far below saturation with respect to amorphous silica (34). Part of this is suspended fragments of siliceous organisms (35). Siever has pointed out that the major mechanism for the predpitation of silica on the surface of the earth is biochemical (36). The various organisms responsible for silica deposition were reviewed by Voronkov, Zelchan, and Lukevits (4a). The microcrystalline quartz minerals jasper and chalcedony are probably transformation products of very early diatomite deposits. About two-thirds of the deposited silica is from diatoms and the remainder from radiolaria and sponges. 

A monograph by Lewin and Lewin (43a) summarized what was known of the subject in 1962, and Voronkov, 2 1chan, and Lukevits (4a) listed references up to 1975. A monograph on the biochemistry and physiology of diatoms (43b) appeared in 1977. 

Flgurj 12. Electron micrograph of the silica skeleton of a diatom. [Her (l). by permission Cornell University Press.] 

The question is whether in the living cell the open spaces In the silica.are occupied by living tissues or only an aqueous phase. The mechanism by which silica is deposited in predetermined form is unknown. Observation of the early stages of frus-tule formation in a diatom have been described by Dawson (46c). 

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Pohnert G, Boland W (2002) The oxylipin chemistry of attraction and defense in brown algae and diatoms. Nat Prod Rep 19 108-122... 

Pickett-Heaps JD, West JA, Wilson SM, McBride DL (2001) Time-lapse videomicroscopy of cell (spore) movement in red algae. Eur J Phycol 36 9-22 Pohnert G, Boland W (2002) The oxylipin chemistry of attraction and defense in brown algae and diatoms. Nat Prod Rep 19 108-122... 

In spite of his devotion to organic and inorganic chemistry, Cleve never lost interest in biology. During bis later years he made an extended study of the plankton of Skagerak and the North Sea, especially of the freshwater algae and diatoms, in order to locate the ocean currents. 

Markham, J. W., and Hagmeier, E. (1982). Observations on the effects of germanium dioxide on the growth of macro-algae and diatoms. Phycologia. 21, 125-130. 

Feeding regime Various combinations of trout chow, yeast, alfalfa, green algae, and diatoms given in excess Do not feed... 

Bacteria, algae, and diatoms that accumulate on the coarse sand layer of the filter bed metabolize nutrients, etc., from the supply, thereby removing them. Among the benefits of slow filtration is removal of up to 50% of any chlorinated pesticide content of the influent water [6]. Slow filtration may require a prior aeration step to ensure that the biochemical processes remain aerobic, since anaerobic operation can form sulfides and amines from sulfate and nitrate, which would contribute bad odors or tastes to the supply. 

That portion of the plankton community comprised of tiny plants (e.g., algae and diatoms), planetary albedo... 

ASP s systematic approach to applied biology started with collecting algae from sites in the west, northwest, and southeastern regions of the continental US and Hawaii. Researchers collected over 3000 strains. After screening, isolation and characterization efforts, the collection contained around 300 species, mostly green algae and diatoms. 

Screening of the antitumor activity of extracts of the intestine of Strongylocentrotus intermedius of Japanese origin (Hokkaido) led to the isolation of 3 -sulfoquinovosyl-l -monoacylglycerides whose origin is probably algae and diatoms from the diet (Sahara et al., 1997). The fatty chains consist mainly of myristic (2-32%), palmitic (57-86%) and... 

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