If you need an accessible version of this item please contact JSTOR User Support

Phytoplankton in the English Lakes: II. The Composition of the Phytoplankton in Relation to Dissolved Substances

W. H. Pearsall
Journal of Ecology
Vol. 20, No. 2 (Aug., 1932), pp. 241-262
DOI: 10.2307/2256077
Stable URL: http://www.jstor.org/stable/2256077
Page Count: 22
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
Phytoplankton in the English Lakes: II. The Composition of the Phytoplankton in Relation to Dissolved Substances
Preview not available

Abstract

By analysing the periodicity of the more important plankton algae in comparison with the results of water analyses, it appears that: (1) Diatoms occur when the waters are richest in nitrate, phosphate and silica (in winter and spring). The appearance of Asterionella is correlated with higher concentrations of phosphate, nitrate and calcium than that of Tabellaria fenestrata. Melosira granulata shows a very definite correlation with waters rich in organic matter and in Myxophyceae, and forms maxima in water of low calcuium content. (2) The green algae and desmids occur in summer when nitrates and phosphates are low. Two groups of green colonial forms are distinguished, occurring before and after the desmid phase. Desmids occur particularly when calcium and the nitrate/phosphate ratio is low. No evident effect of peaty water is detected. (3) Dinobryon appears to be favoured by somewhat higher ratios of nitrate to phosphate. It may replace diatoms when the silica or calcium content gets low in spring. (4) Myxophyceae show a general correlation with high organic matter, and have the ability to grow rapidly in minimal quantities of nitrate and phosphate. Oscillatoria tenuis has apparently a higher calcium requirement than Coelosphaerium Kutzingianum.

Page Thumbnails

  • Thumbnail: Page 
[241]
    [241]
  • Thumbnail: Page 
242
    242
  • Thumbnail: Page 
243
    243
  • Thumbnail: Page 
244
    244
  • Thumbnail: Page 
245
    245
  • Thumbnail: Page 
246
    246
  • Thumbnail: Page 
247
    247
  • Thumbnail: Page 
248
    248
  • Thumbnail: Page 
249
    249
  • Thumbnail: Page 
250
    250
  • Thumbnail: Page 
251
    251
  • Thumbnail: Page 
252
    252
  • Thumbnail: Page 
253
    253
  • Thumbnail: Page 
254
    254
  • Thumbnail: Page 
255
    255
  • Thumbnail: Page 
256
    256
  • Thumbnail: Page 
257
    257
  • Thumbnail: Page 
258
    258
  • Thumbnail: Page 
259
    259
  • Thumbnail: Page 
260
    260
  • Thumbnail: Page 
261
    261
  • Thumbnail: Page 
262
    262