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

A Nine-Year Study of the Phytoplankton of the Eutrophic and Non-Stratifying Loch Leven (Kinross, Scotland)

A. E. Bailey-Watts
Journal of Ecology
Vol. 66, No. 3 (Nov., 1978), pp. 741-771
DOI: 10.2307/2259295
Stable URL: http://www.jstor.org/stable/2259295
Page Count: 31
  • 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
A Nine-Year Study of the Phytoplankton of the Eutrophic and Non-Stratifying Loch Leven (Kinross, Scotland)
Preview not available

Abstract

(1) Observations from 1968 to 1976 at mainly weekly intervals on the phytoplankton of the shallow, eutrophic and non-stratifying Loch Leven have revealed marked seasonal and annual differences in species-composition and population densities. However, long term trends were apparent, with decreasing concentrations of chlorophyll a, total dry weight and total volume of phytoplankton, although an increase in the latter two features in 1976 coincided with a massive growth of a pale form of Oscillatoria agardhii Gomont. (2) Trends were apparent also in increasing size of dominant algae and decreasing total numbers of individuals producing the various population maxima. A 3000-fold increase in size has accompanied the change towards large species, e.g. Melosira ambigua (Grun.) Müller, Anabaena flos-aquae Brέb. (ex Born. et Flah.), and Oscillatoria agardhii, which have progressively replaced `nano' forms, e.g. Synechococcus nov. sp., Oscillatoria redekei van Goor and some unicellular centric diatoms. Recent population maxima have rarely exceeded 104 individuals per ml, in sharp contrast to earlier growths commonly of 105-106 individuals per ml. (3) Considerable variation in the percentage chlorophyll a of crop dry weight (0.32-1.96), and the ratios of chlorophyll a to volume (< 1 to > 12 \mu g mm^{-3}) and of dry weight to volume (0.31-1.32 mg mm-3), was associated with the continual changes in species-composition. (4) General features of the algal plankton are discussed in relation to the gross physical and chemical characteristics of the loch, whilst some of the observed trends in plankton quantity and quality are considered in relation to changes in phosphorus loading (a reduction of approximately 1.0 g m-2 P per annum since 1972) and in zooplankton quality (a shift from a Cyclops- to a Daphnia-dominated community since 1971). (5) The need for long-term studies based on close time-interval sampling for information on species and populations is emphasized; one source of misinterpretation of results if species-variation is not taken into account is discussed and illustrated with the use of a simple theoretical model.

Page Thumbnails

  • Thumbnail: Page 
741
    741
  • Thumbnail: Page 
742
    742
  • Thumbnail: Page 
743
    743
  • Thumbnail: Page 
744
    744
  • Thumbnail: Page 
745
    745
  • Thumbnail: Page 
746
    746
  • Thumbnail: Page 
747
    747
  • Thumbnail: Page 
748
    748
  • Thumbnail: Page 
749
    749
  • Thumbnail: Page 
750
    750
  • Thumbnail: Page 
751
    751
  • Thumbnail: Page 
752
    752
  • Thumbnail: Page 
753
    753
  • Thumbnail: Page 
754
    754
  • Thumbnail: Page 
755
    755
  • Thumbnail: Page 
756
    756
  • Thumbnail: Page 
757
    757
  • Thumbnail: Page 
758
    758
  • Thumbnail: Page 
759
    759
  • Thumbnail: Page 
760
    760
  • Thumbnail: Page 
761
    761
  • Thumbnail: Page 
762
    762
  • Thumbnail: Page 
763
    763
  • Thumbnail: Page 
764
    764
  • Thumbnail: Page 
765
    765
  • Thumbnail: Page 
766
    766
  • Thumbnail: Page 
767
    767
  • Thumbnail: Page 
768
    768
  • Thumbnail: Page 
769
    769
  • Thumbnail: Page 
770
    770
  • Thumbnail: Page 
771
    771