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On the Culture of the Plankton Diatom Thalassiosira grauida Cleve, in Artificial Sea-water

Published online by Cambridge University Press:  11 May 2009

E. J. Allen
E. J. Allen
Affiliation:
Director of the Plymouth Laboratory.
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Extract

1. Attempts to obtain good cultures of Thalassiosira gravida in a purely artificial medium, made by dissolving in doubly distilled water Kahlbaum's pure chemicals in the proportions in which the salts occur in sea-water, adding nitrates, phosphates and iron according to Miquel's method and sterilizing the medium, have not succeeded.

If, however, a small percentage of natural sea-water (less than 1 per cent will produce a result) be added to the artificial medium and the whole sterilized excellent cultures are obtained, which are often better than any which have been got when natural sea-water forms the foundation of the culture medium.

The result appears to be due to some specific substance present in minute quantity in the natural sea-water which is essential to the vigorous growth of the diatoms. The nature of this substance it has not been possible to determine, but some evidence seems to suggest that it is a somewhat stable organic compound.

Provided the 1 per cent of natural sea-water is added, the various constituents of the artificial sea-water forming the basis of the culture medium can be varied in amount within wide limits. The salinity of the medium can also be considerably altered without serious detriment to the cultures.

The experiments recorded are of interest as furnishing another instance of the importance in food substances of minute traces of particular chemical compounds. They may also eventually throw light upon the nature of the conditions in the sea which are specially favourable to the production of plant life and therefore also of the animal life which that plant life sustains.

Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 10 , Issue 3 , October 1914 , pp. 417 - 439
Copyright
Copyright © Marine Biological Association of the United Kingdom 1914

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References

* Allen, E. J. and Nelson, E. W. “On the Artificial Culture of Marine Plankton Organisms,” Journ. Mar. Biol. Assoc., VIII, 1910.Google Scholar Also in Quart. Journ. Micr. Sci., Vol. LV, 1910. The two papers are identical.

† Q.J.M.S., Vol. LV, p. 393.

* Allen and Nelson, loc. cit., p. 460. [Q.J.M.S., p. 412.] The species was then thought to be a variety of Thalassiosira decipiens. Subsequent examination by Mr. Nelson has convinced him that it is really Th. gravida. The extreme delicacy of the siliceous skeleton of these diatoms makes the determination of species founded chiefly on valve structure very difficult. The species was formerly thought to be a variety of Thalassiosira decipiens Grun. since the only markings that were observed were characteristic of this species, although no markings at all could be resolved with the great majority of valves. Examination of the present cultures by Mr. Nelson with more perfect apparatus has shown the typical Th. gravida Cleve valve structure to which species this form is now referred. It is not unlikely that the older cultures were a mixture of Th. decipiens and gravida from which the decipiens have died out.

† It should be remembered that possibly the presence of some bacteria in the cultures is necessary for their success, thoughMiquel, (Le Diatomiste, I, 1893, pp. 153–6Google Scholar) states definitely that he obtained cultures of fresh water diatoms which were entirely free from bacteria, and Richter, (Ber. deut. bot. Gesell, XXI, 1903Google Scholar and later papers) also succeeded in obtaining such bacteria-free cultures on solid culture media.

* The size of each plate was 120X44X6 mm.

† See Allen and Nelson, loc. cit., p. 432 [Q.J.M.S., p. 375].

* In connection with the preparation of the artificial sea-water I received constant help and advice from my colleague, Mr. D. J. Matthews. Without his ready assistance in connection with all chemical questions this investigation could hardly have been carried out.

† “Challenger” Report, Chemistry, Vol. I, p. 203.

* 2.6 c.c. was the amount generally used, as the increased alkalinity is favourable to diatom growth. See below.

* Cf. Allen and Nelson, loc. cit., p. 452 [Q.J.M.S., p. 401]. The figure here given was derived from later experiments.

† Allen and Nelson, loc. cit., p. 428 [Q.J.M.S., p. 370]. For details as to the preparation of Solution B that paper or Miquel's original account should be studied.

‡ Filter papers should not be used to filter off the precipitate. They appear to contain some substance which inhibits the growth of the cultures. The cultures were made in wide-mouthed spherical glass flasks covered with glass capsules. Cotton wool plugs were not used, as these were found to be injurious to the growth of the diatoms.

* Allen and Nelson, loc. cit., p. 447 [Q.J.M.S., p. 394].

* Richter, O., Verh. d. Gesell. deut. Naturf. u. Ärzte., Breslau, II, 1904,Google Scholar and Akad., S.B.K.Wiss. Wien., CXV, 1906.Google Scholar

* Le Diatomiste, I, 1890–3, p. 95.

* In consequence of the work ofThornton, and Smith, Geoffrey on Euglena (Proceed. Roy. Soc., B., Vol. LXXXVIII, p. 151, 1914CrossRefGoogle Scholar) special attention was given to tyrosine, and a arge number of different concentrations were tried. Entirely negative results were, however, obtained.

† The use of these three substances alone and with atropine was suggested by the work of H. C. Ross on “Auxetics.” See Ross, H. C., Induced Cell-Reproduction and Cancer, London, J. Murray, 1910;Google ScholarFurther Researches into-Induced Cell-Reproduction and Cancer, I and II, London, J. Murray, 1911 and 1912.

* Cf. Allen and Nelson, loc. cit., p. 430, et. seq. [Q.J.M.S., p. 373].

* Allen and Nelson, loc. cit., p. 453 [Q.J.M.S., p. 402].

* A summary of this work, as described at the meeting of the British Association in Dundee (1912), will be found in Science Progress, January, 1913, pp. 423–5.

† The Lancet, Nov. 4th, 1911, p. 1266.

‡ Journal of Physiology, Vol. XLIV, 1912, p. 425.

§ Proceed. Roy. Soc., B., Vol. LXXXVIII, p. 151, 1914.