The impact of ultraviolet-B radiation on the motility of the freshwater epipelic diatom Nitzschia lineariz

  1. Adrienne L. Moroz1,
  2. James M. Ehrman2,
  3. Thomas A. Clair2,
  4. Robert J. Gordon3,
  5. Irena Kaczmarska1

Article first published online: 24 DEC 2001

DOI: 10.1046/j.1365-2486.1999.00225.x

Issue

Global Change Biology

Global Change Biology

Volume 5, Issue 2, pages 191–199, March 1999

Additional Information

How to Cite

Moroz, A. L., Ehrman, J. M., Clair, T. A., Gordon, R. J. and Kaczmarska, I. (1999), The impact of ultraviolet-B radiation on the motility of the freshwater epipelic diatom Nitzschia lineariz. Global Change Biology, 5: 191–199. doi: 10.1046/j.1365-2486.1999.00225.x

Author Information

  1. 1

    Department of Biology, Mount Allison University, Sackville, NB, E0A 3C0, Canada,

  2. 2

    Environment Canada – Atlantic Region, PO Box 6227, Sackville, NB, E4L 1G3, Canada,

  3. 3

    Nova Scotia Department of Agriculture and Marketing, PO Box 550, Truro, Nova Scotia, B2N 5E3, Canada

* Dr Thomas A. Clair, fax +1/ 506 364 5062, e-mail tom.clair@ec.gc.ca

Publication History

  1. Issue published online: 24 DEC 2001
  2. Article first published online: 24 DEC 2001
  3. Received 3 November 1997;revised versionreceived 2 April andaccepted 16 April 1998

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Keywords:

  • epipelic diatoms;
  • motility;
  • UV-B

Abstract

Depletion of the stratospheric ozone layer has been of increased concern due to correlated increases in ambient ultraviolet radiation. Our research investigated the diel response of the motile behaviour of Nitzschia lineariz in both natural (freshwater stream) and experimental conditions. We classified the behaviour of individual diatom cells as gliding, immobile and oscillating. The experimental conditions were of simultaneous exposure either to net ambient solar radiation (control) or to ambient plus enhanced UV-B levels (treatment). UV-B for the control condition was filtered out using polyester filters; cells exposed to UV-B were irradiated through cellulose diacetate filters. UVB-313 levels were augmented to 33% (290 mW m–2) and 66% (365 mW m–2) above the local average ambient levels (220 mW m–2) for 10 h. The mobile behaviour of cells was examined and quantified every 2 consecutive hours from dawn to dusk in subsampled populations. The number of gliding cells in subsample populations declined on overcast days at both the 33 and 66% UV-B enhancement levels, whereas the number of immobile and oscillating cells increased with increased UV-B exposure. On sunny days, mobile behaviour was not affected at either enhancement level, which suggests that cellular repair mechanisms may be activated during sunny conditions.

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