Effect of Solar Ultraviolet Radiation on a sub-Arctic Planktonic Food Chain: Daphnia and its Food.


Contact
zellmer [ at ] pflanzenphys.uni-halle.de

Abstract

Summary1. Daphnia was collected from five subarctic ponds which differed greatly in their DOC contents and, consequently, their underwater light (UV) climates. Irrespective of which Daphnia species was present the ponds with the lowest DOC concentrations contained Daphnia with the highest concentrations of eicosapentaenoic acid (EPA). In addition, EPA concentrations in these Daphnia generally decreased in concert with seasonally increasing DOC concentrations.2. Daphnia from three of the ponds was also tested for its tolerance to solar ultraviolet radiation (UVR) with respect to survival. D. pulex from the clear water pond showed, by far, the best UV-tolerance, followed by D. longispina from the moderately humic and D. longispina from the very humic pond.3. In addition, we measured sublethal parameters related to UV-damage such as the degree to which the gut of Daphnia appeared green (as a measure of their ability to digest algae), and whether their guts appeared damaged. We developed a simple, non-invasive scoring system to quantify the gut proportion in which digestive processes were presumably active. This method allowed repeated measurement of the same animals over the course of the experiment. We demonstrated, for the first time, that sublethal damage of the gut precedes mortality caused by exposure to UVR.4. In a parallel set of experiments we fed UV-exposed and non-exposed algae to UV-exposed and non-exposed daphnids. UVR pre-treatment of algae enhanced the negative effects of exposure to natural solar UV-irradiation in Daphnia.5. The UV-related effects we observed in Daphnia were generally not species-specific.



Item Type
Article
Authors
Divisions
Programs
Publication Status
Published
Eprint ID
8822
Cite as
Zellmer, I. , Arts, M. T. D. , Abele, D. and Humbeck, K. (2004): Effect of Solar Ultraviolet Radiation on a sub-Arctic Planktonic Food Chain: Daphnia and its Food. , Arctic, Antarctic, and Alpine Research, Vol. 36, No. 3, pp. 369-376 .


Download
[thumbnail of Fulltext]
Preview
PDF (Fulltext)
Zel2003a.pdf

Download (162kB) | Preview
Cite this document as:

Share
Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email

Research Platforms
N/A

Campaigns
N/A


Actions
Edit Item Edit Item