MEASURING AND MODELLING THE DYNAMIC RESPONSE
OF REMOTE MOUNTAIN LAKE ECOSYSTEMS TO
ENVIRONMENTAL CHANGE
A programme of MOuntain LAke Research
MOLAR
CHRYSOPHYCEAN analysis
SILICEOUS CYSTS, SCALES, PLANKTON SAMPLES
Chr. Kamenik
R. Schmidt
Institute of Limnology, Mondsee
Chrysophycean analysis
Siliceous cysts, scales
1. Sediment cores
1.1. Coring and subsampling
Procedures followed are according to diatom analysis.
1.2. Preparation
1.2.1 Chemical treatment
Procedures followed are according to diatom analysis (Battarbee, 1986).
1.2.2 LM
Procedures followed are according to diatom analysis (Battarbee, 1986), spiking with microspheres (Battarbee & Kneen, 1982).
1.2.3 SEM
Chemically cleaned suspensions as used for diatoms (without microspheres!) are diluted to an appropriate density, evaporated on cover slips, mounted on SEM stubs and sputtered.
Battarbee, R. W. 1986. Diatom analysis. In: Berglund, B. E. (ed.), Handbook of Holocene Paleoecology and Paleohydrology. John Wiley & Sons Ltd., Chichester: 527-570.
1.3.1 Cysts
Facher, E. & R. Schmidt 1996. A siliceous chrysophycean cyst-based pH transfer function for Central European lakes. Journal of Paleolimnology 16: 275-321.
Duff, K. E.; Zeeb B. A. & J. P. Smol 1995. Atlas of Chrysophycean cysts. Developments in Hydrobiology 99. Kluwer Academic Publishers, Dordrecht, 189 pp.
Unknown cyst types are described according to:
Cronberg, G & C. D. Sandgren 1986. A proposal for the development of standardised nomenclature and terminology for chrysophycean statospores. In: Kristiansen, J. & R. A. Andersen (ed.), Chrysophytes: aspects and problems. Cambridge University Press, Cambridge: 317-328.
1.3.2 Scales and bristles
Asmund, B. & J. Kristiansen 1986. The Genus Mallomonas. Opera Botanica 85: 1-128.
Takahashi, E. 1978. Electron Microscopical Studies of the Synuraceae (Chrysophyceae) in Japan, Taxonomy and Ecology. Tokai, University Press, Tokyo: 1-143.
1.4 Counting and quantification
Magnification: LM: 1000x -1250x (oil immersion, high resolution phase contrast objectives)
SEM: 4800x
The absolute number of each cyst type is calculated by the following equations:
1.5 pH reconstruction
As for diatoms, the pH is calculated by using WA regression and calibration (WACALIB). Cyst optima and tolerances are listed in Facher & Schmidt (1996).
2 Sediment trap samples
2.1 Trap type
A simple Bloesch-type (plastic tubes of 60 cm in length and 6 cm in diameter; 6 tubes per trap) is used.
Bloesch, J. & N. M. Burns 1980. A critical review of sedimentation trap technique. Schweiz. Z. Hydrol. 42: 15-55.
2.2 Sampling
Half of the water can be removed carefully. The rest is filled into plastic bottles and fixed with formol.
2.2.1 Sampling intervals
A pilot study on lake Gossenkolle indicated, that because of low accumulation rates in high alpine lakes, sampling intervals during summer less than monthly were insufficient. Sampling starts 2-4 weeks before ice break and ends 2-4 weeks after the beginning of ice cover. Since cyst production under ice is extremely low, traps are not sampled during winter.
2.3 Preparation
Sediment trap samples are centrifuged and washed carefully (Formol fixation). For further preparation see 1.2.
2.4 Identification, counting and quantification
See 1.3 and 1.4.
Application: Facher E. & R. Schmidt 1996. Application of chrysophycean sediment trap data and a cyst-based pH transfer function of annually laminated sediments (Lake Plesne, Czech Republic). Beih. Nova Hedwigia 114: 219-231.
3. Taxonomic harmonisation
As cyst types occur which are not described until now, individual iconographs are recommended. Finally these cyst types must be taxonomically harmonised.