Lycopodium clavatum tablets are commonly added as a spike to determine dinoflagellate cyst concentrations in sediments. In this study we investigate the effects of different processing techniques on dinoflagellate cyst concentrations using well-mixed sediment samples from Saanich Inlet, British Columbia, Canada. At the onset of any dinoflagellate cyst investigation, we suggest following the recommendations of Maher (1981) to experimentally adjust the sample size to obtain a ratio close to ~2 of dinoflagellate cysts counted to Lycopodium spores counted, in order to obtain reproducible concentrations. Results further show that both oven-drying at ~45 °C and freeze-drying are viable, non-destructive techniques yielding reproducible results. Use of warm HCl (40-60 °C) for a short time (30. min) is harmless, whereas treatment with warm HF (40-60 °C) affects the reproducibility of the concentrations. Pre-sieving can result in loss of cysts and/or spike but this can be easily monitored by checking the residue. Perforated metal sieves show more consistent results than the Nitex nylon meshes. The use of 30. second sonication does not affect the reproducibility, and is advised to remove amorphous organic matter. Adding the Lycopodium spike at the end of preparation yields consistently lower concentrations, which were usually not reproducible, suggesting noticeable losses of Lycopodium spores during processing if the Lycopodium spores are added at the beginning. This method can be considered a viable alternative, but the discrepancy should be taken into account.
Bibliographical noteFunding Information:
We are grateful to Captain Brown, crew of the MSV Strickland, Ms. Sarah Thornton and EOS313-2009 students for the help with sediment sample collection. Ms. Alanna Krepakevitch is thanked for her help during subsampling and freeze-drying. Dr. Kenneth Mertens is a postdoctoral fellow of FWO Belgium. This research was partly conducted by Dr. Kenneth Mertens while working as a postdoctoral researcher at University of Victoria, Canada. This research was partly supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) through a grant to Dr. V. Pospelova. The editor and two anonymous reviewers are thanked for comments that improved the manuscript.
Copyright 2012 Elsevier B.V., All rights reserved.
- Absolute abundance
- Dinoflagellate cyst
- Lycopodium clavatum tablets