Smear and spray preparation techniques put to the test (II): reproducibility and accuracy of calcareous nannofossil assemblage counts
2007 (English)In: Journal of Nannoplankton Research, ISSN 1210-8049, Vol. 2, 92-100 p.Article in journal (Refereed) Published
In an earlier study (Henderiks and Törner, 2006, Marine Micropaleontology 58, 207-218), nannofossil proportion estimates between replicate smear slides showed substantially higher variance than those obtained from replicate sprayed slides. This study revisits this potentially disconcerting issue, detailing the internal accuracy and reproducibility of relative nannofossil species abundances obtained with the same two preparation techniques: the simple smear slide and the spray method. In addition, accuracy and reproducibility were tested for a semi-quantitative method, in which the number of specimens per mm2 is determined from smear slides.
To test the overall reproducibility of these two preparation methods, replicate slides were prepared and analyzed with each technique for a set of six samples selected from Oligocene deep-sea sediments from the Equatorial Pacific (ODP Leg 199). Both smear and spray replicates indicate a good reproducibility of proportion estimates within the same method, since no statistically significant differences between the replicate slides were observed. However, when comparing the smear with spray replicates, the data set reveals significantly different species proportion between slides, indicating that the two preparation techniques are not statistically comparable. It appears that the dominant taxon, Cyclicargolithus floridanus, is enriched in the smear slides, whereas the abundance of the subordinate taxa is about the same for either method. A comparative test of abundance counts between dense and thin areas on the same smear slide indicates nannofossil size sorting in the smearing technique, with proportionally more large specimens in the dense ripples. This study confirms an earlier observation that the smear method results in lower proportion estimates of larger nannofossil taxa in comparison to the spray method.
Place, publisher, year, edition, pages
UK: Cambridge University Press , 2007. Vol. 2, 92-100 p.
calcareous nannofossils, preparation techniques, light microscopy, accuracy, reproducibility, biostratigraphy
Research subject Marine Geoscience
IdentifiersURN: urn:nbn:se:su:diva-27589OAI: oai:DiVA.org:su-27589DiVA: diva2:216395