This protocol is a combination of The Quadrat and Leaf Count macrofossil analysis technique (QLCMA) developed at the Southampton Palaeoecology Laboratory (Barber et al., 1994) and used by Barber et al. (1998) and Mauquoy and Barber (1999), and the technique used by Bas van Geel, University of Amsterdam (see Speranza et al., 2000; Mauquoy et al., 2002).
Peat sub-samples of 5 cm3 (1 cm x 1 cm x 5 cm) need to be cut from the core (usually a 'Russian' pattern corer with a 7 or 9 cm diameter, 50x15x10 cm metal boxes, or a 100x10x10 cm Wardenaar peat sampler (Wardenaar, 1987)). As an alternative, peat sub-samples can also be taken from a horizontal 1 cm thick slice with a cylindrical sampler of 2.6 cm diameter, which gives a volume of 5.3 cm3. Please note that 'standard' size Russian corers of 5 cm diameter used for the collection of samples for pollen analysis will NOT provide a big enough sample for macrofossil analysis and subsequent 14C dates. Before sub-sampling 5 mm of peat from the core should be trimmed to avoid contamination and only clean instruments used to avoid the introduction of 'modern' carbon and/or contamination with older or younger macro/microfossils, which could potentially cause problems with future 14C dates.
Plant macrofossil samples should be gently boiled with 5% KOH (to dissolve humic and fulvic acids) and disaggregated on a 100 or 125 µm sieve using a 'squeezy' bottle of distilled water to rinse the sub-sample on the sieve. When sieving, the plant remains in the sieve must be kept just under the water surface (to avoid too much damage and disintegration of, for example, Sphagnum stems with leaves still attached. This can be very important for Sphagnum identification, because stem leaves can help in identification to species level).
Macrofossils retained on the sieve are then transferred to a glass beaker/bowl (approximately 20x10 cm) and only enough distilled water should be added to float the remains, which are scanned using a low power (x10-x50) stereo-zoom microscope. If a large beaker/bowl is unavailable or insufficient space is available under the stereo-zoom microscope to accommodate the beaker/bowl, the sample can be poured into a petri-dish a little at a time, gently stirred, inspected, then more of the sample added to another petri-dish, until all of the remains have been scanned for that sample. Plant macrofossils are then estimated as percentages by using a 10x10 square grid graticule inserted into one of the microscope eyepieces and moving the trough of remains randomly to 15 different views and averaging the results (this is where the total Sphagnum volume percentages within the total macrofossil sample are estimated, in addition to the other main peat components, for example ericaceous rootlets or remains of Eriophorum, and/or volume percentages of Aulacomnium palustre and Polytrichum spp (where present)). Sub-samples which contain well preserved epidermal tissues of monocotyledon species need to be mounted onto slides (temporary slides can be made using water) and identified at x400 magnification. If remains of Eriophorum vaginatum are present there is no need to make microscope slides, because with experience, the characteristics of E. vaginatum are already evident under the stereo-zoom microscope A random selection of at least 100 Sphagnum leaves also need to be mounted on slides and identified at x400 magnification, and the results expressed as percentages of the total identifiable Sphagnum estimated in the first part of the macrofossil analysis.
Fruits/seeds and macroscopic charcoal fragments are simply counted as the number (n) found in each sub-sample. If multiple Petri-dishes are used to analyse the samples, heavier fruits/seeds and macroscopic charcoal fragments are more likely to be found in the final sample. Charcoal fragments can be placed into size classes, e.g., charcoal fragments <0.5mm (length), 0.5-1mm, 1-1.5mm, 1.5-2mm and >2mm. Volume percentages of 'above-ground' ericaceous remains are normally very low, for example Andromeda polifolia leaves, Calluna vulgaris leaves, Calluna vulgaris stems, Empetrum nigrum leaves, Erica tetralix leaves, Vaccinium spp. These remains should also be counted separately.
Once macrofossil analysis of each sample is completed it should be stored in a sealed plastic bag or tube and a few drops of 5% HCl added to prevent further decomposition and contamination by bacteria or fungi. Store sub-samples in the dark in a cold room at 3-4°C (where possible). This procedure needs to be completed, because some of the sub-samples will be subsequently 14C dated (please refer to the guidelines in the 14C wiggle-match dating protocol).
The use of a reference collection of type material is highly recommended, owing to the lack of keys. There are however, good plant macrofossil photographs in Grosse-Brauckmann (1972; 1974; 1992), and Katz et al. (1977). Bas van Geel also has an excellent reference collection of raised bog material in Amsterdam, which will certainly be very useful for ACCROTELM scientists.
Leaves of Sphagnum can be identified using 'The Moss Flora of Britain and Ireland', A. J. E. Smith, 1980, Cambridge University Press, Cambridge and 'Vit Mossor I Norden', Mossornas Vänner 1986, Fjärde upplagen 1995, Vasastadens Bokbinderi AB, Göteborg 1995, ISBN 91-971274-2-7 (this one is good for the Scandinavian Sphagnum species).
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bogs: field stratigraphy and macrofossil data from Bolton Fell
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Grosse-Brauckmann, G. 1972. Über pflanzliche Makrofossilien
mitteleuropäischer Torfe. I. Gewebereste krautiger Pflanzen
und ihre Merkmale. Telma 2, 19-55.
Grosse-Brauckmann, G. 1974. Über pflanzliche Makrofossilien
mitteleuropäischer Torfe. II. Weitere Reste (Früchte
und Samen, Moose u. a.) und ihre Bestimmungsmöglichkeiten.
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Katz, N. J., Katz, S. V. and Skobeyeva, E. I. 1977.
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