Atte Korhola, Eeva-Stiina Tuittila, Minna Valiranta, Jukka Laine (University of Helsinki), Bas van Geel (University of Amsterdam), Dan Charman (University of Plymouth), Frank Chambers, John Daniell, John Hunt, Sally Brain, Garry Bosworth, Derek Thomas (University of Gloucestershire), Heikki Seppä, Dmitri Mauquoy (University of Uppsala), Edgar Karofeld (Tallinn Institute), Fraser Mitchell, Maarten Blaauw (Trinity College , Dublin), Hansjoerg Kuester, Mareike Steffens, (University of Hannover), Jukka Alm (University of Joensuu), Annie Wojatschke (from Germany, visiting University of Gloucestershire), Richard Evershed and Richard Pancost (University of Bristol). (photo)
Michel Magny and Hans van der Plicht
(Michel Magny sent a subsequent written comment)
The meeting was introduced by Frank Chambers who reiterated the project outline as given in the original proposal and reminded the meeting of the workpackage contents and of the requirement to produce 'deliverables' from the project. Additionally Frank informed us that Barry Warner and his Newfoundland site were no longer part of the project, but that we could use data from a different site in Newfoundland, and that we would be generating peat humification data on samples taken from a core recovered there by Paul Hughes from the University of Southampton. These samples were already being worked on at the University of Gloucestershire. Frank also remarked that the time-span to be considered in the project overall would be the last 4,500 years.
The rest of the day was taken up with individual presentations, the content of which is summarised in the revised protocols. Other points that arose in discussion are as below:
The suggestion was made that a number of trial cores should be made at any one mire site and the one with the most variance selected, although to what extent this implied more information on past climate change or merely extra 'noise' was debatable.
The question was raised as to what was really being measured, but it was pointed out that at least the results were usually internally consistent. However, tests of replication done by personnel from Dublin between cores from the same site were apparently not so good.
At this stage a protocol for core description in the field was suggested but not pursued further at the meeting. The 'Troels-Smith' method was felt to be too complicated and not particularly useful for the purposes of ACCROTELM.
The transfer function derived from studies on UK bogs seemed to work reasonably well across Europe, but was not fully tested and might not prove totally satisfactory. Instructions for field sampling to establish a better transfer function would be circulated. This raised the question of the possibility of repeat visits to mire sites but in some cases (particularly the Faroes) this seemed unlikely. Dan also pointed out that the effects of snow cover on testate amoebae were not known, and that testates were sensitive to thickness of water film, pH (>5.5) being a secondary influence. He also noted that testate samples from the top 5 cm or so of the bog provided approximately a 5-year integration.
It was suggested that loss-on-ignition might be an acceptable substitute for bulk C/N analysis. Richard requested that samples destined for them should be frozen/freeze-dried as soon as possible.
The procedure to be followed was explained further, with reference to the workpackage description.
It was decided that samples should be pre-treated by the participants to save time/money. It was suggested that it might be possible to obtain additional dating from the UK NERC East Kilbride laboratory, and that all biomolecular dating would be done via (NERC-sponsored) Oxford laboratory..
Tephrochronology was only scheduled to be done on peat from the Faeroes, though John Hunt argued strongly that if the material and time are available we should conduct a search at other sites. SCPs would only be done on the top monolith of material; 210Pb dating would only help date the last 150 years of peat accumulation, so again would be done on the top monolith; samples to be submitted via University of Gloucestershire.
The process of changes in hummock and hollow configuration were discussed at length. In Estonia the occurrence of different periods of expansion/contraction of hollows was noted, together with the implication that this might give rise to changes in the core caused only by changing microtopography. However, it was felt that the centres of hummocks and hollows were relatively stable forms. There was also the conclusion that the development (in Estonia at least) of raised bogs from fens was not climate driven. In terms of coring sites it was suggested that the centre of a lawn area (although probably stable) was less suitable as lawn species seem to have higher ecological tolerances and would therefore produce less variation in the cores. Just inside the edge of a lawn area was favoured as a potentially good site provided there was good variation in the core. Certainly a number of trials would be necessary.
Hansjörg introduced this session and reminded participants of the limitations but also the potential of pollen analysis. Bas suggested that a selection of significant non-pollen microfossil types should be studied (approx. 5-10 types). Of course any treatment with HF should be avoided for these samples. Precise horizons should be defined with care as some organisms exist up to 1-2 cm below the vegetation layer - e.g. Type 10 (a mycorrhizal fungus) lives 1-2 cm below Calluna. As Michel Magny was not present, Bas presented (with the aid of a slide) a short summary of some of Michel's work.
The remainder of the morning was given over to a general discussion of the coring and sampling protocol. It was decided that sampling for humification should be contiguous at 1 cm resolution, except for the Faroes where a resolution of 0.5 cm was thought desirable. As well as replicate cores the desirability of a duplicate core at remote sites was discussed.
Groups and persons responsible for the various sites and the analyses at those sites were identified and confirmed. The UK site had changed to Butterburn Flow, owing to a conflict of interests at the original site, Walton Moss. The meeting asked if the site could be reinstated, but that did not seem likely.
After lunch the group left to assess coring techniques at Fenn's and Whixall Moss in Shropshire, which took place on the Wednesday morning. Here a method of 'back to back' replicate coring was tried. This employed a Russian corer rotated through 180º and pushed down through the same hole for the overlapping drives. It seemed fairly successful, but required further testing.
The meeting ended at lunch-time on Wednesday 30th April.
Proposed date of next meeting, to be held at the University of Helsinki: 26-28 April 2004