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Spatial variation in pollen 13C correlates with temperature and seasonal development timing
N. J. Loader
Environmental Change Research Group, Department of Geography, University of Wales Swansea, Swansea SA2 8PP, UK; Laboratory of Tree-Ring Research, West Stadium Building 58, University of Arizona, AZ 85721, USA;n.j.loader{at}swansea.ac.uk
D. L. Hemming
Laboratory of Tree-Ring Research, West Stadium Building #58, University of Arizona, AZ 85721, USA; The Godwin Institute for Quaternary Research, University of Cambridge, Cambridge CB2 3SA, UK
Stable carbon isotope analyses were performed on the sporopollenin of modernPinus sylvestris pollen ( 13Cpollen) from a network of sites across Europe. A strong linear relationship (r2 = 0.68 P 0.001) is observed between 13Cpollen and mean temperature during the month prior to efflorescence. Although the duration of pollen development almost certainly varies between sites, these results support observations that the majority of pollen mass is accumulated during the last month of its formation and that the photosynthate used to form pollen has a 13C composition reflecting climatic conditions during this development period. When the 13Cpollen values are compared with mean annual temperature (MAT) or degrees latitude the data cluster around two regression lines. Both groups are positively correlated with temperature and decreasing latitude, one comprising pollen from sites north of 50°N while the other is composed of sites south of this. The slope of the regression line is steeper for the northern group, indicating stronger temperature sensitivity. The transition in 13Cpollen between the northern and southern groups coincides with a shift in the timing of the development period from May/June to April/May. The associated changes in development period tempera ture and 13Cpollen across this transition are from 15°C and25 for the most southern in the northern group to 9°C and30 for the most northern in the southern group. If these initial results are representative of Pinus sylvestris throughout its distribution, 13Cpollen of palaeorecords may be used to reconstruct past development period temperature and provide an indication of mean annual temperature.
Key Words: Pollen stable carbon isotope Pinus sylvestris palynology palaeoclimatic variation Europe
The Holocene, Vol. 11, No. 5,
587-592 (2001)
DOI: 10.1191/095968301680223530

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