A novel palaeoaltimetry proxy based on spore and pollen wall chemistry

Lomax, Barry H.; Fraser, Wesley T.; Harrington, Guy J.; Blackmore, Stephen; Sephton, Mark A.; Harris, Nigel

doi:10.1016/j.epsl.2012.07.039

Cited by 35 publications

(59 citation statements)

References 74 publications

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“…This is of importance since the concentration of phenylpropanoid components in wall biopolymers can be used as UV-B proxy and changes in the flux of UV-B radiation can be tracked over geological time (Lomax et al 2012). Therefore, the aim of this study was to investigate to what extend FTIR and Raman microspectroscopy measurements can reveal spatially resolved chemical information of pure grain biopolymers of Pinaceae pollen.…”

Section: Introductionmentioning

confidence: 99%

Vibrational microspectroscopy enables chemical characterization of single pollen grains as well as comparative analysis of plant species based on pollen ultrastructure

Zimmermann

Bağcıoğlu

Sandt

et al. 2015

Planta

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Main conclusion: Chemical imaging of pollen by vibrational microspectroscopy enables characterization of pollen ultrastructure, in particular phenylpropanoid components in grain wall for comparative study of extant and extinct plant species.Keywords: FTIR microspectroscopy, Raman microspectroscopy, Pinales, imaging, cell wall. 2 SUMMARYA detailed characterization of conifer (Pinales) pollen by vibrational microspectroscopy is presented. The main problems that arise during vibrational measurements were scatter and saturation issues in Fourier transform infrared (FTIR), and fluorescence and penetration depth issues in Raman. Single pollen grains larger than approx. 15 µm can be measured by FTIR microspectroscopy using conventional light sources, while smaller grains may be measured by employing synchrotron light sources. Pollen grains that were larger than 50 µm were too thick for FTIR imaging since the grain constituents absorbed almost all infrared light. Chemical images of pollen were obtained on sectioned samples, unveiling the distribution and concentration of proteins, carbohydrates, sporopollenins and lipids within pollen substructures. The comparative analysis of pollen species revealed that, compared with other Pinales pollens, Cedrus atlantica has a higher relative amount of lipid nutrients, as well as different chemical composition of grain wall sporopollenin. The pre-processing and data analysis, namely extended multiplicative signal correction and principal component analysis, offer simple estimate of imaging spectral data and indirect estimation of physical properties of pollen. The vibrational microspectroscopy study demonstrates that detailed chemical characterization of pollen can be obtained by measurement of an individual grain and pollen ultrastructure. Measurement of phenylpropanoid components in pollen grain wall could be used, not only for the reconstruction of past environments, but for assessment of diversity of plant species as well. Therefore, analysis of extant and extinct pollen species by vibrational spectroscopies is suggested as a valuable tool in biology, ecology and palaeosciences.3

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Section: Introductionmentioning

confidence: 99%

Vibrational microspectroscopy enables chemical characterization of single pollen grains as well as comparative analysis of plant species based on pollen ultrastructure

Zimmermann

Bağcıoğlu

Sandt

et al. 2015

Planta

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“…Indicators of solar activity such as counts of sunspot numbers and cosmogenic radionuclides ( 10 Be and 14 C) are limited to timescales of 10 2 to 10 3 years, respectively1, but the relationship between solar activity and UV flux is uncertain4. Calculated TSI variability across Milankovitch orbital cycles10 provides an expected pattern for incoming UV radiation over timescales of 10 4 to 10 7 years, but cannot detect short-term, surface-level departures from the orbital signal, for example those due to ozone thinning9, volcanic events11, dust clouds from bolide impacts12, or continental uplift13. A direct proxy for palaeo-UV flux would therefore provide both an indicator of UV as a climatic, environmental, and evolutionary forcing mechanism, and a recorder of atmospheric change across some of the major perturbations in Earth history.…”

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confidence: 99%

“…Within sporopollenin, protection from the deleterious effects of UV-B is provided by the phenolic compounds para -coumaric acid and ferulic acid1516. These UV absorbing compounds (UACs) covary with UV irradiance in a range of modern settings131516171819, demonstrating that plants actively control the chemical composition of sporopollenin with up-regulation in UACs in response to elevated UV doses16. The high preservation potential of sporopollenin, and the resultant high abundances of sporomorphs in the fossil record, suggests that a UAC-based proxy could be used to reconstruct UV flux in deep time settings1620.…”

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confidence: 99%

“…Using FTIR microspectroscopy we have measured UACs in Lycopodium (club moss) spores from 217 individual plants spanning a TSI range of 200 W/m 2 (see Methods). Lycopodium is an ideal taxon for assessing latitudinal trends in UAC concentrations because (a) it is geographically and latitudinally widespread; (b) its chemistry is well-understood from previous research on UV perception and reconstruction1315171821; and (c) the morphology of the plants, with sporangia facing upwards, means that the developing spores receive a clear UV signal. Encouragingly there is a strong positive relationship between UAC abundance in Lycopodium spores and TSI flux (Fig.…”

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confidence: 99%

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Pollen and spores as biological recorders of past ultraviolet irradiance

Jardine

Fraser

Lomax

et al. 2016

Sci Rep

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Solar ultraviolet (UV) irradiance is a key driver of climatic and biotic change. Ultraviolet irradiance modulates stratospheric warming and ozone production, and influences the biosphere from ecosystem-level processes through to the largest scale patterns of diversification and extinction. Yet our understanding of ultraviolet irradiance is limited because no method has been validated to reconstruct its flux over timescales relevant to climatic or biotic processes. Here, we show that a recently developed proxy for ultraviolet irradiance based on spore and pollen chemistry can be used over long (105 years) timescales. Firstly we demonstrate that spatial variations in spore and pollen chemistry correlate with known latitudinal solar irradiance gradients. Using this relationship we provide a reconstruction of past changes in solar irradiance based on the pollen record from Lake Bosumtwi in Ghana. As anticipated, variations in the chemistry of grass pollen from the Lake Bosumtwi record show a link to multiple orbital precessional cycles (19–21 thousand years). By providing a unique, local proxy for broad spectrum solar irradiance, the chemical analysis of spores and pollen offers unprecedented opportunities to decouple solar variability, climate and vegetation change through geologic time and a new proxy with which to probe the Earth system.

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“…Pollen size has also been correlated with genome size and may indicate polyploidy (three or more chromosome sets) in plants (Gould 1957;Kapadia & Gould 1964;Bennett 1972;Tate et al 2005;Knight et al 2010;De Storme et al 2013). Increasingly, geochemical studies utilising pollen, such as stable isotope analysis for palaeoclimate reconstructions (Amundson et al 1997;Loader & Hemming 2004;Nelson et al 2006Nelson et al , 2007King et al 2012;Nelson 2012;Bell et al 2017) and biomarker analysis for UV-B reconstructions (Rozema et al 2001(Rozema et al , 2002Fraser et al 2011;Willis et al 2011;Lomax et al 2012;, require detailed knowledge of grain size for developing techniques to isolate specific grains from fossil assemblages. For example, the use of micro-sieving to concentrate pollen from sediment (Heusser & Stock 1984;Brown et al 1989) can be modified to target grains within a specified size range to facilitate the isolation of pollen for specific species.…”

Section: Introductionmentioning

confidence: 99%

Cedrus atlantica pollen morphology and investigation of grain size variability using laser diffraction granulometry

et al. 2017

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The morphology and size variability of pollen grains of Cedrus atlantica were investigated using a novel approach employing laser diffraction granulometry. We provide new insights into size variability and present high-quality light microscopy (LM) and scanning electron microscopy (SEM) imagery of Cedrus atlantica pollen. Grains have an average size of 59.1 § 4.0 mm, measured on millions of grains from 91 samples. Analysis showed there is high variability of grain size within individual samples, although variability between samples is not significant. We found no significant relationships between grain size and climate (including temperature, precipitation and aridity), and suggest that grain size of fossil Cedrus pollen would not be a good proxy for climate reconstruction. Grain size may be influenced by a number of complex factors such as genome size or adaptations to support wind pollination, while variability within individual samples may result from the irregular development of pollen. The laser diffraction method produced repeatable, robust measurements on millions of pollen grains which are highly correlated with measurements taken using LM (r = 0.91, p = 0.002). Where grain size information is crucial for pollen identification, for developing isolation techniques for geochemical analysis, for investigating climatic and environmental influence, or for investigating links between genomes and grain size, particle size analysis by laser diffraction provides a reproducible and robust method for quickly determining pollen grain size on many samples.

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A novel palaeoaltimetry proxy based on spore and pollen wall chemistry

Cited by 35 publications

References 74 publications

Vibrational microspectroscopy enables chemical characterization of single pollen grains as well as comparative analysis of plant species based on pollen ultrastructure

Vibrational microspectroscopy enables chemical characterization of single pollen grains as well as comparative analysis of plant species based on pollen ultrastructure

Pollen and spores as biological recorders of past ultraviolet irradiance

Cedrus atlantica pollen morphology and investigation of grain size variability using laser diffraction granulometry

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