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Title: The dilemma of disappearing diatoms: incorporating diatom dissolution data into palaeoenvironmental modelling and reconstruction
Authors: Ryves, David B.
Battarbee, Richard W.
Fritz, Sherilyn C.
Issue Date: 2009
Publisher: © Elsevier
Citation: RYVES, D.B., BATTARBEE, R.W. and FRITZ, S.C., 2009. The dilemma of disappearing diatoms: incorporating diatom dissolution data into palaeoenvironmental modelling and reconstruction. Quaternary Science Reviews, 28 (1-2), pp.120-136.
Abstract: The problem of microfossil preservation, specifically diatom dissolution, remains an important, but often overlooked, source of error in both qualitative and quantitative reconstructions of key variables from fossil samples, especially those using relative abundance data. A first step to tackling this complex issue is establishing an objective method of assessing preservation (here, diatom dissolution) that can be applied by different analysts and incorporated into routine counting strategies. Here, we establish a methodology for assessment of diatom dissolution under standard light microscopy (LM) illustrated with morphological criteria for a range of major diatom valve shapes. Dissolution data can be applied to numerical models (transfer functions) from contemporary samples, and to fossil material to aid interpretation of stratigraphic profiles and taphonomic pathways of individual taxa. Using a surface sediment diatom-salinity training set from the Northern Great Plains (NGP) as an example, we explore a variety of approaches to including dissolution data in salinity inference models indirectly and directly. Results show that dissolution data can improve models, with apparent dissolution-adjusted error (RMSE) up to 15% lower that their unadjusted counterparts. Internal validation suggests improvements are more modest, with bootstrapped prediction errors (RMSEP) up to 10% lower. When tested on a short core from Devils Lake, North Dakota, which has a historical record of salinity, dissolution-adjusted models infer higher values compared to unadjusted models during peak salinity of the 1930s-40s Dust Bowl but nonetheless significantly underestimate peak values. Site-specific factors at Devils Lake associated with effects of lake level change on taphonomy (preservation and reworking, implied by dissolution data) may override model improvements incorporating dissolution.Dissolution-adjusted salinity models are also applied to a 150-yr sediment record from Spiritwood Lake, North Dakota, which suggests that this lake has a damped and lagged response to major regional climate forcing of salinity during the Dust Bowl. At this site, dissolution data also suggest different taphonomic behaviour of taxa related to their seasonal patterns of growth and sedimentation. Thus, dissolution data can improve models, and aid interpretation of sedimentary profiles as records of limnological, ecological and environmental change, filtered by taphonomy.
Description: This is the author’s version of a work that was submitted for publication in Quaternary Science Reviews. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published at: http://dx.doi.org/10.1016/j.quascirev.2008.08.021
Sponsor: Part of this work was carried out within NERC grant GR9/02033 to DBR and RWB, and additionally during a NERC studentship to DBR (GT4/90/ALS/28).
Version: Accepted for publication
DOI: 10.1016/j.quascirev.2008.08.021
URI: https://dspace.lboro.ac.uk/2134/14504
Publisher Link: http://dx.doi.org/10.1016/j.quascirev.2008.08.021
ISSN: 0277-3791
Appears in Collections:Published Articles (Geography and Environment)

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