Volume 402, 8 May 2015, Pages 125–139
- a Institute of Ecological Problems of the North of Ural Branch of Russian Academy of Sciences, Arkhangelsk 163000, Russia
- b Georesources and Environment Toulouse UMR 5563 CNRS, IRD, University of Toulouse, 14 Avenue Edouard Belin, 31400 Toulouse, France
- c BIO-GEO-CLIM Laboratory, Tomsk State University, Tomsk, Russia
- Received 13 June 2014, Revised 29 January 2015, Accepted 8 March 2015, Available online 17 March 2015
- Editor: M.E. Böttcher
Highlights
- •
- Four factors control Ca-normalized TE distribution in freshwater shells.
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- Element concentration and biochemical affinity are the first two factors.
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- Landscape and the proximity to hydrothermal/volcanic sources are the two other factors.
- •
- All species are significantly enriched by Mn relative to the river water.
- •
- TE distribution coefficients between the shells and water are similar for five species.
Abstract
To
reveal the geographical and inter-species variability of the major and
trace element (TE) compositions of freshwater mussel shells across
Eurasia, we used ICP MS after acid digestion to analyze 50 samples of
shells from five species of the genus Margaritifera spp.
(Bivalvia: Margaritiferidae) collected in 20 minor rivers located in NW
Russia, Sakhalin, Amur basin, Kuril Islands, Kamchatka and Laos. The
variations between replicates from the same site were smaller than the
variations between samples from different localities or between
different mollusk species. Using normed PCA, we observed significant
biological and geographical controls of the trace element composition in
freshwater shells, with five main species exhibiting distinct features
of TE concentration corresponding to four major geographical locations.
Four PCA factors explain 81% of the TE variability, which is closely
linked to specific geographical location and weakly linked to the
identity of the species. The first two factors (F1 × F2) are the element
concentration and its biological affinity. The other two factors
(F3 × F4) likely are the nutrient status of the river, corresponding to
its proximity to wetlands or mountains, and the degree of the influence
of volcanic/hydrothermal activity. The analysis of water samples
collected during the active growth period in summer baseflow was used to
quantify the distribution coefficients (Kd) of
trace elements between the aragonite shells and the river water. All
species are significantly enriched in Mn relative to the river water,
with distribution coefficients of up to 5. The other elements exhibit Kd
values that were similar for the five species. This suggests that the
obtained distribution coefficients may be universal constants reflecting
uptake of each element by the organism from the river water and its
intracellular transport and biocalcification processes. Taken together,
the chemical composition data for pearl mussel shells may not only
reflect the geographical locality and species identity but also provide
insights into biochemical processes of element uptake in the form of
biominerals.
Graphical abstract
Keywords
- Bivalve mussels;
- Margaritifera;
- Trace element;
- Eurasia;
- Distribution coefficient
