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| Titel |
High frequency Barium profiles in shells of the Great Scallop Pecten maximus: a methodical long-term and multi-site survey in Western Europe |
| VerfasserIn |
A. Barats, D. Amouroux, L. Chauvaud, C. Pécheyran, A. Lorrain, J. Thébault, T. M. Church, O. F. X. Donard |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 2 ; Nr. 6, no. 2 (2009-02-10), S.157-170 |
| Datensatznummer |
250003427
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| Publikation (Nr.) |
 copernicus.org/bg-6-157-2009.pdf |
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| Zusammenfassung |
| Skeletal barium/calcium ([Ba]/[Ca])shell ratios were measured every
third daily striae in 39 flat valves of the Great Scallop Pecten maximus collected in
temperate coastal environments of Western Europe. A methodical evaluation of
the ([Ba]/[Ca])shell ratio was performed for the first time and
demonstrates that ([Ba]/[Ca])shell profiles are reproducible for
several scallop individuals from the same population (2-year old; 3
shells/year), over a 7-year period (1998–2004), and from different coastal
environments in France (42–49° N). As previously determined in the shells
of other bivalve species, ([Ba]/[Ca])shell profiles generally exhibited
a background ratio punctuated by two transient maxima occurring in early and
late summer. Background partition coefficient (DBa=0.11±0.03,
in 2000) was similar to that previously reported in P. maximus shells, suggesting a
direct shell uptake of dissolved seawater Ba (Gillikin et al.,
2008). The 7-year survey in the Bay of Brest of the high frequency
([Ba]/[Ca])shell profiles in the scallop's shell was exploited to
better constrain both the occurrence and the amplitude of the summer Ba
relative enrichments as influenced by environmental processes. Seawater Ba
contents in 2000 underlined significant particulate Ba inputs at the
sediment water interface (SWI) during ([Ba]/[Ca])shell peak events.
These Ba inputs are thus suggested to be subsequently induced by a pelagic
biogenic process, which mainly occurs under summer post-bloom conditions in
relationship to the cycling of particulate organic matter and associated Ba.
The long term survey reveals that such pelagic Ba cycling processes are
responsible for particulate Ba inputs to the sediment water interface (SWI).
Subsequent indirect Ba uptake by the bivalve results in higher
([Ba]/[Ca])shell ratios, in that archived Ba within the shell cannot be
used as a direct paleo productivity tracer. Our methodical approach, based
on a multi-year and multi-site-survey of ([Ba]/[Ca])shell ratio in
Scallop bivalves, allows us to establish the potential application of such
high frequency archives for further biogeochemical and ecological
investigations of bivalves in the coastal environment. |
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