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| Titel |
Spring molybdenum enrichment in scallop shells: a potential tracer of diatom productivity in temperate coastal environments (Brittany, NW France) |
| VerfasserIn |
A. Barats, D. Amouroux, C. Pécheyran, L. Chauvaud, J. Thébault, 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 ; 7, no. 1 ; Nr. 7, no. 1 (2010-01-19), S.233-245 |
| Datensatznummer |
250004376
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| Publikation (Nr.) |
 copernicus.org/bg-7-233-2010.pdf |
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| Zusammenfassung |
| Skeletal molybdenum/calcium ([Mo]/[Ca])shell ratios were examined in
shells of the Great Scallop Pecten maximus collected in temperate coastal environments of
Western Europe (42 to 49° N). These ratios were determined by
quantitative LA-ICP-MS analyses of daily striae taken every third day (i.e.
a temporal resolution of 3 days) in 36 flat valves (2-years old; 3
shells/year). Variations of ([Mo]/[Ca])shell ratios were significant
and reproducible for scallops from the same population, from different years
(1998–2004) and temperate coastal locations (NW France). The
[Mo]/[Ca])shell ratios exhibit typical profiles characterized by a
background content, below the detection limit for this method
(<0.003 μmol/mol) for most of the shell growth period, which is punctuated by a
significant transient enrichment (0.031–2.1 μmol/mol) mainly occurring
from May to June. The Bay of Brest (France) was investigated in particular
because of its long term observations on scallop communities, environmental
variables, and high resolution analyses of dissolved Mo in bottom seawater
in 2000. In 2000, dissolved Mo exhibited a significant increase in
concentration just preceding the maximum ([Mo]/[Ca])shell ratio. Both
the intense monitoring survey in 2000 and over the 7-year period indicates
that the ([Mo]/[Ca])shell maximum is directly influenced by spring
changes of environmental conditions at the sediment water interface (SWI),
occurring subsequent to the intense and periodic spring bloom. Spring maxima
of ([Mo]/[Ca])shell ratios are closely correlated to the extent of
silicic acid and nitrate depletion in seawater between winter and late
spring (r2=0.878 and 0.780, p<0.05, n=6) that reflects diatom
uptake and productivity in the Bay of Brest. The Mo inputs in bottom waters
and subsequent shell enrichment are thus suggested to be directly or
indirectly influenced by such biogenic material input at the SWI. The
[Mo]/[Ca])shell records thus reveal unexpected biogeochemical cycles of
Mo influenced by coastal spring productivity, faithfully recorded in scallop
shells. |
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