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| Titel |
The elemental composition of purple sea urchin (Strongylocentrotus purpuratus) calcite and potential effects of pCO2 during early life stages |
| VerfasserIn |
M. LaVigne, T. M. Hill, E. Sanford, B. Gaylord, A. D. Russell, E. A. Lenz, J. D. Hosfelt, M. K. Young |
| 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 ; 10, no. 6 ; Nr. 10, no. 6 (2013-06-01), S.3465-3477 |
| Datensatznummer |
250018263
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| Publikation (Nr.) |
 copernicus.org/bg-10-3465-2013.pdf |
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| Zusammenfassung |
| Ocean acidification will likely have negative impacts on invertebrates
producing skeletons composed of calcium carbonate. Skeletal solubility is
partly controlled by the incorporation of "foreign" ions (e.g. magnesium)
into the crystal lattice of these skeletal structures, a process that is
sensitive to a variety of biological and environmental factors. Here we
explore effects of life stage, oceanographic region of origin, and changes in
the partial pressure of carbon dioxide in seawater (pCO2) on trace
elemental composition in the purple sea urchin (Strongylocentrotus
purpuratus). We show that, similar to other urchin taxa, adult purple sea
urchins have the ability to precipitate skeleton composed of a range of
biominerals spanning low- to high-Mg calcites. Mg / Ca and Sr / Ca ratios
were substantially lower in adult spines compared to adult tests. On the
other hand, trace elemental composition was invariant among adults collected
from four oceanographically distinct regions spanning a range of carbonate
chemistry conditions (Oregon, Northern California, Central California, and
Southern California). Skeletons of newly settled juvenile urchins that
originated from adults from the four regions exhibited intermediate Mg / Ca
and Sr / Ca between adult spine and test endmembers, indicating that
skeleton precipitated during early life stages is more soluble than adult
spines and less soluble than adult tests. Mean skeletal Mg / Ca or
Sr / Ca of juvenile skeleton did not vary with source region when larvae
were reared under present-day, global-average seawater carbonate conditions
(400 μatm; pHT = 8.02 ± 0.03 1 SD;
Ωcalcite = 3.3 ± 0.2 1 SD). However, when reared under
elevated pCO2 (900 μatm; pHT = 7.73 ± 0.03;
Ωcalcite = 1.8 ± 0.1), skeletal Sr / Ca in juveniles
exhibited increased variance across the four regions. Although larvae from
the northern populations (Oregon, Northern California, Central California)
did not exhibit differences in Mg or Sr incorporation under elevated
pCO2 (Sr / Ca = 2.10 ± 0.06 mmol mol−1;
Mg / Ca = 67.4 ± 3.9 mmol mol−1), juveniles of Southern
California origin partitioned ~8% more Sr into their skeletons
when exposed to higher pCO2
(Sr / Ca = 2.26 ± 0.08 vs. 2.09 ± 0.005 mmol mol−1 1 SD).
Together these results suggest that the diversity of carbonate minerologies
present across different skeletal structures and life stages in purple sea
urchins does not translate into an equivalent geochemical plasticity of
response associated with geographic variation or temporal shifts in seawater
properties. Rather, composition of S. purpuratus skeleton
precipitated during both early and adult life history stages appears
relatively robust to spatial gradients and predicted future changes in
carbonate chemistry. An exception to this trend may arise during early life
stages, where certain populations of purple sea urchins may alter skeletal
mineral precipitation rates and composition beyond a given pCO2
threshold. This potential for geochemical plasticity during early development
in contrast to adult stage geochemical resilience adds to the growing body of
evidence that ocean acidification can have differing effects across
organismal life stages. |
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