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| Titel |
Two decades of inorganic carbon dynamics along the West Antarctic Peninsula |
| VerfasserIn |
C. Hauri, S. C. Doney, T. Takahashi, M. Erickson, G. Jiang, H. W. Ducklow |
| 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 ; 12, no. 22 ; Nr. 12, no. 22 (2015-11-26), S.6761-6779 |
| Datensatznummer |
250118180
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| Publikation (Nr.) |
 copernicus.org/bg-12-6761-2015.pdf |
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| Zusammenfassung |
| We present 20 years of seawater inorganic carbon measurements collected along
the western shelf and slope of the Antarctic Peninsula. Water column
observations from summertime cruises and seasonal surface underway pCO2
measurements provide unique insights into the spatial, seasonal, and
interannual variability in this dynamic system. Discrete measurements from
depths > 2000 m align well with World Ocean Circulation
Experiment observations across the time series and underline the consistency
of the data set. Surface total alkalinity and dissolved inorganic carbon data
showed large spatial gradients, with a concomitant wide range of
Ωarag (< 1 up to 3.9). This spatial variability was
mainly driven by increasing influence of biological productivity towards the
southern end of the sampling grid and meltwater input along the coast towards
the northern end. Large inorganic carbon drawdown through biological
production in summer caused high near-shore Ωarag despite
glacial and sea-ice meltwater input. In support of previous studies, we
observed Redfield behavior of regional C / N nutrient utilization, while
the C / P (80.5 ± 2.5) and N / P (11.7 ± 0.3) molar
ratios were significantly lower than the Redfield elemental stoichiometric
values. Seasonal salinity-based predictions of Ωarag suggest
that surface waters remained mostly supersaturated with regard to aragonite
throughout the study. However, more than 20 % of the predictions for
winters and springs between 1999 and 2013 resulted in Ωarag
< 1.2. Such low levels of Ωarag may have implications
for important organisms such as pteropods. Even though we did not detect any
statistically significant long-term trends, the combination of on\-going
ocean acidification and freshwater input may soon induce more unfavorable
conditions than the ecosystem experiences today. |
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