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| Titel |
Assessing net community production in a glaciated Alaskan fjord |
| VerfasserIn |
S. C. Reisdorph, J. T. Mathis |
| 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. 17 ; Nr. 12, no. 17 (2015-09-03), S.5185-5198 |
| Datensatznummer |
250118083
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| Publikation (Nr.) |
 copernicus.org/bg-12-5185-2015.pdf |
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| Zusammenfassung |
| The impact of deglaciation in Glacier Bay has been observed to seasonally
influence the biogeochemistry of this marine system. The influence from
surrounding glaciers, particularly tidewater glaciers, has the potential to
affect the efficiency and structure of the marine food web within Glacier
Bay. To assess the magnitude and the spatial and temporal variability in net
community production in a glaciated fjord, we measured dissolved inorganic
carbon, inorganic macronutrients, dissolved oxygen, and particulate organic
carbon between July 2011 and July 2012 in Glacier Bay, Alaska. High net
community production rates were observed across the bay (~ 54
to ~ 81 mmol C m−2 d−1) between the summer and fall
of 2011. However, between the fall and winter, as well as between the winter
and spring of 2012, air–sea fluxes of carbon dioxide and organic matter
respiration made net community production rates negative across most of the
bay as inorganic carbon and macronutrient concentrations returned to
pre-bloom levels. The highest organic carbon production occurred within the
west arm between the summer and fall of 2011 with ~ 4.5 × 105 kg C d−1. Bay-wide, there was carbon production of
~ 9.2 × 105 g C d−1 between the summer and fall.
Respiration and air–sea gas exchange were the dominant drivers of carbon
chemistry between the fall and winter of 2012. The substantial spatial and
temporal variability in our net community production estimates may reflect
glacial influences within the bay, as meltwater is depleted in
macronutrients relative to marine waters entering from the Gulf of Alaska in
the middle and lower parts of the bay. Further glacial retreat will likely
lead to additional modifications in the carbon biogeochemistry of Glacier
Bay, with unknown consequences for the local marine food web, which includes
many species of marine mammals. |
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