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| Titel |
The influence of hypercapnia and the infaunal brittlestar Amphiura filiformis on sediment nutrient flux – will ocean acidification affect nutrient exchange? |
| VerfasserIn |
H. L. Wood, S. Widdicombe, J. I. Spicer |
| 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. 10 ; Nr. 6, no. 10 (2009-10-06), S.2015-2024 |
| Datensatznummer |
250004029
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| Publikation (Nr.) |
 copernicus.org/bg-6-2015-2009.pdf |
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| Zusammenfassung |
| Rising levels of atmospheric carbon dioxide and the concomitant
increased uptake of this by the oceans is resulting in hypercapnia-related
reduction of ocean pH. Research focussed on the direct effects of these
physicochemical changes on marine invertebrates has begun to improve our
understanding of impacts at the level of individual physiologies. However,
CO2-related impairment of organisms' contribution to
ecological or ecosystem processes has barely been addressed. The burrowing
ophiuroid Amphiura filiformis, which has a
physiology that makes it susceptible to reduced pH, plays a key role in
sediment nutrient cycling by mixing and irrigating the sediment, a process
known as bioturbation. Here we investigate the role of A.
filiformis in modifying nutrient flux rates across the
sediment-water boundary and the impact of CO2- related
acidification on this process. A 40 day exposure study was conducted under
predicted pH scenarios from the years 2100 (pH 7.7) and 2300 (pH 7.3), plus
an additional treatment of pH 6.8. This study demonstrated strong
relationships between A. filiformis density and
cycling of some nutrients; activity
increases the sediment uptake of phosphate and the release of nitrite and
nitrate. No relationship between A. filiformis
density and the flux of ammonium or silicate were observed. Results also
indicated that, within the timescale of this experiment, effects at the
individual bioturbator level appear not to translate into reduced ecosystem
influence. However, long term survival of key bioturbating species is far
from assured and changes in both bioturbation and microbial processes could
alter key biogeochemical processes in future, more acidic oceans. |
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