 |
| Titel |
Does ocean acidification induce an upward flux of marine aggregates? |
| VerfasserIn |
X. Mari |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 5, no. 4 ; Nr. 5, no. 4 (2008-07-23), S.1023-1031 |
| Datensatznummer |
250002675
|
| Publikation (Nr.) |
 copernicus.org/bg-5-1023-2008.pdf |
|
|
|
|
|
| Zusammenfassung |
| The absorption of anthropogenic atmospheric carbon dioxide (CO2) by the
ocean provokes its acidification. This acidification may alter several
oceanic processes, including the export of biogenic carbon from the upper
layer of the ocean, hence providing a feedback on rising atmospheric carbon
concentrations. The effect of seawater acidification on transparent
exopolymeric particles (TEP) driven aggregation and sedimentation processes
were investigated by studying the interactions between latex beads and TEP
precursors collected in the lagoon of New Caledonia. A suspension of TEP and
beads was prepared and the formation of mixed aggregates was monitored as a
function of pH under increasing turbulence intensities. The pH was
controlled by addition of sulfuric acid. Aggregation and sedimentation
processes driven by TEP were drastically reduced when the pH of seawater
decreases within the expected limits imposed by increased anthropogenic
CO2 emissions. In addition to the diminution of TEP sticking
properties, the diminution of seawater pH led to a significant increase of
the TEP pool, most likely due to swollen structures. A diminution of
seawater pH by 0.2 units or more led to a stop or a reversal of the downward
flux of particles. If applicable to oceanic conditions, the sedimentation of
marine aggregates may slow down or even stop as the pH decreases, and the
vertical flux of organic carbon may reverse. This would enhance both rising
atmospheric carbon and ocean acidification. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|