 |
| Titel |
Joint effect of freshwater plume and coastal upwelling on phytoplankton growth off the Changjiang River |
| VerfasserIn |
Y.-F. Tseng, J. Lin, M. Dai, S.-J. Kao |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 2 ; Nr. 11, no. 2 (2014-01-28), S.409-423 |
| Datensatznummer |
250117150
|
| Publikation (Nr.) |
 copernicus.org/bg-11-409-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| The Changjiang (Yangtze) River discharges vast amount of unbalanced nutrients (dissolved
inorganic nitrogen and phosphorus with N / P ratio > 80 in general) into
the East China Sea in summer. To study nutrient dynamics and P-stress
potential for phytoplankton, a cruise was conducted in the Changjiang plume
during summer 2011. With 3-D observations of nutrients, chlorophyll a
(Chl a), and bulk alkaline phosphatase activity (APA), we concluded that
the Changjiang Diluted Water and coastal upwelling significantly influenced
the horizontal and vertical heterogeneities of phytoplankton P deficiency in
the Changjiang plume. Allochthonous APA was detected at nutrient-enriched
freshwater end. Excessive N (~ 10 to 112 μM) was observed
throughout the entire plume surface. In the plume fringe featuring
stratification and excess N, diapycnal phosphate supply was blocked and
phytoplankton APA was stimulated for growth. We observed an upwelling just
attaching to the turbidity front at seaward side where Chl a peaked yet
much less APA was detected. An external phosphate supply from subsurface,
which promoted phytoplankton growth but inhibited APA, was suggested to be
sourced from the Nearshore Kuroshio Branch Current. In the so hydrographically
complicated Changjiang plume, phosphate supply instead of its concentration
may be more important in determining the expression of APA. Meanwhile,
allochthonous APA may also alter the usefulness of APA as a P-stress
indicator. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|