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| Titel: |
Distribution, origin and cycling of carbon in the Tana River (Kenya): a dry season basin-scale survey from headwaters to the delta |
| Auteur: |
S. Bouillon G. Abril A. V. Borges F. Dehairs G. Govers H. J. Hughes R. Merckx F. J. R. Meysman J. Nyunja C. Osburn J. J. Middelburg |
| Verschenen in: |
Biogeosciences |
| Paginering: | Jaargang 6 (2009) nr. 11 pagina's 2475-2493 |
| Jaar: |
2009 |
| Inhoud: |
The Tana River basin (TRB) is the largest in Kenya (~120 000 km<sup>2). We conducted a survey during the dry season throughout the TRB, analyzing a broad suite of biogeochemical parameters. Biogeochemical signatures in headwater streams were highly variable. Along the middle and lower river course, total suspended matter (TSM) concentrations increased more than 30-fold despite the absence of tributary inputs, indicating important resuspension events of internally stored sediment. These resuspended sediment inputs were characterized by a lower and <sup>14C-depleted OC content, suggesting selective degradation of more recent material during sediment retention. Masinga Dam (a large reservoir on the upper river) induced a strong nutrient retention (~50% for inorganic N, ~72% for inorganic phosphate, and ~40% for dissolved silicate). Moreover, while DOC pools and δ<sup>13C signatures were similar above, in and below the reservoir, the POC pool in Masinga surface waters was dominated by <sup>13C-depleted phytoplankton, which contributed to the riverine POC pool immediately below the dam, but rapidly disappeared further downstream, suggesting rapid remineralization of this labile C pool in the river system. Despite the generally high turbidity, the combination of relatively high oxygen saturation levels, low δ<sup>18O signatures of dissolved O2 (all <+24.2‰), and the relatively low pCO2 values suggest that in-stream primary production was significant, even though pigment data suggest that phytoplankton makes only a minor contribution to the total POC pool in the Tana River. |
| Uitgever: |
Copernicus GmbH (provided by DOAJ) |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 9 van 27 gevonden artikelen
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