DISTRIBUTION ET FLUX DE L’AZOTE (N) DANS UN BASSIN VERSANT SOUMIS A LA RETENTION DES EAUX AU NIVEAU DES BARRAGES; CAS DU BASSIN DE SEYBOUSE (NORD-EST ALGERIEN)
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Date
2019
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Journal ISSN
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Publisher
Université Abbes Laghrour -Khenchela-
Abstract
Abstract
This study has covered for the first time the distribution and flow of nitrogen from
the Seybouse Basin during the period between September 2016 (dry season) and April
2017 (wet season). It is concerned with following the evolution of this element from the
upstream of the catchment up to the mouth in order to understand these biogeochemical
transformations under the effect of the dams and the estuary.
The results obtained show that the levels and fluxes of the different forms of NID
of Oued Seybouse are significantly modified along the aquatic continuum before
reaching the sea. Indeed, we find that:
- The sub-basin of foum elkhanga is richer in NID than that of Bouhamdane
- The 2 dams act as producers of the NID (30%)
- The estuary also behaves like a producer or the strong contents of 154μM on average
are recorded at the mouth
- The Foum Elkhanga dam produces annually 32 t/year. While the Bouhamdane dam
produces an annual flow of 4 times more (118 t /year).
- The estuarine part acts as a producer of 118 t/year in the wet season and consumes
12.4t/year (100%) of the NID during the dry period (closed mouth in the lagoon phase).
- The values of N/P are on average altered (48) at the mouth (enriched in nitrogen than
in phosphates).
- Si/P (13.5) and Si/N (0.4) values are low (enriched in nitrogen and phosphates than in
silicon)
- Si/N/P values deviate significantly from the equilibrium value in any season.
These hydrological and biogeochemical conditions are expected to have severe impacts
on the river system and on the functioning and production of the renewable resources of
the receiving littoral.