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| Titel |
Eutrophication mitigation in rivers: 30 years of trends in spatial and seasonal patterns of biogeochemistry of the Loire River (1980–2012) |
| VerfasserIn |
C. Minaudo, M. Meybeck, F. Moatar, N. Gassama, F. Curie |
| 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 ; 12, no. 8 ; Nr. 12, no. 8 (2015-04-30), S.2549-2563 |
| Datensatznummer |
250117918
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| Publikation (Nr.) |
 copernicus.org/bg-12-2549-2015.pdf |
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| Zusammenfassung |
| Trends and seasonality analysis from 1980 onward and longitudinal
distribution,
from headwaters to estuary, of chlorophyll a, nitrate and phosphate were
investigated in the eutrophic Loire River. The continuous decline of
phosphate concentrations which has been recorded since 1991 both in the main river and in
the tributaries has led to the conclusion that it was responsible for the
significant reduction in phytoplanktonic biomass across the whole river
system, although Corbicula spp. clams invaded the river during the same period and
probably played a significant role in the phytoplankton decline. While
eutrophication remained lower in the main tributaries than in the Loire
itself, they were found to contribute up to ≈ 35% to the total
nutrient load of the main river. The seasonality analysis revealed
significant seasonal variations for the different eutrophication metrics and
calls into question the classical monthly survey recommended by national or
international authorities. Reducing P inputs impacted these seasonal
variations: the decline of seasonal amplitudes of chlorophyll a reduced the
seasonal amplitude of orthophosphate and of daily variations of dissolved
oxygen and pH but did not significantly affect the seasonal amplitude of
nitrate. Thus, the influence of phytoplankton on seasonal variations of
nitrate was minor throughout the period of study. |
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