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| Titel |
Atmospheric outflow of Nutrients to the Bay of Bengal: Impact of continental sources |
| VerfasserIn |
Manmohan Sarin, Bikkina Srinivas |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090903
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| Publikation (Nr.) |
 EGU/EGU2014-5163.pdf |
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| Zusammenfassung |
| The air-sea deposition of nutrients (N, P and Fe) to the oceanic regions located downwind of
pollution sources in south Asia is gaining considerable attention in the present-day scenario
of climate change. We report here a case study on the abundances of nutrients, their sources
and temporal variability in the atmospheric outflow from the Indo-Gangetic Plain (IGP) to
the Bay of Bengal (BoB). Air mass back trajectory analysis suggests conspicuous
downwind transport of chemical constituents from the IGP to BoB during the late
NE-monsoon (January-April). During rest of the year, wind-regimes do not favour the
atmospheric transport from the IGP, making BoB a unique oceanic region in the
global perspective. Concentrations of NO3-, NH4+, NOrg, PO43- and Fews in the
atmospheric outflow from the IGP, studied during November’09 – March’10, show
pronounced temporal variability. The inorganic nitrogen dominates (NH4+-N: ~ 90 % of
NInorg) the total soluble nitrogen (NTot). Although the contribution of organic
nitrogen is not significant, the mass ratio of NOrg/NTot in the outflow varied from
0.07 to 0.40. The abundances of PInorg and Fews varied from 0.4 to 4.8 nmol m-3
and 0.2 to 0.6 nmol m-3, respectively. The high abundance of K+and significant
(P-value < 0.05) correlation with PInorg suggests their dominant contribution from
biomass burning emissions. The concentration of aerosol iron (FeTot: 60–1144 ng
m-3), its fractional solubility (Fews %: 6.7 –26.5) and co-variability of Fews (%)
with nss-SO42- suggests chemical processing of alluvial dust during atmospheric
transport from the IGP. The characteristic mass ratios of nutrients (NInorg/NTot:
0.92 ± 0.13, NOrg/NTot: 0.21 ± 0.11, and PInorg/nss-Ca2+: 0.35 ± 0.23) in the
atmospheric outflow from the IGP show striking similarity with those reported over
the BoB. These results have implications to further increase in the atmospheric
deposition of nutrients and their impact on biogeochemistry of surface Bay of Bengal. |
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