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| Titel |
Salinization alters fluxes of bioreactive elements from stream ecosystems across land use |
| VerfasserIn |
S. Duan, S. S. Kaushal |
| 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. 23 ; Nr. 12, no. 23 (2015-12-15), S.7331-7347 |
| Datensatznummer |
250118214
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| Publikation (Nr.) |
 copernicus.org/bg-12-7331-2015.pdf |
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| Zusammenfassung |
| There has been increased salinization of fresh water over decades due to the
use of road salt deicers, wastewater discharges, saltwater intrusion,
human-accelerated weathering, and groundwater irrigation. Salinization can
mobilize bioreactive elements (carbon, nitrogen, phosphorus, sulfur)
chemically via ion exchange and/or biologically via influencing of microbial
activity. However, the effects of salinization on coupled biogeochemical
cycles are still not well understood. We investigated potential impacts of
increased salinization on fluxes of bioreactive elements from stream
ecosystems (sediments and riparian soils) to overlying stream water and
evaluated the implications of percent urban land use on salinization
effects. Two-day incubations of sediments and soils with stream and
deionized water across three salt levels were conducted at eight routine monitoring
stations across a land-use gradient at the Baltimore Ecosystem Study
Long-Term Ecological Research (LTER) site in the Chesapeake Bay watershed.
Results indicated (1) salinization typically increased sediment releases of
labile dissolved organic carbon (DOC), dissolved inorganic carbon (DIC),
total dissolved Kjeldahl nitrogen (TKN) (ammonium + ammonia + dissolved
organic nitrogen), and sediment transformations of nitrate; (2) salinization
generally decreased DOC aromaticity and fluxes of soluble reactive
phosphorus from both sediments and soils; (3) the effects of increased
salinization on sediment releases of DOC and TKN and DOC quality increased
with percentage watershed urbanization. Biogeochemical responses to
salinization varied between sediments and riparian soils in releases of DOC
and DIC, and nitrate transformations. The differential responses of riparian
soils and sediments to increased salinization were likely due to differences
in organic matter sources and composition. Our results suggest that
short-term increases in salinization can cause releases of significant
amounts of labile organic carbon and nitrogen from stream substrates and
organic transformations of nitrogen and phosphorus in urban watersheds.
Given that salinization of fresh water will increase in the future due to
human activities, significant impacts on carbon and nutrient mobilization
and water quality should be anticipated. |
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