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| Titel |
Seasonal dissolved inorganic nitrogen and phosphorus budgets for two sub-tropical estuaries in south Florida, USA |
| VerfasserIn |
C. Buzzelli, Y. Wan, P. H. Doering, J. N. Boyer |
| 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 ; 10, no. 10 ; Nr. 10, no. 10 (2013-10-24), S.6721-6736 |
| Datensatznummer |
250085377
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| Publikation (Nr.) |
 copernicus.org/bg-10-6721-2013.pdf |
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| Zusammenfassung |
| Interactions among geomorphology, circulation, and biogeochemical cycling
determine estuary responses to external nutrient loading. In order to better
manage watershed nutrient inputs, the goal of this study was to develop
seasonal dissolved inorganic nitrogen (DIN) and phosphorus (DIP) budgets for
the two estuaries in south Florida, the Caloosahatchee River estuary (CRE)
and the St. Lucie Estuary (SLE), from 2002 to 2008. The Land–Ocean Interactions
in the Coastal Zone (LOICZ) approach was used to generate water, salt, and
DIN and DIP budgets. Results suggested that internal DIN production increases
with increased DIN loading to the CRE in the wet season. There were
hydrodynamic effects as water column concentrations and ecosystem nutrient
processing stabilized in both estuaries as flushing time increased to
>10 d. The CRE demonstrated heterotrophy (net ecosystem metabolism or
NEM < 0.0) across all wet and dry season budgets. While the SLE was
sensitive to DIN loading, system autotrophy (NEM > 0.0) increased
significantly with external DIP loading. This included DIP consumption and a
bloom of a cyanobacterium (Microcystis aeruginosa) following
hurricane-induced discharge to the SLE in 2005. Additionally, while
denitrification provided a microbially-mediated N loss pathway for the CRE,
this potential was not evident for the SLE where N2 fixation was
favored. Disparities between total and inorganic loading ratios suggested
that the role of dissolved organic nitrogen (DON) should be assessed for both
estuaries. Nutrient budgets indicated that net internal production or
consumption of DIN and DIP fluctuated with inter- and intra-annual variations
in freshwater inflow, hydrodynamic flushing, and primary production. The
results of this study should be included in watershed management plans in
order to maintain favorable conditions of external loading relative to
internal material cycling in both dry and wet seasons. |
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