Hydrologic and topographic controls on storm-event exports of dissolved organic carbon (DOC) and nitrate across catchment scales

نویسندگان

  • Shreeram P. Inamdar
  • Myron J. Mitchell
چکیده

[1] Patterns of DOC and nitrate (NO3 ) concentrations and fluxes were studied for six storm events across four forested, glaciated, subcatchments (1.6 to 696 ha) in western New York, USA. End-member mixing analysis (EMMA) showed that catchment runoff was composed of shallow groundwater (SGW) discharged at seeps and throughfall (THF) on the rising limb and THF and riparian water (RW) on the recession limb. High THF NO3 contributions produced a pronounced rise and maximum in streamflow NO3 , while low THF concentrations resulted in a dilution trajectory. We did not find any evidence for NO3 flushing by a rising water table. We propose an alternate model for NO3 where the occurrence of seeps and steep slope gradients are the primary determinants of NO3 generation and delivery, and VSAs or saturated areas have a secondary role as loci for interception of NO3 contributions from throughfall. Exports of DOC from the catchments were attributed to THF contributions and the flushing of riparian and hillslope-bench saturated areas. Concentrations of DOC increased with increasing catchment size and percent-saturated area whereas NO3 values showed an opposite trend. Concentrations of DOC from a wetland catchment were consistently high, but higher percent increases in event DOC concentration were observed for those catchments with riparian and hillslopebench saturated areas. Catchments dominated by riparian zones and catchments with discrete, distal wetlands may have substantial untapped stores of DOC, which become mobilized during high moisture conditions. Thus wetlands in steeply incised valleys may not be effective in buffering hillslope solute loadings.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Storm event exports of dissolved organic nitrogen (DON) across multiple catchments in a glaciated forested watershed

[1] Storm event patterns of dissolved organic nitrogen (DON) were studied for multiple events across four catchments (1.6–696 ha) in a forested, glaciated watershed in western New York State. Highest concentrations of DON in the watershed were recorded for litter leachate followed by throughfall. Storm event concentrations of DON consistently peaked at or before peak discharge while dissolved o...

متن کامل

Export mechanisms for dissolved organic carbon and nitrate during summer storm events in a glaciated forested catchment in New York, USA

Nitrate and dissolved organic carbon (DOC) concentrations during a summer storm for a forested catchment in the Adirondack Mountains displayed a clear separation in trajectories and timing of maximum values. Nitrate concentrations peaked early on the rising limb of the hydrograph, whereas DOC concentrations gradually increased through the rising limb with maximum concentrations following the di...

متن کامل

Variability of DOC and nitrate responses to storms in a small Mediterranean forested catchment

Severe drought periods followed by intense rainfall often leads to major floods in Mediterranean catchments. The resulting hydrology is complex and the response of solutes in the streams is often unpredictable. This study aimed to identify the most relevant factors controlling the hydrological responses to storms of an intermittent Mediterranean stream and to link those factors with dissolved o...

متن کامل

Fluvial organic carbon flux from an eroding peatland catchment, southern Pennines, UK

This study investigates for the first time the relative importance of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the fluvial carbon flux from an actively eroding peatland catchment in the southern Pennines, UK. Event scale variability in DOC and POC was examined and the annual flux of fluvial organic carbon was estimated for the catchment. At the event scale, both DO...

متن کامل

Importance of seasonality and small streams for the landscape regulation of dissolved organic carbon export

[1] The regulation of the spatial and seasonal variation in terrestrial dissolved organic carbon (DOC) exports was studied in a 68 km boreal stream system in northern Sweden. A total of 1213 DOC samples were collected in 15 subcatchments over a 3 year period (2003–2005). The mean annual DOC exports from the 15 subcatchments (0.03–21.72 km) ranged from 14.8 to 99.1 kg ha 1 yr . Many catchment ch...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2006