Seasonal patterns in streamwater nutrient and dissolved organic carbon concentrations: Separating catchment flow path and in‐stream effects

Mulholland, Patrick J.; Hill, Walter R.

doi:10.1029/97wr00490

Cited by 253 publications

(250 citation statements)

References 55 publications

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“…These changes were especially evident within the high damage zone (600-740 m elevation), and apparent to a lesser extent at lower elevations where the canopy damage was less severe. Seasonal variation in light penetration and organic matter input can strongly influence patterns of nutrient uptake in streams (12,26,27). Thus, large-scale canopy damage should be expected to lead to even more dramatic changes in stream nutrient cycling, because of prolonged impacts on light penetration and organic matter availability.…”

Section: Resultsmentioning

confidence: 99%

In-stream uptake dampens effects of major forest disturbance on watershed nitrogen export

Bernhardt

Likens

Buso

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

154

134

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O ne of the major findings of the long-term Hubbard BrookEcosystem Study is that disturbance of northern hardwood forests results in increased watershed losses of nitrogen (primarily as NO 3 Ϫ ) (1-4). Nitrate export to stream water increases after deforestation because of reduced plant uptake, and increased rates of N mineralization and nitrification in upland soils (1, 4). Dramatic increases in streamwater NO 3 Ϫ fluxes followed whole watershed deforestation experiments in 1965-1968, 1974 -1976 , and 1983. Despite differences in the severity of the deforestation treatment, all watersheds showed a similar pattern of nitrogen loss (3, 5). After a winter cutting or logging disturbance, NO 3 Ϫ concentrations in streams increased during the following growing season and peaked during the second growing season in a consistent pattern (Fig. 1A). The magnitude of the streamwater response varied with the type and intensity of disturbance.The ice storm that struck New England in January 1998 was the most severe of the century (6) and as such provided a natural corollary to previous deforestation experiments. After the ice storm, there was extensive tree canopy damage (Ͼ50% loss) in a narrow elevation band (600-740 m in elevation) across the south-facing watersheds (7). The impact was estimated at 30% canopy loss for two well studied watersheds (watersheds 1 and 6) at Hubbard Brook Experimental Forest (HBEF) (7,8).This natural disturbance provided us with the unique opportunity to confirm several major paradigms of our long-term studies: (i) that forest disturbance leads to reduced watershed retention of nitrogen and increased export of NO 3 Ϫ in stream water (1, 2, 9-11); (ii) that solute pulses added to streams are rapidly attenuated (12-16); and (iii) that this attenuation is often the result of in-stream retention and processing, which are important regulators of nutrient export from watersheds (14,15,(17)(18)(19). MethodsSite Description. This research was done in two south-facing watersheds within the HBEF. Both watersheds 1 (W1) and 6 (W6) are small (11.8 and 13.2 hectares, respectively) and have not had any active land use change since forest harvesting ceased around 1920. The HBEF is located in north central New Hampshire (43°56ЈN, 71°45ЈW), and has a cool continental climate. Most of the basin is forested by American beech (Fagus grandifolia), sugar maple (Acer saccharum), and yellow birch (Betula allegheniensis). Both streams drain steep forest watersheds and have a characteristic stairstep sequence of waterfalls and pools with a substrate of cobbles and boulders. Ϫ , we multiplied the volume-weighted concentration by the total annual water yield from each site. Previous work at HBEF has demonstrated a strong relationship between watershed area and stream discharge in these watersheds, thus we calculated discharge and nutrient flux (discharge times nutrient concentration) at the damage-zone sampling site by multiplying discharge at the weir by the proportional watershed area of the subwatershed above the damag...

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Section: Resultsmentioning

confidence: 99%

In-stream uptake dampens effects of major forest disturbance on watershed nitrogen export

Bernhardt

Likens

Buso

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

154

134

View full text Add to dashboard Cite

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“…It is known that dissolved nutrients are removed primarily by sorption onto bottom sediments or active uptake by microbial communities attached to bottom substrata (19)(20)(21). Although the ammonium uptake per unit of area did not differ between forested and deforested reaches, the amount taken up per unit of channel length was significantly greater (often by 2-to 10-fold) in the forested reaches of most streams.…”

Section: Discussionmentioning

confidence: 88%

Riparian deforestation, stream narrowing, and loss of stream ecosystem services

Sweeney

Bott

Jackson

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

529

397

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A study of 16 streams in eastern North America shows that riparian deforestation causes channel narrowing, which reduces the total amount of stream habitat and ecosystem per unit channel length and compromises in-stream processing of pollutants. Wide forest reaches had more macroinvertebrates, total ecosystem processing of organic matter, and nitrogen uptake per unit channel length than contiguous narrow deforested reaches. Stream narrowing nullified any potential advantages of deforestation regarding abundance of fish, quality of dissolved organic matter, and pesticide degradation. These findings show that forested stream channels have a wider and more natural configuration, which significantly affects the total in-stream amount and activity of the ecosystem, including the processing of pollutants. The results reinforce both current policy of the United States that endorses riparian forest buffers as best management practice and federal and state programs that subsidize riparian reforestation for stream restoration and water quality. Not only do forest buffers prevent nonpoint source pollutants from entering small streams, they also enhance the in-stream processing of both nonpoint and point source pollutants, thereby reducing their impact on downstream rivers and estuaries.

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“…Besides a qualitative description of the infiltration process, the concentration of the conservative tracers (Br − and Cl − ) was used to calculate the proportion of different water sources (event vs. pre-event water) using a two-component end-member mixing (EMMA) model. The EMMA model has been widely used for hydrological studies to separate the different contributions of streamflow (Christophersen and Hooper, 1992;Mulholland and Hill, 1997;Soulsby et al, 2003;James and Roulet, 2006;Cras et al, 2007). The end members are usually defined from the reservoir characteristics; therefore mixing diagrams inform about the variable source areas of runoff.…”

Section: Analysis Methodsologymentioning

confidence: 99%

Field investigation of preferential fissure flow paths with hydrochemical analysis of small-scale sprinkling experiments

et al. 2014

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Abstract. The unsaturated zone largely controls groundwater recharge by buffering precipitation while at the same time providing preferential flow paths for infiltration. The importance of preferential flow on landslide hydrology is recognised in the literature; however, its monitoring and quantification remain difficult. This paper presents a combined hydrological and hydrochemical analysis of small-scale sprinkling experiments. It aims at showing the potential of such experiments for studying the spatial differences in dominant hydrological processes within a landslide. This methodology was tested in the highly heterogeneous black marls of the Super-Sauze landslide. The tests were performed in three areas characterised by different displacement rates, surface morphology and local hydrological conditions. Special attention was paid to testing the potential of small-scale sprinkling experiments for identifying and characterising preferential flow patterns and dominant hydrological processes.

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Seasonal patterns in streamwater nutrient and dissolved organic carbon concentrations: Separating catchment flow path and in‐stream effects

Cited by 253 publications

References 55 publications

In-stream uptake dampens effects of major forest disturbance on watershed nitrogen export

In-stream uptake dampens effects of major forest disturbance on watershed nitrogen export

Riparian deforestation, stream narrowing, and loss of stream ecosystem services

Field investigation of preferential fissure flow paths with hydrochemical analysis of small-scale sprinkling experiments

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