Nutrient concentrations and loads in the northeastern United States - Status and trends, 1975-2003

Trench, Elaine C. Todd; Moore, Richard B.; Ahearn, Elizabeth A.; Mullaney, John R.; Hickman, R. Edward; Schwarz, Gregory E.

doi:10.3133/sir20115114

Cited by 11 publications

(8 citation statements)

References 6 publications

(15 reference statements)

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“…In addition to the divergent mechanisms regulating DON and PON leaching, instream degradation and deposition of PON are also responsible for the different magnitudes of DON and PON fluxes. Nitrogen export in the study area as simulated by DLEM 2.0 is in line with previous estimates, which suggest that human activity have greatly increased nitrogen export to coastal waters [ Sprague and Lorenz , ; Trench et al ., ]. In particular, the increasing nitrogen export since the 1970s estimated by DLEM 2.0 agrees well with the analysis of Jaworski et al .…”

Section: Discussionmentioning

confidence: 99%

“…Field observations have provided reliable nitrogen export estimates [ Howden et al ., ; Raymond et al ., ]. For example, water quality data provided by the U.S. Geological Survey (USGS) gauge stations have made it possible to explore the spatial and temporal variability of riverine nitrogen fluxes in the U.S. [ Trench et al ., ]. However, application of this method is directly limited by the availability and integrity of field data.…”

Section: Introductionmentioning

confidence: 99%

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Increased nitrogen export from eastern North America to the Atlantic Ocean due to climatic and anthropogenic changes during 1901–2008

et al. 2015

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Nitrogen export demonstrated substantial spatial variability across the study area. Increased NH 4 + export mainly occurred around major cities in the MAB. NO 3 À export increased in most parts of the MAB but decreased in parts of the GOM. Enhanced DON export was mainly distributed in the GOM and the SAB. PON export increased in coastal areas of the SAB and northern parts of the GOM but decreased in the Piedmont areas and the eastern parts of the MAB. Climate was the primary reason for interannual variability in nitrogen export; fertilizer use and nitrogen deposition tended to enhance the export of all nitrogen species; livestock farming and sewage discharge were also responsible for the increases in NH 4 + and NO 3 À fluxes; and land cover change (especially reforestation of former agricultural land) reduced the export of the four nitrogen species.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Increased nitrogen export from eastern North America to the Atlantic Ocean due to climatic and anthropogenic changes during 1901–2008

et al. 2015

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“…Since 1992, NYC has been adding ortho-phosphoric acid to municipal drinking water to inhibit leaching of lead from old plumbing (Maas et al 2005), which likely contributed to increased DIP loadings into western LIS. Furthermore, some rivers throughout the northeastern US have also recently experienced rising P loadings, suggesting that LIS is being influenced by freshwater discharges (Trench et al 2012). DIP is also released during organic matter remineralization in anoxic sediments, explaining the negative relationship between bottom water DO and P concentrations (Kemp et al 2009).…”

Section: Trends In Lis Over 15 Yrmentioning

confidence: 99%

Phytoplankton assemblage changes during decadal decreases in nitrogen loadings to the urbanized Long Island Sound estuary, USA

Suter¹,

Lwiza²,

Rose³

et al. 2014

Mar. Ecol. Prog. Ser.

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Despite reductions in nitrogen loadings from wastewater treatment plants (WWTPs) discharging into Long Island Sound (LIS) over the last 15 yr, eutrophication and hypoxia remain a severe problem. Here we used time series of hydrography, meteorology, nutrients, and phytoplankton pigments to explore the relationships between planktonic biomass, nutrient stocks, and physical regimes in LIS. With the exception of the most eutrophied station in the west, dissolved inorganic nitrogen (DIN) decreased between 1995 and 2009, likely resulting from WWTP upgrades. However, total dissolved nitrogen increased during this period, primarily driven by rising organic nitrogen pools. Simultaneous increases in inorganic phosphorus, silicate, and chlorophyll a (chl a) were also observed. Starting in 2002, pigment-based phytoplankton community composition revealed systematic declines in diatom abundances coincident with increases in dinoflagellates and other flagellated phytoplankton groups. Despite this, bottom water dissolved oxygen concentrations did not improve. The apparent paradox between increasing DIN limitation and escalating chl a concentrations in LIS suggests a shifting nutrient stoichiometry and an altered phytoplankton community in which phytoflagellates have increased in abundance relative to diatoms. Despite these changes, diatoms remained the most abundant algal group by the end of the study. In addition, a shift in chl a stocks in the year 2000 coincided with decreases in temperature, increases in salinity, and the proliferation of several algal groups. These results reveal the complex nature of eutrophied estuaries and indicate that policies targeting only inorganic nitrogen loadings may be insufficient to mitigate eutrophication in systems such as LIS.

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“…The observed annual N load at Delaware River at Trenton is 14.2 million kg (31. We observed that nitrogen loads at USGS gages compare within 25-30% (±) of modeled loads from SPARROW [51]. The observed annual N load at Delaware River at Trenton is 14.2 million kg (31.2 million lb) compared to 11.4 million kg (25.1 million lb) from SPARROW.…”

Section: Resultsmentioning

confidence: 55%

“…Agriculture is the primary N source in the Delaware River at the Trenton (34%), Brandywine-Christina (77%), and Delaware Bay at Prime Hook (72%) watersheds and the second-highest N source in the Schuylkill watershed (35%). We observed that nitrogen loads at USGS gages compare within 25-30% (±) of modeled loads from SPARROW [51]. The observed annual N load at Delaware River at Trenton is 14.2 million kg (31.…”

Section: Resultsmentioning

confidence: 55%

The Cost of Clean Water in the Delaware River Basin (USA)

Kauffman

2018

Water

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Abstract:The Delaware River has made a marked recovery in the half-century since the adoption of the Delaware River Basin Commission (DRBC) Compact in 1961 and passage of the Federal Clean Water Act amendments during the 1970s. During the 1960s, the DRBC set a 3.5 mg/L dissolved oxygen criterion for the river based on an economic analysis that concluded that a waste load abatement program designed to meet fishable water quality goals would generate significant recreational and environmental benefits. Scientists with the Delaware Estuary Program have recently called for raising the 1960s dissolved oxygen criterion along the Delaware River from 3.5 mg/L to 5.0 mg/L to protect anadromous American shad and Atlantic sturgeon, and address the prospect of rising temperatures, sea levels, and salinity in the estuary. This research concludes, through a nitrogen marginal abatement cost (MAC) analysis, that it would be cost-effective to raise dissolved oxygen levels to meet a more stringent standard by prioritizing agricultural conservation and some wastewater treatment investments in the Delaware River watershed to remove 90% of the nitrogen load by 13.6 million kg N/year (30 million lb N/year) for just 35% ($160 million) of the $449 million total cost. The annual least cost to reduce nitrogen loads and raise dissolved oxygen levels to meet more stringent water quality standards in the Delaware River totals $45 million for atmospheric NOX reduction, $130 million for wastewater treatment, $132 million for agriculture conservation, and $141 million for urban stormwater retrofitting. This 21st century least cost analysis estimates that an annual investment of $50 million is needed to reduce pollutant loads in the Delaware River to raise dissolved oxygen levels to 4.0 mg/L, $150 million is needed for dissolved oxygen levels to reach 4.5 mg/L, and $449 million is needed for dissolved oxygen levels to reach 5.0 mg/L.

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Nutrient concentrations and loads in the northeastern United States - Status and trends, 1975-2003

Cited by 11 publications

References 6 publications

Increased nitrogen export from eastern North America to the Atlantic Ocean due to climatic and anthropogenic changes during 1901–2008

Increased nitrogen export from eastern North America to the Atlantic Ocean due to climatic and anthropogenic changes during 1901–2008

Phytoplankton assemblage changes during decadal decreases in nitrogen loadings to the urbanized Long Island Sound estuary, USA

The Cost of Clean Water in the Delaware River Basin (USA)

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