Effect of Nitrogen and Phosphorus Loading in Coastal Plain Blackwater Rivers

Malin, Michael A; Cahoon, Lawrence B.; Parsons, Douglas C.; Ensign, Scott H.

doi:10.1080/02705060.2001.9665832

Cited by 20 publications

(45 citation statements)

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“…3). Our results are generally consistent with previous studies (MALLIN et al, 2001; that showed N limitation of suspended algae in other lotic waters of this region. Industrialized animal production facilities employing spray field waste management practices are common in the watershed, and the low N : P ratio of the liquid waste may effect N limitation if fertilizer runoff enters surface waters (MALLIN et al, 2004).…”

Section: Discussionsupporting

confidence: 95%

Light‐Nutrient Influences on Biomass, Photosynthetic Potential and Composition of Suspended Algal Assemblages in the Middle Cape Fear River, USA

Dubbs

Whalen

2008

International Review of Hydrobiology

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Dilution bioassays were conducted to evaluate the impact of nutrients on biomass (chlorophyll a), photosynthetic potential, and class composition of suspended algal assemblages in the middle Cape Fear River (USA). Ambient concentrations of dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (SRP) varied from 37.2 to 83.8 and from 1.0 to 7.1 μmol L -1 . Experiments conducted at photosynthetic photon flux densities (PPFDs) similar to the mixed water column (< 1 to 5.3 E m -2 d -1 ) showed no change in chlorophyll a, photosynthetic potential, or algal class composition at 15, 30, and 45% dilutions of DIN, SRP, or both. However, chlorophyll a and photosynthetic potential increased significantly in nutrient dilution bioassays conducted at PPFDs four-fold above ambient, while the abundance of diatoms and Chrysophytes increased under elevated PPFD and ambient or elevated nutrients. Overall, the data indicate that irradiance is more important than nutrients in determining the size and class composition of suspended algal assemblages. IntroductionNutrient enrichment is a serious water quality problem in coastal and estuarine waters worldwide (NIXON, 1995;SMITH, 1998;CLOERN, 2001;PAERL et al., 2003). North Carolina (NC) estuaries are no exception, showing a contemporary propensity for bottom water hypoxia and anoxia, fish kills, and development of algal blooms (toxic and otherwise), which are all evidence of declining water quality (BURKHOLDER et al., 1997;PAERL et al., 1998;MALLIN et al., 2000). Recent attention in NC has focused on the Cape Fear River (CFR) Estuary, which is regarded as moderately eutrophic (BRICKER et al., 1999). The upper estuary and parts of the inflowing CFR are considered impaired relative to designated uses due to low dissolved oxygen or high chlorophyll a (chl a) concentrations (NCDENR, 2005). MAL- LIN et al. (2006) interpreted a strong correlation between biochemical oxygen demand (BOD) and chl a, and the lack of correlation between BOD and total N or total P at a mesohaline station on the lower CFR, to indicate that decomposition of suspended algae delivered from upriver was responsible for high BOD at this site.

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Section: Discussionsupporting

confidence: 95%

Light‐Nutrient Influences on Biomass, Photosynthetic Potential and Composition of Suspended Algal Assemblages in the Middle Cape Fear River, USA

Dubbs

Whalen

2008

International Review of Hydrobiology

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“…Treatments included addition of: 20 lmol l -1 NH 4 + -N (N); 4 lmol l -1 PO 3À 4 P (P); or 20 lmol l -1 NH 4 + -N plus 4 lmol l -1 PO 3À 4 P (N+P). Results from day 3 of each 3 days experiments are shown a Disintegrations per minute Phytoplankton chlorophyll a and primary production Average phytoplankton chl a concentrations of 6.4-10.8 lg l -1 for the middle CFR (Table 2) are a factor of 2-10 higher than values of 0.7-3.9 lg l -1 given for higher order ( ‡4) blackwater rivers in the southeastern US (Bledsoe & Phlips, 2000;Mallin et al, 2001Mallin et al, , 2006. However, our phytoplankton chl a values are generally lower than regional data for tidally influenced freshwater or oligohaline stations in coastal rivers less impacted by dissolved organic inputs from bottomlands.…”

Section: Physicochemicalmentioning

confidence: 97%

“…Mallin et al (2001Mallin et al ( , 2004 and give mean NO 3 --N, NH 4 + -N and SRP concentrations varying from 0.5 to 37 lmol l -1 , 2.4 to 6.5 lmol l -1 and 0.3 to 1.4 lmol l -1 for six rivers ranging from third to fifth order in the NC coastal plain, while Edwards & Meyer (1987) reported that NO 3 --N, NH 4 + -N and SRP concentrations varied from 2.1 to 22.9 lmol l -1 , 0.7 to 3.6 lmol l -1 and 0.6 to 2.6 lmol l -1 for the sixth order Ogeechee River, GA. Highest concentrations of DIN and SRP in the sixth order St. John's River (FL) appear to be about 28 lmol l -1 and 4.5 lmol l -1 from data given in Phlips et al (2000), while Whalen & Benson (2007) report concentrations of NO 3 --N, NH 4 + -N and SRP varying from 14 to 59 lmol l -1 , 0.6 to 4.8 lmol l -1 and 0.4 to 1.3 lmol l -1 for a site above tidewater on the lower Neuse River, NC.…”

Section: Physicochemicalmentioning

confidence: 97%

Seasonality and controls of phytoplankton productivity in the middle Cape Fear River, USA

Kennedy

Whalen

2007

Hydrobiologia

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Our 1 year study was aimed at assessing seasonal patterns and controls on phytoplankton primary production (PPR) and biomass (chlorophyll a) in a fourth order section of the middle Cape Fear River in North Carolina, USA, and to determine the impact of three low-head lock and dam (LD) structures on these variables within the 70 km study reach of this coastal river. Mean concentrations of NO 3 --N, NH 4 + -N and soluble reactive phosphorus (SRP) averaged 52.9, 6.0, and 3.6 lmol l -1 in monthly sampling, while the average light attenuation coefficient was 2.4 m -1 . The average euphotic depth was 2.1 m. Nutrient concentrations and attenuation coefficients were not significantly different above versus below each LD, or along the entire study reach. Significantly higher concentrations of dissolved O 2 below versus above each LD were attributed to re-aeration during spillway transit. No seasonal pattern in physicochemical properties was apparent. Phytoplankton chlorophyll a concentrations ranged from \1 to 36 lg l -1 , while rates of primary production ranged from 18 to 2,580 mg C m -2 day -1 , with values for both variables peaking in the spring and early summer. Chlorophyll a and primary productivity values were consistently higher above versus below each LD in May and June suggesting a seasonal effect, but values were otherwise similar such that overall means were not significantly different. Several factors point to light as the primary control on phytoplankton in the middle Cape Fear River: high nutrient concentrations; a low ratio of euphotic : mixing depth (0.46); progressive increases in chlorophyll a and radiocarbon uptake in all treatments in quarterly nutrient enrichment bioassays conducted at levels of irradiance elevated relative to in situ river values; and consistently low quarterly values of P B m (maximum rate of chlorophyll-normalized C uptake; £3.7 mg C mg chl a -1 h -1 ) and I k (light saturation parameter; £104 lmol photons m -2 s -1 ) for photosynthetic light-response (P-I) curves.

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“…This river exhibits the typical blackwater characteristics (Mallin et al, 2001) and occupies approximately 438,522 ha (1,693 square miles) of the LCFR watershed (Fig. 1).…”

Section: Study Sitesmentioning

confidence: 99%

“…Sources of low DO levels include natural and anthropogenic sources of oxygen consuming nutrients from the upstream blackwater rivers, such as: LCFR, Black River and Northeast Cape Fear River (NECFR). Several studies indicate that N and P addition to blackwater rivers due to land uses support algal blooms during selected period and stimulated growth of heterotrophic macroflora, which becomes source of labile biochemical oxygen demand and oxygen deficit (Mallin et al, 2001;Seitzinger et al, 2002). As a follow up to these studies, a watershed model based assessment was conducted to determine N and P loads entering the LCFR from a large blackwater river under different land use scenarios, including large-scale agricultural operations, intensive swine operations and conventional point-source discharges.…”

Section: Introductionmentioning

confidence: 99%

Identifying Nutrient Contributors in North Carolina’s Coastal Plain Blackwater Rivers

Rajbhandari¹,

Pradhan²,

Luzio³

et al. 2015

American Journal of Environmental Sciences

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Abstract:The goal of this study was to assess potential nitrogen and phosphorus contribution from point sources and non-point sources in North East Cape Fear River (NECFR) watershed in North Carolina. A watershed scale hydrologic model, Soil and Water Assessment Tool (SWAT), was used to quantify Total Nitrogen (TN) and Total Phosphorus (TP) loadings to North Carolina's Coastal Plain Blackwater Rivers. The model was calibrated to measured flow rate, TN, TP and suspended sediment concentrations. The model results suggest that nonpoint sources contribute more than 95% of the nutrient loads from the NECFR to the Lower Cape Fear River (LCFR), where low dissolved oxygen is a prime concern. Among the nonpoint sources, developed open space, forested wetland and agricultural land were responsible for approximately 20 to 35% of the total annual sediment loads (68838.60 tons) and the Total Phosphorus (TP) loads (452.20 tons) delivered to the LCFR. In addition forested wetlands, agricultural lands and forested lands contributed approximately 20 to 33% of the TN loads (3496.79 tons) to the river. While the forested wetlands assimilated more than 70% of the nutrient inputs, they also acted as sources of nutrients in the watershed. The results demonstrate that these wetlands were not substantially capable of trapping nutrient loading coming from adjoining lands for a longer period. Owing to the presence of more ditches, these wetlands functioned as a passive nutrient source by transporting significant amount of TN and TP into the river. However, these findings need to be further justified by conducting a field study to understand assimilative capacity of wetlands in the watershed.

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Effect of Nitrogen and Phosphorus Loading in Coastal Plain Blackwater Rivers

Cited by 20 publications

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Light‐Nutrient Influences on Biomass, Photosynthetic Potential and Composition of Suspended Algal Assemblages in the Middle Cape Fear River, USA

Light‐Nutrient Influences on Biomass, Photosynthetic Potential and Composition of Suspended Algal Assemblages in the Middle Cape Fear River, USA

Seasonality and controls of phytoplankton productivity in the middle Cape Fear River, USA

Identifying Nutrient Contributors in North Carolina’s Coastal Plain Blackwater Rivers

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Effect of Nitrogen and Phosphorus Loading in Coastal Plain Blackwater Rivers

Cited by 20 publications

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Light‐Nutrient Influences on Biomass, Photosynthetic Potential and Composition of Suspended Algal Assemblages in the Middle Cape Fear River, USA

Light‐Nutrient Influences on Biomass, Photosynthetic Potential and Composition of Suspended Algal Assemblages in the Middle Cape Fear River, USA

Seasonality and controls of phytoplankton productivity in the middle Cape Fear River, USA

Identifying Nutrient Contributors in North Carolina&rsquo;s Coastal Plain Blackwater Rivers

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Identifying Nutrient Contributors in North Carolina’s Coastal Plain Blackwater Rivers