Effects Of Nitrogen Loading Research Articles

Effect of nitrogen loading on denitrification, denitritation and filtration performances of membrane bioreactors fed with biogenic and chemical elemental sulfur

Autotrophic denitrification with elemental sulfur (S0) as an electron donor is a clean and cost-effective solution for nitrogen removal from contaminated waters poor in organics and has gained increasing interest in the last decades. In contrast, less attention has been driven towards autotrophic denitritation and the effect of nitrogen oxide (N-NOx−) loading and feeding strategy on the process. This study investigates the denitrification and denitritation performances of two membrane bioreactors fed with chemically synthesized S0 (S0chem) and biogenic S0 (S0bio) under different N-NOx− loading rates (50 and 100 mg N-NOx− L−1 d−1) and feeding strategies (nitrate or nitrite only and both nitrate and nitrite) and their influence on the specific nitrogen uptake rate (SNUR) of S0-oxidizing denitrifiers. N-NOx− removal was faster with S0bio compared to S0chem at all tested N-NOx− loading rates and feeding strategies, confirming S0bio as an advantageous electron donor for autotrophic NO3− and NO2− reductions. Influent NO2− levels as high as 100 mg N-NO2− L−1 did not inhibit autotrophic denitrification and denitritation. On the contrary, batch activity tests showed that NO2− feeding resulted in higher SNUR values compared to feeding with both NO3− and NO2− and with NO3− only, confirming NO2− as a more thermodynamically favorable electron acceptor than NO3−. The impact of different operational conditions on membrane filtration performance was also evaluated, showing that S0bio was the main responsible for pressure increase and membrane fouling during bioreactor operation.

Effect of nitrogen loading on the nitrogen removal performance in membrane bioreactor coupled with elemental sulfur-based carriers

Effect of nitrogen loading on the nitrogen removal performance in membrane bioreactor coupled with elemental sulfur-based carriers

Effects of nitrogen loading from domestic wastewater on groundwater quality

In this study the effects of nitrogen effluent from a permeable constructed sewage tank on groundwater quality were investigated. Sampling took place before and 1.5 years after the closure. Using a 3D hydrogeological model, the spatial distribution of dissolved inorganic nitrogen (DIN), comprising the species NH4+, NO2- and NO3-, was modelled in the saturated zone and the amounts and changes in the ratio of NH4-N, NO2-N, NO3-N were determined. The first part of our general hypothesis, that the groundwater was heavily contaminated in the area surrounding the sewage tank, was clearly verified, since every investigated nitrogen compound exceeded the contamination limit values; but the second part of our hypothesis, that the degree of contamination would significantly decrease after the sewage tank was taken out of use has not been confirmed, since the amount of nitrogen present in inorganic forms increased in the modelled zone. The increase in DIN and the relatively high concentration of NH4+ (35 mg/L) in the immediate vicinity of the tank can be explained by the fact that organic matter (OM) accumulated over the decades provided a constant supply of inorganic nitrogen forms.

Effects of nitrogen loading on emission of carbon gases from estuarine tidal marshes with varying salinity

Estuarine tidal marshes sequester significant quantities of carbon and are suffering from anthropogenic nitrogen (N) enhancement. However, the effects of this N loading on carbon gas emissions from freshwater-oligohaline tidal marshes are unknown. In this paper, we report on our evaluation of the effects of a N gradient (0, 24, 48 and 96 g NH4NO3–N m−2 y−1) on the methane (CH4) and carbon dioxide (CO2) emissions from freshwater and oligohaline tidal marshes in the Min River estuary, southeast China. On an annual scale, the oligohaline marsh has significantly higher CO2 emissions, while it has slightly lower CH4 emissions relative to freshwater marsh. The addition of N increased CH4 emission from the freshwater marsh and decreased CH4 emission from the oligohaline marsh, although there was no statistically significant difference in CH4 emission between either of the two marshes and the control. The addition of 96 g NH4NO3–N m−2 y−1 significantly increased CO2 emission from the freshwater marsh, while it did not significantly influence CO2 emission from the oligohaline marsh. CH4 and CO2 emission levels were positively correlated with soil temperature under all conditions. The CH4 flux resulting from both the control and the addition of N was negatively correlated with porewater SO42− and Cl− concentrations and soil EC in the oligohaline marsh. Overall, N addition significantly increased carbon gas emissions under freshwater conditions while slightly inhibiting carbon gas emissions from the oligohaline marsh. Our findings suggested that even under low salinity conditions, the effects of N loading on CH4 and CO2 emissions from freshwater and oligohaline tidal marshes can vary. We propose that the addition of N to estuarine tidal marshes has a significant effect on the carbon cycle and promotes soil carbon loss, phenomena which may be influenced by salinity.

Effects of nitrogen loading under low and high phosphorus conditions on above- and below-ground growth of hybrid larch F1 seedlings

Under present environmental conditions, hybrid larch F1 (Larix gmelinii var. japonica × Larix kaempferi) is a promising afforestation species as it has a high growth rate and tolerance against grazing damage, disease and cold. However, the input of nitrogen (N) to forests due to the increase of anthropogenic N is causing imbalances of N compared to other nutrients, especially phosphorus (P), thus affecting the root growth of healthy seedlings. However, knowledge on how different N and P conditions affect F1 root growth is still limited. In this study, various N (3 levels) and P (no addition and addition) conditions were imposed to investigate the effect of N loading on larch F1 seedlings under different P conditions. Needle N: P ratio, aboveground growth, belowground growth as well as fine root production were measured. The results showed that needle N: P ratio was higher under low P loading, and aboveground growth of seedlings increased with N loading at both low and high P conditions. Relative fine root production was decreased by N loading. On the other hand, fine root to total dry proportion was increased by N loading at no P addition, suggesting that limited P availability could increase fine root production. Total root proportion to total dry mass was decreased by N loading at both P conditions. We concluded that N loading has different effects on above- and below-ground growth of larch F1 and its effects may also differ according to P conditions, indicating that both N and P conditions should be carefully considered when planting hybrid larch F1.

Effect of nitrogen loading on the growth and photosynthetic responses of Japanese larch seedlings grown under different light regimes

Effect of nitrogen loading on the growth and photosynthetic responses of Japanese larch seedlings grown under different light regimes

Eutrophication has no short-term effect on the Cymbastela stipitata holobiont.

Levels of nitrogen in coastal areas have been rapidly increasing due to accumulative inputs of sewage and terrigenous sediments carrying fertilizers. Sponges have an immense filtering capacity and may be directly impacted (positively or negatively) by elevated concentrations of nitrogen. Sponges also host a wide diversity of microbes involved in nitrogen metabolism, yet little is known about the effects of nitrogen loading on these symbiotic partnerships. Manipulative experiments were undertaken to examine the potential effects of excess nitrogen (up to 240 μM) on microbial symbiosis in the abundant sponge species Cymbastela stipitata. Microbial composition and activity were examined using 454-pyrotag sequencing of DNA- and RNA-derived samples. Despite the high levels of nitrogen exposure (up to 124-fold above ambient), sponges appeared visibly unaffected at all treatment concentrations. At the phylum level, the microbial community was consistent between all sponge samples regardless of nitrogen treatment, with Cyanobacteria and Thaumarchaeota being the dominant taxa. Higher microbial diversity was observed at the operational taxonomic units (OTU) level (97% sequence similarity), with only 40% of OTUs shared between samples from all treatments. However, a single cyanobacterial OTU dominated the community of all individuals (average 73.5%) and this OTU did not vary with nitrogen treatment. The conserved microbial community in all sponges irrespective of nitrogen treatment highlights the stability of the sponge-microbe relationship and indicates that the holobiont is resistant to short pulses of nitrogen at levels mimicking sewage effluent.

Effects of Nitrogen Load on the Function and Diversity of Methanotrophs in the Littoral Wetland of a Boreal Lake

Methane is the second most abundant greenhouse gas in the atmosphere. A major part of the total methane emissions from lake ecosystems is emitted from littoral wetlands. Methane emissions are significantly reduced by methanotrophs, as they use methane as their sole energy and carbon source. Methanotrophic activity can be either activated or inhibited by nitrogen. However, the effects of nitrogen on methanotrophs in littoral wetlands are unknown. Here we report how nitrogen loading in situ affected the function and diversity of methanotrophs in a boreal littoral wetland. Methanotrophic community composition and functional diversity were analyzed with a particulate methane monooxygenase (pmoA) gene targeted microarray. Nitrogen load had no effects on methane oxidation potential and methane fluxes. Nitrogen load activated pmoA gene transcription of type I (Methylobacter, Methylomonas, and LW21-freshwater phylotypes) methanotrophs, but decreased the relative abundance of type II (Methylocystis, Methylosinus trichosporium, and Methylosinus phylotypes) methanotrophs. Hence, the overall activity of a methanotroph community in littoral wetlands is not affected by nitrogen leached from the catchment area.

Relationships between Nutrient Enrichment and Benthic Function: Local Effects and Spatial Patterns

Eutrophication-induced changes to benthic faunal activities are problems of significant ecological impact, affecting global nutrient budgets as well as local trophic connections. We address the question of how nitrogen loads to estuarine embayments alter the bioturbation activities of benthic fauna. Specifically, we related local benthic activities to calculated local nitrogen concentrations for 22 northeastern US estuaries. These local nitrogen concentrations were derived from the calculated nitrogen loading for the embayment together with the spatial distribution of the local flushing time. Our results showed a maximum bioturbation rate at intermediate nitrogen concentrations or a “hump-shaped” pattern of response. This behavior was evident in all embayments that had a range of concentrations including low, intermediate, and high values. Embayments where sampling did not include this full range did not show this behavior. This work provides methods and guidance to help managers make decisions concerning the effects of nitrogen loading on the activities and well-being of benthic fauna in coastal embayments. The novelty of this approach lies in identifying the response of bioturbation to nitrogen loading in many systems, without costly and time-consuming speciation of benthic fauna, and also in rapidly identifying embayments and aquatic areas with vulnerable fauna. These results are ecologically significant in supporting the hypothesis that benthic organism abundance and activity will peak at mid-levels of nitrogen due to the interplay of food availability and oxygen levels, noting that the critical levels of these factors differ among water bodies.

The effect of nitrogen loading on on-site system design: a model for determining land application area size

Designers of on-site wastewater management systems have six opportunities to remove pollutants of concern from the aqueous waste stream before it reaches ground or surface waters. These opportunities occur at source, at point of collection (primary treatment), secondary treatment, tertiary treatment, land application and buffers. This paper presents a computer based model for the sizing of on-site system land application areas applicable to the Lismore area in Northern New South Wales, a region of high rainfall. Inputs to the model include daily climatic data, soil type, number of people loading the system and size of housing allotment. Constraints include allowable phosphorus export, nitrogen export and hydraulic percolation. In the Lismore area nitrogen is the nutrient of most concern. In areas close to environmentally sensitive waterways, and in dense developments, the allowable annual nitrogen export becomes the main factor determining the land application area size. The model offers system designers the opportunity to test various combinations of nitrogen attenuation strategies (source control, secondary treatment) in order to create a solution which offers an acceptable nitrogen export rate while meeting the client's household and financial needs. The model runs on an Excel spreadsheet and has been developed by Lismore City Council.

Denitrification in bottom sediment near oil production facilities off the Louisiana Gulf Coast

There is little information on denitrification in Gulf of Mexico bottom sediment. Potential denitrification rates in surface sediment were measured along transects legs extending 0–800 m from two offshore oil production platforms. The average potential denitrification ranged from approximately 50 mg N m−2 d−1 in surface sediment near the platforms to 15 mg N m−2 d−1 in sediment 800 m from the platforms. Measured denitrification rates were correlated to a higher organic matter content in sediment nearer the platforms. This research examined only a small component of nitrogen processing in Gulf of Mexico sediment. Additional research should examine the effect of nitrogen loading and temporal and spatial variability on denitrification rate.

Effects of Nitrogen Load on Growth and Leaf Nutrient Status of Japanese Evergreen Broad-leaved Tree Species

Effects of Nitrogen Load on Growth and Leaf Nutrient Status of Japanese Evergreen Broad-leaved Tree Species

The effect of nitrogen loading on a brackish estuarine faunal community: A stable isotope approach

Coastal ecosystems worldwide face increased nutrient enrichment from shoreline and watershed development and atmospheric pollution. We investigated the response of the faunal community of a small microtidal estuary dominated byRuppia maritima (widgeon grass) in Maine, United States, to increased nitrogen loading using an in situ mesocosm enrichment experiment. Community response was characterized by assessing quantitative shifts in macroinvertebrate community composition and identifying changes in food web structure using stable carbon and nitrogen isotope ratios of producers and consumers. The community was dominated by brackish water invertebrates including midge larvae, oligochaetes, damselfly larvae, amphipods, and ostracods. Experimental nutrient additions resulted in significantly lower densities of herbivorous chironomids and predatory damselflies and greater densities of deposit feeding oligochaetes. Grazing midge larvae (Chironomidae:Dicrotendipes, Cricotopus) consumed epiphytic algae under both natural and enriched conditions. Deposit feedingChironomus was dependent on allochthonous sources of detritus under natural conditions and exhibited a shift to autochthonous sources of detritus under enriched conditions. PredatoryEnallagma primarily consumed grazing chironomids under all but the highest loading conditions. Experimental nutrient loading resulted in an increase in generalist deposit feeders dependent on autochthonous sources of detritus.

The effect of nitrogen loading on the growth rates of quahogs ( Mercenaria mercenaria) and soft-shell clams ( Mya arenaria) through changes in food supply

Development of coastal areas in Cape Cod has increased nitrogen (N) loading to the region's estuaries. Nitrogen supply limits phytoplankton, the major food source of many filter-feeding bivalves living in the estuaries, including quahogs ( Mercenaria mercenaria) and soft-shell clams ( Mya arenaria). N enrichment may therefore affect growth rates of these shellfish by altering their food supply in the water column. In this study, food quantity, as measured by chlorophyll a as a proxy for phytoplankton, was found to be higher in estuaries subject to higher N load. The food quality in these estuaries, measured by the ratio of C to N, remained constant. Results of growth rate experiments on quahogs and soft-shell clams planted in three estuaries of different N load revealed that the shellfish grew fastest in estuaries where phytoplankton abundance was highest. Nitrogen stable isotope analysis confirmed that shellfish were consuming food from within their own estuaries, rather than food from an outside source. Therefore, it appears N load affected the growth rates of the shellfish primarily through causing changes in the quantity, rather than the quality, of the food supply.

Effects of nitrogen load and irradiance on photosynthetic pigment concentrations in Cladophora vagabunda and Gracilaria tikvahiae in estuaries of Waquoit Bay.

If coastal zone managers wish to regulate septic nitrogen loads, they could concentrate on management of septic systems that lie within 480-730 m of the shore, since these appeared to be the major contributors of nitrate to receiving estuaries. Septic sources farther upgradient probably contribute less significantly. This research was supported by an internship from the Woods Hole Marine Science Consortium to Elizabeth Westgate, an MIT Sea Grant (#65591) awarded to Ivan Valiela and Harold Hemond, and National Estuarine Research Reserve Fellowships to Kevin Kroeger and Wendy Pabich.

Effect of Nitrogen Loading on Enzyme Activity of Macroalgae in Estuaries in Waquoit Bay

Effect of Nitrogen Loading on Enzyme Activity of Macroalgae in Estuaries in Waquoit Bay

Effects of Nitrogen Loading on Eelgrass Seed Coat Abundance, C to N Ratios, and δ15N in Sediments of Waquoit Bay.

Previous articleNext article No AccessECOLOGYEffects of Nitrogen Loading on Eelgrass Seed Coat Abundance, C to N Ratios, and δ15N in Sediments of Waquoit BayR. E. Safran, J. C. Legra, and I. ValielaR. E. Safran Search for more articles by this author , J. C. Legra Search for more articles by this author , and I. Valiela Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 195, Number 2October 1998 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.2307/1542862 Views: 6Total views on this site Citations: 1Citations are reported from Crossref Copyright © 1998 by Marine Biological LaboratoryPDF download Crossref reports the following articles citing this article:J. C. Legra, R. E. Safran, and I. Valiela Lead Concentration as an Indicator of Contamination History in Estuarine Sediments, The Biological Bulletin 195, no.22 (Sep 2016): 243–244.https://doi.org/10.2307/1542861

Shrimp in Waquoit Bay: Effects of Nitrogen Loading on Size and Abundance.

Previous articleNext article No AccessECOLOGYShrimp in Waquoit Bay: Effects of Nitrogen Loading on Size and AbundanceC. Fritz, E. LaBrecque, J. Tober, P. J. Behr, and I. ValielaC. Fritz Search for more articles by this author , E. LaBrecque Search for more articles by this author , J. Tober Search for more articles by this author , P. J. Behr Search for more articles by this author , and I. Valiela Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 191, Number 2October 1996 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/BBLv191n2p326 Views: 15Total views on this site Citations: 2Citations are reported from Crossref Copyright © 1996 by Marine Biological LaboratoryPDF download Crossref reports the following articles citing this article:Melissa Millman, Mirta Teichberg, Paulina Martinetto, and Ivan Valiela Response of Shrimp Populations to Land-Derived Nitrogen in Waquoit Bay, Massachusetts, The Biological Bulletin 203, no.22 (Sep 2016): 263–264.https://doi.org/10.2307/1543432A. Whitman, J. Tober, and I. Valiela Growth Rates and Abundance of Fundulus heteroclitus in Estuaries Subject to Different Land-Derived Nitrogen Loads in Waquoit Bay, Massachusetts, The Biological Bulletin 193, no.22 (Sep 2016): 289–290.https://doi.org/10.1086/BBLv193n2p289

Effects of Nitrogen Loading and Salt Marsh Habitat on Gross Primary Production and Chlorophyll a in Estuaries of Waquoit Bay.

Nixon (1) showed, using comparative data from different systems, that increased nitrogen load to shallow coastal estuaries increased production of phytoplankton. Furthermore, it has been well established that the growth of coastal producers is nitrogen limited (2). In Waquoit Bay, we have a complex of separate estuaries that are subject to different nitrogen loading rates (3). This variation in loading rate provides the opportunity to test, in one system, whether increased nitrogen loads result in increased production. The range of nitrogen loading to the estuaries extended from a high rate of 8.1 X 1 O3 kg N y-’ in Childs River to approximately 0.05 1 kg N y-’ in Sage Lot Pond. Because phytoplankton growth in shallow estuaries is nitrogen limited (2), increased loading rates are likely to affect activity and abundance of these primary producers. Salt marsh habitats are active sites of denitrification and nutrient uptake (2). A strip of salt marsh located between the watershed and the estuary could, therefore, intercept incoming nitrogen and significantly reduce estuarine nitrogen loading. The estuaries of Waquoit Bay are surrounded by different areas of salt marsh. We could, consequently, also evaluate the effects of salt marsh on interception of nitrogen by comparing phytoplankton abundance and activity in estuaries with different extents of fringing salt marsh. In this paper we ask, first, whether there is a relationship between nitrogen loading rate and phytoplankton abundance and productivity; and second, whether the presence of a salt marsh fringe decreases the nitrogen loading rate and, accordingly, lowers phytoplankton abundance and productivity. We measured gross primary production (GPP) and chlorophyll a concentration at two stations in each of five estuaries of Waquoit Bay (Childs River, Quashnet River, Jehu Pond, Hamblin Pond, and Sage Lot Pond). We used standard light/dark bottle technique with 5-h in situ incubation period, and the Winkler titration method to determine primary production of the estuaries. Chlorophyll a concentration was measured by the Lorenzen method (4). The nitrogen loading rate was calibrated based on total dissolved nitrogen (DIN) at shore edge, rate of water recharge, and total area of the estuary. GPP and chlorophyll a increased significantly with higher nitrogen loads (Fig. 1, top panels). For the regression of phytoplankton and loading, P < 0.003 for both GPP and Chl a. In Childs River, for example, the average chlorophyll a concentration and GPP levels were about three times as high as those in Sage Lot Pond. Both GPP rates and chlorophyll a concentration decreased in estuaries with larger areas of fringing salt marsh (Fig. 1, middle panels). The cause of this decrease is not well established. The salt marshes could be physically removing phytoplankton from the flooding estuarine water during high tide and, thus, lowering

Effect of Nitrogen Load and Water Temperature on Treatment Efficiency of Anoxic Reactor Using Submerged Bed Process.

The effects of nitrogen load and water temperature on the treatment efficiency were studied using an anoxic rector equipped with a lace-like contact media. Experiments were conducted under various nitratenitrogen (NO3-N) loads and water temperatures. Temperature coefficients (θ) of 1.046-1.064 were calculated. An equation expressing the relationship between NOx-N removal efficiency, the NOx-N load and water temperature was obtained. From the equation, the NOx-N load that allows a high NOx-N removal efficiency in the anoxic reactor can be estimated, and the value was greatly effected by water temperature. Denitrification rates of 2.4-4.5 mg-N/g-SS·hr under water temperature of 30°C were obtained.