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Paper 223 FA FYT EA BBE RAF Institution of Engineers, Malaysia, 84(1) 2023 22-30
Abstract
Ammonium is a form of nitrogen that can be present in natural water systems due to various sources, including agricultural runoff, wastewater discharge, and decomposition of organic matter. High concentrations of ammonium in seawater can have several significant consequences for marine ecosystems such as harmful algal blooms, oxygen depletion, acidification, and changes in nutrient ratios. Therefore, monitoring and regulating nutrient inputs are essential for protecting marine ecosystems and maintaining the health and productivity of coastal and open ocean environments. In this study, adsorption isotherm experiments were used to study ammonium adsorption by surface bed sediments in the Loughor Estuary, South Wales, UK. The findings indicated that the adsorption isotherm was linear and fitted the Freundlich adsorption isotherm. The adsorption coefficient of ammonium in the study area ranged from 9.3 to 18 ml/g and the dimensionless ammonium adsorption coefficient was found to be ranged between 23.0 and 36.5. These values correlated well with the organic carbon content, of the sediments and can be considered as the main factors controlling ammonium sorption. The results also showed that salinity affected the adsorption of ammonium and the distribution of ammonium between the sediments and the water column. The amount of ammonium adsorption on the sediments was found to decrease gradually with the increment of the salinity levels.
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BACKGROUND
Nitrogen (N) is the most limiting nutrient in rice production. N loss via denitrification and ammonia (NH3) volatilization decreases N utilization efficiency. The effect of periphyton (a widespread soil surface microbial aggregate in paddy soil) on N‐cycling processes and rice growth in paddy soils remain unclear. The purpose of this study was to reveal the interactions of periphyton with the overlying water and sediment in paddy soils on denitrification/NH3 emissions and rice yield by combining pot experiments and path analysis modeling.
RESULTS
The sediment exerted significant direct and positive effects on denitrification. The periphyton both directly and indirectly enhanced denitrification, mainly by regulating the ammonium (NH4⁺)‐N content in the sediment. The total contribution of periphyton to denitrification was stronger than that of the overlying water but smaller than that of the sediment. The pH in the overlying water and the NH4⁺‐N content in the sediment had a strong positive effect on NH3 volatilization. Although the periphyton biomass and chlorophyll a directly prohibited NH3 emissions, this was counterbalanced by the indirect stimulation effects of the periphyton due to its positive alteration of the pH. Moreover, periphyton facilitated rice yield by 10.2% by releasing N.
CONCLUSION
Although the periphyton may have driven N loss by regulating the NH4⁺‐N content in the sediment and the pH in the overlying water, our study also found that the periphyton was considered a temporary N sink and provided a sustained release of N for rice, thus increasing the rice yield. © 2022 Society of Chemical Industry.
The Holocene muddy infill of the valley incised by the ancient Red River during Pleistocene sea-level lowstand records a change from fluvial to estuarine and finally marine depositional conditions. Siphonichnus, a mainly vertical trace fossil produced by burrowing bivalves, documents otherwise unrecorded episodes of enhanced erosion, bypass and deposition of, on average, rapidly aggrading (> 1 m kyr −1), mainly completely bioturbated sediments within the fluvial-marine transition zone (FMTZ), supposedly within the polyhaline domain. The producers of Siphonichnus moved nearly 1 m downward or upward in response to erosional or depositional phases, respectively. The fill of Siphonichnus burrows, in addition, records erosion and/or bypass of sediment: The traces were produced in mud, but many of them are filled with coarse silt and sand that is otherwise not present in the studied intervals in distinct layers. Obviously, this material was available when Siphonichnus was produced and connected to the sediment surface. In addition to seasonal erosion and deposition during freshet and its waning stage, Siphonichnus records exceptional events that displace the sediment surface by > 0.5 m. Such events occurred episodically at an estimated frequency of 1 event per several hundreds of years. The complete bioturbation of the deposits suggests apparent continuous accumulation, but in fact they represent a pile of stacked event deposits resulting from depositional phases and intermittent severe erosion.
Nitrogen enters rivers and coastal regions through runoff, atmospheric deposition and precipitation. This leads to increasing nitrogen input to the water body and subsequently to eutrophication problems. The ammonium ion is a major component of nitrogen loading to coastal areas and since nitrogen is the limiting nutrient in many coastal marine waters, sediments are a major site controlling the cycling and availability of nitrogen. Ammonium can diffuse to overlying water and be adsorbed onto the sediment.
The purpose of this experimental study was to find the adsorption coefficient and the adsorption isotherm of the ammonium ion for clay (Kaolinite and Montmorillonite) and sand (coarse and fine grades) using distilled and artificial sea water. This study showed that the ammonium adsorption for all four sediment types investigated was almost linear and fitted to the Freundlich isotherm within different concentrations in both distilled and artificial sea water. The adsorption in Montmorillonite, Kaolinite and coarse and fine sand in distilled water was higher than the amount of ammonium ions adsorbed in artificial sea water. The adsorption coefficient was higher under distilled water and lower under artificial sea water.
The process and controls of ammonium adsorption in marine sediments have been studied using data from adsorption experiments with sediments from Saanich Inlet, British Columbia, and with standard reference clays. The average NH 4 ⁺ adsorption constant determined experimentally for a Saanich Inlet core of 5.3 ± 1.8 liters·mol ⁻¹ was not significantly different from the constant measured in situ of 6.1 liters·mol ⁻¹ .
Equations similar to a Langmuir‐type isotherm are derived which express ammonium adsorption in terms of equilibrium exchange expressions (selectivity coefficients) and activities of the major cations. An ammonium adsorption constant calculated from the model for a montmorillonite clay of 12.6 ± 1.7 liters·mol ⁻¹ agrees very well with the experimentally measured values of 11.7 ± 0.3 for a montmorillonite reference clay and 11.8 ± 1.2 for a montmorillonite‐rich pelagic sediment. The proposed model is also general enough to describe the adsorption of any minor component in seawater which undergoes ion exchange.
Comparison of ammonium adsorption constants before and after the extraction of organic matter indicates that in organic‐rich sediments a “clay‐humic complex” may be controlling ammonium adsorption. However, in organic‐poor sediments, the clay mineralogy will tend to dictate ammonium adsorption behavior.
Ammonium adsorption by sediments plays an important role in the cycle of nitrogen in the estuarine tidal flat ecosystem. Ammonium adsorption on tidal flat sediments from the Yangtze estuary was studied using the simulation experiment. The findings indicated that there was linear adsorption by the tidal flat sediments for the lower ammonium concentration (<10mM) in the overlying waters. The adsorption coefficient of ammonium in the study area ranged from 3.81 to 9.00, and had a significant positive correlation with total organic carbon (r = 0.779, = 0.02284 , n=8), reflecting that organic matter might be one of the main factors controlling the behavior of ammonium adsorption. It also showed that salinity had a pronounced effect on ammonium adsorption, and that salinity affected the distribution of ammonium between the sediments and waters. The amount of ammonium adsorption on sediments gradually decreased with the increasing salinity. Especially within the range of lower salinity, just a little change of salinity had a dramatic influence on ammonium adsorption by sediments.
Quaternary sediments along a belt that extends from inland to bottom sediments of the Tyrrhenian Sea in southern Tuscany, Italy, are characterized by high concentrations of As (up to >1000 mg/kg). Earlier studies ascribed this anomaly to anthropogenic activities, e.g., past metallurgical processes of materials mined from pyrite and polymetallic deposits. Such activities, however, can only explain local anomalies. Alternatively, the extensive distribution of these high As contents in the Quaternary sediments is referred to a natural dispersion of eroded materials from ore deposits present in the area. This study provides fluid inclusion data in detrital quartz, as well as mineralogical and geochemical data of Quaternary sediments, from two contiguous catchments draining their waters toward the Tyrrhenian Sea. Results constrain the nature of the mineralized crust eroded and deposited in the coastal continental valleys and at the bottom of the Tyrrhenian Sea. Fluid inclusion data suggest that the As anomaly is related to the erosion of pyrite and polymetallic ore deposits, and that the original depth of the ore deposits ranged between about 500 and 2000 m. This shows that the erosion of such ores left an extensive legacy in southern Tuscany coastal valleys and in the Tyrrhenian sea.
Nitrogen pollution of groundwater has created problems worldwide. Riparian zones form a connection hub for terrestrial and aquatic ecosystems. As a potential source of ammonium in groundwater, aquitards have an important effect on the environment of riparian zones. The spatial distribution and factors influencing the ammonium content in the riparian zone aquitard of a small watershed were analyzed through three geological boreholes with increasing distances from the river: boreholes A > B > C. The results show that the distribution of ammonium was closely related to the lithology of sediments. Under the influence of the river and floods, the average content of ion exchange form of ammonium of sediments in borehole A (stable sedimentary environment) was 94.31 mg kg⁻¹, accounting for 21.2% of the transferable ammonium. The average proportions of ion exchange form of ammonium in the transferable ammonium of boreholes B and C (unstable sedimentary environment) were 19.1% and 17.4%, respectively. The carbonate and iron-manganese oxide forms of ammonium content of sediments in three boreholes were 0.96–15.28 mg kg⁻¹ and 2.3–54.4 mg kg⁻¹, respectively; this was mainly affected by the pH and Eh of the sedimentary environment. Organic sulfide, the form of transferable ammonium of sediments mainly exists in organic matter. The ammonium content in pore water generally increased with depth and was mainly derived from the mineralization of humic-like organic matter in borehole A. The ammonium in pore water in boreholes B and C mixed with ammonium from the mineralization of organic matter and the desorption of ion exchange form ammonium within sediments. The ammonium content in the pore water (up to 5.34 mg L⁻¹) was much higher than the limit for drinking water of 0.5 mg L⁻¹ in China. Therefore, the aquitard has a high risk of releasing ammonium and poses a certain threat to the quality of groundwater.
Capacitive deionization (CDI) offered a promising electrosorption technology for desalination. This study presented the feasibility of CDI for removing and recovering NH4⁺ from low-strength wastewater. The three-dimensional and porous reduced graphene oxide/titanium dioxide (rGO/TiO2) materials were successfully synthesized and investigated as potential material for CDI system. The structural and electrochemical properties of rGO and rGO/TiO2 composites were analyzed, while the incorporated TiO2 was anatase phase and TiO2/rGO mass ratio 20% delivered the best property. The effects of applied voltage, circulating flow rate, initial NH4⁺ concentration and regeneration conditions were investigated. The results demonstrated that rGO/20%TiO2 electrode performed much better electrosorption capacity and regeneration ability than the reference electrode (rGO electrode). Furthermore, NH4⁺ electrosorption onto CDI electrode followed the Freundlich adsorption isotherm and indicated a physisorption process according to kinetic studies. Additionally, hydrated radius and valence notably affected the alternative electro-behavior of CDI. In a co-existed system, electrosorption of ion highly depended on the ion charge rather than hydrated radius.
We have demonstrated that the entrapment of micro-sized zeolite particles (ZPs) in porous hydrogels is a promising strategy toward overcoming several drawbacks of ZPs and zeolite beads (ZBs) for adsorption of ammonium ions. The polyvinyl alcohol (PVA)-alginate-ZPs (PAZ) composite hydrogel beads with the same size as that of ZBs were prepared by physically entrapping the ZPs. On the basis of structural characterization results, the entrapped ZPs are well distributed with minimal agglomeration in the highly permeable and porous hydrogels. Unlike the ZPs, the PAZ hydrogels had good settleability and showed no significant further agglomeration of the entrapped ZPs even under high zeolite dosage conditions. Due to still high accessible surface area of the entrapped ZPs in the hydrogel, the maximum ammonium adsorption capacities of PAZ hydrogels from Langmuir isotherm were 3.4–4.3 times higher than those of ZBs. Thus, we propose that the entrapment of ZPs in highly porous hydrogel has much less adverse effects on the adsorption capacity, compared to the binder commonly used in the synthetic ZBs. Similar to the ZPs and unlike the ZBs, the ammonium adsorption process in the PAZ hydrogels was governed by chemical ion exchange mechanism and tended to be rate-limited by boundary layer diffusion and mainly intra-particle diffusion. Owing to the above-mentioned key features toward overcoming drawbacks of both the ZPs and the ZBs, the PAZ hydrogels have great potential as promising alternative zeolite-type adsorbents for a broad range of industrial applications in water purification and wastewater treatment.
Wastewater generated from different sources creates environmental problems after entering the aquatic ecosystem due to its heavy organic load and other undesirable toxicants. As a consequence, biological and chemical oxygen demand increases with depletion of oxygen level of water; all the biotic organisms suffer from stress-related symptoms often reaching to lethal limits. However, wastewater may become a useful resource for various economic-driven activities. Wastewater reuse is primarily dependent on the microbial degradation of different nutrients present in sewage. Thus, biogeochemical cycling bacteria have profound role on the decomposition, degradation and regeneration of nutrients from organic sewage water. Thus, the metabolism and turnover of the whole sewage-fed ponds are regulated by nutrient cycling and energy flow in the trophic level. Waste stabilization pond has been recognized as effective treatment system with removal of as high as 90–95% dissolved organic matter and reducing pathogens through microbial activities under aerobic and anaerobic conditions in trickling filter, activated sludge processes, etc. Interactions within and between carbon, nitrogen and phosphorus pools in nutrient cycles of wastewater-fed ponds ultimately result in nutrient removal from wastewater. A series of waste stabilization ponds (anaerobic, facultative and maturation) in which the detritus food chain is dominant over the grazing food chain is popular. It is evident that microbial activities play a crucial role in nutrient recovery from wastewater through microbial degradation of organic load leading to increased biological production while accelerating the enhancement of water quality through microbial-driven ecological processes.
Ubiquitous nonmotile marine microorganisms access dilute nutrients via diffusion
This paper present the first attempt to investigate the potential use of Yemeni (Al-Ahyuq) natural zeolite on the effectiveness of ammonium ion (NH4+) removal. The kinetics and isotherms of ion exchange were studied in a batch system. Important parameters which affect the ion exchange, such as optimal modified zeolite (SNZ), pH of solution, temperature, contact time, zeolite mass and initial ammonium concentration were investigated. The characteristics of modified zeolite (SNZ) and its mechanism of ammonium removal was investigated and compared with that of natural zeolite (NZ). Both zeolites were fully characterized by scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS) technique, zeta potential (Z-potential), X-ray diffraction (XRD), X-Ray Fluorescence (XRF),Fourier transform infrared spectroscopy (FTIR), thermogravimetry analyzes (TGA) and specific surface area (SSA) analysis. The results demonstrate that the SNZ has a high selectivity for NH4+ and had maximum removal efficiency reaching up to 99% based on relevant parameters. The highest ion exchange capacity was obtained at 35 degrees C and pH of 8. Moreover, the kinetic data followed more closely the pseudo-second order model whereas ion exchange isotherm was suitably described by the Langmuir model (LM). In addition to that, Kielland plots and thermodynamic parameters such as change in free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (Delta S degrees) were also calculated. The parameters revealed that the exchange process of ammonium ion by zeolite is spontaneous and exothermic The results indicate that the modified Yemeni zeolite has significant potential as an economic and effective adsorbent material for ammonium removal from aqueous solutions.
Nitrogen compounds in the interbedded turbiditic/pelagic sediments of the Madeira Abyssal Plain (from hereon MAP) have been divided in separate extracted fractions such as ‘exchangeable nitrogen’ (Nex), ‘fixed nitrogen’ (Nfix) and ‘organic nitrogen’ (Norg). Nex is found to be directly proportional to the amount of organic matter (Corg) in the sediment and is not related to the amount of ammonium in the porewater. Only at a relatively low Corg content is the Nex determined by the mineralogy of the sediment. The Norg as determined from Norg = (Ntot - Nfix - Nex) is strongly related with Corg. The Nfix content and the ratio for organic-rich sediments are high compared with other sediments and have not changed upon post-depositional oxidation of the organic matter.Post-depositional oxidation of organic matter through oxygen does lead to a decrease in the C/N ratio of the remaining organic matter in the organic-rich turbidites. The C/N ratio calculated for the organic matter that has been decomposed through oxygen is similar to that calculated through stoichiometric modelling for decomposition under reducing circumstances (C/N ratios of ≈ 17 and ≈ 18, respectively). This implies that for the sediments of the MAP, the C/N ratio is identical for organic matter decomposed under oxygenated and under reducing conditions.
Ammonium adsorption on sediments is an important process in aquatic environments where often about twice as much exchangeable NH4+ is found adsorbed on sediments as that measured in associated porewaters. Adsorption of NH4+ on fine-grained terrigenous sediments from the Louisiana Shelf west of the Mississippi River delta and from Lower Laguna Madre (LLM), Texas was studied under reducing and oxic conditions. Sediment from both sites yielded K* values of 2.3 and 4.0 ml g dw−1 under oxidizing and reducing conditions, respectively, even though the NH4+ concentration was about 10 times greater in Laguna Madre sediments than sediments from the Louisiana Shelf. K* determined under reducing conditions was a better predictor of exchangeable NH4+ in sediments from the two sites, based on NH4+ porewater concentrations, than K* determined under oxidizing conditions (the mean square error of reducing K* was ∼1/4 that of oxidizing K*). However, when considering potential NH4+ release from sediments if they are resuspended into overlying oxic waters, the oxic adsorption coefficient should be used.
Sediments can play an important role in estuarine ecosystems by buffering environmental nutrient concentrations in overlying waters. This study examined the role of surface chemistry in controlling the release of NH4+ from resuspended sediments in the large, shallow, negative estuary Laguna Madre, TX. Two techniques were used: a generally accepted elutriate method in which sediments were added at a 1:5 ratio to overlying water and a more dilute procedure (closed) where sediments were added at three ratios ranging from 1:10,000 to 1:100. In general, the more dilute procedure resulted in greater release of NH4+ from sediments. This is the result of the relative positions that the final solution concentrations place the systems on for an experimentally determined Langmuir-type adsorption isotherm. The closed system technique also indicated that approximately equal amounts of the released NH4+ came from porewater, loosely-bound quick-release, and tightly-bound slow-release fractions. Experimental results were supported by observations during dredging activities. Model calculations indicate that resuspension events may cause NH4+ releases comparable to NH4+ fluxes from bottom sediments. Resuspension could potentially contribute to such environmental problems in this estuary as the 'brown tide'. (C) 1999 Published by Elsevier Science B.V.
This reference provides a short refresher course in the most common engineering unit operations, such as distillation, solvent extraction, and crystallization; highlights the basic equations; presents empirical data for practical cases, and gives references to suitable literature; provides worked examples from engineering practice, stressing important aspects that may be overlooked by engineers who have not experienced similar problems. Table of Contents: Principles of diffusion. Distillation. Gas Absorption and Desorption. Solvent Extraction. Humidification. Drying of Solids. Adsorption and Ion Exchange. Crystallization. References. Appendixes. Index.
Abstract One important reaction which affects dissolved NH,+ distributions in marine sediments is re- versible adsorption,on sediment,solids. We investigate both the temperature,dependency,and spatial variability of the NH,+ linear adsorption coefficient, K, in marine scdimcnts. For a wide range of environments, because of approximately offsetting variations in sediment porosity and properties such as clay mineral and organic matter content, K is nearly constant (1.3 + 0.1) in terrigenous, surface, marine sediments. The value of K also does not vary significantly as a function of tem- perature. In biogenic,and,very,high porosity,(~0.95) sediments,K may,be somewhat,lower,than for other sedimentarv,environments.,Sediments,containing,seagrass detritus such as Thalassia may be expected,to exhibit,relatively high K values. Ammonium,is produced,in sediments
The aim of this study was assessment of ammonium (NH
4+) adsorption isotherms in some agricultural calcareous soils and modeling of that by using the mechanistic exchange model. Ten surface soils (0–30 cm) were collected from areas covered with different land uses in Hamedan, western Iran. Isotherm experiments were carried out by concentrations of NH
4+ prepared from NH4Cl salt (0, 10, 20, 30, 40, 50, 100, and 150 mg NH
4+ l−1) in presence of 0.01 M CaCl2 solution. The empirical models including simple adsorption isotherm and Freundlich equations were fitted well to the experimental data. The average amounts of adsorbed NH
4+ in studied soils varied from 8.95 to 35.23 %. Adsorption percentage indicated positive correlation with pH, cation-exchange capacity (CEC), equivalent calcium carbonate, and clay content and had negative correlation with sand content. In order to predict and model NH
4+ adsorption, cation-exchange model in PHREEQC program was used. The model could simulate the NH
4+ adsorption very well in all studied soils. The values of CEC played the major role in modeling of NH
4+ adsorption in this study indicating that cation-exchange process was the major mechanism controlling NH
4+ adsorption in studied soils.
Adsorption of NH4+ was measured for 15 North Sea sediments having different contents of organic matter and fine particles. Based on a previous study, the stations were grouped in three clusters: I, silty sediments; II, fine sands; and III, medium sands. The sediments span the range of erosive to depositional areas along the main transport route of particulate matter in the North Sea. Contents of organic carbon and fine particles (<6 μm), both providing potential sorption sites for the NH4+, followed this clustering with highest values in silty sediments and lowest in medium sand. Vertical profiles in the sediment of easily exchangeable NH4+ (EEA, extracted with 2m KCI in 2 h) showed lower contents in winter than in summer, with maximum values in the silty sediments (up to 2500 nmol g−1), and lowest in medium sand (<40 nmol g−1), Dimensionless distribution coefficients (ratio EEA:NH4+ dissolved in the pore water, corrected for porosity) were very high (> 100) in the upper 10 mm of some sediments, but were between 1 and 7 below 40 mm depth at all stations. Sorption isotherms were non-linear with steep slopes at NH4+ <40 μmol dm−3. Dimensionless sorption coefficients obtained from the slope of the isotherms were between 0.1 and 12.3 at NH4+, = 1 μmol dm−3, with large variation between stations. At NH4+ = 100 μmol dm−3, sorption coefficients were less variable between 0.2 and 0.9. The data suggest that the high coefficients at low concentrations are caused by sorption onto organic matter, which in turn is associated with clays and silt. Adsorption of NH4+, depends non-linearly on the concentration in the pore water, and the application of constant distribution coefficients to model NH4+, sorption can be a serious over-simplification of reality.
The magnitude of the exchange flux at the water–sediment interface was determined on the basis of the ammonia concentration gradient at the near-bottom water–interstitial interface and Fick's first law. It was established that in Puck Bay, ammonia almost always passes from the sediment to water. Ammonia flux varied from 5 to 1434 μmol NH4-N m−2 day−1. In total,c. 138·2 tonneammonia year−1pass from sediments of Internal Puck Bay to near-bottom water, the equivalent value for External Puck Bay being 686·9 tonne year−1. In total, about 825 tonne ammonia year−1passes from the sediment to near-bottom water of Puck Bay. In interstitial waters, ammonia occurred in concentrations varying over a wide range (3–1084 μmol NH4-N dm−3).The basic factors affecting the magnitude of ammonia concentration in interstitial waters included: oxidation of organic matter, type of sediment, and inflow of fresh underground waters to the region examined.This paper involves preliminary studies only and constitutes a continuation of the studies on ionic macrocomponents and phosphorus in interstitial waters of Puck Bay undertaken previously.
We conducted continuous-flow experiments on intact sediment cores from Laguna Madre, Sabine Lake, East Matagorda Bay, and Nueces Estuary to evaluate internal nitrogen (N) sources, sinks, and retention mechanisms in Texas estuaries having different salinities. Mean ammonium (NH4+) flux ranged from slight uptake (negative values) to NH 4+ production rates of about 300 μmol m-2 h-1 (units used for all N rates) and increased with salinity (p = 0.10). Net nitrate (NO3-) flux (-20 to 32) and net N 2 flux (-70 to 100) did not relate to salinity. Mean net N 2 flux was positive but near zero, indicating that N2 sources and sinks are nearly balanced. Total denitrification, N fixation, and potential dissimilatory NO3- reduction to NH 4+ (DNRA) rates were estimated after inflow water was enriched with 15NO3- (100 μmol L -1). Total denitrification rates ranged from 0 to 90 versus N fixation rates ranging from 0 to 97. Potential DNRA, measured conservatively as 15NH4+ accumulation, ranged from 0 to 80 and related significantly to salinity (p < 0.01). Increases in total NH 4+ release after 15NO3- additions were higher but closely related (r = 0.9998) to 15NH 4+ accumulation, implying exchange reactions of DNRA-regenerated 15NH4+ with sediment-bound 14NH4+. The fate of NO3- was related to salinity, perhaps via sulfide effects on DNRA. Potential DNRA was high in southeastern Corpus Christi Bay in August during hypoxia when the sulfide transition zone was near the sediment surface. Nitrogen fixation and DNRA are important mechanisms that add and retain available N in Texas estuaries. © 2006, by the American Society of Limnology and Oceanography, Inc.
Book Review: Early Diagenesis-A Theoretical Approach. RA Berner. Princeton Series in Geochemistry
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Effect of Salinity on NH4+ Exchange Behavior at the Sediment-Water Interface in East Chongming Tidal Flat
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Wang, D., Chen, Z., Qian, C., and Xu, S. (2002). Effect of Salinity
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Standard Methods for the Examination of Water and Wastewater
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