production, high concentrations of urea and NH, , and high sediment-water exchange rates of urea and NHdf Based on a conceptual model of nitrogen mineralization in the Bering Shelf/Anadyr sediment, it was suggested that urea hydrolysis could be responsible for up to 80 of the gross production of NH4...
Total hydrolysable amino acids THAAs constitute the most important fraction of labile nitrogen Anthropogenic activities directly influence various biogeochemical cycles and then accelerate lake ecosystem deterioration This is the first study that has established the relationship between sediment THAAs and anthropogenic activities using dated sediment cores, and evaluated the ,...
Nov 30, 2000 0183 32 The Chesapeake Bay River-Input Monitoring Program was established to characterize the water quality of four major rivers in Maryland, and to quantify the load and the long-term trends in concentrations of nutrients nitrogen and phosphorus and suspended sediment transported from the nontidal part of each river to the Chesapeake Bay As part of ,...
Denitrification of sediments is an important way to remove reactive nitrogen in lakeshore zon In this work, we analyzed sediment denitrification patterns across the shore zone of Lake Taihu and explored their underlying mechanisms using flooding simulation experiments The results showed that denitrification mainly occurred in the upper sediment layer 0 ndash 10 cm and ,...
In Kaneohe Bay, Hawaii sediment nitrogen fixation has been calculated to contribute 11 of the annual nitrogen input Nitrogen budgets calculated by Smith 70 for Shark Bay, Australia and two Pacific island atolls suggest that nitrogen fixation is the principal nitrogen input into these oligotrophic ecosystems...
Surface sediment and water samples were collected from Daihai Lake to study the biogeochemical characteristics of nitrogen and phosphorus, to estimate the loads of these nutrients, and to assess their effects on water quality The contents and spatial distributions of total phosphorus TP , total nitrogen TN , and different nitrogen forms in sediments were ,...
NOG Jørgensen, in Encyclopedia of Inland Waters, 2009 Dissolved organic nitrogen DON compounds in lakes and rivers originate from photosynthetic organisms algae and plants and excretion of nitrogenous waste by animals, but leachate from soil, sewage discharge, and atmospheric deposition can also contribute organic nitrogen to the water Since most of the ,...
Apr 02, 2021 0183 32 Nitrogen total balance experiments determined that Bzr02 and Str21 incorporated nitrogen into cell biomass up to 947 and 747 , respectively , suggesting that nitrogen assimilation was also an....
Nutrients and sedimentation were monitored for approximately 2 years at six sites in the St Thomas East End Reserves STEER , St Thomas, USVI, as part of a NOAA project to develop an integrated environmental assessment Concentrations of ammonium NH 4 ,...
Mar 13, 2019 0183 32 River restoration projects focused on altering flow regimes through use of in-channel structures can facilitate ecosystem services, such as promoting nitrogen N storage to reduce eutrophication In this study we use small flux chambers to examine ammonium NH4 and nitrate NO3- cycling across the sediment-water interface Paired restored and ,...
Mean annual net sediment yield from the reservoir basin was estimated to be 411,000 pounds per square mile per year Information from sediment cores shows that throughout the history of John Redmond Reservoir, total nitrogen concentrations in the deposited sediment generally were uniform indicating consistent nitrogen inputs to the reservoir...
Dec 15, 2021 0183 32 Later in the summer, nitrogen-fixing cyanobacteria can also contribute to OM export towards the sediment, and support benthic secondary production to ,...
nium-nitrogen was determined by ex traction with 2 N KC1 and steam dis tillation of the extract with MgO 17 Water soluble ammonium-nitrogen and nitrate nitrite -nitrogen in the in terstitial water removed from the sediment were determined by a steam distillation technique 18 and nitrite nitrogen by the Griess-Ilosvay proce dure 19...
Sedimentation flux was equally high 5380 and 18 mg m -2 d -1 for both nitrogen and phosphate input, mainly from the Sebou River and in particulate form which immediately settles upon arrival in the reservoir...
Stormwater ponds should be dredged when the permanent pool volume is half-filled with sediment because the pond is no longer effectively removing sediment and pollutants once filled to that level For instance, if a stormwater pond was constructed to have an average depth of 6 feet, it will need to be dredged when the average depth reaches 3 ....
Sedimentation is a physical water treatment process that uses gravity to remove suspended solids from water Solid particles set in motion by water turbulence can be removed naturally through sedimentation in a still body of water, such as ponds or lak The settling tanks are structures built to collect the solids carried by sedimentation...
Some have even suggested that alterations to the nitrogen cycle may lead to an increased risk of parasitic and infectious diseases among humans and wildlife Johnson et ,...
Regression analysis suggested that the production was positively influenced by the concentration of organic compounds in the pond water The ammonium concentration in the range of 20-60 mg/l NH 4-N did not affect duckweed production Fifty-six percent of the pond influent nitrogen, mainly ammonium, was removed...
Sediment profiles of particulate organic carbon and nitrogen, sediment acid-hydrolyzable amino acids, DON, DFAA, urea, NH and the turnover rate of urea were measured at four1 4 , suggested that the large pool of dead organic matter in sediments may reflect the low rate at which 1 Present address Research Center Foulum, Post box 50, DK-8830 ....
Jun 24, 2020 0183 32 Achieving nitrogen N and phosphorus P control in sediment remediation projects by adding natural materials is receiving increasing attention In this study, different natural materials, including iron-rich clay minerals, calcite, kaoline, sugarcane bagasse and Phragmites detritus, were applied to test their effects on N and P in a mesocosm experiment...
N2 - Simulated agricultural runoff, amended with sediment, nitrogen, and phosphorus, was run through an experimental sedimentation basin Perforated risers created 3-day and 1-day detention tim Effluent concentrations were monitored for total suspended sediments and various forms of nitrogen and phosphorus...
Nov 15, 2021 0183 32 Nitrogen and phosphorus are key elements in controlling eutrophication in the aquatic system Water and sediment samples were collected from Hongfeng Lake, a seasonally stratified reservoir in southwest China, in winter and summer...
Apr 10, 2021 0183 32 The sedimentation rate partly determines the amount of nitrogen removed from the water Griffiths and Mitsch 2020 The loss of nitrogen from seawater caused by sedimentation depends on two factors the sedimentation rate and the amount of nitrogen contained in sinking particles Zhang et al 2015 These two factors together determine the ,...
Nitrogen losses associated with sediment in the runoff accounted for 92 of the total loss for the Byear period from the contour- , Watersheds 2 and 3 received the normal, recommended fertilizer applicationrates of 168 kg N/ha and 39 kg Plha in 1969, 1970, and 1971 Anhydrous ammonia was knifed in to a depth of 25 to 35...
Oct 21, 2021 0183 32 This study investigated the response of sediment nitrogen fixation to the degradations of algae and macrophyte residues through continuous flow mesocosms combined with nifH sequencing analysis and isotope tracing The results suggested that the active nitrogen fixation of sediments only occurred in the first two weeks of the rapid degradation ....
15N δ18O ratio suggested that most of the outgassing N 2O was derived from incomplete denitrification in sediment pore water Overall, there was a net export of dissolved inorganic nitrogen from mangroves toward the estuary in winter and spring but a net import to...
46 detention times of a primary sedimentation tank Colloidal solids readily pass through the primary 47 treatment process and are treated in the secondary treatment process Primary sedimentation 48 tanks reduce the wastewater velocity to less than 03 m/s 10 ft/sec and allow these settleable 49 solids to separate from the waste stream...
Sediment and nutrient transport in the School Branch watershed in central Indiana west of Indianapolis is considered to be heavily affected by agricultural land use throughout the watershed In 2015, the US Geological Survey, in cooperation with the Indiana Department of Environmental Management, deployed continuous water-quality monitors and began collecting ,...
Aug 29, 2012 0183 32 Concentrations of nitrogen, phosphorus, and suspended sediment are measured at the US Geological Survey streamgage at Conowingo Dam at the downstream end of the Susquehanna River Basin in Maryland, where the river flows into the Chesapeake Bay During the period September 7-15, 2011, in the aftermath of Tropical Storm Lee, concentrations of these ,...
13 Temporal trends of flow-weighted total nitrogen, total phosphorus, and suspended-sediment concentrations computed from daily mean load regression equations at five US Geological Survey streamgages in the Eucha-Spavinaw drainage area, ,...