scholarly journals Kinetic Parameters of Denitrification in a River Continuum

1998 ◽  
Vol 64 (7) ◽  
pp. 2533-2538 ◽  
Author(s):  
Roberto García-Ruiz ◽  
Sarah N. Pattinson ◽  
Brian A. Whitton
Keyword(s):  
Kinetic Parameters ◽  
Sediment Cores ◽  
River System ◽  
Maximal Activity ◽  
Gas Production ◽  
River Continuum ◽  
Type Curve ◽  
Total N ◽  
Main River ◽  
Acetylene Blockage

ABSTRACT Kinetic parameters for nitrate reduction in intact sediment cores were investigated by using the acetylene blockage method at five sites along the Swale-Ouse river system in northeastern England, including a highly polluted tributary, R. Wiske. The denitrification rate in sediment containing added nitrate exhibited a Michaelis-Menten-type curve. The concentration of nitrate for half-maximal activity (Kmap ) by denitrifying bacteria increased on passing downstream from 13.1 to 90.4 μM in the main river, but it was highest (640 μM) in the Wiske. The apparent maximal rate (Vmaxap ) ranged between 35.8 and 324 μmol of N m−2 h−1 in the Swale-Ouse (increasing upstream to downstream), but it was highest in the Wiske (1,194 μmol N m−2 h−1). A study of nitrous oxide (N2O) production at the same time showed that rates ranged from below the detection limit (0.05 μmol of N2O-N m−2 h−1) at the headwater site to 27 μmol of N2O-N m−2 h−1 at the downstream site. In the Wiske the rate was up to 570 μmol of N2O-N m−2 h−1, accounting for up to 80% of total N gas production.

An Assessment of Environmental Changes in Three Lakes from King's County (Nova Scotia, Canada) Using Diatom-Based Paleolimnological Techniques

2008 ◽  
Vol 43 (2-3) ◽  
pp. 85-98 ◽  
Author(s):  
Joshua R. Thienpont ◽  
Brian K. Ginn ◽  
Brian F. Cumming ◽  
John P. Smol
Keyword(s):  
Nova Scotia ◽  
Environmental Changes ◽  
Sediment Cores ◽  
Lake Management ◽  
River System ◽  
210Pb Dating ◽  
Hydroelectric Power ◽  
Diatom Assemblages ◽  
Shoreline Development ◽  
Before And After

Abstract Paleolimnological approaches using sedimentary diatom assemblages were used to assess water quality changes over the last approximately 200 years in three lakes from King's County, Nova Scotia. In particular, the role of recent shoreline development in accelerating eutrophication in these systems was assessed. Sediment cores collected from each lake were analyzed for their diatom assemblages at approximately 5-year intervals, as determined by 210Pb dating. Analyses showed that each system has changed, but tracked different ecosystem changes. Tupper and George lakes recorded shifts, which are likely primarily related to climatic warming, with diatom assemblages changing from a preindustrial dominance by Aulacoseira spp. to present-day dominance by Cyclotella stelligera. In addition to the recent climatic-related changes, further diatom changes in the Tupper Lake core between approximately 1820 and 1970 were coincident with watershed disturbances (farming, forestry, and construction of hydroelectric power infrastructure). Black River Lake has recorded an increase in diatom-inferred total phosphorus since about 1950, likely due to impoundment of the Black River system for hydroelectric generation and subsequent changes in land runoff. Before-and-after (i.e., top-bottom) sediment analyses of six other lakes from King's County provided further evidence that the region is being influenced by climatic change (decreases in Aulacoseira spp., increases in planktonic diatom taxa), as well as showing other environmental stressors (e.g., acidification). However, we recorded no marked increase in diatom-inferred nutrient levels coincident with shoreline cottage development in any of the nine study lakes. Paleolimnological studies such as these allow lake managers to place the current limnological conditions into a long-term context, and thereby provide important background data for effective lake management.

RIONET: a water quality management tool for river basins

2003 ◽  
Vol 48 (10) ◽  
pp. 47-53 ◽  
Author(s):  
H. Reuter ◽  
G. Krause ◽  
A. Mönig ◽  
M. Wulkow ◽  
H. Horn
Keyword(s):  
Water Quality ◽  
Quality Management ◽  
Waste Water Treatment ◽  
Sediment Cores ◽  
Water Quality Management ◽  
River Basins ◽  
Bulk Water ◽  
Management Tool ◽  
Quality Model ◽  
Main River

The water quality management tool RIONET for river basins has been developed with regard to the EU Water Framework Directive. The management tool can simulate the water quality in catchment basins not only in the dimension of a single river but in whole river networks. A submodel of the IWA River Water Quality Model No. 1 is used in RIONET. The river model is based on the assumption that self purification processes in the river takes place both in the benthic biofilm and the bulk water phase. Laboratory experiments with sediment cores underline the major role of the benthic biofilm. The input parameters of the management tool such as volumetric flow rates from waste water treatment plants and flow velocities and discharge in the main river and its tributaries can be loaded directly from geographic information systems (GIS). The subcatchment basin of the river Bode in Saxon Anhalt was used for test runs of RIONET.

199 Do the Microbiomes of Horses Process Nutrients Differently Based on Keeper Status?

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 106-106
Author(s):  
Alexa C Johnson ◽  
Amy S Biddle
Keyword(s):  
Fixed Effects ◽  
High Performance ◽  
16S Rrna Gene Sequencing ◽  
Gas Production ◽  
Rrna Gene ◽  
Total N ◽  
Fermentation Products ◽  
Fecal Samples ◽  
Α Diversity ◽  
C 50

Abstract This study reports the differential response of the equine gut microbiome to protein and/or carbohydrate based on keeper status (easy keeper (EK), medium keeper (MK), hard keeper (HK)). Anaerobic equine fecal samples (n = 12 total, n = 3 / EK, MK, HK of four breeds) inoculated microcosms with three dietary conditions (C = Carb (cornmeal), P = Protein (soybean meal), and M = mix (50% C, 50% P)). Over 48 hours, fermentation products were measured using colorimetric assays and high-performance liquid chromatography. Microbial populations were surveyed using 16S rRNA gene sequencing analyzed by QIIME2. Linear mixed models were fit with fixed effects of Treatment and Keeper status and their interactions, with random effects of HorseID. Differences in fermentation products by keeper status included: MK had higher pH and greater gas production, EK produced higher hydrogen sulfide, and HK had greater total protein. Total SCFA was not different between keeper status (P = 0.89) but the acetate: propionate ratio was highest for HK (2.45mM) and lowest for EK (1.85mM) (P = 0.05). Isobutyrate production was highest in HK (2.34mM) compared to MK (0.85mM) and EK (0.17mM). Treatment had significant effects across all measurements; M and C treatment values were similar reflecting microbial preferences for carbohydrates before protein. P treated trials had increased fermentation outputs due to lower acidity effects. Keeper status had no effect on α-diversity (P > 0.05) however HK horses were least affected by treatments. P treated samples were more diverse than C and M (P < 0.001). Spearman correlation of Keeper x Treatment identified Oligosphaeria spp. in EK (r = 0.49) and Fusobacteria spp. in HK whole fecal samples (r = 0.37). These data suggest that while the compositions of the gut microbiomes of keeper groups were similar, they were functionally different in processing key nutrients.

High prevalence of non-native fish species in a remote region of the Mamberamo River, Indonesia

2020 ◽  
Vol 26 (3) ◽  
pp. 293
Author(s):  
Arif Wibowo ◽  
Dwi Atminarso ◽  
Lee Baumgartner ◽  
Anti Vasemagi
Keyword(s):  
Native Species ◽  
River System ◽  
New Guinea ◽  
Current Status ◽  
Native Fish ◽  
Fish Diversity ◽  
Main River ◽  
Main River Channel ◽  
High Prevalence ◽  
Major River

Indonesian freshwater fish diversity is threatened by human activities such as logging, land clearing, pollution and introduction of non-native species. The latter may pose serious threats to endemic freshwater fauna even in relatively pristine and isolated habitats. One such area, West Papua in the island of New Guinea, is one of the least studied regions in the world and a biodiversity hotspot. The Mamberamo River contains the highest proportion of non-native fish compared to other major river systems in New Guinea. To document this, we conducted a field study to validate and further temporally characterise the fish biodiversity to ascertain its current status. Since the last ichthyological survey 15 years ago, we detected two additional non-native species (Leptobarbus melanopterus and Oreochromis niloticus) that have established in the river system. Moreover, our survey revealed that non-native fish are extremely common in the mid reaches of the Mamberamo River, comprising 74% of total catch, with non-native Barbonymus gonionotus (family Cyprinidae) now established as the dominant species. The biomass of non-native B. gonionotus now exceeds that of all native fish combined in the main river channel. These results highlight the serious threat of invasive species in remote regions that support high levels of endemic biodiversity. Plans for containment, prevention through education programmes, and management are urgently required.

scholarly journals Facies association and depositional environment of fan-delta sequence in southwest Kathmandu Basin, Nepal

1970 ◽  
Vol 12 ◽  
pp. 1-16
Author(s):  
Naresh Kazi Tamrakar ◽  
Pramila Shrestha ◽  
Surendra Maharjan
Keyword(s):  
River System ◽  
Sedimentary Facies ◽  
Facies Association ◽  
Base Level ◽  
Rock Types ◽  
Fan Delta ◽  
Main River ◽  
Facies Associations ◽  
Delta Sequence ◽  
The Difference

Lake marginal sedimentation prevailed around the Paleo-Kathmandu Lake. Owing to the difference in local basin conditions; tectonics, source rock types and river systems therein, the lake marginal environments and sedimentary facies associations differ around the Paleo-Kathmandu Lake. In this study, the basin-fill sediments of southwestern margin of the Kathmandu Basin were studied for the sediments recorded in vertical sequences at various localities and facies analysis was made. Mainly eight facies were recognised. They were matrix-supported massive gravel (Gmm), matrix-supported graded gravel (Gmg), gravelly fine or mud (GF), massive silt (Fsm), massive mud (Fm), ripple-laminated silt or laminated silt/mud/clay (Fl), carbonaceous clay (C), and incipient soil with roots (Fr). Four facies associations that were identified were proximal fan-delta facies association (FA1), mid fan-delta facies associaiton (FA2), distal fan-delta facies association (FA3), and gravelly sinuous river facies association (FA4). Remarkably, these facies associations do not contain any sandy facies and foreset bedding of Gilbert-type. The fan-delta region was characterised by flood-dominated flows and vertical accretion of fines in the flood basins, and vegetated swamps rich in organic sediments. The distribution of facies associations suggests extensive lake transgression followed by rapid lake regression. The recent river system then incised the valley against local upliftment due to faulting or lowering of base level of the main river in the Kathmandu Basin probably related to draining out of the lake water. doi: Bulletin of the Department of Geology, Vol. 12, 2009, pp. 1-16

Denitrification and nitrate leaching during the fall and winter following dairy cattle slurry application

1997 ◽  
Vol 77 (2) ◽  
pp. 231-240 ◽  
Author(s):  
J. W. Paul ◽  
B. J. Zebarth
Keyword(s):  
Dairy Cattle ◽  
Soil Profile ◽  
High Water ◽  
High Rate ◽  
Cattle Slurry ◽  
Manure Application ◽  
Total N ◽  
Acetylene Blockage Technique ◽  
Acetylene Blockage ◽  
Dairy Cattle Slurry

Conditions in soils of south-coastal British Columbia during the fall and winter favor both NO3− leaching and denitrification. Estimates of NO3− leaching were made on a coarse-textured soil having a high water table (Sumas) and a well-drained, medium-textured soil (Agassiz) in each of 1991 and 1992, following application of 0, 300 and 600 kg total N ha−1 as dairy cattle slurry at the end of September. Leaching was calculated by measuring NH4+ and NO3− concentrations biweekly to 90 cm depth and subtracting denitrification losses. Denitrification estimates were made using the acetylene blockage technique on intact cores taken to 43 cm depth at biweekly intervals from the 0 and 600 kg N ha−1 treatments. Most of the NO3− disappeared from the 90 cm soil profile by January in both years. At the high rate of manure application, denitrification losses were 29 and 20 kg N ha−1 at Agassiz in 1991 and 1992, and 48 and 17 kg N ha−1 at Sumas in 1991 and 1992, respectively. Denitrification losses in the non-manured treatments ranged from 3 to 16 kg N ha−1 Significant denitrification losses occurred at the 15- to 28-cm and the 30-cm to 43-cm depths, indicating that denitrification measurements at these depths are important. Leaching losses ranged from 60 to 188 kg N ha−1 from the control treatments, and from 102 to 241 kg N ha−1 following the highrate of manure application. Denitrification accounted for up to 17% of the NO3− loss from the soil profile, indicating that the majority of the NO3− was leached. Key words: Acetylene blockage technique, denitrification rate, air-filled porosity, manure

Paleolimnology of a fluvial lake downstream of Lake Superior and the industrialized region of Sault Saint Marie

2005 ◽  
Vol 62 (11) ◽  
pp. 2586-2608 ◽  
Author(s):  
Euan D Reavie ◽  
John A Robbins ◽  
Eugene F Stoermer ◽  
Marianne SV Douglas ◽  
Gail E Emmert ◽  
...  
Keyword(s):  
20Th Century ◽  
Anthropogenic Activities ◽  
Lake Superior ◽  
Sediment Cores ◽  
Chemical Properties ◽  
River System ◽  
Geochemical Data ◽  
Fluvial Lake ◽  
Lotic System ◽  
Contaminant Metals

A paleolimnological study was undertaken to describe the past environment of the St. Mary's River downstream of Lake Superior. Two sediment cores were obtained from the deepest part of Lake George, a fluvial lake in the river system. Rigorous analyses of radionuclides (210Pb, 226Ra, and 137Cs) and chemical properties provided an accurate sediment chronology. More than 450 diatom species from 47 genera were identified. Diatom and geochemical data indicated gradual environmental change in response to anthropogenic activities, including logging, hydrologic manipulation, and steel, leather, and paper industries. A decline in water quality occurred gradually from the late 1800s through the 20th century in response to human activities, as was apparent from an increase in eutrophic–planktonic diatom taxa. A decline in benthic taxa and an increase in contaminant metals were also contemporaneous with impacts during the 20th century. Subfossil diatoms were similar to those recorded in paleolimnological investigations from the Great Lakes. However, diatom profiles indicate that the algal supply from upstream Lake Superior has been minimal and that the cores mainly reflect environmental characteristics of the near-upstream environment. Despite stochastic sedimentary regimes and complex habitats in the lotic system, this study reinforces the value of river paleolimnology at carefully selected sites.

scholarly journals Kinetic Study on Biogas Production from Cabbage (Brassica oleracea) Waste and Its Blend with Animal Manure Using Logistic Function Model

2021 ◽  
pp. 34-43
Author(s):  
Christian C. Opurum
Keyword(s):  
Anaerobic Digestion ◽  
Kinetic Parameters ◽  
Goodness Of Fit ◽  
Biogas Production ◽  
Logistic Function ◽  
Gas Production ◽  
Cow Dung ◽  
Function Model ◽  
Biogas Yield ◽  
Significant Difference

This research paper aimed to evaluate the kinetics of anaerobic digestion (AD) of mixtures of cabbage waste (CW) with (Poultry dropping (PD) and Cow dung (CD). The study was conducted in 10L bio-digesters for 35 days under mesophilic conditions (25 - 35OC). Logistic function equation was used to simulate the experimental data to test for its goodness of fit and kinetic parameters namely: maximum biogas potential (Pb), the maximum biogas production rate (Rm), and the lag phase duration (λ) were estimated in each treatment. Chemical analysis showed that individual substrates possess characteristics that could support microbial activities in biogas production. The biogas yield in terms of added  volatile solids (VS) in decreasing order was as follows: 0.022, 0.018, 0.017, 0.014, 0.014 and 0.013 dm3/g VS for CW/CD 2:1, CW/PD3:1, CW/CD 1:1, CW alone, CW/PD1:1 and  CW/PD 2:1, respectively. A significant difference (P ≤ 0.05) in biogas yield was recorded in CW/CD 2:1 with 7.19 dm3 (53.29% increase). The kinetic parameters (Pb, Rm, and λ) for CW/CD 2:1 was 7.01 dm3, 1.58 dm3.d, and 2.29 days, respectively. This was followed by CW/PD 3:1 (5.84 dm3); with 24.92% increase in gas production and CW/CD 1:1 (5.42 dm3) with 15.53% increase relative to CW alone, 4.69 dm3. The digesters fed with CW/PD 1:1 and CW/PD 2:1 exhibited inhibitory effects on biogas production, with 7.51 and 2.05% decrease in gas yield, respectively. The logistic function model demonstrated a strong relationship between the experimental and model-predicted data. The high correlation coefficient (R2) ranging between 0.978 - 0.993 is evident. The model proved to be a useful tool in predicting anaerobic digestion and biogas production process.

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