Complete carbon and nitrogen budgets for the hydromedusaCladonema californicum (Anthomedusa: Cladonemidae)

1991 ◽  
Vol 108 (1) ◽  
pp. 119-128 ◽  
Author(s):  
J. Costello
Keyword(s):  
Nitrogen Budgets ◽  
Carbon And Nitrogen

Investigation of the Contribution of Natural Organic Runoff to Dissolved Oxygen Depletion in the Red Deer River

1979 ◽  
Vol 14 (1) ◽  
pp. 71-88
Author(s):  
S.E. Penttinen ◽  
P.H. Bouthillier ◽  
S.E. Hrudey
Keyword(s):  
Dissolved Oxygen ◽  
Red Deer ◽  
Stream Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Experimental Program ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Tributary Stream ◽  
Small Tributary

Abstract Studies on the chronic low dissolved oxygen problems encountered under winter ice in the Red Deer River have generally been unable to account for dissolved oxygen depletion in terms of known manmade inputs. An experimental program was developed to assess the possible nature and approximate bounds of oxygen demand due to natural organic runoff carried to the Red Deer River by a small tributary stream, the Blindman River. The study employed an electrolytic respirometer on stream water samples subjected to prior concentration by vacuum evaporation. Evaluation of carbon and nitrogen budgets in conjunction with the measured oxygen demand indicate that biochemical oxygen demand is originating with natural organic runoff in tributaries of the Red Deer River. The results provide a basis for estimation of the possible contribution to the observed oxygen demand in the Red Deer River originating from natural organic runoff.

Carbon and nitrogen budgets of a winter rapeseed field in Estonia: a methodology for the quantification of all relevant pools and fluxes

2021 ◽  
Author(s):  
Jordi Escuer-Gatius ◽  
Krista Lõhmus ◽  
Merrit Shanskiy ◽  
Karin Kauer ◽  
Hanna Vahter ◽  
...  
Keyword(s):  
Mass Balance ◽  
Environmental Parameters ◽  
Balance Method ◽  
Nitrogen Budgets ◽  
N Cycle ◽  
Carbon And Nitrogen ◽  
Mass Balance Method ◽  
C Cycle ◽  
Winter Rapeseed ◽  
C And N

<p>Agricultural activities can have several adverse impacts on the environment; such as important greenhouse gas (GHG) emissions. To implement effective mitigation measures and create effective policies, it is necessary to know the full carbon and nitrogen budgets of agro-ecosystems. However, very often, information regarding the pools or fluxes involved in the carbon and nitrogen cycles is limited, and essential complementary data needed for a proper interpretation is lacking.</p><p>This study aimed to quantify all the relevant pools and fluxes of a winter rapeseed, a widely spread crop in the Europe and Baltic regions. The N<sub>2</sub>O and CH<sub>4</sub> fluxes were measured weekly using the closed static chamber method from August 2016 to August 2017 in a winter rapeseed field in Central Estonia. Additionally, nutrient leaching and soil chemical parameters, as well as environmental parameters like soil moisture, electrical conductivity and temperature were monitored. At the end of the season, the rapeseed and weed biomasses were collected, weighed and analyzed. The remaining relevant fluxes in the N cycle were calculated using various non-empirical methods: NH<sub>3</sub> volatilization was estimated from slurry and environmental parameters, N deposition and NO<sub>x</sub> emissions were obtained from national reports, and N<sub>2</sub> emissions were calculated with the mass balance method. Regarding the C cycle, gross primary production (GPP) of the rapeseed field was also calculated by the mass balance method. Simultaneously, for comparison and validation purposes, GPP was estimated from the data provided by MOD17A2H v006 series from NASA, and N<sub>2</sub> was estimated from the measured emissions of N<sub>2</sub>O using the N<sub>2</sub>:N<sub>2</sub>O ratio calculated from the DAYCENT model equations.</p><p>N<sub>2</sub> emissions and GPP were the biggest fluxes in the N and C cycles, respectively. N<sub>2</sub> emissions were followed by N extracted with plant biomass in the N cycle, while in the carbon cycle soil and plant respiration and NPP were the highest fluxes after GPP. The carbon balance was positive at the soil level, with a net increase in soil carbon during the period, mainly due to GPP carbon capture. Contrarily, the nitrogen balance resulted in a net loss of N due to the losses related to gaseous emissions (N<sub>2</sub> and N<sub>2</sub>O) and leaching.</p><p>To conclude, it was possible to close the C and N budgets, despite the inherent difficulties of estimating the different C and N environmental pools and fluxes, and the uncertainties deriving from some of the fluxes estimations.</p>

Carbon and nitrogen budgets and respiration rates of selected foraminifera of the Gullmar Fjord in Sweden

2021 ◽  
Author(s):  
Julia Wukovits ◽  
Nicolaas Glock ◽  
Johanna Nachbagauer ◽  
Petra Heinz ◽  
Wolfgang Wanek ◽  
...  
Keyword(s):  
Benthic Foraminifera ◽  
Environmental Changes ◽  
Microscopy Imaging ◽  
Test Volume ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Respiration Rates ◽  
Feeding Experiments ◽  
Nitrogen Intake ◽  
Oxygen Concentrations

<p>Benthic foraminifera are highly abundant, ubiquitous marine protists, with many species feeding on microalgae or phytodetritus. Knowledge about carbon and nitrogen budgets and metabolic activities of benthic foraminifera can help to increase our understanding about their ecology and their role in aquatic biogeochemistry at the sediment-water interface. This can further increase their application as proxies for environmental changes. Shifts in the benthic foraminiferal communities of the Swedish Gullmars Fjord document the shift from well oxygenated bottom waters to seasonal hypoxia at its deepest location the Alsbäck Deep (125 m), during the last century.</p><p>So far there are only investigations available relating foraminiferal community composition with increased primary productivity and resulting hypoxia in this Fjord. In contrast, studies about the species-specific feeding ecology or food derived foraminiferal carbon and nitrogen fluxes are scarce.</p><p>Therefore, laboratory feeding experiments and respiration rate measurements were carried out with <em>Bulimina marginata</em>, <em>Cassidulina laevigata</em> and <em>Globobulima turgida</em>, abundant foraminifera in such environments, collected in August 2017.</p><p>Experiments were conducted to evaluate the carbon and nitrogen intake and turnover of dual (<sup>13</sup>C and <sup>15</sup>N) isotope labelled <em>Phaeodactylum tricornutum</em> detritus; detritus of a common diatom in the Gullmar Fjord. For the feeding experiments, foraminifera were incubated at 9.1°C in the dark, in sterile filtered seawater at ambient oxygen concentrations. The foraminifera were fed for a period of 24 hours and subsequently incubated without food for another 24 hours. After each incubation cycle, foraminiferal respiration rates were measured. The individuals were analyzed via Elemental Analyzer-Isotope Ratio Mass Spectroscopy to evaluate <sup>13</sup>C/<sup>12</sup>C and <sup>15</sup>N/<sup>14</sup>N ratios and their bulk content of organic carbon and nitrogen.</p><p>Additionally, we present carbon and nitrogen to volume ratios for the foraminifera <em>B. marginata</em>, <em>C. laevigata</em>, <em>G. turgida</em>, <em>G. auriculata</em> and <em>Nonionella turgida</em>, as derived from elemental analysis and light microscopy imaging.</p><p>The results show, that <em>B. marginata</em>, an opportunistic species associated with high fluxes of organic matter, had the highest rate of specific carbon and nitrogen intake and turnover. <em>Cassidulina laevigata</em>, a species that co-occurs with fresh phytodetritus and does not tolerate very low oxygen concentrations, showed lower carbon and nitrogen intake rates. <em>Globobulima turgida</em>, a denitrifying infaunal species that thrives under hypoxia, showed the lowest specific carbon and nitrogen intake and turnover rates. Respiration rates of all species did not depend on incubation with or without a food source. The foraminifera showed similar carbon and nitrogen densities per test volume across all species.</p><p>Overall this study helps to improve the knowledge on the nutritional ecology of the investigated species, demonstrating the close relation between feeding/metabolic rates and their environmental niche and highlighting the need to introduce foraminiferal data in future marine carbon and nitrogen flux models.</p>

Predicting microbial redox dynamics and nutrient cycling in the subsurface considering spatio-temporal heterogeneities

2020 ◽  
Author(s):  
Swamini Khurana ◽  
Falk Heße ◽  
Martin Thullner
Keyword(s):  
Nutrient Cycling ◽  
Temporal Dynamics ◽  
Regional Scale ◽  
Water Flux ◽  
Biogeochemical Cycles ◽  
Ecosystem Functions ◽  
Microbial Dynamics ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Nitrogen Cycles

<p>Biogeochemical cycles are extensively studied as they control the flow of matter (carbon and nitrogen, specifically) up to the global scale, further impacting ecosystem functions and services. To be able to predict carbon and nitrogen budgets, it is necessary to study carbon and nitrogen cycles in all compartments of the biosphere, from forests to water, to soil and deep subsurface. Since the soil and deeper subsurface compartments store a high share of the global carbon and nitrogen budget, it is necessary to study the carbon and nitrogen cycles in the subsurface at a higher resolution. Given the spatial heterogeneity and temporal dynamics exhibited by the subsurface, coupled with lack of observational opportunities, the prediction of these cycles in the subsurface is a challenge. For this purpose, this study aims to resolve microbial mediated carbon and nitrogen dynamics in the subsurface with respect to spatial and temporal heterogeneity using a numerical modeling approach. The model considers the response of microbial growth and activity to varying environmental conditions such as access to nutrients and energy sources.</p><p>The obtained results show a linear relationship between the relative impact on carbon and nitrogen removal and relative difference in breakthrough times between homogeneous scenarios and the spatially heterogeneous scenarios. In contrast, the temporal dynamics of changing flow rates induces minimal aggregated impact on the carbon and nitrogen cycles in the subsurface. This implies that short term temporal dynamics do little to influence the long-term nutrient cycles, given the same average water flux through the entire simulation period. The findings of this study can assist in identification of drivers of microbial dynamics and nutrient cycling in the Critical Zone. This, in turn, can assist towards the regional scale modeling of biogeochemical cycles resulting from microbial dynamics.</p>

Biochar amendment and water stress alter rhizosphere carbon and nitrogen budgets in bauxite-processing residue sand under rehabilitation

2019 ◽  
Vol 230 ◽  
pp. 446-455 ◽  
Author(s):  
Mehran Rezaei Rashti ◽  
Maryam Esfandbod ◽  
Ian R. Phillips ◽  
Chengrong Chen
Keyword(s):  
Water Stress ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Biochar Amendment

Production, respiration and ammonia excretion of two polychaete species in a north Norfolk saltmarsh

1999 ◽  
Vol 79 (6) ◽  
pp. 1029-1037 ◽  
Author(s):  
Mathilde Nithart ◽  
Elisabeth Alliot ◽  
Chantal Salen-Picard
Keyword(s):  
Oxygen Consumption ◽  
Secondary Production ◽  
Ammonia Excretion ◽  
Sampling Period ◽  
Dry Weight ◽  
Carbon Loss ◽  
Polychaete Species ◽  
Nereis Diversicolor ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen

The secondary production of Nereis diversicolor and Scoloplos armiger (Annelida, Polychaeta) was studied at Stiffkey saltmarshes (north Norfolk coast). Production estimation on the basis of monthly sampling (August 1992–July 1993) gives 17.91 g C m−2 y−1 for N. diversicolor, 3.37 g C m−2 y−1 for S. armiger. Oxygen consumption of individuals was studied using a respirometer at four temperatures (5, 10, 15 and 20°C). At 15 °C, the relationships between O2 consumption (mg h−1) and body dry weight (mg) is Y=0.003X0.695 for S. armiger and Y=0.003X0.498 for N. diversicolor. Ammonia excretion of S. armiger tends to increase with decreasing temperature whereas it increases from 5 to 15 °C for N. diversicolor. Carbon loss through respiration for the sampling period is estimated at 32 g C m−2 y−1 for S. armiger, and 31.7 g C m−2 y−1 for N. diversicolor. About 20% of the potential supply of phytobenthic carbon in the marsh would be converted by the populations of both species. Estimations of carbon and nitrogen budgets of S. armiger are discussed.

Isotopically constrained soil carbon and nitrogen budgets in a soybean field chronosequence in the Brazilian Amazon region

2016 ◽  
Vol 121 (10) ◽  
pp. 2520-2529 ◽  
Author(s):  
Adelaine M. e. Silva Figueira ◽  
Eric A. Davidson ◽  
R. Chelsea Nagy ◽  
Shelby H. Riskin ◽  
Luiz A. Martinelli
Keyword(s):  
Soil Carbon ◽  
Brazilian Amazon ◽  
Amazon Region ◽  
Soybean Field ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Soil Carbon And Nitrogen ◽  
Brazilian Amazon Region
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