The effect of inorganic nitrogen on the added nitrogen interaction of soils in incubation experiments

<p>Soils and sediments in the Lena Delta in Northeast Siberia store large amounts of organic matter including organic bound nitrogen. This nitrogen is not directly available for plants and primary production, but can be remineralised in the soils or in sediments after erosion to the Lena River. Our study aims to estimate the load of reactive nitrogen from terrestrial sources into the Arctic Ocean. Therefore, water and sediment samples were collected along a transect (~200 km) from the centre of the Delta to the open Laptev Sea in summer 2019. On the collected samples, we will measure dissolved organic and inorganic nitrogen, particulate nitrogen and CN ratio. In addition, the <sup>15</sup>N stable isotope values of these components will be determined to identify nitrogen sources, sinks and processes of nitrogen transformation. Additionally, we carried out incubation experiments in the field to determine the potential remineralisation rates of various soil types in Lena water and nutrients fluxes of the sediments. The load of dissolved inorganic nitrogen in the Lena water in the delta was very low and low nitrate and silicate concentration indicate uptake by phytoplankton. Outside the Lena Delta, a lens of nutrient depleted freshwater covered the salty Arctic Ocean water, which had higher loads of reactive nitrogen. The organic matter content of the soils and sediment is highly variable and ranges from 1 to 45 %. This organic matter is the source of reactive nitrogen, which is determined in incubation experiments and using nitrogen stable isotopes. We found that especially the unvegetated soils and sediment are sources of reactive nitrogen in the end of vegetation period, and are potentially sources of nitrous oxide emissions.</p>

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Dynamics of nutrients, total organic carbon, prokaryotes and viruses in onboard incubations of cold-water corals

Biogeosciences ◽

10.5194/bg-8-2609-2011 ◽

2011 ◽

Vol 8 (9) ◽

pp. 2609-2620 ◽

Cited By ~ 16

Author(s):

C. Maier ◽

A. de Kluijver ◽

M. Agis ◽

C. P. D. Brussaard ◽

F. C. van Duyl ◽

...

Keyword(s):

Organic Carbon ◽

Total Organic Carbon ◽

Bottom Water ◽

Cold Water ◽

Inorganic Nitrogen ◽

Inorganic Phosphorus ◽

Lophelia Pertusa ◽

Turnover Rates ◽

Clear Trend ◽

Incubation Experiments

Abstract. The potential influence of the cold-water corals (CWCs) Lophelia pertusa and Madrepora oculata on the dynamics of inorganic nutrient and total organic carbon (TOC) concentrations and the abundances of prokaryotes and viruses in bottom water was assessed in onboard incubation experiments. Ammonium, nitrite, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and TOC concentrations and N:P ratios were typically higher in incubation water with corals than in controls, whereas nitrate concentrations did not reveal a clear trend. Mucus release (normalized to coral surface) was estimated by the net increase rate of TOC concentrations and averaged 23 ± 6 mg C m−2 h−1 for L. pertusa and 21 ± 8 mg C m−2 h−1 for M. oculata. Prokaryotic and viral abundance and turnover rates were typically stimulated in incubation water with corals. This estimated prokaryotic stimulation averaged 6.0 ± 3.0 × 109 cells m−2 h−1 for L. pertusa and 8.4 ± 2.9 × 109 cells m−2 h−1 for M. oculata, whereas the estimated viral stimulation averaged 15.6 ± 12.7 × 109 particles m−2 h−1 for L. pertusa and 4.3 ± 0.4 × 109 particles m−2 h−1 M. oculata. Our data suggest that prokaryotes and viruses are released from corals and that nutrient and mucus release enhanced prokaryotic and viral production. The result of this stimulation could be a fuelling of bottom water in CWC reefs with nutrients and organic matter and consequently an enhancement of microbe-mediated processes.

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Nitrogen uptake capacity of European beech (Fagus sylvatica L.) only partially depends on tree age

Trees ◽

10.1007/s00468-021-02190-z ◽

2021 ◽

Author(s):

Judy Simon ◽

Silvija Bilela ◽

Heinz Rennenberg

Keyword(s):

Inorganic Nitrogen ◽

N Uptake ◽

General Pattern ◽

European Beech ◽

Tree Age ◽

Organic N ◽

Uptake Capacity ◽

Age Classes ◽

Incubation Experiments ◽

N Acquisition

Abstract Key message On calcareous soil, European beech roots prefer organic nitrogen, but only arginine and not glutamine or inorganic nitrogen. Abstract Nitrogen (N) acquisition is a major factor determining the processes and mechanisms involved in tree productivity, development, and competitiveness. However, only few studies have investigated changes in N capturing with tree age. We conducted 15N incubation experiments to quantify inorganic (i.e. ammonium and nitrate) and organic (i.e. glutamine-N and arginine-N) net N acquisition capacity of beech trees of five age classes. Our results showed no general pattern, but that net N uptake capacity was rather N source-specific. Inorganic and glutamine-N uptake did not differ between age classes at all. Arginine-N uptake was highest in the youngest and oldest stands reflecting a high N demand by seedlings for root foraging and biomass production despite low internal N storage capacities and by older trees for storage and reproduction. Organic N was preferred over inorganic N regardless of tree age. Overall, our study shows the high significance of organic N sources for N acquisition in beech trees.

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Dynamics of nutrients, total organic carbon, prokaryotes and viruses in onboard incubations of cold-water corals

Biogeosciences Discussions ◽

10.5194/bgd-8-3829-2011 ◽

2011 ◽

Vol 8 (2) ◽

pp. 3829-3861 ◽

Cited By ~ 2

Author(s):

C. Maier ◽

A. de Kluijver ◽

M. Agis ◽

C. P. D. Brussaard ◽

F. C. van Duyl ◽

...

Keyword(s):

Organic Carbon ◽

Total Organic Carbon ◽

Bottom Water ◽

Cold Water ◽

Inorganic Nitrogen ◽

Inorganic Phosphorus ◽

Lophelia Pertusa ◽

Turnover Rates ◽

Clear Trend ◽

Incubation Experiments

Abstract. The potential influence of the cold-water corals (CWCs) Lophelia pertusa and Madrepora oculata on the dynamics of inorganic nutrient and total organic carbon (TOC) concentrations and the abundances of prokaryotes and viruses in bottom water was assessed in onboard incubation experiments. Ammonium, nitrite, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and TOC concentrations and N:P ratios were typically higher in incubation water with corals than in controls, whereas nitrate concentrations did not reveal a clear trend. Mucus release (normalized to coral surface) was estimated by the net increase rate of TOC concentrations and averaged 23 ± 6 mg C m−2 h−1 for L. pertusa and 21 ± 8 mg C m−2 h−1 for M. oculata. Prokaryotic and viral abundance and turnover rates were typically stimulated in incubation water with corals. This prokaryotic stimulation averaged 6.0 ± 3.0 × 109 cells m−2 h−1 for L. pertusa and 8.4 ± 2.9 ×109 cells m−2 h−1 for M. oculata, whereas the viral stimulation averaged 15.6 ± 12.7 × 109 particles m−2 h−1 for L. pertusa and 4.3 ± 0.4 × 109 particles m−2 h−1 M. oculata. Our data suggest that prokaryotes and viruses are released from corals and that nutrient and mucus release enhanced prokaryotic and viral production. The result of this stimulation could be a fuelling of bottom water in CWC reefs with nutrients and organic matter and consequently an enhancement of microbe-mediated processes.

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Effect of ammonium fixation and displacement on the added nitrogen interaction in incubation experiments

Biology and Fertility of Soils ◽

10.1007/bf00336453 ◽

1994 ◽

Vol 18 (2) ◽

pp. 99-102 ◽

Cited By ~ 6

Author(s):

F. Azam ◽

F. W. Simmons ◽

R. L. Mulvaney

Keyword(s):

Ammonium Fixation ◽

Incubation Experiments ◽

Added Nitrogen Interaction

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Uptake regions of inorganic nitrogen in roots of carob seedlings

Physiologia Plantarum ◽

10.1034/j.1399-3054.1995.950201.x ◽

1995 ◽

Vol 95 (2) ◽

pp. 167-175 ◽

Cited By ~ 1

Author(s):

C. Cruz ◽

S. H. Lips ◽

M. A. Martins-Loucao

Keyword(s):

Inorganic Nitrogen

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ANDROST-5-ENE-3β,17β-DIOL IN OVARY OF POST-MENOPAUSAL HYPEROESTROGENIC WOMEN

Acta Endocrinologica ◽

10.1530/acta.0.0580364 ◽

1968 ◽

Vol 58 (3) ◽

pp. 364-376 ◽

Cited By ~ 5

Author(s):

S. Pesonen ◽

M. Ikonen ◽

B-J. Procopé ◽

A. Saure

Keyword(s):

Ovarian Tissue ◽

Cortical Layer ◽

Vaginal Smears ◽

Incubation Experiments ◽

Cell Groups ◽

Post Menopause ◽

Reducing Activity ◽

Post Menopausal ◽

One Year

ABSTRACT The ovaries of ten patients, at least one year after the post-menopause, were incubated with two Δ5-C19-steroids and also studied histochemically. All these patients had post-menopausal uterine bleeding and increased oestrogen excretion of the urine. The urinary estimations of gonadotrophins, 17-KS, 17-OHCS and pregnanediol were carried out on all patients. Vaginal smears were read according to Papanicolaou, and the endometrium and ovaries were studied histologically. The incubation experiments indicate the presence of Δ5-3β-hydroxysteroid-dehydrogenase. When androst-5-ene-3β,17β-diol was used as precursor the formation of testosterone occurred without any concomitant production of DHA and/or androstenedione. This seems to indicate the possible role of the Δ5-pathway in the formation of testosterone by post-menopausal ovarian tissue. The histochemical reactions indicated a reducing activity on NADH, lactate and glucose-6-phosphate, in certain corpora albicantia, atretic follicles and in diffuse thecoma regions in the cortical layer of the ovary. Steroid-3β-ol-dehydrogenase and β-hydroxybutyrate-dehydrogenase were found only at the edges of certain corpora albicantia, in some individual stroma cell groups and in some atretic follicles. Our studies, both biochemical and histochemical, suggest that the observed increase in the urinary oestrogens of the patients studied might in part at least, be of ovarian origin. This opinion is also supported by the postoperative oestrogen values.

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