Repeated freeze–thaw cycles increase extractable, but not total, carbon and nitrogen in a Maine coniferous soil

Geoderma ◽  
2021 ◽  
Vol 402 ◽  
pp. 115353
Author(s):  
Kaizad F. Patel ◽  
Corianne Tatariw ◽  
Jean D. MacRae ◽  
Tsutomu Ohno ◽  
Sarah J. Nelson ◽  
...  
Keyword(s):  
Total Carbon ◽  
Carbon And Nitrogen ◽  
Freeze Thaw

scholarly journals First in situ estimations of small phytoplankton carbon and nitrogen uptake rates in the Kara, Laptev, and East Siberian seas

2018 ◽  
Author(s):  
Bhavya P. Sadanandan ◽  
Jang Han Lee ◽  
Ho Won Lee ◽  
Jae Joong Kaang ◽  
Jae Hyung Lee ◽  
...  
Keyword(s):  
Sea Ice ◽  
Nitrogen Uptake ◽  
N Uptake ◽  
Total Carbon ◽  
The Arctic ◽  
Carbon And Nitrogen ◽  
Uptake Rates ◽  
Wide Range ◽  
Small Phytoplankton

Abstract. Carbon and nitrogen uptake rates by small phytoplankton (0.7–5 μm) in the Kara, Laptev, and East Siberian seas in the Arctic Ocean were quantified using in situ isotope labelling experiments for the first time as part of the NABOS (Nansen and Amundsen Basins Observational System) program during August 21 to September 22, 2013. The depth integrated C, NO3−, and NH4+ uptake rates by small phytoplankton showed a wide range from 0.54 to 15.96 mg C m−2 h−1, 0.05 to 1.02 and 0.11 to 3.73 mg N m−2 h−1, respectively. The contributions of small phytoplankton towards the total C, NO3−, and NH4+ was varied from 24 to 89 %, 32 to 89 %, and 28 to 89 %, respectively. The turnover times for NO3− and NH4+ by small phytoplankton during the present study point towards the longer residence times (years) of the nutrients in the deeper waters, particularly for NO3−. Relatively, higher C and N uptake rates by small phytoplankton obtained during the present study at locations with less sea ice concentrations points towards the possibility of small phytoplankton thrive under sea ice retreat under warming conditions. The high contributions of small phytoplankton towards the total carbon and nitrogen uptake rates suggest capability of small size autotrophs to withstand in the adverse hydrographic conditions introduced by climate change.

Total carbon and nitrogen stocks under different land use/land cover types in the Southwestern region of Nigeria

2020 ◽  
Vol 22 ◽  
pp. e00320
Author(s):  
Idowu Ezekiel Olorunfemi ◽  
Johnson Toyin Fasinmirin ◽  
Ayorinde Akinlabi Olufayo ◽  
Akinola Adesuji Komolafe
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Total Carbon ◽  
Land Use Land Cover ◽  
Land Cover Types ◽  
Carbon And Nitrogen ◽  
Carbon And Nitrogen Stocks

Long-term effects of harvest residue management on soil total carbon and nitrogen concentrations of a replanted Chinese fir plantation

2013 ◽  
Vol 33 (13) ◽  
pp. 4205-4213
Author(s):  
胡振宏 HU Zhenhong ◽  
何宗明 HE Zongming ◽  
范少辉 FAN Shaohui ◽  
黄志群 HUANG Zhiqun ◽  
万晓华 WAN Xiaohua ◽  
...  
Keyword(s):  
Chinese Fir ◽  
Residue Management ◽  
Total Carbon ◽  
Long Term Effects ◽  
Carbon And Nitrogen ◽  
Nitrogen Concentrations ◽  
Chinese Fir Plantation ◽  
Harvest Residue

Age-related differential catabolism in the snail, Viviparus georgianus, and its significance in the bioenergetics of sexual dimorphism

1986 ◽  
Vol 64 (2) ◽  
pp. 340-346 ◽  
Author(s):  
David W. Aldridge ◽  
W. D. Russell-Hunter ◽  
Daniel E. Buckley
Keyword(s):  
Sexual Dimorphism ◽  
High Protein Diet ◽  
Protein Diet ◽  
Total Carbon ◽  
Age Group ◽  
Carbon And Nitrogen ◽  
Age Related ◽  
Lower Protein ◽  
Carbon Intake ◽  
Viviparus Georgianus

Catabolic partitioning of carbon and nitrogen was investigated to clarify the sexual dimorphism of bioenergetics in Viviparus georgianus. Experiments involved summer stocks of 3-, 15-, 27-, and 39-month-old male and female snails grazing on an artificial high protein diet and, for 15-month snails only, comparison tests using a lower protein diet. Per snail ingestion and partitioning rates and growth are generally maximal for 15-month snails and decline with age in both sexes. In each age group, females have lower rates for weight-specific ingestion of protein carbon and nonprotein carbon than males. For protein carbon, females also show lower rates of catabolism. Compensation for the lower protein diet is more marked in females, which increase total carbon intake by 58% and reduce catabolic use of protein carbon by 40% (against a male reduction of 25%). When discussing evolutionary problems in terms of actuarial bioenergetics, quantification of both physiological rates and ecological efficiencies can be of value in a broadly adaptational approach.

Effects of freeze-thaw on aggregate stability and the organic carbon and nitrogen enrichment ratios in aggregate fractions

2014 ◽  
Vol 30 (4) ◽  
pp. 507-516 ◽  
Author(s):  
Y. J. Chai ◽  
X. B. Zeng ◽  
S. Z. E ◽  
L. Y. Bai ◽  
S. M. Su ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Aggregate Stability ◽  
Nitrogen Enrichment ◽  
Carbon And Nitrogen ◽  
Freeze Thaw ◽  
Aggregate Fractions

scholarly journals Effects of Low Temperature and Freeze-Thaw Cycles on Hydrocarbon Biodegradation in Arctic Tundra Soil

2001 ◽  
Vol 67 (11) ◽  
pp. 5107-5112 ◽  
Author(s):  
Mikael Eriksson ◽  
Jong-Ok Ka ◽  
William W. Mohn
Keyword(s):  
Carbon Dioxide ◽  
Arctic Tundra ◽  
Carbon Dioxide Production ◽  
Additional Treatment ◽  
Total Carbon ◽  
Hydrocarbon Biodegradation ◽  
Tundra Soil ◽  
Spacer Length ◽  
Freeze Thaw ◽  
Arctic Tundra Soil

ABSTRACT Degradation of petroleum hydrocarbons was monitored in microcosms with diesel fuel-contaminated Arctic tundra soil incubated for 48 days at low temperatures (−5, 0, and 7°C). An additional treatment was incubation for alternating 24-h periods at 7 and −5°C. Hydrocarbons were biodegraded at or above 0°C, and freeze-thaw cycles may have actually stimulated hydrocarbon biodegradation. Total petroleum hydrocarbon (TPH) removal over 48 days in the 7, 0, and 7 and −5°C treatments, respectively, was 450, 300, and 600 μg/g of soil. No TPH removal was observed at −5°C. Total carbon dioxide production suggested that TPH removal was due to biological mineralization. Bacterial metabolic activity, indicated by RNA/DNA ratios, was higher in the middle of the experiment (day 21) than at the start, in agreement with measured hydrocarbon removal and carbon dioxide production activities. The total numbers of culturable heterotrophs and of hydrocarbon degraders did not change significantly over the 48 days of incubation in any of the treatments. At the end of the experiment, bacterial community structure, evaluated by ribosomal intergenic spacer length analysis, was very similar in all of the treatments but the alternating 7 and −5°C treatment.

scholarly journals Accelerating the spin-up of the coupled carbon and nitrogen cycle model in CLM4

2014 ◽  
Vol 7 (6) ◽  
pp. 9109-9132
Author(s):  
Y. Fang ◽  
C. Liu ◽  
L. R. Leung
Keyword(s):  
Computation Time ◽  
Fire Disturbance ◽  
Total Carbon ◽  
Saturated Porous Media ◽  
Convergence Criteria ◽  
Atmospheric Forcing ◽  
Carbon And Nitrogen ◽  
Community Land Model ◽  
The Common ◽  
Simulation Time

Abstract. The commonly adopted biogeochemistry spin-up process in earth system model is to run the model for hundreds to thousands of years subject to periodic atmospheric forcing to reach dynamic steady state of the carbon-nitrogen (CN) models. A variety of approaches have been proposed to reduce the computation time of the spin-up process. Significant improvement in computational efficiency has been made recently. However, a long simulation time is still required to reach the common convergence criteria of the coupled carbon/nitrogen model. A gradient projection method was proposed and used to further reduce the computation time after examining the trend of the dominant carbon pools. The Community Land Model version 4 (CLM4) with carbon and nitrogen component was used in this study. From point scale simulations we found that the method can reduce the computation time by 20–69% compared to the fastest approach in the literature. We also found that the cyclic stability of total carbon for some cases differs from that of the periodic atmospheric forcing, and some cases even showed instability. Close examination showed that one case has a carbon periodicity much longer than that of the atmospheric forcing due to the annual fire disturbance that is longer than half a year. The rest was caused by the instability of water table calculation in the hydrology model of CLM4. The instability issue is resolved after we replaced the hydrology scheme in CLM4 with a low model for variably saturated porous media.

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