scholarly journals Multiple pathways of C and N incorporation by consumers across an experimental gradient of salmon carcasses

Ecosphere ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
P. M. Kiffney ◽  
S. M. Naman ◽  
J. M. Cram ◽  
M. Liermann ◽  
D. G. Burrows
Keyword(s):  
C And N ◽  
N Incorporation ◽  
Salmon Carcasses

scholarly journals Influence of light on particulate organic matter utilization by attached and free-living marine bacteria

2019 ◽  
Author(s):  
Laura Gomez-Consarnau ◽  
David M. Needham ◽  
Peter K. Weber ◽  
Jed A. Fuhrman ◽  
Xavier Mayali
Keyword(s):  
Microbial Community ◽  
Amplicon Sequencing ◽  
Time Of Day ◽  
Rrna Gene ◽  
Free Living ◽  
Isotope Incorporation ◽  
The Pacific ◽  
C And N ◽  
N Incorporation ◽  
The Impact

While the impact of light on primary productivity in aquatic systems has been studied for decades, the role light plays in the degradation of photosynthetically-produced biomass is less well understood. We investigated the patterns of light-induced particle breakdown and bacterial assimilation of detrital C and N using13C and15N labeled freeze-thawed diatom cells incubated in laboratory microcosms with a marine microbial community freshly-collected from the Pacific Ocean. Particles incubated in the dark resulted in increased bacterial counts and dissolved organic carbon concentrations compared to those incubated in the light. Light also influenced the attached and free-living microbial community structure as detected by 16S rRNA gene amplicon sequencing. For example, bacterial taxa from the Sphingobacteriia were enriched on dark-incubated particles and taxa from the family Flavobacteriaceae and the genus Pseudoalteromonas were numerically enriched on particles in the light. Isotope incorporation analysis by phylogenetic microarray and NanoSIMS (a method called Chip-SIP) identified free-living and attached microbial taxa able to incorporate N and C from the particles. Some taxa, including members of the Flavobacteriaceae and Cryomorphaceae, exhibited increased isotope incorporation in the light, suggesting the use of photoheterotrophic metabolisms. In contrast, some members of Oceanospirillales and Rhodospirillales showed decreased isotope incorporation in the light, suggesting that their heterotrophic metabolism, particularly when occurring on particles, might increase at night or may be inhibited by sunlight. These results show that light influences particle degradation and C and N incorporation by attached bacteria, suggesting that the transfer between particulate and free-living phases are likely affected by external factors that change with the light regime, such as time of day, depth and season.

The effects of salmon carcasses on soil nitrogen pools in a riparian forest of southeastern Alaska

2007 ◽  
Vol 37 (7) ◽  
pp. 1194-1202 ◽  
Author(s):  
Scott M. Gende ◽  
Amy E. Miller ◽  
Eran Hood
Keyword(s):  
Temporal Dynamics ◽  
Riparian Forest ◽  
Soil N ◽  
Soil C ◽  
Freshwater Streams ◽  
Spatial And Temporal Dynamics ◽  
Soil C And N ◽  
C And N ◽  
Salmon Carcasses

Long-term studies in Alaska have demonstrated that bears may capture and carry to the riparian forest a large number of salmon that return to spawn in small freshwater streams. Most of the carcasses are partially consumed, resulting in a large amount of salmon nutrients in the form of biomass deposited on the forest floor. Using an experimental approach, we examined how these carcasses may influence the spatial and temporal dynamics of soil C and N in a riparian forest in southeastern Alaska. At their peak, ammonium (NH4+-N) concentrations in soil 10 cm from carcasses were as much as several orders of magnitude greater than soils in adjacent control plots without carcasses and remained elevated until the onset of winter. Nitrate (NO3–-N) and δ15N concentrations also increased coincident with maximum NH4+-N concentrations. However, soil N concentrations were only moderately elevated 20 cm from carcasses and closely resembled background concentrations at 30 cm. These results suggest that salmon carcasses, via bear foraging activities, can dramatically influence soil N pools, although the impacts appear to be highly localized and largely dependent on the spatial distribution of carcasses in the riparian forest.

scholarly journals Use of stable isotopes to measurede novosynthesis and turnover of amino acid-C and -N in mixed micro-organisms from the sheep rumenin vitro

2004 ◽  
Vol 91 (2) ◽  
pp. 253-261 ◽  
Author(s):  
C. Atasoglu ◽  
A. Y. Guliye
Keyword(s):  
Stable Isotopes ◽  
Amino Acid ◽  
Protein Hydrolysate ◽  
Rumen Fluid ◽  
Deconvolution Analysis ◽  
C And N ◽  
N Incorporation ◽  
Isoleucine Metabolism ◽  
Micro Organisms

Protein synthesis and turnover in ruminal micro-organisms were assessed by stable-isotope methods in order to follow independently the fate of amino acid (AA)-C and -N in different AA. Rumen fluid taken from sheep receiving a grass hay–concentrate diet were strained and incubatedin vitrowith starch–cellobiose–xylose in the presence of NH3and 5 g algal protein hydrolysate (APH)/l, in incubations where the labels were15NH3, [15N]APH or [13C]APH. Total15N incorporation was calculated from separate incubations with15NH3and [15N]APH, and net N synthesis from the increase in AA in protein-bound material. The large difference between total and net AA synthesis indicated that substantial turnover of microbial protein occurred, averaging 3·5 %/h. Soluble AA-N was incorporated on average more extensively than soluble AA-C (70v.50 % respectively,P=0·001); however, incorporation of individual AA varied. Ninety percent of phenylalanine-C was derived from the C-skeleton of soluble AA, whereas the incorporation of phenylalanine-N was 72 %. In contrast, only 15 % aspartate-C + asparagine-C was incorporated, while 45 % aspartate-N+asparagine-N was incorporated. Deconvolution analysis of mass spectra indicated substantial exchange of carboxyl groups in several AA before incorporation and a condensation of unidentified C2and C4intermediates during isoleucine metabolism. The present results demonstrate that differential labelling with stable isotopes is a way in which fluxes of AA synthesis and degradation, their biosynthetic routes, and separate fates of AA-C and -N can be determined in a mixed microbial population.

STABILIZATION OF RESIDUAL C AND N IN SOIL

1988 ◽  
Vol 68 (4) ◽  
pp. 733-745 ◽  
Author(s):  
R. A. JANZEN ◽  
C. F. SHAYKEWICH ◽  
TEE BOON GOH
Keyword(s):  
Wheat Straw ◽  
Clay Soil ◽  
Organic Matter Content ◽  
Matter Content ◽  
Red River ◽  
Residue Management ◽  
Plant Residue ◽  
Fertilizer Treatment ◽  
C And N ◽  
N Incorporation

Three Manitoba soils varying in clay and organic matter content were mixed with each of four plant residue amendments: (1) a control where no plant or fertilizer materials were added; (2) 14C- and 15N-labelled wheat straw; (3) 14C- and 15N-labelled wheat straw plus 15N-labelled KNO3; and (4) 14C- and 15N-labelled prebloom alfalfa residue. The soils were incubated at 20 °C and 75% field capacity for 90 d. Soil samples were collected at 0, 7, 30, and 90 d of incubation. Two humic acid fractions were obtained from the amended soils. Fraction A was obtained by Na4P2O7 extraction and Fraction B was recovered from the remaining residue by sonication. Significant (P < 0.05) differences were observed in the incorporation of 14C and 15N into both fractions. The effect of clay content on C and N incorporation was most marked in Fraction B: C incorporation in all treatments tended to be higher in the Red River Clay soil than in the Newdale (bottom of the knoll) soil; N incorporation in the straw and alfalfa treatments tended to be higher in the Red River Clay soil but, in the straw-plus-fertilizer treatment, N incorporation tended to be higher in the Newdale (bottom of the knoll) soil. The effect of the form of C and N in the residue was most apparent in the incorporation of N into Fraction B: in all soils the level of 15N in the alfalfa treatment was significantly (P < 0.05) higher than that in the straw plus fertilizer treatment. Key words: Plant residue management, incorporation, incubation, C and N turnover, KNO3 fertilizer

Denitrification in a Carbon and Nitrogen Removal System for Leachate Treatment: Performance of a Upflow Sludge Blanket (USB) Reactor

1999 ◽  
Vol 40 (8) ◽  
pp. 145-151 ◽  
Author(s):  
Liliana Borzacconi ◽  
Gisela Ottonello ◽  
Elena Castelló ◽  
Heber Pelaez ◽  
Augusto Gazzola ◽  
...  
Keyword(s):  
Complete System ◽  
Carbon Sources ◽  
Uasb Reactor ◽  
Leachate Treatment ◽  
N Removal ◽  
Start Up ◽  
Aerobic Reactor ◽  
C And N ◽  
Reactor Operating ◽  
Removal System

The performance of a bench scale upflow sludge bed (USB) denitrifying reactor was evaluated in order to integrate it into a C and N removal system for Sanitary Landfill Leachate. The raw leachate used presented COD and NH4-N average values of 30000 mg/l and 1000 mg/l, respectively. The complete system comprises in addition an UASB reactor and a nitrifying RBC. A portion of the aerobic reactor effluent was recycled into the denitrification stage and some raw leachate was also added as an additional C source. In order to obtain operating parameters the denitrifying reactor was operated alone. Sludge from an aerobic reactor (RBC) treating raw leachate was used as inoculum. Shortly after the start up, good granulation of the sludge bed was observed. Using raw leachate and UASB outlet as carbon sources with COD/NO3-N ratios of 4 and 12, respectively, denitrification efficiencies of about 90% were reached. A sludge yield of 0.16 gVSS/gCODremoved was obtained operating with raw leachate. For the anoxic reactor operating in the complete system, denitrification efficiencies of 90% were also achieved. A nitrogen gas recycle was a successful way to avoid frequently observed sludge bed rising problems.

SOIL C AND N AS INDICATORS OF VINEYARD SOIL QUALITY IN THE RAVNI KOTARI REGION OF CROATIA

2020 ◽  
Author(s):  
Sonia C. Clemens ◽  
◽  
Mia Brkljaca ◽  
Delaina Pearson ◽  
C. Brannon Andersen
Keyword(s):  
Soil Quality ◽  
Soil C ◽  
Vineyard Soil ◽  
Soil C And N ◽  
C And N

scholarly journals Forest defoliator pests alter carbon and nitrogen cycles

2016 ◽  
Vol 3 (10) ◽  
pp. 160361 ◽  
Author(s):  
Anne l-M-Arnold ◽  
Maren Grüning ◽  
Judy Simon ◽  
Annett-Barbara Reinhardt ◽  
Norbert Lamersdorf ◽  
...  
Keyword(s):  
Climate Change ◽  
Leaf Litter ◽  
Soil Microbial Activity ◽  
Quercus Petraea ◽  
Oak Forests ◽  
Operophtera Brumata ◽  
Winter Moth ◽  
Carbon And Nitrogen ◽  
Soil Microbial ◽  
C And N

Climate change may foster pest epidemics in forests, and thereby the fluxes of elements that are indicators of ecosystem functioning. We examined compounds of carbon (C) and nitrogen (N) in insect faeces, leaf litter, throughfall and analysed the soils of deciduous oak forests ( Quercus petraea  L.) that were heavily infested by the leaf herbivores winter moth ( Operophtera brumata  L.) and mottled umber ( Erannis defoliaria  L.). In infested forests, total net canopy-to-soil fluxes of C and N deriving from insect faeces, leaf litter and throughfall were 30- and 18-fold higher compared with uninfested oak forests, with 4333 kg C ha −1 and 319 kg N ha −1 , respectively, during a pest outbreak over 3 years. In infested forests, C and N levels in soil solutions were enhanced and C/N ratios in humus layers were reduced indicating an extended canopy-to-soil element pathway compared with the non-infested forests. In a microcosm incubation experiment, soil treatments with insect faeces showed 16-fold higher fluxes of carbon dioxide and 10-fold higher fluxes of dissolved organic carbon compared with soil treatments without added insect faeces (control). Thus, the deposition of high rates of nitrogen and rapidly decomposable carbon compounds in the course of forest pest epidemics appears to stimulate soil microbial activity (i.e. heterotrophic respiration), and therefore, may represent an important mechanism by which climate change can initiate a carbon cycle feedback.

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