scholarly journals Understanding carbon regulation in aquatic systems - Bacteriophages as a model

F1000Research ◽  
2015 ◽  
Vol 4 ◽  
pp. 138 ◽  
Author(s):  
Swapnil Sanmukh ◽  
Krishna Khairnar ◽  
Waman Paunikar ◽  
Satish Lokhande

The bacteria and their phages are the most abundant constituents of the aquatic environment, and so represent an ideal model for studying carbon regulation in an aquatic system. The microbe-mediated interconversion of bioavailable organic carbon (OC) into dissolved organic carbon (DOC) by the microbial carbon pump (MCP) has been suggested to have the potential to revolutionize our view of carbon sequestration. It is estimated that DOC is the largest pool of organic matter in the ocean and, though a major component of the global carbon cycle, its source is not yet well understood. A key element of the carbon cycle is the microbial conversion of DOC into inedible forms. The primary aim of this study is to understand the phage conversion from organic to inorganic carbon during phage-host interactions.Time studies of phage-host interactions under controlled conditions reveal their impact on the total carbon content of the samples and their interconversion of organic and inorganic carbon compared to control samples. A total organic carbon (TOC) analysis showed an increase in inorganic carbon content by 15-25 percent in samples with bacteria and phage compared to samples with bacteria alone. Compared to control samples, the increase in inorganic carbon content was 60-70-fold in samples with bacteria and phage, and 50-55-fold for samples with bacteria alone. This study indicates the potential impact of phages in regulating the carbon cycle of aquatic systems.

2010 ◽  
Vol 8 (5) ◽  
pp. 196-201 ◽  
Author(s):  
Stuart Findlay ◽  
William H. McDowell ◽  
David Fischer ◽  
Michael L. Pace ◽  
Nina Caraco ◽  
...  

Soil Research ◽  
2003 ◽  
Vol 41 (5) ◽  
pp. 889 ◽  
Author(s):  
T. A. Knowles ◽  
B. Singh

Soil carbon is an important component of the global carbon cycle with an estimated pool of soil organic carbon of about 1500 Gt. There are few estimates of the pool of inorganic carbon, but it is thought to be approximately 50% of the organic carbon pool. There is no detailed study on the estimation of the soil carbon pool for Australian soils.In order to quantify the carbon pools and to determine the extent of spatial variability in the organic and inorganic carbon pools, 120 soil cores were taken down to a depth of 0.90 m from a typical cotton field in northern NSW. Three cores were also taken from nearby virgin bushland and these samples were used as paired samples. Each soil core was separated into 4 samples, i.e. 0–0.15, 0.15–0.30, 0.30–0.60, and 0.60–0.90 m. Soil organic carbon was determined by wet oxidation and inorganic carbon content was determined using the difference between total carbon and organic carbon, and confirmed by the acid dissolution method. Total carbon was measured using a LECO CHN analyser. Soil organic carbon of the field constituted 62% (0–0.15 m), 58% (0.15–0.30 m), 60% (0.30–0.60 m), and 67% (0.60–0.90 m) of the total soil carbon. The proportion of inorganic carbon in total carbon is higher than the global average of 32%. Organic carbon content was relatively higher in the deeper layers (>0.30�m) of the studied soils (Vertosols) compared with other soil types of Australia. The carbon content varied across the field, however, there was little correlation between the soil types (grey, red, or intergrade colour) and carbon content. The total soil carbon pool of the studied field was estimated to be about 78 t/ha for 0–0.90 m layer, which was approximately 58% of the total soil carbon in the soil under nearby remnant bushland (136 t/ha). The total pool of carbon in the cotton soils of NSW was estimated to be 44.8 Mt C, where organic carbon and inorganic carbon constitute 34.9 Mt C and 9.9 Mt C, respectively. Based on the results of a limited number of paired sites under remnant vegetation, it was estimated that about 18.9 Mt of C has been lost from Vertosols by cotton cropping in NSW. With more sustainable management practices such as conservation tillage and green manuring, some of the lost carbon can be resequestered, which will help to mitigate the greenhouse effect, improve soil quality and may increase crop yield.


Author(s):  
Andrei Shepelev ◽  
Alexander Kizyakov ◽  
Sebastian Wetterich ◽  
Alexandra Cherepanova ◽  
Thomas Opel ◽  
...  

The most massive and fast-eroding thaw slump of the Northern Hemisphere located in the Yana uplands of northern Yakutia was investigated to assess in detail the cryogenic inventory and carbon pools of two distinctive Ice Complex stratigraphic units and the uppermost cover deposits. Differentiating into modern and Holocene near-surface layers (active layer and shielding layer), highest total carbon contents were found in the active layer (18.7 kg m-2), while the shielding layer yielded much lower carbon content of 1.8 kg m-2. The late Pleistocene upper Ice Complex contained 10.4 kg m-2 total carbon, and the mid-Pleistocene lower Ice Complex 17.7 kg m-2. The proportion of organic carbon from total carbon content is well above 70% in all studied units with 94 % in the active layer, 73% in the shielding layer, 83% in the upper Ice Complex and 79% in the lower Ice Complex. Inorganic carbon is low in the overall structure of the deposits.


Author(s):  
Enrico MANCINELLI ◽  
Edita BALTRĖNAITĖ ◽  
Pranas BALTRĖNAS ◽  
Eglė MARČIULAITIENĖ ◽  
Giorgio PASSERINI

Dissolved organic carbon (DOC) interacts with dissolved trace metal affecting their mobility and bioavailability through the formation of DOC–metal complexes. Several types of biochar (BC) produced from slow pyrolysis of wood chips (WC), lignin (LG), and digested sewage sludge at 450 and 700 °C were tested for DOC leaching via batch and up-flow percolation test methods. Trace metal (Cd, Cu, and Pb) speciation modelling in BC eluates was carried out combining measured data (i.e., DOC, ph, temperature, and dissolved trace metal concentrations) with data reported in the literature regarding fractions of DOC that are inert or active (i.e., fulvic acids (FA) and humic acids (HA)) in metal binding. BC from LG (BCLG) and WC (BCWC) at 700 °C released lower cumulative amounts of DOC compared with BC at 450 °C in the range 0.02–0.07% and 0.06–0.09% of total carbon content, respectively. For both pyrolysis temperatures, BCWC exhibited a higher tendency to release DOC compared to BCLG. Speciation modelling results showed the predominance of FA and HA complexes of Cd, Cu, and Pb in all the eluates from BCWC and BCLG irrespective of the inert fractions of DOC or the different fractions of active FA and HA considered.


Land ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 305
Author(s):  
Andrei G. Shepelev ◽  
Alexander Kizyakov ◽  
Sebastian Wetterich ◽  
Alexandra Cherepanova ◽  
Alexander Fedorov ◽  
...  

The most massive and fast-eroding thaw slump of the Northern Hemisphere located in the Yana Uplands of Northern Yakutia was investigated to assess in detail the cryogenic inventory and carbon pools of two distinctive Ice Complex stratigraphic units and the uppermost cover deposits. Differentiating into modern and Holocene near-surface layers (active layer and shielding layer), highest total carbon contents were found in the active layer (18.72 kg m−2), while the shielding layer yielded a much lower carbon content of 1.81 kg m−2. The late Pleistocene upper Ice Complex contained 10.34 kg m−2 total carbon, and the mid-Pleistocene lower Ice Complex 17.66 kg m−2. The proportion of organic carbon from total carbon content is well above 70% in all studied units with 94% in the active layer, 73% in the shielding layer, 83% in the upper Ice Complex and 79% in the lower Ice Complex. Inorganic carbon is low in the overall structure of the deposits.


1999 ◽  
Vol 79 (2) ◽  
pp. 303-310 ◽  
Author(s):  
F. L. Wang ◽  
A. K. Alva

Leaching of water soluble soil carbon plays an important role in downward transport of soil nutrients and pollutants and may be influenced by soil and management factors. We examined the leaching of water soluble carbon from two sandy soils under nitrogen fertilization by adapting an intermittent leaching-incubation technique using packed soil columns (94 × 10 cm). After 30 d, cumulative amounts of water-soluble organic carbon (SOC) leached from the Candler and Wabasso sand for various treatments in mg C column−1 were: 77 and 302 (NH4NO3), 64 and 265 (control), and 45 and 239 (isobutylidene diurea, IBDU), respectively. The IBDU and NH4NO3 treatments increased the leaching of water-soluble inorganic carbon (SIC), which ranged from 2 to 38 mg C column−1 over 30 d. At the end of eight cycles of leaching/incubation, the total carbon content increased at depth (control and NH4NO3 treatment) in the Candler sand, but decreased in the Wabasso sand. In the first leaching event, the average rate of SOC leaching from the Wabasso sand was 26 mg C column−1 d−1 which dropped rapidly to about 5 mg C column−1 d−1 towards the end of the experiment. The rate of SOC leaching from the Candler sand was much lower (<8 mg C column−1 d−1) than the rate of SOC leaching from the Wabasso sand. Compared with the unamended treatments, application of NH4NO3 increased and IBDU decreased the leaching of SOC in both soils. These effects of N application were considerable during the initial two to three leaching events only. Our results suggest that the initial rainfalls that follow a dry period may be critical for transporting SOC from the upper layer of these sandy soils. Key words: C leaching, sandy soil, intermittent leaching condition, isobutylidene


1964 ◽  
Vol 44 (2) ◽  
pp. 232-236 ◽  
Author(s):  
J. F. Dormaar

Two orthic profiles, widely separated geographically, of each of four parent materials—lacustrine, alluvial–lacustrine, glacial till, and Aeolian—were selected at undisturbed sites within each of the Brown, Dark Brown, and Thin Black soil zones. Material from the Ah and Bm horizons was subjected to solvent extraction, and for each sample the total organic carbon of seven different fractions was determined.The efficiency of the procedure in extracting humus carbon decreased as the total carbon content of the soil increased. Total organic matter, the first humic acid fraction, and the combined total of the three humic acid fractions showed significant differences between soil zones. The only significant separation between all four parent materials was made by the alcohol-benzene fraction. Other parent material separations were possible only following the summation of data of several fractions, such as the three humic acid fractions or the two fulvic acid fractions. A simplification of the procedure in case of soils of one Order and a modification to overcome the impeding effect of increased carbon content are requisite.


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