Total CO2 Evolution Research Articles

Effect of Industrial Byproducts Containing High Aluminum or Iron Levels on Plant Residue Decomposition

Excess phosphorus (P) in soils is a result of manure and fertilizer additions that exceeded crop P requirements. Reducing or eliminating future P fertilizer additions or manures is one method of remediation. Another would be to treat manures or soils with byproducts that contain iron (Fe), aluminum (Al), or calcium (Ca) that adsorb P readily. A study was conducted in which two industrial byproducts and 14C-labeled soybean leaves and stems were added to two soils and soil organic matter and residue decomposition were monitored. Water treatment residue (WTR) containing high Al content and iron-rich residue (IRR) were added to Sassafras and Matapeake soils at rates from 0.5 to 10.0 g kg−1 soil. Lime (CaO) was added as a treatment to determine the effect of increased pH. Additions of WTR to either soil did not affect decomposition of 14C-labeled soybean leaves and stems, soil organic matter decomposition recorded by total CO2 evolution or residual soil 14C. Addition of IRR affected decomposition of 14C-labeled soybean leaves and stems, soil organic matter decomposition recorded by total CO2 and residual soil 14C. Although no one factor explained the effects on decomposition, salinity may be a factor as well as pH. Lime addition corrected the low soil organic matter decomposition as a result of the 10 g kg−1 IRR amendment. Lime also reduced salinity about 20%. Remediation of high P soils or treatment of manure is beneficial, but additional tests on biological effects on industrial byproduct addition may be necessary.

Effects of a nonionic surfactant on biodegradation of phenanthrene and hexadecane in soil

AbstractThe influence of a nonionic (alcohol ethoxylate) surfactant (Witconol SN70) on biodegradation of phenanthrene and hexadecane (nonaqueous‐phase liquid) in soil was studied in batch and transport systems. Simultaneous enhancement of phenanthrene and hexadecane degradation was noted at surfactant doses resulting in aqueous‐phase surfactant concentrations below the critical micelle concentration (CMC). Conversely, degradation rates of both compounds declined to essentially zero at supra‐CMC doses, suggesting that distinct mechanisms of inhibition and enhancement were operating depending on the effective surfactant concentration (i.e., accounting for surfactant sorption, log KD = 2.2 L/kg). Surfactant doses resulting in enhanced degradation correlated with enhanced gross microbial activity as determined using total CO2 evolution rates. Supra‐CMC doses that resulted in inhibited degradation did not suppress gross microbial activity. Furthermore, measurements of phenanthrene solubilization and surface tension indicated that phenanthrene was solubilized at supra‐CMC levels of surfactant. Mechanisms of inhibition of phenanthrene and hexadecane degradation at supra‐CMC surfactant concentrations may include changes in interfacial chemistry and subsequent mass transfer processes due to sorbed surfactant, reduced bioavailability of micelle‐bound phenanthrene and hexadecane, or inhibition of specific members of the microbial community responsible for hydrophobic organic compound degradation.

The influence of acid irrigation and liming on the soil microbial biomass in a Norway spruce (Picea abies [L.] K.) stand

Over a period of three years (1990–1992) microbial biomass-C (Cmic), CO2 evolution, the Cmic:Corg ratio and the metabolic quotient for CO2 (qCO2) were determined in a Norway spruce stand (Hoglwald) with experimentally acid-irrigated and limed plots since 1984. A clear relationship between soil pH and the level of microbial biomass-(Cmic) was noted, Cmic increasing with increasing soil pH in Oh or Ah horizons. More microbial biomass-C per unit C{org} (Cmic:Corg ratio) was detected in limed plots with elevated pH of Oh or Ah horizons as compared to unlimed plots with almost 3 times more Cmic per unit Corg in the limed Oh horizon. Differences here are significant at least at the p=0.05 level. The positive effects of liming (higher pH) on the Cmic:Corg ratio was more pronounced in the upper horizon (Oh)). The total CO2 evolution rate of unlimed plots was only half of that noted for limed plots which corresponded to the low microbial biomass levels of unlimed plots. The specific respiratory activity, qCO2, was similar and not significantly different between the unlimed control plot and the limed plot. Acid irrigation of plots with already low pH did not significantly affect the level of microbial biomass, the Cmic:Corg ratio or qCO2. An elevated qCO2 could be seen, however, for the limed + acid irrigated plot. The biomass seemed extremely stressed, showing with 3.8 µg CO2-C mg-1 Cmic h-1 (Oh) the highest qCO2 value of all treatments. This was interpreted as a reflection of the continuous adaptation processes to the H+ ions by the microflora. The negative effect of acid irrigation of limed plots was also manifested in a decreased Cmic:Corg ratio.

Interactions in microbial use of soluble plant components in soil

Glucose, glutamic acid, alanine, valine, and albumin were used as model substances to represent readily available soluble plant components. Their mineralisation in soil was monitored by making hourly measurements of total CO2 evolution and periodic measurements of 14CO2 during a 5-day incubation period. When glucose and the amino acids were combined in dual substrates the two components were mineralised simultaneously. In each combination the component with the shortest lag phase or highest specific growth rate (μ) was mineralised preferentially. Glucose accelerated the mineralisation of the amino acids that had longer lag phases than glucose (i.e., alamine and valine). During the first 8 h, glucose mineralisation was reduced in the dual substrates compared with its mineralisation as a single substrate. The smaller the difference between the lag phase of glucose and the amino acid, the greater was the reduction in the glucose mineralisation rate. During the exponential phase, the effects on glucose mineralisation were dependent on the nature and concentration of the amino acid. The interactions observed between glucose and amino acid decomposition indicated that these substances were mineralised, at least partly, by the same microorganisms. In contrast, glucose and the soluble protein albumin were decomposed independently of each other.

Strain selection, medium development and scale-up of toyocamycin production by streptomyces chrestomyceticus

The batch productivity (QTM) of the production of the nucleoside antibiotic toyocamycin (TM) by Streptomyces chrestomyceticus was increased ten-fold by selection of a UV generated mutant, optimization of pH, increasing incubation temperature from 28 °C to 36 °C, and addition of soy oil. Initial high oxygen transfer rates stimulated QTM maxima two-fold. Antibiotic production by the mutant strain, U190, however, appeared more shear sensitive than the parent culture FCRF 341 with maximum antibiotic titer being inversely related to impellor tip velocity, Tv. For this reason, scale-up could not be done at constant P/V or constant volumetric oxygen transfer. Instead, programming of impeller speed was evaluated in order to maintain optimal impeller tip velocity during scale-up. It was found that a low constant Tv maintained in scale-up in geometrically similar vessels was most beneficial for duplication of optimal antibiotic productivity, QTM. Pilot fermentations (120 dm3 scale) were used to determine coefficients of QTM variation from oxygen uptake rate (OUR) and total CO2 evolution data for monitoring of QTM variation during scale-up to the 12,000 dm3 scale. This technique allowed for on-line prediction of antibiotic titer and QTM from fermentor exhaust gas data.

Biodegradation of four triaryl/alkyl phosphate esters in sediment under various temperature and redox conditions∗

The distribution and fate of four 14C‐ring‐labelled triaryl/alkyl phosphate esters (2‐ethylhexyl‐diphenyl phosphate (EHDP), t‐butylphenyldiphenyl phosphate (tBPDP), tri‐m‐cresyl phosphate (mTCP) and triphenyl phosphate (TPP)) were compared at 25,10 and 2°C in pond and river sediments (sediment : water ratio 1: 10). Half‐lives in sediment ranged from 2.8 days for TPP to 5.3 days for EHDP at 25°C and from 11.9 to 19.1 days for the same compounds at 2°C. Incubation of the four compounds in sediment (25°C) under air or nitrogen purge had little influence on the rate of degradation of the compounds. Total CO2 evolution ranged from 4% for EHDP to 21% from mTCP and was similar in sediments under air and nitrogen purge (redox potentials +362 to — 51mV). Radioactivity extractable from sediment consisted mainly of intact phosphate esters and small amounts of more polar products ( < 10 % of total 14C) which could be separated from the intact esters by reverse‐phase TLC and HPLC. Diaryl phosphates were minor degradat...

Effect of chromate and organic amendments on the composition and activity of the microorganism flora in soil

Abstract The effects of chromate and organic amendments on the composition and activity of the microbial flora in a soil were studied after the addition of rice straw and cow manure to a soil which was treated with Na2CrO4. At a 20 ppm level of chromate, CO2 evolution was reduced and at a 100 ppm chromate level it was markedly depressed. Cow manure as a compost promoted the activity and multiplication of the microorganisms, and accelerated the decomposition of rice straw, and after 20 days the total CO2 evolution increased 1.3–1.4 times compared with that in a soil which contained only rice straw. By the addition of 100 ppm chromate, the population of the fungi increased. It is assumed that the numbers of fungi sensitive to chromate decreased, which promoted the growth of the fungi tolerant to chromate. The bacterial number in the Cr-treated soils remained as high as that in the untreated soils, and the tolerant bacteria were considered to be dominant. As a whole it appeared that the fungi were more tolerant to chromate than the bacteria. In contrast, the population of actinomycetes decreased to less than 104 per g soil by the addition of 100 ppm chromate, and all the species of actinomycetes were considered to be sensitive to chromate. The reduction of chromate from the hexavalent form to the trivalent form was promoted by the addition of rice straw or cow manure and further accelerated by the addition of both materials because the microbial activity was stimulated.

Nitrogen Dynamics in Stream Wood Samples Incubated with [ 14 C]Lignocellulose and Potassium [ 15 N]Nitrate

Surface wood samples obtained from a Douglas fir log (Pseudotsuga menziesii) in a Pacific Northwest stream were incubated in vitro with [C]lignocellulose in a defined mineral salts medium supplemented with 10 mg of N liter of N-labeled NO(3) (50 atom% N). Evolution of CO(2), distribution and isotopic dilution of N, filtrate N concentrations, and the rates of denitrification, N(2) fixation, and respiration were measured at 6, 12, and 18 days of incubation. The organic N content of the lignocellulose-wood sample mixture had increased from 132 mug of N to a maximum of 231 mug of N per treatment after 6 days of incubation. Rates of [C]lignocellulose decomposition were greatest during the first 6 days and then began to decline over the remaining 12 days. Total CO(2) evolution was also highest at day 6 and declined steadily over the remaining duration of the incubation. Filtrate NH(4)-N increased from background levels to a final value of 57 mug of N per treatment. Filtrate NO(3) N completely disappeared by day 6, and organic N showed a slight decline between days 12 and 18. The majority of the N that could be recovered appeared in the particulate organic fraction by day 6 (41 mug of N), and the filtrate NH(4) N fraction contained 11 mug of N by day 18. The N enrichment values of the filtrate NH(4) and the inorganic N associated with the particulate fraction had increased to approximately 20 atom% N by 18 days of incubation, whereas the particulate organic fraction reached its highest enrichment by day 6. Measurements of N(2) fixation and denitrification indicated an insignificant gain or loss of N from the experimental system by these processes. The data show that woody debris in stream ecosystems might function as a rapid and efficient sink for exogenous N, resulting in stimulation of wood decomposition and subsequent activation of other N cycling processes.

Mineralization of cellulose in the presence of chitin and assemblages of microflora and fauna in soil.

Nitrogen content is an important factor controlling decomposition of resistant substrates. We examined the decomposition of purified cellulose in the presence of a structurally similar, resistant organic N compound, chitin. Carbon-14-labelled cellulose was added to sterile ari-dried sandy loam soil in flasks, half of which were also amended with purified chitin. Grassland soil organisms-a fungus (Fusarium oxysporum) or a bacterium (Flavobacterium sp.) with or without their respective nematode grazers (Aphelenchus avenae or Pelodera sp.) were added to the substrateamended soils, and decomposition was monitored by carbon dioxide evolution and NH 4+ -N mineralization. More 14CO2 was evolved and at a higher rate from the fungal treatment than from the bacterial treatment. Grazing enhanced 14CO2 and total CO2 evolution and NH 4+ -N mineralization in the bacterial treatments and NH 4+ -N mineralization in the fungal treatments. Nitrogen was mineralized both from native organic sources and from chitin. The addition of chitin did not enhance and, in most cases, decreased cellulose decomposition.

The Effect of High 2,4‐D Concentrations on Degradation and Carbon Dioxide Evolution in Soils

AbstractA laboratory experiment was conducted to determine the degradation of high concentrations of 2,4‐D (2,4‐dichlorophenoxyacetic acid) and CO2 evolution in three soils. Two forms of 2,4‐D, technical grade and formulated, were added to each soil at rates of 50, 500, 5,000 and 20,000 µg/g of soil (ppm). Degradation of the 2,4‐D was measured by 14CO2 evolution resulting from the oxidation of uniformly ringlabeled carbon. At an application rate of 500 ppm, all three soils degraded 2,4‐D. At 5,000 and 20,000 ppm, degradation occurred in the Webster silty clay loam and Terra Ceia organic soil, but not in the Cecil sandy loam during 80 days of incubation. The degradation rate was generally higher for the formulated 2,4‐D than the technical grade material. For the higher 2,4‐D concentrations, 5,000 or 20,000 ppm, when extensive degradation occurred, total CO2 evolution was also greatly stimulated, and the pattern of total CO2 evolution rate exhibited a two‐peak response. Carbon dioxide‐carbon (CO2‐C) from the first peak appeared to be mainly from the formulation materials or from the impurities and CO2‐C from the second peak was mainly from 2,4‐D‐C.

Effects of Temperature and Moisture on Carbon Dioxide Evolution in a Mixed Deciduous Forest Floor

Rates of CO2 evolution from forest litter and soil reflect the metabolic activity of the biota, including live roots and organisms responsible for decomposition. The objective of this study was to quantify the relationship of temperature and moisture to forest floor CO2 evolution in a mixed deciduous forest with the expectation of using this relationship to predict temporal changes in CO2 evolution rates in this and other similar forest ecosystems. Mean daily total CO2 evolution, measured via the inverted box method and infrared gas analysis, exhibited a significantly strong relationship with mean daily litter temperature (R = 0.94). Measured rates (3924 g CO2 m 2 year ) were < 3% higher than those predicted from a regression equation with litter temperature as the independent variable. Litter respiration rates measured with a differential respirometer at field temperatures were equivalent to 838 g of CO2 m 2 year. These values were subtracted from total CO2 efflux measurements for an estimate of 3086 g of CO2 m 2 year 1 evolved from the soil (including roots). This rate was within 1% of the 3095 g m 2 year 1 predicted from mean daily litter temperatures. Estimates based on litter temperatures overestimate CO2 evolution under extreme moisture conditions throughout the year and underestimate in early fall, when litter respiration is high—due in part to increased amounts of readily available energy and nutrients from freshly fallen leaves. Additional Index Words: forest soil respiration, forest litter respiration, oxygen uptake. View complete article To view this complete article, insert Disc 3 then click button8

Microbial Decomposition of Ring‐14C Atrazine, Cyanuric Acid, and 2‐Chloro‐4,6‐diamino‐s‐triazine

AbstractThe relative degradation rates of 2.5 ppm 2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine (atrazine), 2,4,6‐trihydroxy‐s‐triazine (cyanuric acid), and 2‐chloro‐4,6diamino‐2‐triazine were studied in Greenfield sandy loam soil and in pure culture. Only 18% of the activity from added ring‐14C labeled atrazine was recovered as 14CO2 after 550 days of incubation at 60% water‐holding capacity. Ring‐14C 2‐chloro‐4,6‐diamino‐s‐triazine yielded 40% of the added activity as 14CO2 during 192 days. After 16 days, 87% of the labeled cyanuric acid had evolved as 14CO2 and after 32 days, the percentage had increased to 96% indicating that after ring cleavage the cyanuric acid C is not used for cell synthesis by the soil organisms. Evolution of 14CO2 from the three compounds was greatly retarded under saturated soil conditions. Losses were less than 0.6% for ring‐14C atrazine during 375 days, 83% for cyanuric acid in 66 days and 22% for 2‐chloro‐4,6‐diamino‐s‐triazine in 192 days. If cyanuric acid and 2‐chloro‐4,6‐diamino‐s‐triazine are intermediates in atrazine degradation, their detection in soils would be difficult because they are more rapidly oxidized than atrazine.Atrazine did not affect the activity of the soil microbes as measured by total CO2 evolution, numbers of microorganisms, or ability of soil microbes to decompose lima bean straw (Phaseolus limensis).Pure culture studies with two soil fungi, Stachybotrys chartarum and Hendersonula toruloidea, showed that neither was able to cleave the s‐triazine ring of atrazine or 2‐chloro‐4,6‐diamino‐s‐triazine, but both could degrade cyanuric acid to CO2.

Evidence for Photorespiration in Tropical Grasses

AbstractSugarcane leaves respired in full light and the CO2 evolved could be detected in sorghum or miaze photosynthesizing in the same closed system. A combination of radiometric and infra‐red gas analysis techniques allowed the estimation of photorespiration (total CO2 evolution in light) and photosynthesis at increasing light intensities and of dark respiration. Rates of CO2 evolution approaching those of temperate zone plants occurred at lower light intensities but rapidly decreased with higher light. Smaller but significant quantities of 14CO2 were released even at intensities approximating full sunlight in leaves of maize, sorghum and sugarcane. Highly efficient CO2 capture may explain the low rates of photorespiration at high light intensities.

Carbon Dioxide Evolution from the Floor of Three Minnesota Forests

Carbon dioxide evolution rates from forest floors, measured approximately weekly for 54 weeks in oak forest, marginal fen, and cedar swamp, were closely related to soil temperature and secondarily to moisture conditions. As a result, microclimatic and drainage characteristics of the three forests produced seasonal differences in carbon release. However, compensatory factors produced nearly equal cumulative annual totals of CO2 evolution. Total CO2 evolution was over three times higher than expected from an equivalent amount of carbon release from annual litter fall. Respiration by tree roots was suspected as the major contributor to this disparity although methodological problems related to flow rate are still open to question.