Gram Of Carbon Research Articles

Southwest Monsoon of 1979: Chemical and Biological Response of Somali Coastal Waters

In 1979 two areas of upwelling were observed off Somalia, one near 10 degrees N and one near 5 degrees N. The areas of upwelling were characterized by sea surface temperatures between 17 degrees and 22 degrees C, high concentrations of surface nutrients (5 to 20 micromoles of nitrate per liter) and surface chlorophyll a (0.4 to 5.0 milligrams per cubic meter), primary productivity averaging 1.7 grams of carbon per square meter per day, and a phytoplankton assemblage dominated numerically by the diatom Nitzschia delicatissima.

In situ measurements of net primary production in a Colorado mountain stream

Six stations were established on a Colorado mountain stream, and net primary productivity was measured in situ during all seasons. For 24-hour periods the dissolved oxygen and temperature of the water were electronically monitored over an undisturbed 1 x 1 m section of rubble bottom enclosed by a large plastic dome tightly fitted to the substrate. A submerged pump maintained a current within the dome, and the whole apparatus was submerged below the stream level. The bottom community net metabolism varied between heterotrophy and autotrophy with no correlations with altitude, season, light, water chemistry, and temperature. Readings were all very low and ranged from -27.38 to 35.59 grams of carbon fixed per square meter per year. There were no correlations between biomass of the bottom fauna and net community productivity.

Radiocarbon dating in the future; Thirty years after inception

The future of Radiocarbon Dating lies largely in the applications to geoscience and archaeology. We now know of many applications which have never been fully tried, many of them requiring samples which are too small for the present measuring techniques. All present techniques require several grams of carbon per sample, and many applications provide samples of only a few milligrams each. Think of sea cores; quite a few millimeters of precious sea core are required to furnish only a few milligrams of organic material. Radiocarbon dating consists of determining the radiocarbon content of the organic matter of once living materials. The ratio of radiocarbon-14 to ordinary carbon-12 in the old sample can be compared with the ratio in living material, and the radiocarbon age thereby computed. Of course one must take all due precautions about cleaning out contaminations f rom modern substances, which have radiocarbon content greater than that of ancient matter. Failure to do so gives a falsely young age. The whole matter of laundering of samples, namely cleaning the sample of modern carbon contamination (or cleaning it f rom oil seeps, millions of years old, which contain no radiocarbon at all) offers enormous opportuni ty for improvement . The elegant techniques of modern analytical chemistry have hardly been brought to bear in full strength on this problem. We have done quite well in the past, finding that samples from different parts of a given site do check, or samples from a given geophysical event, for example the retreat of the last ice age, do check, although collected f rom widely separated areas, in the case of the last ice age from each of the states of the great lakes region. So apparently contaminat ion can be dealt with as we originally envisaged, if samples of large enough size can be obtained. But by pursuing new and heroic modifications of the laundering and of the measuring techniques, for example by isotope enrichment before measuring, it seems likely that Radiocarbon Dates of the future will extend back to a hundred thousand years, and it may be 205 calibrated further by the use of t ime clocks not yet invented and not yet brought to bear on the problem. I have great hopes for chemical clocks such as amino acid dating. What is possible under conditions in the relatively short span of t ime in which we think in Radiocarbon Dating is to learn something about the history of the climate.

The Volume Adsorption Capacity of 0.98 mol% Argon on Activated Carbon at 20°C

The volume adsorption capacity of activated carbon (Columbia type 4 LXC 12/28) at 20°C for 0.98 mol% argon is 0.109 ± 0.004 cm3 (STP) per gram of carbon. This determination is based on a measurement of the time-dependent transmission of argon in helium through an adsorber bed and on the analysis of that measurement in terms of a dispersion model. The transmission is the ratio of the concentration at the outlet of the adsorber bed to that at the inlet. The analysis yields values for the dispersivity as well as the effective adsorptivity. Both parameters are needed to calculate the steady-state transmission of radioactive argon.

Atmospheric Input of Carbon Dioxide from Burning Wood

The atmospheric input of carbon dioxide from burning wood, in particular from forest fires in boreal and temperate regions resulting from both natural and man-made causes and predominantly from forest fires in tropical regions caused by shifting cultivation, is estimated to be 5.7 x 10(15) grams of carbon per year as gross input and 1.5 x 10(15) grams of carbon per year as net input. This is a significant amount as compared to the fossil fuel carbon dioxide produced from the utilization of oil, gas, coal, and limestone, and bears on the hypothesis of the enhanced sedimentation of marine detritus as a removal mechanism of excess atmospheric carbon dioxide.

Biological Consequences of the 1975 El Niño

The weak El Niño event of 1975 had a clearly defined effect on the biological productivity of the southeastern tropical Pacific. During February and March 1975, warm (27 degrees C) water of low salinity (33.5 parts per thousand) and low nutrient content extended south across the equator east of the Galápagos Islands, replacing the nutrient-rich water normally supplied by equatorial upwelling. Equatorial primary production was less than 0.2 gram of carbon per square meter per day, one-fifth of the normal value. At the maximum development of the 1975 event, the coastal region of Peru continued to have strong nearshore upwelling with primary production values greater than 2.5 grams of carbon per square meter per day, although the zone of high production was confined to a 250-kilometer-wide band, one-half its normal width. The biological effects of the 1975 event were short-lived; in April and May 1975 the equatorial region had begun to reestablish its normal levels of primary production.

Removal of Toxic Chemicals from Water with Activated Carbon

Activated carbon was effective in removing fish toxicants and anesthetics from water solutions. Its capacity to adsorb 3-trifluoromethyl-4-nitrophenol (TFM), antimycin, Noxfish(R) (5% rotenone), Dibrom(R), juglone, MS-222, and benzocaine ranged from 0.1 to 64 mg per gram of carbon. The adsorptive capacity (end point considered as a significant discharge) of activated carbon for removal of TFM was determined at column depths of 15, 30, and 60 cm; temperatures of 7, 12, 17, and 22 C; pHˈs of 6.5, 7.5, 8.5, and 9.5; and flow rates of 50, 78, 100, 200, and 940 ml/min. Adsorptive capacity increased when the contact time was increased by reducing the flow rate or increasing the column depth. The adsorptive capacity was not significantly influenced by temperature but was substantially higher at pH 6.5 than at the other pHˈs tested. A practical and efficient filter for purifying chemically treated water was developed.

Caloric content of phytoplankton

There are important theoretical and empirical reasons for expressing calorific values in terms of grams of carbon rather than grams dry weight. For phytoplankton, calorific value may be predicted with fairly high accuracy from carbon content, enabling much smaller samples to be used and resulting in a considerable saving in time. This removes the biggest stumbling block to the routine measurement of the energy efficiency of primary production.

Atmospheric carbon dioxide: its role in maintaining phytoplankton standing crops.

The rate of invasion of carbon dioxide into an artificially eutrophic Canadian Shield lake with insufficient internal sources of carbon was determined by two methods: measuring the carbon : nitrogen : phosphorus ratios of seston after weekly additions of nitrogen and phosphorus, and measuring the loss of radon-222 tracer from the epilimnion. Both methods gave an invasion rate of about 0.2 gram of carbon per square meter per day. The results demonstrate that invasion of atmospheric carbon dioxide may be sufficient to permit eutrophication of any body of water receiving an adequate supply of phosphorus and nitrogen.

OXYGEN BALANCE IN SOME REEF CORALS

Oxygen exchange is reported for 14 species of Florida reef corals in the dark and at different light intensities. Oxygen tension was monitored with a recording polarographic electrode. Results are given as grams of carbon fixed per square meter of coral surface per day, and compensation light intensities were given for each species. Maximum ratios of photosynthesis to respiration varied from 1.9 to 5.8. Boring, filamentous green algae living in the skeleton of Dichocoenia stokesii were not observed to change their rate of oxygen consumption from dark conditions up to 5000 footcandles of light. It is concluded that reef corals are among the most productive organisms known and that, in Florida corals, the boring green algae contribute very little indeed to this productivity. Some data are given on the light impinging on Florida reefs and the light penetrating coral skeleton. Reasons for believing boring green algae are of minor importance are given in the discussion.

Atmospheric bomb radiocarbon as a tracer in human beings.

The level of radiocarbon in atmospheric carbon dioxide has risen to almost double the natural or reference level of 1890 (about 14 dpm per gram of carbon) as a result of the testing of fission and fusion bombs. It has reached a concentration that can be measured in living tissues by low-level carbon-14 counting equipment.

A sampler for radiocarbon in surface air

Compact, automatic equipment for the collection of carbon dioxide from surface air at ambient temperature is described. An oil-free, diaphragm-type compressor pumps air through a silica gel bed, which removes water vapor, and then through a bed of Linde 5A molecular sieve, which adsorbs carbon dioxide quantitatively. The sample is collected over periods of 24 to 28 hours to minimize the influence of transient conditions. In this period, approximately 10 liters of carbon dioxide, equivalent to 5 grams of carbon, are collected. The carbon dioxide is desorbed from the molecular sieve by heating to 500°C and is transferred in vacuo to a purification train. The C14 content of biweekly samples is measured in 7.5-liter gas proportional counters. The specific activity of the carbon increased over the period January 1964 to December 1964, showing that C14 from a stratospheric reservoir was continuously entering the troposphere. However, the values from the first half of 1965 were lower and varied slightly.

The kinetics of the system carbon-hydrogen-methane

In a study of the kinetics of the system carbon-hydrogen-methane, the methane formation rate was determined at pressures up to 40 atm and in the temperature range 650 to 870°C, and the methane decomposition rate a t pressures up to 20 atm and in the temperature range 850 to 725°C. The rate of methane formation, expressed as gram moles per minute per gram of carbon originally in the bed, can be expressed by the equation Formula where k1, k2, k3, k4, and k5 are constants and pH2 and PCh4 are the partial pressures, in atmospheres, of the hydrogen and methane respectively. A mechanism has been suggested which involves the formation of >CH2 groups on the carbon surface.

Primary Production of Vascular Aquatic Plants

In this paper, data are presented on the productivity of four hay crops, five prairie plots, one floodplain community, one cultivated aquatic crop, two emergent plant populations, and two floating mat communities. The productivity (production rate) of the communities investigated varied with the amount of light, water, and nutrients available. The average productivity, in grams of carbon per square meter per day, based on the terminal crop, was moderate (1.5) in hay crops, tall grass prairie and rice, relatively high (3.6) in giant ragweed and presumably still higher in certain aquatic plants. The terminal standing crop was found to be less than the sum of periodic measurements of the developing crop. It was noted also that the magnitude of productivity values depended upon the time of harvest. The productivity of vascular aquatic plants was usually highest in spring and autumn and lowest during the summer. Low summer productivity was due primarily to the relatively low rate of photosynthesis, compared with that of respiration, during hot summer weather. On the basis of present data it appears that productivity in the terrestrial habitat was greatest along shorelines of water bodies and did not increase continuously in the hydrarch succession toward the regional climax.

Studies on the Growth and Development and Morphine Content of Opium Poppy

1. An attempt was made to correlate the growth and development and morphine content of Yuma poppy, U.S.D.A. no. 17 (Papaver somniferum L.) grown under usual greenhouse conditions with that of plants grown under controlled temperatures and photoperiods. 2. The concentration of morphine (μg/gm dry weight) in organs of plants first grown on an 8-hour day, then on 18-hour photoperiods at 49-59 days after seed germination, and then transferred to natural daylengths in the greenhouse was greatest in the capsules, while none was detected in the seed. In plants harvested 32, 61, 98, 114, and 126 days after seed germination, the capsules collected at 98 days contained the highest concentration of morphine, while capsules collected at the last harvest contained the greatest amount of morphine (concentration x dry weight). On a whole-plant basis the greatest concentration of morphine was found in plants harvested 98 days after germination, whereas the greatest amount of morphine was found in plants collected after 98 and 114 days. 3. The mean number of nodes produced by plants grown under certain artificial conditions is related to the average dry weight of the capsule. The number of nodes and the dry weight of capsules of plants placed on inductive 18-hour photoperiods 14, 30, 45, or 64 days after seed germination were directly proportional. 4. A relationship was found between the mean number of nodes produced and the following daily photoperiods: 10, 11, 12, 14, 15, 16, 17, 18, or 24 hours. The number of nodes on plants exposed to all photoperiods greater than 15 hours was approximately the same, while that on plants exposed to photoperiods of less than 15 hours was greatest for the 10- and 11-hour photoperiods. 5. The concentration of morphine in capsules and roots of plants grown at 50⚬ or 70⚬ F. in controlled-temperature rooms was greater at the lower temperature, while that in the straw (stems plus leaves) was greater at the higher temperature. The total dry weight of capsules produced by plants grown at 70⚬ was 37% greater than that for plants grown at 50⚬; however, the dry weight of straw and roots of plants grown at the lower temperature was at least 34% greater than that of plants grown at the higher temperature. 6. In thermoperiodicity studies on plants induced to flower at 65⚬ F. with fourteen 18-hour photoperiods, the production of dry weight of shoots (all aerial organs) per day was greater when the day temperature was 65⚬ than at 82⚬, and when the night temperature following these two day temperatures was 48⚬ than when it was 82⚬ or 65⚬. At each of the two day temperatures employed the dry weight of shoots produced was greatest when the night temperature was lower than the preceding day temperature. At high night temperatures the time to flowering was shortened and the rate of flowering and the concentration of morphine increased as compared with effects of the low night temperatures, while height, dry weight, length of peduncle, and area of leaves were greater at the low night temperatures. The total morphine content was apparently increased by low night temperatures if it is assumed that photosynthesis was more limiting during the 82⚬ day than at the 65⚬ day. 7. Inhibition of floral induction at 84⚬ ± 6⚬ F. during the supplemental photoperiod and subsequent dark period occurred in plants exposed to 14, 15, 16, 17, or 18-hour photoperiods for 45 days. Of the total population, 7% flowered, while all remaining plants were vegetative. These predominantly rosette plants, including an 8-hour control, were then grown for 96 days on an 82⚬ day, and on night temperatures maintained at 82⚬, 65⚬, or 48⚬. On a dry-weight basis the intermediate night temperature was most favorable. A possible shift in optimum night temperatures for the production of leaves and leaf size was indicated. 8. The following culture conditions are indicated for the optimal production of morphine in biosynthesis studies: After germination of seeds at 70⚬-80⚬ F., seedlings are grown on an 8-hour day at 60⚬-70⚬, utilizing natural sunlight. Induction of flowering occurs as a result of exposure to fourteen 18-hour days at 60⚬ when thirty to thirty-five leaves have been formed. Floral induction and total leaf number are determined by microdissection. Plants are then transferred to the biosynthesis chamber, which is maintained on an 18-hour day at 60⚬-65⚬. Sunlight is supplemented with artificial illumination from twelve 40-watt G.E. DeLuxe Warm White lamps mounted inside the chamber. Radioactive morphine with a specific activity of 0.5 mc. per gram of carbon has been obtained from Yuma poppies treated in this manner.

Solubility and Diffusion Coefficient of Carbon in Nickel: Reaction Rates of Nickel-Carbon Alloys with Barium Oxide

Experimental values for the solubility of carbon in nickel in the range 700°C to 1300°C yield the equation lnS=2.480−4,880/T, where S is the solubility in grams of carbon per 100 grams of nickel. Values obtained for the diffusion coefficient in the same range fit the equation lnD=0.909−20,200/T, where D is in cm2 per second. These results are of some interest in the problem of the activation of thermionic oxide coated cathodes, and the experimental method used to measure the diffusion coefficients is related to phenomena occurring in vacuum tubes. To extend the usefulness of the results in this direction, rates of reaction between diffused carbon and barium oxide coatings on nickel have been measured. It was found that the rates are diffusion limited over a wide range of conditions of interest.

Molasses andmohua flowers as sources of energy for azotobacter

Both molasses andmohua flowers serve as source of energy for azotobacter, but the amount of nitrogen fixed per gram of material or per gram of carbon supplied is much less than in the case of mannite. In this respect,mohua flowers which contain larger amount of nitrogen than molasses are a greater offender. Even at very low concentrations, molasses is less efficient than mannite.

The Specific Dynamic Effects of Amino Acids and Their Bearing on the Causes of Specific Dynamic Effects of Proteins

The specific dynamic effects of glutamic acid, glycine, alanine, tyrosine, aspartic acid and asparagine were determined by feeding these amino acids to rats in considerable quantities (some equicaloric) as supplements to a basal maintenance ration. The increases in heat production due to the supplements were measured with respect to the heat production of maintenance as a base value. All amino acids showed positive dynamic effects. The results were expressed in ten different ways, and a study was made of the relationships between the heat increments and the various metabolic factors. The heat increments expressed in relation to ingested or urinary nitrogen, as well as the values expressed per millimol of amino acid metabolized, were found to be highly variable, and showed no direct correlation between the specific dynamic effects of amino acids and nitrogen metabolism. The results expressed as Calories per gram of carbon of the amino acids metabolized were much more uniform than those expressed per gram of extra urinary nitrogen, thus indicating that the metabolism of carbon is probably a more important factor in the production of the specific dynamic effects than is the metabolism of nitrogen. The closest correlation was found between the dynamic effects and the metabolizable energy of the amino acids. The results are consistent with the theory that dynamic effects of amino acids, and therefore of proteins, are byproducts of intermediary chemical reactions (oxidative and synthetic) and energy changes, and they do not lend support to the idea that certain amino acids or certain of their cleavage products act in the body as special metabolic stimulants in the pharmacodynamic sense.

The Concentration of C13

The chemical exchange method has been applied to the separation of the isotopes of carbon. Various exchange reactions have been tested, using counter-current flow in packed fractionation columns, and of these, the exchange between hydrogen cyanide gas and a solution of sodium cyanide in water has been found to be most efficient. In this exchange, the isotope of carbon of atomic weight 13 (ordinarily present to the extent of 1.06 percent) is concentrated in the gas phase. Suitable conditions for the exchange have been determined, and a satisfactory apparatus has been devised. Using two fractionation units in a cascade arrangement, sodium cyanide, containing carbon of 25 atom percent C13, has been produced at a rate of 2.5 grams per day. This corresponds to a transport of 0.15 grams of C13 per day. In all, more than 20 grams of carbon, containing 25 percent of C13, and additional quantities of less concentrated material, have been obtained in this way.

Determination of Total Moisture in Carbon Blacks

Abstract IN THE course of an extended research on various grades of carbon black, determinations of total moisture were made by an adaptation of an old method. The method used was similar to one described by Allen and Jacobs (1) for measuring water in tar. The chief difference in the present method is that small amounts of moisture in carbon blacks must be weighed, whereas the larger amounts in tar could be measured. The difficulties in weighing the evolved moisture are described in the ensuing method of determination. Five grams of carbon black were placed in a 500-cc. round-bottom flask with 25 to 35 cc. of dry xylene and 200 cc. of dry mineral oil. A short air condenser led to the bottom of a 25-cc. distilling flask, which in turn was connected to two or more calcium chloride tubes. The flask containing the sample was heated to 150-175° C. in an oil bath, a stream of dry nitrogen being passed through the apparatus. The water and xylene were distilled into the small distilling flask and thence, by warming in a water bath, into the calcium chloride tubes, the current of nitrogen being continued. It required but a few minutes to remove the water from the xylene, indicated by the disappearance of cloudiness, and the calcium chloride tubes were then connected directly to the nitrogen line and the gas was passed through until the tubes reached constant weight. ylene is not adsorbed by calcium chloride and nitrogen does not remove water from it at room temperature during the time required for the experiment. The increase in weight of the calcium chloride tubes is the amount of water in the sample of carbon black. The amount of water thus determined is considerably higher than the 105° C. oven loss in 5 hours, and indicates that most of the moisture is of the “bound” or “capillary” type.