Methane concentrations have been measured in the surface waters and at depth for several different marine environments. Measurements have also been made in rain water collected in Washington, D.C., over the Pacific Ocean, and in Hawaii. In tropical open ocean areas, surface water concentrations average 4.5 × 10−5 ml/l and decrease to values approaching 0.6 × 10−5 ml/l at a depth of 5000 meters. In natural anoxic conditions (i.e., Cariaco Trench, Black Sea, Lake Nitinat) concentrations can increase as much as four orders of magnitude. In the case of Lake Nitinat, 1.6 ml/l is found at a depth of 200 meters. Nearshore and bay concentrations can be 2–3 orders of magnitude higher than open ocean surface values. Open ocean surface waters are slightly supersaturated with methane, whereas estuary systems are highly supersaturated. Open ocean surface values remain fairly constant, whereas bay and river systems vary considerably, depending on the time of year, addition of pollutants, and tidal mixing. Rain water analyses yielded an average concentration of 5.0 × 10−5 ml/l for the Hawaiian and Pacific samples, and an average concentration of 8.8 × 10−5 ml/l was found for the Washington, D.C., area. Atmospheric methane concentrations over the open ocean remain fairly constant at 1.4 ppm. Atmospheric values in Washington, D.C., at NRL averaged 1.7 ppm.
Carbon monoxide, ethylene, and propylene were produced in illuminated, cell-free distilled water or natural seawater systems to which dissolved organic matter produced by phytoplankton had been added. Methane and the higher saturated gaseous hydrocarbons were not produced. In the dark, little or no carbon monoxide and no hydrocarbons were produced in the distilled water systems; only carbon monoxide was produced in natural seawater, but less was produced than in the light.
bon tetrachloride layer is shonn in Figure 6. Peaks 5, 9, and 10 decreased. On closer observation, it can be seen that peak 10 has shown a smaller decrease than either peak 5 or peak 9. The peak heights of components 9 and 10 are reversed after extraction. The carbon tetrachloride layer mas extracted once more nith propylene glycol. Figure 7 shoii s the chromatogram of the second carbon tetrachloride eLtract. Peaks 5 and 9 have decreased greatly and are almost absent. Removing most of component 5 has shown the presence of a minor component, which was not resolved in the original chromatogram. Peak 10 shows only a very small decrease after the second extraction. This fact indicates that peak 10 is actually composed of more than one component, one of mhich must be an alcohol. The major portion of this compound was removed in the first extraction. The other component of peak 10 has been identified as geranyl formate by its retention time.To establish the identity of the three alcohols, the infrared spectra of both the layers of the initial extraction mere run and are shown in Figure 8 To find out nliich bands in the spectrum are due to alcohols, one chooses those bands that are stronger in the propylene glycol layer. These bands appear a t 2. 90, 9.00, 9.45, and 10.05 microns. The band a t 9.00 microns is due to linalool. The band a t 9.45 microns is due to citronellol, and a t 10.05 microns, the band is assigned to geraniol. The bands a t 9. 75, 5.82, 7-95, 8.15, 8.55, and 11.25 microns appear much stronger in the carbon tetrachloride layer. These bands must be due to esters, ketones, or terpenes.The band a t 5.75 microns has been assigned to the esters, and the one a t 5.85 microns to menthones. The bands a t 7.95 and 8.15 microns are assigned to citronellyl acetate and geranyl acetate, respectively. The band a t 8.55 microns is due to citronellyl and geranyl formates. The band a t 11.25 microns is due to terpenes. The infrared spectra of the extraction layers enable one to determine which bands in the original spectrum are due to alcohols and which are not. If there is doubt concerning any band because of almost equal intensity in both layers, this can be resolved by looking a t the spectra of further eutractions. The infrared b A gas chromatographic method has been developed for the determination of small amounts of dissolved gases in aqueous solutions. The equipment consists of an all-glass sample chamber in which the dissolved gases are stripped from solution b y an inert carrier gas, a four-way by-pass valve, a commercially available gas partitioner, and a 1-mv. recorder. Calibration for routine work is accomplished b y carrying out the determination on a sample of water saturated with pure gas at a known temperature and pressure. At present, the method is capable of determining dissolved gas concentrations as low as 0.3 p.p.m. in 1 -to 2-ml. samples of solution.
The surface waters of the western Atlantic are supersaturated with respect to the partial pressure of carbon monoxide in the atmosphere. Under these conditions, the net transport of carbon monoxide across the air-sea interface must be from the sea into the atmosphere. Thus, the ocean appears to act as a source of carbon monoxide. The ocean may be the largest known natural source of this gas, contributing possibly as much as 5 percent of the amount generated by burning of fuels by man.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.