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Weiss, RF.  1981.  The temporal and spatial distribution of tropospheric nitrous oxide. Journal of Geophysical Research-Oceans and Atmospheres. 86:7185-7195.   10.1029/JC086iC08p07185   AbstractWebsite

The concentration of nitrous oxide has been measured in air samples collected between 1976 and 1980 at several monitoring stations and aboard Oceanographic vessels in the major world oceans. These measurements demonstrate that the tropospheric nitrous oxide concentration is increasing at ∼0.2% per year, thus confirming earlier observations of the increase based on stored samples. The measurements also show that the concentration of nitrous oxide in the northern hemisphere is higher than in the southern hemisphere, the average difference during the sampling interval having been about 0.8 parts per billion (ppb), compared to a January 1, 1978 northern hemisphere dry air mole fraction of 300.2 ppb. The data are well represented by a simple box model which relates the tropospheric rate of increase to an exponentially increasing source function. The observed increase may be explained by combustion of fossil fuels and agricultural activity, with a total source strength of ∼11 × 1010 mol/yr as of January 1, 1978. A substantial fraction of this production is explained by combustion, and agricultural production is therefore considerably less than has been previously estimated. The concentration of nitrous oxide in the preindustrial unperturbed troposphere is estimated to have been between 281 and 291 ppb, depending upon the rate of increase of the mean anthropogenic source function, and the preindustrial latitudinal distribution is estimated to have been nearly uniform. According to the model projections, the concentration of tropospheric nitrous oxide in the year 2000 will be 5 to 7% above present values. The observed rate of tropospheric increase directly affects the production of stratospheric nitric oxide, and plays a significant role in the earth's radiation balance, conservatively estimated as 10–15% of the effect due to increasing carbon dioxide.

Lupton, JE, Klinkhammer GP, Normark WR, Haymon R, Macdonald KC, Weiss RF, Craig H.  1980.  Helium-3 and manganese at the 21°N East Pacific Rise hydrothermal site. Earth and Planetary Science Letters. 50:115-127.   10.1016/0012-821x(80)90123-5   AbstractWebsite

Water samples collected at the 21°N hydrothermal site on the East Pacific Rise crest, including Deep-Tow and hydrocast samples collected in 1977 and three hot vent water samples collected recently with the submersible “Alvin”, contain significant additions of3He,4He, and Mn. Although the vent water collections were at least 50-fold diluted with ambient seawater, they are up to 53 times enriched in3He and 7.4 times enriched in4He relative to saturated seawater, with concentrations of total dissolvable manganese (TDM) up to 310 μg/kg.3He and4He covary in the vent samples, with3He/4He about 8 times the atmospheric ratio, reflecting a mantle helium source. In contrast to the helium isotopes the Mn/3He ratio in the vent samples is variable, ranging from 4.3 × 104 up to 1.0 × 105 g/cm3. Profiles of3He/4He and TDM in the water column at 21°N show a sharp maximum ofδ(3He) = 47%and TDM= 0.69 μg/kg, much higher than the average values of 34% and 0.2 μg/kg for the deep water in this region. This spike in3He and Mn occurs at 2400 m depth, 200 m above the level of the 21°N vents, and 100 m higher than any local bathymetry, evidence for upward transport of the hydrothermal discharge via rising plumes of hot vent water. Two of the 21°N Deep-Tow samples associated with small (⩽0.010°C) temperature anomalies hadδ(3He) = 38%and TDM= 0.28 and 0.58 μg/kg, also slightly elevated relative to background. The Deep-Tow and hydrocast samples have lower Mn/3He ratios than average vent samples due to Mn removal by scavenging. Comparison of vent samples and water column measurements at 21°N indicate that the pure vent water could be detected using3He and Mn even when diluted ∼105 times with seawater, confirming that these two tracers are extremely sensitive indicators of submarine hydrothermal activity.

Weiss, RF, Price BA.  1980.  Nitrous oxide solubility in water and seawater. Marine Chemistry. 8:347-359.   10.1016/0304-4203(80)90024-9   AbstractWebsite

The solubility of nitrous oxide in pure water and seawater has been measured microgasometrically over the range 0–40°C. The data have been corrected for nonideality and are fitted to equations in temperature and salinity of the form used previously to fit the solubilities of other gases. The fitted values have a precision of 0.1% and an estimated accuracy of 0.3%. The nonideal behavior of nitrous oxide—air mixtures is discussed, and the solubility of atmospheric nitrous oxide is presented in parametric form. A similar parametric representation for the solubility of atmospheric carbon dioxide is given in the Appendix.

Weiss, RF, Ostlund HG, Craig H.  1979.  Geochemical studies of the Weddell Sea. Deep-Sea Research Part a-Oceanographic Research Papers. 26:1093-1120.   10.1016/0198-0149(79)90059-1   AbstractWebsite

The origin of Antarctic Bottom Water is discussed in terms of the distributions of a number of geochemical tracers in the major water masses of the Weddell Sea. Oxygen, phosphate, nitrate and total inorgabic carbon are shown to be negligibly altered by consumption or production during sub-surface circulation and mixing. All the conservative properties of Weddell Sea Bottom Water and Antarctic Bottom Water are explained as simple mixtures of Winter Water, Warm Deep Water, and Western Shelf Water. Silica is markedly non-conservative, showing enrichments up to ≈35 μM kg−1 which are due mainly to interactions with the bottom. The deuterium and oxygen-18 stable isotope data show that the high salinity of Western Shelf Water is principally the result of freezing rather than evaporation. The isotopic composition of Western Shelf Water also requires a significant admixture of melt-water from the base of the Filchner Ice Shelf, and mass-balance calculations linking the rate of shelf ice melting to the formation of bottom water give a production rate of about 5 × 106 m3 s−1 for Weddell Sea Bottom Water with potentiatial −0.9°C, or about 8 × 106 m3 s−1 in terms of classical Antarctic Bottom Water with a potential temperature of −0.4°C. Concentrations of the radioisotopes carbon-14 and tritium are exceptionally low in the Weddell Sea despite the fact that the CO2 atmospheric exchange rate is comparable to the global average. The low values are seen to be the result of a short surface residence time, a large sub-surface mixing component, and exchange inhibition by sea ice especially during the winter. Unlike the average world ocean, where molecular exchange is about three times more important than precipitation in transporting atmospheric tritium to surface waters, about four times more tritium is added to the Weddell Sea by precipitation than by molecular exchange. The flux of new Weddell Sea Bottom Water based on the tritium data is estimated very roughly at about 3 × 106 m3 s−1, or about 4.5 × 106 m3 s−1 expressed in terms of classical Antarctic Bottom Water.

Edmond, JM, Jacobs SS, Gordon AL, Mantyla AW, Weiss RF.  1979.  Water column anomalies in dissolved silica over opaline pelagic sediments and the origin of the deep silica maximum. Journal of Geophysical Research-Oceans and Atmospheres. 84:7809-7826.   10.1029/JC084iC12p07809   AbstractWebsite

Recent estimates based on pore water studies and mass balance considerations put the average flux of dissolved silica from the sediments into the deep water at about 3 μmol cm−2 yr−1. This flux, if mixed uniformly in a bottom layer 100 m thick, results in an anomaly increment of 0.3 μmol kg−1 yr−1. In basins of restricted circulation containing opaline sediments the residence time of the bottom waters should be long enough that the resulting anomaly be easily resolvable using existing data. Examination of the many hundreds of detailed, precise silica profiles presently available in unpublished reports shows that this is indeed the case. The largest effects (∼50 μmol/kg) are seen in the Weddell-Enderby Basin. Intermediate anomalies (∼20 μmol/kg) are prevalent in the northern Indian Ocean. Lesser features (∼10 μmol/kg) are clearly discernable in the other antarctic basins and in the north Pacific. No anomalies are observed over the equatorial Pacific and Indian bands of opaline deposits, even in the basins east of the East Pacific Rise or in the Central Basin of the Indian Ocean. The flux of dissolved silica from the sea floor is generally unaccompanied by any resolvable oxygen consumption, indicating that relatively minor amounts of organic material reach the sediments in these regions. However, in the north Indian Ocean there are pronounced effects on all the nutrients, oxygen, and alkalinity, with regeneration approximating the Redfield prediction. In the northern Indian Ocean and the extreme northeast Pacific (northeast of 45°N, 160°W) the silica profiles increase to the bottom. This is a strong indication that the deep silica maximum observed over much of these oceans may have a large advective component, the feature itself being induced by the northward flow of the underlying low-silica bottom waters. In the Indian Ocean the data coverage is sufficient to demonstrate unequivocally the dominance of this effect.

Weiss, RF, Kyser TK.  1978.  Solubility of krypton in water and seawater. Journal of Chemical and Engineering Data. 23:69-72.   10.1021/je60076a014   AbstractWebsite
Weiss, RF, Kirsten OH, Ackermann R, Ramo S.  1977.  Free vehicle instrumentation for the in-situ measurement of processes controlling the formation of deep-sea ferromanganese nodules. OCEANS '77 Conference Record. , New York, N.Y., United States (USA): Inst. Electric. and Electron. Eng., New York, N.Y.   10.1109/OCEANS.1977.1154352   Abstract

This paper describes the free vehicle instrumentation under development for the Manganese Nodule Program (MANOP) of the International Decade for Ocean Exploration (IDOE). Principal emphasis is being placed on the MANOP Bottom Lander, a device designed to carry out in situ chemical flux experiments at the seawater-sediment interface at depths up to 6 km. This device will collect time-series water samples from three separate bottom chamber experiments, each of which can be spiked with various chemical and radioisotopic tracers. The device will also make oxygen and pH measurements in each chamber and will take box core samples under each chamber before returning to the surface. All operations will be microprocessor-controlled with data storage capability and with an acoustic data-link to the surface. Deployments will be for periods of up to 1 year.

Weiss, RF.  1977.  Hydrothermal manganese in the deep sea: Scavenging residence time and Mn/3He relationships. Earth and Planetary Science Letters. 37:257-262.   10.1016/0012-821x(77)90171-6   AbstractWebsite

Measurements of hydrothermal Mn in the water column overlying the Galapagos Rift have been fitted to a one-dimensional first-order scavenging model. Assuming a vertical advection velocity of 4 m/yr, the model gives a scavenging residence time for Mn of 51 years. The horizontal propagation distance for hydrothermal Mn in the water column is thus estimated to be on the order of 1000 km. The Mg/3He injection ratios for the Galapagos Rift hydrothermal plume samples and the Red Sea brines are in close agreement. The Mn flux determined from the scavenging model and the estimates of Mn flux based on the Mg/3He injection ratio are compared to the Mn accumulation rates observed in deep-sea sediments.

Klinkhammer, G, Bender M, Weiss RF.  1977.  Hydrothermal manganese in the Galapagos Rift. Nature. 269:319-320.   10.1038/269319a0   AbstractWebsite

HYDROTHERMAL emanations originating at mid-ocean ridges have been thought1–5 to provide a substantial source of manganese to the ocean but the evidence supporting this hypothesis has been indirect. Anomalous manganese concentrations have been measured in naturally occurring systems where seawater is in direct contact with lava flows6–8. Laboratory studies have shown that seawater tends to leach manganese from basalts at elevated temperatures and pressures9–11. Anomalously high manganese accumulation rates have also been determined for sediments adjacent to active ridge systems, most notably the East Pacific Rise12–14. No measurements of manganese concentrations in seawater near mid-ocean ridges, or in hydrothermal fluids emanating from these ridges, have yet been made, however. We report here the results of the first such direct measurements, which show that manganese is being injected into the deep sea by hydrothermal circulation of seawater through newly-formed oceanic crust.

Weiss, RF, Lonsdale P, Lupton JE, Bainbridge AE, Craig H.  1977.  Hydrothermal plumes in the Galapagos Rift. Nature. 267:600-603.   10.1038/267600a0   AbstractWebsite

ALTHOUGH there is indirect evidence that a major fraction of the heat loss from newly-created lithosphere occurs by convection of seawater through the porous crust1–3, it has proved difficult to locate vents of deep-sea hydrothermal systems by direct measurement of the discharge fluid. Local increases in bottom water temperature up to 0.1 °C have been measured by towing arrays of thermistors a few metres above the axes of active oceanic spreading centres4,5, but these data are ambiguous because small temperature anomalies may have a hydrographic explanation. We report here the first conclusive measurements of modified seawater discharging as buoyant hydrothermal plumes from fissures in young oceanic crust. We obtained samples of hydrothermal plumes in the Galapagos Rift3, albeit after considerable dilution with surrounding bottom-water, and report the first results of the collection and analysis of these samples.

Imboden, DM, Weiss RF, Craig H, Michel RL, Goldman CR.  1977.  Lake Tahoe geochemical study .1. Lake chemistry and tritium mixing study. Limnology and Oceanography. 22:1039-1051. AbstractWebsite
Lupton, JE, Weiss RF, Craig H.  1977.  Mantle helium in hydrothermal plumes in the Galapagos Rift. Nature. 267:603-604.   10.1038/267603a0   AbstractWebsite

THE 3He/4He ratio in deep Pacific water is 20–30% higher than in atmospheric helium because of injection of primordial helium from the mantle1,2. The largest 3He enrichments in the Pacific have been found in water on the crest of the East Pacific Rise where the isotopic ratios indicate2 that the excess helium component has a 3He/4He ratio about ten times the atmospheric ratio, in agreement with the ratios measured in trapped helium in the glassy rims of oceanic tholeiites3,4. Recent measurements in this laboratory5 have shown that the hot brines in the axial rift of the Red Sea are very highly enriched in mantle helium. 3He and 4He are respectively 3300 and 380 times supersaturated relative to atmospheric solubility equilibrium in seawater, with a 3He/4He ratio of 1.2×10−5, or 8.6 times the ratio in atmospheric helium. Comparison of the enrichments of various elements in the Red Sea brines and in brines associated with salt domes6 shows that helium is the only component in the Red Sea brines which unequivocally requires derivation from hydrothermal circulation of seawater in basalts. The helium isotopes are thus an extremely powerful and sensitive tracer for the detection and mapping of hydrothermal systems in oceanic spreading centres.

Lupton, JE, Weiss RF, Craig H.  1977.  Mantle helium in the Red Sea brines. Nature. 266:244-246.   10.1038/266244a0   AbstractWebsite

HELIUM isotope studies on terrestrial samples have revealed the existence of two helium components which are clearly distinct from atmospheric helium. The first of these, which we term ‘crustal helium’, was identified in 1946 in natural gas wells1. This crustal component is produced by radioactive decay of U and Th to 4He, with 3He production by (n, α) reactions on Li; the resulting helium is characterised by 3He/4He ≃ 10−7, one-tenth of the atmospheric ratio2. The second component, ‘mantle helium’, was discovered as ‘excess 3He’ in deep ocean water, attributed to a flux of primordial helium from the mantle3. Studies of the 3He/4He ratio in deep water on the East Pacific Rise4 and in helium trapped in submarine basalt glasses5,6 have shown that this mantle component is characterised by 3He/4He ≃ 10−5, about 10 times the atmospheric ratio and 100 times the ratio in crustal helium. Basalt glasses from the Western Pacific Lau Basin, the East Pacific Rise, and the Mid-Atlantic Ridge contain trapped helium with similar 3He/4He ratios, indicating that mantle helium in at least three areas in which new lithosphere is being formed has a unique and uniform isotopic signature.

Krishnaswami, S, Lal D, Somayajulu BLK, Weiss RF, Craig H.  1976.  Large-volume in situ filtration of deep Pacific waters: mineralogical and radioisotope studies. Earth and Planetary Science Letters. 32:420-429.   10.1016/0012-821x(76)90082-0   AbstractWebsite

The concentrations of CaCO3 and radioisotopes,234Th,230Th,239Pu,226Ra and210Pb have been measured in particles of >1.2 μm collected from ∼4000 liters of Pacific waters (33°N−33°S; 124°W−170°E) at depths 700–5500 m. The mean “ash” concentrations are found to be 5 μg/kg seawater, about 3–4 times lower than that in the surface waters. The particulate concentrations (dpm/kg seawater) of239Pu shows a peak at 700–1000 m, whereas the particulate concentration of230Th and210Pb which are produced in-situ in seawater increases with depth. These results provide an insight into certain aspects of particle dynamics relevant to modification of trace element composition of seawater due to particle transport and sedimentation flux. The salient features of the results are:(1) The mean settling velocity of particles are in the range of (0.3−2) × 10−3 cm/sec corresponding to a sedimentation rate of 0.1−0.6 cm/103 yr.(2) The rate constant for the adsorption of Th on particles is deduced to be 8 × 10−8 sec−1 assuming a first-order scavenging model.

Weiss, RF, Craig H.  1976.  Production of atmospheric nitrous oxide by combustion. Geophysical Research Letters. 3:751-753.   10.1029/GL003i012p00751   AbstractWebsite

Measurements of N2O in the effluent gases from the burning of coal and fuel oil show that these are significant anthropogenic sources of atmospheric N2O. We estimate that the present global production of N2O from these sources is 1.6 Mtons N2O(N) per year and is increasing at a rate of ∼ 3.5% per year. Catalytic converters for the reduction of NO emissions also represent a major potential source of atmospheric N2O.

Chan, LH, Edmond JM, Stallard RF, Broecker WS, Chung YC, Weiss RF, Ku TL.  1976.  Radium and barium at Geosecs stations in Atlantic and Pacific. Earth and Planetary Science Letters. 32:258-267.   10.1016/0012-821x(76)90066-2   AbstractWebsite

Ra and Ba show a general linear correlation in the oceanic water column within the uncertainties of the data: the slope of the line is about 4.6 nanomoles (nmoles) Ra/mole Ba, the intercept being at about 4 nmoles Ba/kg. This demonstrates the usefulness of Ba as a “chemical analogue” of Ra. Box-model calculations indicate that the average deep-water excess of Ra over Ba should be about 10% relative to the surface. This is consistent with the observations outside the deep northeast Pacific. However, the uncertainties in the data are such that the regional variation in the primary input cannot be resolved. In the deep waters of the North Pacific there is in fact a large excess of Ra relative to Ba. The one detailed profile presently available (204) can be explained consistently by a simple vertical advection-diffusion model.

Weiss, RF.  1974.  Carbon dioxide in water and seawater: the solubility of a non-ideal gas. Marine Chemistry. 2:203-215.   10.1016/0304-4203(74)90015-2   Abstract

New measurements of the solubility of carbon dioxide in water and seawater confirm the accuracy of the measurements of Murray and Riley, as opposed to those of Li and Tsui. Corrections for non-ideal behavior in the gas phase and for dissociation in distilled water are required to calculate solubility coefficients from these sets of data. Equations for the solubilities of real gases are presented and discussed. Solubility coefficients for carbon dioxide in water and seawater are calculated for the data of Murray and Riley, and are fitted to equations in temperature and salinity of the form used previously to fit the solubilities of other gases.

Weiss, RF, Craig H.  1973.  Precise shipboard determination of dissolved nitrogen, oxygen, argon, and total inorganic carbon by gas chromatography. Deep-Sea Research. 20:291-303.   10.1016/0011-7471(73)90054-5   AbstractWebsite

A seagoing gas chromatographic system for the rapid and precise determination of dissolved gases in sea water is described. Separate instruments are employed for total inorganic carbon, and for nitrogen, oxygen, and argon analyses. Factors affecting the design, calibration, and shipboard operation of the system are discussed in detail. Results of intercomparisons with other analytical techniques confirm the accuracy of the gas chromatographic method. Profiles of ΣCO2, O2, and N2 measured aboard ship are presented and discussed.

Weiss, RF, Bucher P, Craig H, Oeschger H.  1972.  Compositional variations of gases in temperate glaciers. Earth and Planetary Science Letters. 16:178-&.   10.1016/0012-821x(72)90186-0   AbstractWebsite

Concentrations of N2, O2, Ar and CO2 in ice from the Aletsch Glacier in the Bernese Alps have been measured by gas chromatography. Newly formed ice at the head of the glacier contains N2, O2 and Ar in roughly atmospheric proportions, whereas the CO2 content is ∼ 50 times greater than in air. Samples from the terminus of the glacier are considerably lower in total gas content, and are depleted in Ar and O2 and enriched in N2 with respect to air. The CO2 of this gas is ∼ 100 times greater than in air. Model calculations show that the N2-O2-Ar relationships are explained by the removal of these gases in solution in meltwater. In the case of CO2, the results indicate that only a small fraction of the CO2 in the ice is present in bubbles, the remainder being distributed within the ice matrix. Adsorption of atmospheric CO2 probably plays a role in determining the concentrations and distribution of CO2 in glacier ice.

Kroopnic.P, Weiss RF, Craig H.  1972.  Total CO2,13C, and dissolved oxygen -18O at GEOSECS II in the North Atlantic. Earth and Planetary Science Letters. 16:103-110.   10.1016/0012-821x(72)90242-7   AbstractWebsite

This paper presents profiles of ΣCO2, δ13C in ΣCO2, dissolved O2, and δ18O in dissolved O2, measured at Geosecs II in the North Atlantic. The O2 minimum at 1000 m is accompanied by a minimum in δ13C and a sharp maximum in δ18O; ΣCO2 increases downward through this layer with a slope change. All four parameters are remarkably uniform in the deep and bottom water below the O2 minimum, almost to the precision of measurement. Relative to data previously reported from this area of the Atlantic, our ΣCO2 values are 3% lower than those of Li et al. [10], and our δ13C values are up to 2‰ greater than those of Deuser and Hunt [12]. Also, our δ18O enrichments in dissolved O2 are very much less than Pacific values reported by Dole and coworkers [15]. All of these differences are attributed principally to bacterial O2 consumption during sample storage by previous workers, due to lack of, or inadequate, poisoning.In contrast to the North Atlantic, there is a very large gradient of dissolved O2 in the vertical profile of North Pacific Deep Water; however, if themean deep-water O2 concentration is compared with the uniform value in North Atlantic Deep Water, the O2 and ΣCO2 differences in North Atlantic and North Pacific Deep Water are essentially equimolar at 160 μm/kg. If 77% of deep-water O2 consumption is used for oxidation of organic carbon (the R-K-R “model plankton” value), the increase in ΣCO2 in Pacific deep water is about 25% due to dissolution of carbonate, and 75% due to oxidation of organic matter, in the vertical particulate flux. These proportions are in agreement with those estimated from alkalinity-ΣCO2 variations [10]. Our δ13C measurements in the Atlantic are quite consistent with the ΣCO2-O2-alkalinity variations between the Atlantic and Pacific deep water; thus the disagreement previously noted [14] is attributed to storage effects on δ13C measurements by previous workers, as noted above.

Craig, H, Weiss RF.  1971.  Dissolved gas saturation anomalies and excess helium in the ocean. Earth and Planetary Science Letters. 10:289-296.   10.1016/0012-821x(71)90033-1   AbstractWebsite

New solubility measurements have been made for helium and neon in seawater; the results (published elsewhere) show that neon is actually supersaturated in the ocean, rather than generally undersaturated as indicated by previous data. The pattern of He-Ne-Ar saturation anomalies, based on the new solubility data, shows the presence of an injected “atmospheric component” in Atlantic surface and deep waters and in Pacific deep waters, ranging from 0.5 to 1 ml of air (STP)/kg seawater. Nitrogen-argon relationships in the deep Pacific are also consistent with this effect. In addition to T and P, a third parameter is thus required for the study of saturation anomalies. The magnitude of the injected air fraction accounts for all of the “excess He” in Atlantic Deep Water and about 60% of the excess in the Pacific. The non-atmospheric excess He in the Pacific corresponds to an anomaly of 3%, presumably radiogenic and primordial helium.

Weiss, RF.  1971.  The effect of salinity on the solubility of argon in seawater. Deep-Sea Research. 18:225-230.   10.1016/0011-7471(71)90111-2   AbstractWebsite

New argon solubility measurements, made by two independent methods, confirm the use of the Setchénow relation in representing the salting-out of argon in seawater. No substantiation was found for the unusual salinity dependence implied by the argon solubility data of Murray and Riley (1970).

Weiss, RF.  1971.  Flushing characteristics of oceanographic sampling bottles. Deep-Sea Research. 18:653-656.   10.1016/0011-7471(71)90132-x   AbstractWebsite

The flushing characteristics of several types of oceanographic sampling bottles have been measured in a series of shipboard experiments using fluorescein dye. The results are consistent with a first-order model which may be used to calculate the flushing rate of a sampling bottle directly from its dimensions.

Weiss, RF.  1971.  Solubility of helium and neon in water and seawater. Journal of Chemical and Engineering Data. 16:235-241.   10.1021/je60049a019   AbstractWebsite

Sulfur hexafluoride (SF6) has been measured at Cape Grim since 1978 via a combination of in situ and flask measurements, including measurements on the Cape Grim air archive. The long-term growth rate of SF6 as observed at Cape Grim has increased from 0.1 ppt yr-1 in the late 1970s to 0.24 ppt yr-1 in the mid-1990s. Since then the growth rate has remained relatively constant at 0.23±0.02 ppt yr-1, indicating relatively constant global emissions (±10 %) since 1995. Pollution episodes at Cape Grim have been used to estimate regional (Melbourne and environs) and Australian emissions of SF6 at 3±1.5 and 15±7.5 tonnes yr-1 during 2001-2003.

Takahashi, T, Weiss RF, Culberson CH, Edmond JM, Hammond DE, Wong CS, Li Y-hui, Bainbridge AE.  1970.  A carbonate chemistry profile at the 1969 GEOSECS intercalibration station in the eastern Pacific Ocean. Journal of Geophysical Research. 75:7648-7666., Washington, DC, United States (USA): American Geophysical Union, Washington, DC   10.1029/JC075i036p07648   AbstractWebsite

To compare and evaluate measurements made by the various laboratories participating in the Geochemical Ocean Section Study (Geosecs), four carbonate chemistry parameters, pH, pCO2, alkalinity, and total dissolved CO2, as well as temperature and salinity were measured for samples collected at the Geosecs intercalibration station, 28°20′±07′N and 121°41′±02′W. The methods for measurement include the glass-calomel electrode pair for pH, the pH and the potentiometric acid titration methods for alkalinity, gas chromatographic, infrared and potentiometric acid titration method for total CO2, and the gas equilibrator-infrared method for pCO2. The alkalinity values measured by the pH method agree with the values measured by the potentiometric acid titration method within 1%, and the total CO2 values measured by the chromatographic method agree with the values measured by the potentiometric acid titration method within 2%. The observed 3 to 5% difference between the total CO2 values measured by the chromatographic and infrared methods is attributed to the biological alteration of the unpoisoned samples used for the infrared methods. When two of the four measured carbonate parameters were used to calculate the remaining two parameters, the calculated values are found to differ systematically from the measured values for those two parameters. Such a discrepancy can be eliminated if a 30% error in the second apparent dissociation constant for carbonic acid (K2′) is assumed.