Summer CO2 evasion from streams and rivers in the Kolyma River basin, north-east Siberia

Inland water systems are generally supersaturated in carbon dioxide (CO2) and are increasingly recognized as playing an important role in the global carbon cycle. The Arctic may be particularly important in this respect, given the abundance of inland waters and carbon contained in Arctic soils; however, a lack of trace gas measurements from small streams in the Arctic currently limits this understanding.We investigated the spatial variability of CO2 evasion during the summer low-flow period from streams and rivers in the northern portion of the Kolyma River basin in north-eastern Siberia. To this end, partial pressure of carbon dioxide (pCO2) and gas exchange velocities (k) were measured at a diverse set of streams and rivers to calculate CO2 evasion fluxes. We combined these CO2 evasion estimates with satellite remote sensing and geographic information system techniques to calculate total areal CO2 emissions. Our results show that small streams are substantial sources of atmospheric CO2 owing to high pCO2 and k, despite being a small portion of total inland water surface area. In contrast, large rivers were generally near equilibrium with atmospheric CO2. Extrapolating our findings across the Panteleikha-Ambolikha sub-watersheds demonstrated that small streams play a major role in CO2 evasion, accounting for 86% of the total summer CO2 emissions from inland waters within these two sub-watersheds. Further expansion of these regional CO2 emission estimates across time and space will be critical to accurately quantify and understand the role of Arctic streams and rivers in the global carbon budget

Mechanical vibrations of pendant liquid droplets

A simple optical deflection technique was used to monitor the vibrations of microlitre pendant droplets of deuterium oxide, formamide, and 1,1,2,2-tetrabromoethane. Droplets of different volumes of each liquid were suspended from the end of a microlitre pipette and vibrated using a small puff of nitrogen gas. A laser was passed through the droplets and the scattered light was collected using a photodiode. Vibration of the droplets resulted in the motion of the scattered beam and time-dependent intensity variations were recorded using the photodiode. These time- dependent variations were Fourier transformed and the frequencies and widths of the mechanical droplet resonances were extracted. A simple model of vibrations in pendant/sessile drops was used to relate these parameters to the surface tension, density and viscosity of the liquid droplets. The surface tension values obtained from this method were found to be in good agreement with results obtained using the standard pendant drop technique. Damping of capillary waves on pendant drops was shown to be similar to that observed for deep liquid baths and the kinematic viscosities obtained were in agreement with literature values for all three liquids studied

Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Hesperides Cruise in the Atlantic Ocean

This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO{sub 2}), total alkalinity (TALK), and pH at hydrographic stations during the R/V Hesperides oceanographic cruise in the Atlantic Ocean (Section A5). Conducted as part of the Work Ocean Circulation Experiment (WOCE), the cruise began in Cadiz, Spain, on July 14, 1992, and ended in Miami, Florida, on August 15, 1992. Measurements made along WOCE Section A5 included CTD pressure, temperature, salinity, and oxygen; and bottle salinity, oxygen, phosphate, nitrate, nitrite, silicate, TCO{sub 2}, TALK, and pH. The TALK, TCO{sub 2}, and pH were determined from titrations of seawater collected at 33 stations. The titration systems for measuring TALK and TCO{sub 2} were calibrated in the laboratory with certified reference materials (CRMs) before the cruise to ensure traceable results. Standard reference seawater provided by Andrew Dickson of Scripps Institution of Oceanography (SIO) was used at sea to monitor the performance of the titration systems. The results agree with the laboratory results to {+-} 2 {micro}mol/kg for TALK and {+-} 1 {micro}mol/kg for TCO{sub 2}. The titration systems used to measure pH were calibrated with TRIS seawater buffers prepared in the laboratory and measured with an H{sub 2}, Pt/AgCl, Ag electrode. The initial electromotive force (emf) of the titrations was used to determine the pH. The values of pH are thought to be reliable to {+-} 0.01 and are internally consistent with the measured values of TALK and TCO{sub 2} to {+-} 7 {micro}mol/kg. The measured carbon dioxide system parameters have been used to calculate the in situ values of the fugacity of CO{sub 2} (fCO{sub 2}) for the surface water. The surface results are briefly discussed

8.1 - Physico-Chemical Controls on Seawater

The physical–chemical controls on seawater can be attributed to the effect that the composition of the major components have on the thermodynamics and kinetics of processes in the oceans. In this chapter, an earlier review on the experimental and modeling work that has been done on how the major components of seawater control rates and equilibria of processes in the oceans has been updated. The effect of major components on the physical–chemical properties of seawater, the carbonate system in the oceans and the effect of ocean acidification on speciation of metals in seawater has been emphasized

Continual measurement of the total inorganic carbon in surface seawater

An automated sampling and analysis system was developed to determine the total inorganic carbon (TCO 2) in seawater. Measurements are performed on subsamples taken from the shipboard flowing seawater line. The flowing TCO 2 system (FTCO 2) automatically acidifies and strips the CO 2 out of a known volume of sea water and determines the concentration by integrating the infra red (IR) absorbance. Laboratory results have demonstrated an analytical precision of 2–5 μM in TCO 2 for this system. Intercomparison of TCO 2 measurements with the FTCO 2 system and the SOMMA (single operator multimetabolic analyzer) agreed within their respective uncertainties. The TCO 2 in surface seawater was determined continually on the flowing seawater line aboard the R/V Thompson in the Arabian Sea. The average difference between the TCO 2 determined on surface seawater with the flowing system and the SOMMA was 6.5±8.7 μM. Measurements made with the flowing system on CRMs agreed to ±3 μM with the assigned value. TCO 2 in surface waters in the Arabian Sea varied by as much as 40 μM on short spatial and temporal scales. Although the accuracy of the present design of the FTCO 2 system is not as good as the SOMMA, the surface TCO 2 variability with time and space is captured with the FTCO 2 system and is completely missed by discrete measurements made on CTD casts. Continual measurements of TCO 2 will be valuable in characterizing the temporal and spatial changes in the carbon dioxide system in surface ocean waters

PVT properties of concentrated aqueous electrolytes. 7. The volumes of mixing of the reciprocal salt pairs KCl, K/sub 2/SO/sub 4/, NaCl, and Na/sub 2/SO/sub 4/ at 25/sup 0/C and I = 1. 5 m

The densities of mixtures of the six possible combinations of the salts KCl, NaCl, K/sub 2/SO/sub 4/, Na/sub 2/SO/sub 4/ have been determined at constant ionic strength (I = 1.5 m) and 25/sup 0/C. The results have been used to determine the volume of mixing (..delta..V/sub m/) for these salts. The values of ..delta..V/sub m/ have been fit to equations of the form ..delta..V/sub m/ = y/sub 2/y/sub 3/I/sup 2/(upsilon/sub 0/ + upsilon/sub 1/(1 - 2y/sub 3/)) where y/sub i/ is the ionic strength fraction of salt I, and upsilon/sub 0/ and upsilon/sub 1/ are parameters related to the interaction of like charged ions. The cross-square rule was found to hold within the experimental error of the measurements