High precision gas analysers for CO 2, CH 4, CO, N 2O and δ 13C-in-CO 2 (CRDS and FTIR, see methods) were installed approximately 20 m from the lower (Grand Arch) entrance and sequentially analysed air sampled once per hour drawn along tubing from four locations in the cave (Fig.
We also measured cave air-temperature, air-flow, air-pressure, drip-rate, and drip pH continuously for 3 years from September 2012 to July 2015. 1), represents a well-ventilated tourist cave hosting several tours per day. Our continuous data for CH 4, CO 2, δ 13C-in-CO 2, Rn, CO, and N 2O trace gases from Chifley Cave (Fig. CO 2 sources that would be expected to show antithetical behaviour relative to CH 4 are ground air 7 and the overlying soil gas, where CO 2 is increased by plant root and microbial respiration and CH 4 is depleted by microbial oxidation. CO 2 has several potential sources, including breath from cave visitors, ground air 7, speleothem growth 8, 9 and karst soil gas 10. CO 2 is enhanced relative to the external ambient atmosphere, to as high as 10,000 ppm in summer but remains near external ambient in winter. However, an in-situ steady-state model is inconsistent with our observations of strong diel and seasonal bias in CO 2, CH 4 and other trace gases.Ĭave CO 2 variations are strongly anti-correlated with those of CH 4. A methanotrophic bacterial oxidation mechanism was first proposed to account for rapid methane loss over a few hours 1, 2, 5 in opposition to a recently proposed radiolytic CH 4 destruction mechanism 4.Ī steady-state model of in-situ depletion of methane by cave dwelling methanotrophs or radiolytic destruction by ions derived from radon decay might be expected from the year round constant cave air temperature ± 2 ☌. Disentangling cause and effect of cave gas variations by tracing sources and sinks has identified seasonal speleothem growth bias, with implied palaeo-climate record bias.Ĭave methane depletion is near universal for 44 caves reported 1, 2, 3, 4, 5, 6. Unexpected seasonal bias in our cave CH 4 depletion record is explained by a three-step process involving methanotrophy in aerobic karst soil above the cave, summer transport of soil-gas into the cave through epikarst, followed by further cave CH 4 depletion. Extreme bacterial selection due to the absence of alternate carbon sources for growth in the cave environment has resulted in an extremely high proportion 2–12% of methanotrophs in the total bacteria present. Methanotrophic bacteria, some newly-discovered, rapidly consume methane on cave surfaces and in external karst soils with lifetimes in the cave of a few hours. Here, we report a continuous 3-year record of cave methane and other trace gases in Jenolan Caves, Australia which shows a seasonal cycle of extreme CH 4 depletion, from ambient ~1,775 ppb to near zero during summer and to ~800 ppb in winter.
SUM OF DEPENDENT DATA DATA LOGGER PRO PRO
You can copy and paste to create one file and then import the master CSV back into Logger Pro 3.Methane concentration in caves is commonly much lower than the external atmosphere, yet the cave CH 4 depletion causal mechanism is contested and dynamic links to external diurnal and seasonal temperature cycles unknown. For multiple files, export to CSV and open the files in a spreadsheet program (such as Microsoft Excel). Note: The instructions above assume that all the data are in the same Logger Pro file. You can also delete empty columns once you’ve copied the data. Now you can copy and paste cells from one column to another. Choose Import From > CSV from the File menu and select your.In Logger Pro, choose Export As > CSV from the File menu.You can use this workaround in order to copy and paste the cells as needed. This is useful in many cases, but makes it tricky to aggregate multiple data sets into one. Logger Pro 3 data collection is designed so that data are locked and cannot be modified.
How do I combine sensor data collected in different data sets or runs into one data set in Logger Pro?
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