The Benthic Fluid Flow sampler measures fluid flow at the sediment-water interface by monitoring the dilution of a chemical tracer injected into fluids at the seabed and collected in small-bore, capillary tubing by osmotic pumps. There are two types of flow meters installed on or near methane seeps at Southern Hydrate Ridge that are designed to measure fluids flowing at different speeds:
The “C” series of this instrument is a Chemical and Aqueous Transport (CAT) meter, and the “M” series of this instrument is a Multiple Orifice Sampler and Quantitative Injection Tracer Observer (MOSQUITO). Both instrument series are recovered annually, the fluids are analyzed for chemical tracer and major ion concentrations, and flow rates are calculated.
These instruments are critical to determining the flux of methane, hydrogen sulfide, and other gases that are emitted into the overlying ocean. Methane is especially important because it is a greenhouse gas, and it and other gases support novel microbial communities that thrive in and on the seafloor at these sites, and in the overlying ocean. The instruments allow time-series measurements to be made to examine changes in flow in response to seismic events, changes in the plumping system beneath hydrate ridge, and gas hydrate deposits in the subsurface.
The Core Instrument Analytical Results data repository contains processed analytical data and metadata for a subset of Cabled Array instruments that collect fluid or particulate samples that are brought back to shore and analyzed in a laboratory. Numerical and other processed analytical results are generally provided in spreadsheet form. Associated metadata files including analytical protocols, sampling and recovery notes, and sample log files are presented in .pdf format. As-deployed images of instruments are provided in .jpg format, with image metadata summarized in spreadsheet-based catalogs.