Next Generation Flux Meters For Enhanced Geochemical And High-Resolution Real-Time Benthic Flux Monitoring

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

P.I. Brown, Kevin (SIO) Proposal #: 0241998 Proposal Title: Next Generation Flux Meters For Enhanced Geochemical And High- Resolution Real-Time Benthic Flux Monitoring Project Summary This proposal will fund the development and construction of two prototype instruments that measure fluid flux in cold seep environments typical of continental margin areas. These instruments have an improved capability for long-term monitoring of flow transience, from tidal to multi-month scales, and geochemical sampling. The funds will be used to build and sea test (a) an electronic optical flow system (OFS) and (b) an enhanced osmotic flow meter system (CAT II) optimized for geochemical sampling (including noble gasses). These two benthic measurement devices can be used in conjunction or separately to measure fluid flow and fluxes of dissolved chemical species of interest in cold seep environments in the following ways: a) real-time fluid flow measurements when used in conjunction with satellite/buoy or cable observatories, b) measurement of transience in fluid flow from tidal to multi-month time scales, c) enhanced seabed coupling with remote collection chambers to negate current induced noise, d) reduced dead space in collection chamber improving response time for geochemical sampling, and e) increased chemical sampling ability with the addition of gas sampling capability for noble gases and methane. The PI will test the new instrumentation in lab simulations, offshore, and in situ through deployment in a seep area where other measurements are available for comparison. The Pi is also actively pursuing a test at a prototype deep-water, acoustically linked, moored-buoy seafloor observatory on the Nootka Fault off Vancouver Island in the Northeast Pacific. The~18 month long moored-buoy site is at an active area of seepage and the buoy will be fitted with an ocean bottom seismometer (OBS), an acoustic-doppler current profiler (ADCP), temperature, chemical sensors, bottom pressure and pore pressure sensors, different types of seep meters, and a conductivity-temperature-depth (CTD) sensor. These additional data will enable the PI to correlate his results with several different types fluid flow estimation methods (e.g. the pore pressure sensors) as well as with different potential impulses driving any transience in flow (i.e. tides, ocean currents and seismcity).