J.P. Kellogg, R.E. McDuff, S.L. Hautala, F.R. Stahr

The Main Endeavour Field (MEF) has had a split personality since it was discovered.  The southern half of the field is regularly observed to be hotter and fresher than the northern half.  Differences lessened after the 1999 earthquake event, but the thermal and chemical gradient remains.  We examine CTD and MAVS data collected during surveys, designed to intersect the rising hydrothermal plume, conducted with the Autonomous Benthic Explorer (ABE) in 2000 and 2004.  By taking subsets of the data over known portions /structures of the field, we attribute fractional contributions to the whole field heat and salt fluxes.  Preliminary findings indicate that North MEF contributes ~90% and ~100% of the heat from MEF in 2000 and 2004 respectively.  It is clear from this that the majority of the MEF buoyancy flux is from North MEF even though the source fluids from South MEF are estimated to be initially more buoyant than those from North MEF.   Within North MEF, ~2/3 of the heat comes from the Grotto, Dante, Lobo area and ~1/4 from Hulk and Crypto.    We are currently striving towards a calculation of chemical flux that has predictive capabilities of the source characteristics.  With both years, it is possible to determine the intrafield spatial scales that fluxes of heat and salt are being efficiently mined.

The results presented are from the Flowmow and R2K funded Seabreeze research programs.  These results will be integral to discussing: influences from multiple sources to the total heat flux, methodology for measuring plume fluxes, site to site variations, relationships between plume magnitude and hydrothermal field size, and plume impacts on the overlying ocean.  We look forward to working with others towards the common goal of understanding the physical complexities of hydrothermal plumes.