Open AccessObservations of the volume flux of a seafloor hydrothermal plume using an acoustic imaging sonar
Author(s) -
Xu G.,
Jackson D. R.,
Bemis K. G.,
Rona P. A.
Publication year - 2013
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/ggge.20177
Subject(s) - plume , geology , seafloor spreading , flux (metallurgy) , volume (thermodynamics) , entrainment (biomusicology) , geophysics , hydrothermal vent , panache , seabed , hydrothermal circulation , oceanography , seismology , meteorology , physics , acoustics , metallurgy , materials science , quantum mechanics , rhythm
We present a 26 day time series (October 2010) of physical properties (volume flux, flow velocity, expansion rate) of a vigorous deep‐sea hydrothermal plume measured using our Cabled Observatory Vent Imaging Sonar (COVIS), which is connected to the Northeast Pacific Time Series Underwater Experiment Canada Cabled Observatory at the Main Endeavour Field on the Juan de Fuca Ridge. COVIS quantitatively monitors the initial buoyant rise of the plume from ∼ 5 m to ∼ 15 m above the vents. The time series exhibits temporal variations of the plume vertical volume flux ( 1.93 − 5.09 m 3 /s ), centerline vertical velocity component ( 0.11 − 0.24 m/s ) and expansion rate ( 0.082 − 0.21 m/m ); these variations have major spectral peaks at semidiurnal ( ∼ 2 cycle/day) and inertial oscillation ( ∼ 1.5 cycle/day) frequencies. The plume expansion rate (average ∼ 0.14 m/m ) is inversely proportional to the plume centerline vertical velocity component (coefficient of determinationR 2 ∼ 0.5 ). This inverse proportionality, as well as the semidiurnal frequency, indicates interaction between the plume and ambient ocean currents consistent with an entrainment of ambient seawater that increases with the magnitude of ambient currents. The inertial oscillations observed in the time series provide evidence for the influence of surface storms on the dynamics of hydrothermal plumes.