The
blue mat and tube worm colonies covering the seafloor at the N3 site
in the 1998 lava flow area. Samples of blue mat were suctioned and
water samples were taken at this site (see other image
in log).
Today's dive, R856, was primarily for water sampling
at the vent sites located on the 1998 lava flow on the east side of the
caldera. High and low temperature hydrothermal fluids were sampled as
well as samples dedicated to analyzing their gas contents, primarily helium.
Fluid samples were obtained at Marker N3, Cloud vent, Marker 33, Village
and Castle vents. Blue mat material was sampled at N3 and Village vent
sites. This year, Castle vent had a vigorous flow with temperature readings
near 200degC, the highest in the 1998 lava flow area found so far this
year.
Dive
R856 ended early to recover the NeMO Net BPR that we just deployed yesterday.
The real-time satellite communication with the instrument indicated a
problem with the BPR's data transmission. During the night, a CTD tow
was made over the northern portion of the 1998 lava flow and bathymetric
mapping of the nearby area continued.
