Alvin Dive 3362
26 February, 1999
Cindy Van Dover (transcript,
Eric Bergmanis (transcript),
Dudley Foster
This dive began with a ½ h geology transect with sampling, beginning west of the axis to
cross a contact en route to the ARGO-Rehu Marka site. At this Rehu-Marka site, there is
evidence of a greatly declining vent system, with dead serpulids, dead mussels but still with
extensive anemone beds. From the Rehu-Marka waypoint, we headed approximately 010 to Mkr
24 where we found diffuse flow and live mussels in discrete patches among more extensive
patches of dead and dying mussels in cracks. We attempted 3 pot samples in patches of 100%
live mussels (2 of which worked) and we filled one box with a scooped sample of 100% live
mussels for a comparison of these two sampling methods (x = 1180, y = 243, z = 2581).
Maximum temperature in the mussel patch was 9.5C. We selected a second site for mussel
sampling, about 110 m NW of the first sample, within this same field (x = 1149, y = 276, z =
2581). Maximum temperature within the patch sampled was 5.5C. We collected 3 pots here
plus one box sample (but the box sample contains mussels by one's and two's rather than
scoops). Although there were 2 mussel boxes remaining, the loss of the scoop made it doubtful
that filling these would be a very satisfactory use of dive time. Given that another dive would be
made in this area, the decision was made at 1330 h to divert an additional 1.5 hr of the dive to
geology, with perhaps a trade for some bio samples in this area on a subsequent geology dive.
Sample Locations: