We have decided to release the Deep-ESP acoustically tomorrow morning, making this our final dive on the instrument. This was our last opportunity in this area to collect samples and ready the Deep-ESP for ascent.  We had a very busy schedule that included picking up the homer beacon and our experiments (Gulper incubation samples, and iSMACS - in Situ Mineral Associated Column Samplers), collecting tubeworms, sulfide samples, Niskin water samples and battery charging.   Once back on deck, we continued collecting lava samples with the rock crusher!
We had a great run with the Deep-ESP.  We sampled both diffuse vents and seawater in the vent field.  The diffuse vent was lower in salinity and oxygen and higher in temperature than the water in the vent field itself.  The Deep-ESP works kind of like your water filter, except we want what sticks on the filter, particulates and microorganisms found in seawater.  Some of the material collected was analyzed on the bottom of the ocean and some was preserved for laboratory analysis.  The fix that Brent made the other day allowed us to resume our analysis on the seafloor.  The microbial samples collected by the ESP for analysis in the lab will be used to investigate microbial communities involved in carbon cycling. 
This was an exciting day for iSmacs.  The three units were collected, and three more were deployed at the site just south of the hydrothermal vent chimney, Marshmallow.  We are hoping to have colleagues pick them up next month, or find a way to get back out here next summer to collect them.  The initial sampling of the 9 iSmacs looks promising.  Even in a few days some of the units had lots of microbial mat growth, which is evidence that diffuse hydrothermal fluid was indeed flowing through.  We have a temperature record for each iSmacs unit, and we had a good variety of cool (~5øC), warm (~14øC), and even a hot (~90øC) deployment.  Hopefully there was enough microbial colonization of the mineral grains to look at community differences, but we won't know that until a decent amount of lab work has happened.  We are interested in determining if different minerals tend to have different microbial communities, and whether or not the microbial community is functioning differently on different minerals.  We are particularly interested in carbon cycling in the vent environment, and would love to know if mineralogy affects which carbon fixation pathway is favored by the microbes.
Tune in tomorrow for Dave Clague's visit to the outer edges of the caldera.

Captions
D258_00_18_19_13: Here iSmacs #4 is being deployed at the base of Marshmallow chimney.  In the background #5 and #9 wait to be collected.
Mineral Tubes: White microbial mat on top of the mineral tubes inside one of the iSmacs.  This is evidence that vent fluid was passing through the tubes themselves, which was the goal of the iSmacs.
iSmacs10: This is what the inside of the iSmacs looks like after the cap has been removed.  There is also a temperature logger located below the mineral tubes.
Salinity.pdf:  Differences in salinity of the two sites (vent field and diffuse flow) the ESP sampled.  The diffuse flow is fresher (less saline water) and showed more variation than the surrounding seawater.  The waters also differed in temperature and their chemical composition.