Shipboard life continues during and after the Alvin dives. Rebecca maintains a normal schedule and is at work at her paintings during the day when most lab inhabitants catch up on their sleep. After a series of Beggiatoa- influenced works that reflect the orange/yellow/white palette and the irregular outlines of colorful microbial mats, she is in a blue “archaeal” phase that demands her full concentration.
The daylight agrees well with Dir deBeer, here at his microprofiling station where he has determined the chemical gradients in numerous microbial mat cores and reference cores. These cores were subsequently frozen away at -80C for high-resolution spatial and structural analysis of organic compounds at the Hinrichs lab at Bremen University. The goal is to superimpose and correlate microprofiler gradients that delineate the habitat characteristics, and molecular structures, which reflect the microbial biomass of dominant populations in the gradient habitat.
Complementary work in high-resolution organic matter structural analysis [in larger cm-thick sediment layers, without the spatial component on microsensor scale] will take place at Oldenburg University, in a collaboration of several groups at the Institute for the Chemistry and Biology of the Marine Environment. Here Thorsten Brinkhoff is slicing a sediment core for the Oldenburg group.
In the same lab, UNC graduate student Chris Chambers, the bench neighbor of MPI student Marit van Erk, is sampling sediment cores for his biogeochemical project, determining sulfate and sulfide gradients of sediments; these data will be used to assess seawater inmixing into the hydrothermal sediments, but they will also provide biogeochemical characterizations for the WHOI project, cultivations and activities of hydrocarbon-degrading fungi in Guaymas Basin sediments. Next to bacteria and archaea, fungi – generally single-celled microscopic forms – belong to the diverse group of organisms that degrade hydrocarbons in nature.
On the morning of Nov. 27, after the last Alvin dive, the long-anticipated T-Shirt sale of the Alvin and Sentry groups is finally starting. The T-Shirts are customized and printed at the Howlingbird Shop in Falmouth, MA, and the latest Alvin- and Sentry-themed designs are sold exclusively here on the ship for the benefit of your hard-working Alvin and Sentry teams. Get your Christmas presents now!
Sentry rests after many all-night missions, after surpassing all expectations; this smart AUV has sniffed out the methane plumes, redox signals and thermal anomalies that define the hydrothermal plumes rising from the vents almost 100 meters into the water column. In doing so we have now 3D reconstructions of the major hydrothermal plumes across the southern Guaymas vent field. The major vents, for example Northern Cathedral and Big Pagoda, have their own very localized plumes that emerge from a single source. Other hydrothermal areas have a more diffuse, almost communal plume that emerges from many smaller sources, for example in the Mat Mound Massif.
Zac Berkovitz is leading the Sentry team on this cruise; they have all done a fabulous job and used Sentry to full capacity: chemical and thermal sensing; bottom photo surveys, bathymetry, and subbottom seismics, all wrapped into one package. There is nothing like Sentry! To top it off, Zac is now rewriting detailed instructions for the Sentry data package – a guide to Sentry-generated data files and the programs that are required to open and process them. It is almost heretical to say, especially for an Alvin aficionado, but it would be possible to run a very successful survey cruise in the Gulf of California only with Sentry and the occasional water column sampling trip by CTD.
Now, back to work! This blog page is uploaded in the morning of the 28th. We have one more day in the lab, to be used for packing and stowing, before arrival in Manzanillo in the morning of the 29th.