Nov 26. Alvin dive 5001

The last dive is again a PIT dive, Anthony Tarantino as driving instructor and Todd Litke as trainee. But who is the science observer? Since this cruise is shorter than usual, it will not be possible to get all Alvin novices into the sub. The person with the strongest claim would be Virginia Edgcomb, associate scientist at WHOI and experienced seagoing microbial oceanographer; she is also a PI on a NSF project attached to this cruise. Yet, there are three equally deserving young scientists – Marit van Erk, Viola Krukenberg and Vivian Mara – who should all have the opportunity. Now human generosity and the Greek gods intervene in the most miraculous fashion. Virginia Edgcomb gives up her dive, since she would not enjoy it as much as one of the younger scientists would. Thus, Virginia and your blogger come up with a design for divine intervention. Three Alvin cups are prepared by yours truly and shrunk during dive 5000, showing an Riftia bouquet, an octopus and a microbial mat. The cups are wrapped and each candidate chooses one. The microbial mat wins. Now, Poseidon must have reached up from the ocean and intervened in favor of a daughter of Hellas: Vivian draws the microbial mat!

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Vivian and Virginia graciously pose for the paparazzi. Virginia Edgcomb is Vivian’s postdoctoral advisor at WHOI; Vivian comes originally from the beautiful Island of Crete, birthplace of Zeus, and represents Greece on the roster of Alvin dives, perhaps for the first time in Alvin history.

Vivian and her pilots loose no time in collecting a last haul of hydrothermal sediment cores for the science crew. This collection is important, because these cores can be worked up without having the clock of the next Alvin dive already ticking. Every biogeochemistry crew on the Atlantis appreciates this conclusion to an expedition..

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Fortunately, Vivian and her team also have time for a visit at Northern Cathedral Hill to admire the Riftia gardens, one last time. It is like being admitted to a very exclusive National Park that allows only a few dozen people in, even in busy years.  The view through the porthole and its massive window, and past the robot arm, also illustrates the distance; the view is not immediate but necessarily constrained; human observers can reach this place only through the equivalent of space age technology. While every space vehicle has to accommodate the pressure difference of 1 atmosphere inside and none outside, Alvin has to withstand 200 atmospheres outside at the bottom of Guaymas Basin. Its current limit is 450 atmospheres and 4500 meters; the next upgrade will bring all systems to 6500 meters and 650 atmospheres. After this dive, Alvin will participate in one more cruise – a training cruise for aspiring PIs – and then returns to Woods Hole for the upgrade.

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A last look at the hydrothermal landscape of Guaymas Basin, its oil-soaked sediments, microbial mats and shimmering waters. It never remains the same, as the hydrothermal fluids are constantly finding new flow paths through the sediments. The next visitors to Guaymas Basin will again find new hot spots, new sampling locations, and new microbial surprises and discoveries.

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Unlike the 2001 Space odyssey, the Alvin 5001 dive team – from left, Vivian, Anthony and Todd – returns to Earth in good health and spirits. Alvin’s many computer systems do not develop their own devious plans.

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Back on the Atlantis, Vivian has stories to tell, and she does so with energy and panache!

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After Alvin returns, the Atlantis stays on station just long enough to complete one last CTD cast of the water column and the hydrothermal plume at Northern Cathedral Hill; then at around 10 pm we are off and steam southeast, towards Manzanillo. The two days of transit will get very busy!

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