Chief scientist leg 3
Antje Boetius
a.boetius.d at merian.briese-research.de
Really bad weather. Only tough sea - going MPI staff can stand this 24 hours a day. (For the movie click below on the link below. Source Gaby Schüssler)
Weblog 4

From temporal dynamics at depth to bad weather

On 1 November we carried out the first dive at our second working area, a deep water mud volcano. Some of us have been already here in 2003 and 2006 during other expeditions, to be intrigued by the strange mud flow landscapes at 1100 m water depth. Previously, sights of biology were rare on the central mud flows, so this time we are totally surprised to find a rich world of bacteria, fish, crabs, worms and bivalves on the seafloor.
Images from the central mud flows in 2006(right) and 2009 (left and middle). Note the difference in the seafloor morphology. In 2009 the hills are much smoother and populated by bacterial mats and animals. (Source MARUM M70/2 BIONIL 2006; MARUM MSM13/3 HOMER 2009)
This goes hand in hand with a strong reduction in activity of the mud and fluid flow, as indicated by the strongly decreased temperature gradients in the underlying seabed. The distribution of bacterial mats and the shape and morphology of the mud ripples indicate that most of the activity is situated north of the central mud flows, and that this is where enough reduced substances rise from depth to nourish abundant chemosynthetic life.

We use a combination of methods to identify the sites of the most active fluid flow, including geophysical tools, geochemical analyses and the visual observation of indicator organisms and habitat morphology. All of them indicate that the central area of this mud volcano have recovered from a probably quite large impact before 2006 to a rich diversity hot spot, fueled by the microbial conversion of reduced substances from depth.
Deployment of the heat flux corer (IFM GEOMAR). As to the size of the instrument: Tom Feseker (the guy in the red pants) is almost 2 m long and 1 m wide. (Source: Gabi Schüssler)
There are very few sites in the global deep ocean where scientists have been lucky enough with ship time and project funding, to return several times and to get an insight into temporal changes at the seafloor. These scientists generally find that the concept of a stable, continuous, impoverished and slow deep-sea environment lacking environmental disturbances and dynamic biological processes is a myth. As indicated already by the results from the sunken wood experiments from the first dives on this leg, and confirmed by the first overview dive to our second working area, many deep sea organisms appear able to use any opportunities of substrate and energy availability efficiently and immediately. Of course a mud volcano is not directly comparable to the wide desert-like abyssal ocean floor, but it is still astonishing to see the dramatic changes occurring on rather short time scales. But something else is operating on short time scales: The weather…
A beautiful rainbow between thunderstorms. (Source: Ralf Rehage)
After the dive on the 1 November, which made us so curious about the succession of life on the mud volcano since 2006, we were stopped already on the 2nd November by the abrupt weather change. Within a few hours, winds and waves got so strong that we had to cancel the dive on the 2nd November and could only go down without lift for a few hours in the afternoon of the 3rd November. Our alternative program was heat flux measurements, bathymetry and flare mapping, which made us even more wanting to dive again, as we could learn a lot about the outer structure of the mud volcano, which appears to host very interesting targets for further dives. We hope for better weather soon!

Antje Boetius
Left: The Marilyn Monroe effect: Due to wave actions, air is pressed through the moon pool and creates special hair-dos. (Model Viola Beier, Source Gabi Schüssler)

Right: Some are tougher than others: Viola Beier and Gabi Schüssler worked all day in the cold room when the storm hit us. (Source Christian Borowski)
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