The last few days have featured absolutely beautiful weather at our research site with sunny skies and nearly calm winds making the sea surface nearly smooth as glass. During this time we have been hard at work collecting more fluid and rock samples on the seafloor and the biologists have started to kick their research into high gear.

We are studying the heat-loving microbes (thermophiles) that are associated with the hot spring sites we will be visiting during this research cruise. It may be a surprise to you, but most of the biodiversity of life is microscopic, yet it has been estimated that as little as 1% of this diversity has been described and studied. So one of the goals of our research is to explore what new thermophiles remain hidden in this poorly explored part of our planet.

Fig. 1: Sulfide chimneys on the deep sea floor

Fig. 2: Porous layers in a sulfide chimney sample collected by Jason

Fig. 3: Hydrogen-oxidizing microbes

Fig. 4: Mixed fermentative culture of microbes

At deep-sea hot springs, most of the thermophiles attach and grow in the actively forming sulfide chimneys. These chimney’s form as the cold oxygenated seawater mixes with the very high temperature fluid (~ 360ºC at Rainbow), and the minerals precipitate out of solution. Initially the chimneys are very porous, so the temperature gradients across the chimney walls are extreme (from 4°C to 360ºC), but also provide many different habitats for thermophiles to colonize. (Figs. 1 and 2).

We collect these sulfides and analyze the thermophiles that have made this warm environment their home..  We then use DNA techniques (stay tuned for another update) to describe the diversity of thermophiles in these samples (Julie is doing this on our cruise) and we try to grow some of the thermophiles in a ‘simulated’ environment in ovens (stay tuned for the update on “what thermophiles eat”).  Tatiana, Ilya, Anna-Louise and Gilbert are all very busy growing thermophiles that grow at 90, 80 and 70ºC. We already have several of the thermophiles growing (Figs 3 and 4).

In addition to collecting sulfides we are also interested in knowing when and where the thermophiles colonize newly formed sulfides. A few days ago we deployed an instrument (that we will use multiple times in a research cruise scheduled for 2009), that is an array of thermocouples attached to a titanium frame. The frame is placed directly on a hot vent (Fig. 5) in the hopes that a chimney will grow up through the frame. The frame provides the ‘scaffold’ around which the sulfide minerals can deposit (Fig. 6). These initial mineral deposits are very soft and are like mud, and being able to collect this material is not an easy task! Lucky for us, the Jason pilots are very skilled, and this deployment of the ‘thermocouple’ array was very successful. We will analyze this sample to see if any thermophiles had colonized the array.

There are several other microbial-related experiments going on, and we’ll update you on those as we start moving to other sites. This evening we’re reluctantly leaving the Rainbow vent fields. After spending the past week exploring this part of the seafloor 2300 meters below the surface, it seems like a familiar place. Some areas are as familiar as Old Faithful is to those of us who have visited Yellowstone National Park multiple times. But sadly we need to leave, and it will most likely be many years before any of us will ever return to enjoy this exciting and unusual deep-sea vent site.

Microbiologist Ilya Kublanov (center) and other members of the scientific team stand ready to retrieve samples from Jason

Fig. 5: Deploying the thermocouple array on a hot vent

Fig. 6: Sulfide minerals attached to the array

Microbiologists (from left to right) Tatiana Slepova, Julie Kirshtein, Anna-Louise Reysenbach, and Gilbert Flores study chimney material sampled by Jason

Yet another beautiful sunset

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