Logbook: September 4, 2006

Position: 45°55.0'N, 129°59.5'W
Axial Volcano

One of the most beautiful vent sites on the 1998 lava flow is at marker N3. The large diffuse vent area is covered with a blue mat made of small single-celled organisms called ciliates. We have never seen such an extensive carpet of this unusual blue mat anywhere else in the world! (click image for larger view)

Today ROPOS dive R1014 is conducting vent fluid sampling at vents on the southern part of the 1998 lava flow.

The NeMO seafloor observatory at Axial Volcano has many aspects and wide-ranging goals, but they all involve scientific measurements to try to understand the spatial variability on the volcano and the temporal evolution of chemical, physical, geological and biological processes.

Hydrothermal systems are created by the interaction of seawater with hot ocean crust and they are by nature highly dynamic. By monitoring the temperature and composition of hot springs at different locations, we can make inferences about how conditions are changing beneath the seafloor. Everything is connected, so the geological structure controls how water can pass through the volcano, where it exits at hot springs, and how hot water mixes with cold seawater both below and at the seafloor to generate livable habitat for microbes and hydrothermal vent fauna. A simple example of this connectedness is that nearly all of the known hot springs at Axial are located very close to the caldera rim faults.

The connection between microbiological communities and chemical/physical conditions of the hydrothermal habitat is one of the major research areas at NeMO, and it is a very complex problem. One of the tools we use is a specialized sampling instrument (Hydrothermal Fluid and Particle Sampler, commonly referred to as “the beast”) developed at PMEL that pumps hydrothermal fluid through a manifold while measuring temperature, and directs the fluid into sample containers or through filters to concentrate microbes. We thereby get coordinated chemical/microbiological information about different vent sites around the volcano. We have been doing this kind of sampling as a time-series at specific vent sites, but also in exploration mode, where we locate vents all around the volcano and characterize their chemistry and microbiological communities. So far we have found that there are distinct populations of microbes that live in different vent habitats and that microbial communities at specific vents changed over time following the 1998 volcanic eruption at Axial. We are currently trying new statistical approaches to looking at combined microbiological and chemical data to understand the ecology of this volcano.