Updates From Sea | Cruise 2007
January 11th
By Eric Simms, Education Outreach Coordinator
If a volcanic eruption happens 2500 meters (over 8,000 feet) below the ocean's surface, will anyone know about it? Actually, yes. And the team of scientists on this research cruise are heading out to the scene of the action to learn more!
Photo © 2006 D. Fornari & M. Tolstoy
What Happened? In April 2006, scientists in the Ridge 2000 research community were excited to discover that a large volcanic eruption happened deep on the seafloor in the eastern Pacific Ocean, right in the center of their long-term study site. Scientists discovered the eruption when their ocean bottom seismometers, devices used to record earthquakes, failed to respond (see image at left). After a little sleuthing, they determined that the instrument was partially buried in fresh lava. Why was this particular eruption so exciting? One reason is that large eruptions do not occur very often - the last one in this same area happened fifteen years ago - and this one may have taken place only 3 months earlier in January 2006. The other reason is that several scientists in the community who monitor vent fluid chemistry and earthquake activity at the site had noticed significant changes and had predicted that something should happen soon - and they were right!
Photo © 2006 D. Fornari & J. Cowen
Background Most deep-sea volcanic eruptions happen along the mid-ocean ridge, where plates that make up the Earth's crust are slowly spreading apart in opposite directions. Occasionally, magma from below the crust erupts upwards between the two plates and flows outward away from the ridge. This lava contributes to the renewal of the Earth's crust as it cools and hardens. The new crust also provides new places for seafloor biological communities to form. The image to the left shows fresh lava (darker and glassy) overlying an older lava flow.
What does our science party want to find out? The scientists in our science party represent a range of disciplines (microbiology, geochemistry, ecology, and evolutionary biology). While some scientists (like geologists) are interested in how eruptions occur, our team wants to know what happens to the community of organisms (microbes and animals) living in such an environment. Specifically, they are studying how the animals and microbes, as well as the water chemistry, in the deep sea change over time after an eruption. Large eruptions of new lava can cover areas of the ocean floor, burying many of the animals and microbes found there and leaving only bare rock. Within less than a year, however, new communities of organisms often develop. The scientists want to study how (and when) new microbes and animals arrive at the eruption site. They want to know what temperatures and chemicals might attract new organisms, and what do these new arrivals need to survive.
Change over time: Our team is also interested in understanding how the types of microbes and animals at the site will change over time. Scientists have been studying this location for fifteen years since the last major eruption, and have documented the patterns of change in this community (see BioGeoTransect and the SEAS Activity 4: Change Over Time). The recent eruption offers us a unique opportunity to see how a community starts anew. I'm excited to be joining the team helping to report their work to you through these log entries.
Photo © 2007 Eric Simms
Several research cruises have visited the eruption site since May 2006, and our cruise builds on what has been found so far. Our ship, the R/V Atlantis, left the port of Manzanillo, Mexico on the morning of January 10, and should arrive at the East Pacific Rise study site to start scientific operations on January 12th. During the cruise, the research submersible Alvin will be used to explore the seafloor during the day, while at night other instruments will collect water samples and images of the seafloor. Stay tuned for more updates about the research happening on the cruise, and what it is like to experience life at sea.
And be sure to register for "Ask-a-Scientist" - you can submit questions that our scientists on board will answer on this site!
