Teacher-at-Sea – January 4, 2007
By Anne Leary/Special to the Minuteman
This January 10th, Clarke Middle School Life Science teacher Carolyn Sheild will join a consortium of scientists embarking upon an expedition aboard the Woods Hole Oceanographic Institution ship Atlantis with its deep-diving submarine, the Alvin, to the East Pacific Rise off the coast of Mexico, home to 600 highly adapted species. Chosen as 2007 Teacher-at-Sea for SEAS, the web-based, NSF-funded science education program, Sheild will field questions from classrooms in the “Ask-a-Scientist” forum, update the research being performed on the Atlantis and describe her impressions of the life of a scientist aboard ship to students around the country via the website, http://www.ridge2000.org/seas .

Recently, Woods Hole scientist and chief scientific officer of the expedition, Dr. Timothy Shank, visited the students at Clarke Middle School and explained the significance of the research conducted at the site. Using video shot during previous dives of the Alvin submarine at the East Pacific Rise, he enthralled students with an underwater world of curious creatures who hover, swarm, snatch, wriggle, skitter and scoot through an environment that has perplexed and intrigued scientists ever since its discovery in 1977. That environment, he explained, was formed by seawater sinking through cracks generated by the movement of tectonic plates in the ocean floor. The water is superheated by the earth’s magma, creating underwater hot springs, or hydrothermal vents, which release a hot, mineral-rich stew that supports an ecosystem specifically adapted to life in this sunless environment. “These organisms that take advantage of these fundamental planetary processes – the evolution of life and how it has occurred here—that is what drives me to study this place,” he says.

Shank reminded students that the process of photosynthesis – where green plants use the sun’s energy to convert carbon dioxide into food and oxygen– is necessary for life on earth, yet impossible in the sunless depths of the ocean. Residents of the Rise use chemosynthesis instead. Utilizing hydrogen sulfide, which is spewed forth from the vents in abundance, organisms of the East Pacific Rise have entered into a mutually beneficial arrangement with sulfur-loving bacteria, the first and most crucial residents to colonize the vent sites. The bacteria living inside many of the animals at the vent sites use the chemical energy from the hydrogen sulfide to make food for their hosts, while the animals provide a comfy spot for the bacteria to call home. Harvard microbiologist and Lexington resident Dr. Colleen Cavanaugh is credited with uncovering the symbiotic relationship between these organisms. Cavanaugh postulates that this chemosynthetic symbiotic relationship may be how life first evolved on Earth.

For Clarke’s Sheild, this chance to join the expedition represents an extraordinary opportunity for a teacher and she is grateful for the funding from both the National Science Foundation and the Lexington Education Foundation. She looks forward to both understanding in greater depth what the scientists are learning while at sea and also helping to convey this to her students and students across the country through the website: “Not only the content, but also the process – how the science is being done,” she says.

“To have the opportunity to go in the submarine, and actually see the creatures I’ve only read about and seen in movies, that will be a thrill,” Sheild says. A thrill for her, and, through the internet connection, for all the school children and residents of Lexington and beyond.