Teacher's Report
Bill Hanshumaker, Educator at Sea

A small chimney at the base of Hell sulfide structure teeming with biota including several types of worms and gastropods.

Research on the deep-sea biological communities has many challenges, butis proceeding at a remarkable pace. Though we weren't even aware of this ecosystem prior to 1977, chemotrophic-based ecosystems have been found in every ocean and in an incredible array of environments. From hot vents to cold seeps, symbiotic creatures use hydrogen sulfide, methane, and even wood or dead whales as a primary energy source. Research into these environments is hampered by the extreme physical conditions. Initially, only tantalizing glimpses were possible through shipboard sampling "grabs" or the brief glimpses facilitated by submersibles such as the Alvin or remotely operated vehicles like ROPOS. These observational studies were usually documented with video recordings. But these are generally brief "snapshots" of animal behavior, and are often biased by the presence of the vehicle and, perhaps more importantly, the bright light in a normally pitch-black environment. Later, longer-term studies were conducted by equipment left on site to be retrieved on a subsequent expedition. While this provides beginning and end points for comparison, the intervening process is subject to both interpretation and speculation.

 

The top of Hell vent, a large high-temperature sulfide structure in the ASHES vent field. Notice the two black smoker chimneys at the top and colonies of tubeworms in the foreground .

In situ experiments conducted in the Thompson's labs use organisms brought up from the vent systems on the seafloor. They are generally short-term experiments since the animals eventually die from environmental stress. The transport up from the bottom, and the subsequent reduction in pressure, temperature increase, presence of light, and the lack of sulfide are all factors that can contribute to the animals' mortality. Experiments under high pressure, with the correct temperature and chemical conditions, can extend the time vent animals can live on board the ship. It is through this type of experimentation that important details about these unique animals are added to our body of knowledge.

Though this research process is difficult, there are important implications. Exploring symbiotic relationships has important manifestations in both the terrestrial and marine environments. Nitrogen fixation is an essential process mediated by bacteria for replenishing soils depleted by agriculture. From cows to termites, cellulose digestion is dependent on bacterial symbiants. The world's coral reef ecosystems would not be possible without their accompanying symbiotic algae. What we discover about symbiosis here at the deep-sea vents can have global ramifications.