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May 28, 2003 What do you enjoy most about being on a research vehicle? What do you miss most while on the research vehicle? Thank you, Hello Josh and Jessica, thanks for your question. I took it around to a variety of members of the group here, and here's what they said: Dave Shuster, scientist: Ian Yurdin, DiveDiscover photographer: Dave Dubois, Shipboard Scientific Services Group Technician: Kate Buckman, scientist Blee Williams, Alvin pilot Dan Scheirer, Co-chief scientist My question involves how the coral skeleton can indicate climate changes. I read the "About the Cruise" and Hot Topics about it and there is reference to "chemistry" of the skeleton and how that relates to the chemistry of the water, but can you be more specific? How can the coral skeleton indicate whether there was cold, deep water flowing when they lived? (I imagine it has something to do with the CaCO3 of the skeleton and CO2 in the atmosphere being incorporated into the ocean?) Could you please expand on the paragraphs below from the "About the Cruise" section as far as the biochemistry so I can better understand your mission and explain it to my students. Thanks so much and good luck discovering! "The corals' skeletons can provide crucial clues to the history of Earth's climate, which is what the cruise is all about. We hope to find out how and why the planet's climate has rapidly shifted from cold to warm periods, and to use that information to predict how it might change in the future. "The corals' skeletons are rich repositories of environmental information. The biochemical composition of their skeletons is different if they grow in different water conditions. And water conditions change as Earth's climate does. Like undersea tape recorders, individual corals at different depths in the ocean have recorded how Earth's climate has changed through time." Here's a partial answer, from the expedition's chief scientist, Jess Adkins: The most important piece of chemistry we're interested in is the C14 (radiocarbon) age of the water. The plot below shows that modern, living corals record the same C14 age as the water in which they grow. Click here to see a figure that illustrates this. Why waters have different C14 ages will be covered in an upcoming Hot Topic about radiocarbon aging. But briefly, once water sinks from the surface, it no longer can exchange CO2 with the atmosphere, and it therefore loses C14 by radio decay. The longer water spends below the surface, the older its age and the less C14 it has. Therefore, the radiocarbon content of the deep ocean is a measure of the overturning time of the deep sea. This is a critical component of the ocean's heat transport, and therefore climate generally. How likely is it that Alvin would discover the wreck of a vessel in its search for coral within the seamounts? Irene P. Atney DSV Alvin Expedition Leader Patrick Hickey responds: Every time we make a dive in ALVIN, there is a chance we will come across some obstacle on the sea floor. We (ALVIN Operations Group) are specifically prohibited by our operations restrictions from diving the submersible in an area of known entanglements. Our dives on the Titanic, for example, required special permission to carry out. Wrecks definitely fall into this category. We do not, however, have a magic map showing all the wrecks of the world and have, occasionally, come across bottom debris in various forms. An old warplane off San Diego, jettisoned munitions off New Jersey, a whale carcass off Oregon. If something is found, it is then up to the pilot in command of the dive to report his find and then to determine if it is safe to continue or to abort the dive. Because of all the sea traffic that has occurred in
this area, especially WWII convoys, coming across a
wreck is possible, though unlikely. The ocean is a
large place and stumbling onto an old warship, freighter
or submarine would be like winning a lottery. You always
hear about it happening to someone else, but never
to you.
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