Ask an Explorer

Questions were sent to the science party during this expedition. Selected questions and answers are offered below.

Question from: Pat Wright

How do you know the age of the towers?

Answer by: Dr. Deborah Kelley, Co-Chief Scientist Lost City Expedition

Hi Pat,

There are a couple isotopes that we can use to date the chimneys at Lost City. We are lucky that the chimneys are made out of limestone because we can use carbon and uranium/thorium isotopes to date the towers. We have only analyzed a few samples so far, but these data show that the field has been active for at least 30,000 years. Perhaps, they have been active for much longer, however, so an important part of this expedition is collecting old-looking samples to see if we can extend this range.

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Question from: Phyllis

I guess I am amazed that this formation is news to you. This must mean that we know less about the ocean floor than I thought we did. I guess I get my expectations from submarine movies but I just assumed that we had good maps of most everything. What is keeping those maps from happening?

Answer by: Dr. Deborah Kelley, Co-Chief Scientist Lost City Expedition

You are definitely correct. The surface of Mars is mapped at higher resolution than our own ocean floor, which covers >70% of our planet! I believe that <10% of the seafloor is mapped at the resolution we need. For a while technology was the limiting factor, however we now have autonomous robotic vehicles that can map the seafloor at a resolution of a meter or less. What is very "cool" about these autonomous vehicles is that they also have smart chemical and thermal sensors and cameras so that they can be used to explore for submarine hot spring systems at the same time they are mapping the seafloor. We are mostly limited now because of funding.

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Question from: Lisa Cirincione, Rhode Island

I am working in Rhode Island on the TV control side of the Lost City Expedition. We were wondering where the word Telepresence originated and how old it was.

Answer by: Dr. Robert Ballard, Co-Chief Scientist Lost City Expedition

Dear Lisa,

I started using the word "tele-presence" in the early 1980's, but can't remember if I dreamed it up or heard the word before.

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Question from: Magda Trevino, teacher, School: Prepa Tec in Monterrey, Mexico, Departamento de Ciencias, Tecnologico de Monterrey, Campus Santa Catarina

What are the temperature, pressure, pH, and salinity conditions in Lost City?

Answer by: Dr. Mitch Schulte, Organic Geochemist

Thank you very much for your question. The conditions of the Lost City Vent Field are the subject of a great deal of study, and we're very interested in similarities and differences between this area and other hydrothermal areas.

The temperature of the waters in the Lost City vent field differs, depending on where the water comes from. The seawater in the area is between 7° and 10° C (44° to 50° F), and the vent fluids that emanate from the rocks and around the carbonate chimneys can be anywhere from slightly above the seawater temperature to as much as 90° C (194° F). It is easier to tell when there is a greater temperature difference between fluids. Much warmer water appears to shimmer, and because it is warmer it rises up through the cooler water.

The pressure varies with depth; for much of the area where the chimneys are found, the pressure is between about 70 and 85 bars (1030 to 1250 psi). For each meter (or about 3 feet) deeper you are, the pressure increases by about 1 bar (or 14.7 psi).

The pH of the seawater is around 8, but the pH of the vent fluid is significantly higher, between 9 and 11. The high pH values are similar to those found in things like ammonia or drain cleaner!

The salinity of the vent fluids is roughly the same as that of seawater; seawater generally has a salinity of about 35 parts per thousand (or 3.5%). There are other chemical differences between these waters and others that help make this a unique and fascinating place to explore.

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Question from: Lou Ann Kirby, Orlando, Florida

Are you seeing any marine life around the chimneys and if so, is it what you expected or is it unexpected?

Answer by: Tim Shank, Biology Department, Woods Hole Oceanographic Institution

Thank you for this interesting question. The larger marine life consists of grouper life fish that are up to 4 feet long. The other fish species we see swimming quickly around the spires is a two-foot long skinny fish called "kaupi" (pronounced "cow pie"). We also see two types of crabs- one is called geryonid, which can be up to 2 feet across (from leg tip to leg tip), and a smaller one that looks like a "sally-light foot" type that has yellow stripes on its legs. Many species of animals live directly on the chimneys. These include snails, worms, and shrimp-like animals called amphipods. We sampled these in 2003 and so we expected to see them here again this year. However, for the first time at Lost City we encountered a large (over 10 feet long) shark, much like a blue shark, that was patrolling around baited fish traps we left on the bottom. The traps were baited with cat food - we have come to learn over the years that crabs and fish like cat food. The shark may have liked the smell of cat food too as it slowly circled the traps for a while before swimming away into the darkness.

Thank you for your question and following our expedition.
Best wishes

Question from: Prof. Doutor Armando Almeida, Faculdade de Ciencias de Universidade de Lisboa, Departamento de Biologia Animal, Laboratorio Maritimo da Guia - IMAR, Cascais, Portugal

Can you confirm if the fish I saw at 28/07/2005 at +-18 h (Lisbon time) was a Polyprion americanus?

Answer by: Tim Shank, Biology Department, Woods Hole Oceanographic Institution

Yes, you must know your deep-sea fish well. The fish you saw is indeed the P. americanus wreckfish. People feel this fish is "inquisitive" of our activities, as it often circles our vehicle, coming within a few meters. My thinking is that the submersible lights attract migrating amphipods and sergestids (we often have a "swarm" following the lights after being on the bottom for a few hours), and the wreckfish may be coming around to prey on these crustaceans. We have yet to actually seen them feeding, but this explanation would explain their behavior.

Thank you for your question and hope you will keep following our expedition.
Best wishes

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Question from: Mike Dolph

Great site. Loaded with data, fabulous pictures, wonderful story. Is there something you expect to find? Who funds this research?

Answer by: Dr. Deborah Kelley, Co-chief Scientist, Lost City 2005

Hi Mike,
We expect to find new microorganisms and animals at the field during this expedition. The discovery of this field is relatively young. We found Lost City in 2000 and returned again to the site in 2003 (see http://www.lostcity.washington.edu ). Both the discovery cruise and follow-on cruise were funded by the National Science Foundation. There is still a lot to learn about the geologic, hydrothermal, and biological processes that have shaped this field. We hope to learn more about which microorganisms and animals are unique to Lost City, which ones are related to black smoker systems on the Mid-Atlantic Ridge, and which ones are "normal" for deep sea environments not directly associated with vents. We also hope to learn more about the origin of the gases (methane and hydrogen) and what governs differences in microbial communities within the field.

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Question from: Scott Troy, West High School Science Teacher, Denver Public Schools, Denver, Colorado

How does the extraordinary pressure on the seafloor affect the function of the hydrothermal fields?

Answer by: Deb Glickson, Geologist and PhD student, University of Washington

Hi Scott,
This is a great question and one that is important in many ways. Pressure (and temperature) in high temperature black smoker systems governs where boiling will occur on and within the seafloor. At 1 atmosphere pressure the boiling point of pure water is 100 degrees Celsius (212 degrees Fahrenheit). However, in seawater sodium chloride is an important component, which raises both the boiling point (where a vapor phase forms) and the critical point (where there is only one phase present that is neither liquid or vapor).

Seawater contains ~ 3.2 wt% sodium chloride (NaCl), such that the critical point is 407 degrees C (764 degrees Fahrenheit) and 298 bars (a pressure equal to 2980 meters of seawater). At temperatures and pressures less than this, seawater can undergo boiling in submarine systems. This means that seawater can boil at very high temperatures under the right conditions. This is particularly important on large volcanoes called seamounts that are common in some settings. Boiling is very common in these environments. During boiling many metals are concentrated in the vapor phase (gold, mercury, etc). The resultant black smoker chimneys are enriched in these metals.

In addition, pressure is important to microorganisms within submarine hot springs. Many black smoker environments are at pressures greater than 200 bars (200 x those we experience on the surface of the planet). It seems that in black smoker systems, pressure stabilizes certain components of the cell, which allows them to live at higher temperatures (the current upper temperature limit to life is 121 degrees Celsius, 249 degrees Fahrenheit!). Metabolic activity in some bacteria has been measured at greater than 10,000 atmospheres, equivalent to >10000 m water depth!

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Question from: Patricia Ludwig

Fascinating website. Sounds like an exciting and expensive research project. What are the pay-offs? How might your work make the world a better place?

Answer from: Dr. Deborah Kelley, Co-chief Scientist, Lost City 2005

One major motivation for this expedition was to provide the opportunity for the public to virtually participate in our oceanographic research in real time. The spectacular discovery of Lost City was a reminder of how little we have explored the ocean floor and offers a unique opportunity to share this natural wonder with the world. Our multi-media project is particularly dedicated to using this spectacular discovery as an educational tool to show young people how technology and different disciplines of natural sciences can be brought together to better understand the geological, chemical and biological processes that mold our Earth. This is then one of the most significant pay offs for this expedition - sparking the interest and enthusiasm for science and exploration in young people. We can't put a price tag on education and basic research. Although such an expedition is costly, the entire budget of research funded by the National Science Foundation is only a fraction of that of NASA. When we realize that our oceans cover over 70% of the Earth's surface and less than 10% of the seafloor has been explored, the price for exploration is negligible compared to how profound discoveries can change the way we view our planet

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Question from: Beth Sosin, New York City

I love seeing the video, thank you for all your incredible work. How did you find these hydrothermals and what do you hope this discovery will lead to?

Answer by: Dr. Mitch Schulte, Organic Geochemist

Beth,
The Lost City hydrothermal vent field was serendipitously discovered during a geological expedition in 2000 (see "Ghosts of the Abyss"). The chimneys suddenly came into view of underwater cameras and the crew was completely surprised and excited! We hope to learn about organisms that can live in an environment dominated by hydrogen and methane. This might suggest theories about the origin of life on this planet and possibly others such as Mars! Mars has rocks similar to the bedrock at Lost City.

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Question from: Tom Gardiner, Bainbridge Island, Washington

How common are these undersea vent fields and are there areas that have been discovered but not really explored as thoroughly as the "lost city?"

Answer by: Adelie Delacour, Geologist and Ph.D student

Tom,
There are over 200 hydrothermal vent fields. However, Lost City is completely unique because of the reaction that caused it to form. The other hydrothermal vent fields are similar to volcanic formation where magma heats sea water. At Lost City the heat is created by a reaction called serpentinization. (See the "Serpentinization" essay) When sea water reaches a mineral called olivine, an exothermic chemical reaction takes place and heat is released. That is what makes Lost City different than any other vent fields we know. However, we anticipate that Lost City is not the only vent field of this kind - we just haven't found others yet.

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