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Do you think there is a cure for cancer or AIDS in the ocean?
I will have to say this is one of the strangest questions that we have received about our work at Hess Deep. Although there is certainly nothing at present to suggest that we are going to discover cures for serious illnesses on the seafloor, your question raises some interesting issues. For example, did you know that the major drug companies are very interested in harvesting microscopic organisms that live cracks deep in the seafloor? We know so little about these tiny critters and their genetic make-up that there are all sorts of possibilities that they can be used to produce important drugs and medicines.
I think this just highlights how little we really know about the bottom of the ocean even as we move into the 21st century. I like to say that every time we go to the seafloor we learn something new and exciting. At this point I would also say that we are just learning to learn about things down there. Just learning what questions to ask. A cure for AIDS? Who knows?
I recently read about the oxygen minimun layer. Between 600 to 800 meters the O2 is at its lowest. Beyond this depth the O2 begins to rise until the sea floor is reached. Is this true? Do you have any more information on this subject? What is the current paradigm on this phenomenon?
The oxygen minimum occurs roughly between 0.5 and 1.5 kilometers. It tends to correspond to the water depths where seawater undergoes a relatively rapid increase in density, known as the pycnocline. Waters above the O2 minimum have more oxygen because it is mixed into the water from the atmosphere by chemical diffusion across the sea surface and waves. It is also produced by photosynthesizing marine plants, most importantly phytoplankton. These are the primary ways oxygen gets into seawater. The reason waters below the minimum have more oxygen is because it is carried there by deep ocean currents. These currents consist of cold waters that once were at the sea surface at the Earth's north and south poles. There the surface waters are cooled to the point that they become denser than normal seawater and sink. New surface waters move into replace the sinking waters. But the deeper waters move away from the poles, spilling across the floors of the ocean basins at lower latitudes. The increase in oxygen below the minimum is one of the key pieces of evidence as to where these currents (the speeds of which can and have been measured) came from. Finally, the cause for the oxygen minimum is believed to be the decay of dead organic matter. Most of the marine life in the deep ocean lives in the water depths that receive light (about 0 to 100 meters). The photosynthesizing marine plants in this region are eaten by animals such as fish, which are in turn eaten by larger animals such as sharks and whales, which also can eat each other. However, when a plant or animal dies or is eaten, not all of its body parts get consumed. Waste is also produced. This unused organic matter sinks toward the seafloor, decaying as it goes. And the decay consumes oxygen, producing carbon in its place (essentially, decay is the reverse of photosynthesis). It appears that much of this decaying organic matter may accumulate in the pycnocline. This is because as the seawater density increases, the rate at which the decaying organic matter sinks slows. Thus a pile-up of decaying organic matter in the pyconocline may be the cause for the oxygen minimum.
In addition to whatever other answers you may receive, you can learn more about the present thinking on the O2 minimum in many college oceanography textbooks. For example, you might try Garrison's Introduction to Oceanography.
What is the greatesst discovery or research that had come from this exploration?
The relative significance of various results of our project depend on your point of view. There were many very important details that we were able to document and different investigators on the cruise were very excited about different specific things. Overall, the most important general conclusion of our work is that the internal structure of lava flows and dikes that feed them in the uppermost oceanic crust is much more complicated than has been previously thought. Earlier ideas of the architecture of the oceanic crust have come mostly from very indirect paths - marine seismic data, comparisons with similar rocks on land, etc. Our direct observations by-pass all this indirect reasoning and document a considerably more interesting situation. As you will see in the web site, we found many faults and highly fractured intervals in the crust and also many places where originally vertical dikes had been tilted and where originally horizontal lava flows had been tilted. The fracturing and tilting reflect dramatic processes that must be operating under mid-ocean ridge spreading centers. There is little hint of this at spreading centers because so much lava buries the evidence. Our results force us to reconsider what is going on under these spreading centers where all the oceanic crust on our planet is being produced.
Thanks for your interest in our project!
What is a hydrothermal vent and what are rifts?
A rift is just a giant crack in the Earth. They commonly form in continents as they break up and as new ocean areas that form as the contiental pieces move apart. The East African Rift is a famous one, but there are many others, too. As the Atlantic ocean began to open between North America and Europe and Africa, it started out as a narrow rift valley. It has taken about 150 million years for the Atlantic to grow to its current width. Rifts also occur in the oceans, mostly along mid-ocean ridge spreading centers where new ocean floor is constantly being created. These submarine mountain ranges are split by the same large cracks. Mid-ocean ridges are long mountain chains with many faults and volcanoes where new ocean floor is created. At mid-ocean ridges (and just about everywhere there are active volcanoes!) water seeps down into cracks in the rocks. In the oceans this is seawater, but on land it is groundwater from rain, surface run-off and streams. As the water is heated near the hot areas around a volcano, it expands and moves upward. It comes out of cracks in rocks - sometimes very forcefully, as in geysers. The general term for places where hot water is being driven out of the Earth by volcanic heat is "hydrothermal vents." As water moves out of the rocks, more water is sucked in from surrounding areas to replenish the system. In this way a very large amount of water is circulated through these "hydrothermal systems." As the water circulates, minerals are commonly deposited resulting in metallic ore deposits (gold, copper, zinc, etc.). Hydrothermal vents on mid-ocean ridges are especially interesting because they can circulate a volume equal to all of the oceans through rocks on the seafloor in only about 10,000 years - that is very fast in geological terms. Chemical reactions with the rocks change the chemistry of the seawater. In addition, strange clusters of specially adapted animals live around the vents like a deep sea oasis. These animals live under the huge pressure of more than a mile of ocean water, with no light (and no photosynthetic plants as on the Earth's surface) and by eating bacteria that essentially live off the rocks.
Hope these will answer your questions. Thanks again for emailing us!
I am doing a report on how the ocean floor changes. I have learned about the movement of the tectonic plates and the spreading of the sea floor. What else changes the geological features of the sea floor? How does anything that humans do effect the topography? What kind of effect does the movment have on the shape of the ocean floor?
Thanks for your questions about our research cruise to the Hess Deep rift. Let me try to answer your questions: What else [besides seafloor spreading] changes the geological features of the sea floor? Not much. Most of the seafloor is shaped as it is formed near mid-ocean ridge spreading centers. Typically it has a kind of "corduroy" pattern of linear hills called "abyssal hills" that form parallel to the spreading center. If you look at a seafloor map you will see this pattern. In the old parts of the Pacific ocean floor there are many volcanoes that have erupted on top of the seafloor. These come from hot places under the lithosphere plates we call "hot spots." Hawaii is a great example of a big one, but there are many smaller ones too. Besides these processes, the only other thing that is happening is the slow burial under sedimentary material. This is generally very slow as the tiny shells of animals that live and die in the sea pile up on the seafloor. Near the edges of continents erosion adds much more sedimentary material. How does anything that humans do effect the topography? It doesn't. The effects of civilization on the deep sea are minimal. On the bottom we sometimes see some trash- probably from ships sailing on the surface, but that is about it. If greenhouse gasses produced by burning fossil fuels should cause global warming, then glaciers could melt and climatic patterns could shift, causing more rapid erosion. That would have an effect, but still not a large one where the deep sea is concerned. What kind of effect does the movment have on the shape of the ocean floor? As lithosphere plates move they remain fairly rigid. Very little change takes place unless the plate moves over a hot spot as mentioned above, or until it approaches a subduction zone where it is bent and shoved under the edge of a continent (like the western edge of South America) or a volcanic island chain (like Japan).
Hope this will answer your questions. Nice to hear from you.
Dr.Jeff Karson, I was very excited to learn of your career choice and particularly your project. If I had known you would have grown up to be a rockhound I would have shared some of my rocks with you when we were younger. Congratulations to you and those who participated! I am reporting news of your adventure to Medina Gem & Mineral Society in May and will also pass information to the Medina High School Science Deptartment. PS: It would be great if you could advise of future projects.
Thanks for your note. It is a kick to hear from someone back in my home town! Glad you enjoyed tagging along on our project electronically. We will try to keep you informed of other projects in the future. For the time being though we have a tremendous amount of work to do on our Hess Deep data.
I am doing a research project on how bacteria affects the growth of rust. One of my experiments in this project is to see how salt water will affect the results of my experiment. I have recently found that the rust on the Titanic was helped to form from bacteria. I would like to know the approximate concentration of salt at the Titanic depth.
Since the Hess Deep cruise is in a much different area than the North Atlantic Ocean resting place of the ocean liner HMS Titanic, it took me a while to try and answer your question. Fortunately, there are specialists aboard who have long memories and also know how to find information in the R/V Atlantis's library. From those sources, I would say that the salt concentration in the Titanic's environs is about 34 parts per thousand. Good luck with your research project!
My class's recent Time Magazine for Kids had a story about giant squid. Since they live in depths of several miles below, my students are worried about your encountering one of them and what would happen if you did. Any words of comfort on this? And, is it possible?
Thank your class for its concern, but your students should be reassured that Alvin faces no danger from giant squid. The pilots who "fly" the Alvin, as they call traveling up and down miles of deep ocean, say they have never encountered giant squid, though lesser sized squid are plentiful enough in the waters above Hess Deep. If a giant squid did meet the Alvin, its operators are confindent that all aboard would be protected by it's tough titanium hull, which can withstand tremendous pressures.
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