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Read questions and answers in the Mail Buoy» December 1, 2011 Hi I'm Sonya and I'm in Ms. Shield's class. I am really interested in this expedition you guys are on and I was wondering how we evolved so that we need oxygen to survive, when most biologists agree that life may have started in environments with little or no oxygen at all like DHABs. Also why did this process happen? Sonya P. We are all very happy about your deep interest in our research and this expedition. The question about the evolution of life is a central question in biology. When life evolved, more than three billion years ago, the atmospheric conditions were completely different from what we have today. Oxygen did not exist on Earth for a very long time. The first organisms to appear on our planet were bacteria. Higher organisms (the ones that have a nucleus and organelles) evolved only about 1.5 billion years ago. At that time, so-called cyanobacteria had already produced some oxygen. The atmosphere had about 1% of the present oxygen level. But most of the deeper oceans were still anoxic (without oxygen) and sulfidic (even though not all scientists agree with this). Thus, (bacterial) life started without oxygen. The higher (eukaryote) life may either have started under very low oxygen concentrations, or depending on the source of its origin, even under sub- or anoxic conditions. This is a very exciting field of research and with the tools that we have available today, it is a great challenge and very much fun to work in this field. As to your question "why did this process happen," this is very difficult (if at all) to answer. Science can provide some pretty good answers to the "how," but not to the why. Evolution may be just a lucky chain of coincidences. Dr. Thorsten Stoeck My name is Stavros, I am 8 years old and I have two questions: Why you call this vehicle system Jason/Medea? Jason was the leader of the Argonauts. Scientists and crew are the Argonauts and Jason is a hero? Stavros M. Unlike the often gruesome and violent events in mythology, our Jason and Medea have had a successful and adventuresome "career" exploring the ocean depths as we modern day "Argonauts" continue to search for answers to the secrets of the deep. 2. As I can understand you take samples from 3,500 meters under the sea where it is totally dark, without oxygen, and saltier-than-normal seawater. How can you keep the same conditions when you take the samples to the laboratory? The organisms are still the same? They don’t change out in the air? Dear Stavros, We can relatively easily account for some of the factors like darkness and lack of oxygen. During sample processing, we try to avoid exposing the organisms to light. For example, we have blackened sample bottles that do not allow light to penetrate into the samples. Likewise, we do not expose the organisms to atmospheric conditions by using some sophisticated gas systems during sample processing. Salt is not a big issue, because we know the exact ion composition of the sample water and can mimic this in the lab. But what we cannot account for is pressure. At 3,500 meters below the sea, we have an extremely high pressure, which is about 350 times higher than atmospheric pressure that we are exposed to. Larger organisms like fish and deep-sea squid die when you transport them from the deep to the ocean surface. Maybe this is also true for the protists we study. We don't know yet, how big the loss of cells is when we bring deep-sea water to the surface. But this is something we will find out during this project. For the first time, we have a newly designed sampler that enables us to collect and preserve samples immediately at depth. If we now compare such samples with samples that were only preserved after they were retrieved from the deep to the ship, we know how many cells don't survive the journey to the surface. From previous expeditions we know that many cells don't mind the pressure difference (compared to larger organisms, single celled organisms have no gas-filled organelles, which are the main reason for deep-sea organisms to die when brought to the surface) and we still find many thousand protists in one liter of deep-sea water. Dr. Thorsten Stoeck How do you choose where to go for expeditions? Don't other oceans have brines too? Also, why would you want to study the things that are in the brine? Elizabeth W. I would like to know the following: What created the ancient subterranean salt deposits? What kind of salts they contain (except NaCl)? Conditions in DHABs are representative of the conditions of early Earth and could favor the emergence of biomolecules and the beginning of life? Antonis M. If DHABS are found throughout the world, would the geochemistry, sediments, and organisms found in the bathtub ring be similar to that of other regions? Hannah B. Each expedition has specific scientific quests. And in oceanography some of them, like the DHABs mission, require sampling in specific sites of the world's oceans. Now, the research vessel Atlantis made it all the way to the Mediterranean DHABs, after Dr. Edgcomb had proposed this research, simply because DHABs are known to exist only in the Mediterranean. Organisms that live in the DHABs are very important for learning new insights on biology and the limits of life and also how the ocean works. Elizabeth, please go through some of the previous answers and you will find the details about the importance of these microbes Antonis, you should also refer to the "What are the DHABs" of the main page of this "Dive and Discover” site. The conditions of early Earth seem to include high temperatures, and temperature in the DHABs are about 13 to 15 °C. But the organisms living in these brines are surely of interest in the evolution of life, so gaining any knowledge on them is important. Hannah, your question is very intriguing but until we find any new DHABs, we cannot tell how different or similar will they be with the Mediterranean ones. Keeping in mind that, for example, that Discovery basin is quite different from Urania Basin, and they are very close to each other, then yes, any new DHAB could be surprisingly different to the ones we know! Cell Tracker is a chemical substance that is absorbed by living organisms, so if there are any living organisms in the brines, they will incorporate it, and then in the lab we will be able to see this colored organisms under the microscope. This substance works irrelevantly of high pressure and cold temperature. Dr. Konstantinos Kormas Are all the oceans salty because the tectonic plates shifted and released the salt, or is there another reason? Will B. Dear Will, The second source of ions is very closely related to what you mentioned. It is not the tectonic plate shift per se that delivers ions to the ocean water, but something closely related to this. Maybe you have heard about hydrothermal vents at the crest of oceanic ridges. Among other things, they discharge dissolved minerals. Seawater seeps into the rocks of the oceanic crust. As the temperature of this seeping seawater rises, it dissolves these minerals from the subterranean rocks. Through exit points like hydrothermal vents, this water eventually finds its way back into the ocean carrying all the dissolved minerals with it, and, thus, contributing to a salty ocean. Dr. Thorsten Stoeck How long does it take to make/prepare the Jason? Michael B. It typically takes 10 to 12 hours to reconfigure the vehicle for a science dive. It took more than three years to design and build Jason. The Jason team How does the RNAlater preserve the protists? Do you freeze the whole protist or just copy the RNA? Peter L. Brian Z. These are questions I was asking myself for quite some time when RNAlater hit the market. For us, it has revolutionized our fieldwork with nucleic acids, specifically with RNA. RNA is a very unstable molecule. Unlike DNA, which consists of a double strand and is very stable, RNA is a single-stranded molecule and therefore very prone to degradation by an enzyme. This enzyme is simply everywhere, from the tips of your fingers to air, soil and water. RNAlater, as we found out, is basically an ammonium salt in a very high concentration. This inhibits the activity of the degrading enzyme. After the addition of RNAlater to a collection of cells (protists), we do freeze the samples as soon as we can. Because freezing further inhibits degrading enzymes. Now you may ask: why then don't we stick to freezing only? Because even at very low temperatures, enzymes are still active. Though with a strongly decreased activity. But after a period of several months, enzymes will have degraded all the RNA, even in the deep-freezer. Therefore, we use the RNAlater. I hope I could answer your questions satisfactorily. Dr. Thorsten Stoeck Two questions, one answer: How long was the ship in lockdown? John and Matt Tess and Bella We were in lockdown for about 12 hours, from around 10 p.m. on Friday night until a little after 10 the following morning. When we first learned that so many strangers would be coming onto the ship, we were a little afraid mainly because we didn’t know for sure who they were. We had heard stories of pirates taking over ships. But we watched them come aboard (on closed circuit TV) and we saw how polite and calm they were. And they really needed our help. We were also in the very capable hands of Capt. Colburn and his crew, and the members of the Jason team who were out on deck. So it wasn’t so scary after all—just a very interesting way to start a research cruise! Thank you for writing, What was the best thing about the Jason? Alex S. Three things about Jason made it the perfect tool to get the sediment samples we needed. One is that with Jason, we could take cores from exactly the spot we wanted to. With an instrument like a multicorer, you can’t control exactly where the sampler will land. Related to this is that with Jason, the scientist and the pilot see exactly the same view, so the scientist can point to a spot and say, “Let’s get a sample from right there.” That’s not possible in a human-occupied vehicle like Alvin, because in Alvin the portholes are so small that only one person at a time can look out of each one. That means the scientist and the pilot (who manipulates the arms that gather the samples) never see the same thing at the same time. The third great thing about Jason is that it sends back high-quality photos and video of everything it does. Those are invaluable later when we study the cores. Thanks for writing, In the video, there is a tiny white dot in the distance which disapears. Do you have an idea of what it is? Also, could the amount of light given off by Jason affect any of the data? Mary Kate J. Without seeing exactly what white dot you are referring to, it is hard to answer this question, but I suspect that the white dot you saw is a piece of "marine snow." As Jason descends through the water column you see lots of this stuff. It consists of organic material (bits and pieces of organisms, feces of organisms, etc.) that are covered with bacteria that are degrading this organic material. Marine snow is also populated by protists that are also grazing on the organic material and on the bacteria. The lights from Jason do bother some of the fish and other animals. Others get very curious about the lights and come check them out. I doubt they have much of an effect on the microbes that we are studying. Cheers,
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