Mail Buoy

January 12, 2013

Hello, Atlantis!

We hope you have had a successful start to your mission. After viewing your lab set-up video and reading the daily updates, it appears as though you have. We were also intrigued to find out how many languages the scientists aboard the Atlantis speak! Most impressive!

We have two questions. If you have time to answer them, we are most interested to know:

1. Have you made any recent discoveries? If so, how many and what are they?
2. Are the tubeworms you study linked to cancer research?

Many thanks,

Valerie Smith
Grade 6
Morse Pond School
Falmouth, Mass.

Hi Valerie,

It’s great to hear from you and your class. Thank you for your questions and for following our expedition. Things are indeed going very well. Having so many different nationalities on board the ship is great. We learn form each other and there are so many stories to be shared. It feels like we are making the world a little smaller this way.

As for your questions, we have actually already made a few discoveries. First, the vent site we are mostly studying, called “Crab Spa,” is still active. We were hoping that would be the case, but did not know for sure, as the last visit was almost two years ago. On the other hand, a vent site we were hoping to sample as well, “Trick-or-Treat,” is not active anymore. We also found a new site that we have named “Teddy Bear,” because the bacteria there look like long pieces of fur stuck to the rocks. It's quite an extensive area of venting, and we are studying its biology and chemistry in some detail to learn more about it. There are no tubeworms or mussels around it. So maybe it became active only quite recently. Further, we documented some activity around M-vent, which was a very active black smoker before it became extinct after the undersea volcanic eruption at the end of 2005. Also, the experiments in the lab are going very well, and we can already say that the microbes are quite active and consume chemicals rather rapidly. However, most of the discoveries are waiting to be made once we have completely analyzed our samples back in the labs on shore.

Your second question is a good one too. The study of the tubeworms is not directly linked to cancer research, but better understanding the interaction of the animal with its symbiotic bacteria might lead to some insights that could be used in the biomedical field. How the tubeworm acquires the symbionts is a complicated process, involving the production of chemicals used for cell recognition and signaling. In general, there is a huge potential for discovering new bioactive compounds at vents. Vents are highly productive ecosystems, and there are lots of organisms that either work together or compete with each other and that produce intriguing chemicals involved in these interactions.

Please say hi to all the kids in your class for me, don’t hesitate to send other questions. I look forward to visit the class after the cruise.

All the best,

Stefan

Dear Mr. Sievert, dear Crew,

The Leistungskurs Biologie from the Gymnasium Ramstein-Miesenbach is wishing you good luck for your expedition and all the very best for the New Year!

Sincerely the LK and Esther Sternheim.

We have the following questions to you: 

By thinking about how the first organisms could start to settle down on a “newborn” hydrothermal vent, we asked ourselves how the animals or their larvae are able to survive in the ocean as long as they haven’t found a hydrothermal vent. What do they live from? Where do they get their energy from?

Dear Esther and LK students,

Many organisms produce eggs that have large deposits of reserve substances such as fats or sugars. When they turn into larvae, they can still use these substances much like an unborn chicken feeds on their egg yolks. Currents carry the floating larvae away and allow them, if they are lucky, to find a new vent site to settle. It is unknown how they recognize or are attracted by new vent sites.

Sincerely, 
Horst Felbeck

If just a few bacteria settle down on a new hydrothermal vent, there are only the genes of these individuals in the gene pool that build up the whole population that is going to live at this vent. So is it possible, that each vent might have in a way a “specific” species of bacteria?

Dear Esther and LK students:

That's a very good thought process, but the gene pool at the vents may progress over time. The second part of your question is true, however. At different vents, different species of bacteria can be dominant, depending on the conditions there. Temperature is a big factor, for example. Slight changes in temperature affect molecules such as proteins inside a cell. Think of it this way: If you take a raw egg, which is mostly made of proteins, it's soft and runny. But if you heat it up, the proteins will completely change and form a solid mass. The same thing happens to bacteria at vents that aren't adapted to high heat. If a vent is particularly hot, only microbes that can withstand that heat will survive, so you'll see a larger population of those species living there. Another factor is a vent's fluid chemistry. Each vent may spew fluids that have a different amount of hydrogen, oxygen, sulfur dioxide, and other chemicals. There are a number of species of bacteria at the vents that need specific chemicals to survive, so depending on the chemistry, you'll find different species of bacteria that are dominant. 

Best,
Costa Vetriani

In science we've been learning about parts of the cell. I know that some microbes are anaerobic. I was wondering if cells that don't use oxygen have mitochondria? If not, how do they break down food for energy?

Thank you for answering my question!

Emilia
7th grade, Clarke Middle School
Lexington, Mass.

Dear Emilia,

Thank you for your question. This is a good one!

Mitochondria break down our food with oxygen to release the energy in the food, and we use this energy to do everything that we do. Without them, the world we know would not include animals, plants, or even many types of microbes.

The process of using oxygen to get energy in mitochondria is kind of like how a fire combines oxygen with wood, which releases energy as heat and light. Of course, the process in our mitochondria is more controlled, and you can check a biology textbook for more details if you're curious.

But back to your question. Oxygen is not the only chemical that can be used to get energy from food, and microbes can use an incredible number of chemicals in place of oxygen to get energy. Some examples of chemicals that microbes use instead of oxygen are nitrate, sulfate, iron, and manganese.

These microbes do not have mitochondria. Mitochondria are a special type of organelle that are only found in organisms that use oxygen all of the time, including humans. The way the anaerobic microbes break down the food is actually very similar to mitochondria. They use a lot of the same proteins, but simply do not use oxygen to breathe. You can think of the microbes that grow anaerobically as simply “breathing” nitrate, sulfate, or iron instead of oxygen.

An interesting fact is that the microbes that use other chemicals instead of oxygen to break down their food get much less energy out of the food than microbes that use oxygen. From a microbe's perspective, they need to eat a lot more food for dinner to get the same amount of energy as their peers that grow with oxygen.

Because of this, most of the microbes that can grow without oxygen are found where oxygen levels are very low, because the ones that can use oxygen gain more energy from their food and grow faster. So nowadays, the anaerobic microbes are restricted to anaerobic regions such as stinky anoxic muds, cow's stomachs, and some hydrothermal vent environments.

In the past, before plants appeared on Earth, there was no oxygen in the atmosphere, so these anaerobic microbes were the only ones that were around. When microscopic plants evolved and began producing oxygen, organisms evolved to take advantage of this newly formed oxygen. Scientists who study evolution think that the mitochondria's ancestor was one of these organisms, which at some point combined with another cell to form the ancestor of all “higher” organisms such as plants and animals.

Hope that helps you understand better!

Jesse McNichol