Mail Buoy

January 16 responses:

What will this whole entire expedition help us/teach us 20 years from now and what knowledge would it give us?

Brittany, Memorial High School, Eau Claire, Wis. 

Dear Brittany,

This oceanographic expedition is focused on enhancing our understanding of microbial processes at deep-sea vents. Scientists involved are studying the interplay between evolution and microbial diversity and functionality. In other words, this research will tell us how microorganisms use the energy released in deep-sea vents to grow and evolve in an extremely hostile habitat. On this cruise, scientists are sampling fluids from the vents that contain lots of microbes, and are conducting experiments onboard the ship to learn the function and metabolism of the organisms under high pressures. They are also monitoring the vent fluids’ chemical composition. Some of the earliest life forms on Earth were microbes similar to the ones that live at vents—so this sort of research can teach us not only about the origins of life on our planet, but also about life that may have formed in similar conditions on other planets.

Best,
Dionysis Foustoukos

When did the microbes evolve to become producers at vents?

Eugene
Ms. Sheild's classes at Clarke Middle School, Lexington, Mass.

Dear Eugene,

We don't really know when the microbes that live at deep-sea vents evolved. That's a very difficult question to answer. What we do know, or at least what we hypothesize based on several lines of evidence, is that some vent microbes are close relatives of very ancient bacteria that might have lived on our planet when there was no oxygen, and the atmosphere was filled with volcanic gases.

Some of these organisms can live off hydrogen, sulfur, and carbon dioxide, which are all products of volcanic activity. Unlike most primary producers on land (plants) and in the surface ocean (algae), they don't need light to make a living.

Our ability to grow these microbes in the laboratory allows us to study their lifestyle (physiology and metabolism) and origins (phylogeny).

All the best,
Costa Vetriani

Do you find it ironic that the Atlantis serves sushi and other fish-related foods?

Emmet
Ms. Sheild's classes at Clarke Middle School, Lexington, Mass.

Hiya Emmet,

Being out at sea for long periods of time, sometimes we get bored and cast out fishing lines to see what we can drag aboard. Down here at 9° North, there are lots of mahi and squid, and some yellowfin tunas roaming about, so it's a good day when we can pull a fresh fish right out of the water. Sailors have traditionally respected and revered the ocean, being at the whim of the elements for such long stretches of time, so enjoying the fruits of its harvest comes naturally to us.

When we order fish from our vendors in various ports, I take the time to find a reputable salesperson who takes care and pride in providing sustainably caught seafood. This means more work for the galley, but it's the responsible thing to do instead of ordering unscrupulously farmed, foreign-sourced fish.

Living at sea for most of the year gives us a good knowledge of where our fish come from and respect for proper methods used in the fishing industry, so I would say it's not so much ironic to be serving seafood on a ship, but rather appropriate.

Brendon Todd
Cook, R/V Atlantis

How do you get microbes' DNA from them (because they are very small)?

Shirin
Ms. Sheild's classes at Clarke Middle School, Lexington, Mass.

Hi Shirin,

Thanks for your question. You are right that microbes are very small, and indeed it's very difficult to get DNA out of a single microbe. That's why we usually extract DNA from a large number of them. In every drop of water or gram of sediment there are millions of microbes, sometimes more. We extract DNA from a few grams of sediment or liters of water, so we are sure there are plenty of microbes to get enough DNA.

There are several methods to extract DNA, but all of them essentially involve breaking microbial cells open to release the DNA, separating the DNA from the debris of the broken cells, and then purifying the extracted DNA. I personally like to use a solution of SDS (a kind of soap) and heat to break the cells, a compound called phenol (which degrades proteins and lipids) to separate DNA from the cell debris using centrifugation, and then ethanol to clean the DNA. A similar protocol can be used in science class to extract DNA from strawberries. Ask your teacher to help you carry out the experiment!

All the best,
Donato Giovannelli