Descent to the bottom of the sea – B. Neal

Dr. Greg Rouse is an expert in the wild and fantastical life forms that live at the bottom of the sea. He can glance at a tiny worm writhing in a microscope image and identify it as easily as you would know your own brother across the room. He has been a traveler in deep and cold ocean bottom all around the world, from Greenland to Australia, sometimes actually going down himself into the darkness in submarines or by diving, and sometimes “visiting” by means of dropping down drags and scoops, and bringing up the residents and their worlds for investigation in the laboratory. On this voyage he has dropped a box core sampling device to 1500 feet, nearly a third of a mile, and brought a perfect square of bottom mud up the surface for examination, somewhat like lifting a whole city block of houses up to another world, complete with intact buildings, forests, and all the people who live in that place. In this case the place is the deep ocean, and the buildings are holes and layers in the mud, the trees of the “forest” have trunks formed from chains of bacteria, the “grass” is a felt-like carpet of entwined strands of bacteria, and the residents themselves are tiny animals making their living in this place at the bottom of the ocean where a human, or even most fish and other familiar ocean creatures, could not possibly survive for a second.

This is a place akin to the fantasy world in the book “James and the Giant Peach,” where worms in the garden attain tremendous size due to a pesticide application error, and scale is warped from what we are used to. In our undersea world, the bacteria that are examined by Dr. Rouse and others under the microscope are growing even larger than the animals that graze among them. This is a world with very little oxygen, the life-giving element so ubiquitous in most of the rest of the world, and thus is different than nearly anything found on land. There are only five animals known to inhabit this hostile world, and one of the main purposes of this voyage is to discover what these animals are eating, and how they live in this world of bacteria, which is layered not only the environment but also the skins of many of the animal residents as well, like a thick winter coat, giving them a whitish appearance. Four of these animals are worms, and one is a snail, looking similar to something you might find in a garden, but smaller and more fragile in this still world without gravity, and sporting a coat of red bacterial paint. These incredibly tough gastropods can come up from 1500 feet, where the pressure on their bodies is about 40 times the air pressure of the surface, and still crawl around on the surface. They will be preserved by Dr. Rouse, brought back to the lab for genetic analysis by the chief scientist Mindi Summers, who will hopefully add to our knowledge of how these ecosystems function without either oxygen or light.

There are worlds within our planet that few or us are even aware of, but they are actually here, just a few miles west of the human chaos of the Los Angeles airport. There are deep-ocean animals living here in their own ways, just as they have been for million of years, free of the oxygen that we all require for our survival, interacting in complex and unknown ways, and attaining beautiful and creative life forms that we are only just now learning about. These animals might look like alien life forms, but they are not – they are residents on this planet just as we are, and in fact have generally been down here longer than we humans have been walking the earth. On this oceanographic research voyage we have reached down and touched a tiny corner of their world, and with Dr. Rouse as our translator and ambassador, we have stepped briefly into the living rooms of these tiny animals, and witnessed a small part of their lives . . .

Thanks to Dr. Greg Rouse, Professor and Curator of the Benthic Invertebrates Collection, Scripps Institution of Oceanography

Multi-species bacterial assemblage covering the floor of the ocean at 500 m (~1500 ft) deep

Masonerilla bactericola, a bacteria consuming annelid worm living in the bacterial mat.

Close-up of bacterial assemblage. The white spots are sulfer grains left from the utilization of hydrogen sulfide, the food of the bacteria.

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8 Responses to Descent to the bottom of the sea – B. Neal

  1. Michaela Charlton (Midpark High School) says:

    O my gosh that is so cool! So you found out all about this little “world” all by collecting mud? Wow! you learn something new everyday. The pictures are a really good quality. What kind of camera were those taken with? Keep up the great work! I’m looking forward to hear more about these little “worlds” and how they exist.

    • Ben Neal says:

      Yes, the whole record comes from a core of mud taken by a coring machine. In terms of the animals, the really interesting parts are all in the top 30cm layer. The bacterial mat is then removed carefully, and the material examined under a microscope to find the animals living there.

      The pictures were taken by Dr. Rouse with a pair of Canon EOS SLR cameras, hooked up to video monitors, and shooting through a pair of microscopes, one covering up to about 8x magnification, and the other one much more powerful. One of the key things for good microscopy is good light, and these are paired with two wirelessly-synched Canon strobes, fired with a handheld shutter release so that hand movement does not blur the image. This is a good setup, but microphotography can also be done just through the microscope itself with a hand held camera. Give it a try! It reveals details that you might not have noticed just looking through the microscope and can be really interesting. I was up all night last night taking pictures of very small larval fish, nearly transparent little things, taken in the net. Very good way to spend a night!

  2. Amber Martin says:

    WOW those pictures are amazing! That looks so interesting, and to think its like another world no one knows about. 🙂 So here is my question for today: How can you collect genetic information from life forms so microscopic? How ever it may be, does it take a long process? Well may you all be safe, and have fun. Bye

    • Ben Neal says:

      Genetic material can be collected from organisms this small and even smaller. There is one researcher on board, who is a medical doctor and genetics researcher, who has isolated fragments of DNA from a single spoonful of beach sand revealing over 10 million different species. Most of this is bacterial DNA, but he also sees markers for whales and fish and even cows in sea water. It does not take much extracted DNA to make a useful observation, thanks to a process called PCR (polymerase chain reaction) which multiplies the DNA many thousand times. The world is somewhat covered in free DNA in fact, and sometimes getting an amplification of just the DNA you want can be a problem.

      This is not a long laboratory process, and had had remarkable recent advances in the methods. You could try DNA extraction and amplification as a part of a science fair project, perhaps, and I would encourage you to further investigate this important field – it is a valuable skill that could use in college, grad school and in employment. This use of genetic signatures to determine the “tree of life” (i.e. the organization and relationships of the various species on earth) is called phylogenetics, and Dr. Rouse is an expert in this. Please see more information and more good pictures at http://spineless.ucsd.edu/Index.html

      Thanks for your questions! Ben Neal

  3. Taylor Hunt says:

    I think those pictures of the live squid are very interesting.

    • Ben Neal says:

      Squid are amazing creatures, and are so much more interesting when alive. Their skin coloration comes from chromatophores (pigment areas) that are controlled by muscles in the skin, which allows them to change their patterns so easily and quickly. This color is very apparent when they are fresh, and is very beautiful. We have had squid on every tow of the midwater net, and we have some good pictures of them.

  4. Ryan Juda says:

    Is there anything in particular your hoping to find in the mud block you brought up?

    • calechoes says:

      The main purpose of the mud blocks from the box corer was to obtain a biological representation of the surface layer. Other, deeper coring machines were used to get the deep, layered sediment records which are used for determining the history of the sediment. The box core brings up the largest surface area of the sea/sediment interface (more simply called the ocean floor!) and thus the largest amount of worms, snails and bacterial mat. This is then divided up and examined in little pieces under the microscope, and the little animals removed for counting, photography, and genetic analysis. In one of the box core samples we even caught an (unlucky) fish!

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