Deep Ocean Biosphere

What’s Down Below?

I’m McKensie Daugherty, your host for On the Ocean. What could possibly live at the very bottom of the ocean? Microbes! That’s right, microbial organisms including bacteria, archaea and fungi live at the bottom of the ocean, and the bottom of the ocean is a fascinatingly diverse place. There are many features on the bottom of the ocean where you would think no life could exist, such as hydrothermal vents. These are fissures in the earth’s surface where incredibly hot fluids issue out into the deep ocean. These fluids can be as hot as 400 degrees Celsius, but do not actually boil because it is so deep in the ocean that the high pressure keeps the molecules in liquid form. These vents would seem to be one of the most inhospitable places in the world to find life, however scientists discovered several different types of life living right on the vent structures themselves! Most notably they found microbes that could not only stand the heat, but like to use the large amount of sulfide available to respire. These microbes represent just some of the life that can live in incredibly harsh environments found on the ocean seafloor! This month we will talk about the diversity of life found on the seafloor and how scientists research these microbes and their implications on the entire earth. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Contributing Professor: Dr. Jason Sylvan

 

Active hydrothermal vents from Mariner vent field, in the Eastern Lau Spreading Center

Credit:NSF Ridge2000

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Sediment Microbes

I’m McKensie Daugherty, your host for On the Ocean. Microbes can be found in the deepest parts of the ocean sea floor, into the many layers of the sediment. In fact, there as many microbial cells in the sediment layers of the ocean as in all the layers of the water combined! The layers of sediment and further down into earth’s crust are full of microbial life, and scientists have found microbial life as far as 1.5 miles below the seafloor. Here the bacteria live lots of different lifestyles, and grow slowly in the sediments around them. Oxygen depletes the further down in the sediment you go, so many of these organisms use other elements to respire. Manganese, nitrate, iron, and sulfate are a few chemicals that microbes can use to breathe other than oxygen in the deep ocean sediment. While breathing these chemicals, microbes eat carbon in the sediments. In fact, the ocean sediment is the final resting place for carbon in its nutrient cycle around the earth. Making it important to study sediment microbes to understand the role they play in the earth’s carbon cycle. In particular, it will be important to understand if they are impacted by rising levels of carbon in the air due to human activity, which eventually leads to more carbon in the oceans. Overall, microbes living in the sediment lead very interesting lifestyles and contribute to carbon usage in the sediment floor. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

 Contributing Professor: Dr. Jason Sylvan

Rock Microbes

I’m McKensie Daugherty, your host for on the ocean. Just as microbes live in the sediment layers of the ocean seafloor, they also inhabit the rock layer underneath the sediment. This layer of seafloor is created at mid-ocean ridges, and spreads out over the earth where it slowly gets covered with sediment over time. In this rock layer are cracks and holes, where water flows through, connecting water from all the oceans over long periods of time. Microbes are able to live in these pores and cracks of the rock layer and can use the iron and reduced sulfur inherent in the rocks to make the energy for metabolizing carbon without the presence of light. The microbes living there utilize the elements at their disposal in fascinating ways, and these interactions have key global consequences for the cycling of carbon all over the earth. For this reason, studying deep sea floor microbes has become a large initiative for scientists around the world. By understanding their role in global carbon cycles, researchers can learn the impacts these organisms have on a global scale. Considering that the rocks below the seafloor comprise the largest continuous microbial habitat on earth, this impact could be very important. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

Contributing Professor: Dr. Jason Sylvan

Deep Seafloor Science

I’m McKensie Daugherty, your host for On the Ocean. This month we have been discussing the ocean seafloor, and the amazing kinds of prokaryotes that live there. This week we dive in to how scientists study these microbes, and why they are important for global climate change. Once collected, bacterial cells found in the sediment or rock layers of the ocean floor are analyzed using techniques that look at bacterial DNA and RNA. These molecules can tell scientists what kind of organism they are, what they eat, and what they breathe. These are the kinds of questions that explain what impact these microbes have on their environment, and on global nutrient cycles. Where these microbes appear is also of great interest. Microbes that live on the hydrothermal vents can provide interesting details about the life of these vents. By looking at the identity profiles of the microbes found in active and inactive vents, scientists can compare the communities to better understand how microbial communities interact with the changing environment they live in. Understanding these bacteria and their roles in global cycling of nutrients like carbon, nitrogen, and phosphorus is an important part of oceanographic work at Texas A&M University. This has been On the Ocean, a program made possible by the Department of Oceanography and a production of KAMU-FM on the campus of Texas A&M University in College Station. For more information and links, please go to ocean.tamu.edu and click On the Ocean.

 

 Contributing Professor: Dr. Jason Sylvan