Unlocking Seafloor Systems: The Key to Understanding Life in Extreme Environments

With the advent of new technologies over the past 50 years, scientists have only just begun to explore and unravel the mysteries of Earth’s oceans. One of the greatest oceanic findings in recent history was the discovery of hydrothermal vents extending up from the seafloor among masses of new and exciting deep sea organisms. This discovery opened the doors for research on seafloor systems that could help us explain how life was managing to survive in such an extreme environment – an environment miles beneath the ocean surface, removed from the reach of sunlight. Over the past few years, scientists have been analyzing these hydrothermal structures to better understand how they are influencing and potentially regulating the supply of nutrients to these organisms. However, before diving into this study, it’s important to realize the basics of how the seafloor works.

The original and still operational deep submersible vehicle (DSV), the DSV Alvin, first located hydrothermal vents on the seafloor near the Galapagos Islands in 1977. Since then Alvin and many other DSVs have made trips to the seafloor studying these fascinating structures and the organisms they support.

If you were to drain the Earth’s oceans, you would see that running down the center of each ocean basin is a narrow valley lined with extensive mountain belts. This valley, which divides the seafloor into two equal sides, is where molten material from deep within Earth’s interior is brought to the seafloor where it cools to form new crust. This process, termed seafloor spreading, produces new crust which is gradually pushed outwards from the valley where it builds up to construct these mid-ocean mountain ridges. Zooming into this valley region where hot magma is rising to the seafloor, we can see that seafloor spreading is a complex process in which heat and fluid play an important role.

Seafloor spreading occurs along mid-ocean ridges, where scientists discovered the existence of hydrothermal vents. Vents emit plumes of chemical-rich fluids, as shown in black towards the center of this illustration.

The mixing of heated material with cold seawater, both at and within the seafloor, results in the formation of hydrothermal vents. These structures are mineral deposits of varying shapes and sizes that frequently develop in clusters around regions where seafloor spreading occurs. They contain networks of flow pathways capable of distributing mixed, nutrient-rich fluids to the oceans at varying speeds and temperatures where they can be used by organisms. Currently, my research has focused on characterizing the flow properties of vents, so that we can know more precisely how the interplay between the fluids and vents themselves influences the overall distribution of fluids. We have found that fluid interactions within vents exert a strong control on where and how long the vents will be able to transfer fluids. Of these fluid interactions, those that result in the blockage of vent flow pathways play a large role in the restriction of fluid flow from certain areas within the vents. Our data has also shown that vents frequently have specific sides or directions which are better able to transmit fluids.

Hydrothermal vents emit fluids commonly in smoke-like plumes. A variety of seafloor organisms live on and around the vents, taking in the released chemical nutrients.

Because hydrothermal vents play a critical role in maintaining environmental conditions along seafloor mid-ocean ridges, it is necessary for us to gain a greater understanding of how they work. Research has been done to characterize many of the fluids coming from vents, but far less work has been done on the actual vent structures. Our research was therefore motivated by the need for a better understanding of how vents evolve as a result of fluid flow within them. Our results can be used in combination with studies of vent fluids to predict how these seafloor settings and the organisms that live there will change over time.

Images are taken respectively from the following websites:
-http://blogs.ngm.com/blog_central/2009/07/overhauling-alvin.html
-http://www.marshallsystem.com/complete.htm
-http://www.noc.soton.ac.uk/chess/science/equatorial_belt.html