Assistant Professor Melissa Anderson and ES graduate student Jonathan Umbsaar took part in the RV Falkor (too) expedition to the Mid-Atlantic Ridge in search of “Hydrothermal Lost Cities”. The main goals of the expedition were to seek examples of Lost City-type hydrothermal fields and to find clues regarding processes required to spark life on Earth.
The Lost City hydrothermal field was discovered in 2000 and was unlike any other at the time. The conventional submarine hydrothermal system forms when seawater interacts with basalt rocks near the magma chambers of deep-sea volcanoes. However, in the Lost City, the seawater interacts directly with mantle rocks through a chemical process called serpentinization. These types of vents are harder to detect because they are lower in temperature and don’t release minerals into the water column, but, ironically, these systems might still be common on the ocean floor.
More interesting is the fact that rather than being desolate, the vents in Lost City are teeming with life. Here, organisms can adapt and thrive using the organic compounds formed from the serpentinization process. This unique process of forming organic compounds might be key to understanding how life began on Earth.
The Lost City hydrothermal field also forms vents made of almost pure carbonate – the same material that makes up limestone cave formations. Carbonate minerals remove carbon dioxide from seawater and therefore, over time scales of hundreds to hundreds of thousands of years, these types of hydrothermal fields might have played a vital role in regulating the amount of carbon dioxide in the oceans.
Understanding the Lost City hydrothermal field will allow earth scientists to (1) evaluate whether this type of hydrothermal system is unique or not and (2) provide insights on the recipe that led to life on Earth. Discovering more hydrothermal systems like the Lost City will help scientists to navigate through outstanding questions in Earth Sciences!