Finding a new, high-temperature, off-axis hydrothermal vent field on the floor of the Pacific Ocean at 2,550 meters depth could change scientists’ understanding of the impact that such ocean-floor vent systems have on the life and chemistry of Earth’s oceans.
A team of researchers including Jill McDermott, chemical oceanographer and faculty member in Lehigh's Department of Earth and Environmental Sciences, discovered the off-axis hydrothermal field, named YBW-Sentry, in the area of the global mid-ocean ridge known as the East Pacific Rise. The study area is about 200 miles off the coast of western Mexico. The new vent site covers an area equivalent to a football field, roughly twice the size of the nearest active hydrothermal vents in the region. The chimneys resemble candelabras that are the height of a three-story building. The findings have been published in an article entitled: “Discovery of Active Off-Axis Hydrothermal Vents at 9° 54’N East Pacific Rise,” in the Proceedings of the National Academy of Sciences (PNAS).
Deep-sea hydrothermal vents are found around the world, most often in volcanically active locations along the crest of the global mid-ocean ridge system. Magmatic activity, driven by upwellings of heat in Earth’s mantle, causes the brittle tectonic plates that make up Earth’s outer shell, or crust, to split. As the plates spread, new seafloor rock is formed by magmatic activity and volcanic eruptions. This magmatic and tectonic activity creates cracks through which sea water percolates in crustal rocks. Much like hot springs on land, hydrothermal vents spout mineral-rich liquid that has been heated beneath the seafloor.
The research that led to the discovery of the off-axis vent field along the East Pacific Rise was spearheaded by the McDermott lab at Lehigh. The team collects fluids from the black smoker chimneys and analyzes them for their geochemical characteristics, which can indicate the temperatures at which the fluids are forming. Hotter temperatures could be a sign of an impending eruption. At the same time, the team also instruments the active vent chimneys with self-recording fluid temperature loggers to provide measurements every ten minutes over 2-year time periods. The temperature measurements provide a time series of the changes the vents experience. The research team has nine vents instrumented in the study area.