Archaea, one of three separate domains of life on our planet, were undiscovered until 1970. Since then, they had been found mostly in extreme environments such as high-temperature volcanic vents on the ocean floor, continental hot springs and fumeroles, and highly salty or acidic waters. Now, scientists funded by the National Science Foundation (NSF) have found unexpected, astounding numbers of archaea living in Earth's largest biome, the open sea.
The researchers--David Karl and Markus Karner of the University of Hawaii, and Edward DeLong of the Monterey Bay Aquarium Research Institute--have published a paper in this week's issue of the journal Nature on their discovery: "Archaeal dominance in the mesopelagic zone of the Pacific Ocean." The concentration of archaea in their study leads the scientists to conclude that archaea are "a large percentage of the biomass of the open ocean," says Karl. "These organisms could make up 50 percent of life in the open sea." The research is the first to note their numerical abundance.
"This remarkable new insight will have a major impact on our view of how the oceans function ecologically, "says Phil Taylor, director of NSF's biological oceanography program, which, along with NSF's chemical oceanography program, funded the research. "We are compelled by this discovery to increase our efforts to understand the diversity of life in the oceans, and the specific roles that important species and groups play in the sea."
The research is part of the Hawaii Ocean Time-series (HOT) project, an NSF-sponsored study of the north Pacific Ocean. Monthly sampling was conducted throughout the water column, from the surface to 4,750 meters deep. Two specific archaeal groups-pelagic euryarchaeota and pelagic crenarchaeota--were found in high numbers in the samples.