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Images: Fungi Flourish Below the Seafloor

WHOI postdoctoral fellow Bill Orsi led a team of researchers who identified more than 70 kinds of fungi living in ocean sediments as far as 48 meters (157 feet) below the seafloor. (Photo courtesy of Bill Orsi, Woods Hole Oceanographic Institution)

Bar graphs show that ocean sediments from five sites around the world are home to different kinds and numbers of fungi. Each bar represents a sample from one site.  The colored and numbered strips on the bars represent different species of fungus. The bigger the strip, the more of that kind of fungus was in the community. Nutrient-rich sediments near coastlines (first, third, and fifth bars) had relatively few fungal species. Nutrient-poor sediments in the deep ocean (second and fourth bars) had more diverse fungal communities. Numbers along the bottom show the depths of each sample, in meters below sea floor (mbsf). Numbers along the left side of the graph show the percentage of the total fungi. BSP=Banguela Upwelling System. EEP=Eastern Equatorial Pacific. HR=Hydrate Ridge. NP=North Pond near the Mid-Atlantic Ridge. PM=Peru Margin. (Courtesy of Bill Orsi, Woods Hole Oceanographic Institution)

Bill Orsi (left) and his postdoctoral mentor, WHOI microbiologist Virginia Edgcomb (right), look for and analyze microscopic organisms living in extreme habitats, such as deep sediments, hypersaline pools, and anoxic (oxygen-free) areas of the ocean. Here, they work on an instrument designed to sample, incubate, and preserve microbes from specific depths in the ocean. (Photo by Cherie Winner, Woods Hole Oceanographic Institution)

Orsi and his colleagues analyzed samples from sediment cores similar to this one. Cores are collected by driving long pipes deep into the sediments, then withdrawing them with sediment inside. Back in the lab, each pipe is split down the middle, giving researchers access to the interior of the core. The age of a particular sample is determined in part by measuring its distance from the top of the core (which was at the seafloor). Other methods used to date samples include radiocarbon dating and assessing the microfossils embedded in the sediments. (Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)