Windows to the Deep 2019 - Exploring Deep Sea Habitats of the Southeastern U.S.

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Although the East Coast is home to millions of Americans and is experiencing some of the highest population growth rates in the United States, the southeast U.S. continental margin has some of the largest gaps in high-resolution ocean mapping data on the East Coast and limited previous observations via submersibles. In fact, the deep-water areas offshore Florida, Georgia, South Carolina, and North Carolina are some of the least explored areas along the U.S. East Coast.

From May 30 through July 12, 2019, USGS joined NOAA and partners on NOAA Ship Okeanos Explorer to collect critical baseline information about unknown and poorly understood deep-water areas of the southeastern United States. The research expedition is part of the multiyear, multiagency ocean exploration effort known as “Windows to the Deep.” 

In 2019, the 38-day, two-leg expedition focused on priority exploration areas identified by the ocean management and scientific communities. And on the 100th mission for the Okeanos Explorer, it visited new methane plumes where the U.S. Atlantic seeps story began. In November 2012, through a collaboration between NOAA’s Office of Ocean Exploration (OER) and the USGS, the Okeanos Explorer mapping team discovered the first evidence of widespread seafloor methane seepage on the northern U.S. Atlantic margin. This initial discovery led to the subsequent identification of over 570 seafloor methane seep sites using 94,000 square kilometers (58,409 square miles) of sonar data collected between Cape Hatteras and Cape Cod.

Excerpt from the Ship’s Mission Log July 12, 2019:

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By Adam Skarke (Department of Geosciences, Mississippi State University), Carolyn Ruppel (USGS), and Shannon Hoy (Cherokee Nation Strategic Programs at NOAA Office of Ocean Exploration and Research)

Since the initial discovery in 2012, USGS, NOAA, BOEM, the National Science Foundation, the U.S. Department of Energy, and private foundations have sponsored exploration of the seafloor and water column in the Norfolk Seeps area and other Atlantic margin seeps sites. These studies have used ROVs, Deep Submergence Vehicle (DSV) Alvin, and autonomous vehicles and have involved the deployment of numerous imaging and sampling technologies to investigate the unique ecology, geochemistry, oceanography, and geophysics in seep environments and to study methane and gas hydrate dynamics.

Final mission Dive 19 proceeded from a depth of about 1,625 meters (1 mile) upslope to about 1,530 meters (0.95 miles) through a cluster of methane plumes mapped on the south side of a pronounced ridge. The area has effusive gas discharge, robust chemosynthetic ecosystems, extensive beds of Bathymodiolus childressi mussels, abundant carbonate rock, and ubiquitous bacterial mats. In addition, a second, much larger type of mussel (Bathymodiolus heckerae) has been collected at the seeps, the first such occurrence of this species so far north on the U.S. Atlantic margin.

As the dive continued, the team observed an increasing density of empty Bathymodiolus mussel shells, and the scene then transitioned to beds of live Bathymodiolus childressi mussels adjacent to outcrops of authigenic carbonate rocks. Dense bacterial mats and distributed echinoderms and anemones were also seen, as well as rays, fish, and crabs.

Read the full mission log.

At this NOAA site, you can find daily expedition updates, meet the scientists, read the mission logs, check out the image and media gallery, get information for educators, media, and more background materials.