Mapping the Seafloor

A stunning array of corals and sponges adorned most areas explored during dive 9 of the Deep Connections 2019 expedition on Retriever Seamount. The high diversity and density seen here was characteristic of the entire dive.

Waveglider used to communicate with a geodesy station's seafloor transponders.

A hydrothermal vent, where seawater that has seeped into undersea rocks is heated by exposure to magma, then rises and vents into the ocean.

A carbonate reef, made up of various pieces of carbonate rock covered in sediment. The carbonate likely formed when methane-eating bacteria in the sediments caused the environment to become alkaline, resulting in carbonate precipitating out to form the rocks.

Capturing methane bubbles at depth with special tools on ROV SuBastian.

Human occupied vehicle, Alvin, descends to the seafloor.

This bright yellow glass sponge (Hertwigia sp.) is one of many different sponge species found in the southeastern US. They are so named for the glass-like silicon spicules that support their skeletons.

Mineral-laden water emerging from a hydrothermal vent on the Niua underwater volcano in the Lau Basin, southwest Pacific Ocean. As the water cools, minerals precipitate to form tower-like “chimneys.” Image taken during 2016 cruise “Virtual Vents.”  

Corals and sponges near La Cruz Canyon, offshore of south-central California.

A team of USGS scientists work off the R/V Sallenger in Rockaway Beach, New York. One team member stands on a floating sled that enables sub‐bottom surveying in shallow water, nearshore, and shore‐face environments. The sled is equipped with an EdgeTech SB‐512i CHIRP system and single‐beam sonar.

Oceanographic instrumentation is ready for deployment off of Fire Island to measure how the offshore bathymetry (shown in background map) influences coastal response. 

Healthy elkhorn coral (Acropora palmata) on the seafloor along the southeastern coast of Buck Island, U.S. Virgin Islands. Elkhorn coral is one of many important reef-building species that create 3D structure on the seafloor. Coral reef structure provides habitat for marine life and helps break up waves as they approach the coastline.

Methane-derived authigenic carbonate (MDAC) rocks on the seafloor on the U.S. Atlantic margin

Graphic showing geophysical and sampling systems used to define the seafloor topography, surface sediments, and underlying geology.

Seafloor geology map from a 2017 journal article by Johnson and others, published in Coastal and Ocean Management. Shaded digital elevation model (DEM) showing submarine landslides and sites of potential f

Time series of the coral reef at Grecian Rocks (Key Largo, FL) illustrating an example of the dramatic decline in live coral on Florida Keys reefs in recent decades. From Shinn and Kuffner (2017).

SeaBOSS on the fantail of the R/V Connecticut on Long Island Sound at sunrise

The ship’s crane operator slowly moves the Sentry over the side and back onto the deck.

Page Valentine works with NOAA staff from the Stellwagen Bank National Marine Sanctuary to ready the SEABoss for deployment off the fantail of the NOAA R/V Auk. 

Page Valentine and Dann Blackwood on the fantail of the NOAA R/V Auk.  Dann is photographing a sediment sample collected on the seabed.