Mid and Southeast US (ROV & Mapping)

Vessel: NOAA Ship Okeanos Explorer; Expedition Dates: June 20, 2019 to July 12, 2019

Ports: Port Canaveral, FL to Norfolk,VA

Project Principals: Kasey Cantwell, NOAA/OAR/OER (Expedition Coordinator); Shannon Hoy, NOAA/OAR/OER (Mapping Lead)

The deepwater areas offshore Florida, Georgia, South Carolina, and North Carolina are some of the least explored areas along the U.S. East Coast. In 2019, NOAA and partners conducted a two-part expedition to map and characterize this area to support priorities put forward by the deep-ocean science and resource management communities. The primary objective of the expedition was to survey deepwater areas offshore of Florida, Georgia, South Carolina and North Carolina in order to provide baseline information to support management and science needs. This two-part expedition used the ship's deepwater mapping systems (Kongsberg EM302 multibeam sonar, Simrad EK60 and EK80 split-beam fisheries sonars, Knudsen 3260 chirp sub-bottom profiler sonar, and Teledyne Acoustic Doppler Current Profiler [ADCP]), NOAA's two-body deepwater remotely operated vehicle (ROV), and a high-bandwidth satellite connection for real-time ship to shore communications. This cruise report details activities associated with the second leg of the Windows to the Deep 2019 expedition (EX1903L2). 19 ROV dives were conducted, ranging in depth from 298 to 3,490 meters (978-11,450 feet) to improve knowledge of unexplored areas within the U.S. Exclusive Economic Zone (EEZ) to inform management needs for sensitive habitats, maritime heritage sites, and potential resources. EX1903L2 also mapped 14,314 square kilometers of seafloor to extend bathymetric mapping coverage in the U.S.EEZ in support of Seabed 2030 and NOAA's goal to map and characterize the U.S. EEZ. Data from this expedition will help to improve our understanding of the deep-ocean habitats of the U.S. continental margin and of the connections between communities throughout the Atlantic Basin

Canaveral Deep

Area

Canaveral Deep; Test Area

Overview

Purpose

A primary purpose of this dive is to explore the southern extent of the "Million Mounds" region of the Stetson Miami Terrace Deepwater Coral HAPC and investigate the possible influence of the Gulf Stream on deepwater habitats. The dive will target one of the east-west lateral trending mounds that are common throughout the area and could potentially be biogenic habitat for corals and associated fauna.

Stetson Mesa South Mounds

Area

Stetson Mesa South Mounds; Southeast US Continental Margin

Overview

Purpose

The three primary purposes of this dive were to: 1) explore underwater mounds in Million Mounds region that has high potential to be suitable habitat for deep sea coral and sponge communities, 2) investigate area with unusual backscatter data for ground-truthing, and 3) perform mid-water transects on the ascent to characterize and sample water column biota.

Stetson Mesa South Scarp

Area

Stetson Mesa South Scarp; Southeast US Continental Margin

Overview

Purpose

This dive will explore the Stetson Mesa South Scarp, part of the Blake Plateau. This area is part of the Stetson Miami Terrace Habitat Area of Particular Concern (HAPC) and was mapped on the first leg of the Windows to the Deep 2019 Expedition. The area has the potential to be a suitable habitat for deep sea corals and sponges. This area is a high priority region for the Southeast Deep-Sea Coral Initiative (SEDCI) from the NOAA Deep-Sea Coral Research and Technology Program.

Blake Plateau Knolls

Area

Blake Plateau Knolls; Southeast US Continental Margin

Overview

Purpose

This dive was conducted at a knoll feature on the Blake Plateau. This region of the Blake Plateau was first identified and mapped on the EX1806 Windows to the Deep 2018 Expedition. They planned on doing an EX1903 ROV dive on one of these knolls but were operationally unable, so this dive became a priority for this expedition. The mapping conducted on EX1806 revealed multiple knolls that were isolated from each other by a few hundred meters. Based on the bathymetry there was likelihood this feature could be a cold-water coral mound and was worth investigating further through an ROV dive.

Central Plateau Mounds

Area

Central Plateau Mounds; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive is to explore and characterize the habitat of deep-water coral and sponges that inhabit a grouping of knolls on the Central Blake Plateau. The Blake Plateau, long described as a relatively flat, current-swept plain between the continental shelf and deep-ocean basin of the North Atlantic, is a relatively unexplored part of the Southeast Atlantic coast and, therefore, the biota of this area is mainly undescribed. Mapping of the central region of the Blake Plateau completed on Leg 1 of the Windows to the Deep 2019 expedition revealed many small mounds and knolls that have the potential to be suitable habitat for deep-sea corals and sponges. Commercial fishermen have begun targeting this area for fish species that may grow large, but very slowly, so studies of the benthic communities is important to characterize habitat suitability models. This dive will provide valuable information to start to fill-in this large data gap.

Stetson Mesa Potential Seep

Area

Stetson Mesa Potential Seep; Southeast US Continental Margin

Overview

Purpose

Bathymetric data was collected around this region of the Blake Plateau by the Okeanos Explorer during 2014. Adam Skarke's Lab at Mississippi State University was able to analyze the EM302 water column data and assign a relatively high confidence (2 out of 5) that a cold seep could be in the area. There were two potential seep sites identified and the more northern site, with more topographic variability, was selected to increase the likelihood of encountering benthic communities that have settled on or around the authigenic carbonate. This dive will give us the opportunity to investigate a potential cold seep, which are known to provide resources and habitat for a wide variety of life forms and significantly impact ocean chemistry in the surrounding water. On the ROV ascent, we will be doing several mid-water transects (700 m, 500 m, and 300 m) to observe and collect the biota in the vastly unexplored water column.

"Shark Rock"

Area

"Shark Rock"; Southeast US Continental Margin

Overview

Purpose

Locate and identify a potential shipwreck target. Once confirmed that this site was not an Underwater Cultural Heritage site, UCH protocols were secured and the dive preceded with benthic characterization.

Central Plateau Scarp

Area

Central Plateau Scarp; Southeast US Continental Margin

Overview

Purpose

During the mapping portion of the EX1903 Windows to the Deep 2019 expedition, an interesting temperature profile was noted on several XBT casts near a scarp within the central Blake Plateau. Following a subsequent CTD cast, it was determined that there was a sharp drop in temperature, decrease in salinity and increase in dissolved oxygen at approximately 860 meters water depth. The dive track was planned to transit through this depth layer, up the face of the scarp and then along the top of the plateau. CTD data on the ROV will be collected throughout the entire dive. The first objective of this dive is to confirm the temperature, salinity, and dissolved oxygen anomaly at a depth of approximately 860 m in the central Blake Plateau. Upon reaching the bottom, the seafloor habitat and geology will be characterized as we travel up along the face of a 120 m scarp.

Blake Escarpment Mid

Area

Blake Escarpment Mid; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive is to explore and characterize the habitat of deep-water coral, sponges, and associated fauna that inhabit an escarpment on the Blake Plateau. Also, gather data and samples from the midwater above the dive target. This dive will provide a survey of a deeper escarpment (1,400-1,300 meters) than the previous scarps during this expeditions. We will then perform midwater transects above the dive site to gain insight into the communities of this vast and understudied pelagic habitat.

Richardson "Jellyfish"

Area

Richardson "Jellyfish"; Southeast US Continental Margin

Overview

Purpose

This site is to the south of the region explored on the Windows to the Deep 2018 expedition when a large deep sea reef was discovered. Leg 1 of the Windows to the Deep 2019 mapped more of the area and found this feature that appears to be an underwater slump and has the same characteristic mounds around the top of the feature as those seen in Richardson Reef. This dive will help to identify any further extent of the reef complex.

Deep "Dodge" Canyon

Area

Deep "Dodge" Canyon; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive is to explore and characterize a small canyon that has the potential to be suitable habitat for deep-water coral, sponges, and associated fauna.

Deep Pamlico Canyon

Area

Deep Pamlico Canyon; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive is to explore and characterize a small canyon that has the potential to be suitable habitat for deep-water coral, sponges, and associated fauna.

"Roanoke Minor" Canyon (unnamed minor canyon offshore of Roanoke VA)

Area

"Roanoke Minor" Canyon (unnamed minor canyon offshore of Roanoke VA); Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive was to explore and characterize a small canyon that has the potential to be suitable habitat for deep-water coral, sponges, and associated fauna.

Bodie Island Seep

Area

Bodie Island Seep; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive was to explore and characterize a small canyon that has the potential to be suitable habitat for deep-water coral, sponges, and associated fauna.

Currituck Base

Area

Currituck Base; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive is to explore and characterize an area with relatively steep slope on the Currituck landslide off the North Carolina coast.

Washington Canyon

Area

Washington Canyon; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive was to explore and characterize a section of wall within Washington Canyon, one of the mid-Atlantic canyons, with a relatively steep slope that has the potential to be suitable habitat for deep-water coral, sponges, and associated fauna.

Wilmington Canyon

Area

Wilmington Canyon; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive is to explore and characterize a mid-Atlantic canyon wall with a relatively steep slope that has the potential to be suitable habitat for deep-water coral, sponges, and associated fauna.

Baltimore Canyon

Area

Baltimore Canyon; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive is to explore and characterize a mid-Atlantic canyon wall with a relatively steep slope that has the potential to be suitable habitat for deep-water coral, sponges, and associated fauna.

Norfolk Deep Seep

Area

Norfolk Deep Seep; Southeast US Continental Margin

Overview

Purpose

The primary objective of this dive is to explore and characterize ecological conditions and geological features at a dense area of effusive gas seeps. These seeps have not been previously characterized and will serve as a point of ecological and geological comparison with seeps to the immediate northwest and northeast.