Okeanos Explorer (EX1304L1): Northeast U.S. Canyons Exploration

Vessel: NOAA Ship Okeanos Explorer; Expedition Dates: July 8 - 25, 2013

Project Principals: Kelley Elliott, NOAA/OAR/OER (Expedition Coordinator); Elizabeth Lobecker, NOAA/OAR/OER (Mapping Lead)

The purpose of Leg 1 of EX1304: Northeast U.S. Canyons Expedition is to employ the new 6,000 meter ROV, Deep Discoverer, and the camera towsled Seirios to explore targeted areas in the Northeast U.S. deepwater canyons. This mission complements the work done through the 2012 Atlantic Canyons Undersea Mapping Expeditions (ACUMEN).

USGS Hazard 3

Area

USGS Hazard 3; Northeast U.S. Canyons

Overview

Purpose

The purpose of this proposed dive is to investigate headwall scarps of a large landslide scar on the lower continental slope. The scientific rationale for this site is: To determine if these scarps are relatively young and if they pose a hazard in terms of tsunami generation. To evaluate the long term stability of landslide scars and test hypotheses about their evolution. To attempt to develop a means of using biologic activity on the scarps and deposits as a means of determining relative ages of the features and the response of bottom communities to catastrophic events.

USGS Hazard 4

Area

USGS Hazard 4; Northeast U.S. Canyons

Overview

Purpose

The purpose of this proposed dive is to investigate pockmarks on the upper continental slope between 500 and 650 m water depth directly above the headwall scarp of a landslide. The scientific rationale for this site is to: To investigate the potential for these feature to be created by ephemeral or long-lived fluid flow (gas, water, etc.). To characterize the pockmark morphology, sediment infilling, and linkages to nearby landslides. To evaluate the long term stability of landslide scars and test hypotheses about their evolution. To attempt to develop a means of using biologic activity on the scarps and deposits as a means of determining relative ages of the features and the response of bottom communities to catastrophic events.

New England Seep 3

Area

New England Seep 3; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to investigate 4 potential seep sites that were identified based on bubbles plumes seen during 2012 multibeam mapping on the Okeanos explorer. The primary purpose of the dive was to determine if there are methane seeps within the region and to describe both their geology (vigor and extent of seepage, distribution of authigenic carbonates, relationship of seeps to seafloor geology) and their ecology (community structure, distribution of live and dead animals, similarity to faunal assemblages at Veatch seep).

New England Seep 2

Area

New England Seep 2; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to investigate 4 potential seep sites that were identified based on bubble plumes seen during recent multibeam mapping by the Okeanos Explorer including 3 targets that were identified the night before. The primary purpose of the dive was to determine if there are methane seeps within the region and to describe both their geology (vigor and extent of seepage, distribution of authigenic carbonates, relationship of seeps to seafloor geology and their ecology (community structure, distribution of live and dead animals).

Hydrographer Canyon Mid 1

Area

Hydrographer Canyon Mid 1; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to explore for deep-sea corals (DSC), DSC associates, and other deep-water benthic and mobile fauna such as sponges, fishes and crabs. This was considered a mid-depth dive (~1500-900 m). An additional goal of this dive was to groundtruth a model that predicted the occurrence of DSC associated with slopes >36 degrees.

Hydrographer Canyon Shallow 2

Area

Hydrographer Canyon Shallow 2; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to explore for deep-sea corals (DSC), DSC associates, and other deep-water benthic and mobile fauna such as sponges, fishes and crabs. This was considered a shallow-depth dive (~900-600 m). An additional goal of this dive was to groundtruth a model that predicted the occurrence of DSC associated with slopes >36 degrees.

Atlantis Canyon Mid 1

Area

Atlantis Canyon Mid 1; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to characterize submarine canyon geomorphology and characterize benthic habitats in Atlantis Canyon, possibly including deep-sea coral and sponges. This was considered a mid-depth dive (~1100-900 m). An additional goal of this dive was to groundtruth a model that predicted the occurrence of deep-sea corals associated with slopes >36 degrees.

Atlantis Deep

Area

Atlantis Deep; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities at a depth of ~1800 m on the east wall of Atlantis. Groundtruth a model of predicted deep-sea coral occurrence.

Alvin Canyon Shallow 1

Area

Alvin Canyon Shallow 1; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities at a depth of ~900 m on the west wall of Alvin Canyon. Groundtruth a model of predicted deep-sea coral occurrence.

Alvin Canyon Mid 2

Area

Alvin Canyon Mid 2; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities at a depth of ~1100 m on the east wall of Alvin Canyon. Groundtruth a model of predicted deep-sea coral occurrence.

Block Canyon Mid 2

Area

Block Canyon Mid 2; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities at a depth of ~1300 m on the east wall of Alvin Canyon. Groundtruth a model of predicted deep-sea coral occurrence.

USGS Hazard 3

Area

USGS Hazard 3; Northeast U.S. Canyons

Overview

Purpose

The purpose of this proposed dive is to investigate the transition (marked by the red dashed line on the map) from canyon processes to landslide deposition within Veatch Canyon to establish relative timing of the landslide event. The Veatch Canyon landslide breaches the eastern levee of Veatch Canyon and deposits debris within the canyon, blocking the normal sediment transport pathway. If Veatch Canyon is still active, the landslide may be relatively young (Recent), but if Veatch Canyon has been inactive since the LGM, the landslide may be late Pleistocene in age.

New England Seep 1

Area

New England Seep 1; Northeast U.S. Canyons

Overview

Purpose

An engineering dive discovered live mussel beds (some with juveniles), extensive dead mussel debris (with methane bubbling), bacterial mats, carbonates, and other indicators of chemosynthetic activity. Our 21 Jul 2013 dive purpose was to resurvey this area, particularly the southern portion that was only documented for moments before recovery of the ROV during the engineering dive. Dive objectives included imaging with lasers, to get estimates of the sizes of the mussels, associated fauna, and rate of bubble ascent from seafloor for at least 1 min. Another objective included groundtruthing a new water column anomaly that was detected by multibeam sonar on the 20th of July.

Block Canyon Deep

Area

Block Canyon Deep; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to explore a deep portion of Block Canyon and describe the geomorphology and biological communities along the east wall at a depth of ~2000 m.

Block Canyon Deep

Area

Block Canyon Deep; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: Explore a shallow area of Block Canyon and describe the geomorphology and biological communities along the east wall at a depth of ~1100-1000 m. Groundtruth a model that predicted coral occurrence based on slopes of >36 degrees.

Block Canyon Deep

Area

Block Canyon Deep; Northeast U.S. Canyons

Overview

Purpose

The purpose of this dive was to describe the geomorphology and benthic communities of both east and west walls in a minor canyon, site named Gauntlet Minor, to a depth of ~1100-1000 m.