Okeanos Explorer (EX1304L2): Northeast U.S. Canyons Exploration

Vessel: NOAA Ship Okeanos Explorer; Expedition Dates: July 31 - August 17, 2013

Project Principals: Brian Kennedy, NOAA/OAR/OER (Expedition Coordinator); Adam Skarke, NOAA/OAR/OER (Mapping Lead)

From July 31 to August 16, the Northeast U.S. Canyons 2013 Expedition continued exploration of the geomorphology and benthic ecology of deep-sea canyons and Mytilus Seamount along the Northeast US Atlantic margin. During Leg 2 of this mission, ROV Deep Discoverer (D2) surveyed the area extending between Alvin and Block canyons in the west and Heezen Canyon (eastern limit of the EEZ) to the east. Fifteen dives, ranging in depth from 490 to 3300 m were completed at five named canyons (Nygren, Heezen, Oceanographer, Lydonia, and Welker), one minor canyon (unnamed near Shallop Canyon), two intercanyon sites, two USGS geohazards targets, and Mytilus Seamount.

USGS Hazard 1

Area

USGS Hazard 1; Northeast U.S. Canyons

Overview

Purpose

The purpose of this proposed dive is to investigate small, potentially recent, landslide debris deposits and scarps within a larger landslide scar on the upper continental slope. The scientific rationale for this site is: 1. To determine if these small landslide debris features are relatively young and if they pose a hazard in terms of tsunami generation. 2. To evaluate the long term stability of landslide scars and test hypotheses about their evolution. 3. 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.

Minor Canyon near Shallop Canyon

Area

Minor Canyon near Shallop Canyon; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities in a minor canyon near Shallop Canyon. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Oceanographer Canyon 1

Area

Oceanographer Canyon 1; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities at a depth of ~1200 m in Oceanographer Canyon. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Mytilus Seamount North

Area

Mytilus Seamount North; Northeast U.S. Canyons

Overview

Purpose

Despite a significant level of past effort, the New England seamounts, a major chain of undersea mountains, remains largely unexplored. Building on previous work, we will conduct the first ecological explorations of the New England seamounts. Of those seamounts within the US EEZ, Mytilus Seamount has yet to be visited in this regard. This dive will explore steep terrain along the north side of the seamount to characterize deep sea coral and sponge communities.

Mytilus Seamount South

Area

Mytilus Seamount South; Northeast U.S. Canyons

Overview

Purpose

Despite a significant level of past effort, the New England seamounts, a major chain of undersea mountains, remains largely unexplored. Building on previous work, we will conduct the first ecological explorations of the New England seamounts. Of those seamounts within the US EEZ, Mytilus Seamount has yet to be visited in this regard. This dive will explore steep terrain along the south side of the seamount to characterize deep sea coral and sponge communities.

Nygren Canyon Mid Deep

Area

Nygren Canyon Mid Deep; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities at a depth of ~1300-1600 m on the southwestern wall of Nygren Canyon. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Heezen Canyon Deep

Area

Heezen Canyon Deep; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities at a depth of ~1400-1700 m on the southwestern wall of Heezen Canyon. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Nygren Canyon Shallow

Area

Nygren Canyon Shallow; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities at a depth of ~900 m on the northeastern wall of Nygren Canyon. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Heezen Canyon Shallow

Area

Heezen Canyon Shallow; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities at a depth of ~1400-1700 m on the southwestern wall of Heezen Canyon. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Nygren/Heezen Intercanyon

Area

Nygren/Heezen Intercanyon; Northeast U.S. Canyons

Overview

Purpose

The New England and Mid-Atlantic Fisheries Management Councils are particularly interested in intercanyons to provide more information on depth boundaries for deep-sea coral protection. The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Lydonia/Powell Intercanyon

Area

Lydonia/Powell Intercanyon; Northeast U.S. Canyons

Overview

Purpose

The New England and Mid-Atlantic Fisheries Management Councils are particularly interested in intercanyons to provide more information on depth boundaries for deep-sea coral protection. The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Lydonia Canyon

Area

Lydonia Canyon; Northeast U.S. Canyons

Overview

Purpose

The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Oceanographer Canyon 2

Area

Oceanographer Canyon 2; Northeast U.S. Canyons

Overview

Purpose

This dive track is along the approximate location of Alvin dive 1035 from 1980 and 3702 from 2001 and will examine potential changes in the biology and geology of the area over 30+ years. The purpose of the dive was to: 1. Characterize the submarine canyon geomorphology and benthic habitats, including possible coral and sponge communities. 2. Groundtruth a model of predicted deep-sea coral occurrence.

Welker Canyon

Area

Welker Canyon; Northeast U.S. Canyons

Overview

Purpose

The dive track was chosen based on a combination of regional habitat prediction models for deep sea corals and local identification of high slope features from 20 m multibeam mosaics. Past experience and modeling in this region indicates that deep sea coral habitats are often found in the canyons in areas with slopes > 360.

USGS Hazard 3

Area

USGS Hazard 3; Northeast U.S. Canyons

Overview

Purpose

The purpose of this proposed dive is to investigate small, potentially recent, landslide debris deposits and scarps within a larger landslide scar on the upper continental slope. The scientific rationale for this site is to: 1. Determine if these small landslide debris features are relatively young and if they pose a hazard in terms of tsunami generation. 2. Evaluate the long term stability of landslide scars and test hypotheses about their evolution. 3. 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.