Okeanos Explorer (EX1404L3): ROV Exploration and Mapping Northeast Seamounts and Canyons

Vessel: NOAA Ship Okeanos Explorer; Expedition Dates: September 16 - October 7, 2014

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

During EX1404 Legs 2 and 3, our team conducted sixteen dives with ROV Deep Discoverer (D2) that explored six seamounts and nine canyons, of which four seamounts and five canyons had never been explored before. We investigated several different habitats at depths ranging from 660 meters to 4692 meters and documented deep-sea corals and their associated invertebrates, a variety of fish and other benthic animals, a diversity of mid-water fauna, and a number of species we have yet to identify. Canyons As was documented in 2013, the submarine canyons investigated during this expedition proved to be biodiversity hotspots, hosting many different species of coral, numerous fish species, several cephalopods (squids and octopus), and a variety of echinoderm species (e.g., sea stars, sea urchins, sea cucumbers). These canyons were generally characterized by downslope areas of soft sediment leading up to steep walls with abundant biological communities under overhangs. Evidence of anthropogenic influence was occasional, with the exception of Ryan and McMaster Canyons where D2 encountered several instances of trash and derelict fishing gear, potentially due to its proximity to shipping channels into large cities on the U.S. East Coast. Highlights from these dives include observations of deep sea predation, a series of caves inhabited by octopuses (dubbed octopus grottoes), dragonfish, and several areas of high coral density. Seamounts During our 6 dives on the New England Seamount Chain, D2 documented extensive deepsea coral and sponge habitat, patchy and often sparse fish distribution, and a variety of exciting geologic features. Seamount dives contained the highest diversity of corals of the expedition, with particularly high densities observed during our dives at Gosnold and Atlantis II. We observed several different types of lava flow, lower sediment cover with a coarser grain size compared to in the canyons, and manganese encrusting over rocks. D2 documented potential range extensions for two species of deepsea coral, previously unknown phenomena in the water column and potential new species, and collected rare imagery of deep-sea predation and behaviors. We also conducted the deepest dive to date on the New England Seamount Chain on an unnamed and previously unexplored seamount that was first mapped in high resolution using Okeanos's EM302 multibeam system in 2013. Highlights from these dives include D2's deepest dive to date, large colonies of precious corals, a dumbo octopus and vampire squid, several rare or unknown species, and areas of active coral recruitment.

Phoenix Canyon

Area

Phoenix Canyon; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 19, 2014
Max Depth:	1172.3 Meters
Bottom Time:	6 Hours 13 Minutes 6 Seconds

Purpose

The purpose of this dive is to explore the geomorphology and biology of the previously unexplored Phoenix Canyon.

Hendrickson Canyon

Area

Hendrickson Canyon; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 20, 2014
Max Depth:	1669.0 Meters
Bottom Time:	6 Hours 8 Minutes 21 Seconds

Purpose

The purpose of this dive is to explore the geomorphology and biology of the previously unexplored Hendrickson Canyon.

McMaster Canyon

Area

McMaster Canyon; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 21, 2014
Max Depth:	1358.2 Meters
Bottom Time:	6 Hours 5 Minutes 29 Seconds

Purpose

The purpose of the dive was to explore the biology and geomorphology of McMaster Canyon.

Okeanos Canyon (East of Veatch)

Area

Okeanos Canyon (East of Veatch); Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 23, 2014
Max Depth:	1517.1 Meters
Bottom Time:	5 Hours 37 Minutes 49 Seconds

Purpose

The purpose of the dive was to explore the biology and geomorphology of this minor canyon.

Retriever Seamount West Slope

Area

Retriever Seamount West Slope; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 25, 2014
Max Depth:	2142.2 Meters
Bottom Time:	5 Hours 52 Minutes 28 Seconds

Purpose

The purpose of the dive was to explore the biology and geomorphology of Retriever Seamount.

Asterias Seamount

Area

Asterias Seamount; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 26, 2014
Max Depth:	2100 Meters
Bottom Time:	n/a

Purpose

The dive was aborted before reaching bottom due to weather.

Atlantis II North West Slope

Area

Atlantis II North West Slope; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 27, 2014
Max Depth:	2746.9 Meters
Bottom Time:	8 Hours 9 Minutes 52 Seconds

Purpose

The purpose of the dive was to explore the biology and geomorphology of the Atlantis II Seamount.

Gosnold Seamount

Area

Gosnold Seamount; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 28, 2014
Max Depth:	2138.4 Meters
Bottom Time:	5 Hours 24 Minutes 42 Seconds

Purpose

The purpose of the dive was to explore the biology and geomorphology of the wholly unexplored Gosnold Seamount.

Kelvin Seamount

Area

Kelvin Seamount; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 29, 2014
Max Depth:	2075.6 Meters
Bottom Time:	4 Hours 27 Minutes 26 Seconds

Purpose

The purpose of the dive was to explore the biology and geomorphology of the Kelvin Seamount.

Unnamed Deep Seamount

Area

Unnamed Deep Seamount; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	September 30, 2014
Max Depth:	4689 Meters
Bottom Time:	3 Hours 26 Minutes 12 Seconds

Purpose

The purpose of the dive was to explore this very deep seamount. This is the deepest dive for Deep Discoverer to date.

Physalia Seamount

Area

Physalia Seamount; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	October 01, 2014
Max Depth:	2588.5 Meters
Bottom Time:	4 Hours 4 Minutes 47 Seconds

Purpose

The purpose of the dive was to explore the biology and geomorphology of the Physalia Seamount.

Ryan Canyon

Area

Ryan Canyon; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	October 04, 2014
Max Depth:	1524.4 Meters
Bottom Time:	5 Hours 25 Minutes 41 Seconds

Purpose

The purpose of this dive is to explore the biology and geomorphology of Ryan Canyon.

Nantucket Canyon

Area

Nantucket Canyon; Northwest Atlantic Ocean; Mid-Atlantic U.S. Canyons

Overview

Date:	October 06, 2014
Max Depth:	1880.8 Meters
Bottom Time:	4 Hours 38 Minutes 36 Seconds

Purpose

The purpose of this dive was to explore the biology and geomorphology of Nantucket Canyon.