Okeanos Explorer (EX2304): Seascape Alaska 3: Aleutians Remotely Operated Vehicle Exploration and Mapping

Vessel: NOAA Ship Okeanos Explorer; Expedition Dates: July 14-25, 2023

Project Principals: Shannon Hoy, NOAA/OAR/OER (Expedition Coordinator)

From July 14 - July 25, 2023 (Kodiak, Alaska to Unalaska, Alaska), NOAA Ocean Exploration completed the Seascape Alaska 3: Aleutians Remotely Operated Vehicle Exploration and Mapping expedition (EX2304), a combined mapping and remotely operated vehicle (ROV) expedition exploring the deep waters around the Aleutian Islands. Operations during this 12-day expedition included the completion of eight ROV exploration dives, including six full dives and two dives that were abandoned during descent due to various circumstances. ROV dives were conducted in water depths ranging from 780 m to 2800 m for a total of nearly 27 hours of bottom time (not including mid-water transects), focusing on exploring benthic habitats (including seep communities), geohazards, and water column communities. EX2304 also collected over 15,000 square kilometers of seafloor bathymetry and associated water column data using an EM 304 multibeam sonar. All data associated with this expedition will be archived within 120 days of the end of the expedition and will be publicly available through the NOAA Archives.

Aleutians Water Column

Area

Aleutians Water Column; SW Kodiak

Overview

Date:	July 15, 2023
Max Depth:	2164 Meters
Bottom Time:	n/a

Purpose

Water column transect, samples as appropriate

Big Bend Canyon

Area

Big Bend Canyon; Big Bend Canyon ~160 km SE offshore from the Semidi Islands

Overview

Date:	July 16, 2023
Max Depth:	2324.3 Meters
Bottom Time:	5 Hours 17 Minutes 56 Seconds

Purpose

Geology, Biology, eDNA

Shumigan Scarp

Area

Shumigan Scarp; South of Aleutian islands on the continental slope

Overview

Date:	July 17, 2023
Max Depth:	n/a
Bottom Time:	n/a

Purpose

Biology, Geology, eDNA

Sanak Seep

Area

Sanak Seep; 43 mi (70 km) SW of Sanak Island on a structured portion of the continental slope

Overview

Date:	July 18, 2023
Max Depth:	2030.7 Meters
Bottom Time:	4 Hours 30 Minutes 01 Seconds

Purpose

Biology, Geology, eDNA

Lone Knoll Scarp

Area

Lone Knoll Scarp; 160 km southeast of Unalaska on a structured continental slope

Overview

Date:	July 19, 2023
Max Depth:	2807.4 Meters
Bottom Time:	2 Hours 56 Minutes 0 Seconds

Purpose

Geology, Biology, eDNA

Uliaga Mound

Area

Uliaga Mound; North of Uliaga Island

Overview

Date:	July 21, 2023
Max Depth:	n/a
Bottom Time:	n/a

Purpose

Biology, Geology, eDNA

Uliaga Mound

Area

Uliaga Mound; Mound or flat-topped pinnacle 12 miles north of Uliaga Island, within the Four Mountains area

Overview

Date:	July 23, 2023
Max Depth:	783.2 Meters
Bottom Time:	6 Hours 35 Minutes 01 Seconds

Purpose

Biology, Geology, eDNA

Umnak Canyon

Area

Umnak Canyon; Ridge at confluence of two tributaries of Umnak Canyon ~15 miles northwest of Okmok caldera on Umnak Island

Overview

Date:	July 24, 2023
Max Depth:	1479.1 Meters
Bottom Time:	3 Hours 5 Minutes 31 Seconds

Purpose

This dive targeted a water depth of 1479-1430 m to characterize deepwater communities living on a low angle ridge feature between two tributaries of the Umnak Canyon.