Okeanos Explorer (EX1504L3): CAPSTONE Leg III: Main Hawaiian Islands and Geologists Seamounts (ROV/Mapping)

Vessel: NOAA Ship Okeanos Explorer; Expedition Dates: August 28 - September 3, 2015

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

The ship will conduct 24 hour operations consisting of daytime ROV dives and evening/nighttime mapping operations including during transit. During this cruise we will conduct 8 hour ROV dives on most days with occasional 10 or 12 hour dives (at the ship's discretion) on particularly interesting or deep dive sites. ROV operations will focus on depths between 350 and 3,000 meters and will include high-resolution visual surveys and limited sample collection. Mapping operations will be conducted in 250 m of water and deeper, and include overnight multibeam, water column backscatter, and sub-bottom data collection. Opportunistic CTD rosette operations may be requested to collect more information about the environmental parameters at ROV dives sites, or opportunistically at selected sites where collecting the data is considered important to understanding the physical or chemical properties of the overlying water column.

Makapuu Precious Coral Bed

Area

Makapuu Precious Coral Bed; North Pacific Ocean; Main Hawaiian Islands

Overview

Date:	August 28, 2015
Max Depth:	n/a
Bottom Time:	n/a

Purpose

The dive was aborted at the surface immediately after deployment.

Kona Precious Coral Bed

Area

Kona Precious Coral Bed; North Pacific Ocean; Main Hawaiian Islands

Overview

Date:	August 29, 2015
Max Depth:	393.7 Meters
Bottom Time:	6 Hours 46 Minutes 52 Seconds

Purpose

This dive targeted the middle of the Keahole precious coral bed off the Kona Coast of the Big Island of Hawaii. The objectives were to (1) recover an acoustic current meter and three flow meters placed throughout the bed, (2) to make observations on nearby previously marked colonies, and (3) to spend the remaining time exploring the surrounding environment. Most of the Keahole bed is carbonate ledge habitat and this dive was intended to spend much of the dive time working the top edge of the drop off.

South Kona transect of 1868 lava flow

Area

South Kona transect of 1868 lava flow; North Pacific Ocean; Main Hawaiian Islands

Overview

Date:	August 30, 2015
Max Depth:	454.9 Meters
Bottom Time:	6 Hours 54 Minutes 2 Seconds

Purpose

This dive was the first use of the D2 to conduct a standardized survey of corals along a 450 contour at the southern end of the Kona Coast of the Big Island of Hawaii. The intent was survey a lava flow of a known age (1868) and see what coral community had grown in the years since the flow had formed. The objectives were to (1) travel a 2000 meter distance with the video recording a fixed wide frame with occasional snap zooms to verify coral taxa, (2) to use the laser scale to estimate the size frequency of the coral colonies encountered on the transect, and (3) to collect two basalt samples to verify the material and the age of the lava flow.

McCall Seamount

Area

McCall Seamount; North Pacific Ocean; Main Hawaiian Islands

Overview

Date:	August 31, 2015
Max Depth:	2715 Meters
Bottom Time:	4 Hours 54 Minutes 47 Seconds

Purpose

This dive was the first ever conducted on McCall Seamount in the group of topographic features referred to as the Geologist Seamounts. The dive surveyed the crest of a sharp ridge that extended north of the seamount at a depth of 2700 m. The survey employed the standard methodology of the D2 with the objectives of 1) making observations and collecting video and 2) collecting rock and biological samples.

Swordfish Seamount

Area

Swordfish Seamount; North Pacific Ocean; Main Hawaiian Islands

Overview

Date:	September 01, 2015
Max Depth:	1077.2 Meters
Bottom Time:	6 Hours 50 Minutes 41 Seconds

Purpose

This was the first dive ever conducted on Swordfish Seamount located in the Geologist Seamounts group. The objective of this dive was to survey the ridge shaped summit for corals and sponges, testing the hypothesis that high density communities can be found on ridge topography. Discovery of high density communities at this dive site will provide valuable information to NOAA's Deep Sea Coral and Technology Program (DSCTP).The dive plan was to survey the upper crest at a depth of approximately 1000m, which is within the Hawaii's oxygen minimum zone although the islands don't quite reach the strict definition of below 0.5 ml/l to be an OMZ. The survey employed the standard methodology of the D2 with the objectives of 1) making observations and collecting video and 2) collecting rock and biological samples.

Ellis Seamount

Area

Ellis Seamount; North Pacific Ocean; Main Hawaiian Islands - Geologists Seamounts

Overview

Date:	September 02, 2015
Max Depth:	2153.1 Meters
Bottom Time:	4 Hours 30 Minutes 21 Seconds

Purpose

This was the first dive ever conducted on Ellis Seamount located in the Geologist Seamounts group. The objective of this dive was to survey a rift zone ridge coming off the northern end of the seamount for corals and sponges, testing the hypothesis that high density communities can be found on ridge topography. Discovery of high density communities at this dive site will provide valuable information to NOAA's Deep Sea Coral and Technology Program (DSCTP).The dive plan was to survey the ridge crest at a depth of approximately 2100m. The survey employed the standard methodology of the D2 with the objectives of 1) making observations and collecting video and 2) collecting rock and biological samples.

S19 Submarine Site

Area

S19 Submarine Site; North Pacific Ocean; Main Hawaiian Islands

Overview

Date:	September 03, 2015
Max Depth:	402.9 Meters
Bottom Time:	2 Hours 51 Minutes 37 Seconds

Purpose

This dive will visit the hull of the World War I submarine S-19 which now rests on the bottom at 414 m in the middle of a sand expanse. After service in World War I the vessel was no longer needed and was intentionally scuttled by the Navy in 1938 and now serves as a relatively new feature of hard bottom habitat (~75 yrs old) for deep corals to colonize. The hull, which is intact, provides a unique glimpse of a community of pioneer settlement in deep corals. The objectives of the dive are to (1) recover a flow meter placed on the stern of the S-19, (2) to make observations on the condition of the vessel to support information on submerged cultural resources and (3) practice deploying and recovering a mock-up of a tilt meter instrument.