GB648

Area

Gulf of Mexico

Overview

Date:	April 12, 2014
Max Depth:	972.8 Meters
Bottom Time:	6 Hours 18 Minutes 51 Seconds

Purpose

Dive 1 of EX1402 L3 succeeded in achieving the two primary geological objectives set forward by the nominating organization - the Bureau of Ocean Energy Management (BOEM): 1) ascertaining whether high acoustic backscatter (from multibeam bathymetry) and linked high seafloor reflectivity (from 3D seismic/industry data) correlate with hardgrounds, and 2) determining whether seafloor locations of presumed cold seeps as deduced from the origination of ~vertical bubble stream anomalies in the overlying water column (from multibeam bathymetry) are discrete sites of gas escape. Both turned out to be true.

GB907

Area

Gulf of Mexico

Overview

Date:	April 13, 2014
Max Depth:	1266.7 Meters
Bottom Time:	3 Hours 52 Minutes 47 Seconds

Purpose

The geological objectives of dive 2, the second dive proposed by the Bureau of Ocean Energy Management (BOEM), involved: Both objectives were confirmed.

1. the search for cold seeps, escape of bubbles/oil from the seafloor as indicated by multibeam bathymetry "bubble stream anomalies", and
2. confirmation that high backscatter returns from the bathymetric high/ridge on which this dive was conducted correlated with (carbonate) hardgrounds on or near the seafloor.

Both objectives were confirmed.

NW Gulf Mid-Depth

Area

Gulf of Mexico

Overview

Date:	April 14, 2014
Max Depth:	1155.4 Meters
Bottom Time:	5 Hours 50 Minutes 7 Seconds

Purpose

The third dive concentrated on assessing mid-water coral habitats, by examining first the ~30 degree slope, then part of the crest, of a ~100 m high topographic high (part of a sinuous ridge) in depths of ~1150-1050 m. The dive was nominated by Brian Kinlan of NOAA's NCCOS, Center for Coastal Monitoring and Assessment. This dive represents the first of multiple dives designed to quantify models of deep-water coral habitats in the Gulf of Mexico.

Keathley Canyon Site KC2

Area

Gulf of Mexico

Overview

Date:	April 16, 2014
Max Depth:	2003.6 Meters
Bottom Time:	6 Hours 2 Minutes 8 Seconds

Purpose

Dive 4 was designed as a transect from the west side of the thalweg (main channel) of Keathley Canyon, in ~2,000 m, across that thalweg and upward, across two west-facing slopes and an intervening bench. The dive ended near the top of that longer second slope, in ~1760 m.

Keathley Canyon KC3

Area

Gulf of Mexico

Overview

Date:	April 18, 2014
Max Depth:	2173.1 Meters
Bottom Time:	5 Hours 28 Minutes 48 Seconds

Purpose

This Keathley Canyon dive site was ~20 km south of dive 4 in the same drainage system. This dive was nominated by Brian Kinlan/Bill Keine. The distribution and abundance of black and bamboo corals was the stated biological priority.

Keathley Canyon UTIG

Area

Gulf of Mexico

Overview

Date:	April 20, 2014
Max Depth:	2652.4 Meters
Bottom Time:	5 Hours 20 Minutes 56 Seconds

Purpose

This dive was nominated by the University of Texas, Institute for Geophysics. The focus was the westward-facing slope near the deep-water entrance to Keathley Canyon. Objectives included looking for evidence for brine escape at the seafloor, based upon subsurface seismic evidence for rising salt beneath this slope. The vehicles landed on a slight westward-facing slope at a water depth of 2,655 m, on rippled soft sediment. Until the last 15-20 min of the dive, the bottom was characterized by this type of sedimented seafloor; ripples, consistently suggesting intermittent downslope/down-canyon currents, were often present. The vehicles transited ~2.4 km over the course of the ~5.3 hr. dive, up a ~11 degree slope, across a flat bench at ~2,500 m of water, then up another ~11 degree slope until the end of the dive, at ~2,266 m of water.

Bryant Canyon Shallow

Area

Gulf of Mexico

Overview

Date:	April 21, 2014
Max Depth:	2591.4 Meters
Bottom Time:	5 Hours 16 Minutes 36 Seconds

Purpose

Dive 9 was the first of two dives along the flanks of Bryant Canyon, the easternmost of the three large drainage systems characterizing the north-central Gulf of Mexico. This dive, to examine a ridge along the "shallow" eastern flank of the Canyon, was slated for water depths of ~2,600-2,400 m. The dive was nominated by Tim Shank (WHOI) and Brian Kinlan (NOAA). The primary objective was to characterize deep-water coral habitats, and associated geologic environments.

Bryant Canyon Deep

Area

Gulf of Mexico

Overview

Date:	April 22, 2014
Max Depth:	2813 Meters
Bottom Time:	4 Hours 55 Minutes 33 Seconds

Purpose

This dive consisted of two parts: mid-water examinations at discrete depths for pelagic flora and fauna on descent, and a "deep-water" transect up the western wall of Bryant Canyon. The pelagic transect was nominated by Mike Vecchione of the Smithsonian Institution, and the seafloor dive was nominated by Tim Shank (WHOI) and Brian Kinlan (NOAA). The latter was designed to investigate potential deep-water coral habitats associated with seismic anomalies from BOEM and high backscatter areas registered by multibeam bathymetric data.

NW Gulf Deep

Area

Gulf of Mexico

Overview

Date:	April 23, 2014
Max Depth:	2879.1 Meters
Bottom Time:	4 Hours 46 Minutes 2 Seconds

Purpose

The focus of this dive was part of the wall of the Sigsbee Escarpment, from water depths of ~2,900-2,700 m. This dive was nominated by Brian Kinlan (NOAA) as true exploration. The primary goal was to characterize deep-water coral habitat, but the overall objective was to observe linked geologic and biological environments in a heretofore unvisited part of the Gulf of Mexico basin.

WR0325

Area

Gulf of Mexico

Overview

Date:	April 24, 2014
Max Depth:	1930.1 Meters
Bottom Time:	5 Hours 46 Minutes 35 Seconds

Purpose

The primary objective of the dive was to investigate a ~60 m-long sidescan acoustic target, acquired using an industry AUV, composed of two parts with ~5 m seafloor relief, which suggested a shipwreck. This dive was nominated by personnel from the Bureau of Ocean Energy Management (BOEM) and archaeologists from NOAA.

Large Mound Deep

Area

Gulf of Mexico

Overview

Date:	April 26, 2014
Max Depth:	2208.9 Meters
Bottom Time:	5 Hours 13 Minutes 17 Seconds

Purpose

The primary objective of this dive, up the wall of a prominent salient of the central part of the West Florida Escarpment, was to assess coral habitats, along with any other biology observed (see summary below). The dive was nominated primarily by Brian Kinlan and Peter Etnoyer (NOAA).

Many Mounds Deep

Area

Gulf of Mexico

Overview

Date:	April 27, 2014
Max Depth:	2096.2 Meters
Bottom Time:	6 Hours 55 Minutes 45 Seconds

Purpose

The objective of this second deep dive, from ~2100-1800 m, on the central part of the West Florida Escarpment in an overlapping but shallower depth range than Dive 13, was to complement that dive in quest to characterize deep-water coral habitats. The dive was nominated by Brian Kinlan and Peter Etnoyer (NOAA).

Many Mounds South Shallow

Area

Gulf of Mexico

Overview

Date:	April 28, 2014
Max Depth:	578.2 Meters
Bottom Time:	6 Hours 13 Minutes 43 Seconds

Purpose

The primary objectives of this shallow (~550 m throughout) dive were to characterize: 1) Lophelia and black coral associations on top of a number of mounds/bioherms known to occur in this vicinity and 2) to focus on golden crab occurrences in the vicinity of these corals. The dive was nominated as one of a series of dives in these water depths by Brian Kinlan and Peter Etnoyer (NOAA) and a team from CIOERT and Harbor Branch led by John Reed (and including Stephanie Farrington).

Many Mounds South Shallow

Area

Gulf of Mexico

Overview

Date:	April 29, 2014
Max Depth:	536.7 Meters
Bottom Time:	5 Hours 43 Minutes 35 Seconds

Purpose

Dive 16 took place north of Dive 15, in a similar water depth range (~550-470 m). The objectives were the same as Dive 15, to characterize: 1) Lophelia and black coral associations on top of a number of mounds/bioherms known to occur in this vicinity and 2) to focus on golden crab occurrences in the vicinity of these corals. The dive was nominated as one of a series of dives in these water depths by Brian Kinlan and Peter Etnoyer (NOAA) and a team from CIOERT and Harbor Branch led by John Reed (and including Stephanie Farrington).