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An Exploration into Crustal Subsidence Recorded on the San Juan Seamount
Robin L. Banner and Dr. Leslie R. Sautter
Abstract:
The San Juan Seamount lies off the coast of Southern California with its shallowest depth at 560 m. The volcanic seamount exhibits rough ridges trending northeast-southwest. The majority of California Borderland seamounts are smooth and sediment covered, whereas the San Juan Seamount is one of the few to exhibit weathered grooves and worn rocks. Several ROV Tiburon dives by Monterey Bay Aquarium Research Institute researchers in 2003 and 2004 explored the seamount and collected 102 rock samples. Those dives revealed numerous sub-aerial features such as coastal cliffs and cobble beaches. A12 kHz multibeam sonar also surveyed the seamount and detected a slight break in the seamount's slope at a depth of 700 m, suggesting that the San Juan Seamount was an island before it subsided by between 550 and 700 m, likely since the Late Miocene. In 2011, the NOAA Ship Okeanos Explorer conducted a survey of the seamount and adjacent abyssal region using a Kongsberg EM302 multibeam sonar. These data have been processed using CARIS HIPS & SIPS 7.1 to produce a CUBE BASE Surface and backscatter mosaic to reveal new insights into past crustal subsidence. Distinct discontinuities in seabed gradient and the extent of gravel have been identified.

Geomorphologic Analysis of Baltimore and Wilmington Canyons on the United States Mid-Atlantic Slope
Samantha M. Bruce and Dr. Leslie R. Sautter
Abstract:
Wilmington and Baltimore Canyons, located 140 km south-east of Delaware Bay along the U.S. Mid-Atlantic Slope, were explored in 2011 and 2012 by the NOAA Ships Okeanos Explorer and Nancy Foster. A Kongsberg EM302 (Okeanos Explorer, 2011 and 2012) multibeam echosounder was used to survey the region, and a Kongsberg EM1002 (Nancy Foster, 2011) was used to survey the Baltimore Canyon area. CARIS HIPS 7.1 software was used to process and analyze the sonar data and depict the bathymetry of the area. Slumps and evidence of turbidity flows within the submarine canyons were documented, and the region's geomorphology was characterized to inform marine spatial planning efforts specifically related to the management of deep water corals and demersal fish that inhabit rocky substrates.

Bathymetric analysis of the northwestern Channel Islands Slope
Angela M. Dapremont and Leslie R. Sautter
Abstract:
The Channel Islands are a series of land masses situated between the Patton Escarpment and the coast of southern California. Five of the eight islands make up the Channel Islands National Park which spans fewer than 400 square miles. All of the islands are considered to be located in a region known as the California Borderlands. This broader area is a continental slope that is separated from the continental shelf by the islands. The Borderlands area is known to be seismically active, with numerous offshore faults, as well as basins and ridges that trend in a northwest-southeast direction. The islands themselves contain varying topographic and geologic features including steep mountains and marine terraces, and several are prone to landslides, as well as coastal erosion. Bathymetric data were obtained in 2011 from the NOAA Ship Okeanos Explorer with a Kongsberg EM302 multibeam echosounder, and processed using CARIS HIPS and SIPS 7.1 software. This bathymetric investigation focused on the northwest geographic region of the Channel Islands in order to provide a more accurate characterization of specific features present. BASE surface generation (depth range of 200 to 2000 m) revealed the presence of old and young features, as well as slumping and material transport pathways.

Geomorphic Analysis of the Galapagos Spreading Center
Willie Edwards and Dr. Leslie Sautter
Abstract:
Multibeam sonar data of the Galapagos Spreading Center were obtained by the Scripps Institution of Oceanography in 2010 from aboard the R/V Melville. Surveys were conducted using a Kongsberg EM122 and processed using the CARIS HIPS & SIPS 7.1.2 software. The Galapagos Islands sit over the Galapagos hotspot, a complicated geologic setting close to the boundary between the Cocos and Nazca Plates. The Galapagos Spreading Center is located just north of the island cluster. Bathymetry and morphology of the spreading center were observed and analyzed in an attempt to understand and characterize the region's geomorphological history. Research associated with this area will be beneficial to the understanding of hot spots and related seafloor tectonic features and deep sea volcanism, as well as being potentially useful for benthic habitat characterization.

Bathymetric Analysis of Continental Shelf-Edge Marine Habitat off the Coast of Charleston, SC
Kyle W. Ford, M. Montgomery Taylor, Leslie R. Sautter, and Scott Harris
Abstract:
A delta-like feature was identified at the continental shelf edge, 85 km southeast of Charleston, SC and named the Geneva Delta. This feature may once have been an active river delta during a lower stand of sea level approximately 30 meters below present day. Bathymetric data were collected by College of Charleston BEAMS Program students during a research cruise in May 2012 aboard the NOAA Ship Nancy Foster using a Reson 7125 multibeam system. The survey area ranges in water depths from 40 to 70 meters. Three-dimensional imagery and cross-sectional profiles were generated using CARIS HIPS and SIPS 7.1. Analysis of these images revealed areas of low relief interspersed with rocky outcrops. Additionally, a variety of fish and marine invertebrates was observed, including the invasive species, Pterios volitans, commonly known as the lionfish. The morphological features identified indicate habitats that are of particular interest to the commercial fishing industry. These data are crucial to understanding essential fish habitats on the southeast continental margin in order to determine potential locations for establishing Marine Protected Areas.

Geomorphologic Impact on the Climate Record of Santa Cruz Basin, CA
Christina Hefron, Tyler Wheelus, and Dr. Leslie R. Sautter
Abstract:
Part of the California Borderlands, the Santa Cruz Basin is located off the southern California coast approximately 87 km west of Los Angeles. The basin reaches a depth of 1957 m and covers an area approximately 1735 km², trending northwest to southeast. Similar to the anoxic Santa Barbara Basin, the Santa Cruz Basin contains varves with a foraminiferal climate record dating to the Miocene. During March 2011 the NOAA Ship Okeanos Explorer collected multibeam sonar data of the basin using a Kongsberg EM302 multibeam sonar system. CARIS HIPS 7.1 software was used to create a high-resolution CUBE BASE bathymetric surface and three dimensional map of the basin's geomorphology, which revealed slumps and turbidity flows from the nearby Santa Cruz Canyon. The drainage system, canyon turbidity flows, and slumping have potentially disturbed the climate record along the edge of the basin floor. As with nearby basins, the right-lateral movement caused by transform faults of this region may be responsible for the slumping along the western rim of the Santa Cruz Basin. Along the eastern rim of the basin, a dendritic drainage system was identified as an outlet for the Pilgrim Banks which divides the Santa Cruz Basin from neighboring Santa Monica Basin.

Bathymetry of Cayman Trench, between the Cayman Ridge and Nicaragua Rise
Taylor M. Intaphan and Dr. Leslie R. Sautter
Abstract:
The Cayman Trench (or Trough) is located in the Western Caribbean Sea between Jamaica and the Cayman Islands. The site is renowned for geologic complexity; it is both a transform fault zone and a 'pull-apart' basin which produces many geological features. Within the trench lies a spreading zone, at a depth of between 4000 and 5000 m, bordering the North American and Caribbean Plates. Bathymetric data were gathered using Kongsberg EM302 multibeam sonar aboard the NOAA Ship Okeanos Explorer in 2011, and processed using CARIS HIPS and SIPS 7.1 to illustrate bathymetry of the Cayman Trench region. These data show the longitudinal profile of the Cayman Trench as well as the trench's rise, to the south. A bathymetric 3-D map of the Cayman Trench provides information that hydrogeologists and geophysicists can use; the detailed bathymetry identifies essential sites to better understand the subsurface geology.

Geomorphic Characterization of Seafloor Classification: Gray's Reef National Marine Sanctuary
Friedrich Knuth, Leslie R. Sautter and Greg McFall
Abstract:
Gray's Reef National Marine Sanctuary (GRNMS) is located on the continental shelf of the southeastern US, 32.4 km east of Sapelo Island, Georgia. The sanctuary covers approximately 58 km², with average depths ranging between 14.8 to 22 m. In May, 2011, the NOAA Ship Nancy Foster collected bathymetric and backscatter data for the reef using a Reson 7125 multibeam sonar system. These data were processed in CARIS HIPS 7.1.2 to map the bathymetry at a 2m resolution, and backscatter at 1m resolution. Cross-sectional profiles indicate sand waves are potentially encroaching on the colonized hard bottom reef. Backscatter values roughly correspond to previously identified main bottom types found in Gray's Reef: flat sand, ripples sand, densely colonized hard bottom and sparsely colonized hard bottom. This study provides a baseline for comparison to earlier benthic surveys and can aid in future management decisions for the sanctuary.

Bathymetric Analysis of the Southern Portion of the Mid-Atlantic U.S. Continental Margin
Per W. Lorentzen, Samir Younes, and Dr. Leslie Sautter
Abstract:
Multibeam sonar data were collected by the NOAA Ships Okeanos Explorer (June, 2011 and November, 2012) and Nancy Foster (June, 2011) during three cruises to acquire high-resolution bathymetric and backscatter data of the continental slope due-east of the northern portion of the Outer Banks, North Carolina and southern Delaware coastlines. Kongsberg EM302 multibeam sonar was used, and bathymetric and backscatter data were processed using CARIS HIPS & SIPS 7.1 software. Surveys were run parallel to the shelf edge, ranging in depth from 100 to 3000 m. This area has some of the steepest gradients of the United States east coast. The shelf is well incised by many medium-sized submarine canyons in close proximity of each other as well as the large Norfolk and Washington Canyons that characterize the slope and rise. High-resolution bathymetry can help with predicting areas where tsunamis may occur as a result of major sediment slumping. The continental rise is seldom the focus of mapping projects, but within our data are three examples of sediment travelling from shelf to rise.

Bathymetric Analysis of the Monterey Canyon using Multibeam Sonar
Charles McHugh and Dr. Leslie Sautter
Abstract:
The bathymetry of the Monterey Canyon, located off the coast of Monterey, California, was mapped using multibeam sonar. The Monterey Canyon extends 146 kilometers offshore with a vertical relief of nearly 3600 meters, greater in width and relief than the Grand Canyon. Each year the Canyon serves as a conduit to hundreds of thousands of cubic meters of sediment that barrels downslope between its walls. In the past, these turbidity currents have destroyed expensive scientific sensors. In order to better understand turbidity currents and their behavioral patterns, a detailed bathymetric map and numerous cross-sections of the canyon seafloor were created using data collected in 2011 by the NOAA Ship Okeanos Explorer equipped with Kongsberg EM302 multibeam sonar. Bathymetric data were processed using CARIS HIPS & SIPS 7.1 post-processing software. This study will add to our knowledge of turbidity currents and their processes, which might prevent future damage to instruments vital to research.

Bathymetric Study of Four Submarine Canyons on the Southern Edge of Georges Bank
Savannah Norvell, and Dr. Leslie R. Sautter
Abstract:
Georges Bank is a large submerged plateau, encompassing an area of 42,000 m² on the northeastern continental shelf. On its seaward boundary it is incised by several submarine canyons, which play a significant role in the high levels of productivity that have historically characterized the area. Marine organisms thrive in submarine canyons, and recent approaches to protect fish populations have emphasized the importance of these benthic habitats. Raw bathymetric data were acquired with a Kongsberg EM302 multibeam sonar system from aboard the NOAA Ship Okeanos Explorer in 2012 during a five-leg survey of the U.S. Atlantic Margin. Four of the submarine canyons surveyed have been processed and analyzed in this study with the CARIS HIPS 7.1 software: Hydrographer Canyon, Oceanographer Canyon, Gilbert Canyon, and Lydonia Canyon. These data have been used to predict coral habitats on the basis of canyon depth, relief of canyon walls, and location of hard substrate. Gaining a clearer insight about the continental shelf and slope morphology of the Georges Bank area will aid in ecosystem management.

Bathymetric and Morphologic Analysis of the Mississippi Slope
Harris Pantlik, Matthew Hughes, and Dr. Leslie Sautter
Abstract:
Multibeam sonar and backscatter data were collected in August, 2011 aboard the NOAA Ship Okeanos Explorer along the Mississippi continental slope, 70 km southeast of the Mississippi River Delta. Data were collected using a Kongsberg EM302 and were processed with CARIS HIPS 7.1. This region has been heavily investigated by the petroleum industry and academia due to its archetype marine petroleum-bearing basin. Bathymetric data yielded high resolution images of several geomorphologic features, including wave-cut terraces, salt diapirs, large scale slumps, gas vents, sediment fan lobes and other structures formed during the Late Pliocene. Evidence of salt piercement was found on the Biloxi Dome while a large slumping mass can be identified on the southern margin of the Mitchell Dome. The southern margins of several other domes exhibit small amounts of slumping.

Predictive habitat modeling of a submarine ridge off of the West Florida Escarpment
Matthew Rittinghouse; Dr. Leslie R. Sautter; Dr. Peter J. Etnoyer
Abstract:
Habitat modeling offers a useful tool for deep-sea exploration planning and a cost-effective approach to deep-sea ecosystem management. Challenges to these techniques include the appropriate scale of analysis, availability of data, definition of predictor variables, and potential for model verification. In August 2012, the R/V Falkor collected high resolution bathymetry data along the West Florida Escarpment, using Kongsberg EM710 and EM302 multibeam echosounders. A ridge feature near the shelf break (400-650 m depth) had been previously mapped by the NOAA Ship Okeanos Explorer in April 2012.Video transects conducted by the Global Explorer MK3 ROV revealed a diverse assemblage of deep-sea corals and associated organisms. Habitat forming corals, such as Lophelia pertusa, Leiopathes sp., Plumarella sp., and Stylaster sp., were observed.
The goal of this work is to use CARIS HIPS 7.1, BASE Editor 4.0, and ArcGIS 10.1 to generate a mesoscale predictive habitat model based on observed species distributions, substrate character, and bathymetry. This predictive model will be used to assess the areas with greatest potential for conservation and future research.