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Motivation

In marine habitats worldwide, the zone between scuba-diving depths (to 40 m) and surge-free depths (below 200 m) has been poorly studied. Remotely operated vehicles (ROVs) are often limited to deeper depths by wave surge that hampers the ability to maintain a fixed station. Under ice-covered seas, wave motion is minimal to nonexistent, and the zone between 40 and 200 m is accessible to ROVs. Polar marine research has the benefit of stable sea ice platforms for staging and deploying instruments like ROVs, but this requires a hole in the ice. For ROVs in use today, the minimal diameter of an ice hole is a meter. This large size hole requires considerable logistic support and time to make. They are therefore expensive, limited to regions near logistic centers, and offer one to only a few holes for ROV deployment.

thumbnail of scini model This schematic of SCINI was created with SolidWorks and allows us to carefully check how components will fit together. Because SCINI has such a small diameter, it's critical, and sometimes difficult, to squeeze everything in.

This proposal develops an ROV that can be deployed through a 15 cm hole in the ice. This small size hole can be drilled with a hand-held power head, requiring minimal logistical support and technical expertise. It is a simple matter to drill many holes in the ice so that the ROV can be used to survey very large areas of overlapping seafloor. The new ROV also provides access to regions that remain unstudied because of their distance from logistical support and safety considerations, expanding our scientific reach and ability to address new questions. We will develop, test, and modify the ROV while accomplishing three overlapping and interdependent science objectives.

Dr. Paul Dayton emplacing experimental cages on the seafloor near McMurdo Station in 1967. Photo courtesy of PKD. Dr. Paul Dayton deploying a cage experiment on the seafloor in McMurdo Sound in 1967. Notice his diving gear - he is using a double hose regulator (in use in the USAP until 1988) and a WETSUIT, in water that is -1.8 C (29 F)!

First, we will locate historical experimental structures on the sea floor around McMurdo Station. In the early years of subtidal Antarctic research, there were no depth limits for scuba diving, and research was conducted at depths to 60 m. The experiments initiated starting in the late 1960s by Paul Dayton and John Oliver are still in place, but the safe diving depth limit of 39 m thwarts access to the deeper ones without an ROV. Over the last 40 years, nearly 100 artificial substrates and structures have been colonized by many species of sessile invertebrates. This provides an unprecedented opportunity to explore and document the rates and patterns of ecological succession from one of the most extreme coastal habitats in the world. We will locate the structures with the new ROV, document their positions with GPS, and photograph the ecological communities with still and video cameras equipped with laser scalers, which permit the definition of sample area and animal size for various quantitative measurements. These images and the site location will permit researchers to revisit and compare each experimental substrate in future work.

An example of Anoxycalyx (Scolymastra) joubini growing at 30 m water depth in McMurdo Sound. Laser dots (darkened for visibility) are 20 cm apart; overall organism height is 44 cm. This individual volcano sponge, Anoxycalyx joubini, is 44 cm high and is growing on a substrate that was emplaced 46 years prior. The growth rate of approximately 1 cm/year is unexpectedly rapid for an Antarctic species. The dark spots emphasize laser scalers that were used to measure the size of the sponge.

Next, we will use the new ROV to survey two unique benthic habitats and communities beyond scuba-diving depths (at 40-170 m), which are almost completely unknown to most researchers. We will mosaic individual photographs into very large spatial scale (20 to 50 m on a side) high-resolution images of the seafloor. This will permit complete testing and development of the ROV for deep-water searching and sampling, a primary future use of the ROV. Finally, we will test protocols for conducting sonar mapping with the new ROV. If flight controls are adequate, this will be the first step towards creating high-resolution, continuous bathymetric maps of the entire seafloor around McMurdo Station. These maps are similar in definition to aerial photographs on land, and are the highest priority for benthic ecological research in any environment where they can be produced. The ROV will usher in a new era of benthic exploration in McMurdo Sound, as similar tools have done in Monterey Bay.

Deploying the beta one ROV for a test dive in Antarctica. The prototype was deployed and recovered smoothly through 6 m of ice. Drill power head and bits in foreground can be easily operated by 1-2 people Deploying the beta one ROV for a test dive in Antarctica. The prototype was deployed and recovered smoothly through 6 m of ice. Drill power head and bits in foreground can be easily operated by 1-2 people

During previous research projects at McMurdo, we did preliminary testing and proof of concept work for this project. The beta one prototype was 11.5 cm diameter and 1.2 m length, with 3 tunnel thrusters for maneuvering and depth control and an aft thruster for propulsion. The ROV will be constructed as modules; this allows flexibility to change the ROV capabilities to suit different missions. For the proposed project the modules will consist of a domed camera module in the front with forward vertical pitch and horizontal yaw thrusters, the forward electronics/navigation bottle and floatation module, the aft electronics/payload bottle with aft pitch and yaw thrusters, and finally the main aft thruster. The camera and electronics bottles will be three separate water tight pressure housings interconnected by SeaCon electrical connectors. Some components can be purchased off the shelf (e.g. VideoRay high resolution and low light video cameras), and the project will require development of some custom integration software. Power is provided from the surface via a 2 conductor tether; bi-directional high speed data is modulated on the tether as well, providing 84 mbs of data and unlimited dive duration. This bandwidth is more than sufficient to allow the transmission of video, control signaling, instrumentation and navigation position data. The topside controls consist of a laptop computer and joystick for the pilot. The main video will be displayed on the computer screen and recorded to hard drive. A second computer is networked into the system to provide backup and a navigators position if necessary.

Our education and outreach efforts include hosting a PolarTREC teacher, Mindy Bell, and creating an interactive experiment with Second Opportunity School. Two undergraduate students, Nick Huerta and Bryan Newbold, are participating fully in the project, including deploying to Antarctica. Several other Antarctic scientists have indicated a strong interest in utilizing this tool in their research and we hope it will be utilized by many researchers for many different purposes when we have completed development.

This material is based on work supported by the National Science Foundation under Grant No. ANT-0619622 (http://www.nsf.gov). Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
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