Long-term (~1-year) imagery records of methane seep and hydrothermal vent sites are very rare, as are images of the upper water column in the NE Pacific. Yet the information that digital images can provide is crucial to understanding life in deep water and coastal environments. There is little information about how bacterial and clam communities at methane seeps change over time, or how animal communities at vent sites change at temporal scales of minutes, hours, and days.
Imagery for OOI is collected to support a wide range of science questions, from geology to biology. Subjects of interest include changes in megafauna population density and activity, details of microbial mat, vent and seep flow rates and shape changes over time, and sedimentation processes. The cameras need the ability to image the sediment surface in sufficient detail to identify organisms (e.g., sea pens, fish, crustaceans, etc.), determine the presence/absence and changes in physical bedforms like ripples in the sediment, and identify biogenic features such as tracks and trails made by mobile fauna. Color images are required to assist with organism identification and to image phytodetritus flux to the seafloor.
Cameras that are attached to the electro-optical cable infrastructure (Endurance Oregon sites at 80 and 600 m depth, on the seafloor at Axial Seamount and Hydrate Ridge, and in the water column on profiler platforms at 200m depth) have the potential to increase the image capture rate during seismic activity, anoxic incidents, plankton blooms, or storm events to observe short-term changes in seafloor populations and features.
Cameras are installed at a diffuse flow site in the International District hydrothermal field within Axial Volcano’s caldera (Site MJ03C), along with a vent fluid and DNA sampler and a mass spectrometer. This allows time-series measurements of fluid, temperature, and chemistry correlated to video imagery of changing animal and environmental conditions for the first time. The camera can take a high-definition still image every 1 second! Another camera is installed at the active methane seep site called ‘Einstein’s Grotto” at Southern Hydrate Ridge.
Reference Information
- The OOI cameras are currently a mix of models:
- All of the cabled units (instrument code CAMDS-B and CAMDS-C) are now SubC Rayfins with Aquorea LED lamps and ROS PT-25 pan & tilt units. 2019 was the first deployment of Rayfins on the midwater mooring platforms (200 meters depth at Oregon Continental Margin and Axial Base). 2020 was the first deployment of Rayfins at the seafloor sites (Oregon Shelf, Oregon Offshore, Hydrate Ridge, and International District Vent Field on Axial Seamount).
- The uncabled cameras are modified Kongsberg 0484-6002 Color Digital Still Cameras and 2x OE11-150 Lamps, which provide 5 MPixel images with a 55° diagonal field of view.
- Each camera and computer controller (along with onboard data storage and battery power in the case of cameras on uncabled infrastructure) are contained within a watertight pressure housing constructed of titanium, which minimizes corrosion.
- All still cameras require additional lighting to reliably capture color images. The lights are attached to a crossbar that angles them at ~45 degrees from the camera lens (with respect to the field of view), and the dimmable LED lamps have a 68° beam and luminous output of 1,480 lumens with a color temperature of 3,100k and typical CRI of 80.
- Cameras on the cabled infrastructure have pan & tilt capability, which allow the camera to be aimed at a specific object or to correct the field of view in case the camera mounting is bumped or shifts during deployment.
- A Laser Reference Unit is mounted externally, directly above the camera, and projects parallel beams of red (635nm) light, allowing for accurate size classification of objects in the field of view.