The deep-sea environment into which BP operations are gradually extending is generally poorly understood with surveys regularly discovering new habitats and communities of animals previously unknown to science. There is inevitably a lack of historical data which can be used as basis for baseline knowledge and prediction. It is however apparent that all deep-sea environments support a wide range of animals that contribute significantly to global biodiversity.
By establishing long term monitoring of the deep sea physical environment and biological activity in that environment it should be possible to compensate to a large degree for previous lack of knowledge. Hitherto only two deep-sea sites in the world's oceans have been the subject of long-term studies exceeding 5 years, Station M in the NE Pacific Ocean (Smith et al. SCRIPPS Institute of Oceanography, University of California) at 4100m depth, studied since 1989 and the Porcupine Abyssal Plain (Bengal) station at 4800m in the NE Atlantic Ocean. At both stations important annual cycles have been observed with considerable variability from year to year and changes in dominant fauna over decadal time scales. In an oil production area such spontaneous changes need to be distinguished from any anthropogenic (man made) influences imposed on the deep-sea environment.
A series of scientific meetings were set up (held at the Scripps Institution of Oceanography) to discuss the feasibility of establishing a long-term monitoring station within BP operating areas. The first meeting (September 2004) concluded the establishment of a long-term monitoring station in the Atlantic Ocean would, after a minimum 3-4 year time span, begin to allow discrimination of patterns of local change that could be compared with global changes. An objective should be achievement of a 20 year time span of operation to allow monitoring for the life time of the production in the area. This would provide long-term environmental assurance but also make a major contribution to science.
At the conclusion of the first meeting Oceanlab (University of Aberdeen) were tasked with developing a number of design options to satisfy the compromise between scientific requirements and the practicalities of deploying a platform in the vicinity of BP offshore operations A further meeting of the Steering committee in April 2005 discussed and enhanced both the scientific objectives and the specification for the Oceanlab designs. The platform is now under contraction and scheduled for installation in autumn 2007.
Camera Module (Near & Far field platforms)
The camera modules contain two camera systems, a close view and wide view camera system.
Close view camera
The close view camera takes time-lapse close up photographs of the sea floor and associated fauna. In a relatively unstudied area, such as the Angolan continental slope, it is vital that we obtain good quality high-resolution images of the indigenous fauna. The close view stills camera will give us the flexibility required to correctly identify both invertebrates and fishes. We anticipate that these high-quality images will also have considerable public outreach potential as has been highlighted by the ROV images (taken with an identical camera) used as part of the SERPENT project.
Examples of high quality close view camera photographs
Wide view Camera
The wide view camera takes time-lapse photographs of a large area of the sea floor. These observations enable a visualisation of seasonal sea floor sedimentation processes, passing animals and disturbance events over a large 20m2 area. This scale of observation is essential to categorise any patterns of long-term change in the benthic environment over the 25yr life span of the project. This imaging set up has been used to excellent effect in the deep Pacific Ocean, by Dr. Ken Smith of Scripps, USA, and is proven technology. The synergy between the close view camera and the wide view camera will allow us to assess large scale and long-term patterns of diversity and community change with accurate identification of anticipated new and novel species.
An example of a time lapse wide view camera tracking a deep sea holothurians' movements across the sea floor
Oceanographic Module (Near and far field Platforms)
A suite of oceanographic instruments is essential for any long term monitoring station. They provide background measurements to fully characterise the environment for all other observation modules in the docking station.
Each oceanographic module will house
Acoustic Module (Near & Far field platforms)
Passive and active acoustics. A passive bioacoustic sensor will monitor the natural sounds generated by animals within its detection range, as well as the background noise level. This system will allow passing vocalising cetaceans to be identified (from characteristic sound spectra) and counted.
High frequency active sonar systems enable fish movements to be observed at a lower resolution but at much greater range than photographic systems. This module contains an active sonar system to record movements of fish with suitable target strength to ranges of up to 150m from the DELOS platform. In conjunction with the passive acoustic module, that records (amongst other things) background noise level, fish reaction to acoustic disturbance events could be monitored.
An example of an active sonar visualising images on the sea floor
Sediment trap module (Far field platform only)
Phytodetritus from plankton in the surface layers falls to the sea floor in seasonal pulses. This input of material is the major source of energy for the deep-sea community. A sediment trap collecting and periodically storing this fallout enables the composition and quantity of this energy input to be measured. To represent an unbiased record of phytodetrial fallout the sediment trap must be a minimum of 100m above the sea floor.
These data along with Transmissometer and Flourometer data will build up a comprehensive picture of food input into the deep ocean site.
Example of long term phytodetrital input to the deep sea caught in sediment traps showing a seasonal cycle
Guest Modules (2 guest modules in the near field platform, 1 in the far field platform)
Guest modules will initially be left empty and will be available for use in the future. Currently we have applications from both the science community and BP to use some of these modules for new research.