New technologies for sanctuary research.
The Monterey Bay National Marine Sanctuary is the largest, deepest, and, ecologically speaking, perhaps the most complex in the National Oceanic and Atmospheric Administration (NOAA) Marine Sanctuary Program. Monterey Bay is also home to a unique grouping of institutions, which, taken together, comprise a powerful, growing synergy for the evolution of research technology and methods. The bay's proximity to Silicon Valley and its long tradition of classical marine research are both strong factors in this evolutionary process.
The scientific investigations of all the marine science institutions around Monterey Bay enhance the sanctuary research program. What follows are examples of new technologies under development or already at work in Monterey Bay that have significant applicability to sanctuary research, both in Monterey and around the country.
New Surface Vessels Are More Stable
Research ships provide us with basic access to our work sites. While improvements in ship design have enhanced their ability to work in rough seas and heavy weather, conventional monohulls have limited stability. To push the stability factor up a notch or two, the Monterey Bay Aquarium Research Institute (MBARI) is developing a SWATH vessel, Western Flyer (see Oceanus, Summer 1993). SWATH stands for Small Waterplane Area Twin Hull, a design that places the principal hull volume below the sea surface, and supports the main deck and interior areas on thin struts that reach up from submerged twin hulls. This greatly increases the ship's stability by reducing the hull surface area that is affected by the moving sea surface.
In the sanctuary, this innovation means that shipboard operations, from hydrocasts to submersible launches, can be conducted in higher sea states than with a comparably sized monohull. While there are benefits to having scientists working comfortably at their stations in heavy weather (instead of "painting stripes" over the side), other payoffs may not be so obvious. Greater stability also means that we will be able to investigate the ocean under conditions that previously made both ships and scientists inoperable. We can study the effects of storms on habitats and their populations in real time, instead of extrapolating from data gathered before and after storm events. The ability to conduct research on natural processes during extremes of natural conditions will go a long way toward giving us the predictive capability to deal with other sorts of sanctuary perturbations.
Undersea Vehicles Image the Depths
Three undersea-vehicle types are riding the wave of science-driven technological evolution in the Monterey region: remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), and manned (or "crewed") submersibles. The present state-of-the-art science vehicle is MBARI's ROV Ventana, which conducts daily biological and geological research in the Monterey Submarine Canyon. Starting with the basic framework of an offshore oil field ROV, Ventana was built by International Submarine Engineering in Canada to perform a variety of scientific functions.
Ventana carries a broad suite of sensors, tools, and instruments, and has a depth rating of 1,850 meters. Through its tether the ROV receives power and control instructions from the surface. At the core of the tether are optical fibers that carry computer-processed signals from sensors aboard the ROV to computers on the mother ship above. Chief among these signals are broadcast-quality video images that give the topside scientists unprecedented observational capability. Data from standard oceanographic instrumentation including recorders of temperature, salinity, depth, oxygen concentration, and light transmission are coupled to the high-resolution imagery. A scanning sonar, low-light video cameras, still cameras, a hydrophone, and a flowmeter/odometer are also aboard. Collection gear includes detritus and suction (like an underwater vacuum cleaner) samplers, a manipulator arm, and rock drills.
Integrated data from these systems offer Monterey area scientists a new perspective for studying the bay. Ventana's operational record (625 dives and more than 3,000 hours in the water over the last five years) provides high-resolution data sets. Significant work has been done with Ventana in several research areas:
* vertical transport of organic material into the deep sea,
* the geology of cold-seep sites and the biology of their resident communities,
* the fate of storm-generated drifting kelp masses,
* the role of gelatinous animals in water column ecology,
* geological effects of the 1989 Loma Prieta earthquake, and
* the importance of marine snow.
There are recent new findings in each of these areas that would have been difficult or impossible to achieve with conventional technology.
The next scientific ROV generation, presently under construction at MBARI, will have all Ventana's scientific capabilities and an operational depth of 4,000 meters, which encompasses the full vertical range of the Monterey sanctuary. In addition to its core capabilities, this vehicle will also have a variable buoyancy system, quiet electric propulsion, and removable tool sleds configured for specific tasks that can be quickly exchanged at the surface.
AUVs are currently being developed at the Navy Postgraduate School in Monterey and at MBARI. Both systems are designed to function without surface tethers. This approach reduces power requirements and allows operation during bad weather. Eliminating the tether also means that AUVs must be battery powered and that their control systems must be preprogrammed to function without a human in the loop.
AUVs offer the potential for cost-effective measurements of environmental parameters that do not require full commitment of a surface vessel. Carrying standard instrumentation, they can be programmed to "mow the lawn," that is, to run a geographical sampling grid and then return to a designated site. Alternatively, they can be programmed for periodic surface visits, to transmit data and receive new programming by radio or microwave transmission. Data transmission and reprogramming via underwater acoustic signals will add a degree of real-time control in the near future.
Additional jobs for AUVs will involve technology transfer from defense-related developments. Control systems programmed for target recognition and tracking can be used to follow fish schools or to monitor the activities of individual animals. Signal recognition software will allow an AUV to sniff out a subsurface pollutant plume, follow its concentration gradient upstream, and locate its source. Likewise, patrolling AUVs can alert us to diatom blooms linked to the neurotoxin domoic acid (produced by the diatom Pseudonitzchia australis), which has had negative effects recently on Monterey Bay bird and pinniped populations.
Technological innovation also holds new promise for crewed submersibles. At Deep Ocean Engineering in San Leandro, not far from Monterey and the contiguous Farallones Sanctuary, the next generation of crewed submersibles is under construction. Unlike most of its predecessors, Deep Flight is a small, lightweight, relatively inexpensive, one-person submersible. By incorporating new materials, new electronics, and new software, Deep Flight eschews the design philosophy that subsequent generations must be bigger, heavier, and more costly.
This approach complements the evolution of ROV and AUV technologies because for some under-sea applications there is no substitute for having the human eye and mind on site. The issues of "manned vs. unmanned" and ROV vs. AUV are moot--ultimately, we will require all three vehicle types.
Buoys and Moorings Monitor Environmental Changes
The ability to make high-resolution measurements of physical, chemical, and biological variables over time is critical to the development of reliable marine-system models. In Monterey Bay, MBARI has deployed a mooring system called OASIS (Ocean Acquisition System for Interdisciplinary Science) that makes time-series measurements of the parameters essential to understanding the variability of primary productivity.
The OASIS moorings each comprise a suite of instruments: a thermistor chain to measure temperature with depth, a conductivity-temperature-depth sensor, a fluorometer to measure chlorophyll, a transmissometer for light transmission, meteorological instruments, a spectroradiometer, that measures light at different wavelengths, an acoustic Doppler current profiler, a carbon-dioxide sensor, a PAR (photosynthetically active radiation) sensor, and such system diagnostic information as battery-power levels. Data from all of these elements is assimilated by a unique set of control electronics and telemetered in real time via packet radio or ARGOS satellite to scientists ashore.
This is an important advance in our ability to monitor environmental variables in the sanctuary or in almost any marine area. Not only does the control system provide real-time data, it also allows remote adjustment of sampling frequencies and data transmission parameters in response to changes at the site. The system is easily reconfigured with the addition or replacement of alternate sensors, and field servicing is reduced to a minimum.
The value of moored instrument arrays goes beyond traditional shipboard measurements by providing time-series data that are fixed spatially but continue temporally. Such data are vital for verifying data from satellite-borne instruments and for calibration of shipboard data sets. Sanctuary networks of instrument systems like OASIS would provide sanctuary researchers and managers with unprecedented levels of information about protected areas.
Bottom Stations Relay Changes on the Seafloor
Just as buoyed moorings can provide time-series data about water-column variability, benthic stations can give us data on the temporal variability of seafloor processes. Several Monterey Bay benthic sites are designated as continuing-research areas. Most are associated with geological features of the canyon structure that lead to slow expression of hydrogen-sulfide-rich water. These "cold seeps" are of interest to biologists as well as geologists because of the chemosynthetic communities that surround them. Using differential Global Positioning System navigation, it is easy to return regularly to these locations (at depths between 450 and 900 meters). While no permanent bottom stations are yet established, Ventana visits the designated sites regularly to collect data and to deploy and recover a variety of gear that includes larval settlement traps, a time-lapse video camera, a current meter, and a dissolved-oxygen sensor.
Long-term deployment of gear at "permanent" bottom sites has been proposed as part of the Ridge Inter-Disciplinary Global Experiments Program to study hydrothermal vent regions in the Juan de Fuca Ridge area off Washington state. Lessons learned from this program will further the development of benthic-station technology, with broad applications for deep sanctuary research programs in Monterey, the Gulf of the Farallones, and elsewhere.
Communications Permit Rapid Response
Once data has been collected, its means of transmission greatly affects its utility. In the case of the OASIS moorings, two-way communication with the instruments allows real-time response and control. In Monterey Bay, two additional technological developments are advancing the field of data communications, with obvious benefits to sanctuary researchers.
In the "live link" system, live video images from Ventana travel up the tether's optical fibers to the surface vessel, Point Lobos. Aboard the ship these images are converted to microwave signals that are transmitted ashore to antennas atop Mt. Toro. From Mt. Toro the signal is relayed to MBARI's laboratories in Pacific Grove, and to the Monterey Bay Aquarium in Monterey. These incoming signals are coupled with an audio link, and there is a counterpart outgoing audio/video signal from the shore. This two-way link allows scientists at sea to interact with colleagues ashore, and provides the lab-based researchers real-time access to the canyon environment. On many occasions this system has broadened scientific participation in a dive without sending a large contingent of scientists to sea. It is invoked each time Ventana goes to work.
At the Monterey Bay Aquarium, the live link is used for public education. Video images are projected on a screen in the auditorium, usually to a highly receptive crowd. Interpreters explain the live images to the audience, aided by a computerized catalog of information, taped video footage, and occasional comments from the scientists at sea. This allows the public to look over the researchers' shoulders as they conduct their investigations in the canyon. It is a powerful way to reach out to the public, and it could have great potential for promoting public awareness of sanctuary programs and issues.
Another communications technology under development in Monterey Bay (in conjunction with Woods Hole Oceanographic Institution engineers) is an Acoustic Local Area Network (ALAN) for real-time underwater communication. The network utilizes underwater acoustic modems for data transmission. The modems work like cellular telephones to communicate with distant computers. Pulsed acoustic signals, coded with data, control signals, or other information, travel through the water between modems.
At its present state of development, this technology can communicate at a 9,600-baud underwater data rate. This is fast enough to support electronic mail via the UNIX computer operating system, and can transmit single-frame video or sonar images at 3- to 4-minute intervals. This technology has great potential for enhancing a network of sanctuary research applications. Through ALAN, a variety of instrument packages and sensors--aboard vehicles, on moorings, and deployed at bottom stations--could communicate with one another to coordinate activities among stations and with researchers ashore for real-time control and data retrieval.
While the technology of pulsed acoustic communications is still in the early development stage for network-level use, point-to-point use by the US Navy's AUSS (Advanced Unmanned Search System) autonomous vehicle has been very successful. Developing a network on the scale of Monterey Bay is challenging, but it may prove to be an enabling technology that links all of the other technologies described into a system that transcends their individual value.
Other Technologies Are Lowering Costs and Opening New Doors
Technological development by research institutions around Monterey Bay goes well beyond the examples discussed here, including new chemical sensors, undersea navigation systems, satellite links, new tools for undersea vehicles, biotechnology, and new data management systems. Most of these developments are science-driven and are coupled to the evolution of new research methodologies.
The value of these new and emerging technologies for sanctuary research is essentially twofold. First, they offer the means to gather and manage more data, precisely and reliably and at lower cost than conventional technologies allow. Second, and perhaps most important, these technologies provide new kinds of information that bring new perspectives to old problems and enable researchers to make the conceptual progress necessary to better understanding of natural systems. These technologies are evolving rapidly. Virtually everything discussed here already is or by 1998 will be operating within the Monterey Bay Marine Sanctuary. What the future holds should be even better. Stay tuned....
Bruce H. Robison is Senior Scientist and Science Department Chair at the Monterey Bay Aquarium Research Institute. He began college with the goal of becoming an aeronautical engineer--ten years and five majors later he received a Ph.D. from Stanford University in biological oceanography. He uses both crewed and remotely operated vehicles for his research on the ecology of deep sea animals.
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|Author:||Robison, Bruce H.|
|Date:||Sep 22, 1993|
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