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Publications (14)0 Total impact

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    ABSTRACT: We describe the design, testing, and performance of an actively controlled deep-sea Free Ocean CO2 Enrichment (dp-FOCE) system for the execution of seafloor experiments relating to the impacts of ocean acidification on natural ecosystems. We used the 880 m deep MARS (Monterey Accelerated Research Initiative) cable site offshore Monterey Bay, California for this work; but the Free Ocean CO2 Enrichment (FOCE) system concept is designed to be scalable and can be modified to be used in a wide variety of ocean depths and locations. The main frame is based on a flume design with active thruster control of flow and a central experimental chamber. The unit was allowed to free fall to the seafloor and connected to the cable node by remotely operated vehicle (ROV) manipulation. For operation at depth we designed a liquid CO2 containment reservoir which provided the CO2 enriched working fluid as ambient seawater was drawn through the reservoir beneath the more buoyant liquid CO2. Our design allowed for the significant lag time associated with the hydration of the dissolved CO2 molecule, resulting in an e-folding time, τ, of 97 s between fluid injection and pH sensing at the mean local T=4.31±0.14 °C and pHT of 7.625±0.011. The system maintained a pH offset of ~0.4 pH units compared to the surrounding ocean for a period of~1 month. The unit allows for the emplacement of deep-sea animals for testing. We describe the components and software used for system operation and show examples of each. The demonstrated ability for active control of experimental systems opens new possibilities for deep-sea biogeochemical perturbation experiments of several kinds and our developments in open source control systems software and hardware described here are applicable to this end.
    Deep Sea Research Part I: Oceanographic Research Papers. 11/2014;
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    ABSTRACT: A series of Free Ocean CO2 Enrichment (FOCE) experiments are underway or are in planning to perform in situ ocean acidification research at a number of locations around the world. One of the most challenging locations is in Monterey Bay at the site of the Monterey Accelerated Research System, the United States test facility for cabled observatories. This site is located at 890 m deep and 4 0C within the local oxygen minimum zone and approximately 50 kilometers from shore. At this depth and temperature the behavior of liquid CO2 presents various challenges that had to be addressed in order to provide the low pH seawater needed for the FOCE apparatus to perform as desired. To solve this challenge a team of engineers and scientists at the Monterey Bay Aquarium Research Institute (MBARI) have developed a standalone device referred to as the Enriched Seawater Delivery System. Simple injections of seawater saturated at one atmosphere with CO2 demonstrated that the FOCE unit itself performs as designed. However, providing a consistent source of CO2 enriched pH altered seawater within the design criteria proved to be an imposing problem which when solved could have a broader impact in the oceanographic community. The decision was made to build a stand-alone device separate from the FOCE flume to perform in situ CO2 experiments in conditions where CO2 hydrate can form. Challenges to be over-come by this work included: (1) liquid CO2 is buoyant at the prescribed depth; (2) minimizing the formation of hydrates while manufacturing the CO2 enriched seawater. Because CO2 hydrate is denser than seawater, management of the phases and stability of liquid CO2 was necessary to prevent clogging within the delivery system. Our earliest field experiments demonstrated that containing and controlling the CO2 and the CO2-enriched seawater is difficult and makes the metering of the enriched fluid with on demand milliliter per second precision an extremely challenging problem. The Enriched Seawater Delivery system is currently deployed and operating successfully in the Monterey Bay. The unit is expected to deliver CO2 enriched seawater for approximately 4 weeks with each 200 liter load of liquid CO2 to the FOCE experiments and providing a -0.3 pH offset for over a year with regular (monthly) refills. We outline the science requirements, the technical challenges, and engineering implementation required to accomplish enriched seawater delivery from the system. We present data demonstrating the desired pH offsets as a function of the FOCE internal water velocity and the deep-sea performance to date.
    AGU Fall Meeting Abstracts. 12/2011;
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    ABSTRACT: The kinetics of the reaction that occurs when CO2 and seawater are in contact is a complex function of temperature, alkalinity, final pH and TCO2 which taken together determine the time required for complete equilibrium. This reaction is extremely important to the study of Ocean Acidification (OA) and is the critical technical driver in the Monterey Bay Aquarium Research Institute's (MBARI) Free Ocean CO2 Enrichment (FOCE) experiments. The deep water FOCE science experiments are conducted at depths beyond scuba diver reach and demand that a valid perturbation experiment operate at a stable yet naturally fluctuating lower pH condition and avoid large or rapid pH variation as well as incomplete reactions, when we expose an experimental region or sample. Therefore, the technical requirement is to create a CO2 source in situ that is stable and well controlled. After extensive research and experimentation MBARI has developed the ability to create an in situ source of CO2 enriched seawater (ESW) for distribution and subsequent use in an ocean acidification experiment. The system mates with FOCE, but can be used in conjunction with other CO2 experimental applications in deep water. The ESW system is completely standalone from FOCE.
    01/2011;
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    ABSTRACT: Using the well developed Deep Ocean Raman In Situ Spectrometer (DORISS), we have developed an in situ deep-sea marine sediment pore water probe for geochemical studies. This novel device allows detailed measurement of pore water profiles. Our particular interest is in dissolved CH4, SO4 = , H2S, and pH in situ without incurring artifacts due to the degassing that typically occurs with core recovery. A second generation DORISS instrument was developed at the Monterey Bay Aquarium Research Institute (MBARI) by engineering and science staff in 2005. The instrument is a plugin module for either of remotely operated vehicle (ROV) platforms at MBARI. DORISS has successfully performed in situ measurements on targets of scientific interest including high-temperature hydrothermal vent fluids, complex gas hydrates, and numerous other targets. Previously Raman techniques had been avoided to analyze sediment pore water geochemistry because of experience with the pore-waters strongly fluorescing. Simple experiments conducted with extracted pore-waters had previously demonstrated that fluorescence overwhelmed the relatively weak laser Raman signal. The in situ Raman pore water probe has worked around the fluorescence problem. The Raman pore water probe has been deployed a number of times at gas hydrate sites such as Hydrate Ridge, Barkley Canyon, and in the Santa Monica basin over the last two years. This paper will discuss the technique details and the exploration of expanding these same techniques into longer probes and looking at other difficult to obtain chemistries.
    01/2011;
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    ABSTRACT: With rising concern over the impacts of ocean acidification on marine life there is a need for greatly improved techniques for carrying out in situ experiments. These must be able to create a ΔpH of 0.3 to 0.5 by addition of CO2 for studies of natural ecosystems such as coral reefs, cold water corals, and other sensitive benthic habitats. Thus controlled CO2 perturbation experiments in the field rather than in aquaria are quickly becoming an essential ocean science tool. Free Air CO2 Enrichment (FACE) experiments have long been carried out on land to investigate the effects of elevated atmospheric CO2 levels on vegetation. However, only limited work on CO2 enrichment using quasi-open systems has yet been carried out in the ocean. Seawater CO2 has complex chemistry with significantly slow reaction kinetics, unlike land-air experiments where simple mixing is the major concern. Ocean experimental designs must to take these reaction rates into account. The net result of adding a small quantity of CO2 to seawater is to reduce the concentration of dissolved carbonate ion, and increase bicarbonate ion through the reaction: CO2 + H2O + CO3 2- → 2HCO3 - The reaction between CO2 and H2O is slow and is a complex function of temperature, pH, and TCO2. The reaction proceeds more rapidly at lower pH and higher temperatures. Marine animals in the natural ocean will typically experience only small and temporary shifts from environmental CO2 equilibrium. Valid perturbation experiments must try to expose an experimental region to a near stable lower pH condition, and avoid large and rapid pH variability to the extent possible. This paper describes the design, development and testing of an in situ pH perturbation experiment deployed on a subsea cable for control. The paper addresses the differences between the deep-sea and shallow water versions of the experiments and addresses the pH sensor developments that enable long deployments.
    01/2011;
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    ABSTRACT: The Monterey Bay Aquarium Research Institute (MBARI) has developed an AUV docking station for a 21-inch (54 cm) diameter AUV. The system was designed for operation with cabled undersea observatories in water depths up to 4 km deep and has been demonstrated in the open ocean, though at much shallower depths. The program demonstrated successful autonomous homing and docking, data downloads, uploading of new mission plans, battery recharging, and complete power cycling of the AUV. We describe the design, and at-sea tests.
    OCEANS 2007; 11/2007
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    ABSTRACT: The Monterey Bay Aquarium Research Institute (MBARI) has developed an autonomous seafloor mapping capability for deep ocean science applications. The MBARI Mapping AUV is a 0.53 m (21 in) diameter, 5.1 m (16.7 ft) long, Dorado-class vehicle designed to carry four mapping sonars. The primary sensor is a 200 kHz multibeam sonar producing swath bathymetry and sidescan. In addition, the vehicle carries 100 kHz and 410 kHz chirp sidescan sonars, and a 2-16 kHz sweep chirp subbottom profiler. Navigation and attitude data are obtained from an inertial navigation system (INS) incorporating a ring laser gyro and a 300 kHz Doppler velocity log (DVL). The vehicle also includes acoustic modem, ultra-short baseline navigation, and long-baseline navigation systems. The Mapping AUV is powered by 6 kWhr of Li-polymer batteries, providing a mission duration of 12 hours at a typical speed of 1.5 m/s. All components of the vehicle are rated to 6000 m depth, allowing MBARI to conduct high-resolution mapping of the deep-ocean seafloor. The sonar package can also be mounted on ROV Ventana, allowing surveys at altitudes less than 10 m at topographically challenging sites. The vehicle was assembled and underwent initial tests during 2004. During 2005 we have commenced science survey operations while completing the integration and testing of the complete suite of sensors and systems. MBARI is now using this capability in both autonomous and ROV-mounted surveys to observe the changing morphology of dynamic systems such as submarine canyons and active slumps, to map deep-water benthic habitats at resolutions comparable to ROV and submersible observations, to provide basemaps for ROV dives, and to provide high resolution bathymetry and subbottom profiles in support of seafloor observatory installations.
    AGU Spring Meeting Abstracts. 05/2005;
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    ABSTRACT: The Monterey Bay Aquarium Research Institute (MBARI) has developed an autonomous underwater vehicle (AUV) for deep ocean seafloor mapping. The MBARI Mapping AUV is a 21" diameter, torpedo-shaped Dorado class vehicle equipped with a 200 kHz multibeam sonar, 110 kHz and 410 kHz chirp sidescan sonars, and a 2-16 kHz sweep chirp sub bottom profiler. The multibeam sonar incorporates a circular receive array conformal to the vehicle hull, providing 1 degree × 1 degree beam resolution over a 150 degree swath. Navigation and attitude data are provided by an inertial navigation system integrating a laser ring gyro, accelerometers, and a 300 kHz Doppler velocity log (DVL). The vehicle is tracked during missions using an ultra-short baseline navigation system. The vehicle will also include acoustic modem and long-baseline navigation capabilities. A central cylindrical pressure housing contains all of the mapping sonar electronics. The main vehicle control and acoustic communications electronics are housed in a separate pressure housing in the vehicle tail section. Propulsion and steering are provided by a tailcone including an articulating propeller. Li-ion or Li-polymer battery packs allow for a 12 hour mission duration. The assembled package is rated to 6000 m depth. The mapping payload is also designed for ROV mounting, enabling low altitude (< 20 m) high precision missions in topographically challenging sites. The Mapping AUV has now been operated in both autonomous and ROV modes in and around the upper Monterey Canyon, successfully collecting high-resolution multibeam bathymetry and subbottom profile data. Near bottom surveys of the canyon axis achieve bathymetric coverage with a lateral resolution of 1 m and a vertical precision of 0.3 m. The subbottom profiler images subsurface structure to depths of 60 m in soft sediments.
    OCEANS, 2005. Proceedings of MTS/IEEE; 02/2005
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    ABSTRACT: The Monterey Bay Aquarium Research Institute (MBARI) is developing an autonomous seafloor mapping capability for deep ocean science applications. The MBARI Mapping AUV is a 0.53 m (21 in) diameter, 5.1 m (16.7 ft) long, Dorado-class vehicle designed to carry four mapping sonars. The primary sensor is a 200 kHz multibeam sonar producing swath bathymetry and sidescan. In addition, the vehicle carries 100 kHz and 410 kHz chirp sidescan sonars, and a 2-16 kHz sweep chirp subbottom profiler. Navigation and attitude data are obtained from an inertial navigation system (INS) incorporating a ring laser gyro and a 300 kHz Doppler velocity log (DVL). The vehicle also includes acoustic modem, ultra-short baseline navigation, and long-baseline navigation systems. A single cylindrical pressure housing contains all of the mapping sonar electronics, and the main vehicle control and acoustic communications electronics are housed in a separate glass ball. The Mapping AUV is powered by three 2 kWhr Li-polymer batteries, providing an expected mission duration of 12 hours at a typical speed of 1.5 m/s. The assembled package is rated to 6000 m depth, allowing MBARI to conduct high-resolution mapping of the deep-ocean seafloor. Initial at-sea testing commenced in May 2004 using the subbottom profiler and 100 kHz sidescan. The sonar package will also be mountable on ROV Ventana, allowing surveys at altitudes < 10 m at topographically challenging sites. The MBARI Seafloor Mapping team is now working towards integration of the multibeam sonar and towards achieving regular operations during 2005.
    OCEANS '04. MTTS/IEEE TECHNO-OCEAN '04; 12/2004
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    ABSTRACT: During the Spring and Summer of 2004, MBARI conducted subbottom profile surveys across the main, active channel of the upper Monterey Canyon and two northward trending sub-canyons that appear in swath bathymetry mapping to be mostly filled by recent sediments. Monterey Canyon is the dominant submarine physiographic feature of the Monterey Bay region, and serves as the primary conduit for sediment transport from the coast and shelf to the deep ocean seafloor. These surveys were conducted during the initial sea tests of the new MBARI Mapping Autonomous Underwater Vehicle (AUV). The data were collected using an Edgetech FS-AU 2-16 kHz sweep Chirp subbottom profiler operated on the AUV at vehicle depths up to 250 m. Navigation and attitude data derived from an inertial navigation system (INS) incorporating a ring laser gyro and a 300 kHz Doppler velocity log (DVL). Good subbottom data, with typical penetrations of 0.05 seconds, were collected along 140 km of profiles covering an area roughly 3.6 km east-west by 8 km north-south. The profiles clearly show that a single, stratigraphically uninterrupted deposit of sediments has in fact filled the northward sub-canyons. Profiles crossing the main channel also reveal remnants of previous sediment infill along the canyon walls, suggesting that the entire upper Monterey Canyon may have once been filled by sediments as much as 100 m thick.
    AGU Fall Meeting Abstracts. 12/2004;
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    ABSTRACT: The Monterey Bay Aquarium Research Institute (MBARI) is developing an autonomous seafloor mapping capability for deep ocean science applications. The MBARI Mapping AUV is a 0.53 m (21 in) diameter, 5.1 m (16.7 ft) long, Dorado-class vehicle designed to carry four mapping sonars. The primary sensor will be a 200 kHz multibeam sonar producing swath bathymetry and sidescan. In addition, the vehicle carries 100 kHz and 410 kHz chirp sidescan sonars, and a 2-16 kHz sweep chirp subbottom profiler. Navigation and attitude data are obtained from an inertial navigation system (INS) incorporating a ring laser gyro and a 300 kHz Doppler velocity log (DVL). The vehicle also includes acoustic modem, ultra-short baseline navigation, and long-baseline navigation systems. A single cylindrical pressure housing contains all of the mapping sonar electronics, and the main vehicle control and acoustic communications electronics are housed in a separate glass sphere. The Mapping AUV is powered by three 2 kWhr Li-polymer batteries, providing an expected mission duration of 12 hours at a typical speed of 1.5 m/s. The assembled package is rated to 6000 m depth, allowing MBARI to conduct high-resolution mapping of the deep-ocean seafloor. Initial at-sea testing commenced in May 2004 using the subbottom profiler and 100 kHz sidescan. The sonar package will also be mountable on ROV Ventana, allowing surveys at altitudes < 10 m at topographically challenging sites. The MBARI Seafloor Mapping team is now working towards integration of the multibeam sonar and towards achieving regular operations during 2005.
    AGU Fall Meeting Abstracts. 12/2004;
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    ABSTRACT: An Autonomous Underwater Vehicle designed for operation at high latitudes and under ice completed its first Arctic field tests from the USCGC Healy in fall of 2001. The ALTEX AUV has been under development since 1998, and is being created to provide: unprecedented endurance, ability to navigate at high latitudes, a depth rating of 1500 to 4500 meters depending on payload, and the capability to relay data through the ice to satellites via data buoys. The AUV's initial applications are focused on tracking the warm Atlantic Layer inflow - the primary source of seawater to the Arctic Ocean. Consequently the primary payloads are twin pumped CTD systems. Oxygen and nitrate sensors provide the ability to use NO as a tracer. An ice profiling sonar allows the AUV to estimate the ice thickness in real-time and is designed to generate high quality post-processed ice draft data comparable to that collected through the SCICEX program. The experiments in October aboard the USCGC Healy generated numerous water column and under-ice data sets. Traditional ship-based CTD operations were used to provide a comparison data set for AUV water column measurements. The post-processed ice draft results show reasonable ice profiles and have the potential, when combined with other science data collected, to shed some additional light on upper water column processes in ice-covered regions. Cruise results include: operating the AUV from the USCGC Healy in the ice pack, demonstrating inertial navigation system performance, obtaining oceanographic sections with the AUV, obtaining ice draft measurements with an AUV born sonar, and testing the data-buoy system. This work is supported by the National Science Foundation under grant NSF-OPP 9910290. The Packard Foundation and the Office of Naval Research have also provided support. The project was initiated under the National Ocean Partnership Program under contract N00014-98-1-0814.
    AGU Fall Meeting Abstracts. 11/2002; -1:0282.
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    ABSTRACT: The original Odyssey vehicle systems established a style of platform that has proven to be extremely versatile and useful for a variety of scientific missions. The Monterey Bay Aquarium Research Institute (MBARI) has carried forward the Odyssey design, now called Dorado. Dorado is a mid-sized vehicle in comparison to other AUV systems. Dorado vehicles are 0.5334 m (21") diameter, and are designed for deep water (4500 m) operation. The Dorado design improves upon the original Odyssey versatility by dividing the vehicle up into modular sections. Specific sections can then be built to carry out each type of mission. A Dorado vehicle can then consist of a nose section, one or several mission-specific midbodies, and a tail section. The main vehicle systems for propulsion, control, data handling, navigation, acoustic sub-systems, and most other standard functions are housed in the tail section. This paper introduces the history of the Dorado systems, and what has been accomplished to date. This paper further describes the various architectural concepts and operational results. Future planning is also discussed.
    OCEANS '02 MTS/IEEE; 11/2002
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    ABSTRACT: The authors' goal is to greatly increase access to the Arctic Ocean by creating and demonstrating a safe and economical platform capable of basin-scale surveys. Specifically, they are developing an autonomous underwater vehicle (AUV) for Arctic research with unprecedented endurance, and the capability to relay data through the Ice to satellites. They provide a means of monitoring changes taking place in the Arctic Ocean and investigate its impact on global climate changes. The vehicle will also be capable of seafloor surveys throughout the Arctic basin. Such a capability is of national and global interest and importance
    OCEANS, 2001. MTS/IEEE Conference and Exhibition; 02/2001