OS43B-0543 1340h
UK Ocean Bottom Instrumentation Consortium: a New Pool of Seafloor Geophysical Equipment
The UK Ocean Bottom Instrumentation Consortium (OBIC) comprises the University of Southampton, Durham University, and Imperial College (London). The consortium was set up to acquire and operate a fleet of ocean bottom geophysical instruments for both consortium members and the wider community. Potential external users of our instruments are invited to contact us at info@obs.ac.uk. Our current instrument pool consists of 28 instruments: 18 LC2000 two-component ocean bottom seismometers built by the Scripps Institution of Oceanography and 10 instruments built using existing housings and LC2000 electronics. The former are two-component instruments (hydrophone and 2 Hz vertical geophone) and the latter four-component instruments (hydrophone and three-axis 4.5 Hz geophone). The four-component instruments are also equipped with differential pressure gauges for broadband seismic recording. We have modified the two-component instruments to act as seafloor electric field detectors by adding electric field amplifiers and an additional chassis section accommodating AuCl electrodes mounted in two orthogonal 12-m dipoles. The seismic instruments have been tested successfully at sea in the Solent and in $\sim 1700$-m water depth offshore Ireland, and a prototype electric field instrument was tested in $\sim150$-m water depth in Lough Fyne, Scotland. Future plans include the development of an instrument capable of simultaneous seismic and electric field recording, and extending the bandwidth of seismic recording by the addition of broad-band seismometers and high-frequency data loggers to a subset of the instruments.
http://www.obs.ac.uk
OS43B-0544 1340h
Monitoring Local and Teleseismic Earthquakes Off--Shore San Diego(California) During an OBSIP Test Deployment
The Scripps OBS (Ocean Bottom Seismometer) team is one of three groups that provide instrumentation for the US National OBS Instrument Pool (OBSIP). The compact active source LC2000 instruments are being used successfully in numerous experiments, with excellent data quality and return rates. A set of five new passive seismic instruments was test--deployed from November 6th, 2003 through January 8th, 2004 in the San Diego Trough, about 1km below the sea surface, about 40km off--shore San Diego, California. These instruments are equipped with a Nanometrics Trillium 40s 3--component seismometer and a Cox--Webb differential pressure gauge. We recorded more than 30 teleseismic earthquakes suitable for a long-period surface wave study. The vertical--component seismometer recordings are of excellent quality and are often superior to those from similar sensors on land (Guralp CMG-40T). The signal--to--noise ratio on the DPGs depend strongly on the water depth and was expected to be low for the test deployment. Nevertheless, the December 22, 2003 San Simeon/ California earthquake was recorded with high fidelity and non--seismogenic signals are extremely coherent down to very long periods. We also recorded numerous local earthquakes. Many of these occurred off-shore and the OBSs were the closest stations by many tens of kilometers. For example, a magnitude 3.0 earthquake on the Coronado Banks Fault was recorded at station SOL in La Jolla at about 30km distance, with a signal-to-noise ratio too poor to pick the first arrival. The next closest stations were 60km and 80km away, while one of the OBSs was only 20km away. The co-deployment of DPGs allowed us to observe the first P arrival very clearly. We also recorded numerous events that were not recorded on land. About six months later, on June 15, 2004 the greater San Diego area was struck by a magnitude 5.2 earthquake on the San Clemente Fault, about 40km southwest of the OBS test deployment. Though no structural damage was reported, intensity 4 shaking occurred throughout the city, which prompted Amtrak and Sea World to shut down operations for inspections. These events are continous reminders that significant seismic hazard is caused by activity along the only poorly understood, off-shore faults in the California Borderland. Realtime seismic monitoring using cabled or moored seismic observatories is clearly needed.
OS43B-0545 1340h
An autonomous mid-column float designed to detect earthquakes
Two thirds of Earth's surface are virtually inaccessible to passive-source seismometry, save for expensive ocean-bottom seismometers or moored hydrophones. Here, we show our progress in the development of an independent hydro-acoustical recording device mounted on SOLO floats. Our instrument is able to maintain a constant water column depth below the sound channel and will surface only periodically for position determination and satellite data communication via the IRIDIUM protocol. A prototype has been built and taken out to the ocean for testing in November 2003 and September 2004. We have designed intelligent algorithms for the automatic identification and discrimination of seismic phases in the noisy ocean environment, combining continuous time-domain processing, spectrogram analysis, and custom-made wavelet methods. The lifespan and cost of the instrument are critically dependent on its ability to limit its power consumption by using a minimum amount of processing steps. Hence, we pay particular attention to the numerical implementation and efficiency of our algorithms. In addition to test analyses on data from ridge-tethered hydrophones we now show examples from data recently acquired in situ.
http://www.frederik.net
OS43B-0546 1340h
Time Domain Finite Difference Modeling of Abyssal T-Phases
A long standing problem in T-phase research is the disconnect between i) the steep grazing angles of sound propagation in the ocean from a source in the crust or upper mantle and ii) the shallow grazing angles required for sound traveling in the ocean sound channel. The characteristics of earthquakes, as revealed by T-phase observations, have the potential to provide important constraints on physical models of crustal processes under the oceans. We do not know, however, how to infer earthquake source mechanisms, magnitudes, or depth from T-phase observations because we do not know the physical mechanisms responsible for getting T-phase energy from the earthquake epicenter into the ocean sound channel. Scattering, "wave tunneling", interface waves (Stoneley, Scholte and Rayleigh waves), and shear wave resonances (modes) in the sediments have been proposed as possible mechanisms to convert the compressional and shear body waves from earthquakes into the low grazing angle paths necessary for propagation in the ocean sound channel. In order to quantitatively compare the various mechanisms we have constructed a numerical model of the ocean crust, seafloor and ocean sound channel that can be used to study full elastic wave propagation at 10Hz out to 30km in two dimensions.
http://msg.whoi.edu/msg.html
OS43B-0547 1340h
A Three-Dimensional Subseafloor Observatory Network for Cross-Hole, Hydrogeologic Experiments Established in the Northeast Pacific Ocean
The upper oceanic crust, composed mainly of basalt, comprises the largest aquifer on Earth. Global fluid fluxes through the upper oceanic crust are at least as large as the annual riverine flux to the ocean, and influence a diverse array of processes and properties, including the thermal state and evolution of oceanic plates; alteration of the lithosphere and the chemistry of flowing fluids; establishment and maintenance of vast subseafloor microbial ecosystems; and diagenetic, seismic, and magmatic activity along plate-boundary faults. Active experiments are needed in the oceanic crust to determine hydrogeologic properties at a crustal scale, and to quantify linkages between thermal, fluid, solute, and biological processes. The first expedition of the Integrated Ocean Drilling Program established two new subseafloor observatories within 3.5 Ma crust in the northeast Pacific Ocean, and replaced a previously-deployed observatory, in anticipation of planned cross-hole tests and related experiments. The new holes extend up to 320 m into basement and isolate distinct depth intervals. All of the new observatories are instrumented with autonomous temperature loggers, osmotic fluid samplers, and microbiological incubation substrate. Future experiments will include hydrogeologic tests to determine fluid transmission and storage properties, at cross-hole distances of 35 to 2200 m, tracer tests to quantify rates and modes of solute transport, and seismic experiments to elucidate relations between velocity and hydrogeologic anisotropy.
OS43B-0548 1340h
T-phase observed at deep seafloor boreholes
T-phases are seismic phases that have an acoustic propagation path in the ocean. They are mostly observed on hydrophones in the ocean sound channel or on shore based observatories. Although the acoustic energy of the T-phase is considered to be trapped in the SOFAR channel in order to travel long distances without attenuation, we have observed T-phases in the deep seafloor far below the SOFAR channel. It is not clear why T-phases should be observed in on the deep seafloor . To characterize the propagation of the T-phase in the deep ocean, we inspected long-term seismic records from two deep seafloor borehole seismometers in the Philippine Sea and the NW Pacific. These borehole seismometers (WP1 in the Philippine Sea, WP2 in the NW Pacific) are among the four ocean borehole seismic stations (JT1, JT2 near Japan Trench, WP1 and WP2) deployed during the Ocean Drilling Program legs 186 (JT1 and JT2), 191 (WP2), and 195 (WP1). The WP1 and WP2 stations employ broadband borehole seismometers cemented in the oceanic basement. The depths of the seafloor and the seismometer below the seafloor are 5.7km and 561m for WP1 and 5.5km and 460m for WP2 respectively. Despite their sensor locations at deep seafloor much below the SOFAR channel, we could see many of the seismic events accompanied the T-phases below 10Hz. Long-term observation from the seafloor boreholes enabled us to cover the whole regional seismicity. The distribution of seismic events observed with the T-phases and their T-phase amplitude compared with those of P/S phases, are useful to infer characteristics of acoustic wave propagation in the sea. The WP1 and the WP2 stations have been operational since March 2002 and October 2000 respectively. Over one year's worth of seismic data at each station were recovered by the ROV "Kaiko" (10km depth capable) until the loss of the vehicle in April 2003. Both stations are expected to record additional data for more than a year. We plan to recover them by a replacement vehicle "Kaiko 7K" in the near future.
OS43B-0549 1340h
Measurement Of Turbidity Current Associated With 2003 Tokach-Earthquake Using Cabled Seafloor Observatory
A turbidity current due to the _g2003 Tokachi-oki Earthquake (M8.0)_h was successfully measured by a cabled seafloor observatory which was deployed off Kushiro, Hokkaido in 1999. The cabled seafloor observatory consists of three-component ocean bottom seismometers, precise pressure sensors and a cable end station. The cable end station consists of an ADCP, electro-magnetic current meter, CTD, hydrophone and heat flow temperature probes. It was deployed at the landward slope of the southern Kuril Trench at a depth of 2630 m (Hirata et al., 2002, IEEE J. Oceanic Engineering). A direct reading 150 kHz Broadband ADCP is mounted with keeping up-looking direction by a gimbals assembly. The ADCP is set to measure the vertical current profiles up to 380 m every half hour. Bottom current is measured by electro-magnetic current meter with 1 Hz sampling speed. Temperature, salinity and pressure data are measured by CTD. All measurement data from the underwater instruments are transmitted to Yokohama Institute for_@Earth Science of JAMSTEC in real-time for using submarine electro-optical cable and NTT digital lines. A south-southwestward strong bottom current of over 100 cm/sec was observed as the turbidity current about two hours after the mainshock at 22:01 (UTC) on September 25, 2003 (Mikada et al., 2004, Tectonophysics (submitted)). It had been continued for about seventeen hours. The current speed has reached over 140cm/sec at about two hours later. The temperature increased in 0.5 deg C at maximum and salinity decreased in 0.2 PSU simultaneously. The thickness of the turbidity current becomes about 60 m. According to acoustic scattering signals, the suspended particles from bottom sediments reached up to100 m above the seafloor. A counter current was observed with 300 m in thick for approximately twelve hours after the turbidity current was over. These phenomena indicate that some submarine landslides or collapses of gas hydrate layers were caused by the earthquake. The temperature difference shows that the source of turbidity current was shallower than 1700 m.
OS43B-0550 1340h
10 Year Video Monitoring and its Implication to the Fluctuation Detected by Multi-disciplinary Observation on Deep Seafloor at Cold Seepage Site in Sagami Bay, Central Japan
As a part of multidisciplinary real-time observation at cold seepage site on deep seafloor which faces swarm earthquake area at a depth of 1175 m off Hatsushima Island in Sagami Bay, central Japan, video monitoring has been carried out for about 10 years by a cabled observatory. Through the monitoring, both outbreak event such as mudflows caused by earthquakes and long-term phenomena such as sedimentation on seafloor associated not only with mudflow but also with the fluctuation of the amount of suspended particles were observed, along with spawning of clams or other biological events. Some of these video images provide important information on the fluctuation observed by other sensors of the observatory, such as seasonal changes in sub-bottom temperature and intensity of gamma-ray, indicating that those fluctuations were primarily related to such environmental changes on seafloor as sedimentation. On the other hand, extracting meaningful events or phenomena from a huge amount of stored video images needs tremendous time and effort. Effective methodology of scene detection and indexing is necessary to be developed.
http://www.jamstec.go.jp/REMOTE/hatsushima/
OS43B-0551 1340h
Detecting Benthic Megafauna in Underwater Video
Remotely operated vehicles (ROVs) have revolutionized oceanographic research, supplementing traditional technologies of acoustics and trawling as tools which assess animal diversity, distribution and abundance. Video equipment deployed on ROVs enable quantitative video transects (QVTs) to be recorded from ocean habitats, providing high-resolution imagery on the scale of individual organisms and their associated habitat. Currently, the manual method employed by trained scientists analyzing QVTs is labor-intensive and costly, limiting the amount of data analyzed from ROV dives. An automated system for detecting organisms and identifying objects visible in video would address these concerns. Automated event detection (scene segmentation) is a step towards an automated analytical system for QVTs. In the work presented here, video frames are processed with a neuromorphic selective-attention algorithm. The candidate locations identified by the attention selection module are subject to a number of parameters. These parameters, combined with successful tracking over several frames, determine whether detected events are deemed "interesting" or "boring". "Interesting" events are marked in the video frames for subsequent identification and processing. As reported previously for mid-water QVTs, the system agrees with professional annotations 80% of the time. Poor contrast of small translucent animals in conjunction with the presence of debris ("marine snow") complicates automated event detection. While the visual characteristics of the seafloor (benthic) habitat are very different from the mid-water environment, the system yields a 92% correlation of detected animals on the seafloor compared with professional annotations. We present results detailing the comparison between a) automated detection and b) professional detection and classification, and we outline plans for future development of automated analysis.
http://www.mbari.org/AVED
OS43B-0552 1340h
Optical sensing for characterization of bubble plumes from methane seeps
Methane seeps are potentially a key contributor to atmospheric methane and to the global greenhouse gas budget. Improved estimates of methane flux from ocean floor seeps is required to understand the magnitude and characteristics of this contribution to the carbon cycle. % State of the art In steady, slow seeps a large portion of the gas is dissolved and oxidized before reaching the surface. However, in high-intensity methane seeps the bubble density, speed and size are such that a significant fraction of the gas can reach the atmosphere. Dissolved methane can be measured fairly reliably at the sea surface with traditional equilibration techniques. New types of in-situ chemical sensors can quantify dissolved methane deeper in the water column. Quantifying methane within the water column in the free gas phase (\emph{i.e.}, in the form of bubbles) remains a challenging problem. Current approaches rely either on indirect acoustic methods or direct collection of bubbles. Acoustic methods have the disadvantage of requiring extensive calibration, and can fail to distinguish the bubble signal from other sources of acoustic noise. Gas-capture techniques are mechanically complex, have a surface expression that introduces some noise, and can potentially alias episodic events. %how slow ? In both cases the fine scale structure such as herogeneity of the bubbling plume is lost. % Proposed We propose a vision-based system to detect and track bubble plumes. High speed optical imagery is propenables precise measurements of the motion of bubbles through a process involving identification of the individual bubbles (and rejection of other particles). Additional image processing steps are then used to estimate each bubble's volume and velocity. These are then integrated to produce an estimate of volumetric flux rate. This technique can also reveal fine scale variabilities in the spatial and temporal structure within the plume. %We discuss sensing configurations based on a stereo setup and based on a camera and a laser sheet. We are currently developing an imaging package that will be deployed on fixed moorings in parallel with an array of conventional chemical sensors. When deployed close to the ocean floor this system will also be able to recover cm-level bathymetry around the source of the plume. Preliminary results from a flume test with ground truth and a field test suggest that vision-based sensing can complement other sensing modalities.
OS43B-0553 1340h
In Situ Materials Study in Hot Hydrothermal Vent Fluid
We are developing methods and technology for {\it in situ} sampling and analysis of volatiles from hot hydrothermal vent fluids inside the mixing boundary. These fluids can reach temperatures of up to $400\deg$C and are known to be corrosive to most materials. While titanium has been the material of choice for contact with these fluids, we wanted to assess whether other materials, such as Hastelloy or nickel might be suitable for {\it in situ} sampling from hydrothermal vents. For the present study, small (1/16" o.d.) tubes of chemically pure titanium, Hastelloy C, and Nickel 200 were prepared, using 316 stainless steel as a control. These were placed in an assembly with other test items, and inserted into the hydrothermal vent Sully in the Main Endeavor Field on the Juan de Fuca Plate in June 2003 by the Jason II ROV operated from the R/V Thompson. The assembly was retrieved 46 days later after exposure to approximately $360\deg$C hydrothermal vent fluid at a depth of 2200 m. Inspection showed the stainless steel to be completely eroded away and nickel to be extensively corroded, however both the Hastelloy and titanium tubes were in excellent condition with the 0.030" i.d. passages in the tubes remaining open. Other test items included a miniature titanium filtered inlet fitting containing an 80 mesh titanium screen made of 0.004" (0.1 mm) chemically pure titanium wire, an Inconel washer and a sapphire ball. Apart from some discoloration, there appeared to be no significant degradation in these materials apart from signs of etching on the sapphire.
OS43B-0554 1340h
Mechatronic Integration of In-situ Chemical Sensors for Seafloor Observatory
There is a great demand for in-situ real-time chemical sensors in seafloor hydrothermal vent studies. Some strict requirements must be satisfied for any sensor-data logging system deployed in this extreme conditions: more than one chemical species along with temperature should be simultaneously measured and recorded; the acquired signals need to be amplified, regulated, and stored in the memory inside the pressure chamber of small size and low power consumption. During a recent Alvin/Atlantis cruise, newly developed chemical sensor and self-contained multi-channel data logging instruments were tested at the depth of 2500 m to quantify variations in vent fluid chemistry. The units were placed at different vent sites taking data at a rate of 5 second per-scan and recording up to 13 days. The multi-channel sensor-data logger mainly consists of two parts: one part is the sensor housing (40 cm x 5 cm diameter), which includes a hemisphere-shaped case with a hole-pattern that allows simultaneous sealing of multiple-sensor and electrodes, a Ti jacket is installed for sensor protection; the other is the circuit housing (38 cm x 8 cm diameter), which can be easily connected to the sensors through a underwater connector and cable. For viewing real time data inside the submersible hull, the unit makes use of ICL communication. In the circuit housing, MSP430 is used as CPU on the electronic board with very low energy consumption. All electronic components use chip encapsulation to make the electronic board much more compact, meanwhile a 4M interior storage is designed for the board. Currently 4 chemical sensors and 2 temperature sensors can be connected to the data logger for simultaneous data scanning with signal ranging from ?.25V to 1.25V at a tolerance of less than 1mV. 3 1.5V DC batteries are used for the circuit board and 3 high energy 3.6V batteries are used for the ICL system. Thus, sensor signals sampled in half an hour intervals permit the unit to operate for over a year. The total weight of the sensor-logger unit is less than 8 kg, so it can be easily taken by various submersibles to seafloor vent system.
OS43B-0555 1340h
A Deep-Sea Mass Spectrometer Instrument for Long-Term, In Situ Biogeochemical Monitoring
Mass spectrometry has been a major analytical tool for more than 100 years, but it has rarely been used to monitor the environment in situ. Furthermore, a deep-water instrument is even more challenging due to a lack of an effective membrane-introduction interface and an efficient high-vacuum system that will work remotely for long periods at very high pressure. Being able to solve these problems could greatly improve scientific work that requires long-term monitoring of the environment (geology, biology, oceanography). Traditional deep-water sampling methods usually involve the collection of water samples and delivery to a laboratory for analysis. This approach can result in degradation of sample quality over time and provide inaccurate results, but mostly, this approach limits a remote, in situ monitoring capability. In situ measurements by an underwater mass spectrometer can eliminate many problems intrinsic to traditional sampling methods and provide data with temporal resolutions that are difficult to obtain by other means. High sensitivity and the ability to simultaneously measure multiple species (e.g. hydrogen, helium, methane, oxygen, H2S or CO2) with the promise of isotopic resolution are its major features. We have developed an underwater mass spectrometer instrument for the in situ study of dissolved gases for six months to a year at up to 3000 m water depth, using battery power. This oceanographic instrument should eventually allow the measurement of dissolved gases and volatile organic compounds in a variety of ocean environments (cold seeps on the continental margins, deep-sea hydrothermal vents, submarine groundwater discharge and pollution in coastal areas).
OS43B-0556 1340h
Laser-induced Native Fluorescence Detection of Organic Molecules in Hydrothermal Vent Rocks
We have developed a Multi-channel Deep Ultraviolet Excitation (McDuve) fluorescence detector that has been deployed at several Pacific hydrothermal vent sites [1]. The in situ McDuve detector was able to detect organic molecules at the vent site on rock surfaces and in the water, the signatures being distinguishable one from the other. The McDuve fluorescence detector uses a 224.3 nm helium-silver hollow cathode laser to induce native fluorescence from a sample. Spectral separation is achieved with optical band-pass filters which are coupled to photomultiplier tubes (PMTs) for detection. Samples were recovered at the vent sites and returned from the expedition for bench-top analysis for correlation of the McDuve observations with standard analytical tools-GCMS and X-ray diffraction (for mineralogical ID), as well as with a bench-top version of the McDuve fluorescence detector. Here we report the corroborative results of the laboratory studies. Several preserved samples were subjected to 224.3 nm ultraviolet excitation under wet and dry conditions. Organic molecules were detected on the wet samples analyzed in the lab, corroborating the in situ McDuve data. The fluorescence emission wavelengths associated with the detected organic molecules suggest they are 3-5 ring polycyclic aromatic hydrocarbons [2,3]. The samples were also pyrolized at 500 °C to decompose any organic molecules present and subsequently reanalyzed. This McDuve analysis revealed a significant decrease in laser induced native fluorescence, a result consistent with the pyrolytic decomposition of the organic content of the rock samples. [1] Conrad, P.G., A.L. Lane, R. Bhartia, W. Hug, (March 2004) Optical Detection of Organic Chemical Biosignatures at Hydrothermal Vents 35th Lunar Plan. Sci. XXXV, 2055. [2] Karcher, W. (1985), Spectral Atlas of Polycyclic Aromatic Compounds, vol. I, Kluwer Academic Publishing Company, Dordrecht, Holland. [3] Bhartia, R., McDonald, G.D., Salas, E.C., Hug, W., Reid, R., Conrad, P.G., (2004) A Model to Differentiate Organic Compounds Based on UV Fluorescence Spectroscopy, Intl. J. Astrobiology, Suppl. 1, 115-116
OS43B-0557 1340h
First Attempts at Direct Raman Detection of the Oceanic Carbonate System
MBARI's Deep Ocean Raman {\it In-Situ} Spectrometer (DORISS) has been deployed on a number of scientific missions in the ocean, with the successful acquisition of spectra from a wide range of targets including minerals, gases, and gas hydrates. We are now exploring the future use of this instrument for the direct detection of aqueous species in natural waters, with a particular focus on the oceanic carbonate system. The ability to acquire {\it in-situ} data allowing a direct quantitative assessment of carbonate speciation would present a powerful new tool to the oceanographic community. Ocean scientists have long relied on indirect methods for determination of the individual carbonate system species in seawater through linking observations with apparent thermodynamic constants. However, direct Raman spectroscopic observation of HCO$_{3}$$^{-}$ and CO$_{3}$$^{2-}$ in solution is possible, although acquisition of spectra {\it in-situ} is difficult due to low concentrations in natural waters. We are attempting to address this problem using the DORISS instrument. The first objective is to determine the Raman scattering efficiency of HCO$_{3}$$^{-}$ and CO$_{3}$$^{2-}$, and thereby define the instrument requirements to enable direct determination of carbonate speciation in a $\sim$2mM TCO$_{2}$ solution. The second step is to increase the sensitivity of the system through improvements to the optical path and advanced post-processing techniques. To perform quantitative measurements using Raman spectroscopy a reference standard is required, where the relative scattering efficiency of the standard and target must be known (the Raman cross section ratio, $\sigma$$_{standard}$/ $\sigma$$_{target}$). We have chosen SO$_{4}$$^{2-}$ as the reference standard for seawater species, as the seawater SO$_{4}$$^{2-}$ signal is readily detected {\it in-situ} with short (sub 1 minute) spectral acquisition times. The scattering efficiencies of HCO$_{3}$$^{-}$ and CO$_{3}$$^{2-}$ with respect to SO$_{4}$$^{2-}$ were determined in the laboratory ($\sigma$$_{SO4}$/ $\sigma$$_{HCO3}$ = $\sim$4.2; $\sigma$$_{SO4}$/ $\sigma$$_{CO3}$ = $\sim$2.5). As both HCO$_{3}$$^{-}$ and CO$_{3}$$^{2-}$ are comparatively weak Raman scatterers, and the TCO$_{2}$ of seawater is ca. 10 times lower than the SO$_{4}$$^{2-}$ concentration, it is necessary to increase instrument sensitivity by a factor of 10-100 to enable rapid (sub 1 minute) {\it in-situ} detection of the seawater carbonate system. Current instrument sensitivity allows detection of $\sim$15mM HCO$_{3}$$^{-}$, or ca. 7 times the seawater concentration, using long ($\sim$30 minute) acquisition times and standard spectral processing software (GRAMS AI, ThermoGalactic). To increase sensitivity we have explored potential adaptations to DORISS and alternative methods of spectral processing. First, we tested a new sampling optic, the 532 nm PhAT system (Kaiser Optical Systems, Inc.). The current DORISS probe head utilizes a single optical fiber for signal collection, whereas the PhAT system utilizes a bundle of collection fibers, leading to a concomitant increase in instrument sensitivity to transparent and semi-transparent samples. Secondly, the application of partial least squares spectral processing (Eigenvector Research, Inc.) notably improves the Raman peak detection limit. The incorporation of the PhAT system, in addition to advanced spectral processing, could significantly increase the sensitivity of the DORISS instrument, enabling direct measurement of the seawater carbonate system.
OS43B-0558 1340h
{\it In Situ} Raman Spectra from the SeaCliff Hydrothermal Field (Gorda Ridge)
MBARI's {\it in situ} laser Raman spectrometer (DORISS - Deep Ocean Raman In Situ Spectrometer) was deployed at the SeaCliff Hydrothermal Field on the Gorda Ridge in July 2004. The first {\it in situ} Raman spectra of hydrothermal minerals and high-temperature fluid venting from the seafloor were obtained. These spectra are analyzed and compared to laboratory measurements of samples collected from the site. Laser Raman spectroscopy is a proven, powerful geochemical technique for analyzing the chemical composition and molecular structure of solids, liquids, and gases. During an expedition to Gorda Ridge on the R/V Western Flyer in July 2004, DORISS was deployed successfully by the ROV Tiburon at hydrothermal vents on the seafloor ($\sim$2700 m depth). Data were collected from hydrothermal fluids, chimney minerals (e.g., anhydrite and barite), and bacterial mats using two types of sampling optics: an immersion optic, and a non-contact optic. To collect spectra from opaque mineral samples, a precision underwater positioner (PUP) was used to position the DORISS probe head. PUP is a stand-alone, three degree-of-freedom positioner capable of moving the DORISS probe head with a precision of 0.1 mm (required by the small focal volume of the sampling optic). Raman spectra were collected of $\sim$300$\deg$ C vent fluids with both sampling optics. The Raman spectrum of seawater contains bands from the bending ($\sim$1640 cm$^{-1}$) and stretching (3000-3700 cm$^{-1}$) vibrational modes of the water molecule and a small peak from the S-O stretch of the sulfate ion ($\sim$981 cm$^{-1}$). Compared to $\sim$2$\deg$ C ambient seawater, vent fluid spectra show changes in the intensity ratios of the water bands due to the elevated temperature, and the sulfate peak is reduced. Additional components of hydrothermal fluid are present in such low concentrations that it is difficult to detect them with the current Raman system. The chimneys in the SeaCliff field are primarily anhydrite, and debris in the area also contains barite. We were able to obtain quality spectra of both anhydrite (primary peak at $\sim$1017 cm$^{-1}$) and barite (primary peak at $\sim$987 cm$^{-1}$). In addition, we were able to detect elemental sulfur which may have been produced by bacterial mats (peaks at $\sim$218 and 473 cm$^{-1}$).
http://www.mbari.org/raman
OS43B-0559 1340h
A New Replacement for the Deep Diving Submersible ALVIN: Initial Project Update and Concept
In August 2004, the National Science Foundation (NSF) funded the first phase of a 4-year project proposed by Woods Hole Oceanographic Institution (WHOI) to build a replacement submersible for the present human occupied vehicle (HOV) ALVIN operated by WHOI as part of the National Deep Submergence Facility. The design of the replacement HOV is the result of almost 10 years of deliberations among the scientific community and several studies including a recent 2004 National Research Council report on the "Future Needs of Deep Submergence Science". The over-riding design philosophy was to enhance capabilities and not to detract from the present ALVIN capabilities that have made it one of the premier research tools in oceanography. The replacement submersible will have a nominal depth capability of 6500 meters allowing access to over 99% of the world's ocean floor. The submersible is planned to have a sphere diameter of 2.1 m providing 27 cu. ft. of additional internal volume over the present ALVIN. A key improvement will be the viewport design with five viewports for a total 245 degree viewing area and with the forward three viewports having overlapping fields of view. This will provide an unprecedented view of the seafloor. The central pilot viewport is 7" in diameter with two forward 6" observer viewports and two lateral 5" observer viewports. The replacement vehicle will continue to operate with 1 pilot and 2 scientists inside the sphere. In order for the submersible to reach the greater depths will require increased descent and ascent rates. The new vehicle will operate with a variable water ballast system that can provide trim angles of up to +/-25 degrees to use on descent and ascent and will also enable the vehicle to stop in midwater to conduct experiments and sampling. Important design constraints are imposed by the capacity of the present ALVIN mother ship, Atlantis and the A-frame launch system. Due to these restrictions the replacement HOV will weigh 44,000 lbs compared to the present ALVIN 37,000 lbs and will only be slightly larger in overall dimension. A Lithium ion battery power plant will provide greater energy needed for the deep dives and greater endurance and speed. NSF has convened an oversight committee composed of scientists, US Navy personnel and deep submergence industry experts to oversee the various phases of the project. The scheduled completion date is 2008.
http://www.whoi.edu/home/index_alvinreplacement_pr.html
OS43B-0560 1340h
Hybrid Robotic Vehicle of Operations at 11,000 meters: Project Progress to Date
The National Science Foundation, Office of Naval Research and National Oceanic and Atmospheric Administration have teamed together to fund Woods Hole Oceanographic Institution for the design and construction of a novel robotic vehicle capable of operating in water depths of up to 11,000 meters. The vehicle, which combines the attributes of both an autonomous and tethered vehicle is appropriately termed a hybrid remotely operated vehicle or HROV. The operational paradigm for this vehicle will require that the system be cable of operating as either an autonomous or tethered system. In its autonomous mode, the HROV will be capable of gathering large area sonar and photographic survey data. Once the mapping information has been analyzed aboard the support vessel and specific areas of interest identified, the vehicle is converted to operate as a tethered vehicle. The tether is based on US Navy work with small diameter fiber optic micro-cable that will be adapted to this application. In both modes of operation, the vehicle will be battery powered. The fiber tether only provides a real-time data link between the vehicle and operators for the purpose of conducting highly interactive operations such as manipulation and sampling. Because of the extreme pressures at 11,000 meters and a desire to limit the size and cost of the vehicle, use of new materials and techniques will be required such as alumina ceramics for pressure cases and flotation and light emitting diodes for illumination. Funding for this project began in 2003 and many of the higher risk elements of the project are well underway. Trial deployment of the vehicle to Challenger Deep of the Marianas Trench is expected in late 2006.
OS43B-0561 1340h
A Universal Docking Mechanism for Multiple AUVs With Differing Geometries
One of the fundamental technologies associated with observatories is the concept of a docked autonomous underwater vehicle (AUV) at a node capable of power and data transfer. The evolution of AUVs over the last few years has made it obvious that there will be a number of such vehicles and that these will fulfill different scientific needs and applications. Different scientific applications may require an AUV to work near the surface, in the mid-water column or near bottom. Sensors on the vehicle also dictate different vehicle characteristics. For example, the requirements for slow speed control or hovering near bottom versus long endurance and speed in the mid-water column yield radically different designs. These design characteristics and requirements have led to the development of a diverse set of AUVs such as the Remus AUV (small, torpedo shaped), the Odyssey AUV (larger, torpedo shaped),the ABE AUV (triple hulled, hover capable), and the Seabed AUV (double hulled, hover capable). While considerable effort and thinking has gone into the design of docking systems, each of these systems is specific to the AUV itself, and we are unaware of any published work that provides a common standard docking mechanism that can be utilized by all these assets. In this presentation we highlight our work in engineering a small docking mechanism that is capable of handling multiple vehicles with differing geometries within the same dock. Thus our docking mechanism can easily accomodate a small REMUS style torpedo shaped AUV as well as a larger multi-hulled ABE style AUV without modification on the same dock. In addition this dock is equally capable of being installed on the ocean floor, or anywhere within the water column. We present this system within the context of measures of efficiency that allow us to formulate the requirements for docking and evaluate our system as well as other existing systems or those that may be proposed in the future.
OS43B-0562 1340h
Development of the MBARI Mapping AUV
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.
OS43B-0563 1340h
A Subbottom Profiler Survey of the Upper Monterey Canyon Using the MBARI Mapping AUV
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.
OS43B-0564 1340h
An Ice-Tethered Profiler: Initial results and role in a future Arctic network of Ice-Based Observatories
On August 19, 2004 a prototype Ice-Tethered Profiler (ITP) was deployed from a 4-m-thick ice floe near 77 N, 141 W within the Canada Basin of the Arctic Ocean. The ITP was conceived as a polar complement to the international ARGO program of drifting floats that is returning temperature and salinity profile data from the temperate oceans. Having physical dimensions similar to a profiling float, the ITP, deployed on a weighted, plastic-jacketed wire rope suspended below an ice floe, uses a traction drive system to move up and down the wire on a pre-programmed sampling schedule. At the completion of each one-way profile, raw 1-Hz Conductivity - Temperature - Depth (CTD) data and engineering information are telemetered in turn from the underwater profiling module to the surface unit via the wire tether using an inductive modem, and from the surface unit to a shoreside data server with over an Iridium satellite telephone link. Status messages from the surface controller (including position information) are also telemetered on an independent schedule. The first ITP was programmed with an accelerated sampling plan of 6 one-way profiles per day between 10 and 750 m depth. Profiling speeds of 26-28 cm/s are being routinely achieved with profile-averaged motor current from the 10.8 V battery supply ranging between 100 and 250 mA. Larger motor currents are observed at times of fast ice floe motion (approaching 25 cm/s on occasion) when we presume that drag on the Profiler and wire are increased. These figures are consistent with our instrument design goal of a three-year lifetime with average sampling rate of 1-2 profiles per day. The CTD profile data so far obtained document interesting spatial variations in the major water masses of the Beaufort Gyre including the low-salinity surface mixed layer, the complex forming the Pacific Halocline Waters characterized by multiple temperature extrema between 40 and 180 m depth indicative of the Alaska Coastal Water, the Summer and Winter Bering Strait Waters and winter shelf waters emanating from Barrow and possibly Herald Canyons, and the temperature maximum around 350 m depth characterizing the Atlantic Water. Additionally, the 1 Hz CTD data resolve well the thermohaline staircase stratification above the Atlantic Layer thought to be caused by double diffusion and the "nested" intrusive structures that incise the Atlantic Water. In addition to results from this prototype instrument, a concept for future deployments of ITP's within a network of Ice-Based Observatories will also be presented.
http://www.whoi.edu/itp/
OS43B-0565 1340h
An Array of Ice-Based Observatories for Arctic Studies
The Arctic Ocean's role in global climate - while now widely appreciated - remains poorly understood. Lack of information about key processes within the oceanic, cryospheric, biologic, atmospheric and geologic disciplines will continue to impede physical understanding, model validation, and climate prediction until a practical observing system is designed and implemented. Requirements, challenges and recommendations for Ice-Based Observatories (IBO?s) for the Arctic Ocean were formulated by workshop participants of an international workshop entitled "Arctic Observing Based on Ice-Tethered Platforms" held at the Woods Hole Oceanographic Institution in Woods Hole, Massachusetts, USA, June 28-30, 2004. The principal conclusion from the workshop was that practical, cost-effective and proven IBO designs presently exist, can be readily extended to provide interdisciplinary observations, and should be implemented expeditiously as part of a coordinated Arctic observing system. Ice-based instrument systems are a proven means of acquiring unattended high quality air, ice, and ocean data from the central Arctic during all seasons. Arctic Change is ongoing and measurements need to begin now. An array of approximately 25-30 IBO units maintained throughout the Arctic Ocean is envisioned to observe the annual and interannual variations of the polar atmosphere-ice-ocean environment. An international body will be required to coordinate the various national programs (eliminate overlap, insure no data holes) and insure compatibility of data and their widespread distribution. A long-term, internationally coordinated logistics plan should be implemented as an essential complement to scientific and technical plans for an IBO array. The 25 years of IABP drift trajectories, existing data climatologies and available numerical simulations should be exploited to derive insight to optimal array design, deployment strategies, sampling intervals, and expected performance of an IBO array. IBO designs should provide accommodation for novel sensors, tomographic receivers, and communication and navigation capabilities for free vehicles. Emerging technologies for Arctic observation should be developed within the framework of an integrated Arctic observing system.
OS43B-0566 1340h
Real-time Internet Data Collection for ORION Platforms
A range of telecommunications technologies are available to provide ORION platforms with data collection and command and control functions. Options range from cell phones, cables, and point-to-point microwave links for near-shore platforms to C-band and Ku-band satellite systems for deep-ocean platforms. We outline the characteristics and costs of representative communications systems. HiSeasNet, which provides or will provide continuous Internet connectivity to most of the larger UNOLS ships, serves as a prototype for ORION's deep-ocean observatories. We describe the architecture of this system and its middleware component, ROADNet (Real-time Observatories, Applications, and Data management Network). ROADNet provides the infrastructure for multiple sensors (e.g. cameras, meteorology, seismic, geodetic, chemical), data buffering, data sharing, data grids, and information integration that supports the multidisciplinary collection of measurements on distributed sensor platforms.
http://www.hiseasnet.net
OS43B-0567 1340h
Implementation of Distributed Services for a Deep Sea Moored Instrument Network
The Monterey Ocean Observing System (MOOS) is a moored observatory network consisting of interconnected instrument nodes on the sea surface, midwater, and deep sea floor. We describe Software Infrastructure and Applications for MOOS ("SIAM"), which implement the management, control, and data acquisition infrastructure for the moored observatory. Links in the MOOS network include fiber-optic and 10-BaseT copper connections between the at-sea nodes. A Globalstar satellite transceiver or 900 MHz Freewave terrestrial line-of-sight RF modem provides the link to shore. All of these links support Internet protocols, providing TCP/IP connectivity throughout a system that extends from shore to sensor nodes at the air-sea interface, through the oceanic water column to a benthic network of sensor nodes extending across the deep sea floor. Exploiting this TCP/IP infrastructure as well as capabilities provided by MBARI's MOOS mooring controller, we use powerful Internet software technologies to implement a distributed management, control and data acquisition system for the moored observatory. The system design meets the demanding functional requirements specified for MOOS. Nodes and their instruments are represented by Java RMI "services" having well defined software interfaces. Clients anywhere on the network can interact with any node or instrument through its corresponding service. A client may be on the same node as the service, may be on another node, or may reside on shore. Clients may be human, e.g. when a scientist on shore accesses a deployed instrument in real-time through a user interface. Clients may also be software components that interact autonomously with instruments and nodes, e.g. for purposes such as system resource management or autonomous detection and response to scientifically interesting events. All electrical power to the moored network is provided by solar and wind energy, and the RF shore-to-mooring links are intermittent and relatively low-bandwidth connections. Thus power and wireless bandwidth are limited resources that constrain our choice of service technologies and wireless access strategy. We describe and evaluate system performance in light of actual deployment of observatory elements in Monterey Bay, and discuss how the system can be developed further. We also consider management and control strategies for the cable-to-shore observatory known as MARS ("Monterey Accelerated Research System"). The MARS cable will provide high power and continuous high-bandwidth connectivity between seafloor instrument nodes and shore, thus removing key limitations of the moored observatory. Moreover MARS functional requirements may differ significantly from MOOS requirements. In light of these differences, we discuss how elements of our MOOS moored observatory architecture might be adapted to MARS.
OS43B-0568 1340h
Deployment of a Deep-Water, Acoustically-Linked, Moored Buoy Observatory on the Nootka Fault, off Vancouver Island
We have developed an acoustically-linked moored buoy system that uses high-speed acoustic modems for two-way communication between instruments on the seafloor, or in the water column, and a surface buoy. An Iridium satellite link on the buoy telemeters data to shore several times a day and can be used in conjunction with the two-way acoustic link to send commands to instruments at the observatory. This system is ideally suited for a variety of applications where data telemetry requirements are relatively modest, but real-time or near real-time data are required. A conventional discus buoy (2.7m diameter) is equipped with dual Iridium transceivers, two acoustic modems, a Linux-based system controller, and a solar power system with a three-month alkaline battery backup. Up to 15 remote nodes on the mooring or on the seafloor can be polled several times a day and the data passed back to shore via the Iridium satellite link. Total demonstrated data throughput has been ~1 Mbyte/day and can be much higher. An initial 2 month test deployment in Nov. 2003 off the U.S. east coast verified the operation of the acoustic and Iridium data links, as well as the control, power and mooring systems. Acoustic data rates of up to 5300 b/s have been achieved in 2700m of water at slant ranges of just under 3 km using modest transmit power ($<$10W). The Iridium connection has been used to remotely reconfigure various aspects of the data collection system as well as transfer large quantities of data. In May 2004 this system was deployed for one year at a seep site off Vancouver Island where the Nootka fault crosses the toe of the accretionary prism in order to monitor fluid expulsion along the fault, and to examine the links between seismic deformation and episodic flow. The Nootka observatory is equipped with a suite of meteorological sensors on the buoy, an in-line current meter on the mooring, an Ocean Bottom Seismometer, and two additional seafloor nodes, one of which is equipped with sensors for monitoring the seep site, including temperature, fluid resistivity, heat flow, and an optical flow meter. The data from these sensors are collected on shore automatically and displayed on a web page in near real time (http://fathom2.whoi.edu/). Initial results from this prototype observatory will be shown based on data telemetered to shore in near-real time.
http://fathom2.whoi.edu
OS43B-0569 1340h
WireWalker Wave Powered Profiling Platform
The WireWalker is an inexpensive wave-powered vertical profiler. It consists of a wire and float system with a vertically traveling instrument platform. Wave action moves the wire, allowing the platform to ratchet down and float up. The platform profiles quickly enough to observe diel and higher frequencies, up to and including internal wave observation. The system is designed for flexibility of use. Deployments can be made for either drifting or moored applications and it is small enough to be handled without heavy equipment or large vessels. The platform is generalized to carry a variety of instruments. The WireWalker has been deployed in both coastal and open ocean environments in various environmental situations and proven robust. Successful deployments were made both tethered and free floating in the open ocean. Deployment vessels have included the R/P FLIP and the NOAA ship Ka' Imimoana. Current projects with the system aim at expanding its range in distance and time. Communications systems and on-board power generation are also under development.
OS43B-0570 1340h
Evolution of Fronts in the Mid-Atlantic Bight: What Exit on the Ocean Highway Off New Jersey?
The New Jersey Shelf Observing System (NJSOS), a regional ocean observatory, is currently deployed in the New York Bight as part of the larger NorthEast Observing System (NEOS). Remote sensing data from an international constellation of satellites and a CODAR-type HF radar surface current array provide continuous synoptic surface maps over the shelf. For 2002 and 2003, full resolution NOAA AVHRR (~1 km) and SeaWiFS (~1.1 km, 4th reprocessing) imagery of the New York Bight region were averaged into time composites from 4 to 90 days. Long-range current maps were similarly averaged to match the scales of the satellite composites. Long-term averages of surface currents in the MAB indicate two transport pathways to the outer shelf. One originates near the mouth of New York Harbor and moves out along the Hudson Canyon. The second, originating upshelf, enters the field from the north and moves slowly toward the south. The flow along the Hudson Canyon is an alternative pathway that is a more direct transport to the shelf/slope region of the MAB. The sea surface temperature over the Hudson Canyon shows similar links to the canyon topography with cold inner shelf water following the 50 m isobath, and warmer water offshore. Similarly there is a lower chlorophyll concentration over the canyon than in the surrounding water. Although the temperature signature in the New York Bight is strongest in the winter, CODAR and surface chlorophyll measurements indicate the Hudson Canyon front occurs year round and can have significant influences on cross-shelf transport of organic material.
http://marine.rutgers.edu/cool
OS43B-0571 1340h
The VIMS CBOS Observing System Buoy, an Initial Scientific Analysis
The Virginia Institute of Marine Science (VIMS) has recently deployed a data buoy at Gloucester Point, York River, Virginia as part of the Chesapeake Bay Observing System (CBOS). The data streams collected by the buoy and its associated sensors are wind speed and direction, incoming solar radiation, air temperature, water temperature, salinity, turbidity, fluorescence, and dissolved oxygen. In addition, water velocities throughout the water column are recorded every 5 minutes and wave statistics including directional wave spectra are calculated every hour from an upward looking RD Instruments Acoustic Doppler Current Profiler (ADCP) in 8 meters of water in conjunction with the data buoy. All data are collected in real time and are available to scientists with a 15 minute to 1 hour time lag. These data are used in conjunction with other long tem data sets in the York River and lower Chesapeake Bay such as the Chesapeake Bay National Estuarine Research Reserve (CBNERR) sites' water quality data in the York River and USGS stream flow data to investigate several questions of scientific interest. One of these questions is the observed reverse salinity gradient in the York River during spring flood tides. It was previously thought that this was caused by a temporal mismatch in the phase of flood tide between the lower Chesapeake Bay and the mouth of the York River subestuary only during spring tides when the currents are strongest and the tidal range is large. In 2004, however, this effect can be seen during both spring and neap tides on several occasions in the spring and summer. This phenomenon and others are evaluated in the context of the VIMS observing system buoy and the initial data collected from the buoy are also evaluated in terms of instrument accuracy, ease of data retrieval, and possible uses for this information.
http://www.vims.edu/~lbrass/
OS43B-0572 1340h
Bodega Ocean Observing Node (BOON).
The Bodega Ocean Observing Node (BOON) is comprised of radar mapping of surface currents, a moored current profiler, and shoreline oceanographic and meteorological observations. Ongoing shoreline data on temperature and salinity date back to 1955, with continuous records of sealevel, wind, meteorology, and chlorophyll fluorescence starting more recently. Radar observations started in 2001 with deployment of two CODAR antennae. Together with a third CODAR unit deployed in 2002, these provide coverage from Pt Reyes north to the CODE line. Real-time ADCP data from the mooring started in late 2004. Plans include nearshore wave data, CTD/fluorescence data from the mooring, and deployment of a nutrient sensor at the shoreline. This coastal ocean observing node is part of the state-funded COCMP-NC program and the CeNCOOS regional association for central and northern California. Ancillary regional data are available on offshore winds (NDBC buoys), offshore waves (CDIP buoy), river flow, and satellite observations. The value of this suite of measurements is built on (1) detailed understanding of circulation, derived from WEST, CODE, and other prior studies of this region, including mesoscale atmosphere and ocean modeling, (2) active integration of circulation patterns in ongoing studies of planktonic and benthic ecology, and (3) direct interaction with local, state and federal agencies with interest in this region. To-date, the ongoing data series have shown potential for improved understanding and monitoring of fishery populations such as salmon and crab, as well as water quality concerns including oil spills and toxic pollutants. Through an active involvement in local studies and environmental management issues, BOON seeks to develop alternatives to supply-side thinking in the design of coastal ocean observing systems. BOON is based at the Bodega Marine Laboratory and thus provides invaluable support for academic study of more fundamental questions, such as carbon budgets in coastal upwelling systems and the importance of the spatial structure of coastal pelagic habitat.
http://www.bml.ucdavis.edu/envdata/
OS43B-0573 1340h
The Monterey Ocean Observing System Development Program
The Monterey Bay Aquarium Research Institute (MBARI) has a major development program underway to design, build, test and apply technology suitable to deep ocean observatories. The Monterey Ocean Observing System (MOOS) program is designed to form a large-scale instrument network that provides generic interfaces, intelligent instrument support, data archiving and near-real-time interaction for observatory experiments. The MOOS mooring system is designed as a portable surface mooring based seafloor observatory that provides data and power connections to both seafloor and ocean surface instruments through a specialty anchor cable. The surface mooring collects solar and wind energy for powering instruments and transmits data to shore-side researchers using a satellite communications modem. The use of a high modulus anchor cable to reach seafloor instrument networks is a high-risk development effort that is critical for the overall success of the portable observatory concept. An aggressive field test program off the California coast is underway to improve anchor cable constructions as well as end-to-end test overall system design. The overall MOOS observatory systems view is presented and the results of our field tests completed to date are summarized.
OS43B-0574 1340h
Geology of Smooth Ridge: MARS-IODP Cabled Observatory Site
We document the geologic environment of Smooth Ridge, off shore Central California, where the deep-water node associated with the MARS (Monterey Accelerated Research Site) scientific research cable is to be deployed. The MARS cable will provide internet connections and electric power at a node in 890 m of water in support of scientific observatory development and experiments. IODP boreholes are proposed which will be connected to the MARS cable. The deeply incised channels of Monterey and Soquel Canyons flank Smooth Ridge to the SW and NE and the San Gregorio faults marks its NW and upslope boundary. However, the top of Smooth Ridge, as its name implies, only has subdued bathymetric features. These include a subtle downslope channel and one distinct slump scar. A patch of acoustically reflective seafloor on the west side of the ridge, over 5 km from the MARS site, is associated with the only known large-scale biological community on the crest of Smooth Ridge. A reflection seismic survey conducted in 2003 with a high-resolution electrical sparker source reveals the stratigraphy of the Smooth Ridge in unprecedented detail. In conjunction with previously collected widely-spaced multichannnel seismic data, observations and samples obtained using remotely-operated vehicle (ROV) dives, and piston cores, this new survey reveals the erosional and depositional history of Smooth Ridge. The continuity of seismic reflections indicates nearly undisturbed deposition occurred until at least the mid-Miocene. Since that time, and especially since the upper Pliocene, the record is marked by unconformities and infill due to shifting channels, large slumps and landslides, and sediment waves. Several crossing seismic lines provide a quasi-three-dimensional view of a distinct slump scar's structure, and reveal a history of multiple headwall failures. Other subsurface structures, including a much larger, and older, slump feature, have no bathymetric expression at all. 14C dated piston cores, and ROV observations and sampling reveal that sediments have not been accumulating in the Holocene. Exposure of Plio-Pleistocene strata on the surface of Smooth Ridge in water depths of less than 1 km indicates that this is an area of active seafloor erosion. Measurements of sulfate gradients in piston cores indicate sulfate depletion occurs between 3 to 5 m below the seafloor, which is unusually shallow for continental margin sediments and suggests enhanced biogeochemical/microbiological activity occurs in the subsurface under Smooth Ridge.