MBARI - Shepard Meander science experiment

Shepard Meander Experiment information

MBARI Ocean Observing System (MOOS) Specifications for science instruments and data management goals for interdisciplinary studies during the Shepard Meander Experiment. DRAFT March 2003
Sea Floor and Deep Water Column
Variables	Instruments, Packages, and Manufacturers	Operational Period Sampling Period Acquire Time	Power Source operating voltage range power consumption: [acquire, sleep, peak]	Data Management Goals
Deep sea instrument notes: This instrument list is based on the plan to deploy a single mooring with two benthic nodes, a BIN outside Monterey Canyon immediately west of Shepard Meander where the mooring will be anchored, and a RIN inside Monterey Canyon. Core measurements on each benthic node include temperature, salinity, currents (from current meters and upward-looking ADCP), particle scatter, and fluorescence. In-canyon temporal resolution of these core measurements should be higher because of the goal of describing short-term events within the canyon. From the in-canyon RIN, we will operate a water column profiler over the lower 300 m, or at least deploy a C/T string within this layer. From the BIN outside the canyon, we will operate a seismometer provided that the seafloor is sufficiently flat, as required by the instrument. At one or both nodes, we will deploy 1) a camera to image the seafloor, 2) a benthic respiration chamber with ISUS integrated (self-sustaining 2-3 day experiments 20-50 m from BIN), and 3) sediment traps in a) mid-water, b) near-bottom above the nepheloid layer (more than 300 m above bottom), and c) at the bottom. Canyon dynamics experience suggests the need to test instrument power consumption to get an accurate power budget (e.g. peak power specs not in manual). BIN/RIN design is being re-considered based on Canyon Dynamics experience. "Sensor-tree" design is being considered where complete instument package is simply swapped out every 6 months.
Temperature, conductivity, pressure fluorescence & particle scattering	Seabird SBE 16+ SEACAT with titanium housing and 8 MB flash memory. Pumping is considered necessary for good measurements. Fluorescence and particle scattering will be from two instruments (Seabird recommends WetLabs ECO BBD & FLD sensors). Note that a single instrument than can provide both fluorescence and scattering has been considered. The HS-2 would require serial to analog conversion - another gadget to break, and the ECO-FL-NTU does not have a deep-rated version. So the plan is to use two analog instruments with the SEACAT. Optical shutters should not be required.	Continuous 5 seconds in-canyon 5 minutes outside canyon 3 seconds with pump and pressure (p. 9 of manual)	Alkaline batteries with 12.2 amp-hours can support a deployment of about 1 year at 5 minute resolution with a pump but without a pressure sensor (very rough; see p. 12 of online manual). With pressure, power and sample time are increased by ~ 1/3, thus duration of deployment that batteries could support would be less. Lithium batteries are available, and we might want them because alkaline batteries can have problems in cold water. They have about 1/3 to 1/2 the output and duration of lithium batteries in cold water. Since we want to power a pump and 2 additional sensors from the SEACAT, this may be the better choice. The packs Seabird sells are $675 for 42 amp-hours. Also, if we power the fluorescence and scattering instrument(s) from the CTD, we must consider their power consumption: BBD: active 85 mA @ 7-15 VDC FLD: active 85 mA @ 7-15 VDC	Daily summary of data sent to shore.
Currents, ADCP	RDI Sentinel ADCP 300 kHz	Continuous 10 seconds in-canyon 5 minutes outside canyon 3.85 seconds	Internal battery for outside canyon, 6-12 month duration Mooring power system for the much higher sampling rate of in-canyon ADCP?	Daily mean profile of velocity and statistics to shore For high temporal resolution in-canyon; must consider data storage and transfer budgets.
Currents, fixed meter on benthic node	TBD in parallel with BIN re-design and ROV servicing considerations: MAVS current meter (NOBSKA) is probably best for scientific reasons as long as instrument protection (instrument cage) and related deployment concerns are addressed.	Continuous 5 seconds 0.04 seconds	Internal battery 6-12 month duration	Daily velocity data to shore
Nitrate	ISUS	Continuous 1 hour 30 seconds	Mooring power system 8-24 VDC Acquire: 7.5 W Sleep: less than 1 mA * 15 V = 15 mW Peak: 1 amp @ 15 V for less than 5 milliseconds.	Daily summary of hourly data to shore
Nutrients at a seep location?	Other nutrient measurements with MBARI Osmo- sampler/analyzer systems?	Continuous	Mooring power system ?	Daily statistics to shore
Sedimentation rate	Sediment traps from Prime Focus	Continuous operation	Battery power ?	Although a camera may be placed with the sediment traps, there are no plans for real-time data or imagery from sediment traps
Seismic activity	LP1-A? seismometer	Continuous	Internal battery ? month duration	Daily confirmation of continuing operation. Data recovered with instrument. Would simple daily summary statistics to shore be valuable?
Visible benthic condition	CoolPix camera in pressure housing?	1 picture / day	Mooring power system? ?	Daily picture transmitted to shore
Profile of [T, S, fluor, particle scattering] in lower 300 m	Deep profiling system	4 hours ? minutes per profile	? ?	Docking to permit data transfer?
Benthic respiration	MBARI benthic respiration chamber (BRC) with ISUS Possibly also a continuous method employing vertical velocity and oxygen measurements within bottom boundary layer; this would have to be on a separate apparatus 20-50 m away from the BIN to avoid hydrodynamic effects of the BIN	One-time deployment of 2-3 days for BRC, self contained (no mooring power or communications) Communications link only would be sought for the velocity/oxygen method.	TBD if velocity oxygen method is feasible in this experiment.	Daily summary of velocity oxygen data to shore if this method is feasible in this experiment