Shepard Meander Experiment information
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
operating voltage range
[acquire, sleep, peak]
|Data Management Goals|
Deep sea instrument notes: |
|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.
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:
|Daily summary of data sent to shore.|
|Currents, ADCP||RDI Sentinel ADCP 300 kHz||Continuous
10 seconds in-canyon
5 minutes outside canyon
|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
6-12 month duration
|Daily velocity data to shore|
|Mooring power system
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||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|