Updates from the R/V Wecoma:
Sunday 9/10
Thursday 9/14
Sunday 9/17

Description of Research
The LBNL program aboard R/V WECOMA seeks to understand the ocean biological carbon cycle with new robotic explorers. 

CO₂ AND THE OCEAN BIOLOGICAL CARBON PUMP

The biological systems within the ocean play a key role in the global cycle of carbon and thus in regulation of atmospheric CO₂.  Every marine plant is eaten once per week (on average) by the zooplankton and fish. Sinking detritus from 'dinner leavings' and fecal matter transports a huge about of carbon downwards each year. The rate is ~10 Pg C/yr (1 Pg = 10^15 g). This carbon redistribution in the sea, commonly called the 'biological carbon pump', is very fast, highly variable, and very hard to observe from ships.

Simulations running on powerful computers are the only way to predict the impacts of human activities on climate and ecosystems.  A lack of good observations of the ocean biological carbon pump means that it is not possible to predict with confidence the consequences of anthropogenic CO₂ induced warming and ocean acidification on the life processes that sequester carbon in the sea.

Aboard WECOMA, we (Jim Bishop and Todd Wood) are testing new robotic observing technology that will overcome observing limitations in two ways.

CARBON FLUX EXPLORER

First, we had hoped to launch for the first time a totally free and autonomous vehicle called the Carbon Flux Explorer. The CFE is designed to follow the daily variations of carbon sedimentation for seasons at various depths in the ocean and to report findings via real time satellite link to shore. The CFE vehicle is based on the ocean profiling Sounding Oceanographic Lagrangian Explorer developed at Scripps Institution of Oceanography by Russ Davis and the engineers of the Instrument Development Group. Thousands of ocean profiling floats like SOLO are now deployed globally to observe ocean temperature and salinity as part of an international project called AGRO. SIO has modified the well proven SOLO so that it can carry our carbon flux measuring instrument.

Our instrument is designed to passively observe the sedimentation of sinking carbon particles. It can measure the variations of organic and inorganic carbon sedimentation twice per hour. It's components include an imaging system, external and internal lights, computer, and controller and about 2.5 kgs (5 lbs) of lithium batteries. All parts are housed in a pressure case. It must survive punishing waves, extremes of temperature (40C to -2C), and pressures as high as 100 atmospheres (1500 psi), and do this is in salt water.

The SOLO and our flux instrument (the payload of the SOLO) were ready for first launch into the ocean on Sept 15th. There was a long check list of items prior to launch and each one must pass in order to proceed to the next step.

Our instrument and SOLO were operational, mission commands programmed; however, at step #23 of the launch sequence (think space shuttle count down) we lost communication with the SOLO's computer.  Attempts to revive it failed. The CFE will not see the ocean until engineers at SIO understand the cause of the failure. Failures are an expected result of developing ocean instruments.

BUOY TESTING:

We have a second program to support the CFE development.  We have twin carbon flux measuring instruments operating at 250 m below a surface BUOY. These instruments are in all ways identical to that of the Explorer. Both instruments should 'get' the same result and thus give us confidence that the technology is robust. These twin systems are also outfitted to collect samples. We will analyze these samples for calibration purposes. The aim is to gain days of experience with the instruments under water. We know where the BUOY is since it gives us GPS (global positioning system) coordinates every half hour.  By the time WECOMA docks Sept 22nd, we expect to have ~10 days of data to analyze ashore.

Sunday, September 17th 1300

The Carbon Flux Explorer looks like it will not be deployed during this expedition. The Explorer is two parts: autonomous profiling vehicle and our instrument.  Our instrument which measures carbon sedimentation (the pay load on the vehicle) is working well, the profiling float which would transport it to depth no longer will no longer talk with our computer and thus cannot be programmed. We have no idea why the failure occurred.  Engineers at Scripps Institution of Oceanography, who developed the profiling float, will figure out why the failure happened.

Todd Wood is working with the Explorer's instrument to see if we can improve it's performance. An autonomous instrument can operate as long as there is power from the batteries. Every 3 seconds of time we shave from the operating cycle extends the mission by 1%. There are still many areas for improvement.

On Sept 16 at 0530 we deployed our heavier than water package with twin carbon sedimentation recording instruments for a second time. This package dangles at 250 m below a surface float. Last deployment was for only 30 hours and only one of our twin instruments was in it's pressure housing. This time both instruments are installed and each system will additionally collect samples of sinking particles as it operates.  These instruments are identical to the one carried by the Carbon Flux Explorer; thus we'll have useful experience with the system under water. The more days of experience with the instrument at depth the better.

We found the cause of the vacuum leak that had troubled us several days ago. While deployed at depth for 30 hours about 3 cc's of seawater had leaked into the pressure case of the troublesome instrument. The location of the water pointed to the cause of the trouble.  One of the main o-rings sealing the case was flattened.  We replaced the oring and the leak problem was cured.

We discovered a new gremlin with the electronics.  Allowing the lithium batteries that power our system to communicate with seawater through metal fittings of the pressure case is bad. The 30 hour test which started Sept 14th showed that we were doing just this. The titanium pressure case which houses the instrument was coated with a white powder (I suspect Titanium oxide).

It was not until late on Sept 15th that we found the other failure that allowed the electrical circuit to be completed. A conical conmonent of a light had been machined with razor sharp edges. This part had cut into the rubber instuation of the wire supplying power to the light. There was a curious yellow / gold substance plated on the stainless steel parts of the light. The color appears to have come from orange electrical tape attached to the stainless steel near by; the tape has a burned appearance. 

All of this happened in seawater. The electrochemistry of this escapes me. We have the parts for further analysis at LBNL.

The buoy system deployment planned for 2300 on the 15th was delayed by seven hours to allow us to repair and address the causes of the electrical issues and to file and polish smooth the sharp metal edges that caused the problem. Todd Wood and I finally went to bed at 3 am on the 16th. 

We got up two hours later and proceeded with the equipment launch.  The weather had changed.  The captain almost canceled the deployment due to concerns about operating the ship's crane in the 20-25 winds and 10-15 foot seas we were experiencing that morning. The good news is that the deployment went perfectly and safely.

One casualty... I left a camera on a workbench on the fantail (after deck/stern deck).  As the ship was turning into the wind and seas to get ready for the Buoy system deployment, it took a large roll and about 1 foot of seawater rushed over the deck. The camera flew off of the table  into the rushing water, but stayed on board. I immediately removed the battery and rinsed it thoroughly with distilled water and it's in the process of drying out. It may just survive. This experience is yet again reinforcement of the fact that although we as humans can feel perfectly adapted to ship's motion, inanimate objects follow the rules of physics.

As of this writing, the Buoy system instruments have been deployed now for 32 hours.  (recovery is scheduled tomorrow at 6 am). The drift track is on a heading of 300 degrees (0 is north). Interestingly, the winds during the first 12 hours were 15-20 kts (7-10 m/sec) at 270. This means that the buoy is tracking in a direction almost exactly opposed to the wind. The winds have since abated.

The WECOMA is close enough to shore to receive TV. While science goes on 24/7, the crew and some of the science party watched college football all day. Oregon won, USC won, Cal won... Today (Sunday) they are watching the pro football.

That's all for now from the R/V WECOMA.

Thursday, September 14 

The buoy system instruments were recovered this morning at 0530  without a  hitch.  The one pressure case that we were worrying about leaking did not. The other instrument operated perfectly except for a critical rotating part. The cold and pressure slowed its rate of rotation so the software timed out and a critical valve never was closed. The result was 200 perfect images of nothing. We understand the problem and can fix it. 

Our work here is to test equipment and failures are part of the test.

Today was more than a little crazy for the chief scientist. The Navy has declared almost all of the area we were to work in as a no boat zone.  We had to stop a long trawl in the San Clement Basin. Then we relocated to the north and the same thing happened again. Helicopters hovered over head to confirm that we were pulling inn the nets and getting under way.  I realize the importance of the job the Navy has to do, but it would have been nice if they provide us with a good alternative location. The alternative we are heading for is near the Cortez Bank. At the south tip of Cortez Bank is Bishop Rock. We need a predictably 'safe' place to deploy our float - perhaps we can do this as planned tonight.

Apart form this, all is well, the weather continues to cooperate.
 
 

Sunday 9/10
The R/V WECOMA is now at sea. We're working in a 1500 m deep depression in the seafloor called the San Clemente Basin. SCB is about 60 nautical miles west of San Diego (just south of San Clemente Island). The seafloor here would be classified as "shelf break/ upper continental slope".
 

Another 60 miles west farther out in the Pacific is "Bishop Rock" (not a relative). In reality the seabed terrain is very mushed up by tectonic activity.

We're monitoring water depth by echo sounder. We're monitoring ocean currents using an Acoustic Doppler current profiler. (This is a really complex echo sounder that measures currents by detecting the sound scattered from zooplankton).

The WECOMA has a science party of 10, Tamara Franck (Harbor Branch Ocean Institute) is chief scientist.

http://www.at-sea.org/missions/migrationmystery2/

Tamara and colleagues are interested in understanding how these  animals adapt as they age and shift from planktonic living in the euphotic zone to living at 600-700 m in the disphotic zone. More on the HBOI web page.

Tamara's group is joined by 3 high school science teachers. All with a keen interest in the ocean.

Our trip:

Todd Wood (LBNL) and I got to San Diego on Sept 9th after an all night drive from Berkeley to San Diego. We stopped for 3 hours of sleep   along the way.

We were driving a rental truck with our equipment. Our gear was aboard the ship by 1pm and about 10 hours later all was roughly placed and tied down.  We were pretty tired since we've had about 12 hours sleep in the last 4 days.

At sea:

The ship sailed on schedule at 10 am on Sept 10. About 7 hours later we were on station in the San Clemente Basin. It's now about 11 pm.  Our work is to test new instruments which will observe the day to day changes in carbon sedimentation --- for seasons. This sedimentation  is a key process of the ocean carbon cycle and is called the "biological "pump".

We want to understand how sinking carbon particles are made and how they are changed as they sink from surface waters to the deep sea.  Todd and I are going to deploy two kinds of robotic instruments. Both are designed to observe how carbon sedimentation rates fluctuate on a  day to day basis --- for seasons.

One is a free vehicle that operates independent of the ship. We call this device "Carbon Flux Explorer". It can operate as deep at 700 m.  We've never deployed this instrument package before. It's taken 5 years to develop, refine and test.  The Explorer weighs ~70 kgs and we've designed it to be neutrally buoyant in sea water (to a precision of 10 grams). The Explorer which displaces about 40 liters of seawater can change its volume by 200 ccs. By doing so, it adjusts it's density to match that of the seawater at the depth it wants to operate in. (knowing seawater density is fundamental to how any submarine operates). As a swimmer can float at the surface (because we are a little bit less dense than seawater), the Explorer will float at a particular depth in the pycnocline.

The second instrument package contains twin autonomous carbon sedimentation (flux)  recorders. It will dangle below a surface buoy at a depth of several hundred meters.

Both instruments are located by GPS satellites. The Explorer will be out of touch for most of the time below the surface. The surface buoy  of the other instrument will always let us know where it is.

We have a very long check list if things to do before we deploy these instruments. We think it will take 30 hours to get to that point. Time for bed.

Jim Bishop from R/V WECOMA.

Sunday 9/10/06 11:30pm