Hungry Oceans Dummies' Guide

The Theory

* A long time ago, oceanographers established that the ratio of carbon to nitrogen and phosphorous in the ocean was the same everywhere. For every one molecule of phosphate in the upper ocean, there are 16 molecules of nitrate and 106 molecules of carbon. 

* Professors Dave Karl and Ricardo Letelier have been studying the North Pacific Subtropical Gyre for more than 20 years.  They know its characteristics very well and are well published on the subject. 

* They know that the deep ocean is packed with nutrients.  As the largest and oldest ocean on Earth, the Pacific has a rich store of nutrients locked up in the deep.  Ricardo and Dave want to use the pumps to bring these nutrients to the surface.  This will act like a fertilizer and most likely trigger a bloom of diatoms.

* Diatoms are heavy and sink fast.  They have dense carbonate shells, which helps to protect them from predation, while locking up lots of carbon. 

* The pumps will release nutrients from the deep, but they will also bring dissolved carbon dioxide up to the surface.  This has been a major argument against the pumps — that they will cause more harm than do good.  However, Ricardo and Dave say this initial bloom of diatoms will re-absorb the CO₂ released from the deep.  This first bloom makes the pumps "carbon neutral."

* The pumps supply nitrate and phosphate to the surface.  They also supply many other nutrients.  Phosphate is the key – it is vital for the reproduction of the plankton.  As the diatoms proliferate in these rich nutrient conditions, the bloom grows massively.  But it will reach a point where the bloom has grown faster than the nutrients are being supplied.  The edges of the bloom will start struggling.  Nitrate becomes limited in that region.  Dead diatoms contain phosphate that other plankton can absorb for their growth; all the while more phosphate is pumped into the region. 

* The limited nitrate region will trigger a new type of bloom — a nitrogen-fixing bloom.  Dave and Ricardo expect to see the nitrogen fixer, called "Trichodesmium," grow.  This plankton takes nitrogen directly from the atmosphere and converts it into a usable form for other plankton (called "nitrates").

* The "Trichodesmium" bloom acts as a fertilizer for further diatom growth.  This bloom has the potential to absorb up to five times as much CO₂. 

Final Experiment Details

* The team will deploy a single pump, 1,000 feet long, held 50 feet below the surface.  This pump is packed with sensors attached to the valve, the mid-coupler and the top. It will record temperature readings at each stage, and measure whether deep water is pumping upwards.  A current meter, called the MAV-3, will tell the team how efficient the pump is working. 

* The buoy will be deployed first.  Then the pancake roll of piping will be dropped in.  The ship will move forward slowly at about 2.5 knots, allowing the piping to unravel.  The valve will be dropped in last, and the weight of the valve will pull the pumping vertically down into the water.  The twists in the piping should unravel themselves during this stage.  Last of all, the recovery float — attached via a long line to the valve — will be deployed.  The float will aid in the recovery of the pump.

* For the vision to work, the team must test whether these pumps can be tethered together.  So they'll deploy two of these pumps — identical in structure — 300 feet apart.  The first pump will be deployed in reverse — valve first, buoy last.  The ship will move forward as the tether is paid out.  The second pump will go in buoy first, then the valve.

* Three state-of-the-art seagliders will be deployed in the water.  These autonomous underwater robots will transect the path of the pumps and measure for any chemical or biological activity. 

* Seagliders monitor temperature, salinity, oxygen, chlorophyll production and nutrient levels.  They beam the data back to the mainland via GPS and satellite phone, so Dave and Ricardo can monitor exactly what is happening. They will also use satellite data to track the progress of the pumps.

* Computer modelers have already super-sized the technology to a planetary scale.  But no one knows how these pipes will work in practice. Within a few hours, the pumps should be steadily operating.