Chris Neill (12.07.09)

Give journalists some iron and they’ll start an ice age.

Well, not exactly. But today at Palmer, MBL Logan Science Journalism Fellows Scott Canon, Angela Posada-Swafford and Jason Orfanon began experiments that are designed to test the hypothesis that very low concentrations of iron limit the growth rate of algae in the vast Southern Ocean.

That idea led oceanographer John Martin of Moss Landing Marine Laboratory to utter the famous line, “Give me half a tanker of iron, and I’ll give you an ice age,” to an informal seminar at the Woods Hole Oceanographic Institution in 1988.

Martin’s idea was straightforward. Add iron to the Southern Ocean, phytoplankton grow, are eaten by zooplankton. Zooplankton fecal pellets sink to the bottom and carry carbon with them—locking it in the oceans’ depths and out of the atmosphere for thousands of years.

The earth’s largest mass of moving water, the Antarctic Coastal Current, hits land on the west side of the Antarctic Peninsula, right where Palmer sits. It’s a perfect place to run out in a Zodiac and grab water that represents water of the great Southern Ocean.

The waters around Palmer are high in nitrate, a form of the nutrient nitrogen that limits the growth of algae in much of the warmer ocean—like around Woods Hole, where chronic nitrogen inputs from septic systems cause algae to bloom.

The journalists have assembled 12 large plastic bottles, or carboys, that hold 50 liters (13 gallons) of water each. They run to “Station B,” about 400 meters out from Bonaparte Point, one of the two points that define Palmer’s protected Hero Inlet.

They load four carboys at a time into their Zodiac (they have been assigned number “66) and motor out through small pieces of “brash ice.”

Back at the dock, Palmer Boating Supervisor John Fonseca maneuvers the Sky Track, picks up the filled carboys (50 kg, or 110 pounds each) and carefully places them onto a wooden platform, where they’ll sit for the next ten days.

Scott, Angela and Jason will do in bottles near the dock what oceanographers recently did from ships in the Southern Ocean. They will add traces of iron and follow the production of chlorophyll, the key molecule that allows algae to fix carbon dioxide and grow. Chlorophyll is easy to measure and is directly related to the amount of phytoplankton in the water.

The 12 carboys will be assigned to four treatments. To one set of three carboys the journalists add an iron-containing solution. They hypothesize chlorophyll will increase over time. To another set of three carboys the journalists add nitrate. If it’s iron and not nitrate that controls the plankton, nothing should happen. Another set of three carboys gets nothing added—it will serve as an experimental control.

The last group of three carboys will examine the effect of grazing as a control on phytoplankton. The grazers of import her are Antarctic krill (Euphausia superba). -But the journalists have to find the krill. They haven’t appeared in great numbers yet this year. So the krill hunters jump in the Zodiacs with nets and a five-gallon bucket.

Each time boaters go out on the water at Palmer, they bundle up in long underwear, fleece and orange, floatable Mustang suits. They also take along two radios so they can call the Station radio operator to tell him when they leave, where they are going, and when they arrive on station.

Each day, boating groups make up different creative names for their boats.  Today, our journalists are “Dressed to Krill.”