The Iron Hypothesis predicts that if portions of the ocean were seeded with iron, a plankton bloom would result, sucking carbon dioxide out of the atmosphere and offsetting the greenhouse effect. A new LBNL article says three robotic Carbon Explorer floats, launched by scientists from Lawrence Berkeley National Laboratory as part of the Southern Ocean Iron Experiment (SOFeX) tracked a small-scale test of the hypothesis and seem to support the theory. They measured a four-fold growth of plankton over a two-month period and collected data that indicates the plankton fix carbon dioxide and send it to the ocean floor. The Carbon Explorer robots are modified versions of the SOLO floats that we've reported on before.