• "Moss Landing Researchers Reveal Iron as Key to Climate Change"
• "Open Ocean Iron Fertilization for Scientific Study and Carbon Sequestration"
  
• "Rapid and early export of Phaeocystis antarctica blooms in the Ross Sea, Antarctica"
• "Robotic Observations of Enhanced Carbon Biomass and Export at 55ºS During SOFeX"
  
• "Report on the 2002 US JGOFS Workshop on Iron Dynamics in the Carbon Cycle"

Moss Landing Researchers Reveal Iron as Key to Climate Change
Moss Landing Marine Laboratories
April 15, 2004
For full text click here.
SOFEX Cruise log and background information is available at: http://www.mbari.org/expeditions/SOFeX2002/

Excerpts: "Previous studies have suggested that during the last four ice ages, the Southern Ocean had large phytoplankton populations and received large amounts of iron-rich dust, possibly blown out to sea from expanding desert areas. In order to simulate such ice-age conditions, the SOFeX scientists added iron to surface waters in two square patches, each 15 kilometers on a side, so that concentrations of this micronutrient reached about 50 parts per trillion. This concentration, though low by terrestrial standards, represented a 100-fold increase over ambient conditions, and triggered massive phytoplankton blooms at both locations. These blooms covered thousands of square kilometers, and were visible in satellite images of the area.

"Each of these blooms consumed over 30,000 tons of carbon dioxide, an important greenhouse gas. Of particular interest to the scientists was whether this carbon dioxide would be returned to the atmosphere or would sink into deep waters as the phytoplankton died or were consumed by grazers. Observations by Dr. Ken Buesseler of Woods Hole Oceanographic Institution and Dr. Jim Bishop of Lawrence Berkeley National Laboratories indicate that much of the carbon sank to hundreds of meters below the surface. When extrapolated over large portions of the Southern Ocean, this finding suggests that iron fertilization could cause billions of tons of carbon to be removed from the atmosphere each year. Removal of this much carbon dioxide from the atmosphere could have helped cool the Earth during ice ages. Similarly, it has been suggested that humans might be able to slow global warming by removing carbon dioxide from the atmosphere through a massive ocean fertilization program."

"Open Ocean Iron Fertilization for Scientific Study and Carbon Sequestration"
(Report for the US Department of Energy)
by K. Coale
Moss Landing Marine Laboratories
Moss Landing, California 95039
For full report click here.

Excerpts: Findings to Date - Biophysical Response
"In general, all members of the High Nitrate, Low Chlorophyll (HNLC) photosynthetic community are physiologically limited by iron availability. This observation is based primarily on the examination of the efficiency of photosystem II, the light harvesting reaction centers. At ambient levels of iron, light harvesting proceeds at sub-optimal rates... When iron concentrations are increased by sub-nanomolar amounts, the efficiency of light harvesting rapidly increases to maximum levels...

Growth Response
"When iron is present, phytoplankton growth rates increase dramatically (Coale, et al., 1996; Fitzwater et al., 1996). These and other experiments, over widely differing oceanographic regimes, have demonstrated that, when light and temperature are favorable, phytoplankton growth rates in HNLC environments increase to their maximum at dissolved iron concentrations generally below 0.5 nM... The iron induced transient imbalance between phytoplankton growth and grazing in the equatorial Pacific during IronEx II resulted in a 30 fold increase in plant biomass ( Coale et al., . Similarly, a six fold increase was observed during the SOIREE experiment in the Southern Ocean. These are perhaps the most dramatic demonstrations of iron limitation of nutrient cycling, and phytoplankton growth to date and has fortified the notion that iron fertilization may be a useful strategy to sequester carbon in the oceans...

Conclusions
"The notion of both scientific experimentation through manipulative experiments, as well as the use of iron to purposefully sequester carbon is gaining momentum. There are now national, international, industrial, and scientific concerns willing to support larger scale experiments. The materials required for such an experiment are inexpensive and readily available even as industrial byproducts (paper, mining, steel processing). Given the concern over climate change and the rapid modernization of large developing countries (China, India, etc...) there is a pressing need to address the increased emission of greenhouse gasses. Through the implementation of the Kyoto accords or other international agreements to curb emissions (Rio), financial incentives will reach into the multi-billion dollar level annually. Certainly there will soon be an overwhelming fiscal incentive to investigate, if not implement purposeful open ocean carbon sequestration trials."

Rapid and early export of Phaeocystis antarctica blooms in the Ross Sea, Antarctica
(Letters to Nature)
by G. R. DiTullio, J. M. Grebmeier, K. R. Arrigo, et al.
Nature magazine
April 6, 2000
For full text click here.

Excerpts: "The Southern Ocean is very important for the potential sequestration of carbon dioxide in the oceans and is expected to be vulnerable to changes in carbon export forced by anthropogenic climate warming. Annual phytoplankton blooms in seasonal ice zones are highly productive and are thought to contribute significantly to CO2 drawdown in the Southern Ocean. Diatoms are assumed to be the most important phytoplankton class with respect to export production in the Southern Ocean; however, the colonial prymnesiophyte Phaeocystis antarctica regularly forms huge blooms in seasonal ice zones and coastal Antarctic water... Here we present evidence for early and rapid carbon export from P. antarctica blooms to deep water and sediments in the Ross Sea. Carbon sequestration from P. antarctica blooms may influence the carbon cycle in the Southern Ocean, especially if projected climatic changes lead to an alteration in the structure of the phytoplankton community...

Our results indicate that the episodic sinking of colonial P. antarctica blooms may not require bloom senescence conditions, a fact that may facilitate the continuous drawdown of pCO2 during the austral summer. Thus, early bloom conditions in the Ross Sea may be important with respect to carbon export from surface waters, particularly as P. antarctic blooms remove about twice as much CO2 per mole of PO4 relative to diatoms.

Robotic Observations of Enhanced Carbon Biomass and Export at 55ºS During SOFeX
(Science magazine Report)
by James K.B. Bishop, Todd J. Wood, Russ E. Davis, and Jeffrey Sherman
Science, Vol. 304
April 16, 2004
For full text click here.

Abstract
Autonomous floats profiling in high-nitrate low-silicate waters of the Southern Ocean observed biomass variability and carbon exported to depths of 100 m during the 2002 Southern Ocean Iron Experiment (SOFeX) to detect the effects of iron fertilization of surface waters there. Control and "in-patch" measurements documented a greater than fourfold enhancement of carbon biomass in the iron-amended waters. Carbon export through 100 m increased two- to six-fold as the patch subducted below a front. The molar ratio of iron added to carbon exported ranged between 10⁴ and 10⁵. The biomass buildup and export were much higher than expected for iron-amended low-silicate waters.

Report on the 2002 US JGOFS Workshop on Iron Dynamics in the Carbon Cycle
Kenneth S. Johnson, J. Keith Moore and Walker O. Smith
Moss Landing, California
For full text click here.

Introduction
A US JGOFS Workshop on Iron Dynamics in the Carbon Cycle was held at the Monterey Bay Aquarium Research Institute in Moss Landing, California on June 17 to 19, 2002. The Workshop was attended by a mix of observationalists from the US JGOFS field programs, as well as other projects, and a group of modelers. The goals for the meeting were:

• To synthesize recent results from observational work and modeling efforts.
• To examine how models are currently incorporating iron dynamics, and to determine whether there is new information that could be used to improve parameterizations/representations in the models.
• To identify critical gaps in our knowledge of the marine iron cycle that are hampering modeling efforts, and to provide suggestions for future research.