Iron hypothesis

Martin, J. H. (1990). Glacial-interglacial CO2 change The iron hypothesis. Paleoceanography 5,1-13. 

Martin, J. H. et al. (1994). Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean. Nature 371,123-129. 

Evidence in support of the Iron Hypothesis has been obtained from ice cores that contain records of past dust deposition, atmospheric CO2 levels and global temperatures. As shown in Figure 5.13, during the past 160,000 years, periods during which dustborne iron levels have been high coincide with lower atmospheric CO2 levels and global temperatures, i.e., the most recent Ice Ages. 

A tremendous amoimt of research has since been conducted to investigate various components of the Iron Hypothesis because of the potential linkage to climate control. This connection has even led to the proposal that we iron our way out of our current greenhouse gas problem Particular attention has been paid to determining... 

Body iron level and iron depletion play an important role in the gender differences seen in death from cardiac disease. There is a better correlation with heart disease mortality in iron levels compared with levels of cholesterol (5). It was found that risk of coronary heart disease (6) and carotid atherosclerosis (7) is associated with increased iron stores. However, impaired endothelium-derived nitric oxide activity may be without overt atherosclerosis in patients with risk factors and may be associated with the presence of atherosclerosis (4). Thus, endothelial dysfunction related to iron activity not only may be an early marker for cardiovascular risk but also may contribute to the pathogenesis of atherosclerosis (2) by the stimulation of low-density lipoproteins (LDL) and membrane lipid peroxidation (I) and may be a key to the understanding of early mechanism in the development of atheroma (7,8). Nakayama et al. (9) showed the role of heme oxygenase induction in the modulation of macrophage activation in atherosclerosis. However, Howes et al. (10) concludes that at the moment, the available evidence on iron hypothesis remains circumstantial. Moreover, Kiechl et al. (7) showed that the adverse effect of iron is hypercholesterolemia, In patients... 

Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean. Nature 371, 123—126. Mayer, M. S., Schaffner, L., and Kemp, W. M. (1995). Nitrification potentials of benthic macrofaunal tubes and burrow walls Effects of sediment NH4" and animal irrigation behavior. Mar. Ecol. Prog. Ser. 121, 157-169. 

Strass V. H. (2002) EisenEx-1 test of the iron hypothesis in a Southern Ocean eddy. EOS Trans., AGU Abstracts of2002 Ocean Sciences Meeting. 

K., Kolber Z., Greene R., FalkowsM P., Chishohn S. W., Hoge F., Swift R., Yungel J., Turner S., Nightingale P., Hatton A., Liss P., and Tindale N. W. (1994) Testing the iron hypothesis in ecosystems of the equatorial Pacific Ocean. Nature ill, 123-129. 

The role of Fe as a limiting nutrient has been well established in the last decade in the so-called high-nutrient low chlorophyll regions of the oceans. A series of massive iron seeding experiments carried out to test the iron hypothesis advanced by Martin and Fitzwater (1988) have unequivocally shown that iron supply limits plankton production in one third of the world s oceans, despite the perennially high surface concentration of macronutrients (Fig. 7.1). The dynamics of phytoplankton blooms are limited by iron supply, which... 

Martin, J.H. (1990) Glacial-interglacial C02 changes the iron hypothesis. Paleoceanography, 5, 1-13. 

If iron is a limiting micronutrient for present-day PP, it may be an important link to explain glacial-interglacial climatic cycles of the past. Martin (1990) postulated the iron hypothesis which explains decreased atmospheric CO concentrations during glacial times with increased iron deposition by aeolian input resulting in increased PP and thus increased CO -... 

Fig. 7.7 Fe and CO concentrations of the Antarctic Vostok ice core for the past 160,000 years (adopted from De Angelis et al. 1987). Measured Al concentrations were converted to Fe concentrations according to the average continental crust composition. The negative correlation of COj and Fe supports the iron hypothesis (see text).

Berger WH, Wefer G (1991) Productivity of the glacial ocean Discussion of the iron hypothesis. Littmol Oceanogr 36 1899-1918... 

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