The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis

Kopp et al. 10.1073/pnas.0504878102.

Supporting Information

Files in this Data Supplement:

Supporting Text
Supporting Figure 2

Supporting Figure 2

Fig. 2. Results of the nutrient flux model of net oxygen production by oxygenic photosynthesizers. (a) Modeled O₂ production at different levels of P and Fe flux into the photic zone. Contours are labeled in bars of net O₂ per y. Following Bjerrum and Canfield (1) we assumed a C burial efficiency of 0.019, a C/P ratio of 185, a P adsorbtion onto Fe(III) constant of 0.07 mM^–1, and mixing velocity of 1.26 × 10¹⁸ L/y. All of the P flux and 10% of the Fe flux were assumed available for biological use. The upper, diagonal portions of the contours represent P limitation, and the lower, horizontal portions represent Fe limitation. (b) Modeled O₂ production at varying C burial efficiency and C/Fe ratio. Except for C burial efficiency, parameters are as in a, with P and Fe flux fixed. Observed C/Fe ratios for modern field populations of Trichodesmium range from <2,000 to 50,000.

1. Bjerrum, C. J. & Canfield, D. E. (2002) Nature 417, 159–162.