The bioinorganic chemistry of the ancient ocean: the co-evolution of cyanobacterial metal requirements and biogeochemical cycles at the Archean-Proterozoic boundary?

In the citing paper

“Saito et al. (2003) modeled the solubility of a suite of biologically essential trace elements (Fe, Mn, Zn, Ni, Cu, Cd, and Co) to evaluate plausible concentrations in ancient seawater under ferruginous (anoxic and Fe-rich), euxinic (anoxic and sulfide-rich), and oxic conditions (Fig. 1).”

In the citing paper

“Saito et al. (2003) emphasized that their projections of Precambrian seawater metal concentrations (Fig. 1) are based on thermodynamic models of mineral solubility and speciation in simulated seawater and are thus inherently limited.”

In the citing paper

“Similarly, based on eukaryotic cellular requirements, geochemical modeling, and the late emergence of eukaryotic Zn metalloenzymes, it was believed that Zn concentrations in the early oceans would have been a possible barrier to eukaryotic evolution (Williams and Frausto da Silva 2002;2003;Saito et al., 2003;Dupont et al., 2006;2010;Williams and Rickaby, 2012).”

In the citing paper

“The models of Saito et al. (2003) support the hypothesis that modern cyanobacterial trace element nutrient requirements may be viewed as the direct result of their early evolution in ancient oceans limited in certain trace elements (Cu, Cd, Zn) and enriched in others (Fe, Mn, Co, Ni).”

In the citing paper

“The predicted concentrations of trace elements available in the Archean oceans were in line with proposed cyanobacterial nutritional requirements but less so with the eukaryotes, which evolved much later.”

In the citing paper

“Initial estimates of Ni concentrations in the early ocean were derived from geochemical modeling (Saito et al., 2003) and microbial genomics (Zerkle et al., 2005). These studies suggested that seawater Ni concentrations were fairly uniform from the Archean through to the modern”

In the citing paper

“The presumed consistency largely stems from Ni behaving conservatively in waters under various redox conditions”

In the citing paper

“The updated view of a relatively static paleomarine Zn reservoir (Fig. 7) contradicts the findings of earlier geochemical models that linked (1) the low Zn requirements of cyanobacteria to the predicted low levels of total Zn in the Precambrian oceans, and also (2) the proliferation of eukaryotes to an increase in total Zn during the Phanerozoic”

In the citing paper

“Prior to compilations of Zn data from the sedimentary proxy record, the only estimates for Zn concentrations and bioavailability came from geochemical modeling”

In the citing paper

“In previous modeling work, researchers have pointed to the antiquity of the cobalamin cofactor, suggesting that its origin somewhere between 3.5 and 2.7 Ga is consistent with the evolution of cyanobacteria in a Co-rich ocean”

In the citing paper

“This disparity can be linked to an overestimation of the effects of Zn aqueous complexation by sulfides during the Precambrian by early geochemical models”

In the citing paper

“Modeling efforts have indicated that seawater Co concentrations could have been relatively high in the Archean, decreased in the Proterozoic, and then further decreased following Neoproterozoic ocean oxygenation”

In the citing paper

“Similar to Zn, thermodynamic modeling indicates that the seawater Cu reservoir should have reached a low in Proterozoic oceans as the result of expanded water column euxinia (e.g., Frausto da Silva and Williams, 2001;Saito et al., 2003).”