This has big implications for microbial ecology, biogeochemistry & evolution, since many organisms rely on diverse metals to access electron donors and acceptors. Could past changes in metal availability have shaped Earth's microbial life? Our study suggests yes! 🌏⏳ 5/6

Proteomics revealed a huge energy cost: metal-depleted cells upregulate metal transporters & fail to express key respiratory enzymes. This metal constraint may shape microbial evolution & competition in natural environments. 🔎🌍4/6

In E. coli we found that when key metals are scarce, growth slows, nitrate respiration stops, and cells shift to fermentation despite nitrate being still available! This shows metabolic choices are not just thermodynamic but also cofactor-limited. 📉🦠3/6

Microbes rely on redox reactions for energy, using terminal electron acceptors like oxygen & nitrate. But here’s the twist: their ability to use these acceptors depends on trace metals like Fe, Cu & Mo, not just availability of substrates! 🧬⚙️2/6