Robert McGrath's Blog (EUA)

Tie Between Undersea Microbes and Manganese Nodes

Publicado em 23 abril 2021

One of the few ecological niches that humans haven’t mucked up yet is the Earth’s crust.  We know very little about whatever lives there, not least because we can’t really go there. And one of the most fascinating parts of this niche is the world wide archipelago of undersea volcanic vents.  Tube worms!  Who knew?

This spring, researchers from Universidade de São Paulo report an interesting study of the Rio Grande Rise, a sea mount in the Atlantic [1].  Like many undersea areas, this location is covered with a mineral crust of Fe–Mn.  These deposits are potentially valuable resources, though not much is known of their origin.

The new study examine the microbial life living on the mineral crust, sequencing DNA to survey the diversity and nature of the community.  This required careful sampling at 1000+ meters, isolating each sample to prevent cross contamination.

They found a lot of life, Bacteria and Archea, varying with depth.  Many of the species were similar to those found in other locations, opening the question of how they might disperse across long distances (e.g., from South Africa to Brazil).

Now, I know nothing about the details of undersea (or any) microbe physiology, so I’m relying on their summary for the details of what these microbes eat and poop:  “This is strong evidence that the metals there are formed not just by a geological process but also by a biological process in which microorganisms play an important part,” (Natascha Menezes Bergo, quoted in [2])

In other words, these mineral deposits may be the result of microbial action.  Of course, the picture is far from simple, because there are many species, and we don’t understand all the dependencies and flows.

But this is neat.

It’s hard to know if there are practical implications.  It seems to me that it would be wise to know more before large scale exploitation begins.  Understanding the ecology might provide understanding of the distribution of valuable minerals. And these microbes might be useful markers for locating hidden deposits.  Or there may even be ways to enhance production of the economically valuable minerals, which might lead to sustainable “farming” rather than simple extraction.

  1. Natascha Menezes Bergo, Amanda Gonçalves Bendia, Juliana Correa Neiva Ferreira, Bramley J. Murton, Frederico Pereira Brandini, and Vivian Helena Pellizari, Microbial Diversity of Deep-Sea Ferromanganese Crust Field in the Rio Grande Rise, Southwestern Atlantic Ocean. Microbial Ecology,   2021/01/16 2021.
  2. André Julião, Microorganisms on the Rio Grande Rise are a basis for deep-sea life and a possible origin of metals, in Agência FAPESP – News, April 14, 2021.