Thread by @silva_lcr

In 2021, #Brazilian scientists led an international collaboration which resulted in unexpected results presented as “A New Hypothesis for The Origin of #AmazonianDarkEarths”

https://twitter.com/silva_lcr/status/1346139041448615936?s=20&t=GmYM_j3AdRKasi9MrR5WLQ

A brief thread

Those findings were misconstrued by some in the media as an attack on #indigenous peoples and their traditions in the #Amazon region. This couldn’t be farther from the truth.

#AmazonianDarkEarths (ADE) are widely regarded as a model for sustainable agriculture. Their unusual fertility and elevated concentration of charcoal, has prompted industrial-scale biomass burning to make products for soil amendment.

However, it remains unclear how these persistent patches of high fertility were formed and maintained in nutrient-impoverished landscapes.

New data from one of the best-studied ADE sites in Brazil warrants a revision of its origin story. nature.com/articles/s4146…

Charcoal 14C suggests inputs thousands of years before the earliest evidence of biomass burning for agriculture. Large amounts of P & Ca (a common proxy for human input) correlate with 16 elements + Ne Sr & C isotopes that indicate exogenous sources rather than in situ deposition

Taken together, the results imply that #indigenous populations either managed soils at the site thousands of years earlier than previously reported or, alternatively, that human-derived inputs represent a small fraction of ADE’s chemical makeup

This idea attracted a lot of attention (eg the original paper ranks in the 98th all articles of a similar age in all journals & 91st percentile of articles @NatureComms), which is surprising given the growing importance of more pressing issues (eg #pandemic and #climatechange)

However, it also attracted undue criticism as an attempt to resurrect an outdated #colonial view of Amazonia as a pristine environment, which is a false premise.

In response to those who misconstrued the findings, a new analysis published today nature.com/articles/s4146… supports the original conclusion that “indigenous peoples harnessed natural processes of elemental deposition, which led to the unique properties of ADEs"

Data from a single site cannot be extrapolated across the region but the findings above raise general questions about the timing & mechanisms of ADE formation warranting a revision of the current model for sustainability in the region

To solve the mystery and inform sustainable management we argue for new "interdisciplinary research that combines indigenous knowledge, neotectonics, fluvial geomorphology, and a modern understanding of elemental cycling”

Putting money where our mouth is, we have now secured funding to test the new hypothesis (see above) across large portions of the #Amazon basin. Our team will prioritize working with local communities and researchers.

This is a team science effort where people from different disciplines and backgrounds are welcome. If you work in the #Amazon + want to contribute samples, time, or expertise please contact me to learn about funding opportunities. We will launch the project in September .Obrigado