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Vanadium nitrogenase fuels forest moss N fixation

Vanadium nitrogenase was active in most valid moss and lichen samples across three continents, averaging about 40% of moss N2 fixation.

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Where were cryptogams collected?

Over 40 sites across 9 locations on three continents.

Which continents?

North America, South America (Chile), and East Asia (Japan).

What assay separates Mo vs alternative nitrogenases?

ISARA / LISARA using carbon-isotope fractionation of acetylene reduction.

How common was V-Nase among valid samples?

79% of valid samples; 68±20% positive across locations.

Site range of detection?

From 28% in Hokkaido to 94% in North Carolina.

How many genera showed V-Nase?

15 of 28 genera tested.

Moss vs lichen contribution to specimen BNF?

Mosses about 40% and lichens about 25% on average.

Which boreal mosses matter most for N input?

Pleurozium schreberi and Hylocomium splendens, up to 50% of circumboreal N input.

Why is Mo-independent activity attributed to vanadium?

Fe-only nitrogenase has never been found in cyanobacteria that typically fix N in cryptogams.

What happens if assays ignore alternative nitrogenases?

N input can be substantially underestimated because calibration factors differ.

Lab temperature clue?

Temperatures below 15–20 °C favor V-Nase over Mo-Nase in culture.