Rock weathering creates oases of life in a high Arctic desert.
During primary colonization of rock substrates by plants, mineral weathering is strongly accelerated under plant roots, but little is known on how it affects soil ecosystem development before plant establishment. Here we show that rock mineral weathering mediated by chemolithoautotrophic bacteria is associated to plant community formation in sites recently released by permanent glacier ice cover in the Midtre Lovénbreen glacier moraine (78 degrees 53'N), Svalbard. Increased soil fertility fosters growth of prokaryotes and plants at the boundary between sites of intense bacterial mediated chemolithotrophic iron-sulfur oxidation and pH decrease, and the common moraine substrate where carbon and nitrogen are fixed by cyanobacteria. Microbial iron oxidizing activity determines acidity and corresponding fertility gradients, where water retention, cation exchange capacity and nutrient availability are increased. This fertilization is enabled by abundant mineral nutrients and reduced forms of iron and sulfur in pyrite minerals within a conglomerate type of moraine rock. Such an interaction between microorganisms and moraine minerals determines a peculiar, not yet described model for soil genesis and plant ecosystem formation with potential past and present analogues in other harsh environments with similar geochemical settings.
Department of Food Science and Microbiology, University of Milan, I-20133 Milan, Italy.
Sara
S
Borin
Stefano
S
Ventura
Fulvia
F
Tambone
Francesca
F
Mapelli
Florence
F
Schubotz
Lorenzo
L
Brusetti
Barbara
B
Scaglia
Luigi P
LP
D'Acqui
Bjørn
B
Solheim
Silvia
S
Turicchia
Ramona
R
Marasco
Kai-Uwe
KU
Hinrichs
Franco
F
Baldi
Fabrizio
F
Adani
Daniele
D
Daffonchio
D001110:Arctic Regions; D001419:Bacteria / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D000458:Cyanobacteria / Q000378:metabolism; D003889:Desert Climate; D017753:Ecosystem; D046448:Ice Cover / Q000382:microbiology; D009584:Nitrogen / Q000378:metabolism; D063245:Plant Development; D018517:Plant Roots / Q000382:microbiology; D012987:Soil; D012988:Soil Microbiology; D013538:Svalbard
D012987:Soil; D002244:Carbon; D009584:Nitrogen