02348nas a2200217   4500008004100000022001400041245012100055210006900176260001200245520149200257653001101749653001801760653002201778653001501800653001301815653001701828100002101845700002301866700002201889856021901911       2025                        eng d  a0954-102000aMicrobial mat activity and soil biogeochemistry across variable phosphorus availability in Taylor Valley, Antarctica0 aMicrobial mat activity and soil biogeochemistry across variable   c05/20253 a<p>Primary production is fundamental to ecosystems, and in many extreme environments production is facilitated by microbial mats. Microbial mats are complex assemblages of photo- and heterotrophic microorganisms colonizing sediment and soil surfaces. These communities are the dominant producers of the McMurdo Dry Valleys, Antarctica, where they occupy lentic and lotic environments as well as intermittently wet soils. While the influence of microbial mats on stream nutrient dynamics and lake organic matter cycling is well documented, the influence of microbial mats on underlying soil is less well understood, particularly the effects of microbial mat nitrogen and carbon fixation. Taylor Valley soils occur across variable levels of inorganic phosphorus availability, with the Ross Sea drift containing four times that of the Taylor drifts, providing opportunities to examine how soil geochemistry influences microbial mats and the ecological functions they regulate. We found that inorganic phosphorus availability is positively correlated with microbial mat biomass, pigment concentration and nitrogen fixation potential. Additionally, our results demonstrate that dense microbial mats influence the ecological functioning of underlying soils by enriching organic carbon and total nitrogen stocks (two times higher). This work contributes to ongoing questions regarding the sources of energy fuelling soil food webs and the regional carbon balance in the McMurdo Dry Valleys.</p>10acarbon10acyanobacteria10anitrogen fixation10aphosphorus10apigments10asoil ecology1 aPower, Sarah, N.1 aOsburn, Ernest, D.1 aBarrett, John, E.  uhttps://www.cambridge.org/core/journals/antarctic-science/article/microbial-mat-activity-and-soil-biogeochemistry-across-variable-phosphorus-availability-in-taylor-valley-antarctica/0655E2F09B8D6961618B8F396BA692F2