02340nas a2200181 4500008004100000022001300041245009000054210006900144260001200213490000800225520176100233100001601994700001702010700002202027700002002049700002302069856006602092 2018 eng d a0038071700aSoil biological responses to C, N and P fertilization in a polar desert of Antarctica0 aSoil biological responses to C N and P fertilization in a polar  c07/20180 v1223 a

 

In the polar desert ecosystem of the McMurdo Dry Valleys of Antarctica, biology is constrained by available liquid water, low temperatures, as well as the availability of organic matter and nutrient elements. These soil ecosystems are climate-sensitive, where projected future warming may have profound effects on biological communities and biogeochemical cycling. Warmer temperatures will mobilize meltwater from permafrost and glaciers, may increase precipitation and may be accompanied by pulses of nutrient availability. Enhanced water and nutrient availability have the potential to greatly influence desert soil biology and ecosystem processes. The objectives of this 5-year study were to determine which nutrient elements (C, N, P) are most limiting to dry valley soil communities and whether landscape history (i.e., in situ soil type and stoichiometry) influences soil community response to nutrient additions. After 3 years of no noticeable response, soil CO2 flux was significantly higher under addition of C+ N than the other treatments, regardless of in situ soil stoichiometry, but microbial biomass and invertebrate abundance were variable and not influenced in the same manner. A stable isotope incubation suggests that fertilization increases C and N mineralization from organic matter via stimulating microbial activity, with loss of both the applied treatments as well in situ C and N. However, these responses are relatively short-lived, suggesting long-term impacts on C and N cycling would only occur if meltwater and nutrient pulses are sustained over time, a scenario that is increasingly likely for the dry valleys.

 

1 aBall, Becky1 aAdams, Byron1 aBarrett, John, E.1 aWall, Diana, H.1 aVirginia, Ross, A. uhttp://linkinghub.elsevier.com/retrieve/pii/S0038071718301081