Trends in soil characteristics along a recently deglaciated foreland on Anvers Island, Antarctic Peninsula

摘要

We assessed patterns in soil development at a recently deglaciated foreland on Anvers Island on the Antarctic Peninsula. Soil samples were collected along transects extending 35 m over bare ground from the edge of a receding glacier; the far end of these transects has been ice free for approximately 20 years. We also compared soils at the far end of these transects under bare ground to those under canopies of isolated individuals of Des-champsia antarctica, a caespitose grass, that had recently colonized the site (established for <6 years). In addition, we compared soils at this young foreland to those in a well-developed tundra island that has been ice free for at least several hundred years. At the foreland site, soil moisture was greatest near the glacier, consistent with proximity to meltwater, and declined with distance from the glacier. This decline in soil moisture may explain the decrease in litter decomposition rates and the greater soil nitrate (NO_3~-) concentrations that we observed with distance from the glacier. The greater soil moisture near the glacier likely promoted leaching and transport of NO_3~- to drier soils away from the glacier. The presence of D. antarctica at the glacier foreland had little effect on soil properties, which is not surprising considering it had only colonized sampling areas during the previous 5 years. Compared to the foreland, which contained only mineral soil, soil at the older tundra site had a 2.5- to 5-cm-thick organic horizonrnthat had much higher concentrations of total carbon, nitrogen, and NO_3~-.