Surface and subsurface flows of nutrients in natural and humanimpacted lake catchments on Broknes, Larsemann Hills,Antarctica

[摘要] This study aimed to use nutrients in lake inflows as proxies for assessing human impact andseparating this from natural transformations of material in the soil active layer. Nutrients, conductivity andδ18O were monitored in surface and subsurface (using ceramic tipped piezometers) lake inflows duringsummer in near natural and human impacted catchments. The nutrient levels were highly variable butgenerally higher during the last weeks of the flow, in both subsurface waters and in human impactedcatchments. Up to 2000 μgN l−1 subsurface dissolved inorganic nitrogen (DIN) was measured in humanimpacted catchments but only 315 μg N l−1 in natural catchments. Subsurface levels of dissolved reactivephosphorus (DRP) were up to 310 μgP l−1 in natural catchments and up to 108 μgP l-1 in human impactedcatchments. The maximum levels of both DIN and DRP in surface inflows were much higher in humanimpacted than in natural catchments. Conductivity and δ18O data showed general enrichment of snowbankmeltwater presumably through evaporation from the active layer. This combined with fluctuating nutrientlevels in catchment waters indicated that soil brines and decaying organic matter of natural and human originwere possible sources for nutrients and other salts. Marked salinization and substantially increased DINlevels near the research stations indicated that lake waters were receiving nutrients generated by humans.

[学科分类] 自然科学（综合）