The guano of penguins,other seabirds,and pinnipeds is an important source of phosphorus in the ecosystems of Antarctica.To study the vertical distribution of phosphorus in sediments influenced by penguins,we measured phosphorus forms in two sediment cores(G1 and Q2)from ephemeral ponds on Ardley Island.We also investigated the correlations between these phosphorus forms and physicochemical characteristics.Inorganic phosphorus was the main form of phosphorus in both cores.The vertical distribution patterns of phosphorus forms in G1 and Q2 differed,indicating different sedimentary sources.The G1 sediment profile was more influenced by penguin guano than the Q2 profile,and as a result sediments in the G1 core had higher total phosphorus,non-apatite inorganic phosphorus,and apatite phosphorus content.The findings from two ephemeral ponds on Ardley Island indicate that the contribution of penguin guano to organic matter in G1 core has increased in recent times,while Q2 showed a relatively larger contribution from mosses in ancient times,evident from the lithology and the vertical trend in organic matter.