Phosphatization under birds' activity: Ornithogenesis at different scales on Antarctic Soilscapes

•Penguins’ colonies account for a high degree of soil phosphatization and chemical weathering.•Penguins are key drives of P and organic matter sea land transfers in Maritime Antarctica.•High organic-P contents in soils indicate penguins directly influencing the landscape evolution following glacial retreat.•Penguins promote changes in the ecological succession of ice-free areas of Maritime Antarctica. Extensive areas of penguins’ nesting (Pygoscelis sp.), on ice-free areas, account for vast deposits of organic matter-rich guano in maritime Antarctica. One such area, at Harmony Point, currently houses different penguin colonies with extensive and unique ornithogenic soils, where phosphatization is the key soil-forming process. We sought to enhance the knowledge of phosphatization process, products, cycles, and phosphorus (P) forms in these unusual soils. We compared ornithogenic and non-ornithogenic soils, based on advanced chemical, micromorphological and mineralogical analyses of samples of guano and phosphate biocrusts, complete with P and OM fractionation. Ornithogenic soils have the organic P-pool as the largest phosphorous compartment, followed by varying P-Ca forms. In contrast, soils unaffected by phosphatization showed a high inorganic P-pool. Penguin guano is enriched with P, Ca, K, Cu, Zn, C and N. The phosphatic biocrusts are composed of struvite and hydroxyapatite, forming a gradient of phosphate forms. We recognized three different phosphatization environments, namely (i) present-day marine birds’ rookeries, (ii) adjacent zone of rookeries and (iii) abandoned rookeries. Geomorphological evolution of the coastal areas, by Holocene glacier retreat, resulted in the changing location of penguin colonies, resulting in a larger area and varying ages of phosphatization, forming ornithogenic soils with contrasting evolution degrees. Abandoned areas have greater vegetation growth, with higher diversity.