Soil pockets phosphatization and chemical weathering of sites affected by flying birds of Maritime Antarctica.

Daví Do Vale Lopes,José João L.L De Souza,Fábio S De Oliveira,Carlos Ernesto G.R Schaefer,Mariana De Resende Machado

doi:10.1590/0001-3765202220210595

Abstract

The majority of ornithogenic soils studied in Antarctica focus on the influence of penguins, wherever little reports evaluated the influence of flying birds on soil genesis. This study aimed to characterize the morphologic, chemic, physic, mineralogic, and micromorphologic ornithogenic soil pockets influenced by flying birds in Snow Island, Maritime Antarctica. Fifteen soil pockets were selected, described, sampled and analyzed, these sites constitute the main areas with intense long-term terrestrial biological activity in Snow Island. In order to investigate the impact of phosphatization, we compared the soil pockets with the surrounding soils and soils affected by penguins. Zone of phosphatization have a high concentration of P, K, and Ca. The XRD patterns for the clay fraction of ornithogenic soils show that phosphate minerals are the main crystalline phases (leucophosphite, minyulite, fluorapatite, and apatite). We show that even under typical periglacial conditions, sites influenced by flying birds present active chemical weathering processes. The phosphatization release exchangeable bases and accelerate mineralogical and micromorphological transformations in soils. Under the current global warming trend and expected sea-level rise, the ornithogenic environments are susceptible to accelerated erosion rates and a great part of these hotspots may be lost for the open sea.

Highlights

Ornithogenic soils are composed by mineral and organic materials influenced by birds (Ugolini 1972, Simas et al 2007)
The majority of ornithogenic soils studied in Antarctica focus on the influence of penguins, wherever little reports evaluated the influence of flying birds on soil genesis
The ornithogenic soil pockets of President Head Peninsula (PHP) showed a mean of 46% of gravels (Table I), with textural range from clay loam to loamy sand, while sandy clay loam is the main soil texture (Table I)

Summary

Introduction

Ornithogenic soils are composed by mineral and organic materials influenced by birds (Ugolini 1972, Simas et al 2007). They often have a high content of gravels that has been transported by birds and are identified by other features such as bones, carcasses, eggshells, and feathers (IUSS Working Group WRB 2014). The ornithogenic soils of this region are unique in Antarctica and represent important sites where phosphatization is the main soilforming process (Simas et al 2007, Daher et al 2019, Lopes et al 2019). These conditions favor the formation of deep and clayey soils. Processes, and transformation systems in phosphatized environments of flying birds are poorly known, compared with those under penguins

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