The biogeochemistry of insectivorous cave guano: a case study from insular Southeast Asia

Abstract

Cave guano derived from insectivorous bats and birds contain unique geochemical and mineralogical signatures. We investigated the mineralogy, pH, C, N and metal abundance patterns of cave guano spatially and temporally (with depth) along a W-E transect in Malaysia and Palawan from five remote cave sites, each housing large populations of bats and Aerodramus spp.(cave swiftlets). Guano deposits were rich in phosphate and/or sulphate minerals (e.g., gypsum, bassanite) with leucophosphite, spheniscidite, and variscite present in most profiles. Metal abundances measured from modern and ancient bat guano revealed high concentrations of transition metals relative to the local environment. Highly enriched metals, however, were associated with phosphate rather than sulphate minerals. Copper and Zn were enriched in all profiles, whereas other metals were associated with specific caves consistent with known local mineral resources. For example, Sn, Pb, and Rb were particularly enriched in Batu Cave, located in the Peninsular Malaysian granitic tin belt, whereas Ni and Cr were high in regions associated with ultramafic ophiolites and Ni-laterites found on Palawan.

The Pleistocene geoarchaeology and geochronology of Con Moong Cave, North Vietnam: Site formation processes and hominin activity in the humid tropics

“…The behaviour of phosphate in extreme redox environments is poorly understood (Heiberg et al, ; Roden & Edmonds, ; Rothe et al, ), and it is probable that these incongruous associations result from diachronous episodes of diagenetic change related to fluctuations in sedimentary hydrology and resulting shifts in redox and pH in the burial environment (cf. Wurster, Munksgaard, Zwart, & Bird, ). We suggest the gypsum crystals precipitated due to oxidation of reduced sulphide compounds during a shift to drier conditions, a process analogous to the genesis of acid sulphate soils (Mees & Stoops, ).…”

“…As guano continued to accumulate, an upper section formed a very wet but aerobic zone (LSU C) dated to 64.7 ± 5.5 ka (Figure c). LSU C is dominated by taranakite (Table ), a phosphate mineral product of clay weathering in very wet, acidic environments (Bird et al, ; Frost, Xi, Palmer, & Pogson, ; Onac & Vereş, ; Shahack‐Gross et al, ; Weiner, Goldberg, & Bar‐Yosef, ; Wurster et al, ). Erosive contacts and sorting of fines correspond with macroscopically observed flame and load structures, which are features indicative of episodic mass movements of water‐saturated sediment (Bird et al, ; Dykes, ; Gilbertson et al, ).…”

A Late Holocene environmental history of a bat guano deposit from Romania: an isotopic, pollen and microcharcoal study

“…insect chitin fragments (<1 mm), along with fungi filaments. Finally, the bottom 26 cm consisted of black "rock guano" (Wurster et al, 2015), a drier, more compact material. Two sections of the core, at 96e103 cm and 125e147 cm, respectively, contained dispersed phosphate (brushite and hydroxylapatite) nodules resulted from the transformation of limestone fragments fallen into the guano mound.…”

Contribuição Mineralógica Para O Estudo De Relevância De Cavernas Ferríferas Da Serra Norte, Carajás-Pa

“…Esses últimos estando presentes em decorrência à presença de esfeniscidita e leucofosfita, respectivamente. O aporte de P 2 O 5 , bem como de NH 4 e K 2 O, para a formação dos espeleotemas fosfáticos, está relacionado à ocorrência de guano nas cavernas ferríferas, uma vez que as rochas hospedeiras das cavernas são empobrecidas nesses elementos (Forti, 2001;Wurster, Munksgaard, Zwart, & Bird, 2015). Em contrapartida, os elevados teores de Fe 2 O 3 são herdados das rochas encaixantes das cavernas, as quais são representadas por crosta laterítica e/ou saprólito de jaspilito do Grupo Grão Pará.…”

“…A saída do grupo OH -e da NH 3 -resulta no colapso total da estrutura e consequentemente sua completa amorfização. A saída da molécula de NH 3 -, associada aos outros dados da pesquisa, revelaram a presença de esfeniscidita, a qual foi reportada pela primeira vez por Sauro et al (2014), seguido por Wurster et al (2015), porém em caverna quatzítica e em cavernas carbonáticas, respectivamente;…”