Channelling of basal resources and use of allochthonous marine carbon by soil arthropods of the Wadden Sea salt marsh

Salt marshes are located between the marine and terrestrial systems. Because they form as sediment accumulates, they comprise a gradient of shore height with differing inundation frequencies and associated abiotic soil conditions. Along this gradient, both autochthonous vascular plant resources and allochthonous marine algal or detrital resources are available, with the availability of both varying with season and salt marsh zone. However, little is known about the importance of either resource for the soil animal food web. We investigated both spatial and temporal resource use of the soil macro- and mesofauna of the salt marsh using neutral lipid fatty acids (NLFAs). Generally, irrespective of season and zone the soil animal food web relied on carbon originating from autochthonous vascular plants and associated bacteria and fungi, with the role of bacteria generally exceeding that of fungi. However, the channelling of fungal resources consistently peaked in October, whereas seasonal ch..., Samples were taken along five transects spanning across the USM, LSM and PZ on the island of Spiekeroog (Wadden Sea National Park, Germany; 53˚45’2”- 53˚47’1”N, 7˚40’0”-7˚49’1”E) in April (spring), July (summer) and October (autumn) 2019. Within each transect, one soil core of 20 cm diameter was taken per zone and separated into two layers (0–5 and 5–10 cm depth). Cores were stored in plastic containers and kept at ambient temperature until soil fauna extraction at the University of Göttingen. Soil fauna was extracted using heat (Kempson et al. 1963); animals were extracted into a 1:1 mixture of Glycol and water. Once extracted, the animals were filtered through 45 µm gauze, flushed with water and placed into 70 % ethanol for storage at -20°C. Animals were identified under a stereomicroscope, macrofauna was identified to species, whereas mesofauna species were grouped to higher taxonomic units to gain sufficient material for lipid extraction. To achieve sufficient fauna material soil ho..., Program required: Microsoft Excel, or similar