Old methane fuels modern river food web

Dominant ecological paradigms provide theoretical frameworks for two basal sources of carbon to riverine food webs: carbon fixed by algae and submerged macrophytes (autochthonous) and carbon fixed by terrestrial vascular plants that enter aquatic ecosystems as litter (allochthonous). An additional, less studied, pathway for carbon to enter rivers is as methane that is produced in small quantities via methanogenesis by anaerobic methanogenic archaea. Because rivers are generally well oxygenated, methane is not often recognised as a substantial contributor to riverine carbon budgets. However, methane may also enter rivers via natural gas macro–seeps where underground deposits connect to the surface via fissures and fractures. We explored the contribution of methane from natural gas macro–seeps to food webs by comparing δ13C values of animals and their foods from reaches rich in dissolved methane with reaches where methane concentrations were at background levels. Animals collected fr..., , # Old methane fuels modern river food web

Dataset DOI: [10.5061/dryad.wh70rxx0d](10.5061/dryad.wh70rxx0d)

## Description of the data and file structure

Here we provide the data we used to complete our stable isotope analyses. Please refer to the manuscript methods for details of our analyses. We provide 4 csv files that include data for river discharge, d13C values of sources and consumers, and trophic discrimination factors.

**1) combined_methane_descrimination.csv**: trophic discrimination factors used in the MixSiar model for each animal taxon.

* Consumer: identity of each animal taxa

- Source: potential sources of carbon

* Meand13C: mean delta 13C values

- SDd13C: standard deviation of delta 13C values

* Mean15N: mean delta 15N values

- SDd15N: standard deviation of delta 15N values

**2) Discharge_DS_Chinchilla.csv**: daily river discharge in the Condamine River

* Date: date of observation (dd/mm/yy)

- Q: discharge (ML/day)

**3) methane_consumers.csv**: delta 13C value...,