Cattle Pasture (IMAGE) Universität Bayreuth Caption Leakage of iron-rich groundwater in a cattle pasture. The red colour comes from a mixture of oxidised iron and carbon compounds, which are highly reactive redox phases. Credit Photo: Stefan Peiffer. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.