Mini sediment columns and two-dimensional sediment flow-through microcosms: Versatile experimental systems for studying biodegradation of organic contaminants in groundwater ecosystems.

Groundwater ecosystems are our most important source for drinking water supply. The increasing pressure to our groundwater reservoirs from anthropogenic contamination is a major threat not only to the ecosystem but also to human health. Microbial transformation of quantitatively important organic contaminants, such as petroleum hydrocarbons, in aquifers is an ecosystem service of ecological as well as economic importance. However, key controls and limitations of biodegradation in situ are still poorly understood. Facing the limited accessibility of the subsurface, the complex structural heterogeneity, and the hidden temporal physical–chemical and biotic dynamics, bench-top experimental systems are necessary tools for a systematic and controlled investigation of key variables in contaminant removal processes at appropriate micro- and meso-scales. Here, we introduce mini sediment columns and two-dimensional sediment flow-through microcosms as complementary versatile experimental systems that offer a high degree of simplification, experimental control, and replication