Thermal Controls on Clogging‐Declogging Processes Within the Benthic Biolayer of Intermittent Streams

Benthic biolayers with abundant microbial activity below the sediment‐water interface significantly contribute to stream metabolism and bioclogging processes. Most research has focused on the lotic phase of intermittent streams, with limited attention to the impact of temperature on bioclogging in static pool‐aquifer systems. In this study, we combined column experiments with temperature‐dependent models of reactions, microbial growth, and bioclogging to investigate the thermal controls on clogging‐declogging processes within and below the benthic biolayer. Warmer temperatures (40°C) significantly alleviated bioclogging, resulting in a 12.8% reduction in porosity compared to the 30°C group. This declogging is primarily driven by two mechanisms: (a) increased temperatures inhibit microbial growth, compressing the spatial range of the benthic biolayer and limiting the vertical extent of the clogging layer induced by biofilm; (b) biogas formation and release are stimulated by higher temperatures, as evidenced by the denser gas voids observed in sediment profiles. Intense gas release may open up clogged layers and alter the microtopography at the bed surface. The model further indicated that the thickness of the benthic biolayer and clogging layer linearly decreases with temperature under mesotrophic and eutrophic conditions, while its impact in oligotrophic conditions is negligible. Therefore, temperature is a crucial factor regulating surface‐subsurface interactions and should be considered in water resource management in dry regions. These results are relevant in the context of climate change, where warmer temperatures expected in isolated pools are likely to make them greenhouse gas emission hotspots from intermittent streams in the future.