Ecosystem metabolism is a key component driving organic carbon (OC) cycling in streams and rivers modulating the amount of carbon available to downstream ecosystems. The capacity of streams and rivers to store, mineralize, and export carbon is linked to flow regimes as hydrology dictates the delivery and downstream fluxes of terrestrial and aquatic OC. Worldwide, however, climate change is driving the alteration of stream flows with likely consequences to OC cycling. To quantify how changes in flow regime drive OC cycling, we estimated ecosystem metabolism (gross primary production (GPP) and ecosystem respiration (ER)) and OC spiraling metrics of 10 streams spanning a precipitation gradient across the coastal plains and piney woods ecoregions in Texas, USA. Across all sites, median GPP was low (> 1 g C m^-2 d^-1) and median ER fluxes ranged from 0.2 to 3.75 g C m^-2 d^-1 resulting in daily heterotrophy. The median turnover length (S_oc) of OC (distance OC travels before mineralization to CO₂) ranged from 8 to 184 km, peaking in streams falling in the middle of the precipitation gradient. The median OC mineralization velocity (v_f) increased across the precipitation gradient ranging from 0.03 – 0.34 m d^-1. While S_oc was within range of more productive rivers, v_f was 2 – 6-fold lower in comparison to streams with higher GPP. Despite low GPP however, these streams appear to be reactive regarding OC spiraling where mineralization rates may increase with increasing stream flows due to climate change scenarios.