Contrasting Estuarine Processing of Dissolved Organic Matter Derived From Natural and Human?Impacted Landscapes

The flux of terrigenous organic carbon through estuaries is an important and changing, yet poorly understood, component the global cycle. Using dissolved (DOC) fluorescence data from 13 British draining catchments with highly variable land uses, we show that use strongly influences fate DOC across ocean transition via its influence on composition lability constituent matter (DOM). In peatland-dominated catchments, was correlated biologically refractory “humic-like” material which tended to be conservatively transported along salinity gradient. contrast, there a weaker correlation between DOM components within high degree human impact, is, relatively larger percentage arable (sub)urban uses. These contain fraction bioavailable “protein-like” behaved nonconservatively, both removals additions occurring. general, peatland (?18%) have higher area-specific estuarine exports (>13 g C m?2 yr?1) compared those (?46%) uses (<2.1 yr?1). Our indicate these tend export, average, ?50% more coastal areas than they receive rivers due net anthropogenic derived inputs estuary.