Role of anthropogenic sulfuric and nitric acids in carbonate weathering and associated carbon sink budget in a karst catchment (Guohua), southwestern China

•Hydrochemical and δ13CDIC data with high spatial resolution were obtained.•Carbonate weathering is enhanced by anthropogenic acids under base flow condition.•Reduction of karst carbon sink flux by sulfuric and nitric acids is considerable.•Increase of carbonate weathering rate by sulfuric and nitric acids is significant.