Table S2.

Summary of lateral fluxes of carbon and the flow-weighted yields used to calculate the total carbon flux by HUC

HUC	No. of DIC sites	Total DIC flux, TgC⋅y−1	Total DIC flux error, TgC⋅y−1	Weighted DIC yield, gC⋅m2⋅y−1	DIC yield as % of TC yield	No. of TOC sites	Total TOC flux, TgC⋅y−1	Total TOC flux error, TgC⋅y−1	Weighted TOC yield, gC⋅m2⋅y−1	TOC yield as % of TC yield
01	13	0.441	0.035	2.783	40.0	10	0.661	0.077	4.172	60.0
02	21	1.233	0.083	4.289	66.2	21	0.631	0.071	2.194	33.8
03	42	1.584	0.069	2.270	43.1	38	2.089	0.221	2.993	56.9
04	32	4.904	0.019	10.630	74.7	19	1.657	0.058	3.592	25.3
05	1	4.382	0.045	10.382	77.3	1	1.285	0.025	3.045	22.7
06	1	0.629	0.008	5.933	81.1	1	0.147	0.003	1.387	18.9
07	1	5.081	0.074	10.331	80.3	1	1.250	0.053	2.542	19.7
08	3	0.763	0.011	2.908	41.0	3	1.098	0.034	4.186	59.0
09	3	0.246	0.091	1.597	55.1	3	0.200	0.046	1.303	44.9
10	1	2.892	0.019	2.184	75.6	1	0.932	0.019	0.704	24.4
11	3	1.750	0.036	2.728	71.3	3	0.704	0.020	1.097	28.7
12	12	0.914	0.185	1.967	66.6	12	0.458	0.095	0.986	33.4
13	3	0.012	0.003	0.034	79.4	1	0.003	0.001	0.009	20.6
14	1	0.524	0.001	1.784	73.7	1	0.187	0.010	0.638	26.3
15	14	0.034	0.002	0.094	56.7	5	0.026	0.007	0.072	43.3
16	58	0.697	0.009	1.896	89.0	30	0.086	0.011	0.234	11.0
17 Coast	2	0.803	0.040	4.800	84.0	2	0.153	0.045	0.912	16.0
17 Dry	25	1.699	0.054	2.983	77.2	17	0.503	0.094	0.883	22.8
18 Dry	11	1.197	0.298	2.995	74.9	10	0.401	0.063	1.004	25.1