. 2014 Apr 21;111(19):7030–7035. doi: 10.1073/pnas.1404820111

Table 1.

Characteristics of empirical semivariograms for streamwater chemistry based on Euclidean, flow-connected, and flow-unconnected spatial relationships in the Hubbard Brook Valley

	Euclidean relationship			Flow-connected network relationship		Flow-unconnected network relationship
Solute	Type	Scale, m		Type	Scale, m	Type	Scale, m
H⁺	Single	2,300	—	Single	1,500	Nested	900	4,500
Ca²⁺	Nested	1,000	?	Single	1,800	Single	2,500	—
Mg²⁺	Nested	1,100	3,700	Single	1,700	Nested	2,600	?
Na⁺	Single	?	—	Nested	1,600	Nested	2,600	?
K⁺	Nested	1,200	5,400	Single	1,700	Single	1,800	—
	—	—	—	—	—	—	—	—
Al_m	Nested	700	3,400	Single	1,700	Nested	900	4,500
DSi	Nested	1,100	3,200	Single	1,800	Single	?	—
	Nested	2,600	?	Single	1,700	Nested	1,100	5,900
Cl⁻	Nested	500	3,600	Single	1,500	Nested	1,700	4,600
NO₃⁻	Single	3,600	—	—	—	Nested	1,100	?
	Nested	1,200	?	—	—	Single	2,100	—
DOC	Single	3,200	—	Single	1,500	Nested	800	5,200
DIC	Nested	1,100	?	Single	1,400	—	—	—
ANC	Nested	1,300	?	Single	1,900	Nested	500	2,600
SC	Nested	1,200	3,200	Single	1,600	Nested	1,800	5,300

Semivariogram type and range for each spatial relationship indicate nested-scale (i.e., multiple-scale) versus single-scale spatial structure and the distances over which spatial dependence is expressed, respectively. The dash symbol (—) indicates semivariograms (i) for which the type or range could not be determined because of low chemical concentrations or (ii) that are not applicable for the given type. An unknown range is indicated with a question mark (?) for solutes with semivariograms that appear to be nested beyond the maximum separation distance used for the analysis or for ranges that cannot easily be determined visually.