Table 2. Sulfur isotopic composition (δ³⁴S, mean ± SEM) in per mille [‰] of bulk S, insoluble sulfur compounds (S⁰), organic sulfur, and sulfate in different Zostera marina tissues in situ; n = 6.

Tissue	δ34S [‰]
	bulk S	S0	organic sulfur	sulfate
Leaf	1.71 ± 0.86A,a	1 ± 0.98A,a	3.02 ± 1.25A,a	2.15 ± 0.55A,a
Rhizome	0.61 ± 1AB,a	-2.17 ± 0.82B,a	5.01 ± 1.38C,a	2.14 ± 0.27A,a
Root	-10.24 ± 0.76A,b	-9.11 ± 0.96A,b	-11.27 ± 1.4A,b	0.89 ± 0.73B,a

Note that S⁰ was assessed from insoluble sulfur compounds. Capital letters indicate significant differences between compounds within a tissue; lower case letters indicate significant differences between the tissue types in a specific compound. ANOVA and post hoc Tukey’s test; p < 0.05.