Table 2.

Summary of the ROI analysis of NanoSIMS ¹³C label distribution images

	Sulfidic pulse	24-h oxic + oxic pulse	Dead control	Natural carbon control
Microzooid symbiont	3.05 ***	1.07	1.07	1.06
	(2.69–3.28)	(1.07–1.07)	(1.06–1.07)	(1.06–1.06)
	n = 141	n = 50	n = 50	n = 50
Stalk symbiont	2.51	–	–	–
	(2.36–2.68)	–	–	–
	n = 150	–	–	–
Total symbiont	2.68 a	1.07 b	1.07 b	1.06 b
	(2.45–3.04)	(1.07–1.07)	(1.06–1.07)	(1.06–1.06)
	n = 291	n = 50	n = 50	n = 50
Microzooid host	1.15 ***	1.07	1.07	1.06
	(1.13–1.16)	(1.07–1.07)	(1.06–1.07)	(1.06–1.06)
	n = 100	n = 50	n = 50	n = 50
Stalk host	1.10	–	–	–
	(1.10–1.11)	–	–	–
	n = 50	–	–	–
Total host	1.13 a	1.07 b	1.07 b	1.06 b
	(1.11–1.15)	(1.07–1.07)	(1.06–1.07)	(1.06–1.06)
	n = 150	n = 50	n = 50	n = 50

For the sulfidic pulse and the 24-h oxic + oxic pulse, as well as for the two control experiments, the median of the ¹³C isotope fraction (¹³C/(¹²C + ¹³C), given in at%) is shown together with the interquartile range of the individual data points (Q25-Q75). (n) refers to the number of replicates analyzed within each treatment. For the symbiont, one replicate is one ROI drawn around one individual symbiont. For the host, the replicates are randomly selected ROIs within host cytoplasm. The Scheffe test (alpha = 0.05) was used to compare the ¹³C label content in the symbiont and host after the different treatments. The result of the Scheffe test is given with lowercase letters “a” and “b”, letters shared in common between groups indicate no significant difference. The Wilcoxon–Mann–Whitney test was performed to compare the microzooid and stalk area after the sulfidic pulse for both symbiont and host ¹³C enrichment.The results of this test is shown with asterisks.

***p  < 0.001