Table 1.

List of samples analyzed

			Picoplankton sorted samples				Nanoplankton sorted samples
Transect	Station	Depth (m)	Sample code	Sorted cells #	18S sequence #	nifH sequence #	Sample code	Sorted cells #	18S sequence #	nifH sequence #
0	6	45	1p	7651	19,466	137,117	1n	4845	95,054	163
			2p	7343	107,644	113,897	2n	3258	45,111	143
	19	0	3p	1005	134,873	92,500	3n	898	131,031	116
	21	0	5p	793	112,590	25,341	5n	660	24,696	77,360
	26	0	7p	907	22,348	26,969	7n	856	40,829	7667
1	81	140	9p	3181	44,610	53	9n	1235	19,193	34
			10p	3278	47,390	6241	10n	1232	53,230	36
	85	110	11p	16,312	31,899	10,201	11n	1615
	86	105	13p	6366	59,626	11,954	13n	1007	46,001	21,316
	87	105	15p	6189	78,390	1033	15n	622	22,468	2678
2	96	5	120p	1150	76,182	23,147	120n	75	70,455	93
		30	121p	1737	71,785	23,706	121n	218	52,401	26,838
		50	122p	853	37,364	11,045	122n	234	78,740	15,543
	98	5	125p	3086	55,179	21,461	125n	1300	27,381	14,331
		50	126p	1217	30,406	10,140	126n	782	65,714	16,929
		85	127p	3420			127n	226	60,610	11,493
	101	5	140p	500	46,569	12,301	140n	366	48,126	25,286
		60	141p	1046	64,221	10,428	141n	485	30,081	21,302
		110	142p	641	89,797	17,156	142n	159	85,219	11,753
	106	5	155p	355	50,782	66,172	155n	18	54,162	20,674
		60	156p	1800	43,917	16,093	156n	300	55,065	14,447
		100	157p	6910	51,848	15,204	157n	1152	29,078	15,532
	114	5	165p	728	48,514	39,918	165n	226	50,732	14,706
		60	166p	660	62,897	28,107	166n	578	53,412	24,442
		80	167p	722	49,934	13,971	167n	390	31,424	20,616
	Bloom	0	tri01p	1002	36,576	7772	tri01n	194	14,162	11,792
			tri02p	744	46,889	17,259	tri02n	206	23,906	16,934
			tri03p	600	55,630	15,152	tri03n	218	34,892	21,523

Samples corresponding to sorted photosynthetic picoeukaryote populations are labeled with p and those corresponding to sorted photosynthetic nanoeukaryote populations are labeled with n. Samples with <2000 sequences (in italics) were not considered in the analysis