Table 2.

Results of linear mixed-effects models testing the fixed effects of (a) time and quadratic term of time (time²) and (b) time, time², voyage route and the interaction term between time and voyage route (time × voyage route) for CP and total PP associated with invertebrate and diatom assemblages in control tanks during trans-Atlantic and trans-Pacific voyages separately and pooled together, respectively. (c) Follow-up models were conducted to distinguish the effects of biogeographic region and voyage length associated with voyage route. These additional models standardized voyage length for Pacific and Atlantic route to the first 9 days only. Time and time² were included as fixed effects in (a) models for dinoflagellates. Dashes indicate non-significant variables that were removed from the final optimal models.

	invertebrates				diatoms				dinoflagellates
	d.f.	β	t	p	d.f.	β	t	p	d.f.	β	t	p
(a) CP (Atlantic)
time	—	—	—	—	23	−0.7	−2.9	<0.01	—	—	—	—
time2	—	—	—	—	—	—	—	—	20	−0.2	−3.8	<0.01
total PP (Atlantic)
time	27	−5778.6	−3.3	<0.01	—	—	—	—	—	—	—	—
time2	—	—	—	—	—	—	—	—	—	—	—	—
CP (Pacific)
time	23	−3.4	−3.4	<0.01	24	−1.3	−4.7	<0.01	n.a.	n.a.	n.a.	n.a.
time2	23	0.1	2.3	0.03	24	0.1	3.7	<0.01	n.a.	n.a.	n.a.	n.a.
total PP (Pacific)
time	23	−23 825.3	−4.7	<0.01	—	—	—	—	n.a.	n.a.	n.a.	n.a.
time2	23	1119.0	3.9	<0.01	—	—	—	—	n.a.	n.a.	n.a.	n.a.
(b) CP (full voyages)
time	50	−3.1	−4.6	<0.01	44	−1.1	−4.8	<0.01	n.a.	n.a.	n.a.	n.a.
time2	50	0.11	3.0	<0.01	44	0.03	3.5	<0.01	n.a.	n.a.	n.a.	n.a.
voyage route	50	−13.8	−5.9	<0.01	—	—	—		n.a.	n.a.	n.a.	n.a.
time × voyage route	50	1.9	4.9	<0.01	—	—	—		n.a.	n.a.	n.a.	n.a.
total PP (full voyages)
time	50	−23 901.3	−5.0	<0.01	—	—	—	—	n.a.	n.a.	n.a.	n.a.
time2	50	1107.23	4.2	<0.01	—	—	—	—	n.a.	n.a.	n.a.	n.a.
voyage route	—	—	—	—	50	37 752.9	5.0	<0.01	n.a.	n.a.	n.a.	n.a.
time × voyage route	50	6489.2	2.4	0.02	—	—	—	—	n.a.	n.a.	n.a.	n.a.
(c) CP (first 9 days)
time	—	—	—		31	−0.8	−4.5	<0.01	n.a.	n.a.	n.a.	n.a.
time2	—	—	—		—	—	—		n.a.	n.a.	n.a.	n.a.
voyage route	2	−7.1	−5.8	0.03	—	—	—		n.a.	n.a.	n.a.	n.a.
time × voyage route	—	—	—		—	—	—		n.a.	n.a.	n.a.	n.a.
total PP (first 9 days)
time	41	−32 839.7	−4.6	<0.01	—	—	—	—	n.a.	n.a.	n.a.	n.a.
time2	41	2295.5	2.8	<0.01	—	—	—		n.a.	n.a.	n.a.	n.a.
voyage route	—	—	—	—	35	29 853.6	2.8	<0.01	n.a.	n.a.	n.a.	n.a.
time × voyage route	—	—	—		—	—	—	—	n.a.	n.a.	n.a.	n.a.