Science - USA (2021-10-29)

~14,400 km across groups at the surface. It is
also positively correlated to within-basin auto-
correlation (rP= 0.56,P= 10−^7 at the surface;
fig. S10C), which measures the tendency for
communities from the same oceanic basin to

be composed of the same assemblages (here-

after referred to as a“basin-based structure”),

and negatively correlated with latitudinal auto-

correlation (rP=−0.49,P= 10−^5 at the surface;

fig. S10E), which measures the tendency for

communities at the same latitude on both sides

of the equator to be composed of the same as-

semblages (hereafter referred to as a“latitude-

based structure”; see materials and methods).

Results are similar at the DCM, although less

596 29 OCTOBER 2021•VOL 374 ISSUE 6567 science.orgSCIENCE

–0.2

–0.1

0.0

0.1

0.2

–0.2 –0.1 0.0 0.1 0.2

30 100 700

Body size (μm)

Chordata

Diplonemida

Collodaria

Dinophyceae

Diversity (#OTUs)

100

1,000

70,000

Mamiellophyceae

Bacillariophyta

Weak biogeographic

structure

Biogeographic axis 1

Biogeographic axis 2

Large-scale,

basin-based biogeo.

Small-scale,latitude-based biogeo.

Strong biogeographic

structure

A

Diplonemida Dinophyceae

Collodaria

Chordata

Bacillariophyta

Mamiellophyceae

B

C

D E

F G

Fig. 2. Biogeographic heterogeneity across major eukaryotic plankton groups.
(A) Principal coordinates analysis of the biogeographic dissimilarity between 70
major plankton groups. Each dot corresponds to the projection of a group onto the
first two axes of variation; dot size varies with the group’s log diversity, and dot color
varies with its log mean body size. The 70 groups cover the full spectra of
biogeographies, from those with weak spatial structure (left) to those organized at

large spatial scale by oceanic basin (top right) or at smaller spatial scale and

according to latitude (bottom right). (BtoG) Surface biogeography of six

representative groups that are labeled in (A). Only the most prevalent assemblages

in each group are shown by using colors that are variations of the group’s color in

Fig. 1B; the remaining assemblages are left in gray. See fig. S5 for additional groups, and

see ( 31 ) for assemblage-by-assemblage representations of the same biogeographies.

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