Many groups of spatially correlated organisms have spatial
distributions that correspond to modelled processes. A total of
63% of the OEUs from the 2013 data set have a spatial profile that is
similar (distance less than 0.25) to one or more of the
biogeochemical processes simulated in the model (Supplementary
Fig. 8) and some of these OEU–process pairings are supported by
the previously reported ecosystem functions of one or more of the
OTUs in the OEU (Supplementary Table 6). This spatial alignment
between OEUs and modelled processes suggests that the growth of
organisms in those OEUs is dependent on the energy provided by
those processes. Because these OEUs are made up of OTUs that are
spatially correlated, taxonomically diverse and spatially aligned with
modelled biogeochemical processes, it may be that these OEUs are
consortia of organisms in syntrophic relationships (Fig. 4).
Not all taxa corresponding to a modelled process have the same
metabolism. There are other explanations for the properties of
the spatially correlated groups. Aside from consortia, they may