In this study we added bacterial loops to existing food web matrices. We examined the influence of these modifications on indirect connectivity by performing a power series of n on the adjacency matrices.  We also calculated dominant eigenvalues.  The dominant eigenvalues are interpreted as evidence of strongly connected components which lead to pathway proliferation.  As a control we randomly add equal numbers of connections in 100 randomizations per web.

Results/Conclusions

Addition of microbial loops dramatically increased connectivity, pathway proliferation, and dominant eigenvalues. For example, in the Benguela matrix the addition of microbial loops increased the dominant eigenvalue from 3.0 to 8.9. The 100 randomizations in which an an equal number of random connections were added produced a median dominant eigenvalue of 7.3.   We believe that this is powerful evidence that bacteria can dramatically increase connectivity in ecosystems.