Controls on Diatom Biogeography in the Ocean

Abstract

Monitoring Massive Microbial Dispersal Quantifying the relative influence of present-day environmental conditions and geological history on the spatial distribution of species represents a major challenge in microbial ecology. Ecological approaches to distinguish between these two biogeographic controls are limited by environmental variability both in space and through time (see the Perspective by Patterson ). Using a 1.5-million-year fossil record of marine diatoms, Cermeño and Falkowski (p. 1539 ) show that, even at the largest (global) spatial scale, the dispersal of marine diatoms is not very limited. Environmental factors are the primary control shaping the global biogeography of marine diatom morphospecies. Thermophilic microorganisms are routinely detected in permanently cold environments from deep sea sediments to polar soils. Hubert et al. (p. 1541 ) provide a quantitative analysis of a potentially large-scale dispersion of thermophilic bacteria in the ocean. Approximately 10 8 thermophilic spores are deposited each year on every square meter of Arctic sediment.