Marine Microorganisms, Biogeochemical Cycles, and Global Climate Change

Abstract

Summary: ? Marine microbes drive chemical reactions that contribute to Earth's habitability. ? Although molecular techniques are used to monitor oceanic microbial communities, collecting intermittent samples for laboratory analysis limits the usefulness of this approach. ? Instruments that collect and analyze microbes in situ can provide unprecedented resolution of biogeochemical cycles over large spatial and temporal scales. ? We should combine knowledge of key genes with new instruments to obtain time-series information on key marine microbial biogeochemical transformations. The oceans maintain critical ecosystems that, ultimately, determine the habitability of the planet. Moreover, unicellular eukaryotes, bacteria, and archaea are the most abundant organisms within those ecosystems and thus the dominant biomass within the oceans, situated at the base of the food chain that feeds macroscopic invertebrates, fish, and mammals. We are only beginning to uncover the extent of marine microbial genetic diversity and the complex roles that these microbes play in driving the biogeochemistry of global ocean ecosystems. Molecular biology, genomics, microscopy, mass spectrometry, and high-throughput cultivation are already providing useful information on the diversity and activities of marine microflora, including new biochemical pathways. However, in the face of global environmental change, we need to gain a deeper understanding of the distributions of marine microbes and their activities in maintaining ecosystem functions.