ABSTRACT
Marine water constitutes the largest contiguous habitat on the globe, occupying more than 70% of Earth’s surface with an average depth of 4 km. Life in this environment is, in contrast to the most terrestrial habitats, dominated by microorganisms, both with regard to metabolism and biomass. These microbes accomplish many unique steps of the biogeochemical cycles, and they also signify a huge and dynamic source of genetic variability (Karl, 2007). Therefore, this environment represents one of the most signicant, but still least understood, microbial environments on Earth. In addition, marine microbial communities were among the rst microbial communities to be studied using metagenomic approaches (DeLong, 2005), and over the last years, there have been several studies reporting exploration of microorganisms within marine water and sediments (e.g., Venter et al., 2004; Rusch et al., 2007). Unlocking the secrets of marine microbes requires the application of an innite array of techniques and approaches. Classical microbiology deals with cultivation and characterization of organisms. Merely a tiny portion of the microorganisms we know exist. The vast majority of them (95%–99%) remain “unseen” in pure culture (Amann et al., 1995). For instance, using molecular biology and genomics to establish their community structure and metabolic capabilities (Amann et al., 1995), well-established molecular techniques like uorescence in situ hybridization (FISH) (Amann et al., 1990) have proven crucial
CONTENTS
32.1 Introduction ........................................................................................................................685 32.2 Metagenomics Technology to Analyze Structure and Function of Marine
Microbial Communities .................................................................................................... 687 32.2.1 Sequence-Based Screening ................................................................................... 687 32.2.2 Function-Based Screening ....................................................................................688
32.3 Advances in Marine Microbial Metagenomics of Biocatalysts ................................... 689 32.4 Advances in Marine Microbial Metagenomics of Gene Clusters ............................... 691 32.5 Advances in Marine Microbial Metagenomics of Biogeocycling ............................... 694 32.6 Advances in Marine Microbial Metagenomics of Natural Products ......................... 696 32.7 Advances in Marine Methanobacterial Metagenomics ............................................... 697 32.8 Concluding Remarks ......................................................................................................... 698 Acknowledgment ........................................................................................................................ 698 References ..................................................................................................................................... 699
