The fourth edition of this bestselling text has been rigorously updated to reflect major new discoveries and concepts since 2019. This new edition reflects important new findings in marine microbiology revealed by development of high-throughput sequencing, meta-omics, and single-cell technologies, and the ability to analyse and interpret large datasets. Furthermore, it presents major new insights into topics such as the physiology of planktonic microbes and their role in ocean processes; t...