Lake Michigan is one of the largest lakes in the world and the second largest of the North American Great Lakes by volume. Over the last two decades, the lake has witnessed significant ecological changes due to proliferation of invasive quagga mussels into its deeper offshore regions. The impact of these changes on the labile dissolved organic matter pool available for bacterial consumption and the relative importance of terre...

Summary Because bacterioplankton production rates do not vary strongly across vast expanses of the ocean, it is unclear how variability in community structure corresponds with functional variability in the open ocean. We surveyed community transcript functional profiles at eight locations in the open ocean, in both the light and in the dark, using the genomic subsystems approach, to understand variability in gene expression pa...

Summary Coastal ocean bacterioplankton control the flow of dissolved organic carbon (DOC) from terrestrial and oceanic sources into the marine food web, and regulate the release of inorganic carbon to atmospheric and offshore reservoirs. While the fate of the chemically complex coastal DOC reservoir has long been recognized as a critical feature of the global carbon budget, it has been problematic to identify both the compound...

Summary Metatranscriptomic analyses of microbial assemblages ( Cyanobacteria contributed a greater percentage of the transcripts (54% of annotated sequences) than expected based on abundance (35% of cell counts and 21% 16S rRNA of libraries), and may represent the most actively transcribing cells in this surface ocean community in both the day and night. Major heterotrophic taxa contributing to the community transcriptome incl...