The project will use a combination of pyrosequencing and QPCR approaches to examine rRNA:rDNA ratios, BrdU incorporating cells, and transcript types and amounts in the metatranscriptome of Sargasso Sea surface water. Pyrosequencing (454) avoids amplification and cloning artifacts and it is cost effective. Preliminary analyses indicate that the sequence length of 454 reads and the proposed number of sequences are ideal for addressing the questions raised here. The investigators will also use Micro-FISH to examine incorporation of thymidine, leucine, and PO4. Samples will be collected twice yearly during the spring phytoplankton bloom when heterotrophic bacterial production is lowest and during the peak of bacterial production in summer.