Abstract：
The growth rate contributes to setting the ecological success of a microbe and to determining its contribution to food web dynamics and biogeochemical processes in the oceans. This presentation will review progress in understanding growth rates of bacteria and phytoplankton in the oceans along with recent work in Delaware waters on photoheterotrophs and SAR11 bacteria, the most abundant clade of bacteria in marine systems. Extensive data sets on production and biomass can be used to estimate growth rates for the entire community as well as to explore control of these rates by bottom-up and top-down factors. More recent data from microautoradiography and rRNA levels indicate that growth rates of most heterotrophic bacteria are low (<0.1 per day) while only a few taxa can have 10-fold faster rates. These data along with genomic and metagenomic data are also used to explore trophic strategies of SAR11 and other bacteria in the oceans. While the methods are imperfect and more data are needed as always, the available data can be used to set limits on growth rates and thus on the time scale for changes in the composition and structure of microbial communities.
Dr. Kirchman's homepage: http://www.ceoe.udel.edu/our-people/profiles/kirchman
