The Johnson Lab presented recent research at the Ocean Sciences Meeting 2014 in Honolulu. One poster highlighted data from recent POWOW cruises. Specifically, it was an analysis of the primary production data collected in January and July 2013. The title of the poster was “Magnitude and Regulation of Prochlorococcus and Synechococcus Primary Production in the Northern Pacific Ocean” and its abstract was the following:
The cyanobacteria Prochlorococcus and Synechococcus are the most abundant photosynthetic microbes in the open ocean. As such they likely are responsible for a large fraction of the primary production in these areas, but the magnitude of this contribution is poorly constrained. To address this gap, here we report C-14 based primary production for two size fractions: >0.8 μm and <0.8 μm, the latter representing most of the two cyanobacteria populations. Measurements were made in the Northern Pacific Ocean during January and July 2013 and include multiple transects spanning several environmental gradients. Winter production levels, which were dominated (62% ± 15) by the large size class, were lower than those in the summer. Conversely, 60% ± 8 of the summer production is associated with the cyanobacteria size fraction. The main driver of primary production in the winter was temperature, whereas the patterns in the summer respond to temperature and nitrate concentration. These results demonstrate that cyanobacteria are major drivers of the carbon cycle in these ecosystems, but their photosynthetic rates are regulated by a multiple environmental variables suggesting a complex response to future climate change.
Additional presentations included “Unlocking the potential of smartphones to enable ocean science education” and “Ecological processes structuring Prochlorococcus communities” both by Zackary Johnson.
