Dr. Jeffrey Krause

Diatoms are important because:

• Their cumulative global contribution to primary production is similar to that of the rain forests 
• They are important players in the oceanic cycles of Carbon, Nitrogen, and Silicon
• The sinking of diatom silica, and their associated organic matter, is a major component of the "Biological Pump"
• The production and cycling of diatom silica plays a fundamental role in regulating the exchange of CO₂ between the ocean and atmosphere 

Marine cyanobacteria and Silicon?

Recently, I have also worked on examining the role of picocyanobacteria in the global Silicon cycle, specifically those from the genus Synechococcus.  Photosynthetic cyanobacteria, primarily from the genre Prochlorococcus and Synechococcus, are the most abundant photosynthetic organisms on earth and generally the most abundant members of the phytoplankton community. Recently, our Nature Geoscience paper demonstrates that laboratory cultures and field cells (from eastern equatorial Pacific and Sargasso Sea) of Synechococcus accumulate elemental Silicon and we suggest that "picocyanobacteria may exert a previously unrecognized influence on the oceanic silicon cycle, especially in nutrient-poor waters."  A collaboration of scientists at Stony Brook University, Bigelow Laboratory for Ocean Sciences, UCSB and DISL, are currently funded by the National Science Foundation to examine the variability in Silicon quotas for cultured clones and field cells of Synechococcus and quantify their potential contribution to the rate which silica is produced in the open ocean (work with the Bermuda Atlantic Time-series Study program). 

Baines, S.B., Twining, B.S., Brzezinski, M.A., Krause, J.W., Vogt, S., Assael, D., McDaniel, H. 2012. Significant silicon accumulation by marine picocyanobacteria. Nature Geoscience 5, 886-891. doi: 10.1038/ngeo1641

Krause, J.W., Brzezinski, M.A., Villareal, T.A., Wilson, C. 2012. Increased kinetic efficiency for silicic acid uptake as a driver of summer diatom blooms in the North Pacific subtropical gyre. Limnology and Oceanography 57 (4), 1084–1098. doi:10.4319/lo.2012.57.4.1084

Villareal, T.A., Brown, C.G., Brzezinski, M.A., Krause, J.W., Wilson, C. 2012. Summer Diatom Blooms in the North Pacific Subtropical Gyre: 2008–2009. PLoS ONE 7: e33109. doi:10.1371/journal.pone.0033109

Brzezinski, M.A., Krause, J.W., Church, M.J., Karl, D.M., Li, B., Jones, J.L., Updyke, B. 2011. The annual silica cycle of the north Pacific subtropical gyre. Deep-Sea Research I 58, 988-1001. doi:10.1016/j.dsr.2011.08.001

Krause, J.W., Brzezinski, M.A., Jones, J.L. 2011. Application of low-level beta counting of 32Si for the measurement of silica production rates in aquatic environments. Marine Chemistry 127, 40-47. doi:10.1016/j.marchem.2011.07.001

Krause, J.W., Nelson, D.M., Brzezinski, M.A., 2011. Biogenic silica production and diatoms’ estimated contribution to primary production and nitrate uptake in the eastern equatorial Pacific Ocean. Deep-Sea Research II 58 (3-4), 434-448. doi:10.1016/j.dsr2.2010.08.010

Brzezinski, M.A., Baines, S.B., Balch, W.M., Beucher, C.P., Chai, F., Dugdale, R.C., Krause, J.W., Landry, M.R., Marchi, A., Measures, C.I., Nelson, D.M., Parker, A.E., Poulton, A.J., Selph, K.E., Strutton, P.G., Taylor, A.G., Twining, B.S., 2011. Co-limitation of diatoms by iron and silicic acid in the equatorial Pacific. Deep-Sea Research II 58 (3-4), 493-511. doi:10.1016/j.dsr2.2010.08.005

Demarest, M.S., Brzezinski, M.A., Nelson, D.M., Krause, J.W., Jones, J.L., Beucher, C., 2011. Net biogenic silica production and nitrate regeneration determine the strength of the silica pump in the Eastern Equatorial Pacific. Deep-Sea Research II 58 (3-4), 462-476. doi:10.1016/j.dsr2.2010.08.007

Krause, J.W., Brzezinski, M.A., Landry, M.R., Baines, S.B., Nelson, D.M., Selph, K.E., Taylor, A.G., Twining, B.S. 2010. The effects of biogenic silica detritus, zooplankton grazing, and diatom size structure on Si-cycling in the euphotic zone of the eastern equatorial Pacific. Limnology & Oceanography 55 (6), 2608-2622, doi:10.4319/lo2010.55.6.2608

Krause, J.W., Nelson, D.M., Lomas, M.W., 2010. Production, dissolution, accumulation, and potential export of biogenic silica in a Sargasso Sea mode-water eddy. Limnology & Oceanography 55 (2), 569-579, doi: 10.4319/lo.2010.55.2.0569

Current Lab Personnel: