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Dr. Jeffrey Krause

Senior Marine Scientist, Dauphin Island Sea Lab

Assistant Professor, Department of Marine Sciences

University of South Alabama      

Ph.D.  2008, College of Oceanic & Atmospheric Sciences, Oregon State University

jkrause@disl.org

Phytoplankton Ecology Laboratory

Research Interests:
I am interested in how phytoplankton (microscopic algae) cycle nutrients within the upper ocean where light penetrates.  My research focuses on the ecology of diatoms, a group of phytoplankton.  Diatoms have a characteristic shell made of amorphous silica (SiO2-nH2O), which is more dense than the seawater they live (i.e. diatoms sink).  They have a global distribution in both marine and freshwater environments and can occur in very high numerical abundances. 

 

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 genra Prochlorococcus and Synechoccocus, 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 Synechoccocus 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 Synechoccocus 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). 

 

Ten Representative Peer-review Publications:

Google Scholar Profile Page (http://scholar.google.com/citations?hl=en&user=Ax6slFUAAAAJ)

Baines, S.B., Twining, B.S., Brzezinski, M.A., Krause, J.W., Vogt, S., Assael, D., McDaniel, H.  2012.  Significant silicon accumulation by marine picocyanobacteriaNature 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 gyreLimnology and Oceanography 57 (4), 1084-1098.  doi:10.4319/lo.2012.57.4.1084

 

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 environmentsMarine 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 OceanDeep-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

 

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 PacificLimnology & 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 eddyLimnology & Oceanography 55 (2), 569-579, doi: 10.4319/lo.2010.55.2.0569

 

Krause, J.W., Lomas, M.W., Nelson, D.M.  2009.  Biogenic silica at the Bermuda Atlantic Time series Study site in the Sargasso Sea: Temporal changes and their inferred controls based on a 15-year recordGlobal Biogeochemical Cycles 23, GB3004, doi:10.1029/2008GB003236

 

Krause, J.W., Nelson, D.M., Lomas, M.W.  2009.  Biogeochemical responses to late-winter storms in the Sargasso Sea.  II. Increased rates of biogenic silica production and export. Deep-Sea Research I 56 (6), 861-874, doi:10.1016/j.dsr.2009.01.002

 

Lomas, M.W., Lipschultz, F., Nelson, D.M., Krause, J.W., Bates, N.R.  2009.  Biogeochemical responses to late-winterstorms in the Sargasso Sea.  I. Pulses of primary and new productionDeep-Sea Research I 56 (6), 843-860, doi:10.1016/j.dsr.2008.09.002

 

Current Funded Research Projects:

National Science Foundation:  Biological Field Stations & Marine Labs.  Acquisition of a Laser Ablation Inductively Coupled Plasma Mass Spectrometer to Support Marine Science Research and Education in the Northern Gulf of Mexico.” 

 

 National Science Foundation:  Biological Oceanography. “Group-Specific Diatom Silica Production in a Coastal Upwelling System.” 

 

National Science Foundation: Biological Oceanography. “Collaborative Research:  Understanding the role of picocyanobacteria in the marine silicate cycle.”   

 

 

Current Lab Personnel:

Eric Lachenmyer, M.S. (Lab Manager/Technician)

Ashley Larson (Intern)

Israel Marquez (M.S. student, University of South Alabama)

Heather McNair (Ph.D. student, University of California Santa Barbara)

 

Courses:

Physiology and ecology of marine microalgae (Graduate, University of South Alabama)

Introduction to Oceanography (Undergraduate/Graduate, Dauphin Island Sea Lab)

 

 

 

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