About the lab

In our lab we study phytoplankton ecology and biogeochemistry. We are specifically interested in how different phytoplankton groups respond to environmental perturbations such as changes in CO2, light intensity and nutrient availability. My students and I aim to not only characterize the responses of phytoplankton to a multitude of environmental factors, but also to understand the underlying processes of the measured responses, such as photosynthetic pathways, carbon acquisition processes and protein regulation. In collaboration with my colleagues at FSU, within the US an around the globe, we investigate these ecophysiological responses on many levels from gene expression to ecosystem function) and in many ecosystems (Gulf of Mexico tropical oligotrophic regions, Southern Ocean and costal upwelling).        

The Lab at FSU 

The Kranz lab is located at the main campus in Tallahassee. Our lab is on the 5th floor of the new EOA building and has an open concept which will enhance interaction of graduate and undergraduate students. We also have designated lab spaces for culture handling, chemical handing and microscopy.      

some pictures of our lab space here

Our mission

Despite their microscopic size, phytoplankton are responsible for about half of the global primary production. This diverse group of organisms is an integral component of the global biosphere, driving biogeochemical cycles of important elements while exporting large amounts of carbon to deep waters and sediments. In coastal regions, these organisms also have a socioeconomically significance as they affect water quality and fisheries. Consequently, understanding the current distribution and productivity of phytoplankton in ecological important ocean basins, and assess how and why the phytoplankton community may respond to perturbations driven by environmental change, constitutes a major challenge in aquatic research. We aim to understand community composition and productivity of phytoplankton in the world's oceans. For this, we study phytoplankton communities and monoclonal cultures under different environmental scenarios such as changes in temperature, light intensity and CO2 concentrations or availability of iron. A suite of in vivo assays based on standard and cutting-edge techniques provide a mechanistic understanding of the observed responses. Processes such as productivity, cellular composition, photosynthesis and its efficiency, as well as the modes of carbon acquisition are investigated on multiple cellular level. Laboratory studies with isolated monoclonal cultures can increase our process understanding of how and why the most important phytoplankton species found in the different regions of the world's oceans respond to a future oceanic environment.

The Team

PI, graduate students and undergraduate students working here hand in hand


Dr. Sven Kranz




Ph.D. candidate

Tristyn Bercel



Master's student

Jared Rose





Person 4

Undergrduate Students



Angela Hodapp (working remotely on meta-data collection for  project #1939994)

We are always looking for motivated and interested students to support our graduate students and conduct DIS (directed individual studies)! 

Alumni -Undergrduate Students

Daniel Owen (2015)

K. Ferguson (2015)

P Knight (2016)

J Boronek (2016)

Y. Danyuk (2016-2017) Honors thesis

T. Mogavero (2017-2018)

Ariana Goldstein (UROP - 2017-2018)

Angela Hodap (UROP 217-2018; RA 2018-2020)

L. Morales (2018)

T. Fletcher (2018-2019)

A. Silva (2018-2019)

B. Gerad (2018-2019)

Nolan Hartz (UROP (2019-2020)

Our Funded Projects 

Thanks NSF! 

Collaborative Proposal:Quantifying the effects of variable light and iron on the nitrate assimilation isotope effect of phytoplankton 

This project will test the hypothesis that enhanced light and/or iron stress on phytoplankton change the isotopic ratios of water column nitrate-in specific ways. A combination of laboratory culture and field experiments in the Southern Ocean will be conducted.

Award Abstract #1850925



Multi-Scale Exploration of Nutrient Cycles and its Socio-Economic Impacts in Coastal Areas 

This project will explore the Energy Exascale Earth System Model (E3SM) for simulating nutrient fluxes from a terrestrial system to an ocean system and for linking E3SM-simulated nutrient fluxes to red tide occurrence in support of socio-economic impact assessment.     

 Award Abstract #1939994 



 Collaborative Research: Mesoscale variability in nitrogen sources and food-web dynamics supporting larval southern bluefin tuna in the eastern Indian Ocean

This project investigates how mesoscale variability in new production, food-web structure and trophic fluxes affects feeding and growth conditions for Southern Bluefin Tuna larvae in the Indian Ocean.

Award Abstract #1851347



   other smaller projects conducted in the lab to improve phytoplankton cultivation in the age of climate change

Development and testing a new LED-based lighting system to assess the response of phytoplankton to light variations

funding received via the FSU-CRC planning grant 

Measuring Net community production, gross production and carbon aquisition in the California Current Upwelling Sysyem

We were invited by CCE-LTER program to measure ecosystem productivity as part of the CCE 2016, 2017 and 2018 process cruises. In 2016, Seaver Wang and Nicolas Cassar (Duke University) contributed to  the cruise. In 2017, our group with Seaver Wang and Nicolas Cassar, and in 2018 our group with Thomas Kelly/Michale Stukl (FSUcontributed to the chaacerization of net community productivity in the California upwelling current.    


 We currently culture multiple species of phytoplankton in the laboratory.

 Thalassiosira weissflogii (diatom); Syncechococcus (cyanobacterium), Prochlorochoccus (cyanobacterium), Fragilariopsis cylindrus (Antarctic diatom), Thalassiosira antarctica (Antarctic diatom), Emiliania huxleyi (Coccolithophore), Karenia brevis (dinoflagellate) 

 Undergraduate students are welcome to work on small projects to investigate the effect on various envionmental factors on any of those species