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 and around the globe, we investigate these ecophysiological responses on different levels (from gene expression to ecosystem function) and in many ecosystems (Gulf of Mexico, tropical oligotrophic regions, Southern Ocean and coastal upwelling regions). We hope that our work will inform many different groups of researchers. For example:
  • Our work on nitrogen isotopes in the Southern Ocean aims to inform the interpretation of paleo proxies on the strength of the biological carbon pump during glacial and interglacial cycles.
  • Our work on N2 fixing organisms will inform biogeochemical modelers on current and projected future productivity of our oceans
  • The work on marine productivity will inform ecologists, physiologists and numerical modelers on processes affecting the base of the marine food web.
  • We further hope that our work on the toxic dinoflaggelate Karenia brevis, a Gulf of Mexico red tide organism, will inform decision makers and ecosystem managers to better understand and predict the socio-economic impact of this organism in the current and future ocean.
        

News from the lab 

  • Our Nature communications artice is out! 11/22: Phosphate limitation intensifies negative effects of ocean acidification on globally important nitrogen fixing cyanobacterium.  https://www.nature.com
  • New publication 11/22: Application-specific optimal model weighting of global climate models: A red tide example.https://www.sciencedirect.com/
  • 10/22: We are hosting a new graduate student from the FSUCML (marinelab), Benton from Dr. Schantz lab and his UROP student in our lab to work on Karenia brevis related research.
  • 09/22: Three new UROP students, Angelique, Ava and Ben accepted our offer to join the lab! They will be working with Ana and Jared either on mixotrophy in Karenia brevis or on our Southern Ocean nitrate isotope project.
  • 09/22: A new student intern, Jacqueline (Penny), started in the lab and will be working with Maggie on Antarctic diatoms.
  • New publication 09/22: Taxon-specific phytoplankton growth, nutrient utilization and light limitation in the oligotrophic Gulf of Mexico.  https://academic.oup.com
  • 08/22: Our new graduate student Margaret (Maggie) Baker arrived!
  • New publication  05/22: Inorganic carbon acquisition by aquatic primary producers. https://onlinelibrary.wiley.com
  • New publication 05/22: Earth system models for regional environmental management of red tide: Prospects and limitations of current generation models and next generation development. https://link.springer.com
  • New student led publication 02/22: Effects of spectral light quality on the growth, productivity, and elemental ratios in differently pigmented marine phytoplankton species. https://link.springer.com
  • New publication 01/22: Prescreening-based subset selection for improving predictions of Earth system models with application to regional prediction of red tide https://www.frontiersin.org
     

The Lab at FSU 

The Kranz lab is located on 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 between the different groups located here. We have designated lab spaces for culture work, chemical handling, a dark room for microscopy and light sensitive analysis, a wal- in cold room and a make-shift clean room (until the clean room is fully functional).

some pictures of our lab space here

We regularly conduct field research - usually on research vessels.      

some pictures of recent cruises can be found 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 socioeconomical significance as they affect water quality and fisheries. Consequently, understanding the current distribution and productivity of phytoplankton in ecological important ocean basins, and assessing 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 intensit, CO2 concentrations and/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, photosynthetic efficiency, the modes of carbon and nutrient acquisition and isotope fractionation are investigated on multiple cellular levels. Laboratory studies with isolated monoclonal cultures and research cruises increase our process understanding of how and why phytoplankton, found in the different regions of the World's oceans, respond to environmental stressors.

The Team

We all work together to create an inclusive group. We embrace the responsibiility of providing and nurturing an affirming climate that supports and celebrates individual identities across a broad spectrum while ensuring equitable treatment. Our lab has a zero tolerance policy towards discrimination of any kind! Everyone is welcome!

PI

Dr. Sven Kranz

 

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PhD. student

Jared Rose

 

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Master's student

Margaret Baker

 

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Master's student

Thomas "Miles" Hampton

 

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Lab-tech

Person 4

Ana Boesel

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Undergraduate students

Angelique Kremer (UROP 2022/2023)

Project: Mixotrophy in K.brevis   

Ava Trail (UROP 2022/2023)

Project:Osmotrophy in K.brevis   

Jacqueline Carr (Penny) (DIS/Intern 2022/2023)

Project: Antarctic Diatoms - light and iron effects   

Benjamin Alboucrek (UROP 2022/2023)

Project: Antarctic Diatoms - light and iron effects   

Guests

Benton Jaco; FSUCML

Project: K.brevis : allelopathy   

about Benton

Anthony (UROP 2022/2023)

Project under Benton: K.brevis : allelopathy   

Dr. Grisel Fierros; FAMU

 

about: I am a young scientist, my research has been focused on environmental microbiology, and heavy metal resistance in microorganisms. My interest in science has led me to research in different organisms such as Nicotiana tobacco cells cultures, Bacillus megaterium, Microbacterium liquefaciens, heavy-metal resistant fungi, heavy metal resistant bacteria, aquatic viruses, and protists, and most recently in Halobacteriovorax, a predatory bacterium from the oceans.

Grisell's research

Project: NSF award 1948758   

Jackson Powell; FSU-Bio

about Jackson
  

about: I am studying the potential for adaptation in marine invertebrates with complex life cycles. I take quantitative genetics approaches to estimate additive genetic variance, selection, and reaction norm traits in larval and adult life history stages. In particular, I use breeding designs and environmental manipulations to accomplish my goals.

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 2018-2021)

L. Morales (2018)

T. Fletcher (2018-2019)

A. Silva (2018-2019)

B. Gerad (2018-2019)

Nolan Hartz (UROP (2019-2020)

Chase Collier (2022)

Graduate Alumni

Dr. Bercel

Tristyn Bercel

Tristyn graduated in 2021 and is curently Post-Doc at the Mote-Laboratory in Sarasota Florida https://mote.org/staff/member/tristyn-bercel

 

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Our Funded Projects 

Thanks NSF and FWRI! 

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

 https://www.nsf.gov/awardsearch/showAward?AWD_ID=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 

 https://www.nsf.gov/awardsearch/showAward?AWD_ID=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

https://www.nsf.gov/awardsearch/showAward?AWD_ID=1851347&HistoricalAwards=false

Excellence in Research: Assessing the Control by Multiple Micropredators on Bacterial Communities in Estuarine Environments and Characterization of Prey Lysis Products Resulting from each Predator 

We hypothesize that environmental factors significantly influence how mortality in bacterial populations is partitioned among the micropredators. To test this hypothesis we are (1) investigating the interactions amongst the micropredators, (2) examining the molecular-level composition and dynamics of dissolved organic matter as the result of the different mortality processes by the NMR/ FT-ICR mass spectrometry (MS) hybrid approach, and (3) modeling these tri-trophic dynamics. Intellectual Merit: Results from this research will define a new mechanistic understanding of mortality dynamics that influence the microbial loop and oceanic biogeochemical cycles.      

 Award Abstract # 1948758 

 https://www.nsf.gov/awardsearch/showAward?AWD_ID=1948758

other smaller projects funded or conducted in the lab

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 

Purchase of a Gas Chromatography - Mass Spectrometer System to Develop a Multidisciplinary User Facility for Environmental Research

funding received via FSU-EIEG -Equipment and Infrastructure Enhancement Grant 2022  

FSUCML real-time, continuous seawater monitoring system

funding received via FSU-EIEG -Equipment and Infrastructure Enhancement Grant 2022  

Culturing

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

K. brevis research supported by FWRI

Reseach is conducted on multiple unanswered question regarding K.brevis bloom persistence under different enviornmental conditions

This research has been supported by the Florida Fish and Wildlife Consortium Research Institute. Undergraduate researchers from FSU have and will work on specific task assignments under this research agreement  

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

We collaborate with the CCE-LTER program to measure ecosystem productivity as part of the CCE 2016, 2017 and 2018 process cruises.Future cruises in 2023-2027 are funded.