Smithsonian NMNH The Plant Press: New Faces

From Plant Press, Vol. 25, No. 3, July 2022 https://nmnh.typepad.com/the_plant_press/new-faces/

Savannah Mapes,

a graduate student in dinoflagellate research, visited the Botany Department on 21-23 June 2022, to work on Dr. Maria Faust’s legacy material. Mapes is a fourth year PhD student at the Virginia Institute of Marine Science. She is studying the dynamics of harmful algal blooming (HAB) species in the lower Chesapeake Bay collecting data for the development of enhanced monitoring and mitigation strategies. She is also working on characterizing a local toxin-producing and bioluminescent HAB species, Alexandrium monilatum, describing its life cycle and using molecular techniques to investigate differences between strains. Mapes originally contacted Rose Gulledge for mentorship on a fellowship grant in December 2020. She then planned a visit to Botany and MSC to peruse Faust’s research material and other work-related documents, reprints, and library. Once finally here (she had to wait 1.5 years due to Covid restrictions), she found a treasure trove of HAB and dinoflagellate material from identification guides, teaching notes (complete with sketches), posters, photographs, SEM images, slides, and field notes. Faust’s taxonomic reviews, monographs and learning guides are essential reading for the HAB student; they are heavily used in the classroom as well as in the lab. Mapes’ future plans include continuing her career in scientific research on phytoplankton and creating a summer program for early career marine biology students to learn about the importance of phytoplankton and the marine environment through hands-on, field- and lab-based learning experiences.

2020 Winner of the FlowCam Student Equipment Grant for Graduate Students: Savannah Mapes

https://blog.fluidimaging.com/blog/announcing-the-2020-winner-of-the-flowcam-student-equipment-grant-for-graduate-students-savannah-mapes

Posted by: Savannah Judge

Today we are excited to announce the recipient of this year’s Aquatic FlowCam Research Equipment and Travel grant for graduate students. This grant provides students and professors with access to a FlowCam at their lab for the fall semester, as well as financial support to present their work involving the FlowCam at a North American conference (remotely, if needed).

This is the first year we have offered this program since 2016, and we received an astonishing 26 applications across both undergraduate and graduate categories and were amazed by the quality of research put forward by each applicant.

This year’s graduate award goes to Savannah Mapes, a graduate student at the Virginia Institute of Marine Science (VIMS) who is studying harmful algal blooming (HAB) species in the lower Chesapeake Bay with Dr. Kimberly Reece. She will be using the FlowCam 8100 to study HAB dynamics in the York River/lower Chesapeake Bay while also studying the life cycle of Alexandrium monilatum, a local toxin-producing HAB species, in the lab. Prior to VIMS, Savannah earned her bachelor’s degree in Marine Biology at Texas A&M Galveston, where she studied the effects of oil spills on phytoplankton in the Gulf of Mexico and completed an REU at Mote Marine Lab where she studied a potential parasitic biocontrol for Karenia brevis (“Florida red tide”).

Please join us in congratulating Savannah and VIMS!

Core metabolism plasticity in phytoplankton: Response of Dunaliella tertiolecta to oil exposure

Manoj Kamalanathan, Savannah Mapes, Alexandra Prouse, Patricia Faulkner, Nathan Hagen Klobusnik, Jessica Hillhouse, David Hala, Antonietta Quigg

Abstract: Human alterations to the marine environment such as an oil spill can induce oxidative stress in phytoplankton. Exposure to oil has been shown to be lethal to most phytoplankton species, but some are able to survive and grow at unaffected or reduced growth rates, which appears to be independent of the class and phylum of the phytoplankton and their ability to consume components of oil heterotrophically. The goal of this article is to test the role of core metabolism plasticity in the oil-resisting ability of phytoplankton. Experiments were performed on the oil- resistant chlorophyte, Dunaliella tertiolecta, in control and water accommodated fractions of oil, with and without metabolic inhibitors targeting the core metabolic pathways. We observed that inhibiting pathways such as photosynthetic electron transport (PET) and pentose-phosphate pathway were lethal; however, inhibition of pathways such as mitochondrial electron transport and cyclic electron transport caused growth to be arrested. Pathways such as photorespiration and Kreb's cycle appear to play a critical role in the oil-tolerating ability of D. tertiolecta. Analysis of photo-physiology revealed reduced PET under inhibition of photorespiration but not Kreb's cycle. Further studies showed enhanced flux through Kreb's cycle suggesting increased energy production and photorespiration counteract oxidative stress. Lastly, reduced extracellular carbohydrate secretion under oil exposure indicated carbon and energy conservation, which together with enhanced flux through Kreb's cycle played a major role in the survival of D. tertiolecta under oil exposure by meeting the additional energy demands. Overall, we present data that suggest the role of phenotypic plasticity of multiple core metabolic pathways in accounting for the oxidative stress tolerating ability of certain phytoplankton species.

Fig: Heat map of chlorophyll a fluorescence depicting the growth response of Dunaliella tertiolecta in response to various metabolic inhibitors at 300 μM concentrations in the Control and WAF treatment (n = 3).