Skip to main content
U.S. flag

An official website of the United States government

Benjamin James Kramer, PhD

My research background primarily focuses on how climate change and eutrophication impact harmful algae in freshwater ecosystems. This has included determining how elevated temperatures as well as carbon dioxide levels, in tandem with nitrogen availability, impact the growth, toxin synthesis, and gene expression of cyanobacteria and other phytoplankton, particularly within the Great Lakes. 

The term "harmful algae" encompasses a broad, highly diverse number of organisms in marine and freshwater environments that significantly impact ecosystems and devastate human health and industries. As we are in an ever-changing world, it is critical we understand how aquatic ecosystems will respond to climate change and other anthropogenic stressors, particularly when it comes to primary production. My dissertation and postdoctoral work involved extensive research into determining the importance of carbon dioxide on harmful freshwater cyanobacteria and the greater phytoplankton community. Freshwater carbonate chemistry is poorly understood relative to that of marine systems, even in the Great Lakes, and it is critical we fill those gaps in our understanding in order to better diagnose how phytoplankton and other primary producers such as harmful algae will respond. Thus, my work has involved analytical techniques such as the measurement of N2-fixation, dissolved inorganic carbon levels, and cyanotoxins as well as molecular techniques (metagenomics, metatranscriptomics, and metabolomics). All of this work has been done using traditional and novel experimental as well as field methods.

Professional Experience

  • Biologist (USGS Great Lakes Science Center; Aug 2024 - present)

  • Postdoctoral researcher (University of Minnesota Duluth; Jul 2022 - Aug 2024)

  • Graduate assistant (SUNY Stony Brook; Jul 2015 - Jun 2022)

  • Assistant professor (Suffolk Community College; Sep. 2017 - Dec. 2021)

  • Graduate assistant (UNC Wilmington; Aug. 2012 - May 2015)

Education and Certifications

  • Ph.D. 2022 SUNY Stony Book 

  • M.Sc. 2015 UNC Wilmington

  • B.S. 2010 Georgia Institute of Technology

Affiliations and Memberships*

  • International Association of Great Lakes Research (IAGLR), 2024 - present

  • Association for the Sciences of Limnology and Oceanography (ASLO), 2024 - present

Honors and Awards

  • Chair for 2023 Gordon Research Seminar on Phycotoxins and Mycotoxins

  • Recipient for 2nd-best student presentation award (2019 US HAB Symposium)

Abstracts and Presentations

  • Carbonate chemistry and its potential impacts on phytoplankton in the Great Lakes (ASLO 2024)

  • The genome characteristics and distribution of Dolichospermum circinale in the Great Lakes (IAGLR 2024)

  • Carbonate chemistry and the N2–fixing potential of the Great Lakes (2024 CIGLR All Partners Meeting)

  • Understanding the impacts of climate change and eutrophication on cyanobacteria and the toxins they produce (2024 USDA Agricultural Research Services Seminar)

  • Inorganic carbonate chemistry of the Great Lakes (2024 USGS NOAA Workshop)

  • The effects of climate change processes and eutrophication on bloom-forming, toxin-producing, N2-fixing cyanobacteria (2023 GRC Mycotoxins and Phycotoxins)

  • Great Lakes acidification and harmful algal blooms (2023 NOAA OAP Community Meeting)

  • The effects of climate change and eutrophication on Dolichospermum: A harmful, diazotrophic cyanobacterial genus (2022 US Harmful Algal Symposium)

  • The effects of climate change and eutrophication on Dolichospermum: A harmful, diazotrophic cyanobacterial genus (2022 University of Minnesota Duluth Department of Biology Seminar)

  • Elevated CO2 significantly increases N2 fixation, growth rates, and alters microcystin, anatoxin, and saxitoxin cell quotes in strains of the bloom-forming cyanobacteria, Dolichospermum (2019 US Harmful Algal Symposium)

  • Transcriptomic and physiological responses of Dolichospermum sp. 54, an anatoxin-producing cyanobacterium, to different nutrient regimes (2018 International Conference of Harmful Algae)

  • The interactive roles of nitrogen loading and warming in controlling microcystin production in Microcystis (2017 US Harmful Algal Symposium)

Science and Products

Publications by this scientist

Nitrogen limitation, toxin synthesis potential, and toxicity of cyanobacterial populations in Lake Okeechobee and the St. Lucie River Estuary, Florida, during the 2016 state of emergency event Nitrogen limitation, toxin synthesis potential, and toxicity of cyanobacterial populations in Lake Okeechobee and the St. Lucie River Estuary, Florida, during the 2016 state of emergency event

Lake Okeechobee, FL, USA, has been subjected to intensifying cyanobacterial blooms that can spread to the adjacent St. Lucie River and Estuary via natural and anthropogenically-induced flooding events. In July 2016, a large, toxic cyanobacterial bloom occurred in Lake Okeechobee and throughout the St. Lucie River and Estuary, leading Florida to declare a state of emergency. This study...
Authors
Benjamin J. Kramer, Timothy W. Davis, Kevin A. Meyer, Barry Rosen, Jennifer Goleski, Gene Oh, Christopher J. Gobler

Non-USGS Publications**

Kramer, B. J., Turk-Kubo, K., Zehr, J. P., & Gobler, C. J. (2024). Intensification of harmful cyanobacterial blooms in a eutrophic, temperate lake caused by nitrogen, temperature, and CO2. Science of The Total Environment, 915, 169885. https://doi.org/10.1016/j.scitotenv.2024.169885
Gobler, C. J., Di Cecco, G. J., Doherty, O. M., & Kramer, B. J. (2024). Decadal warming has intensified microcystis‐dominated cyanobacterial blooms in Lake Erie. Limnology and Oceanography Letters. https://doi.org/10.1002/lol2.10406
Kramer, B. J., & Gobler, C. J. (2023). Simulated heat waves promote the growth but suppress the N2 fixation rates of Dolichospermum spp. and cyanobacterial communities in Temperate Lakes. Ecological Indicators, 147, 109983. https://doi.org/10.1016/j.ecolind.2023.109983
Kramer, B. J., Hem, R., & Gobler, C. J. (2022). Elevated CO2 significantly increases N2 fixation, growth rates, and alters microcystin, anatoxin, and saxitoxin cell quotas in strains of the bloom-forming cyanobacteria, dolichospermum. Harmful Algae, 120, 102354. https://doi.org/10.1016/j.hal.2022.102354
Kramer, B. J., Jankowiak, J. G., Nanjappa, D., Harke, M. J., & Gobler, C. J. (2022). Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, dolichospermum. Frontiers in Microbiology, 13. https://doi.org/10.3389/fmicb.2022.955032
Jankowiak, J., Hattenrath‐Lehmann, T., Kramer, B. J., Ladds, M., & Gobler, C. J. (2019). Deciphering the effects of nitrogen, phosphorus, and temperature on cyanobacterial bloom intensification, diversity, and toxicity in western Lake Erie. Limnology and Oceanography, 64(3), 1347–1370. https://doi.org/10.1002/lno.11120
J. Kramer, B., J. Bourdelais, A., Kitchen, S. A., & Taylor, A. R. (2018). Uptake and localization of fluorescently‐labeled karenia brevis metabolites in non‐toxic marine microbial taxa. Journal of Phycology, 55(1), 47–59. https://doi.org/10.1111/jpy.12787
Chia, M. A., Kramer, B. J., Jankowiak, J. G., Bittencourt-Oliveira, M. do, & Gobler, C. J. (2019). The individual and combined effects of the cyanotoxins, anatoxin-A and microcystin-LR, on the growth, toxin production, and nitrogen fixation of Prokaryotic and eukaryotic algae. Toxins, 11(1), 43. https://doi.org/10.3390/toxins11010043

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

Cladophora biomass and supporting data collected in the Great Lakes, 2024 (ver. 1.1, July 2025) Cladophora biomass and supporting data collected in the Great Lakes, 2024 (ver. 1.1, July 2025)

This dataset records Cladophora and associated benthic algae, collectively the Cladophora community or submerged aquatic vegetation (SAV), biomass collected during the growing season of 2024 at stations located along the U.S. shoreline of Lakes Michigan, Huron, Erie, and Ontario. It also records a variety of supporting data collected at Cladophora measurement stations. These supporting...
By
Great Lakes Science Center
Researcher wearing a life vest sitting on a boat gunwale.
Benjamin Kramer on Lake Michigan in 2025
Benjamin Kramer on Lake Michigan in 2025
Researcher wearing a life vest sitting on a boat gunwale.

Benjamin Kramer on Lake Michigan in 2025

Benjamin Kramer on Lake Michigan in 2025

Dr. Benjamin Kramer is shown on a small research vessel in July 2025 near Sleeping Bear Dunes in Leelanau County, MI collecting benthic mats on Good Harbor Reef as part of USGS's UMESC SWIM (Spawning Whitefish Invasive Mussels) project. Photo Credi: Megan Lewan, USGS

By
Great Lakes Science Center
Researcher wearing a life vest sitting on a boat gunwale.

Benjamin Kramer on Lake Michigan in 2025

Benjamin Kramer on Lake Michigan in 2025

Dr. Benjamin Kramer is shown on a small research vessel in July 2025 near Sleeping Bear Dunes in Leelanau County, MI collecting benthic mats on Good Harbor Reef as part of USGS's UMESC SWIM (Spawning Whitefish Invasive Mussels) project. Photo Credi: Megan Lewan, USGS

By
Great Lakes Science Center

Science and Products

Publications by this scientist

Nitrogen limitation, toxin synthesis potential, and toxicity of cyanobacterial populations in Lake Okeechobee and the St. Lucie River Estuary, Florida, during the 2016 state of emergency event Nitrogen limitation, toxin synthesis potential, and toxicity of cyanobacterial populations in Lake Okeechobee and the St. Lucie River Estuary, Florida, during the 2016 state of emergency event

Lake Okeechobee, FL, USA, has been subjected to intensifying cyanobacterial blooms that can spread to the adjacent St. Lucie River and Estuary via natural and anthropogenically-induced flooding events. In July 2016, a large, toxic cyanobacterial bloom occurred in Lake Okeechobee and throughout the St. Lucie River and Estuary, leading Florida to declare a state of emergency. This study...
Authors
Benjamin J. Kramer, Timothy W. Davis, Kevin A. Meyer, Barry Rosen, Jennifer Goleski, Gene Oh, Christopher J. Gobler

Non-USGS Publications**

Kramer, B. J., Turk-Kubo, K., Zehr, J. P., & Gobler, C. J. (2024). Intensification of harmful cyanobacterial blooms in a eutrophic, temperate lake caused by nitrogen, temperature, and CO2. Science of The Total Environment, 915, 169885. https://doi.org/10.1016/j.scitotenv.2024.169885
Gobler, C. J., Di Cecco, G. J., Doherty, O. M., & Kramer, B. J. (2024). Decadal warming has intensified microcystis‐dominated cyanobacterial blooms in Lake Erie. Limnology and Oceanography Letters. https://doi.org/10.1002/lol2.10406
Kramer, B. J., & Gobler, C. J. (2023). Simulated heat waves promote the growth but suppress the N2 fixation rates of Dolichospermum spp. and cyanobacterial communities in Temperate Lakes. Ecological Indicators, 147, 109983. https://doi.org/10.1016/j.ecolind.2023.109983
Kramer, B. J., Hem, R., & Gobler, C. J. (2022). Elevated CO2 significantly increases N2 fixation, growth rates, and alters microcystin, anatoxin, and saxitoxin cell quotas in strains of the bloom-forming cyanobacteria, dolichospermum. Harmful Algae, 120, 102354. https://doi.org/10.1016/j.hal.2022.102354
Kramer, B. J., Jankowiak, J. G., Nanjappa, D., Harke, M. J., & Gobler, C. J. (2022). Nitrogen and phosphorus significantly alter growth, nitrogen fixation, anatoxin-a content, and the transcriptome of the bloom-forming cyanobacterium, dolichospermum. Frontiers in Microbiology, 13. https://doi.org/10.3389/fmicb.2022.955032
Jankowiak, J., Hattenrath‐Lehmann, T., Kramer, B. J., Ladds, M., & Gobler, C. J. (2019). Deciphering the effects of nitrogen, phosphorus, and temperature on cyanobacterial bloom intensification, diversity, and toxicity in western Lake Erie. Limnology and Oceanography, 64(3), 1347–1370. https://doi.org/10.1002/lno.11120
J. Kramer, B., J. Bourdelais, A., Kitchen, S. A., & Taylor, A. R. (2018). Uptake and localization of fluorescently‐labeled karenia brevis metabolites in non‐toxic marine microbial taxa. Journal of Phycology, 55(1), 47–59. https://doi.org/10.1111/jpy.12787
Chia, M. A., Kramer, B. J., Jankowiak, J. G., Bittencourt-Oliveira, M. do, & Gobler, C. J. (2019). The individual and combined effects of the cyanotoxins, anatoxin-A and microcystin-LR, on the growth, toxin production, and nitrogen fixation of Prokaryotic and eukaryotic algae. Toxins, 11(1), 43. https://doi.org/10.3390/toxins11010043

**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.

Cladophora biomass and supporting data collected in the Great Lakes, 2024 (ver. 1.1, July 2025) Cladophora biomass and supporting data collected in the Great Lakes, 2024 (ver. 1.1, July 2025)

This dataset records Cladophora and associated benthic algae, collectively the Cladophora community or submerged aquatic vegetation (SAV), biomass collected during the growing season of 2024 at stations located along the U.S. shoreline of Lakes Michigan, Huron, Erie, and Ontario. It also records a variety of supporting data collected at Cladophora measurement stations. These supporting...
By
Great Lakes Science Center
Researcher wearing a life vest sitting on a boat gunwale.
Benjamin Kramer on Lake Michigan in 2025
Benjamin Kramer on Lake Michigan in 2025
Researcher wearing a life vest sitting on a boat gunwale.

Benjamin Kramer on Lake Michigan in 2025

Benjamin Kramer on Lake Michigan in 2025

Dr. Benjamin Kramer is shown on a small research vessel in July 2025 near Sleeping Bear Dunes in Leelanau County, MI collecting benthic mats on Good Harbor Reef as part of USGS's UMESC SWIM (Spawning Whitefish Invasive Mussels) project. Photo Credi: Megan Lewan, USGS

By
Great Lakes Science Center
Researcher wearing a life vest sitting on a boat gunwale.

Benjamin Kramer on Lake Michigan in 2025

Benjamin Kramer on Lake Michigan in 2025

Dr. Benjamin Kramer is shown on a small research vessel in July 2025 near Sleeping Bear Dunes in Leelanau County, MI collecting benthic mats on Good Harbor Reef as part of USGS's UMESC SWIM (Spawning Whitefish Invasive Mussels) project. Photo Credi: Megan Lewan, USGS

By
Great Lakes Science Center

*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government

Was this page helpful?