Jeffrey Johansen, PhD

Expertise: Cyanobacterial and diatom taxonomy and molecular systematics, Using algae as bioindicators of water quality, Anthropogenic climate change, aquatic resources and ecology.

Dr. Johansen is an internationally recognized researcher in cyanobacterial taxonomy and systematics, with collaborators in Czech Republic, Mexico, India, Russia, and Brazil. He is an associate editor for two academic journals. Dr. Johansen has been recognized by John Carroll University as a recipient of the Distinguished Faculty Award, received an honorary doctoral degree from the University of South Bohemia in Czech Republic, and the PSA Award of Excellence for sustained scholarly contributions and impact in the field of Phycology. He regularly teaches workshops on cyanobacterial and algal taxonomy in the USA and abroad. He also has hosted a number of regional, national, and international conferences. He has brought over $4,100,000 in external research grants during his tenure at JCU. Dr. Johansen has mentored numerous graduate and undergraduate researchers during his more than 30 years of service at John Carroll, and invites students interested in research to work in his lab. Many of his students present at national meetings, and have gone on to additional graduate education after leaving JCU. His current research funding supports a study of soil cyanobacteria and eukaryotic algae of San Nicolas Island, California.

Research Interests

Cyanobacterial taxonomy and molecular systematics, diatom taxonomy and ecology, water quality, biological soil crust floristics and ecology  

Teaching Interests

Anthropogenic climate change, algae as bioindicators, aquatic resources.

Recent Courses

• BL 137 – Climate Change in North America
• BL 159/BL 160 – Biodiversity BL 331 – Global Climate Change
• BL 445 – Aquatic Resources
• BL 447 – Algae as Bioindicators  

Recent Publications

Kumar, N., Saraf, A., Pal, S., Mishra, D., Singh, P. & Johansen, J.R. 2023.Circumscription of Fulbrightiella gen. nov. and Sherwoodiella gen. nov., two novel genera in the Calotrichaceae (Nostocales, Cyanobacteria). Journal of Phycology 59. DOI: 10.1111/jpy.13297.

Ruka, A.T., Johansen, J.R., Leps, J., Loken, Z.J., Schuler, M., Mttes, B., Yates, E. & Relyea, R.A. 2022. Seasonal diatom community responses to development and climate change in Lake George, an oligotrophic lake in the Adirondack Mountains. Hydrobiologia 849: 2761-2780.

Baldarelli, L.M., Pietrasiak, N., Osorio-Santos, K. & Johansen, J.R. 2022. Mojavia aguilerae and M. dolomitestris – two new Nostocaceae (Cyanobacteria) species from the Americas. Journal of Phycology 58: 502- 516.

Gaysina, L.A., Johansen, J.R., Saraf, A., Allaguvatova, R.Z., Pal, S. & Singh, P. 2022. Roholtiella volcanica sp. nov., a new species of Cyanobacteria from Kamchatkan Volcanic Soils. Diversity 14, 620. https://doi.org/10.3390/d14080620.

Brown, A.O., Romanis, C.S., Dvořák, P., Foss, A.J., Gibson, Q.A., Villanueva, C.D., Durden, W.N., Garvey, A.D., Jenkins, P., Hašler, P., Johansen, J.R., Neilan, B.A. & Casamatta, D.A. 2021. A new species of cryptic cyanobacteria isolated from the epidermis of a bottlenose dolphin and as a bioaerosol. Phycologia 60: 603-618.

Johansen, J.R., González-Resendiz, L., Escobar-Sánchez, V., Segal- Kischinevzky, C., Martínez-Yerena, J., Hernández-Sánchez, J., Hernández- Pérez, G. & León-Tejera, H. 2021. When will taxonomic saturation be achieved? A case study in Nunduva and Kyrtuthrix (Rivulariaceae, Cyanobacteria). Journal of Phycology 57: 1699–1720.

Ward, R. D., Stajich, J.E., Johansen, J.R., Huntemann, M., Clum, A., Foster, B. Foster, B., Roux, S. Palaniappan, K., Varghese, N., Mukherjee, S., Reddy, T.B.K., Daum, C., Copeland, A., Chen, I.-M.A., Ivanova, N. N., Kyprides, N. C., Shapiro, N., Eloe-Fadrosh, E. A. & Pietrasiak, N. 2021. Metagenome sequencing to explore phylogenomics of terrestrial cyanobacteria. Microbiol. Resour. Announc. 10:e00258-21

Pietrasiak, N., Osorio-Santos, K., Lipson, D.L. & Johansen, J.R. 2021. Trichotorquatus gen. nov. – a new genus of soil cyanobacteria discovered from American drylands. Journal of Phycology 57: 886–902.

Komárek, J., Johansen, J.R., Šmarda, J. and Strunecký, O. 2020. Phylogeny and taxonomy of Synechococcus–like cyanobacteria. Fottea 20: 171-91.

Becerra-Absalón, I., Johansen, J.R., Osorio-Santos, K. & Montejano, G. 2020. Two new Oculatella (Oculatellaceae, Cyanobacteria) species in soil crusts from tropical semi–arid uplands of México. Fottea 20: 160–70.

Shalygin, S., Shalygina, R., Redkina, V.V., Gargas, C.B. & Johansen, J.R. 2020. Description of Stenomitos kolaenensis and S. hiloensis sp. nov. (Leptolyngbyaceae, Cyanobacteria) with an emendation of the genus. Phytotaxa 440 (2): 108–128.

Casamatta, D.A., Villanueva, C.D., Garvey, A.D., Stocks, H.S., Vaccarino, M., Dvořák, P., Hašler, P., & Johansen, J.R. 2020. Reptodigitus chapmanii (Nostocales, Hapalosiphonaceae) gen. nov.: a unique nostocalean (Cyanobacteria) genus based on a polyphasic approach. Journal of Phycology 56: 425-436.

Mesfin, M., Johansen, J.R., Pietrasiak, N. & Balderelli, L.M. 2020. Nostoc oromo sp. nov. (Nostocales, Cyanophyceae) from Ethiopia: a new species based on morphological and molecular evidence. Phytotaxa 433 (2): 81-93.

Pietrasiak, N., Osorio-Santos, K., Shalygin, S., Martin, M. P. & Johansen, J.R. 2019. When is a lineage a species? A case study in Myxacorys gen. nov. (Synechococcales: Cyanobacteria) with the description of two new species from the Americas. Journal of Phycology 55: 976-996.

González-Resendiz, L., Johansen, J.R., León-Tejera, H., Sanchéz, L., Segal- Kischinevsky, C., Escobar-Sánchez, V. & Morales, M. 2019. A bridge too far in naming species: a total evidence approach does not support recognition of four species in Desertifilum (Cyanobacteria). Journal of Phycology 55: 898- 911.

Mareš, J., Johansen, J.R., Hauer, T., Zima, J., Jr., Ventura, S., Cuzman, O., Tiribilli, B. & Kaštovský, J. 2019. Taxonomic resolution of the genus Cyanothece (Chroococcales, Cyanobacteria), with a treatment on Gloeothece and three new genera, Crocosphaera, Rippkaea, and Zehria. Journal of Phycology 55: 578-610.

Grants and Research Funding

Invasive Algae Survey to Benefit Rare and Endangered Species on Naval Outlying Field, San Nicolas Island. Naval Base Ventura County. Santa Barbara Botanical Garden $49,170. (2021)

Phylogenetic placement of unculturable cyanobacterial genera using single-cell sequencing techniques. Ministry of Education of the Czech Republic, (to University of South Bohemia). 1,617,000 CZK ($70,820 USD) (2019)

Phylogenetic establishment of cyanobacterial genera through multilocus analysis of the generitypes.  Czech Grant Agency (to University of South Bohemia). 9,301,000 CZK ($435,000 USD) (2014)

Biodiversity survey of freshwater algae of the Hawaiian Islands.  National Science Foundation.  $130,000 (2008)

Biodiversity of terrestrial cyanobacteria in the Atacama Desert, Chile.  National Science Foundation.  $400,000 (2008)

Assessing the condition of the Great Rivers using benthic and planktonic algal indicators.  U.S. Environmental Protection Agency.  $96,226 (2005)

Algal Biodiversity in the Great Smoky Mountains National Park.  National Science Foundation.  $88,494 (2003)

Polyphasic characterization and phylogenetic classification of the problematic form-genus Leptolyngbya (Cyanobacteria).  National Science Foundation.  $150,000 (2002)

Great Lakes Diatom Indicators in the Estuarine Environment Research Program.  US Environmental Protection Agency.  $213,334 (2000)