Irena Kaczmarska

Research Professor
Flemington Rm. 210


Representative Publications (names of students and postdocs in bold):  


Villac, M.C., I. Kaczmarska & J.M. Ehrman. 2016. Diatoms from ship ballast sediments (with consideration of a few additional species of special interest). Diatom Monographs Vol. 18, Koeltz Botanical Books, Koenigstein, 566 pp.


Kaczmarska, I. & J.M. Ehrman. 2023. Parmalean and other siliceous nannofossils from the Oligocene Flysch Carpathians. Acta Palaeontologica Polonica 68: 441-456.

Kaczmarska, I., Ehrman, J.M. & Ashworth, M.P. 2022. Sexual reproduction and auxospore development in the diatom Biddulphia biddulphiana. PLoS ONE 17(9).

Kaczmarska, I., & J.M. Ehrman. 2021. Enlarge or die! An auxospore perspective on diatom diversification. Organisms Diversity & Evolution doi: 10.1007/s13127-020-00476-7.

Kaczmarska, I., B. Samanta, J.M. Ehrman & E.M.A. Porcher. 2019. Auxosporulation in Chaetoceros acadianus sp. nov. (Bacillariophyceae), a new member of the Section Compressa. European Journal of Phycology 54: 206-221.

Davidovich, N.A., O.I. Davidovich, Y.A. Podunay, R. Gastineau, I. Kaczmarska, A. PoulíČková, & A. Witkowski. 2017. Ardissonea crystallina has a type of sexual reproduction that is unusual for centric diatoms. Scientific Reports 7: 14670.

Luddington I.A., C. Lovejoy & I. Kaczmarska. 2016 Species-rich meta-communities of the diatom order Thalassiosirales in the Arctic and northern Atlantic Ocean. Journal of Plankton Research 38: 781-797.

Kaczmarska I. & J.M. Ehrman. 2015 Auxosporulation in Paralia guyana MacGillivary (Bacillariophyta) and possible new insights into the habit of the earliest diatoms. PLoS ONE 10: e0141150.

Edgar R., D. Drolet, J.M. Ehrman & I. Kaczmarska. 2014. Motile male gametes of the araphid diatom Tabularia fasciculata search randomly for mates. PLoS ONE 9: e101767.


M.Sc.  Jagellonian University (Krakow) Aquatic Biology

Ph.D.  Jagellonian University (Krakow) Botany


Undergraduate and Graduate Courses 

Biol 4951 - Independent Study in Biology: ecology of marshland and mudflat diatoms.
Biol 4950 - Independent Study in Biology: ecology of marine diatoms and other protists.
Biol 4990 - Honours Thesis: reproductive biology of diatoms (see current projects below).
Biol 5393 - Graduate Level Topics in Biology: evolution and ecology of marine diatoms.


  • Evolution of Diatoms: developmental, molecular and fossil evidence (NSERC, with B. Samanta at GITAM)
  • Application of artificial intelligence and other computing techniques in biological imaging (with J. M. Ehrman, Digital Microscopy Facility, NBIF)

Part Time Laboratory Technician

Science students or recent graduates are invited to apply for a part time Laboratory Technician opening in Marine Botany Laboratory. Pending satisfactory performance, this position may be available for up to 3 years. The first three months will be treated as probationary. Work time is up to 20 hours/week. Applications will be accepted until a suitable candidate is found.

Responsibilities: Digital image and   data collection, entry, and       manipulation, caring for microbial   cultures, microscopy, and other laboratory duties as needed in the research program of Dr. I. Kaczmarska. Instruction in all responsibilities will be given. Occasional assistance with field work may be required.

Qualifications: Good standing or previous experience in marine science and/or microbial biology. Experience in computer science and/or in microscopy and familiarity with basic descriptive statistics would be an asset.

Remuneration:  Depending on qualifications but comparable to wages in similar positions on campus. Benefits comparable to those of a grant-supported employee at Mount Allison University.

To apply: Please contact Dr. I. Kaczmarska at: for specifics.

Graduate Research Opportunities

Biological and Computer Sciences

1. Merging theoretical reproductive strategies of diatoms with population cell-size data in fossil or extant settings.

This project is directed toward candidates interested in diatoms and their unusual life cycles. Both empirical evidence and theoretical attributes of specific cycles will be considered. The project aims to test some of the common assumptions leading to inconsistencies in the available published evidence for both.

Biological Science

2. Auxospore structure and development in selected diatoms.

Circular on ellipsoidal valve outline is relatively common among diatoms. Recent advances in molecular phylogeny indicate that generally similar overall frustule structure in many of them does not mean that they are closely related. Although the process of sexual reproduction in some species have been examined using light microscopy, the fine structure and ontogeny of their sexual cells are poorly known. The aim of this study is to address this gap in knowledge and to analytically compare molecular and developmental relationships between relevant genera.

Paleoenvironmental Science

3. Diversity and ecology of the Oligocene Cymatosirales.

Extant species of many members of the diatom class Mediophyceae (e.g., Cymatosirales Thalassiosirales) have relatively weakly silicified frustules which result in their poor fossilization. The sedimentary environment from the Oligocene Carpathian Flysh facilitated exceptionally good preservation and rich flora of such species. Both diversity and palaeoecological setting of these species during the Early Oligocene will be investigated. Results will be placed in the context of the environment where their closest relatives thrive today.

Please contact I. Kaczmarska ( regarding the projects and Graduate Studies ( regarding admission.