Teratotheca: building a global database of diatom deformations

by Pierre Villefourceix-Gimenez |

Frustule deformations are common in diatoms, especially when stressed. In publications mentioning these teratologies, the presence of toxic contaminants (e.g. trace metals) is the most often mentioned probable cause (Falasco et al. 2021). Therefore, some diatom indices used in biomonitoring consider the relative abundance of teratologies as a downgrading criterion for water quality assessment (e.g. Coste et al. 2009). In practice, deformations are generally overlooked by biomonitoring networks, because of the difficulty to draw a line between normality and (slight) deformation. This can lead to serious overestimation of water quality scores (Olenici et al. 2020).

To tackle this, we have built the Teratotheca, an online interface displaying pictures of both healthy and deformed diatoms, allowing for quick visual comparisons, and hopefully providing support to biomonitoring operators. Our approach is based on data sharing: that is to say, we provide the ability to any diatomist to share their own pictures of diatoms, adding to the available collection. This way, we hope to provide teratological illustrations for a high number of taxa, outside the bounds of those most studied by scientists. A user account system allows us to guarantee the quality of contributions and the respect of intellectual property.

Though built as an illustrative reference, we have high expectations for scientific uses of the underlying database. By themselves, a variety of pictures would allow us to showcase the continuum of deformation severity. While adding a new picture, a contributor may provide some insight on the putative cause of the deformation. This could allow us to point out the link between the type or severity of a deformation and the cause of stress, if such a link was to exist. Provided we gather enough data, we could even build an algorithm for teratology recognition, which could work as a “drag-and-drop” service on the website!

The Teratotheca is available here: diatom-terato.eabx.inrae.fr/en . A link to contact me is available at the bottom of each page, in case you ever need. Feel free to have a look and, why not, to share your own pictures!

Gomphonema gracile, left: healthy, right: teratological. © Soizic Morin

REFERENCES

Cerisier A., Vedrenne J., Lavoie I., Morin S. 2019. Assessing the severity of diatom deformities using geometric morphometry. Botany Letters 166:32-40. DOI : 1080/23818107.2018.1474800

Coste M., Boutry S., Tison-Rosebery J., Delmas F. 2009. Improvements of the Biological Diatom Index (BDI): Description and efficiency of the new version (BDI-2006). Ecological Indicators 9:621-650. DOI : 1016/j.ecolind.2008.06.003

Falasco E., Ector L., Wetzel C.E., Badino G., Bona F. 2021. Looking back, looking forward: a review of the new literature on diatom teratological forms (2010–2020). Hydrobiologia 848:1675–1753. DOI : 1007/s10750-021-04540-x

Olenici A., Baciu C., Blanco S., Morin S. 2020. Naturally and Environmentally Driven Variations in Diatom Morphology: Implications for Diatom-Based Assessment of Water Quality. In: Cristóbal, G., Blanco, S., Bueno, G. (eds) Modern Trends in Diatom Identification. Developments in Applied Phycology vol 10. Springer, Cham. DOI : 1007/978-3-030-39212-3_4

Vallanzasca I., Boutry S., Laviale M., Quinton E., Morin S. 2023. Development of a collaborative web platform documenting the diversity and extent of diatom deformities. Botany Letters. DOI : 1080/23818107.2023.2183898