IDS 2021 – Online International Diatom Symposium

August 23rd – 25th

Scientific content
Keynote speakers
Format and instructions
Key Dates
Schedule at a glance
Detailed program
How to prepare the abstract
Virtual format
Networking and other activities
How can I record myself
Registration fee
Code of Conduct
Organization team IDS 2021


Scientific content

This year’s IDS includes early and mid career plenary speakers, oral and poster sessions, social gatherings, and an opportunity to meet colleagues.

Keynote Speakers

Eveline Pinseel

Eveline Pinseel

University of Arkansas

Poles apart: the historical biogeography of freshwater polar diatom communities

Despite evidence for significant levels of endemism among various microbial groups, a comprehensive understanding of the evolution of regional microbiota and how they are shaped by tectonic and paleoclimate events remains virtually lacking. Here, we combine evidence of contemporary and fossil diatom assemblages, molecular phylogenies, and next generation environmental amplicon sequencing to provide insights into the biogeographical and evolutionary history of polar freshwater and terrestrial diatom biomes, with a main focus on Antarctica. We reveal evidence for widespread but selective extinction among an ancient Antarctic diatom flora in response to major climate perturbations since the middle Miocene. Climatic sorting of regional Antarctic diatom floras further resulted in the current bioregionalization patterns in the Antarctic diatom biome, with high levels of endemism. In parallel, molecular data are indicative of multiple colonization events of Antarctica during the past 25 million years, and reveal strikingly different patterns of inter- and intraspecific variation in Arctic and Antarctic diatoms. Altogether, our data suggest that historical processes (geology and climate) have been crucial in shaping the history of Antarctic microbial lineages, in similar ways as these processes affected the biogeography and diversity of polar macrobiota.


Xavier Benito

Xavier Benito-Granell


Shifts, baselines and non-linearities: quantifying paleolimnological resilience using diatoms

Managing current ecosystem states requires an understanding at which levels of perturbation function and structure are stable, and unprecedented when considering longer timescales—in other words, knowing their safe operating spaces. This conceptual framework is coined as the defining characteristic of the Anthropocene and relies upon accelerating rates of change and concepts such as resilience to detect early warnings of regime shifts or restoration to pre-impact background levels. Paleolimnological time series have potential to reveal changes in resilience by capturing regime shifts and documenting multiple shifting baselines linking driver-response variables to understand underlying processes. However, evidence linking environmental variation to regime shifts is often restricted to small spatio-temporal scales, hindering the study of spatially synchronous changes and generalization across large areas. In this talk I will present three different lines of research that can enable a better profiling of resilience signatures by applying novel synthesis limnological-paleolimnological approaches using diatoms. First, anthropogenic and natural disturbances are widespread in many parts of the tropical Andes but there is a lack of mechanistic understanding on how these factors drive diatom community changes. Second, if past climate and anthropogenic impacts controlled lake ecosystem transitions, there is an urgent need to improve statistical techniques that capture spatial and temporal indicators of resilience loss to predict future changes (“the past is the key to present”). Third, as global change impacts intensify and synchronize across large areas (i.e. Moran effect) a better understanding of higher levels of biological organization of diatoms (e.g. metacommunities) and regional environmental correlates is required. Large-scale diatom datasets linking species distribution and predictors that describe local (limnological) and regional (geo-climatic) factors can help to develop joint projects and hypotheses on the mechanisms driving microbial diversity and community assembly to inform biomonitoring programs.


Luca Pellegrino

Luca Pellegrino

Universitá degli Studi di Torino

Looking for diatoms below and within the Messinian Salt Giant: state of the art, open questions and future directions

The late Miocene (11.63-5.33 Ma) was characterized by remarkable paleoclimatic and paleoceanographic reconfigurations, in turn associated with a global intensification of the diatomaceous deposition. Furthermore, the Mediterranean area experienced similar processes: here, the cyclic deposition of diatom-bearing sediments reached a peak at about 7-6 Ma, before the Mediterranean was turned into the youngest salt giant of Earth history during the Messinian salinity crisis (5.97-5.33 Ma). In the last decades, many efforts have been made to better constrain the major causes triggering the deposition of the diatomaceous sediments and the overlying evaporites during the Messinian. The former has been mostly framed within a strictly regional scenario typified by the strengthening of upwelling currents and the establishment of deep-water anoxia in response to the progressive closure of the Mediterranean-Atlantic gateways, which started at about 7.2 Ma. However, the coeval world occurrence of a ‘biogenic bloom’ event, the presence of remains of diatoms adapted to exploit seasonally-stratified waters and the micropaleontological and sedimentological evidence of bottom water ventilation, possibly suggests a global control and other interpretations of the water column conditions and the sedimentary environment. On the other hand, for a long time the Messinian evaporites have been related to the complete desiccation of the Mediterranean, when it was finally cut off from the oceanic circulation at about 6 Ma; the progressive build-up of hypersaline conditions in the water column would have ‘annihilated’ the Mediterranean eukaryotic biota. Accordingly, any attempt at characterize the paleobiological content of Messinian evaporites was discouraged by the common belief that evaporites are barren. However, recent investigations point to a more complex scenario, where diatoms may have played a critical role, especially in fuelling benthic bacterial communities involved in the sulfur biogeochemical cycle.

Even though much has been done already, more effort is needed in order to fully understand the events related to the Messinian salinity crisis, and it is expected that the diatomist community will be at the forefront of this exciting line of research. Future steps in this field must be aimed at characterizing the diatomaceous deposits formed before and during the salinity crisis at the lamina-scale using non-destructive analyses, comparing the results with coeval world deposits in order to highlight possible similarities and discrepancies in the processes governing the diatomaceous accumulation during the latest Miocene; (bio)geochemical investigations, especially concerning the sources of dissolved silica exploited by diatoms and the diagenetic transformations of biogenic silica are urgently needed. Finally, the diatom content of the entire thickness of Messinian evaporites must be thoroughly explored.


Elena Jovanovska

Elena Jovanovska

Senckenberg Museum Frankfurt, Germany


Drivers and dynamics of diversification and community assembly in diatoms over evolutionary time: Lake Ohrid as a case study

Insular settings in old environments – such as oceanic islands, ancient lakes, or mountain tops – are prime model systems for studying fundamental processes in ecology and evolution. Ancient lakes are of particular interest, because their sediments are typically well constrained in age and rich in fossils, providing the opportunity for merging paleontological information with neontological data to independently study mode, tempo, and drivers of biological diversification. There are only a few ancient lakes in the world, including Baikal, Tanganyika, Malawi, Titicaca, and Ohrid, but they are all known for enigmatic species flocks of fishes, mollusks, crustaceans, and diatoms. The relatively small Lake Ohrid located on the Balkan Peninsula in Europe stands out as the only ancient lake to date with a completely recovered limnological history. Using a framework that integrates paleontological and neontological data on Lake Ohrid’s diatoms, we have unraveled the drivers and dynamics of diatom diversification and community assembly since the inception of the system, at scales that include establishment, speciation, (local)extinction, and in situ adaptive trait changes. I then highlight, based on empirical modeling studies, future perspectives how research in ancient lakes can improve our understanding of the ecology and evolution of diatoms. Applying such a comprehensive framework allows us to challenge ecological and evolutionary predictions related to island biogeography theory.


Norico Yamada

Norico Yamada

University of Konstanz


Re-creation of plastid evolution in “dinotoms”: a new model system

In the history of eukaryotes, the endosymbiotic evolution of plastids remains an obscure process. The dinoflagellates “dinotoms” are a newly-established model system that allows us to follow the evolutionary process experimentally. Their diatom-derived plastids exhibit three evolutionary stages depending on the host dinoflagellates: a transiently-maintained kleptoplastic stage (in Durinskia capensis); a stage in which multiple diatoms are permanently maintained (in D. kwazulunatalensis); and a stage in which a single diatom is permanently maintained (in most of dinotoms). By comparing the plastids of these three stages in dinotoms, we can speculate on how independent organisms become enslaved as organelles, and how permanent endosymbionts lose their own organelles and autonomy. I will present past and ongoing research on dinotoms, and discuss future prospects for the endosymbiont studies using dinotoms.


Luis Demetrio Mora

Luis Demetrio Mora

Bundesanstalt für Gewässerkunde, Koblenz, Germany
Fishing for diatoms around eDNA bottlenecks: towards taxonomically validated reference libraries

Environmental DNA (eDNA) metabarcoding is a powerful method revolutionising biodiversity research and ecological assessment. Yet, it still has major bottlenecks, one of them being the taxonomic assignment of the millions of reads generated by High-Throughput Sequencing, mainly due to the incompleteness and inaccuracy of barcode reference libraries. For diatoms, it has been estimated that only about 15% of the species occurring in Europe have at least one reference sequence in publicly available databases. Notwithstanding this low coverage, Europe is by far the region best represented in reference libraries worldwide. In spite of community efforts to curate publicly available sequences, inaccuracies in taxonomic annotation of sequences in reference libraries are widespread. This can hinder inferences on biodiversity monitoring and ecological assessment through eDNA metabarcoding. In this talk, I will summarize studies that illustrate the importance of the completeness and accuracy of diatom barcode reference libraries for biodiversity research and ecological assessment. Additionally, this talk will explore how potentially inaccurate taxonomic annotations can influence the conclusions of eDNA metabarcoding studies. Finally, this presentation highlights how integrative taxonomy approaches can contribute to unblocking this major bottleneck for biodiversity research and ecological assessment, positioning taxonomy and taxonomists at a central role in the era of environmental DNA.


Matt Asgworth

Matt Ashworth

University of Texas at Austin

Molecular phylogeny of the raphid diatoms: grades and clades among the “early-diverging” branches

The relative dearth of sequence data available for raphid pennate diatoms, has significantly impacted our ability to make many inferences about their evolutionary history based on molecular phylogenetics. There is a lack of congruence between current molecular phylogenies and some of the established higher classification systems, and this lack of congruence persists even as additional data are added. This would suggest a required revision in the classification of raphid diatoms. This talk will focus on a group of early-diverging clades and grades in the raphid molecular phylogeny, including the Bacillariales, Achnanthes, Craspedostauros, Staurotropis and several amphoroid clades, outlining what we know, what we don’t and where we might look for answers in resolving the raphid molecular phylogeny going forward.



  • Morphology, taxonomy and phylogeny
  • Paleolimnology and paleoclimate
  • Ecological assessment and metabarcoding
  • Molecular biology and HABs
  • Ecology and biodiversity

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Format and instructions


The online symposium will run through different meeting platforms: Zoom for oral and keynote presentations, and ISDR General Meeting, and for posters, ice-breaker, and Young ISDR events. All platform access links will be available on the symposium site:

Sign-up to obtain a username at by clicking “sign-up here”. Once you enter a valid email address, you will receive an email with username and password confirmation. Complete your registration to IDS (fee payment) before the deadline (August 20) through the dashboard. BUT keep the deadlines in mind for the submission of abstracts, posters and pre-recorded oral presentations.

Our technical team is available to answer any question about accessibility to the different platforms (Zoom and and assist you throughout the meeting. You can contact them at 

Key dates

June 16: 2nd circular, registration and abstract submission open
July 20 August 1: Extended abstract submission deadline
August 1 August 8 August 16: Extended submission of recorded oral presentations and posters
August 20: Posting of symposium schedule, abstracts, recorded oral presentations, and posters
August 20: Registration deadline
August 23-25: Virtual IDS

Schedule at a glance

The conference is organized on Japan Standard Time to reflect the Asiatic origin of the postponed 2020 IDS. The times have been selected to try to accommodate people wherever they are, but because of the big differences in the time zones, some will have to be ‘very early birds’ and others ‘late night owls’.

Download Agenda here: Online IDS timetable



Detailed program

All presentations will be made available prior to the meeting at the symposium site. Click on “oral and poster timetables” at the site’s left-hand menu. Everyone will be able to visualize full-recorded presentations, and to leave comments and questions before the meeting.

Oral presentations (click here to download the oral program)

  • Oral sessions have been organized to foster discussions and questions live. Each presenter will have a 7-min time slot:
    • 1 minute summary of the talk
    • 5 minute discussion on the talk
    • 1 minute change
    • At the end of each session, there should be time for a bit of open discussion on the session topic

Oral programme


Presenters should join 15 minutes before the beginning of the session to check Zoom technical aspects. We recommend sending the presentation slide in pdf format to as a backup file in case of technical issues sharing the screen. Deadline August 23rd. 

Poster sessions (click here to download the poster program)

  • Poster sessions are organized as a 1-hour block after oral sessions each day. Presenters are expected to be next to their poster for 30 minutes on both days (24th, 25th), but can visit others after their allocated time. More especific instructions will be given during the welcome event.
  • Poster sessions will take place in (link will be available on the symposium site) with interactive questions from the participants.

Poster programme

Networking and other activities

The online IDS also includes social gatherings with opportunities to meet new and old colleagues in a relaxed atmosphere. Best oral and poster presentations by students (i.e., master and PhD students and early postdocs) are eligible for prizes. Make sure you join our ice-breaker for the general welcome and a fun diatom trivia on Monday 23, what early-career diatomists can do for you on Tuesday 24 at the Young ISDR meeting, and the ISDR General Meeting and Farewell on Wednesday 25 to discuss the present and future of diatom science.


  • Prizes for the best presentation and best poster will be sponsored by Koeltz Botanical books.

How to prepare the Abstract

  • The abstract must include a representaitve title and preference if the contribution should be a poster or oral presentation. E.g. My Presentation Title (Oral) – Deadline August 1
  • Write max. 500 word / 3,000 character (including spaces) abstract
  • Upload the abstract onto dashboard using the “New Presentation Application” button
  • The maximal number of abstracts uploaded per participants is two: one for a presentation, one for a poster

Virtual format

The 2021 online IDS conference has been organized to foster interactions as much as possible.

  • Links to Zoom and will be found on the dashboard using your log-in details (, where you also will find instructions for abstract / presentation / poster. A user manual is available on the dashboard with detailed instructions.
  • Plenaries (30’ per presenter including presentation and discussion) will happen on the day via Zoom.
  • All presentations will be uploaded on the dashboard prior to the meeting and will be available to participants and attendees for visualization before the IDS starts. Deadline for uploading presentations August 16. 
  • On the day of the meeting, we strongly encourage presenters to be on the room whose presentation must show a one-slide graphical abstract.
    • make a 1-minute summary of your presentation.
    • 5 minutes of discussion follow.
    • 1 minute for the change of presenters.
    • (7 minutes in total. A longer presentation reduces time for discussion).
  • The poster session will be held on, which  enables you to move through a virtual space and gather together with other participants. Participants that get together can then talk with each other, without hearing the rest of participants.

How can I record myself?

  • Submit your video presentation in MP4 format and under 500MB.

Recommended format [Face Camera, and audio Included] The simplest way to record your presentation with your face included is by recording yourself through the Zoom Application. Simply sign into your zoom account, start a personal meeting, screen share your PowerPoint, hit the record button, and begin talking. If you are in need of assistance to record, please let us know by messaging the following e-mail address. <>

[No Face Camera, only audio] The simplest way to record a presentation with only your audio is by utilizing the record function that is inside PowerPoint. If you are unsure of how to do this, please go to the following URL, there is an explanation on how to do so.

If you are in need of assistance to record, please let us know by messaging the following e-mail address. <>

  • Keep your video in under 15 minutes and include a visual of you speaking if possible.
  • Title your video in the following format.

Please write the presentation title. (Please keep it the same title as the one you have submitted to the registration system) Immediately below the presentation title, please write the name(s) of the author(s), and institution, Please also underline who will be presenting.

  • Please save your video file in the following format.

Example: date_given name_family name_video 20210625_john_smith_video 5. The submission deadline is August 1st, 2021((23:59 JST). Please click on the URL below for up to date news!

Registration fee

FullJPY 4,000 (USD 36, EUR 31)JPY 6,000 (USD 55, EUR 46)
StudentFree of ChargeJPY 4,000 (USD 36, EUR 31)*

*NOTE: For non-member students
It’s time for you to join our society – registration fee of this online meeting is waived for student member of ISDR (International Society for Diatom Research).
Student membership is £25 per year. This is equivalent to JPY 3,853 (USD 35, EUR 29) and it includes open access to the journal Diatom Research and further perks explained here:

Code of conduct

We embrace active and respectful participation for all participants and attendees in the online IDS to allow open discussion of presentations during the event and on social media. We strongly encourage you to read the ISDR Code of Conduct.


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Organization team IDS 2021

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