Conference catch-up: Seventh European Phycological Congress Zagreb, Croatia – algae and abominable life cycles!

The first European Phycological Congress was held in Cologne, Germany in 1996. In the last 20-odd years, the meeting has been held every four years since then in Italy, Northern Ireland, Spain, Greece, and then in London in 2015 (see posts from this last EPC here and here).

This year, the Seventh EPC was held in Zagreb, Croatia from 25-30 August. Each day began with a plenary lecture followed by symposia and poster sessions, as well as a silent auction and a banquet. All presentations and events occurred at the Esplanade Hotel, a hotel that was a stop over on the Orient Express. I’ve recapped a selection of talks from each day below.

Participants of EPC 7 in Zagreb, Croatia. Apparently, our assembly by the hotel resulted in a police action as we had a huge group with no announcement of a public gathering! Not bad for a group of phycologists. © EPC 7

Day 1: 26 August

The first plenary was given by Assaf Vardi from the Weizmann Institute of Science in Israel. His talk focused on microalgae – the metabolic cross-talk during host-pathogen arms races at sea. Algal blooms account for 50% of the photosynthetic activity, but only 0.1% of the photosynthetic biomass. The booms and busts of algal blooms take weeks compared to the turnover of years in terrestrial ecosystems.

The hard part of studying these phenomena is equating the natural environment and its complexity with the lab model systems. His talk was a comprehensive take on his lab’s work on the metabolic seascape within microbial food webs, including really cool work published this year in PLoS Pathogens by Rosenwasser and co-authors.

I attended the symposium on algae in a changing environment organized by Inka Bartsch and Christian Wilhelm. Francisco Gordillo presented work on algae in the Kongsfjord in Svalbard – increases in temperature aren’t the same across the seasons. For algae in the arctic, for more than three months in the summer they get non-stop light, but in the winter, they go months with not a single photon.

Guillermo Diaz-Pulido presented work on coralline algae, specifically how important understanding the evolutionary history of different groups of corallines is to our understanding their responses to climate change. More recently diverged lineages are more susceptible to ocean acidification.

After the first day, we went to dinner to with my PhD supervisor and some colleagues, and found a travel agency with a very apt name:

Alga! With fellow UAB phycologist, PhD student Sabrina Heiser. © SA Krueger-Hadfield

Day 2: 27 August

The plenary was given by Laura Airoldi from the University of Bologna. Her plenary was focused on the worldwide decline of canopy-forming seaweeds. We don’t understand why these really important ecosystem engineers are in decline and the declines have been long underestimated. She showed experimental data suggesting that the control of local stressors (e.g., marine-protected areas, water quality improvement) could mitigate short-term effects, possibly allowing these ecosystems time to adjust to climate change. She also talked about reforestation efforts and more controversial issues, such as the potential for accepting novel ecosystem states.

Heroen Verbruggen presented data on diversification trends in the Archaeplastida. rbcL phylogenies offered poor resolution of some groups, but when chloroplast genomes were used, phylogenies were resolved with full support, clearing up some of the red algal relationships.

Christophe Destombe explained the complicated history of hybridization between two species of red algae in the genus Gracilaria. Hybrids are mixed phase with diploid and female tissue, but appear to have lost the ability to undergo meiosis and reproduce asexually. Red algae are sometimes just too complicated!

Les roscovites – the current and former Station Biologique de Roscoff EPC delegates. © F Not

Day 3: 28 August

Krapina Neaderthal Museum exhibit. © SA Krueger-Hadfield

While there were workshops on the mid-conference day, we took part in the full day conference excursion. Our first stop was at the Krapina Neanderthal Museum. The museum has an excellent progression through time starting from the formation of the Earth through to present day as you spiral up to the second floor. The DNA helix made up for the fact we couldn’t go to the actual excavation site.

We were then taken to the Veliki Tabor Castle – a fortress in northern Croatia followed by a lunch at the Gresna Gorica Cottage. The excursion ended at The Old Village Museum before heading back to Zagreb and an art exhibition.

Day 4: 29 August

The third day of symposia began with a plenary by Debashish Bhattacharya on fractured fairytales – algal genomes during and after plastid endosymbioses. His talk was the sequencing from Destombe’s presentation about red algal gene flow … algal life cycles are abominable. Darwin described the abominable mystery of the radiation of plants, but so is the evolution of red seaweeds. There is parallel stabilization of organelle genomes with both reds and plants, but the red algal ancestor must have evolved in a highly selective and stressful environment. He also presented data on his lab’s work on Paulinella that may enable us to reconstruct early events that mark the transition from symbiont to organelle. Really, the abominable life cycle was the perfect intro to the talks later that day (including mine!).

Frederik Leliaert showed us that algal biodiversity follows the same patterns as animals. The lack of species diversity in the tropics isn’t because there are actually fewer species, but just that we have studied this area much less! He showed data from Portieria and the algal order Dictyotales that supports the coral triangle diversity pattern found in animals, more sampling of the appropriate kind (e.g., using genetic tools) results in many new species being found!

Aga Lipinska followed later by Susana Coelho presented data from the algal genetics group at Roscoff on the UV sex determination in haplodiplontic algae. No, that’s not ultraviolet, but rather when the sex is determined in the haploid stage: U is female and V is male. Our knowledge of sex determination is based on XY and ZW systems in which sex is determined in the diploid stage. It seems that the female is the default program as the introduction of one male chromosome seems to turn on ‘maleness.’

Fancy diatom-esque ceiling fixture in one of the rooms used for some of the symposia. © themudvision

Anke Kremp presented work on phytoplankton life cycle processes that affect genetic diversity and population structure. Some of this work was also generated in collaboration with Anna Godhe who sadly passed away earlier this year. There are many unique genotypes in Skeletonema blooms and relevant phenotypic variation that might lead to adaptation.

Day 5: 30 August

The final day began with a plenary by Myriam Valero on the evolution of haploid-diploid (or haplodiplontic) life cycles. Naturally, this was one of my favorite talks! The evolution of life cycles is tightly linked to sexual reproduction. She traced the history of thinking about the paradox of sex and then presented data from red and brown seaweeds on how these haplodiplontic life cycles evolve and are maintained (you need to study ecology AND evolution). Yet, we need a lot more data to really understand these processes and there are simply too few studies of mating system variation in haplodiplontic taxa to really make sense of patterns!

Before flying home, we took a little time to wander around Zagreb:

Beautiful architecture seen on our walk every day from our airbnb to the Esplanade Hotel. © SA Krueger-Hadfield
Found on a side of a building on one of our wanderings. © SA Krueger-Hadfield
Souvenirs. © SA Krueger-Hadfield
Cathedral with the shiniest tiles I’ve ever seen. © SA Krueger-Hadfield

Thank you to the organizers for a great conference. As always, these meetings are inspiring. Myriam said it best in her plenary that phycology meetings are always friendly! She’s a population geneticist, but has always been welcomed at these meetings. Even as a phycologist, I always look forward to these meetings. And, as a shameless plug, if you read this blog and love algae, consider the Southeastern Phycological Colloquy on 26 October in Birmingham, AL!

About Stacy Krueger-Hadfield

I am a marine evolutionary ecologist interested in the impacts of seascapes and complex life cycles on marine population dynamics. I use natural history, manipulative field experiments and population genetic and genomic approaches with algal and invertebrate models in temperate rocky shores,estuaries and the open ocean.
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