Anna-Adriana Anschütz, ESR8, ponders about mixoplankton, Hamlet and Helsingør
A year has passed since the last time I visited Helsingør, Denmark. That time, I met up with the other MixITiN ESRs to learn culturing techniques for mixoplankton. This year, I returned for two months to culture one of the mixoplankton species I study. I looked eagerly forward to my secondment in Helsingør, which is famously known as Elsinore, home to Shakespeare’s Hamlet’s castle.
At first glance, Shakespeare and marine ecology seem like very different interests. However, from a certain perspective they are both interesting for very similar reasons. Looking at a marine food web is a bit like reading Hamlet for the first time. The links between characters are very difficult to follow, it is hard to understand who kills whom and for what reason and sometimes a sudden death occurs that no one can explain. Hamlet is such an eventful play with manifold and complicated links between the characters that the main character being captured by pirates is not even a major plot twist – something that would be the main selling point for other books is often not even mentioned in most summaries about this play.
At the centre is young prince Hamlet who slowly descends into madness when he learns that his uncle seized the Danish throne by treacherously murdering his (Hamlet’s) father and marrying the queen (Hamlet’s mother). In his attempt to correct this injustice, almost all the characters end up dead regardless of their innocence through some level of connection to the main character. The plot seems so fantastically complicated that it seems almost unrealistic. Looking at food webs we find similarly complicated scenarios.
We do not have to look far from Hamlet’s castle to find a tiny mixoplankton drama. In the seas around Denmark and, in fact in all the coastal regions of the world, we find a microscopic cryptophyte called Teleaulax: a single celled protist that has one chloroplast for photosynthesis. Teleaulax peacefully photosynthesises most of the time and occasionally snacks on bacteria. Unfortunately, for Teleaulax Denmark’s seas are also home to another mixoplankton species: the ciliate Mesodinium. Mesodinium is the cheetah among ciliates that moves incredibly fast. It does not have its own chloroplasts, but is able to use and maintain those of Teleaulax for quite some time. Mesodinium therefore hunts Teleaulax and steals the chloroplast after ingesting it and then makes food through photosynthesis. Mesodinium can accumulate chloroplasts from several Teleaulax cells and use them for photosynthesis to provide energy for its much larger cell. For now, it seems as if Mesodinium is the tyrant.
Next scene – enter dinoflagellate Dinophysis. This mixoplankton is also dependent on the chloroplasts of Teleaulax for photosynthesis. However, Teleaulax is too small for Dinophysis to ingest. So instead of hunting Teleaulax directly and gathering chloroplasts one by one, Dinophysis goes after Mesodinium and robs it off its stolen collection of Teleaulax chloroplasts. Dinophysis is by far not as fast and agile a swimmer as Mesodinium. However, Dinophysis is treacherous. It ambushes Mesodinium and uses advanced weaponry such as toxins and “spears” as capture strategy. Once Mesodinium is hit by the toxin, it slows down and can be captured by Dinophysis. In true Shakespearean fashion, the drama does not end here. If Dinophysis is in an environment where it can be particularly adept at causing mischief, it will form blooms that make shellfish toxic for humans to eat. Dinophysis is notorious for causing diarrhetic shellfish poisoning and has often led to the shutdown of shellfish aquacultures. This reminds me of how the Norwegian crown prince Fortinbras in Hamlet only perceives the downfall of Denmark without knowing about all the little plot twists that led up to it.
When I arrived in Helsingør on a lovely day in May, and the beautiful castle proudly contrasted the blue sky, it was difficult to imagine it as the backdrop of a drama. It seemed almost like a cheery promise for a good time I would spend here. A promise well kept. The reason I came to Denmark was to get more information on the plot twists of the Teleaulax–Mesodinium–Dinophysis complex. I wanted to learn which conditions Teleaulax needs “to be or not to be” abundant. As luck would have it, I successfully grew the little cells in the laboratory under different conditions and “measure for measure” filled my pen drive with data. Thankfully, there was no “labour lost” and so I continue to work on my results back in Wales. It seems that my experiments resembled rather a Shakespearean comedy than a drama. All’s well that ends well.