For the last century, science has been struggling to understand Earth’s largest body of ecology: the oceans. A problem is that these studies have automatically applied a land-based food chain concept, where plants support the growth of animals, to the seas. According to such thinking, single-celled microalgae are consumed by single-celled zooplankton, which in turn are eaten by multi-celled plankton such as krill. The krill are eaten by jellyfish, who are then gobbled up by fish, turtles or whales – and so on up the food chain.
In reality, however, our ocean’s food chains are ‘ruled’ by single-celled organisms that are neither plants nor animals, but a little of both. Called mixoplankton, these organisms are unique in that they can both photosynthesise like plants and hunt like animals.
“When discussing ocean life, most biology and ecology textbooks – even programmes like the BBC’s renowned ‘Blue Planet’ – still use plant-like and animal-like descriptors,” says Aditee Mitra, a research fellow at Cardiff University’s School of Earth and Environmental Sciences. “Now that we know this represents a gross simplification, if not a flawed description, and that marine science has been studying the wrong things in the wrong organisms, it is time we do something about it.”
The EU-funded MixITiN project is doing something about it. “Through this Marie Skłodowska-Curie Action, we are working to train an innovative team of young researchers in using the correct mixoplankton paradigm, where mixoplankton rule the waves,” she adds.
New tools for understanding what’s going on
The main objective of the MixITiN project is to research the role of mixoplankton in marine ecology. To do so, researchers have been conducting a variety of field, laboratory and computer-based experiments. “As with any new branch of natural sciences, our challenge has been developing the tools and skills needed to properly understand what’s going on in nature,” explains Mitra.
According to Mitra, doing so is easier said than done. “We quickly found that the research tools for studying marine systems that have been used for decades were inadequate for use within this new mixoplankton paradigm,” notes Mitra.
For the MixITiN research team, this meant going back to the drawing board. “We conducted a thorough reappraisal of the field and laboratory techniques and models used for studying our oceans and predicting the impact that climate change has on them,” remarks Mitra.
Based on this assessment, the team is developing next-generation simulation models for conducting water quality and climate change research. They have also created new techniques for isolating mixoplankton from natural waters, allowing researchers to better study them in a laboratory setting.
Changing how we teach ocean ecology
Despite the importance of these new methods and tools, the restructuring of how we study our oceans really starts in the classroom. “A major component of this project has been changing how we teach ocean ecology,” says Mitra. “To succeed, we need to start at the ground level and work our way up.”
Although this effort remains ongoing, the project has already presented work at several major international conferences. They have also produced a range of teaching materials geared towards secondary- and university-level students, along with an in-depth manual on the upkeep of mixoplankton for laboratory experiments.
“Our simple mixoplankton food chain model has been used for outreach and educational activities as far away as India and China,” remarks Mitra. “And our research manual is currently being used to support the EU-funded MixoHUB project (funded partly through the European Regional Development Fund) – which builds on the legacy of MixITiN.”