Performing Solidarities

Existing between categories, algae have long resisted stable classification. Although often categorized as eukaryotic protists rather than plants, some algae photosynthesize and have fundamentally shaped planetary life. Among Earth's oldest organisms, they transformed the atmosphere during the Great Oxidation Event around 2.4 billion years ago, and their presence on the planet is still key to the oxygen and carbon cycles. In addition to this great role at the planetary level, algae have been a key ingredient and nutrient in the culinary world for centuries. Today, spirulina is widely promoted as a plant-based superfood, while other forms of algae can become highly toxic under human-made conditions, such as water pollution which can cause harmful algal blooms and ecosystem collapse.

Their significance extends beyond biological into geological, ecological, technological, and cultural imaginaries. It is precisely this capacity to destabilize fixed categories which…