Luminescent palimpsest is act of witnessing the light of memory. The bioluminescence of the plankton is both a response to my presence and a trace it leaves of itself. Their light emerges from interactions with the environment. As the same stimulus repeats, it grows weaker, yet instead of disappearing, it accumulates into another layer that becomes memory, with the plankton functioning as a memory device.

I follow this light to observe a way of remembering that belongs not to humans alone, but to life and the environment together. The camera acts as a memory translator, transforming the fleeting biological reactions of the plankton into visible traces that the human eye can perceive. Ultimately, this work explores the layered memory written in light and the shared language that connects the human and the non-human through luminous exchange.

Bioluminescence in marine organisms is mainly blue, which matches the wavelengths that travel farthest through water. The light is produced through a chemical reaction involving the substrate luciferin, the enzyme luciferase, and the presence of oxygen. This reaction is influenced by pH, and it requires that scintillons become more acidic in order for the reaction to proceed. When external forces, such as water movement or waves, disturb the cell, receptors on the cell surface detect the stimulus and send a signal inside the cell to ‘prepare to emit light.’ This stimulus triggers a sudden increase in intracellular calcium concentration, causing the cell membrane to depolarise and generate an action potential. The electrical signal is transmitted to luminescent vesicles, reaching the scintillons inside, where proton (H⁺) influx lowers the pH activates the luciferin-luciferase reaction, resulting in light emission.

However, bioluminescence plankton is most apparent in dark conditions. Even if the biochemical reaction occurs in bright environments, the relatively weak light is masked by ambient illumination. Many marine organisms have evolved to use light in dark habitats for ecological functions such as communication, defence, and prey capture. During the day, plankton perform photosynthesis to capture sunlight, store energy, and support growth, so bioluminescence is rarely observed. At night, or in the absence of ambient light, they respond to external stimuli by activating light emission, which serves ecological purposes such as predator avoidance and signalling.

The bioluminescent plankton were grown in San Francisco and shipped to London. To induce bioluminescence, the plankton were placed in a container and stimulated in various ways, including gently shaking the container, stirring with a stick, and tapping the container, to confirm their light emission. Subsequently, the same stimuli were applied repeatedly, and it was observed that as the plankton ‘remembered’ the stimuli, the amount of light emitted gradually decreased. The photography was conducted after these preliminary tests to capture this behaviour.

The camera works as a memory translator, turning these short biological reactions into visible, material traces through choices of exposure, shutter speed, focus, and framing. Cameras capture images by adjusting aperture, shutter speed, and ISO, where the aperture controls the amount of light entering the lens, the shutter speed determines how long this light reaches the sensor, and ISO adjusts the sensor’s sensitivity to light, allowing photography even in dark conditions.