Why did the worm want to go to space? Credit: Miha Turšič
Editorial: Homo Photosyntheticus
1972, atmospheric scientist James Lovelock undertook a scientific
to the planetary oceans to measure the various
of the abundant
dimethyl sulfide (DMS),
its climate-cooling effect
by decreasing the amount of solar radiation that reaches the Earth's
of DMS in the atmosphere condenses
water vapor, leading to the formation of clouds. Lovelock
mostly interested in the fact
the organic sulfur
from its precursor
Dimethylsulphoniopropionate (DMSP), a
phytoplankton and algae,
thus able to
reveal the climate feedback loop correlating DMS production by marine
phytoplankton with cloud reflection
observation led him to publish, that same year, the first article on
the Gaia hypothesis, “Gaia as seen through the atmosphere”1.
It is furthermore estimated that 50–80% of the Earth’s oxygen
production comes from the ocean – from oceanic plankton, algae and
some bacteria capable of photosynthesis. One species in particular,
the cyanobacteria Prochlorococcus, which is the smallest
photosynthetic organism of Earth, alone produces 20% of the oxygen in
the whole of our biosphere. This percentage is higher than all
terrestrial tropical forests combined and
illustrating the extent to which phytoplankton and algae are
important for the balance of the biosphere. But with the increase in
green tides, harmful algal blooms and sargassum seas, algae and
cyanobacteria have gained a bad reputation, even though these
proliferations are caused by climate change, ocean acidification and
global warming, chemical and nutrients discharges from deforestation,
the petrochemical industries, industrial livestock farming and other
urgency of the environmental crisis demands societal change –
reducing the collective carbon footprint, embracing sustainable
energies, food alternatives and new ways of living.
yet, algae offer huge potential for overcoming the environmental
catastrophes of the Anthropocene. Algae can be used as biofuels,
biomaterials, pharmaceuticals and cosmetics. Their nutritional role
is recognized, rich in proteins, minerals, fatty acids and vitamins.
Cyanobacteria known as spirulina and the micro-algae chlorella are
promising food alternatives, and the food cultures of northeast Asia
did not wait for the environmental crises of the 20th century to
embrace macro-algae such as kombu, wakame and porphyra (nori) in
their diets. The umami flavor of kombu seaweed was discovered in the
early 20th century. Control of the lifecycle of nori seaweed by the
British scientist Kathleen Drew-Baker2
after World War Two gave
a new start to the nori Japanese fishermen in need of resilience.
A more recent scientific study conducted at the Roscoff Biological
Station in the French department of Finistère3
even described how the microbiota of the Japanese has undergone
evolutionary lateral gene transfer to better digest nori. Now, in the
21st century, global food cultures are slowly
beginning to incorporate macro-algae such as kombu, wakame and nori
into their diets,
might we consume more algae around our tables?
marine life, many species (the sea slug Elysia
leaf sheep, etc.) have even successfully incorporated microalgae into
their tissue over the course of their evolution in order to benefit
from their photosynthesis. The evolutionary biologist Lynn Margulis
was fond of mentioning Symsagittifera
roscoffensis, the Roscoff
marine worm from Brittany, a wholly photosymbiotic species that
ingests but does not digest its symbiotic micro-algae, keeping it in
its tissue and surviving entirely through its photosynthesis.
Margulis and Dorion Sagan speculate on this animal-algae, expanding
reflection toward a future “Homo Photosyntheticus” of the human
species, a future in our evolution in which humans would become fully
phototrophic, a human-plant with no need to feed4,
thus approaching the early speculations of Vladimir Vernadsky, the
scientist who defined the notion of the Biosphere in the 1920s. More
recently, these marine photosymbioses have inspired medical and
biomedical research. Many research teams are trying to take advantage
of this photosymbiotic logic to integrate micro-algae on or in
damaged human tissue for regeneration through their photosynthesis5.
The speculations of Margulis and Vernadsky have also inspired
speculative bio-artists and science fiction writers. From Quimera
Špela Petrič and Robertina Šebjanič,
from Ursula Le Guin to Kim Stanley Robinson6,
it is a future “Homo Photosyntheticus” that seems to be opening
up to humankind.
So how to draw inspiration from this speculative shift to a “Homo Photosyntheticus”? Margulis and Sagan envisioned it as enabling humans to become multi-planetary. The European Space Agency’s MELISSA (Multi-Ecological Life Support System Alternative) program7 is considering circular systems for life on other planets, imagining the cultivation of spirulina as an alternative food and oxygen source. The Multicellular Marine Models aboratory at the Roscoff Biological Station8 is planning to study the Roscoff worm in space to better understand its photosymbiotic life cycle and its tissue regeneration capacities. Why? Perhaps because we still only know far too little about the oceans, holobionts and the life of algae, these protists that are “queering” conventional taxonomy. Is the objective to go from the ocean floor to outer space and back to Earth, the ocean planet? To finally leave the Anthropocene and enter this Chthulucene9 that the philosopher and zoologist Donna Haraway is calling for?
Ewen Chardronnet & Maya Minder
1J. E. Lovelock, « Gaia as seen through the atmosphere », P. Westbroek & E. W. deJong (eds.), Biomineralization and Biological Metal Accumulation, D. Reidel Publishing Company, 1983, pp.15-25. Online at: http://www.jameslovelock.org/g...
3Hehemann, Jan-Hendrik et al. “Transfer of carbohydrate-active enzymes from marine bacteria to Japanese gut microbiota.” Nature vol. 464,7290 (2010): 908-12. Online at: https://www.nature.com/article...
4Lynn Margulis & Dorion Sagan, Microcosmos, Summit Books, 1986.
5Chávez, Myra N et al. “Photosymbiosis for Biomedical Applications.” Frontiers in bioengineering and biotechnology vol. 8 577204. 6 Oct. 2020.
9Donna J. Haraway, Staying with the Trouble, Duke University Press, 2016.