Ode to Photosynthesis
EXT. THE PARK — DAY — SEVERAL CUTS, NATURAL SOUND
WE OPEN on the urban wetland, a representative of a historical habitat no longer common in Indiana. The audio of this video is transcribed below.
Back when it was warm in Indiana, and the skies weren’t grey and swirling with precipitation, one of my favorite places to go was the Nina Mason Pulliam EcoLab. It’s an ecological park in Indiana that’s right off the campus of Marian University.
When I first moved to Baltimore, I instantly fell in love with a tiny urban creek called the Stony Run. It had a “Territory of Feelings” graffiti’d bridge and an “Earth Has Music For Those Who Listen” bench. And I was so moved by this stream that I learned basic editing and dedicated my very first video essay to it. It wasn’t news or a story. It was just a stream. A little bubble of stillness that was somehow more important.
So far, the EcoLab has gotten closest to recreating that feeling of relative isolation and connection to water, along with natural cacophony and a backdrop of dense green.
The wetland is a stark contrast from most of Indiana’s modern habitat. But even with large areas of land being graded and developed for a wide range of purposes, measured by gigaton of carbon, plants still take up the majority of biomass on Earth: about 450 gigatons of carbon (GtC) compared to just 2 GtC for all of animal life.
If you count particular microbes, like cyanobacteria, the Earth is truly dominated by photosynthesizers: organisms that have evolved tiny molecular machines to convert the sun's rays into chemical energy to survive. And, as an added bonus, they create oxygen which goes on a complicated journey.
From the tiny green cells of the algae, plants, and cyanobacteria, oxygen travels through the atmosphere, and into our lungs, which are specifically crafted to allow contact of this oxygen with our blood vessels, so the oxygen can bind to a protein in our blood called hemoglobin, and subsequently be spread throughout the body and be delivered to cells that need that oxygen as building block for the synthesis of ATP — the cellular currency of energy and the reason we are all alive.
In some albeit indirect way, the gazillion cells making up the photosynthesizers I’m surrounded by here have a very intimate connection with the 30 or so trillion cells that make up my body.
Added all up, their cells and mine are greater in number than all the stars in the Milky Way Galaxy.
And that’s just the start. You might remember seeing a diagram of a cell with all its tiny compartments and organelles, each with a job to do. Each cell in my body and yours, is equipped with these little molecular machines. And each machine, say a ribosome, for example, is composed of protein subunits generated by one of the 25,000 or so protein-coding genes in the human genome.
The protein-coding genes are only about 1% of the entire genome. And even among the protein coders, we only know the function of a few of these genes — with most of our focus being dedicated to just around 2,000. Thinking of this always makes me wonder how much we can consider the human genome a “map” and how many incorrect assumptions we’re making when we blame our genes for who we are.
But back to the photosynthesizers, which are the reason I’m even able to conceive of my own genome. Some evidence suggests photosynthesis evolved around 3.2 or 3.5 billion years ago, in microbes with much smaller genomes to work with.
Cyanobacteria were probably among the first photosynthesizers. And despite being unicellular, they are deemed responsible for the great oxygenation event, a time around 2.3 billion-years-ago (bya) when an atmosphere scant in oxygen became full of it. Tiny little cells changed the geological and biological trajectory of the Earth for good.
Cyanobacteria have different molecular systems to work with, each playing a specific role in this solar-to-chemical energy process. There are pigment complexes and phycobilisomes to absorb light, photosystems to transfer electrons, and membranes to hold the whole system together.
I came across a wonderful episode of the On Being Podcast with Krista Tippett that featured Janine Benyus, a nature writer who published a revolutionary work on biomimicry — the emulation of natural systems by engineers and designers. Natural systems that had millions or billions of years to evolve and hone their skills.
Thinking back to her precise observations of nature while wandering through the EcoLab, I can’t help but agree with her. Our planet is truly skillful and knowledgeable and I hope we can copy enough to be good stewards of it.
