It's sad that the effort to do something innovative to solve a problem can easily get dismissed via a zero effort critique by someone who never took the time to learn why it was created.
There is a tree right next to it. LOL so obviously space for trees. The trunks take up less space, its just they require pulling up surrounding sidewalk sometimes, and maintenance crew for trimming and watering in dry spells.
Trees don't perform nearly as much work as the algae tank in sucking up C02 and outputting 02, require more maintenance, and takes longer to deploy (have to wait for tree to mature).