Many loose ends but hopefully you get the idea cluster.
The aquaculture suggested could be done onshore next to the ponds and linked into the water supply to the ponds for nutrient reclamation - just like in an aquaponics system.
A new BECCS kiln would be needed to process microalgae waste biomass and provide power to the DAC.
The PV printing could be done on site from a shipping container operation (powered from the BECCS) to expand the DAC system as needed for pond expansion. Maybe add a CO2 battery being trialled in Sardinia, Italy.
Alternatively, a 'new material', as previously blogged, could simultaneously harvest and store sunlight to power the DAC 24/7.
I don't think this spells the end of agriculture. Excess biochar could be transported to agricultural sites as needed. Plus, there are all the other materials and industries that can integrate the biochar.
There's also a possibility of onshore macroalgae/kelp (in keyline ponds for greater depth and less evaporation) but probably better farmed in the ocean though logistically may be more work compared to onshore microalgae production but it ultimately depends on what products you want from a given species, microalgae or macroalgae (and there are many!), and where and how those species are most appropriately grown.
Above is a small-scale system for microalgae protein or for whatever else you can grow and extract! The smallest size would be a minimum of 2 IBCs for water, mineral and nutrient reclamation (flip flopping between the two IBCs) and could be scaled up indefinitely. Other food and medicine could be grown in a Regenerative Agroforestry System (RAS), which is also an area I'm R&Ding and documenting on this website. The above system, with the RAS in the future could be an appropriate Carbon negative Vegan food and medicine system.
Here's another option for small-scale microalgae production using the mainframe of the Permachar Kitchen Garden (PKG). In this array there is more surface area per water volume compared to using IBCs. Biochar could also be used in the base for water filtration. Harvesting could be done by scooping off the microalgae with a swimming pool leaf scoop (or something else). The outlet holes would also need to be plugged.