[acyou]

Algal blooms with limited mixing sounds like a pretty good carbon capture mechanism!

I wonder if there is oil and gas at the bottom of any of these deep lakes? /s

It would be interesting to know the gas balances for these lakes, in particular how reduced mixing affects methanotrophy and methanogenesis. If its talking about climate change, this article really should discuss methane, I think that's a bigger deal.

[dredmorbius]

This is a mechanism by which some oil deposits are thought to have formed, and by which a large quantity of biospheric carbon was sequestered during earlier warm spells, refered to as the Eocene Azolla Event.

Essentially: arctic seas formed fresh-water "lenses" through meltwater, which promoted plant growth (in particular azolla, though likely also algae and plankton). This growth then sank to the sea-floor, depositing as oils (and much ultimately undergoing keroginisation to form petroleum).

<https://en.wikipedia.org/wiki/Azolla_event>

Similar mechanisms have been proposed for addressing carbon sequestration goals in the present, e.g., "CO2 sequestration by propagation of the fast-growing Azolla spp. " <https://pmc.ncbi.nlm.nih.gov/articles/PMC8520330/>.

[maxbond]

It could also be the opposite of a carbon capture mechanism is the detritus if those algal blooms are broken down by archaea and turned into methane, which could then return to the atmosphere. Methane is about 30 times more potent a greenhouse gas than CO2.