Only with recent (over the past 100 years) have we seen large-scale losses in phytoplankton levels in the oceans
I have not seen any reconstructions of such. I'd like to seem some, and also have at least a rough understanding of how well they have been vetted compared to temp reconstructions. All the controversy in temp reconstructions does have the effect of making them better researched. I'd take any claims of large scale phytoplankton changes with a grain of salt. Not saying it is not the case, but I suspect it is not overly well documented.
Sure.. Phytoplankton take CO2 from BOTH the oceans and the atmosphere.
I can't find any links showing uptake from the atmosphere. I suspect it is all from dissolved CO2.
However, I have found that the ocean uptake of CO2 is very large, much larger than the current biological use, so I now suspect that is less of a problem. The uptake is around 92 Gt/y, but release is about 90.6 Gt/y with a net uptake of only 1.4Gt/y. The problem is that uptake is towards the cooler polar water, and release is in the tropics. So you would in fact seed near the tropics, and rely on transport from the poles, and the magnitude of transport relative to what you are trying to achieve looks fine.
Sure.. Phytoplankton take CO2 from BOTH the oceans and the atmosphere. And the rising acidity of the oceans, and rising CO2 levels in the atmosphere, seem to further the evidence that something is drastically off-balance with oceanic phytoplankton levels.
Why would you conclude that? Humans are pumping 5-7Gt/y into the atmosphere and the ocean net scrubbing is only 1.4Gt/y so you would expect such changes without conjuring up problems with phytoplankton. You have to increase ocean net absorption by a factor of 3 or so to balance out (sans other things helping as well).
The net sequestering to ocean floor sediment looks like it is only 0.2Gt/y, so you really have to kick that one up. I did find one reference out of Princeton saying that Diatoms, which are the best (??) at sequestering the carbon, look perhaps most likely to benefit from higher acidity and higher CO2. But given how low the sedimentation rate is, that really must be raised a lot (factor of 10).
Altering natural systems by a factor of 2 up to 10 or so is very significant, especially if you are talking about something as large as the ocean.
I still think it has promise, but I seriously doubt that it is as simply a solution has some would claim. |
