Regarding the artic warming, we have to remember that correlation does NOT equal causation. I think that's one of the major mistakes made by "alarmists". Especially since the research shows worse correlation with more extreme warming. This is the type of "messy" science that is genuine. Though the type of thing that is unlikely to gain much funding because it's not "sexy" enough.
The oxygen in River flow seems kinda like junk science to me. We know gases can dissolve in water. We know that effect changes with temperature. We can plot that effect. With colder temperatures resulting in the solvent being able to retain MORE solute. Plot those graphs. Study concluded for how this could be affected with higher vs lower temperatures. Not sure why they treat this as something so mysterious that they can't study it in a lab have have to completely rely on field readings. LOL.
Now, the flow is obvious as well, you agitate the water and you get more gas exposed to the water and more gas dissolves. Though that would be a function of temperature as well.
Not sure why light is supposed to be an important component. But,
