Discouraging ocean predictions

Equatorial refuge amid tropical warming

From the link:

Upwelling across the tropical Pacific Ocean is projected to weaken in accordance with a reduction of the atmospheric overturning circulation¹, enhancing the increase in sea surface temperature relative to other regions in response to greenhouse-gas forcing. In the central Pacific, home to one of the largest marine protected areas and fishery regions in the global tropics, sea surface temperatures are projected to increase by 2.8 °C by the end of this century^{2, 3, 4}. Of critical concern is that marine protected areas may not provide refuge from the anticipated rate of large-scale warming, which could exceed the evolutionary capacity of coral and their symbionts to adapt⁵.

I am, like George Costanza, no marine biologist, but that does sound like a heck of an increase in sea surfaces temperatures in waters that are already pretty warm.

The article goes on to explain that there might be some compensating upwelling which will cool certain Pacific Islands, but even so the temperatures will be up.  Just not as much.

Sounds like a hot time for many coral reefs.

In another article in Nature Climate Change, some researchers think that increased CO2 will hurt, not help,  phytoplankton, contrary to what you might expect:

Carbon dioxide and light are two major prerequisites of photosynthesis. Rising CO₂ levels in oceanic surface waters in combination with ample light supply are therefore often considered stimulatory to marine primary production^{1, 2, 3}. Here we show that the combination of an increase in both CO₂ and light exposure negatively impacts photosynthesis and growth of marine primary producers. When exposed to CO₂ concentrations projected for the end of this century⁴, natural phytoplankton assemblages of the South China Sea responded with decreased primary production and increased light stress at light intensities representative of the upper surface layer. The phytoplankton community shifted away from diatoms, the dominant phytoplankton group during our field campaigns.

 So how does the increased light happen in future?  This seems to be explained in the last part of the abstract:

Future shoaling of upper-mixed-layer depths will expose phytoplankton to increased mean light intensities⁵. In combination with rising CO₂ levels, this may cause a widespread decline in marine primary production and a community shift away from diatoms, the main algal group that supports higher trophic levels and carbon export in the ocean.

Well, there you go.  More news of the giant climatological and ecological experiment that is underway, and that serious people should take seriously.