"Herring could actually benefit from ocean acidification"

"Here at Pangloss Group we look on the bright side..."

From Ars Technica March 25, 2018:

The effect is indirect; the increase in CO2 increases herring’s food supply

Species don’t live in isolation; they live in very tangled, complicated, interconnected webs. So studying them in isolation has only limited utility, much like studying cells cultured in a sterile petri dish. These laboratory studies can yield suggestive and promising results, but these results are not always applicable to how the cells behave in the context of an organism, much less as part of a species in an ecosystem.

The increased carbon dioxide that humanity has been relentlessly pumping into the air since the onset of the Industrial Revolution is acidifying the oceans. Studies done to determine what this ocean acidification will do to fish have mostly assessed the direct effect of elevated CO₂ levels on the fishes’ growth and physiology, but they have not taken into account any effects ocean acidification might have on food webs as a whole.

Scandinavian marine biologists have tried to rectify this situation by studying the effects of ocean acidification in 10 mesocosms—fiberglass tanks seeded with rocks, sediment, plankton, and other microorganisms—they set up off the west coast of Sweden. Five were controls; the other five got elevated CO₂, set to mimic levels that the Intergovernmental Panel on Climate Change calculates could occur by the end of this century. Those estimates are about 760 μatm (short for micro-atmospheres) pCO₂, compared to today’s 380 μatm pCO₂). Being Scandinavian, these researchers examined the survival of... herring.

While the phytoplankton in the mesocosms were blooming, in mid-April 2013, the researchers added fertilized herring eggs to all 10 of them. Significantly more herring larvae survived in the five with the elevated CO₂ levels than in the controls, especially during the critical first feeding period just after the eggs hatch. This was a surprise, given that high CO₂ levels had negative effects on herring larvae in laboratory studies....MORE

Tomorrow, a more serious look at our friend, the cod.