As carbon dioxide builds up in the Earth’s atmosphere, carbonic acid builds up in the oceans. Because of the carbonic acid, oceans are becoming more acidic. Elizabeth Kolbert at the National Geographic explains how oceans acidify and asks whether oysters, mussels and coral reefs will survive.
Acidification is bad news for all marine organisms but it’s worse for some than others. Trevor Branch at the University of Washington tells us about evidence that commercially targeted fishes and shelled molluscs will be damaged more than cephalopods and crustaceans.
Some people here eat fish including cod and salmon. Some people eat shelled molluscs including oysters and mussels. Some people eat cephalapods including squid and octopus. Some people eat crustaceans including crabs and lobsters. I wrote here about wild cod and farmed salmon, about wild oysters, and about wild crabs, mussels, octopus and cuttlefish.
From Prof Branch’s review, it seems that we might expect acidifying oceans to damage cod, salmon, oysters and mussels, but to be less damaging for squid, octopus, crabs and lobsters. The story is complicated because species interact with one another. They form food webs. For a marine example, here’s the Great Barrier Reef’s food web.
In the sea, everything depends on everything else. The international marine conservation body Oceana predicts that acidification will have rippling consequences throughout the entire ocean. My fellow blogger Beach Chair Scientist invites us to consider sustainability in the USA’s National Seafood Month. Another of my fellow bloggers, Eivind Burkow at The Coastal House, tells us about warnings of global food insecurity as climate change destroys fisheries.
I’ve written about how fish farming (aquaculture) might offer good ways to feed people. Some fish farms use cages in the open sea but others use closed ponds or tanks. In closed systems, acidity is controlled by the farmer (scroll down for the section on water quality). Mr Burkow tells us about developing systems for shellfish aquaculture. I think aquaculture might offer a way around the food implications of acidification. In a technical sense, that is. Whether or not it’ll make good business sense is another matter.
I’ll finish by recommending the WP blog Ocean Acidification. I wanted to link to several of Lina Hansson’s recent posts there, but the links didn’t work today. Do take a look, though. [Edit a few days later] The link’s working again here.