Ocean acidification ... now that's gonna sting

Credit: pixabay

Into week three of my Future Learn/University of Exeter (which looks like such a wonderful place to study) course on Climate Change: The Science, and this week we've been looking at the oceans and wondering what those beautiful clownfish ever did to deserve what's being thrown at them, climatically speaking.

As I write this, I'm eating Raffaello chocolates from Ferrero Rocher, and wondering where all the plastic that consumes* them is going to end up.

"Ambassador, with these Ferrero Rocher you are really spoiling the ocean" 

OK, three questions to answer:

1) What is the effect of acidification on marine organisms? 

Now, marine organisms is quite a broad term. Big fish, little fish, probably a cardboard box or two as well.

So first, a quick explanation of ocean acidification (OA) as I understand it. Humans have been releasing a lot more carbon dioxide into the atmosphere over the past 200 years than the Earth has been accustomed to. About 30% of this has been absorbed by the oceans. This is good (at least in the short-term), as it has kept a rein on global warming on land.

However, the high levels of CO2 in the seas are causing a chemical shock for many of the creatures that live there. Mixing water and carbon dioxide allows carbonic acid to form. Acids release hydrogen ions. Hydrogen ions are flirtatious little sods and want to get hooked up with anything going. One of the things going is carbonate.

But carbonate is much in demand as marine organisms use it to make shells and skeletons. As carbonate heads off into the sunset with hydrogen ions, (in the form of biocarbonate), certain marine organisms are left feeling a little, well, naked. Lazy. Fed up. Basically they have to spend a lot more energy on making their shells, leaving less for eating, reproduction and growing properly. They mope, essentially.

One of the major problems is that a lot of these carbonate-dependent organisms are at the bottom of the food chain. If they become fewer in number, or smaller, that causes problems for marine organisms higher up the food chain. Fish people might care about a bit more, perhaps.

Other reported impacts of OA include reducing the smells, sights and sounds of the oceans, which can affect marine organisms' ability to find habitats and food, and escape predators.

I should point out that some marine organisms are likely to thrive in a CO2-richer environment. But it'll probably be the ugly ones, or the really rubbish ones that are essentially plants anyway, not the pretty tropical fish.

2) Are there any economic effects from your chosen impact? Which areas might be hit the hardest? 

Early days. In fact, the study of OA as a whole is rather nascent compared with other aspects of climate change. Heck, the Guardian doesn't even have a keyword for it yet! So direct economic impacts are hard to predict. However, fish is a vital source of protein for millions of people - constituting 70% of protein intake for some island and coastal countries, according to the Food and Agriculture Organisation. Declining fishing stocks would have a severe impact on food security and on people working in the fishing industry. And some of those people - those who can afford it - will turn to meat as a protein source, and increasing meat demand could produce a positive feedback as many sources of meat (particularly cows) contribute to global warming (by farting and deforestation).

3) What’s the most effective solution to preventing your chosen impact? 

There is emerging evidence that growing more sea grass could help, by absorbing marine CO2. A bit like planting trees on land. Limiting consumption of affected species of fish by those who can, while not directly changing the pH balance of the sea, could allow those species under most stress a greater chance to adapt or recover. But, in a nutshell, we need to stop releasing so much CO2 into the atmosphere. Simples...

Additional sources: Simthsonian, WWF, NOAA

*OK, so it's actually me consuming them.