Ocean Acidification is the wrong meme for the toll high and rising CO2 takes on our oceans.
Acidification won’t cross the boundary from today’s basic ocean (pH ~8) into a deadly acid one (pH ~6) for centuries.
So if you want to give the climate change denialists a free win keep using the term ocean acidification.
Today’s tragic truth is already the amount of yesterday’s CO2 in the oceans has already shifted a delicate and vital solubility balance that much of ocean life depend on.
Published today in the journal Nature Climate Change a paper defining Risk maps for Antarctic krill under projected Southern Ocean acidification, warns that as CO2 dissolves into oceans immediately making minerals more soluble means, krill and all other life forms that need to take minerals out of the water will collapse.
The scientists in Australia reported on their ocean CO2/Krill models that revealed that enormous declines in krill in the Southern ocean region will occur within the next 100 years, they will be all gone within 200 years. This foreboding future will result in catastrophic consequences for dependent marine mammals and birds of the Southern Ocean. Their study is based exclusively on ocean acidification.
Krill is one of the most vital components of the food chain in the region and courtesy of the Disney Movie Happy Feet is well known as being a key food for penguins, seals, fish and whales.
The new report comes with the endorsement of 24 countries and the European Union that are gathering in Germany for a special meeting to consider proposals on how to sustainably manage the seas around Antarctica. What is most vital is that this group adopt measures that will restore those seas to historic health and abundance from the terribly diminished state they are in today.
This recent study, carried out by scientists at the Australian Government’s Australian Antarctic Division (AAD), has found that once levels of dissolved carbon dioxide in the ocean reach about 1250 microatmopsheres, the numbers of krill eggs successfully hatching decline dramatically. Some of the areas for krill today already reach 550 microatmospheres. We know with certainty that already the Krill are in trouble, the whole world will be sorry one day if we allow them to perish.
Why Ocean Acidification Is The Wrong Meme – the CO2 threat to ocean life is not about acid it is about solubility
Minerals in the ocean, especially calcium but many others as well are vital for most of ocean life. Calcium in the ocean is mostly in a delicate balance between its chemically bound state as calcium carbonate and free calcium ions. Yeah, I know this sounds like science but stick with me you’ll get it immediately. The story of solubility is simple to absorb.
Think of things you know as being easily or less easily dissolved in water. Take sugar for example, if you have really cold water and put in a spoonful of sugar it dissolves very slowly, but if your water is hot the sugar dissolve really fast. The HOT water make the sugar more soluble. So imagine you put too much sugar into your cup of water, you might with cold water quickly pour most of the water out of the cup before it became too sweet, this is because the solubility is low. But if the water is hot you are out of luck, the solubility is high and you have no hope at all of keeping some of that sugar undissolved.
Today’s deadly shift in ocean mineral solubility
With Krill and myriad other forms of tiny ocean life they all begin their lives as microscopic drifters, plankton. As tiny tiny life if they need calcium, and they do to make their shells, they need to extract that calcium from their water. If the calcium is not very soluble the critters are in luck they can get it easy.
If their vital calcium is very soluble, which CO2 is making it so, the tiny life forms have to expend an inordinate amount of energy to extract their vital calcium, and other minerals, out of their water. So right off as soon as you hatch in your weakest most vulnerable stage of life you are in big trouble if you have to spend most of your meager supply of food/energy to get enough calcium to make a microscopic thin shell to protect yourself.
In the real world of today the crisis of our trillion tonnes of CO2 already emitted into our air over all of our yesterday’s of the fossil fuel/fool age is that our CO2 has been dissolving into our oceans. Some places like cold oceans, aka the Southern Ocean or the North Pacific more than warm tropical oceans, solubility of CO2 goes down as the temperature goes up, the opposite of sugar and water.
Here’s who suffers from TODAY’s CO2 reality which is entirely due to YESTERDAY’s CO2. It’s the baby life forms, in this post case we are talking about KRILL.
The immediate consequence of this study is to show that if we want to minimise the chances of major collapse of ocean pasture ecosystems disruption then future emissions will need to be moderated from the current trajectory, but even more importantly Yesterday’s CO2 burden, the trillion tonnes already emitted needs to an immediate antidote.
Australian Antarctic Division scientists captured and took krill back to the government laboratories in Hobart, Tasmania, to mature. There, tanks were set up to recreate different concentrations of CO2 in ocean water and the krill were allowed to spawn.
In Antarctica when mature krill spawn, their eggs sink to depths of between 700 and 1000 metres where they hatch in about a weeks time. The hatchlings then swim back up to surface ocean, the ocean pastures, to feed and mature.
But the study dosed the krill in the ‘fish tanks’ with higher and higher concentrations of CO2. This caused the krill eggs to develop more slowly They sink very slowly into the depths as they are incubating meaning the more time they are sinking eggs the deeper they sink. That’s new knowledge about how CO2 impacts krill.
As soon as sinking krill eggs hatch the hatchlings start swimming and start immediately back to the surface. They are very tiny so it takes them a long time to make that trip up. They have only limited energy stores and they need to make it to the surface to find food. But delaying their development means they sink deeper and have to swim further to get to their nursery pasture. We don’t fully understand yet the capacity of those larvae to extend that vertical migration.
In other words, the krill might just run out of their energy stores before they get back up to shallower depths.
The study raises some questions about the krill – and their ecosystem – to withstand multiple changes such as warming ocean temperatures and increased krill harvesting.
Commercial fishing, regulated by the Commission for the Conservation of Antarctic Marine Living Resources, is currently pulling about 200,000 tonnes of the crustacean krill from the Southern Ocean around Antarctica, mainly from areas around the Weddell Sea. The krill is used in a large array of products, health supplements and as feed for farmed fish.
The study came to the conclusion that unless greenhouse gas emissions are cut dramatically, these same areas currently being targeted for krill would be the same areas where krill hatch rates would begin to drop in 100 years time. Mr King said AAD scientists were now studying how krill react when you have more acidic oceans combined with these changing temperatures.
We can and must restore the ocean krill pastures of the Southern Ocean.