Ocean acidification: how climate change is affecting our oceans.
Sat, 17 Jan 2009 1:34 pm – Posted by Kirstie_Knowles | 15 Comments
While the impacts of climate change on land are hotly discussed, its effect on our oceans and marine life tend to fall into the ‘out of sight out of mind’ black hole. Yet the effect of increased carbon dioxide levels in our atmosphere is likely to have significant impacts both on our marine life and on us - our society and our economy.
Our oceans are one of our most important carbon sinks – absorbing around a third of the carbon dioxide (CO2) emitted by burning fossil fuels. When CO2 is dissolved in water, a new compound is formed – carbonic acid. High concentrations of carbonic acid can have effects on other compounds in our waters – calcium carbonate being one of them.
Much of our marine life depends on calcium carbonate to grow, provide shelter or protection. Just think of our shellfish & crustaceans - mussels, crabs, oysters, crayfish, paua – their shells are all composed of calcium carbonate.
Calcium carbonate forms the building blocks of some of our most important biological life forces in our seas – such as plankton – which are comprised almost entirely of calcium carbonate. Plankton essentially plays the same role as our forests on land, by absorbing CO2 and converting it to oxygen. Without these tiny plants, marine food chains would collapse and the available oxygen in our atmosphere would diminish.
As more and more of the carbon dioxide we pump into our atmosphere is being absorbed by our oceans, our seas become more acidic, causing this calcium carbonate to break down.
Scientists have named the phenomenon ocean acidfication. While the current detected change in ocean pH appears minor (just 0.1 pH units), it has been predicted that by the end of the century, our ocean pH will have declined by 0.4 pH units and the available calcium carbonate will have declined by 60%.
So what does this mean exactly? In a nutshell, it means that the homes, bodies and life support of much of our marine life will diminish (see the video below for more on this).
As well as a reduction in calcium carbonate, marine life could suffer directly from the effects of more acidic water. For example, it would affect the immune responses of fish. Their metabolism, behaviour and reproduction may also change. The acidification of our oceans could change the availability of food in our seas & break down important food chains, affecting our larger marine mammals such as dolphins and whales.
So are we really going to let the seas dissolve before our eyes? What are some of the solutions? And how can you and me make a difference?
That’s scary stuff. I studied chemistry for four years (at high school), but for some reason it has never dawned on me how pumping Co2 into the air would completely change the make-up of our oceans.
The media tends to forget or overlook that climate change causes direct effects on marine and other biodiversity in ways other than just by changes to sea-level. It’s good to be reminded. Good, but scary!!!
A National Geographic magazine left me with the distinct impression that the continued loss of river water through irrigation etc resulted in less lime reaching the sea reducing the ocean’s ability to sequester carbon.
I am no scientist so would welcome comment. With most major(and many minor) river systems severely depleted by the time they reach the sea it seems logical to assume that something must be affected apart, as we already know,from ecosystem health.Nutrients brought down to the estuaries by natural river flows(big and small) are vital links in the chain of marine life.
I continued to be annoyed and frustrated by the comments from those who should know better, that any river flows going out to sea are ‘wasted’.
Adding sewage, fertilizer and other waste to our receiving waters must also be compromising the ocean’ s ability to sequester carbon.
The miracle is how long it has managed to continue doing it.
We continue to reduce river flows at our peril.
Thanks for a good blog on this issue Kirstie. It’s a very worrying scenario with huge ramifications. I was listening to Obama today reminding us all that the power of people to change the world should not be under-estimated. This is a global issue that NZ could take a lead on via F&B. Kia kaha !
Good point Chris.
Whilst not an expert on carbon sequestration in the ocean, it would indeed seem logical that increased turbidity - suspended sediment in the sea - would lead to reduced plant life (i.e. algae or phytoplanton) available to use carbon. Becuase most plants need good light to live.
That said, some pollutants do not necessarily increase turbidity. Some inject nutrients that increase plant matter - algal blooms. In this situation perhaps, more carbon could be sequestered. The impacts of that increased plant material on the wider ecosystem however are another matter. What we are currently putting in our rivers is making a difference to life out at sea - that’s for sure.
Out of interest, there have been some scientists that have been barmy enough to even propose artificial fertilization of photoplankton in our seas for the purpose of increasing CO2 absorbtion. The theory being that as we would encourgae more trees to be planted, so more phytoplanton in our seas could address global climate change. Thankfully, or at least I think so, several international and intergovernmental scientific groups have developed position statements warning against this practice.
Check out the ocean acidification network for more information:
http://www.ocean-acidification.net/
150 top marine scientists just signed a declaration warning of ocean acidification. Check out BBC press release:
http://news.bbc.co.uk/2/hi/science/nature/7860350.stm
[...] And with many more eyes on our quickly deteriorating coral reefs (a side effect of ocean acidification), this tool may have the power to open people’s eyes to the effects of climate change on our oceans [...]
Another new paper published in the Science journal proposes that fish may play a very important role in balacing out the degradation of calcium carbonate in our oceans:
http://www.thefishsite.com/fishnews/8870/study-fish-maintain-vital-ph-of-oceans
What do people think?
So overfishing could accelerate the acidification of our oceans, in turn breaking the whole system down. It’s just another argument for more fishes in our seas!
I’ve just checked out the BBC website Kirstie referred us to regarding the Monaco Declaration
There is an urgent need to rehire Al Gore or equivalent to highlight the dire ramifications of acidification of the oceans
because we really don’t know what lead time we have to avert disaster
What about a campaign around fishless fish and chips- striking a the core of what it means to be a Kiwi !?
It’s like every other environmental concern- to make it up close and personal as well as finding easier ways to do the right thing .
Like the fish-less fish n chips idea - a great image springs to mind! As well as factoring in ocean acidification, we’re also got to look at the warming of our oceans. Recent climate change models - http://www.mercopress.com/vernoticia.do?id=16118&formato=HTML - predict that many fish will head pole-wards with the warming of our seas - completely changing the make-up of our oceans.
Do we know the source of calcium carbonate in our oceans?
My impression from the National Geographic article was that a proportion of it was sourced from the limestone many rivers cut through on their way to the the ocean and that any lessening of the flows through abstraction lessened the amount of lime able to be transported to the sea for, amongst other functions , sequestering carbon dioxide.
It would be good to know what the sources are as that could inform our decisions on setting river flows in the future.
New papaer publiched in American Scientist suggests that ocean acidification from CO2 may be happening faster than we thought.
check out the article at: http://www.sciam.com/article.cfm?id=ocean-acidification
The results are in - fertilization of our oceans will make make little difference to limit the effects of climate change.
The results of the controversial German study - conducted in the Southern Ocean - illustrates that ocean fertilisation is not the answer.
However, it seems those seeking to do anything and everything not reduce our emissions are determined to continue along this potentially disasterous path.
For more information see:
http://news.bbc.co.uk/2/hi/science/nature/7959570.stm
Until countries and people see a reward for doing the right thing-reducing emissions- these futile activities will continue.
The rewards need to be saving money, or making money and a change of emphasis by governments away from dependence on finite resources .
The fact that by doing so we save ourselves from poverty, environmental degradation , famine, war and possible extinction is the icing on the cake.
In the new era of financial accountability triple -bottom line accountancy has to be practised. Only then will we get away from the Exon Valdez -type of GDP where cleaning up a toxic spill or other disaster is good for the local economy!