chroniclesofeverything

Climate Change, Ocean Change

Posted on: June 6, 2012

So I’m at uni right, and I’m doing a degree that lets me take pretty much any subject I want. It’s wonderful, but makes trying to keep up with my electives kinda pointless… Anyway! One of my subjects this semester is Marine science. One of our lectures was on the effects of climate change on the ocean. I always thought that I had a pretty good handle on oceanic climate change. Climate change=rising sea levels. That’s all there is to it, right? Wrong.

As part of my super studious swotvac revision (read: productive procrastination) I wrote an article about it, that was posted on Student View. I’ve put it in below too. And now that I’ve got two weeks before my next exam, expect me to actually post here 🙂

Climate Change: The Oceans Will Do More Than Rise

 Everyone’s heard that the sea levels are rising, but there are plenty of oceanic effects that are currently being ignored. The ocean plays a major role in the carbon cycle, storing 93% of the carbon on earth. What this means is that as we unbalance the carbon cycle we put both terrestrial and marine ecosystems out of balance as well.

The ocean is separated into two layers: surface ocean, and deep ocean. The simple way to think about it is that the surface ocean is warmer, and the deep ocean is cooler. Makes sense, right? Light doesn’t reach the deep ocean, so it doesn’t get warmed up, and because it’s cooler, it’s also denser, and sinks to the bottom. The deep ocean holds most of the nutrients (they sink) and most of the CO2, since CO2 is more soluble at colder temperatures.

With increased CO2 in the atmosphere, more is going to travel into the surface ocean through dispersion. Unfortunately, if the ocean warms up by even a degree, the new CO2, and some of the CO2 already stored there, will separate out of the water. This will be due to the reduced solubility of COat higher temperatures. There’s a high chance that in the future CO2 will be emitted by the ocean, into the already suffering atmosphere.

Nutrients in the ocean will also be affected. People have argued that since sea organisms need CO2, increased levels of atmospheric carbon will actually increase their growth. Don’t get me wrong, I’d like to believe it, but as the facts stand, CO2 isn’t a growth-limiting nutrient. There’s plenty of it down there already, and no matter how much more you give them access to, the organisms still won’t have enough iron, nitrogen or phosphate to grow at a faster rate.

We’re not positive yet whether climate change is going to affect the supply of those nutrients positively or negatively. On the one hand, most of them are in the deep ocean. The more the surface ocean heats up, the bigger the temperature difference between the surface and deep ocean, and the less mixing between the two will occur. Mixing is how marine organisms get those sunken nutrients back into play. Of course, another climate change prediction says that we will have more storms in the future. Storms can do significant ecosystem damage, but they also help mix the surface and deep ocean, and reduce stratification. The jury is still out on this one!


The final, and most depressing aspect of the marine ecosystem is a direct result of elevated CO2 levels, not climate change. This means that even the climate sceptics out there, should be worried about this! In the oceans there’s currently balance between CO2 and CO3. 25% of the CO2 humans emit enters the oceans, and that pushes the balance towards CO2 and away from CO3 (and makes the oceans more acidic.). The main problem with this is that CaCO3 is used to make a lot of the shells, scales and skeletons of marine organisms. With decreased amounts of CO3 available, organisms that use CO3 in their bodies will be put under increasing stress. Coral especially will suffer and become less competitive, but so will molluscs and pteropods (a type of planktonic snail).

No one wants to lose the beauty that the oceans offer us, but can we act in time to prevent the damage already being done?

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