• Jessica Evans

The ocean: what's the big deal?

Okay so there's a big fuss about conservation at the moment, particularly the conservation of the world's oceans. But really, what's the fuss about? Why is the ocean so important?

Well, for many reasons. The reasons that first come to mind are pretty human-oriented. The majority of the world's human population lives within 50km of the coastline, so we have, and always have had, a huge link to the sea. We rely on it for recreation, food, employment, tourism, and travel. It's been estimated that the ocean has an annual worth of $22 trillion. So a lot rests on the well-being of the ocean when it comes to humans.

Apart from all this, the ocean plays an immense role in the functioning of our planet as a whole. It plays a role in heat distribution and regulation, weather systems, and the circulation of water, nitrogen, and oxygen. What I want to discuss in this post, however, is the ocean's role in the carbon cycle. Chemical elements are types of atoms and carbon is an element. The carbon cycle is the earth's mechanism for drawing carbon from carbon dioxide (CO2) out of the atmosphere. Because CO2 is a greenhouse gas, it helps keep the earth warm. Too much of it, however, is just plain bad. If too much CO2 accumulates in the atmosphere, the planet will get very, very hot, and life (at least the life that breathes oxygen) on earth will eventually disappear.

Just the surface of the sea contains 50 times more carbon dioxide (CO2) than the atmosphere! So you can imagine that it plays a massive role in what happens to all this carbon.

The ocean has two ways it can recycle this carbon so it doesn't just sit there. The first is a long process called the solubility pump, also known as the physical pump. It can take hundreds to thousands of years and it accounts for about 95% of carbon cycling. This means that even if we stopped all carbon emissions right now, the effects would only manifest after at least hundreds of years have passed. The solubility pump works when the colder surface waters nearer to the poles are subducted to deeper depths. This happens because colder waters are denser than warmer waters so they sink - kind of like how hot air rises and cold air sinks. This means that these carbon rich surface waters sink, taking all the carbon from the surface to the deep waters of the sea.

The second method the sea uses to get rid of stagnant carbon is the biological pump. This pump uses the living creatures in the ocean to recycle carbon. Phytoplankton are tiny microscopic plants and, just like plants we know on land, they use carbon to turn into food to grow. The biological pump also uses the dead cells of sea creatures. When these cells sink, they're contributing to the carbon cycle. This is because every living thing has carbon in it's make-up.

It's role in the carbon cycle is just one more thing that makes the ocean so cool. The problem, as is with many, many, other things, is global climate change. As the ocean gets warmer, the solubility pump doesn't work so well. It relies on cold surface waters in order for the carbon on the surface to sink, so it becomes less effective and the carbon hangs around, reacting with the water and turning into carbonic acid. So the ocean is becoming warmer and more acidic, which doesn't look too good for the organisms that live in it - think coral bleaching.

Another problem, linked to climate change, is the accumulation of CO2. We are emitting so much carbon, and at such a fast rate, that the pumps aren't keeping up. The atmospheric concentration of CO2 is currently about 400 parts per million - the highest it has ever been. The primary culprits responsible for this CO2 build up, the increase in other greenhouse gases, and the increase in temperatures, are deforestation, industrialization and the farming of cattle and rice. If CO2 concentrations keep increasing, and the carbon cycle loses its efficiency, global warming will hasten, causing the ocean to become warmer, which in turn decreases the efficiency of the carbon cycle. So the whole thing basically spirals out of control.

But fear not! It doesn't have to be all doom and gloom. We can each take tiny steps that might seem inconsequential, but do actually make a difference. Plant a tree or three. Be mindful of how you travel and commute. Consume less beef, or less rice. Be creative. And spread the word.

#ocean #globalwarming #climatechange #carboncycle #greenhousegases #co2 #emissions

©2018 by Bite-sized Sci | Jessica Evans