People often mistakenly think that the sea is blue because it reflects the sky, but the truth is that pure water is very slightly blue. It is just so pale that in small quantities it appears clear.
Fundamentally, what makes water blue is the fact that it absorbs light that is red, yellow and green, and scatters light that is blue ─ this is because blue light travels as shorter, smaller waves that are scattered more easily (this is essentially the same reason why the sky is also blue). The reason a small amount of water appears clear is because not much light is scattered. In larger bodies of water there are more water molecules for light to collide with, resulting in more blue light being scattered. Think of it like throwing a bucket-full of tennis balls against a tree from a distance: the chances are that most balls will miss the tree and keep going. But if you stand in a forest and throw tennis balls, more balls will hit trees and bounce back. It is exactly the same when it comes to light hitting water molecules: if there are more water molecules in the way, more light particles will collide with them and be scattered, making the water appear a deeper shade of blue.
Imagine that all of the water in the oceans evaporated, just leaving the salt (sodium chloride) behind. Now imagine that you gathered up all that salt and spread it equally over the Earth’s land surface (perhaps with a little help from a few million other people). How deep do you think that layer of salt would be? One estimate is 500 feet, or just over 150 meters!
For the last year, I have not been publishing many blog posts. I can now reveal that the reason for this is not laziness (at least not entirely), but due to the fact I have been writing a book about the oceans. The book is called “Do Fish Sleep?: and 38 other ocean mysteries” and it is available to buy for kindle* via Amazon for a very reasonable price ($2.99 in the US, £1.99 in the UK, and EUR 2,99 in Europe). Over the next few months I will be publishing the entire first chapter of the book (Ocean Secrets), one “ocean mystery” at a time, on Words in mOcean, starting tomorrow with “Why Is the Ocean Salty”. It is my hope that you will enjoy what you read and go on to buy the full copy of the book. For more information, please read the “preface” below or visit the Amazon page.
*To read it, you do not need to own a Kindle device, just the Kindle App which is a free download for smartphones or tablets. It can also be read with “Kindle Cloud Reader” on a PC or Laptop.
Whether you are on a boat trip or cruise and want some appropriate songs, or whether you just want to imagine that you are out at sea whilst in the office or lab, we have some tunes for you. Below are 16 of the best ocean songs out there, including some beauties from The Beatles, The Beach Boys, Frank Sinatra and Led Zeppelin.
If you are sat in a cold bath and turn on the hot tap, what happens? The water close to your feet becomes unbearably hot and the water near the top half of your body doesn’t noticeably change temperature. Fundamentally, the same process happens in the oceans. The sea nearest to the equator heats up as it receives the highest amount of energy from the sun; the sea nearest to the poles generally loses heat. In the bath, you slosh the water about as it enters the tub to distribute the heat more evenly. In the oceans, currents perform the same job, helping to move heat from the equator to the poles and make higher latitudes more habitable. If, for some reason, the currents transporting heat to higher latitudes slowed, the effect would be similar to you not mixing your bath water. Your feet (the equator and tropics) would become hotter, and your body (the subtropics and poles) would become colder. This is exactly what scientists think they observed in 2009/2010 in the North Atlantic, and they think this may explain some of the freak weather that was observed during that period.
In survival situations people often talk about the rule of three. It is said that humans can only survive for 3 minutes without air, 3 hours without heat, 3 days without water and 3 weeks without food. Not wanting to be left out, it seems that some phytoplankton also obey a rule of 3 according to a new study: they can survive for 3 weeks without key nutrients such as nitrogen and phosphorus.
DEFRA report shows the massive pressure that is being put on UK marine science by commercial interests: from setting the research agenda, to running public services for profit, and the desire to dismantle public bodies such as CEFAS and the Met Office.
Think of an extreme environment where life survives in the ocean. What springs to mind? The mind boggling pressures and eerie quiet of the deep-sea perhaps? Maybe the icy environments at the poles? Possibly even an estuary, where organisms are flung from one salinity extreme to the other on a daily basis. There is another extreme environment though, one which few of you probably even considered, one that covers about 30% of the planet and is currently expanding under the influence of climate change: large swirling systems of rotating currents that occur in the centre of oceans known as subtropical gyres. Continue reading Ocean Deserts: it’s a hard life in the tropics, but not if you’re small→