Steve's Nature Blog: oxygen

Wednesday, 7 December 2016

Every Breath You Take

I thought that as we walk down the next part of the gully we’d have a look at air – there’s some, look, right in front of your nose. You can’t see, smell, taste or touch it so what exactly is it? Mainly it’s a mixture of two elements (not a compound – they don’t combine together). The two elements are Nitrogen (78%) and Oxygen (21%). The other 1% contains other elements, primarily Argon.

Rosularia serrata

Every breath you take (don’t worry – I’m not going to start singing again) is for the most part Nitrogen, a vital element for us but the problem is; we can’t use it directly. We need plants to do a bit of work for us like this Rosularia serrata here. It can’t use Nitrogen from the air either, it needs help from special bacteria in the soil that use enzymes to convert the nitrogen into organic compounds that it takes up through its roots. We, and other animals, can then take the nitrogen that we need to produce things like essential amino acids from the plants that we eat. When it, and we, die we pass the nitrogen back into the soil for reprocessing by bacteria.

Ferns and Mosses

Air hasn’t always been air as we know it today and if we go grubbing about down there in the dark and damp bits we should find a couple of the major players in the events that led to the breathable stuff that we enjoy today. About four hundred million years ago, when these ferns and later these mosses, were the pioneering land plants oxygen was only running at about 15% but plants, as we know, give off oxygen as a by-product of photosynthesis and over the next hundred million years levels built up to about 35%, an abundance that gave rise to giant dragonflies and things. The rise of oxygen breathing animal life brought the levels back down to a range which we’ve evolved to function in which is about 19-24%.

Darkling and Rosemary Beetles

We seem to have come out into the open air as it were and it looks as if we’re at the head of the oleander highway (see Into The Woods) so we should be able to find some nice insect life in there. We have beetles in abundance. This beefy, black job is the brother of the one we found a couple of weeks back up the valley. That one was Raiboscelis coelestinus with the blue sheen and this one is Raiboscelis corvinus. The other two are Rosemary Beetles, Chrysolina Americana, and they seem to be thinking about expending a bit of energy to make more Rosemary beetles. Which brings me back to oxygen. The reason why it so important to us and all other animals is that we need it to convert glucose into energy in a complex process called catabolism^[1]. Simply put, we couldn’t move a muscle without it.

Ant nursery

Apart from the composition of air there are two other aspects of it that are important and those are its temperature and humidity, a delightful illustration of which you can see by looking under this rock that I’ve just turned over. The little white cocoons that the ants are fussing over are the larvae. These, along with the eggs, they constantly move from one place to another within and just outside of the nest to regulate their conditions as the temperature and humidity fluctuate throughout the day and night. They really are the most dedicated of nursemaids. But now it seems we have reached a defile through which we cannot pass, not without ropes and crampons anyway. I suggest that we walk back over the hill, down through the village of Agios Ioannis and pick up our route again a couple of hundred feet lower down.

Cumulus and Cirrus clouds

Just look at that wonderful cloudscape above us. The large, fluffy one is a cumulus cloud (from Latin, meaning heap) while the streaky ones above are cirrus (from Latin, meaning a ringlet of hair). There are sixteen major cloud types in total, all of which contain water vapour in varying amounts evaporated from the Earth’s surface. You may be wondering; if air is 78% nitrogen and 21% oxygen how come your hygrometer says that its 60% water? Firstly it’s because those percentages are for perfectly dry air and secondly that your hygrometer is measuring relative humidity; the partial pressure of water in the air compared to what it could be if it was fully saturated, and not the actual amount of water in the air. Which is a good indicator of whether it is likely to rain or not and thus of far more practical use as a measurement.

So that’s air, in a nutshell. Meanwhile I think I can see the village below us so we’ll explore that next week.

The Extra Bit

Last week’s marmalade recipe seems to have gone down well so I may well do another in the New Year. Meanwhile if you want to know more about how we convert the sugars in the marmalade into energy then you can read all about it here: ^[1] https://en.wikipedia.org/wiki/Catabolism

I've just started a magazine called The Nature of Crete on Flipboard. Eventually it will not only contain links to the latest blog but other articles and blog posts about the flora and fauna of the island. If you'd like to read it and maybe even contribute a link then this is the web address: The Nature of Crete

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LINKS:

Naturalists (the facebook page that accompanies this blog)

See detailed pictures at http://www.inaturalist.org/login (search - people-stevedaniels-observations)

Cretan Flora

The Nature of Crete (Flipboard Magazine)

Flowers of Crete;

BIRDS OF CRETE

Crete Birding

Greek Butterflies and Moths

Aquaworld Aquarium

Visit Greece (National Government Tourist Office)

Wednesday, 23 November 2016

How To Get Blood Out Of A Stone

Ok folks, our mission for today is to clamber down through these rocks and explore that gully down there. To make things more interesting our route is lined with plenty of spiky plants so our chances of getting to the bottom without being bloodied and bruised are remote to say the least. This lethal looking bush here for instance, which I can’t quite place, looks capable of causing serious injury. I see that it’s producing tiny red fruits and as we have our botanist friend Steve Lenton with us today (although he’s opted to take a more sedate route) we’ll collect a couple and pass them on to him for identification. After all, there’s no point in having a dog and barking yourself. Talking of which, you wouldn’t just like to put your hand in and grab a couple of berries would you? Thought not. Here goes then. Ouch, first blood to the flora.

Red rocks contain iron

That’s the difficult part over, all limbs etc. intact? Good. My arm really is bleeding quite profusely now and my hand will soon be as red as that rock down there. I’d ask you to keep an eye out for some woundwort but it only grows down by the coast. The fact that both my blood and this rock are red is no coincidence. The linking factor is iron. Blood contains haemoglobin which uses iron to bind with oxygen in order to carry it from the lungs to where it is needed. Similarly, that rock down there is composed primarily of iron oxides and the chemical bonds between iron and oxygen reflect red light. This is also why arterial blood which carries blood from the lungs and has more iron/oxygen bonds is redder than venous blood which carries blood back to the lungs for oxygen replenishment and thus has fewer bonds.

Plants take up iron from the soil

Now I don’t know about you but I don’t go around eating rocks for a pastime so the question is: how does the iron get from the rock to our blood? The answer of course lies in what we eat. Plants like spinach, as we all know from Popeye, are full of iron but in fact all green plants take up iron from the earth in order to photosynthesise. Which begs the question; if it’s all to do with iron why are plants green and not red? The answer is that although the main element in chlorophyll is magnesium, iron is used in its synthesis. Without iron the plant cannot make chlorophyll and the leaves become yellowish in a condition known as iron chlorosis. So all the plants that we see around us here, from the cropped grasses to the trees, are busy taking up iron.

Herbivores take in iron from plants

The story doesn’t end there of course. All of the herbivorous animals that we eat, from this garden snail down here to that goat up there, (“Who me?” “Yes, you”) are busily devouring plant material and passing the iron along through the system. Which is good news for us because with insufficient iron in our diet we can’t produce enough haemoglobin and we become anaemic. (The word itself means lack of haem, the iron molecule in haemoglobin). The iron also gets passed along to us in the milk (the goat’s not the snail’s) and although the mineral content of goat’s milk and cow’s milk is fairly similar the body processes iron and the other minerals more efficiently from goat’s milk so it’s a useful addition to your diet.^[1]

Termites help take iron back to the soil

That just about wraps up our story of how to get blood out of a stone but having got it out, how do we put it back again? Everything that lives must die, whether it be a blood cell, a tree or one of these here termites that are aiding the process of decay. As we go through life, the trees, the termites and us, we excrete waste products and return iron to the soil along the way and then, at the end of our lives, back it all goes to be taken up again or, over geological time, to be compacted, subducted, churned about in the mantle, eventually to re-emerge on the surface as a red rock.

What goes around, comes around as they say. Talking of which, here’s Steve.

“Any idea on these berries which I’ve taken from one of these horrendously thorny bushes, at great risk to life and limb, not to mention septicaemia, for your collection?”

“I’ll have to examine the whole bush and leaves to determine the species but I'm fairly certain it’s a Rhamnus.”

Ah, that would be a Buckthorn in plain English. Not content with trying to stab me to death it’s probably injected toxic berry juice into my fingers. The things I do for botanical research. Oh well, if I’m not dead by next week we’ll continue on down and see if we can reach the village of Agios Ioannes.

The Extra Bit

And now I think we’ve earned one of those beers that I spotted in the back box of Steve’s quad bike. A lovely warm November morning for a quiet drink on a mountainside in good company and you really can’t beat the scenery.

[1] Nutra: Goat milk prevents iron deficiency study