Wednesday 8 February 2017

A Recipe For Life

We seem to have taken quite a detour last week to get down to this level and the waterfall should be over there somewhere. We’ll follow our ears and get there somehow but first, that looks interesting. There’s probably a correct technical term for these shallow erosions but I just call them cavelets. Let’s climb up and take a look. As you can see from the staining of the rock face, water is leaching minerals from the rocks and if you look up there you can see small stalactites forming. There are also white deposits blooming on the walls which my geologist friends tell me is probably gypsum/selenite.  They contain calcium and sulphur so, along with the limestone rocks which contain calcium and carbon, and the water, we have carbon, oxygen, and hydrogen (the basic elements of life) plus at least a couple of others to add to the recipe. We’ll push our way up through these bushes using this tumbling water course as our stairs and see what’s going on.

And up here, below the dripping stalactite, if you look carefully you can just see some threads of green algae forming. There’s a whole world of wonder in this little splash pool which began when large molecules of dissolved organic substances from the stalactite attached themselves to the wet rock. These neutralised the electrical charge of the water surface and allowed bacteria to colonise and they, in turn, secreted sticky strands that formed a nutrient trapping matrix. This matrix, known as the biofilm to periphytologists (people who study slimy rocks – yes, there really are such people), then served as a base for more bacteria to expand and diversify the biofilm and then for our green algae to grow. The algae, in its turn, will provide a home for microscopic life forms such as the ciliate we found in Life In The Olive Grove .

Algae are very basic life forms but we also have some higher forms of plant life up here. These fig branches, tenaciously clinging to the underside of this crack are just coming into bud and down in the damp crevices we have some lip ferns whilst out on the dry, stony ground, the beautiful but dangerous mandrakes are coming into flower. Their relative simplicity or complexity is reflected in their evolution: the flowering plants which include the fig and mandrake have been with us for about 120 million years, the ferns about 320 million years and the green algae maybe as long as 500 million years. Us? Well, as primates about 55 million years but as Homo sapiens only a couple of hundred thousand years.

Have you noticed these cottony threads in amongst the berries of this lentisc bush here? Alongside the evolution of plants came the evolution of insects and these threads look like the work of woolly aphids. Pass me the field microscope and I’ll see if I can find one for you. There’s one look, if you study him closely you can see him sucking up the sap from the plant. And where there are insects there are predators; there’s a minute spider that has his eye on stuffed aphid for lunch. Talking of which, let’s see if we can find some cave spiders lurking in the deeper recesses.

Do you think that you can wedge yourself up into that crack and see if there’s anyone about? Plenty of webs? That’s a good sign. You’ve found one? Good, I’ll squeeze in beside you and take a look. Hmm. It’s not a cave spider but he is rather interesting. Do you remember me telling you that you don’t have to worry about spiders in Crete because we only have one venomous one and you’re unlikely to come across it? Guess what? You’ve found one. Sorry, probably not the best time to impart that information when you’re perched precariously thirty metres up a cliff face, but don’t worry they’re pretty shy creatures and he won’t bother you unless you threaten him. All the same I think we’ll climb down. That was a Mediterranean Recluse Spider and although his bite can cause nasty skin lesions, a condition known as loxoscelism for which there’s no known treatment, it is rarely fatal. Having said that, there was a fatality last year in Italy but I believe that the unfortunate victim was already suffering from some sort of immune deficiency, which would have been a contributing factor.

Still, venomous spiders aside, a pleasant little diversion and a different angle from which to look at this wonderful thing called life. Now how are we going to get down from here?

The Extra Bit

Last week I glibly said that there is “only one authentic palm lined beach on the whole continent [of Europe]” and that was at Vai on the east coast of Crete. I am indebted to Jackie Strasis for reminding me that Phoenix theophrasti also lines Preveli Beach in southern Crete and I have also learnt that there are yet more at Ayios Nikitas in Heraklion Prefecture. Further research has turned up one other native European palm, The Mediterranean Dwarf palm, Chamaerops humilis, which lives in south west Europe. Just goes to show – you can’t believe a word that I say. Thanks for correcting me Jackie.

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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)
The Nature of Crete  (Flipboard Magazine)

Wednesday 1 February 2017

Worlds Within Worlds

Do you want the good news or the bad news? The good news is that we’ve made it safely through the Milonas Gorge. The bad news is that we have a flipping great waterfall ahead of us which means we’ll have to find a way around and down and there are no paths to follow.

No matter, the sun is shining and there’s a flying circus in the sky. In case that seems a bit odd, forget the tents, clowns and performing seals and think of the origin of the word. Circus comes from the Greek kirkos meaning a circle or ring and was applied to a place of entertainment where the seats were arranged in a circle around the performing area. It is also the generic name of the birds that circle as they hunt which we know as Harriers. There have been four species recorded on Crete: the Marsh; Hen (or Northern); Pallid; and Montagu’s. The last three are rare and the Marsh, although a frequent passage migrant in the spring, only overwinters here in small numbers. It’s a bit too high to make out details but it’s still an exciting start to the day as it’s the first Harrier of any type that I’ve seen in these parts.

This really is an impressive bit of landscape with the lower valley stretched out before us and the great towering limestone cliffs at our backs. Hard to imagine that this was once a sea bed. Look up to that patch of blue sky and try to visualise yourself looking up to the surface of the ocean instead. That it may also once have been a tropical beach is easier to imagine because the evidence is here at our feet. The thing about limestone is that it is good at preserving fossils and we’ve got a smashing fossilized palm fan here. Pity it’s too heavy to lift, it would have looked nice by my fireside at home. Palm trees aren’t entirely tropical, there is one species (Phoenix theophrastii) that is native to Europe but there is only one authentic palm lined beach on the whole continent. Where? Crete of course, at a little place called Vai on the east coast. Remind me to take you there some time.




The water here is pushing its way around the rocks, trying to get to the head of the waterfall, which means that there are some intriguing little pools around. Let’s get a sample under the field microscope and see if there’s anyone at home. That little patch of algae clinging to the rock looks promising. Ooh look, an aquatic worm. There are three types of worm that you can find in pools like these. There are nematodes which thrash about frantically (you may remember that we found some three years ago down at Ferma rock pools – see Rockin' All Over The Shore); flatworms which glide around rather gracefully; and oligochaetes like this one which are rather squirmy wormies related to the common earthworm.

We seem to be making our way steadily downwards with loads of lichens, masses of mosses and cascades of chasmophytes (rock loving plants) lining our route but I see that we also have some lovely little yellow fungi down near our feet. Do you see that milky droplet exuding from the stem?  It looks like latex (but not the same latex that you find in plants) which is exuded by members of the milk cap family. However they exude latex from outside the mushroom not from the stem and there are no milk caps with this colour and habit so it’s a waxy cap like the ones we found in the gorge last week. Just when you thought fungi couldn’t get more confusing!

Hello, we’re into the jungle. It looks as though we’ll have to crawl through this bit. Still, while we’re down here we may as well have a look about and see what’s going on. How delightful, an ants’ nest, just what we need when we’re crawling along on our stomachs. But what’s this in the nest with them? You see the little orange insect trying to hide? It’s an Ant-loving Cricket (Myrmecophilus). Ants’ nests aren’t just for ants. They are like big cities and, just as with our cities, they have a diverse wildlife all of their own. Hundreds of different species have adapted to ant city life and this is just one of them. Absolutely tiny for a cricket, they never grow wings because they never leave the city, they’re deaf and mute and have very poor eyesight. They don’t have sex either, the females have virgin births, a process known as parthenogenesis. Doesn’t sound like much of a life but they seem to get by.

The Extra Bit

At last we’ve emerged into the open and even though we’re approaching midwinter a few of the flowers are beginning to emerge. We’ve got anemones, fumana, Cretan cistus and field marigolds all beginning to open their petals in the midwinter sun. If you look over there you can see the waterfall and that’s the direction in which we’ll be heading next week.

Thanks to JJ Wuilbaut at  Mediterranean Fungi for educating me on the difference between Waxy Caps and Milk Caps and to various members of Crete Birding for chatting about the various Harriers on 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)
The Nature of Crete  (Flipboard Magazine)

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