Category Archives: Science

Books Environmental politics History Science

Notes from Rain: Four Walks in English Weather by Melissa Harrison

p. 32 “One reaons we know how much rain has fallen where, and when is the British Rainfall Organisation: A quintessentially eccentric body and one of the first examples of what we now call ‘citizen science’. George James Symons, who began his working life in the Meteorological Department of the Board of Trade, set up the Association in the middle of the 19th century in response to public concern that rainfall was decreasing across the British Isles. He recruited a small network of initial observers, then wrote to The Times in 1853 listing the further locations he wanted, calling for observers ‘of both sexes and all ages’ and offering to subsidise the cost of instruments. By 1867 he had 1,300 observers, nad had to leave his post at the Board of Trade; by his death in 1900 there were 3,408, drawn from ‘nearly every social grade from peer to peasant’… In 1916 the BRO was called upon to determine whether the use of artillery on the Western Front was somehow responsible for one of the wettest winters on record… the opinion given … was that there was no connection. The following winter would prove less wet, despite the artillery barrage of the Somme, but bitterly cold .. continued to publish its records until 1991.”

p. 55 “The aptly named George Merryweather displayed his storm forecaster, the ‘Tempest Prognosticator’ at the Great Exhibition of 1851. Looking not unlike a miniature merry-go-round, it consisted of a circle of 12 pint bottles, each containing a little rainwater and a single leech. His idea was that, on sensing electrical activity in the atmosphere, the leeches would crawl to the top of the bottles, triggering whalebone levers connected to a bell on the topmost dome; the more times the bell rang, the greater the likelihood of an approaching storm. … believed that it could easily be connected to the telegraph network in a way that the bell in St Paul’s, London, could be rung to signal an approaching storm. But then, he also believed that arranging the bottles in a circle would allow the leeches to see one another and not become lonely.”

p. 62 “Because they need their food to be over 50% water, rabbits like to feed at dawn and dusk when the dew is down.”

p. 75 Dartmoor “became a vital source of sphagnum moss during the First World War when it was gathered in great quantities, dried and sent off to be used as wound dressings due to its abosrbency and healing properties; its been shown to slow the growth of fungi and bacteria. Twelves species are found on Dartmoor, and all can hold eight times their own weight in rain.”

p. 82 “A recent study by the Environment and Sustainability Institute, University of Exeter, showed that one square metre of inrtensively improved grassland held just 47 litres of grassland compared to the 269 litres per square metre held by unimproved ‘rhos’ pasture with its naturally occurring purple moor grass and sharp.flowered rush.”

Books Environmental politics Science

Notes from The Soil, By N.K. Davis, N. Walker, D.F. Ball and A.H. Fitter

p. 49 A mycorrhiza is a root infested with a particular type of generally beneficially fungus … The most widespread and ancient type, although not the most familiar, bears the cumbersome name of vesicular-arbuscular mycorrhiza (VAM)… form no visible external structures, so it is impossible to tell if a plant has the association without microscopic examination of stained roots. VAM are formed by a small group of fungi… can only survive in association with the roots of a plant. Their principal distinction is the size of their spores, which are quite enormous by fungal standards – in one species of Gigaspora they are over half a millimetre across, compared to a typical figure for most fungi of around 1/100th of a mm. … most plants that can form VAM do so nuder natural conditions because the fungus appears to offer a solution to an otherwise sever problem – the acquisition of the essential nutrient phosphorus… occurs in soil as phosphate ions which are so sparingly soluble that they move only very slowly through the soil… normally less than a millimetre through soil in a day … Remarkably, fossils of one of the first land plants Rhynia, about 400 million years old, have fungi associated with their rhizomes that appear almost identical to modern VAM fundgi.

p. 51 The best-known nonVAM mycorrhiza “is the ectomycorrhizal or sheathing mycorrhiza, characteristic of many forest trees, especially the Pinacae (pines, spruces, larchs firs), the Betlaceae (birches, alders) and the Fagacae (oaks, beeches).. almost all are toadstools, members of the Basidiomycetes. Some are well known and distinctive, such as fly agaric which forms a mycorrhiza with birch…. Ectomycorrhizal roots are stubby and often fork dichotomously, giving dense clusters. Each root tip is surrounded by a sheath of tightly woven fungal hyphae and other hyphae radiate away from this int the soil… The fine fungal threads penetrate the soil, picking up the immobile phosphate ions and transporting them back to the sheath. Meanwhile the fungal hyphae beneath the sheath, which are in contact with the root cells, obtain sugar from them to feed the fungal tissues.”

p. 52 It does seem that extomycorrhizal trees are better able to colonize poor soils than VAM trees, and this is probably because the former get more benefit from the more active fungi. Of course there is a cost to this: the ectomycorrhizal tree probably has to give up more of the carbon that it fixes than does the VAM tree so the latter may be at an advantage on better soils.
Another remarkable feature of mycorrhizas that has recently come to light is their ability to link plants together. .. BY labelling trees with radioactive isotopes, it has been found that materials can pass from plant to plant by means of these links… there is intriguing evidence that seedlings establish in swards more readily if they become mycorrhizal than if they remain uninfected… If this turns out to be widespread and important phenomenon t may force us to rethink our view of plant communities: ecologists have in the past tended to view them as dominated by intense competition between plants; it may be there is more cooperation than we thought.”

p. 57 Soil fauna – flatworms, rotifers or wheel animalcules, hairy backs, land nemerteans, eelworms, earthworms, bear animalcules (Tardigrada), woodlice, terrestrial sand-hopppers, mites, spiders, millipedes, centipedes.

pp. 158 Like an unpredictable genie, pesticides have proved to be a somewhat mixed blessing, for their overall effects can seldom be fully predicted. There are few if any pesticides that are completely specific to their target organisms: discrimination between harmful and harmless organisms is rarely adequate.

Books Environmental politics History Science

Notes from The Running Hare: The Secret of Farmland by John Lewis-Stempel

p. 25 All farms used to have an untidy corner where machinery went to die, and where thistles and nettles grew. Intensive farming has all but done away with these little no-man’s-land nature reserves; modern farms are as obsessively tidy as showroom Hygena kitchens.”

p. 26 “The Romans, who may well have introduced the hare to Britain, were keen hare-eaters. … Pliny the Elder advocated a diet of hare as a means of increasing sexual attractiveness…. Pliny’s ther proposition concerning hares was almost entirely contradictory: he declared the animals were hermaphrodites – a belief which eventually got worked into Christianity. Hares are a recurrent motif in British church architecture, standing for reproduction without loss of virginity .. p105 As with many animals sacred to older religions, medieval Christians changed the hair into an animal f ill-omen, saying witches shape-shifted into hare form to suck cows dry. Sailors considered hares so unlucky they could not be mentioned at sea. And not just sailors; country folk refused to call the hare by its name. p. 227 Hares have large hearts to enable them to achieve such speed. Up to 1.8% of body weight, compared to 0.3% for a rabbit.”

p. 56 “how ploughmen used to tell whether the earth was warm enough to sow (they’d drop their trousers and sit on the ground: if the bare bottom could bare the earth it was warm enough.”

p. 84 To walk behind a horse and harrow is to bring one into accord with all the ages. .. In harrowing half an acre Willow [Shetland pony] and I walk five miles. No one except kings and clergy was fat in the time of the horse… I am happy harrowing, an emotional state which may, according to scientists at the University of Bristol, be enhanced by soil itself. A specific soil bacterium, Mycobacteriyum vaccae, activates a set of serotonin-releasing neurons in the dorsal raphe nucles of the brain, the same ones targeted by Prozac. You can get an effective dose of Mycobacterim by walking in the wild, or gardening. “
p. 126 “The first wildflowers in my personal ploughland … are scarlet pimpernel, and common field speedwell, both delicate bejewelled creepers over ground, one red, the other blue. Their seed has been harboured safe in the earth for years: common field speedwell can germinate after 20 years. … as common on roadside verges as it is in arable fields, and travellers in years gone by sewed the flower into the lining of their coats as a charm.”

p. 137 Corn marigold is as old as British agriculture itself, since it was probably brought here by the Neolithic people. Arable farmers, however, have never warmed to its sunny splendour, since the fleshy leaves impeded the harvest reaping. Henry II issued an ordinance against “a certain plant called Gold”, requiring tenants t uproot it, which was probably the earliest enactment demanding the destruction of a weed. In A Boke of Husbandry, 1523, John Fitzherbert included ‘Gouldes’ in his blacklist of plants that ‘doe muche harme’.”
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Books Environmental politics Science

Looking back four billion years, with a very foggy picture…

(A shorter version was first published on Blogcritics)

The early evolution of life on Earth is a subject I’ve always found fascinating, but it’s a couple of decades since I last revisited the subject in any depth, and having read Oxygen: A Four Billion Year History by Donald E Canfield I now know that pretty well everything I’ve ever read or been taught on the subject was wrong. The idea that gradually algae spread around the earth, pumping out oxygen in a steady-growing stream, well it simply isn’t true.

It’s not surprising my teachers were so wrong, for as I read in Oxygen, a big breakthrough in understanding early life on Earth came in only 1999, when a colleague and friend of the author, James Farquahar, found some highly unexpected results on a study of sulfur isotopes, in Archaen rocks aged from 2.3-2.4 billion years ago. That led to the conclusion that at this time there’d been interaction between UV light and sulfur dioxide gas from volcanoes. Today, that’s absorbed by ozone, of course from oxygen. Further studies on the form some molybdenum takes in rocks of this age from some parts of the world, however, show that in some places there was free oxygen – what’s come to be known as a “whiff” of oxygen.

What was happening was that by around 2.5 billion years ago, the production of oxygen by photosynthesis more or less balanced the consumption of it by volcanic gases. Sometimes the balance shifted one way, so the oxygen disappeared, sometimes the cyanobacteria were beating the volcanoes.

It was between 2.3 and 2.4 billion years ago that “the great oxidation event” (GOE) changed that. Quite what caused it is still up for grabs. Canfield has a favourite, not evolution of cyanobacteria but a less active mantle, as it gradually cooled, cutting the production of reducing gases. Seems entirely plausible to this interested amateur.

But the GOE wasn’t entirely even – it was Canfield suggests concentrated in the atmosphere, the oceans remaining anoxic and rich in sulfide, with more sulfur being weathered from the land through oxidative weathering of sulfides. This is now known as the “Canfield Ocean” – yes after the author, we’re in seriously expert hands here.

Related to that is the likelihood that for much of the Earth’s “middle ages” atmospheric oxygen levels were much lower than today’s. (Any time machine travellers would need to take oxygen cylinders.) The author’s theory is just 10% of today’s levels, others suggest 40-50%.
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Books Environmental politics Science

How does a hedgehog give birth?

Originally published on Blogcritics

How does a hedgehog give birth, given that the babies are born already with spines? The kind of question that mightn’t regularly pop into your head, but certain one that sticks there when you think about it.

The answer is that the babies are born swollen with fluid, so the prickles are beneath the surface of the skin. After birth, the fluid is absorbed and the prickles (which are evolutionarily speaking modified hair) emerge.

That’s one of the many fascinating facts that I learnt from A Prickly Affair: My Life with Hedgehogs by Hugh Warwick, a man who clearly doesn’t only live and breathe hedgehogs, but has certainly spent a lot of wet, cold English nights tracking them around the countryside.

I learnt that their ancestor is thought to have emerged in Asia during the Eocene, although there are ancestors dating back 70 million years, into the dinosaur age. In Britain we have Erinaceus europaeus, the western European hedgehog, although there’s species distributed throughout Eurasia, and down through North Africa.

They’re closely related to shrews and voles, being predominately insectivorous (Hugh watches one consume a large juice slug, having first wiped much of its slime off on a handy road surface – although it still chews a strong tasting leaf afterwards, presumably to cleanse its palate), unlike the American porcupine, which is a rodent. (And of course the Australian echidna, which is a marsupial.)

But this book is far from a collection of facts about hedgehogs. What it is mostly is a exploration of the author’s relationship with hedgehogs, and his meetings with some of the many people obsessed with them. (No wonder they’ve just been voted Britain’s national animal.)

We watch Hugh’s relationship with them and love of them develop as he takes on jobs tracking individuals around the countryside – primarily on projects to see how rescued ones fare when released back into the wild. Against all the rules, he develops, entirely understandably, a personal relationship with his subjects, giving them names and admiring their individual characters. (Although I suspect he’s wrong when he says voles and shrews aren’t similarly complex – look at them in the same detail I think you’d find the same complexity.)

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Books Science

Pterosaurs – forget practically everything you were ever told

tail

A shorter version was first published on Blogcritics

I last really looked at Pterosaurs some 30 years ago, when as a fossil-obsessed young teen, I haunted the paleontology section of the Australian Museum in Sydney. After reading Mark P. Witton’s new Pterosaurs: Natural History, Evolution, Anatomy I now know that practically everything the displays told me about pterosaurs, that they were incredibly light, fragile, clumsy creatures, walking on two legs, primitive in their evolutionary conception, were, while the “wisdom” of the time, entirely wrong.

Pterosaurs is an unusual format – a coffee table-style book in its format, yet seriously academic, uncompromisingly serious in its content, except for an occasional whimsical light note, most commonly in the captions. To the right is, in Witton’s terms, is “one of the coolest-looking pterosaurs known”, Caviramus filisurensis. He also notes that “diddly-squat has been said in print about the biomechanics and functional biology of boreopterids“.

It’s unusual, but it works. I doubt too many non-academic readers will absorb every word about the anatomical morphology of ptesoaur types, or the long-running and often unresolved academic debates about the relative evolutionary relationships between different groups, but all the detail is there if you should want to dive in

giraffe

For those looking for the lighter version, there’s wonderful illustrations, also by Witton, of both reconstructions of pterosaurs in their environment, so far as we can know it, as well as a couple that help to put them in context, as with azhdarchid transposed with a human and a Masai giraffe right.

And the middle ground, in which I belong as a reader, to a whole exploration of the evolution, physique, physiology and ecology of this diverse, long-lived family that finally disappeared with the dinosaurs.

A lot of conventional wisdom is dispelled. Among the biggest surprises, that on the ground they were effective, often fast, movers, fully quadrupedal, that their bodies were primarily covered with a pelt of what are called pycnofibres, not scales or feathers, and that they aren’t dinosaurs, but belong to their own branch of the evolutionary tree, although whether that branches off before the Crurotarsi or after the Scleromochlus, or off earlier branches, is clearly a subject of much debate.

More, they were much heavier than had been predicted in studies of most of the last century, and not gliders or clumsy fliers, but every but as effective as the birds who eventually replaced in them in the skies. And they probably didn’t evolve from gliders, but from small, high energy little creatures (there’s a strong argument for the pterosaurs being warm-blooded – helping explain the pelt), running around trees or craggy cliffs.  Further, the headcrests that are a prominent feature of some species are not, at least generally, either aerodynamic features, or temperature regulators, but competitive mating features, generally only found on the males, which suggests, with other evidence, that many were lek breeders, with males competing for the control of harems of females.

So there goes pretty well everything you thought you knew about pterosaurs, if you picked the knowledge up a couple of decades ago. That’s not surprising, for Witton begins with short survey of pterosaurology, which records that, for reasons not really explicable, from the 1930s to the 1970s, studies virtually stopped, so that he world’s first popular pterosaur books, Dragons of the Air, published in 1901,  remained effectively the current state of knowledge.
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