Klingon Warship

I found this little rotifer called Keratella, looking like an armour-plated Klingon warship, or maybe a medieval chain-mail glove, in a moorland pool about 500 metres above sea level in Weardale. Under the microscope it looks like a swimming claw, propelled by those whiskery looking hairs that you can see between the armoured ‘fingers’, which also serve to produce a water current that sweeps minute food particles into its jaws. The red spot is a light-sensitive eye spot. Most amazing of all, that egg-shaped object being towed around behind one of them is an egg – but not just any old egg. These animals reproduce by cloning themselves and never reproduce sexually, so the individual inside the egg is an exact genetic copy of the adult animal it’s attached to. When I peered down the microscope, I could see this animal’s alter-ego squirming inside the egg, ready to hatch. Keratella is about a quarter of a millimetre long.

Living sponge

Bright green patches of bog moss (Sphagnum) thrive in wet hollows on the fell tops. Step into one of these and you’ll suddenly find that you’ve got a boot full of water, because this moss acts like a living sponge. Each plant constantly grows from its apex and dies from its base and the accumulated weight of living plant crushes layers of dead moss underneath, which ultimately form peat. It’s the plant’s ability to retain water, even in dry summers, that makes Sphagnum bogs such important wildlife habitats for moisture-loving wildlife. You need to look at the minute leaves under the microscope to see how they do this. Magnify the leaves a little and you can see that each leaf is a network of cells. Increase the magnification a little more and two kinds of cells are revealed – green photosynthetic ones (the living part of the leaf) and empty, transparent dead ones. The photosynthetic cells form a living network, enmeshing the dead ones. Increase the magnification further and you can see the structure of each dead cell, it’s shape maintained by beams of thick cell wall material, with a hole in each cell wall. Once these dead cells fill with water capillarity holds it firmly in place. Squeeze the moss and water flows out like water from a sponge. Tread on one of those bright green patches and the water fills your boot..........and then it's wet socks for the rest of the walk.

Water bears in space - and on my garage roof

The cushions of moss that grow on my garage roof are a rich source of microscopic wildlife, including these little tardigrades, also known as ‘water bears’ or ‘moss pigs’. These are up to a fifth of a millimetre long, with eight legs that end in claws that allow them to clamber amongst the leaves of mosses. Tardigrades feed on mosses in the same way that greenfly feed on larger plants, by spearing the plant with a hypodermic syringe-like stylet and draining out the sap - you can see the green cell contents inside the gut of one of the tardigrades in these pictures. The most amazing thing about tardigrades is that they are virtually indestructible. When their habitat begins to dry out they develop into a barrel-shaped resting cyst call a ‘tun’, and in this state can survive in a state of extreme dehydration for decades. While in the tun stage they can survive extreme environmental conditions – even extreme vacuum and cosmic radiation in space – see http://tardigradesinspace.blogspot.com/

Crustacean Castanets

Our garden pond is currently full of these little Cypris sp., a.k.a. seed shrimps, that belong to a subclass of crustaceans called ostracods. Each animal resembles a water flea enclosed within a pair of hinged shells. When they’re swimming they look like animated castanets (see video clip), when they’re at rest they look like a minute bean.

Bubbling stones

The pebbles in the pools left by the falling water level in the upper reaches of the River Wear were bubbling in the bright spring sunshine this morning. Scraping some of the thin film of slime from the stones onto a microscope slide revealed the cause – millions of minute, photosynthetic diatoms, producing oxygen bubbles. In amongst them I found several amoeba, like the one shown in the second-from-top photograph, grazing on these underwater meadows.

Lifting the edge of the blanket

I spent some time yesterday fishing the blanket weed out of my smallest pond, and took the opportunity to take a look at the microscopic organisms that live in it. There were vast numbers of ciliate protozoans, about a twentieth of a millimetres long, whizzing around at a tremendous speed. They are propelled by fringes of microscopic hairs that beat in rhythm and they can change direction instantly, so they can be tricky to photograph. The ciliate in the picture here might be a species of Oxytricha, but I’m not totally sure about that. The green objects inside it are algae that it has ingested. The two videos show a large rotifer that was attached to the blanket weed, with its ‘wheel organs’ (rings of rhythmically beating cilia) creating a vortex that sucks food into its constantly chewing jaws. These animals always remind me of twin-head electric razors. Blanket weed can be a pain in ponds, but it supports a vast array of minute organisms that are the base of a food chain for larger animals.

Sticky Jack

Came in from weeding in the garden with bits of goosegrass Galium aparine stuck to my clothes. We used to call it 'sticky Jack' when we were kids, and lobbed handfuls of the stuff at each other on the way home from school. It's the covering of tiny hooked hairs all over the plant that act like Velco, fixing it to fabrics. The hairs on the stem are shortish and curved, but those on the leaves are like fish hooks - when you look at them under the microscope.

Inside the Stomach of a Predatory Plant

The carnivorous Nepenthes pitcher plants that I grow in my conservatory are producing new leaves and pitchers, and one has caught its first fly. Deep inside the pitcher you can see the drowned insect. The dark spots on the inner wall of the pitcher are the plant’s digestive glands which secrete the enzymes that slowly dissolve their prey. The photomicrographs show the glands in the wall at x40 and x100 magnification. They not only secrete enzymes, but also absorb the products of digestion which provide the plants with essential nitrogen, for producing its own proteins. This – in effect – is the plant’s stomach.

The Inner Workings of an Onion

Onions have long been a favourite source of material for microscopists who want to explore the inner workings of a cell. Peel apart the onion bulb scales and it's easy to strip away the skin of cells that coats the scales; mount these in water on a microscope slide and large, brick-shaped translucent cells are easily visible and reveal the nucleus, that contains the DNA and controls the life of the cell. The centre of the cell is occupied by a large fluid-filled vacuole, with cytoplasm squeezed between it and the cell walls. Watch for a while and it soon becomes apparent the the cytoplasm is constantly streaming around the cell walls, carrying with it minute organelles like the mitochondria, they provide the energy that keeps the cells alive. Sometimes the cytoplasm is drawn out in strings across the vacuole, like stretched-out chewing gum. The whole of the cell is in a constant state of motion. So, next time you're about to chop an onion and chuck it in the frying pan, pause for a moment and contemplate the marvellous process shown in these video clips, which is going on in hundreds of thousands of cells in the living onion in your hand.

Rust

In Victorian times it was socially acceptable to possess books devoted to smut – provided that the smut was of the fungal variety. It’s hard to imagine that a book entitled Rust, Smut, Mildew and Mould: An Introduction to the study of Microscopic Fungi would sell well with the general public today but M.C. Cooke’s volume of the same name, published in 1870, apparently did. “In these latter days, when everyone who possesses a love for the marvellous, or desires a knowledge of some of the minute mysteries of nature, has, or ought to have, a microscope,” Cooke began confidently, “a want is occasionally felt which we have essayed to supply”. His book seems to have satisfied that want, since the preface to the second edition states that it was produced as a response to “demands from the public encouraging the publisher to proceed with a new edition”. So more smut – together with rust, mildew and mould, is what the public got. One of the plates illustrates the bright coloured patches that appear on bramble leaves, caused by the fungus Phragmidium violaceum, showing its distinctive club-shaped resting spores (teleutospores) that are released from purple pustules on the leaf undersurface (middle left illustrations). I scraped some of these onto a microscope slide and photographed them – a comparison with the plate from Cooke’s book shows that his illustration is pretty accurate. Wight Rambler has recently written about brilliantly coloured bramble leaves at http://wightrambler.blogspot.com/