The Magic of Mushrooms

These are the radiating gills of the toadstool known as weeping widow Lacrymaria velutina. For more about this toadstool, visit http://cabinetofcuriosities-greenfingers.blogspot.com/2009/10/weeping-widow.html

The surface layer of the gills, known as the hymenium, produces thousands of spores, and for these to be successfully released into the airstream the gills must always be vertically aligned, so they are very sensitive to the force of gravity and quickly realign themselves if the stipe of the toadstool bends away from the vertical and tilts the cap.

Here, at a microscope magnification of x40 you can see the spores lining the surface of the gills....

...and here, at a magnification of x100 you can see that each is shaped like a small brownish-black lemon..

The spores are formed in groups of 4 on a cell called a basidium, attached to it by short stalks, seen here at a magnification of x400 under the microscope....

... and these appear to be two basidia where the spores are beginning to form. When they're mature and drop off they'll fall vertically down the gaps between those parallel, perfectly vertical gills and will be wafted away in the airstream

If you cut off a toadstool cap, turn it gill side down on a piece of paper of contrasting colour to the spores and leave it in a warm room where there are no draughts for a couple of hours, the falling spores will produce a beautiful spore print.....

...like this

Golden Algae

Forty years ago, when I was a university student, life – more specifically, cataloguing life – was relatively simple. Living organisms fell into one of five kingdoms: bacteria, plants, animals, fungi ................and protists, which were a rag-bag of mostly small organisms that no one knew enough about to be able to fit them into any of the other four categories. The science of classifying living organisms and understanding their evolutionary relationships has moved on, thanks to our ability to look at species’ relationships by comparing their DNA sequences.......which has made classifying life more intriguing and much more complicated. Those rag-bag protists are now subdivided by biologists into several kingdoms, one sub-division of which contains this lovely little organism, less than a millimetre long and called Dinobryon, which is known as a golden alga (or Chrysophyte). There are now thought to be about a thousand different Chrysophyte species, mostly single-celled, but this is one of the more complex types. They all have a golden yellow pigment called xanthophyll, which you can just about detect in the top photo of Dinobryon. This organism, which is common around pond and lake edges, consists of individual cells, each with a couple of lashing flagellae (which you can just about make out poking out of the uppermost 'vase' in the bottom photo), with each cell encased in a glassy vase and attached to a branching stem. The top photo is taken with polarised light, which generates the lurid interference colours, while the bottom one is taken with interference contrast microscopy, which gives better resolution of the individual cells in their ‘vases’.

Last of the Summer Whines

Ever had the experience where you get into bed, turn the light out, lay awake for a few minutes then pick up a high-pitched whining in the room – which can only be a mosquito? There’s no alternative but to get up and catch it, because there’s no possibility of going back to sleep in the knowledge that you might become a victim of one of these dipteran Draculas. So having caught it, I thought I’d have a quick look at it under the microscope – and it turned out to be an object of great beauty (double-click images for a better view).

The first thing that strikes you about a mosquito under the microscope is its wonderful eyes, sparkling with a kaleidoscope of iridescent colours, that provide wrap-around vision that’s even more complete than in dragonflies (seen above from above and below from below).

Then there are the antennae. This is a female (and therefore a blood-feeder – the males feed on plant juices), identifiable by those radio aerial-like antennae, which are bushier in males. Mosquitoes find their prey by vision, heat sensing, carbon dioxide sensing and scent, so if you are alive and breathing they’ll find you, even with the light out.

Then, of course, there’s that stiletto-like proboscis........

Seen here (above) in victim’s-eye view

With the lights going on earlier every night, more mosquitoes find their way into houses at this time of year – until the first frosts kill them off. I guess it’s one of the perils of having a garden pond that they can breed in, although water in a forgotten bucket in the corner of a yard will suit them just as well.

I’m not certain of the identify of this species but I think it’s Culex pipiens which according to Keith Snow’s Mosquitoes (Richmond Publishing Naturalists’ Handbooks No. 14) ‘feeds almost exclusively on birds’. So, maybe if I sleep with the budgie in the bedroom I’ll be OK..... although he adds, reassuringly, that adults hatching at this time of year feed exclusively on plant juices and enter buildings only to hibernate. That’s alright then. The budgie can relax.

Travelling light

This strange object, magnified one hundred times under the microscope, is a single seed of a common spotted orchid Dactylorhiza fuchsii. The lower photo shows a couple of the orchid’s seed capsules, with the dust-like seed laying on the paper below.

Unlike seeds of oak and horse chestnut, which send their seeds out into the world with a large food store surrounding the embryo, orchids have a much more minimalist approach to equipping their embryos for future survival. The orchid embryo – inside the darker object in the centre of the seed in the top photo – has no food store and is housed in a fragile papery coat, just one cell thick. The whole seed is no larger than a speck of dust and is so light that it can be swept up by air currents and wafted long distances – orchid seed could easily be blown across the English Channel, for example. So, unlike heavy seeds with a large food that are unlikey to disperse very far from the parent plant, orchid seeds are great travellers heading for random destinations and this accounts for their tendency to suddenly appear in unlikely places – lawns, roadside verges, industrial spoil tips, to name but a few. A large orchid flower spike will produce tens of thousands of these minute seeds, but only a tiny fraction will ever achieve the next critical step in the life cycle – landing on soil that contains the essential mycorrhizal fungus that will link up with the germinating seed and provide the embryo with the nutrients that it lacks until the seedling is large enough to produce leaves and survive on its own. After that the orchid's roots returns the favour by supplying its partner fungus with nutrients for the rest of the orchid's life. Early growth of the orchid seedling is slow and its leaves passes unnoticed - until it's large enough to produce a spectacular flower spike........and to read about the next step in the life cycle - pollination of the flowers - take a look at  http://cabinetofcuriosities-greenfingers.blogspot.com/search/label/orchids

The Most Numerous Multicellular Animals on Earth

Looking like a writhing python – but less than a millimetre long – this nematode worm came from water that I squeezed out of a patch of wet moss. It was photographed using polarised light, which generates the interference colours you can see here; the bottom image is nearer to the true appearance – most small nematodes are transparent.

Nematodes – commonly known as roundworms – are ubiquitous and there are thought to be about half a million species, which may well be a conservative estimate. Some live freely in the soil or in fresh or salt water, some are predators, many are parasites of animals and plants and several species cause serious damage to the roots of crop plants.

One microscopically-small species, called Phasmarhabditis hermaphrodita is a parasite of slugs and is commercially available in garden centres for killing these garden pests. Another species, a parasite of sperm whales, grows to a length of 9 metres. A square metre of fertile soil will contain several million nematodes. A single rotting apple was once found to contain 90,000 individuals.

One nematode species, called Caenorhabditis elegans, is used by biologists for investigating the way in which a complex animal develops from a single fertilised egg. Its transparency allows biologists to follow and map the fate of every cell in its body during its development. Amazingly, consignments of this species that were part of an experiment in space were recovered alive in the wreckage of the space shuttle Columbia, which disintegrated during re-entry into Earth’s atmosphere in 2003 (see http://news.bbc.co.uk/1/hi/sci/tech/2992123.stm)

Nudibranch Video

Here's a short video of Eubranchus, the nudibranch featured in the Seaweed Microcosm post, below. Note the tiny swimming crustacean that puts in a brief appearance, about 9 seconds in from the start.

For more on British species of nudibranch, visit http://www.seaslug.org.uk/nudibranchs/
where you can read all about them and access pictures of all the British species

For pictures of their exotic, gaudy tropical cousins, see
http://ngm.nationalgeographic.com/2008/06/nudibranchs/doubilet-photography

A Seaweed Microcosm....

If you want to explore exotic marine life in shallow seas you could jet off to a warm climate and scuba dive over a coral reef.......or you could just nip along to your nearest stretch of coastline (in our case Whitburn, near the mouth of the River Wear at Sunderland), collect a few small pieces of red seaweed and some seawater, take it home and examine it under the microscope.

This (below) is the piece of seaweed in question, floating in a rockpool.......

....and these (below) are just a few of the animals that I found living in it...

..First to break cover were these little crustaceans called isopods (which literally means 'equal legs' - all their legs are the same length - woodlice are terrestrial isopods). These are highly active little detritus feeders, breathing through gills at their tail end, and belong to a genus called Idotea..

..and they were swiftly followed by this little amphipod (meaning legs of two distinct lengths, long ones at the front, shorter at the back) which emerged from the waving weed fronds. Note the exquisite eyes of these little shrimp-like animals, known as gammarids...(more of those eyes in a future blog).....Whereas isopods tend to be flattened dorsiventrally (i.e. top-to-bottom), amphipods tend to be flatted laterally (side-to-side).

It soon became apparent that the thicker parts of the seaweed were covered with colonies of another phylum of animals called bryozoans (literally 'moss-animals'). These live colonially, interconnected, in little calcareous compartments. In the case of this species, each individual's shell was performated with holes, like an exquisite microscopic ceramic vase. The magnification used here is roughly x50Bryozoans (I haven't identified this species for certain yet, but I think it's Electra pilosa) feed by waving a tentacled arm called a lophophore, that looks a little like an old-fashioned wire egg whisk.

You can see extended lophophores (rather indistinctly, I'm afraid) in the following couple of photos.......

 ....The third phylum of animal to put in an appearance under the microscope (so far we've had crustaceans and bryozoans) was this exquite little sea slug, known as a nudibranch, which belongs to a genus called Eubranchus. Fully extended, this was about 3mm. long - a juvenile, that will probably grow to five or six times this size. Nudibranches are carnivores and it may well have been feeding on the lophophores of some of those bryozoans, although they typically feed on hydroid colonies (more about them in a future post). The back of this nudibranch is covered with strange, skittle shaped objects that wobble from side-to-side as it glides through the water. They're called cerata and are for gas exchange (nudibranch means 'naked gills' and that, in effect, is what these are). Remarkably, some species of nudibranch that feed on hydroids that are armed with stinging nematocysts (for more on nematocysts, see http://cabinetofcuriosities-greenfingers.blogspot.com/2009/09/flower-animal.html) can incorporate the nematocysts of their prey into the body wall of their own cerata, to protect themselves. Nudibranches detect their prey using incredibly sensitive organs called rhinophores, which are the top pair of tentacles at the head end. The pictures below are all of the same animal, but the lighting varies.

So there you have it.........a whole community of weird and wonderful microscopic animals living in a single frond of red seaweed in a rockpool. I spent a couple of very enjoyable hours photographing these but I've not doubt that I could have spent another day, extracting more microscopic marine life, before I exhausted the possibilities of this microcosm. There's a short video of the nudibranch on a separate post, above this one.You can find out more about all of these animals at http://www.marlin.ac.uk/species.php

Fatal Attraction

As the nights draw in and the lights go on earlier each evening, increasing numbers of insects are drawn to the light at windows. The local spider population seems to be aware of this, judging by the network of webs spun across our windows each morning, often capturing this little fly, known as an owl midge.

Owl midges, sometimes called moth flies, are only about 3-4mm. long so don’t make much of a meal for a spider. Their single pair of broad ‘delta’ wings, reminiscent of those of a moth and fringed with hairs, are a distinctive feature, but they seem to spend as much time running around on vegetation as in flying.

These flies, whose larvae feed on decaying vegetation in damp places, have a distinctive hump-backed profile and are covered in rosettes of hairs, especially on the thorax which, when viewed from above, is supposed to have a fanciful resemblance to an owl’s face, between partially outstretched wings.

You can find these little flies all-year-round but in spring they seem to be attracted to wild arum Arum maculatum flowers (below)

Open up the chamber at the base of the Arum inflorescence where the flies are imprisoned by this plant and you’ll often find owl midges inside.

Scarlet wild arum fruits (below), which are a conspicuous feature of hedgerows and woodland edges at this time of year, are often the work of this minute pollinator.

Mussels.....Alive, Alive O!

Mussels Mytilis edulis spend their infancy in the plankton, as swimming veliger larvae (see http://oceanexplorer.noaa.gov/explorations/02mexico/background/mussels/media/bivalve_veliger.html), but then they settle on a substrate and begin a more sedentary life. This (above, x40) is a minute juvenile mussel that anchored itself to a green seaweed frond in a rockpool on a Northumberland beach (Warkworth).


In this slightly older example the tiny shell it developed as a planktonic larva is at its base (pale brown) and since it settled it has produced the vestiges of its future shell, but it has yet to develop much pigmentation, so at this stage the shell is still transparent, creating some interesting possibilities for examining its internal structure under the microscope.... and here (above, x100) you can just make out the comb-like gills inside the pair of shells - they are the row of downward-pointing teeth running along the length of the shell, from bottom left to top right. Take a look at the two videos at the bottom of this post and you'll see how these gills work - they're lined with tiny beating hairs (cilia) that create a powerful current of water over the gills, that extract oxygen and also capture tiny food particles that are wafted into the animal's digestive tract. Somehow (and no one yet knows how) the animal can separate organic food particles from indigestible inorganic grit and debris that is expelled. Even a tiny mussel like this can process a large volume of seawater, thanks to these frantically beating rows of cilia on the gills, here shown in the videos at the bottom of this post at magnifications of x100 and x200.

This still image (above) shows a mussel at a slightly later stage (about 3mm. long), when the shell valves have become pigmented and have lost their transparency. Between the gaping shell valves you can just make out the inhalent and exhalent ports where water is wafted in and squirted out by the ciliary current.

In this side view of the same juvenile mussel (above), the original transparent shell valves of the infant mussel are visible, attached to the pigmented shell that has subsequently developed. They mark the point where the two shell vales are hinged together.

Mussels often settle at very high densities - like these, several months older than the microscopic examples depicted above, packed shoulder-to-shoulder on a rocky outcrop on the shore at Warkworth in Northumberland. Mussels attach themselves to their substrate with a protein glue that sets underwater, to form extremely strong byssus threats that prevent the animal being dislodged, even when pounded by breaking waves in the full fury of a storm. There is a lot of scientific research going on into this protein, for potential medical use – as a glue for repairing broken human bones or in dentistry (see http://www.asknature.org/strategy/4f16bf8321224ea8b146277ccdace9690). For more on the marine biology of mussels, see http://www.marlin.ac.uk/speciesfullreview.php?speciesID=3848

Sea Gooseberry videos

Prey's-eye view of a sea gooseberry. Unlike sea anemones and jellyfish, which have stinging tentacles, those of sea gooseberries are sticky

Higher magnification movie of the propulsion system - hairs (cilia) that are fused into eight rows of saw-tooth combs. Each row can be stopped and started independently, giving very precise directional control. The beating combs create flickering interference colours.

Side view of a sea gooseberry swimming

The long, trailing tentacles dangle below the animal. Swimming into a swarm of sea gooseberries, some of which are large enough to catch small fish, would be a fatal mistake for any small planktonic animal.

These are some videos of the sea gooseberries that I caught yesterday and posted at http://beyondthehumaneye.blogspot.com/2009/09/sea-gooseberries.html

and

http://cabinetofcuriosities-greenfingers.blogspot.com/

You can read more about these remarkable animals at http://www.ucmp.berkeley.edu/cnidaria/ctenophora.html

and

http://faculty.washington.edu/cemills/Ctenophores.html