Wednesday, 28 February 2018

The antics of sea monkeys

Human imagination is powerful and, as a result, we can readily be taken in by the power of advertising. One example of which I am especially fond is that of sea monkeys, sold through advertisements in children’s comics in the last century (see below), but still available today.

The excerpt from the advertisement shown above sums up the enjoyment that we are likely to have by watching the antics of sea monkeys and we hold the miracle of life, being able to create them by adding powder from a series of bags to an aquarium tank of water. The bags contain salts, nutrients, and the encysted eggs of brine shrimps (Artemia) that hatch to produce larvae in the saline water and these metamorphose into adults (see below) after a few days. The idea of branding the shrimps sea monkeys came from Harold von Braunhaut, a New York entrepreneur, and he encouraged us to imagine that the Artemia swimming around in tanks, some of which had lenses set into the plastic to allow a better view, had faces and were performing tricks.

I wonder how many of those who had sea monkeys (and we had some in our household when our children were young) overcame their disappointment that they were shrimps and not little monkeys, by considering the biology of these remarkable animals. The name brine shrimps gives away the habitats in which they are found – small freshwater pools with high levels of salinity, especially during drying events. Artemia can tolerate salinities from 25-250 g/L (sea water is usually 35 g/L) and they can do this because they have an impervious exoskeleton that prevents osmosis and thus water incursion at low salinities and dehydration at high salinities. That in itself is something that promotes wonder, as does their ability to reproduce parthenogenetically.

When their pools begin to dry, encysted eggs are produced and these withstand extremes of temperature, very low oxygen tension, and the presence of poisonous gases (although experiments conducted by NASA, and others, suggest they may be susceptible to the deleterious effects of cosmic rays [1,2]). They are effectively as dry as the dried pool in which they are found and are referred to as being is a state of cryptobiosis – meaning that all signs of life are hidden. They can remain in this state for years and that is why living Artemia soon appear in sea monkey tanks after we have added powder to the water. It also explains why they return after we add fresh water to a dried-out tank.

The encysted eggs of brine shrimps are not the only examples of cryptobiosis; many seeds and spores can also remain in long-term dormancy before returning to resume their “normal” life when conditions become suitable. More unusually, there are creatures that can become dried during other phases of their life cycle – tardigrades and nematode worms provide examples, as do the larvae of an African midge (Polypedilum vanderplanki) that become dried with the temporary rain pools in which they live. Animals that become cryptobiotic as larvae or adults replace water with organic compounds that maintain the integrity of tissues and, as with the production of encysted eggs by Artemia, the metabolic changes required for survival are triggered by changes in water quality that indicate that drying is about to occur.

If we are amazed by the antics of sea monkeys, how much more amazed are we that several different lineages of animals have evolved cryptobiosis and the ability to become dried? And independently, at that.

Friday, 9 February 2018

Sea Serpents

In his fascinating book [1] about the sea monsters that adorn various early maps, Chet Van Duzer writes:

I would suggest that sea monsters on maps have two main roles. First, they may serve as graphic records of literature about sea monsters, indications of possible dangers to sailors – and datapoints in the geography of the marvellous. Second, they may function as decorative elements which enliven the image of the world, suggesting in a general way that the sea can be dangerous, but more emphatically indicating and drawing attention to the vitality of the oceans and the variety of creatures in the world, and to the cartographers artistic talents.. ..During the Renaissance, sea monsters on maps reflect and express an increased general interest in wonders and marvels.. ..the more exotic the creature depicted, the better, and the study of both maps and images of exotic creatures was thought to sharpen the intellect and be educational. Maps decorated with sea monsters, by implication, would offer the viewer an even richer intellectual experience.

If that is the case, the map produced by Olaus Magnus (1490-1557), and shown below, must have been of great significance. Of the many sea monsters depicted, perhaps the most well-known is the sea serpent described by Olaus as follows [1]:

Those who do their work aboard ship off the shores of Norway, either in trading or fishing, give unanimous testimony to something utterly astounding: a serpent of gigantic bulk, at least two hundred feet long, and twenty feet thick, frequents the cliffs and hollows of the sea coast near Bergen. It leaves its caves in order to devour calves, sheep, and pigs, though only during the bright summer nights, or swims through the sea to batten on octopus, lobsters, and other crustaceans. It has hairs eighteen inches long hanging from its neck, sharp, black scales, and flaming red eyes. It assaults ships, rearing itself on high like a pillar, seizes men and devours them.

Such a creature (the red “snake” attacking a ship in the image below) would deter fisherman, and other sailors, from entering Scandinavian waters and, as Van Duzer points out, this may be one of the reasons for the location of sea serpents, and other monsters, on maps.

Sea serpent myths have a wide distribution and examples have been described by Aristotle, Pliny the Elder and many others [2]. Although there were sightings of serpents from Norwegian waters in the Nineteenth Century, the most well-known observation of one of the creatures was made by Captain Peter M’Quhæ of H.M.S.Daedalus off the south-west coast of Africa. As an Officer in the Royal Navy he was viewed as a reliable source and The Times of 9th October 1848 carried a report of M’Quhæ’s sighting. His letter to The Admiralty was quoted by Philip Henry Gosse in The Romance of Natural History [3] and it contains the following description of the creature: was discovered to be an enormous serpent, with head and shoulders kept about four feet constantly above the surface of the sea, and, as nearly as we could approximate by comparing it with the length of what our maintopsail-yard would shew in the water, there was at the very least sixty feet of the animal [at the surface of the water], no portion of which was, to our perception, used in propelling it through the water, either by vertical or horizontal undulation..

..The diameter of the serpent was about fifteen or sixteen inches behind the head, which was, without any doubt, that of a snake; and it was never, during the twenty minutes that it continued in sight of our glasses, once below the surface of the water; its colour a dark brown, with yellowish white about the throat. It had no fins, but something like the mane of a horse, or rather a bunch of sea-weed, washed about its back..

There are differences to the sea serpent described by Olaus Magnus but, as with all descriptions of these creatures, it is large and snake-like. Gosse, who was a literalist Christian and believer in Creation, had sufficient faith in M’Quhæ’s sighting to propose that the sea serpent was an enaliosaur; spending many pages of The Romance of Natural History sifting through the conclusions of others. 

What did M’Quhæ, and others aboard his ship, see? Given that humpback whales using bubble nets could be the origin of belief in the kraken [4], the answer may lie with the behaviours of contemporary marine animals, although there is no obvious explanation for the appearance of the sea serpent. There are many who still wish to believe in the survival of dinosaurs, and the well-established mythological importance of snakes and dragons with extraordinary powers certainly influences our imagination.

[1] Chet Van Duzer (2013) Sea Monsters on Medieval and Renaissance Maps. London, The British Library.

[2] Joseph Nigg (2013) Sea Monsters: The Lore and Legacy of Olaus Magnus’s Marine Map. Lewes, Ivy Press.

[3] Philip Henry Gosse (1860) The Romance of Natural History. London, J. Nisbet and Co.

The copy of Olaus Magnus's map used in the illustrations above come from Nigg's book (see reference [2]).

Friday, 2 February 2018

Charles Kingsley and Henry Gosse go dredging in Torbay

During the Nineteenth Century explosion of interest in the Natural History of shores, there was also much to discover about animal life in shallow coastal waters and this tempted naturalists like Edward Forbes to use dredges to bring animals to the surface, where they could be examined more closely.

In his biography of his father, Edmund Gosse describes a dredging trip that Philip Henry Gosse made with his good friend Charles Kingsley in Torbay. Although Kingsley is best known as the author of The Water Babies, Hereward the Wake and Westward Ho!, like many other Victorians he had a passion for Natural History and wrote Glaucus to summarise his knowledge and to inspire others [1]. The book contains many glowing references to Henry Gosse, and Kingsley was clearly a great admirer. This is what Edmund wrote [2]:

Charles Kingsley was several times our companion. The naturalists would hire a small trawler, and work up and down, generally in the southern part of the bay, just outside a line drawn north and south, between Hope’s Nose and Berry Head. I think that Kingsley was a good sailor; my father was a very indifferent one, and so was I; but when the trawl came up, and the multitudinous population of the bottom of the bay was tossed in confusion before our eyes, we forgot our qualms in our excitement. I still see the hawk’s eyes of Kingsley peering into the trawl on one side, my father’s wide face and long set mouth bent upon the other. I well recollect the occasion (my father’s diary gives me the date, August 11, 1858) when, in about 20 fathoms outside Berry Head, we hauled up the first specimen ever observed of that exquisite creature, the diadem anemone, Bunodes coronata; its orange-scarlet body clasping the whorls of a living Turritella shell, while it held in the air its purple parapet crowned with snow-white spiky tentacles.

Was this the specimen that Henry used in making the illustration for his important work Actinologia Britannica (shown below)? This is how Henry describes his discovery of these sea anemones (since re-named Hormathia coronata [3]) [4]:

This fine species first occurred to myself when dredging off Berry Head [seen in the far distance in the photograph below], in about 20 fathoms, in August 1858. Three or four specimens came up in about the same number of hauls. In every case the animal was adherent to the shell of the living Turritella terebra, a mollusk which is so abundant there that the dredge comes up half filled with it. The base of the Bunodes clasps the long turreted shell, nearly enveloping it when adult, only the apex and the mouth of the shell being exposed.

It is not unusual for sea anemones of some species to associate with the shells of living snails and the relationship appears to be mutualistic – the anemone being moved around and the mollusc gaining protection. No doubt, Charles and Henry were thrilled not only with the capture of Bunodes, but with the abundance of Turritella.

Perhaps you don’t have the same level of enthusiasm for sea anemones and snails, but can appreciate the enthusiasm of others at a time when there were many discoveries to be made? Although not a good sailor, Henry made trips by boat because he was very curious about all marine creatures not just those of the shore, which was his usual haunt and where he collected many specimens to be returned to his aquarium tanks in Sandhurst, his home in St Marychurch, Torquay. Edmund describes his appearance when out collecting [2] and I used this quote in an earlier blog post, in which I contrasted the decorum, and modesty of dress, required by women collectors [5]:

Even as a little child I was conscious that my father’s appearance on these excursions was eccentric. He had a penchant for an enormous felt hat, which had once been black, but was now grey and rusty with age and salt. For some reason or other, he seldom could be persuaded to wear clothes of such a light colour and material as other sportsmen affect. Black broadcloth, reduced to an extreme seediness, and cut in ancient forms, was the favourite attire for the shore, and after being soaked many times, and dried in the sun on his somewhat portly person, it grew to look as if it might have been bequeathed to him by some ancient missionary long marooned, with no other garments, upon a coral island. His ample boots, reaching to mid-thigh, completed his professional garb, and when he was seen, in full sunlight, skimming the rising tide upon the sands, he might have been easily mistaken for a superannuated working shrimper.

What a lovely description – and how nice to have it to complement the image of formal photographs (see below, for example). I can easily visualise Henry busying himself around the coast, completely absorbed in his work and caring little about appearances. Maybe that’s why he is a hero of mine, just as he was for Charles Kingsley?

[2] Edmund Gosse (1896) The Naturalist of the Sea-shore: The Life of Philip Henry Gosse. London, William Heinemann.

[4] Philip Henry Gosse (1860) Actinologia Britannica: A history of the British sea-anemones and madrepores. London, John Van Voorst.

Friday, 19 January 2018

Amelia Griffiths, Mary Wyatt and a curious phenomenon in Torbay

Mary Wyatt was a dealer in shells and minerals from her shop in Torquay [1]. During the boom in exploring seashores that occurred during the early Nineteenth Century, such shops supplied visitors with important specimens to add to their cabinets of curiosities. Mary Wyatt’s shop was as well known in Torquay as Mary Anning’s shop in Lyme Regis, where fossils could be obtained, as well as other mementoes; the passion for Natural History including rocks and minerals as well as living organisms.

In addition to running, and supplying, her shop, Mary Wyatt collected algae that were dried and pressed, with some of her collections made up into volumes published as Algae Danmonienses - illustration by dried specimens resulted necessarily in a very limited number of copies being produced [2]. None of this would have been possible without the close co-operation of another famous resident of Torquay, Amelia Griffiths (1768-1858) [3], the subject of an essay by Philip Strange and a biographical note by Ann Shteir. From their articles [4,5], we learn that Amelia Griffiths was born Amelia Warren Rogers on 14th January 1768 and married a vicar, William Griffiths, in 1794. He died in 1802 and she then raised her five children on her own, eventually settling in Torquay in 1829, where Mary Wyatt was one of her servants. By this time, Amelia was already well known for her knowledge of algae, their locations and their biology, and she corresponded with many of the leading authorities of the day.

Philip Strange concludes his article [4] by writing:

The more I investigated the story of Amelia Griffiths, the more I found similarities with Mary Anning. Both were systematic collectors, acquiring immense expertise in their fields and passing on samples to male scientists who furthered their own careers as a result. Both were strong women who pursued their interests whether or not these conformed to norms of society. Griffiths is known to have collected at Lyme Regis so perhaps she encountered Anning on the beach; it is an interesting thought. Anning is now better known, partly because her discoveries were much more significant for science and partly because of the well developed Mary Anning-industry in her home town.

Algae Danmonienses, with its limited number of copies was unlikely to spread the fame of Amelia and Mary and, while Amelia corresponded with many botanists, she produced few articles – Shteir [5] mentioning only two notes to The Phytologist and a list of Natural History specimens in Blewitt’s The Panorama of Torquay [6].

She was certainly well-known and respected in Torbay and Blewitt wrote:

The article on Natural History will be acceptable to all, containing, as it does, the most recent of Mrs. Griffiths’s truly beautiful discoveries in the difficult department of marine botany..

Blewitt also describes an interesting phenomenon at Elberry Cove in Torbay in which Amelia’s expertise was called upon [6]:

At a short distance from the beach, the surface of the water presents a curious phenomenon. A fresh-water spring, rising of course in some part of the chain of hills above the cove, makes its exit from the sandy bottom, about eight or ten feet below the surface of the sea at low water mark.. ..It ascends perpendicularly with considerable force and forms a smooth circle, four or five feet in diameter, on the surface of the sea. Two of these circles are occasionally seen, in consequence, perhaps, of the accumulation of sand; and their size, depth, and distance from each other vary at different times, according as they are influenced by the swell or weather. They are of course best seen at low tide and when the sea is smooth. In April of the present year, we made some experiments in conjunction with Mrs Griffiths, in order to ascertain the character of the water ejected by this spring. The result was satisfactory, and proved that it was a body of fresh water pouring out of an aperture of large size, and with such strength that the sand disturbed was forced by its power to the surface. The appearances within the circle resembled the effect of oil poured on the water.. ..[and] The volume of fresh water must be considerable as the salt taste of the sea perceptibly diminishes in the neighbourhood of the spring. This phenomenon will be visited by the natural philosopher with much pleasure..

Quite what experiments were carried out by Amelia Griffiths are not known – apart from tasting the sea water!

Having been brought up In Torbay, I made many visits to Elberry Cove (shown above at a time of far from ideal conditions) but never recall seeing the upwelling from springs that is described by Blewitt. Perhaps they no longer exist?

[1] M. Rendel (1994) Women in Torquay in the First Half of the Nineteenth Century. The Transactions of the Devonshire Association 126: 17-39

[5] Ann Shteir (2004) Griffiths [née Rogers], Amelia Warren (1768-1858). Oxford Dictionary of National Biography

[6] Octavian Blewitt (1832) The Panorama Of Torquay, A Descriptive And Historical Sketch Of The District Comprised Between The Dart And Teign. London, Simpkin and Marshall + Torquay, Cockrem