Return to the Serra da Estrela

towards_manteigas

Back in October I wrote about the algae and other plants that I had found in a small stream draining the Serra da Estrela mountains in Portugal (see “Notes from the Serra da Estrela”).  I’ve now had a chance to look more closely at the diatoms that I found there, and can offer a few thoughts on the ecology of the stream.

I collected two samples from the stream: one by brushing the top surface of the granite stones with a toothbrush and the other from the darker patches that I described in the earlier post.   These were a mix of algae and mosses, with the former dominated by cyanobacterial filaments and diatoms.   I merged the two samples prior to digesting them, but the biofilm on the submerged rocks was very thin so it is the diatoms from the dark patches that dominate the slide that I prepared from this stream.   As my preliminary observations suggested, motile diatoms were very abundant in this sample, with Surirella roba, Navicula angustaand N. exilis all common, along with some Pinnularia and Nitzschia.   I do not often find motile diatoms to be quite so abundant in fast-flowing upland streams, but I suspect that this is because I look in the wrong places.   Our standard sampling method involves scrubbing the tops of submerged stones which, in this type of stream at least, are not situations where motile diatoms thrive.  By contrast, the tangle of cyanobacterial filaments and dead organic matter creates a very different environment, where an ability to adjust position in order to move away from densely-shaded areas and, perhaps, from situations where bacteria and fungi had used up all the available oxygen, was an advantage.

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Surirella robafrom the stream at Unhais de Serra, September 2018; a. – f.: valve views; g. – i.: girdle views. Scale bar: 10 micrometres (= 1/100thof a millimetre). The photo at the top of the post shows the view along the valley of the Rio Zêzere towards Mantiegas in the Serra da Estrela.

misc_diatoms_unhais_sep18

Miscellaneous diatoms from the stream at Unhais de Serra, September 2018: a. – d.: Cocconeis placentula, complete frustule, rapheless valve and two raphe valves; e. – g.: Navicula exilis; h. N. angusta; i. – k.: Pinnularia subcapitata, two valve views and a girdle view.  Scale bar: 10 micrometres (= 1/100thof a millimetre). 

A chain-forming species of Fragilariawas abundant in the original sample although, by the time I had prepared a slide, the chain had disintegrated into individuals or pairs of cells.  These all belonged to a member of the Fragilaria capucinacomplex, though I am not sure which one. There were also a few cells of the free-living (i.e. non-chain-forming) Fragilaria gracilis.    Eunotia minoror a close relative was also present, sometimes also forming short chains and, finally, I found a number of cells of Cocconeis placentula(possibly var. klinoraphis).

These are all diatoms that I would expect to find in a stream draining a hard rock such as granite in an area that is remote from any industrial or mining influences that might lead to artificial acidification.   There are mines in the area, but these are further south.  These do have a measurable effect on the biology of local streams, as the references at the end of this post attest.   However, this particular stream appears to be in rude health.

A curious side-effect of the years that I have spent looking at diatoms is that a sample such as this can evoke the environments from which it came: an assemblage of soft-water circumneutral diatoms conjures, in my mind, a particular landscape.   The label on the slide, of course, takes me straight back to our time in the Serra da Estrela but, in a more general sense, the diatoms capture an essence that transcends any one particular time or place.   Analysing diatom slides can become an escape from the humdrum and a chance to remember warmer days …

fragilaria_unhais_sep18

Fragilaria species from the stream at Unhais de Serra, September 2018: a. – g.: chain-forming member of Fragilaria capucina complex (a.-c.: valve views; d.-g.: girdle views); h.-j.Fragilaria gracilis.  Scale bar: 10 micrometres (= 1/100th of a millimetre).

eunotia_cf_minor_unhais_sep18

Eunotiacf. minorfrom the stream at Unhais de Serra, September 2018: j. – n.: valve views; o. valve view of a related species; p. girdle views. Scale bar: 10 micrometres (= 1/100thof a millimetre). 

References

Luis, A.T., Teixeira, P., Almeida, S.F.P., Matos, J.X. & Silva, E.F. (2004).  Environmental impact of mining activities in the Lousal area (Portugal): Chemical and diatom characterization of metal-contaminated stream sediments and surface water of Corona stream.  Science of the Total Environment409: 4312-4325.

Silva E.F., Almeida, S.F.P., Nunes, M.L. & Fredrik, A.T.L. (2009). Heavy metal pollution downstream the abandoned Coval da Mó mine (Portugal) and associated effects on epilithic diatom communities.  Science of the Total Environment407: 5620-5636.

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Unorthodox icons …

Towards the end of my most recent trip to Bucharest I came across, almost by chance, the Art Collections Museum, located on Calea Victoriei about 10 minute walk north from the National Museum of Art.  It brings together a number of collections that have been acquired by the state over the years, keeping each intact so that they reflect the taste of the original owners rather than reassembling them into broader thematic groupings.  On the day of my visit it was almost deserted, with attendants outnumbering visitors, despite this being the first Wednesday of the month, meaning that admission was free.   Their eyes followed me as I browsed, and their footsteps tracked mine through the empty rooms.

A museum such as this inevitably has some parts that enthral whilst other parts that fail to enthuse me. Highlights for me were the expressionist art of Alexandru Phoebus and the odalisques of Iosef Iser, both artists I had not previously encountered who had brought emerging ideas back from Paris and Berlin.   Then I walked into a room with a wall closely-hung with some very striking icons.  Two aspects struck me: their luminosity and the almost cartoon-nature of the scenes.  Imagine what Roy Lichtenstein might have produced were he to have brought his Pop Art sensibilities to religious subject matter.   The luminosity, I discovered, was because they had been painted on glass – a practice that arrived in the largely Catholic area of Transylvania from Hungary in the late 18thcentury.  This period coincided with the destruction of Orthodox monasteries and, with this, the loss of traditional icon painting skills.   Glass painting was, initially, a secular art form but, over time, it became a medium for religious imagery, initially drawing on Catholic representations of religious themes but gradually returning to Orthodox themes.

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Three glass icons from the Art Collections Museum in Bucharest.

The Catholic influence is apparent in the narrative content of some of the images that I’ve included here (see the Lamentation over the Dead Christ on the right-hand side of the top row and the centre of the bottom row, and the Last Supper on the left-hand side of the bottom row). Compare these with more traditional icons (see, for example, “The art of icons …”).   The middle image on the upper row is the Mystical Winepress, drawing on the metaphor of Christ as the true vine (Isaiah 27:2-5, John 15:1).  At the bottom right there is a rather strange-looking image of a figure with three faces but just four eyes).  This is a depiction of the Holy Trinity: God being simultaneously three persons and one.  It is also the image, of those I have chosen to depict, closest in style to traditional Orthodox icons.

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More icons on glass from the Art Collections Museum in Bucharest.

It is hard for a modern viewer, steeped in the visual culture of the 20thand 21stcenturies, to appreciate the impact of these images.  These were produced at a time when painters in western Europe were preoccupied with realism and capturing the dynamism of the world around them.   These are pared-back, almost cartoon-like depictions.  On the one hand, they are folk art, produced by artists without formal training; yet, at the same time, they are depicting such familiar subjects (for the audiences) that a suggestion of the subject matter is all that is needed.  Icons on the wall of a gallery are divorced from their context and analysing them in terms of visual representation does not do them justice. Icons in a church or in the home of an Orthodox believer are catalysts to deep spiritual experiences and can achieve this without sophisticated painting techniques.   Jesus, in Matthew’s Gospel, says we have to “become like children” (18:3) and, remembering how cartoons were able to draw me into imaginative worlds when I was young, perhaps it should not be a surprise that such apparently simple images make effective icons.

 

Algae from the Alto Duoro …

From the highlands of Serra da Estrela w headed north-west towards the vineyards of the Duoro Valley from which the grapes that make port are picked.  I’m supposed to be on holiday but, as the narrow road twists and turns down a steep hillside, with vineyards on both sides, I see a case study in how humans alter rivers and their catchments to suit their needs.  I wonder if the passengers on the cruise ships that move sedately through this beautiful landscape have any idea of just how difficult this same journey would have been just fifty years ago.   Now there are 51 large dams within the watershed, regulating the flow and, at the same time, generating much-needed hydroelectricity.   Before these were in place, the only way to get the port from the quintas in the Alto Duoro to Porto was to load the barrels onto a “barco rabelo”, and then to plot a perilous path through the rapids before using a combination of sail, oars and oxen to make the slow journey back upstream (you can see videos of these journeys on YouTube).

A replica of a barco rabelo moored in the Rio Duoro at Porto, September 2018.

The Rio Douro is a type of river that is rare in the UK but very common throughout the rest of Europe in that it crosses (and, for part of its course, forms) national boundaries.  There are a few rivers in Ireland which straddle borders (the Foyle is one, and some of the headwaters of the Shannon can be found in County Fermanagh) but, mostly, this is a complication that our river managers do not have to face.  By contrast, eighty per cent of the Rio Douro’s catchment lies in Spain (where it is called the Duero) and it is actually the largest watershed on the Iberian Peninsula.   The whole European project, and its environmental policy in particular, makes so much more sense when you are looking at a well-travelled river.

Our immediate objective was the Quinta do Bomfin at Pinhão, which produces grapes for Cockburns’, Dow’s and Taylor’s ports.  However, after a morning walking through the vineyards and following a tour of the winery (the robot that has replaced human grape treaders has, we learned, been carefully calibrated to match the pressure that a human foot exerts, lest the grape seeds are crushed, imparting bitterness to the resulting wine) plus some port tasting, the lure of the river was too strong.

A view across the Douro Valley from Quinta do Bomfin at Pinhão.   This, and the previous two photographs, were taken by Heather Kelly.

The river bank at Pinhão is lined with rip rap (loose stones) enclosed in mesh cages to protect it from erosion from the waves created by the many cruise ships that make their way up the river with tourists.   This, along with the floating jetties at which they embark and disembark, meant that it was not easy to get access to the river; however, I eventually found a small slipway close to the point where a small tributary joins.  There were a few loose stones with a green film in shallow water that I could just reach, plus some algal mats coating the concrete of the slipway at water level.   I managed to get small samples of each to bring back for closer examination, attracting the usual curious stares from passers-by in the process.

The mats on the slipway were composed of an alga (technically, a cyanobacterium) that has featured in this blog on several occasions in the past: Phormidium autumnale (see “In which the spirit of Jeremy Clarkson is evoked”).   This is the time of year when the Douro is at its lowest so living at this point on the slipway means that it spends a small part of the year exposed to the air, but most of it submerged.

Phormidium cf autumnale on a slipway beside the Rio Douro at Pinhão, September 2018.  The left hand image shows the mats on the lower part of the slipway; the right hand image shows individual filaments.  Scale bar: 20 micrometres (= 1/50th of a millimetre).

The stones beside the slipway had a thick greenish film which, when I looked at it under a microscope, turned out to consist largely of bundles of thin cyanobacterial filaments belonging to a relative of Phormidium: Homoeothrix janthina (kindly identified for me by Brian Whitton).   Homoeothrix differs from Phormidium in that the filament are often slightly tapered, rather than straight-sided and usually aggregated into colonies, often growing vertically towards the light rather than intertwined to form mats.   It is a genus that I see in the UK (including, sometimes, in the River Wear) but which I have not previously written about on this blog.   The photos below show tufts of filaments but it would be quite easy to imagine several of these clumps joined together to form a hemispherical colony, before I disrupted them with my vigorous sampling technique.

Left: the rip rap at the edge of the Douro at Pinhão from which I sampled algae in September 2018; right: the stone after vigorous brushing with a toothbrush.

Bundles of filaments of Homoethrix janthina from the River Douro at Pinhão. Scale bar: 20 micrometres (= 1/50th of a millimetre).

Many of my posts try to make the link between the algae that I find in lakes and rivers and physical and human factors in those water bodies and their surroundings.  That is not an easy task in a large river basin such as that of the Douro as there is so much more of a hinterland including large towns in Spain such as Valladolid.   The river, to some extent, integrates all of these influences and, whereas the vines around Pinhão have their roots in nutrient-poor granite and schist soils, the river’s journey to this point has covered a range of different rock types, including chalky clay soils in the Spanish part of the catchment and the water reflect this.   This cocktail of physical alteration and pollution, shaken up with a dash of international relations, recurs in the largest rivers throughout Europe and is either a fascinating challenge for an ecologist or a complete pain in the backside, depending on your point of view.

I’ll come back to the Douro in a few weeks, once I’ve had a chance to have a closer look at the diatoms.  Meanwhile, I have one more stop on my travels along the Rio Douro, at the port lodges of Vila Nova de Gaia to try some vintage port …

Reference

Bordalo, A.A., Teixeira, R. & Wiebe, W.J. (2006).  A water quality index applied to an international shared river basin: the case of the Douro River.  Environmental Management 38: 910-920.

The end of the journey: port maturing in barrels at Cockburn’s lodge in Vila Nova de Gaia.

 

Notes from the Serra de Estrela

At the end of my last post I suggested that the next time I wrote it may be from Portugal.   In reality, tiredness and, to be frank, a steady consumption of Vino Verde intervened and this post may be about Portugal but is not, alas, written from that country.   Our travels took us from Lisbon northwards to Covilhã, a town on the edge of the Serra da Estrela mountain range, then onwards to the Duoro valley and Porto, and finally back to Lisbon.   The lower part of the Duoro is the home to many of the Vino Verde vineyards, although our focus was mostly on the vineyards further upstream from which the grapes for port are grown.  I’ll write more about the Duoro in a later post but, first, I want to take you on a journey to the Serra da Estrela.

These are the highest mountains in mainland Portugal (there is a higher point in the Azores) with a summit at 1993 metres at Torre.  Unusually, for the highest peak in a mountain range, there is a road all the way to the top, along with a couple of shops and a small bar/restaurant.   On the day we visited, a couple of hardy cyclists had toiled their way up from the plains but most of the visitors had driven up.   We had stopped on our route up from Covilhã to explore the granite landscape and botanise so felt that we had earned our bica and Pastéis de Nata by the time we got to the very top.

Much as I appreciate a summit that satisfies a caffeine addiction, the real interest lies elsewhere, with the road up from Covilhã passing through some dramatically-eroded granite outcrops, composed of huge boulders apparently perched precariously on top of each other.  These resemble the granite “tors” we find in Dartmoor in south-west England, and have a similar origin.   The area around the tors had distinctive vegetation that will, no doubt, be described in greater length in a post on Heather’s blog before too long.   The free-draining sandy soils that the granite landscape creates mean that there was not a lot of surface water for me to indulge my own passions, so I will have to take you to another part of the Serra da Estrela for the remainder of this post.

Granite landscapes near Torre in the Serra da Estrela Natural Park in northern Portugal, September 2018.  

We found an inviting stream as we were walking near Unhais de Serra, at the southern end of the Natural Park.  The first plants to catch our eye were a submerged Ranunculus species with finely-divided leaves and five-petelled white flowers sitting at the water surface.   As well as these, we could see shoots of patches of water dropwort (Oenanthe sp.) and, looking more closely, several of these appeared to be growing out of dark coloured patches which turned out to be a submerged moss overgrown with algae (more about which a little later).   I am guessing that, once the rains come, much of these mini-ecosystems will be washed downstream leaving just a few moss stems to be colonised again next year.

Submerged vegetation in the stream at Unhais de Serra in September 2018 (40°15’44” N 7°37’21” W).  The top photograph shows a Ranunculus species and the lower photograph shows mosses overgrown with algae (a mixture of Cyanobacterial filaments, diatoms and coccoid green algae), within which young plants of Oenanthe sp. have taken root (top photograph: Heather Kelly).

Somewhat to my surprise there were also some patches of Lemanea.   This is a red algal genus that I usually associate with late winter and spring in my own part of the world, so I had not expected to find such prolific growths at this time of year at lower latitudes.   Maybe Iberian species of Lemanea behave differently to those with which I am familiar?

The Lemanea species found in the stream at Unhais de Serra in September 2018.  The top photograph shows it growing in situ and the lower photograph is a close-up.  The filaments are about a millimetre wide.

The dark film itself contained a variety of algae, some of which I have put in a plate below.   There were some cyanobacterial filaments which looked like Oscillatoria to me but which were not moving (their life between collection and examination was less than ideal).  There were also a large number of diatoms, mostly Navicula and Surirella.  Again, both would have been moving around in a healthy sample but were static when I got around to examining them; the chloroplasts in the Surirella, in particular, were not in very good condition).  I also saw some chains of Fragilaria species and several small green algae (especially Monoraphidium, discussed in the previous post).  I’ll return to the diatoms in a future post, once I have been able to get permanent slides prepared and examined but first impression is that I am looking at a community from a low nutrient, circumneutral environment.

Some of the algae living in the dark films overgrowing mosses in the stream at Unhais de Serra in September 2018.   a. – c.: Navicula angusta; d. –g. Surirella cf. roba; h. – i. two different chain-forming Fragilaria sp.; j. – k.: Navicula cf cryptocephala; l. – m.: Oscillatoria sp.    Scale bar: 20 micrometres (= 1/50th of a millimetre). 

The diatoms, in particular, reiterate the important point that notwithstanding the huge number of new species that have been described in recent years, it is possible to peer through a microscope at a sample from anywhere in Europe and see a familiar set of outlines that, for the most part, give a consistent interpretation of environmental conditions wherever you are (see, for example, “Lago di Maggiore under the microscope”).   That same rationale applies, to some extent to other organism groups too: we have recently shown this for macrophytes in shallow lakes for example.   Likewise, the geology here was shaped by the same broad forces that created the landscape of south-west England even if local climate means that the flora surrounding the tors in the Serra da Estrela is adapted to more arid conditions than that on Dartmoor.    It is important that, when we travel, we see the differences but, perhaps even more important in this fractured age, that we see the similarities too.

References

Chapuis, I.S., Sánchez-Castillo, P.M. & Aboal Sanchero, M. (2014).  Checklist of freshwater red algae in the Iberian Penisula and the Balearic Islands.   Nova Hedwigia 98: 213-232.

Poikane, S., Portielje, R., Deny, L., Elferts, D., Kelly, M., Kolada, A., Mäemets, H., Phillips, G., Søndergaard, M., Willby, N. & van den Berg, M. (2018).   Macrophyte assessment in European lakes: Diverse approaches but convergent views of ‘good’ ecological status.  Ecological Indicators 94: 185-197.

Return to Cyprus …

A few weeks ago I described some of the algae that I found during a visit to the Avgás Gorge (pictured above) in Cyprus, including a chain-forming Ulnaria (see “Cypriot delights …”).   I’ve now had a chance to prepare cleaned valves from this material so we can take a closer look.

The chain-forming habit had already led David Williams to suggest Ulnaria ungeriana (Grunow) Compère 2001 and more detailed observations have confirmed this.  This is a species that was actually first described from Cyprus (actually Northern Cyprus) and it was also recorded quite extensively during a survey of the island’s diatoms a few years ago.   Unfortunately, some of the key diagnostic characters – such as small marginal spines and striae composed of single rows of pores – cannot be seen with light microscopy but the former, at least, can be inferred from the chain-forming habit.   Note, too, how the long chains that dominated the population in the live state, fell apart when the sample was cleaned with oxidising agents and I did not see more than three cells joined together in the new preparation.

Ulnaria ungeriana from Avgás Gorge, Cyprus, April 2018.   Scale bar: 10 micrometres (= 1/100th of a millimetre).

The Ulnaria ungeriana cells are mostly about 100 – 150 mm long and 7-8 mm wide, with a striae density of 9-10 / 10 mm.   They have parallel sides, narrowing to rostrate to slightly sub-capitate ends, and central areas that reach to the valve margin and which are slightly longer than they are broad.   Unfortunately, most of these characteristics overlap with those of Ulnaria ulna in all but most recent identification guides.   This species was first described by Nitzsch in 1817; it would have been one of the more conspicuous diatoms visible with the relatively basic equipment available at the time, with a magnification of about 150x.  His drawings are of live cells, mostly in girdle view, which means that many of the details which modern diatomists use to discriminate species are not apparent.   Moreover, the material on which these drawings are based is no longer available so we cannot go back to this in order to ascertain the characteristics of the original Ulnaria ulna and, to increase the confusion yet further, it is possible that Nitzsch has illustrated more than one species (see the reference by Lange-Bertalot and Ulrich below).

It would be, in short, very easy to look at a population of Ulnaria ungeriana in the cleaned state and match it to the descriptions of Ulnaria ulna which, under various names, have appeared in the identification literature over the past 100 years or so.   You might just detect the small marginal spines if you have a good microscope and know what you are looking for.  In the live state, however, the ribbon-like colonies are a very distinctive feature yet these do not survive preparation, putting anyone who only encounters this species on a permanent slide at a distinct disadvantage.   It is a good example of how examination of live material can add valuable information to an understanding of a diatom species yet, inevitably, many diatomists make little time for examination of their samples before dropping them into their bubbling cauldrons of oxidising agents.

High magnification views of the ends and central portions of Ulnaria ungeriana valves.   Scale bar: 10 micrometres (= 1/100th of a millimetre). 

What do we know about the ecology of Ulnaria ungeriana?   Our survey of Cypriot streams a few years ago yielded 11 records, forming up to four percent of all diatoms in the sample.  This means it is both less widespread and less dominant in samples than some other Ulnaria species.   It was often found along with other Ulnaria species, in particular U. mondii and, though generally not associated with reference sites (one out of the 11 records), it was mostly found in relatively clean conditions.   It was also associated with sites with high conductivity, which corresponds with the limestone geology that we saw in the Avgás Gorge.   On the whole, these environmental preferences are similar to those of other Ulnaria species from Cyprus that we’ve studied (see reference in earlier post).

The last question is perhaps the hardest to answer.  What benefit does the chain-forming habit confer upon Ulnaria ungeriana?   Ulnaria often forms tufts of upright cells sharing a common pad of mucilage at the base, and it is often (but not exclusively) found as an epiphyte on other plants.   We can’t rule out the possibility that the Ulnaria ungeriana chains are not also attached at one end, but it is also possible that the chain-forming habit means that they are easily entangled with the Chara and filamentous green algae that I described in the earlier post.   Both mucilage pads and entangled chains fulfil the same role of keeping the alga in the same spot in the stream, particularly where there are other plants and filamentous algae to offer extra protection from the current.

There is some speculation in the final couple of sentences but that’s never a bad thing for an ecologist.  If nothing else, it provides me with a reason to return one day …

Ecological preferences of Ulnaria ungeriana at running water sites in Cyprus.  a. pH; b. conductivity; c. total nitrogen (TN) and d. total phosphorus (TP).  Arrows indicate the mean value for each variable, weighted by the relative abundance of Ulnaria ungeriana in the sample.

Reference

Krammer, K. & Lange-Bertalot, H. (1991).   Süsswasserflora von Mitteleuropa 2 Bacillariophyceae, 3 teil: Centrales, Fragilariaceae, Eunotiaceae.   Spektrum Akademischer Verlag, Heidelberg, Berlin.

Lange-Bertalot, H. & Ulrich, S. (2014).  Contributions to the taxonomy of needle-shaped Fragilaria and Ulnaria species.   Lauterbornia 78: 1-73.

Cypriot delights …

I could not return from my visit to Cyprus without an algal sample and a fine opportunity presented itself early last week when we visited the Avgás Gorge, on the Akámas peninsula at the west coast of Cyprus, just north of Pathos.  This is a spectacular limestone ravine whose steep sides offered welcome relief from the Mediterranean sun.  At points, as in the photograph above, the ravine narrowed to just a few metres wide, reminiscent of the siq which guards the entrance to Petra except that instead of exquisite carvings we stumbled across a Russian team conducting a glamour shoot.

A small stream made its way down the gorge.  The presence of woody debris at intervals suggested a considerable head of water during the winter months but, at this time of year the water has reduced in power, tumbling across a series of boulders into stagnant pools, interspersed with short runs shaded either by the high cliffs or the vegetation that flourished away from the harsh glare of the sun.

In the sections where water was still running there were clumps of Chara tangled up with filamentous algae, with plenty of bubbles of oxygen as evidence that both were busily photosynthesising away.  The filamentous algae was a coarse unbranched filament that was clearly a relative of Cladophora but which did not match any of the genera or species that I had encountered before (see “Fieldwork at Flatford” for similar situation).   There were pebbles and cobbles between these clumps, their surfaces criss-crossed by the galleries of caseless caddis larvae – probably Psychomyiidae, according to Richard Chadd.

Chara growing in the stream at Avgás Gorge in western Cyprus, April 2018.

Cladophora or a relative growing in the stream at Avgás Gorge in western Cyprus, April 2018.  The scale bar is 50 micrometres (= 1/20th of a millimetre). 

There were a number of diatoms present too, the most abundant of which was a chain-forming Ulnaria.  Unfortunately, despite having just co-authored a paper on Ulnaria from Cyprus, I cannot name the species, as I saw no cells in valve view.  I will have to return to this subject once I have prepared a permanent slide from the sample that I brought back.   The chloroplasts in the illustration below are not in a very healthy state because the sample lived in a fridge for almost a week before I was able to get it under a microscope.  Had I looked at this sample 20 years ago, I would have assumed that I was looking at a species of Fragilaria, as most keys then stated categorically that Synedra (the former generic name) were solitary rather than chain-forming.  However, we now know that there are several Ulnaria species that form chains although most that I see in my regular haunts in the UK do not.   Our paper states that the species we describe form short chains although, as we worked from cleaned samples collected by other people, I now wonder if that was an artefact of the preparation process and whether these, too, formed longer chains in their living state.

A chain of Ulnaria from the stream at Avgás Gorge in western Cyprus, April 2018.  Scale bar: 20 micrometres (= 1/50th of a millimetre).

Though it is rare for me to stray into describing the invertebrate life of streams, the Psychomyiidae are actually an important part of the story here, as the larvae graze algae from the surface of the stones.  They create a silk tube and this, in turn, becomes covered with fine sediment to create the galleries that are visible in the picture.   We know that invertebrates can change the composition of the attached algae by grazing but I sometimes wonder if the caseless caddis larvae also change the composition by creating myriad patches of very fine sediment across the rock surface.   If you look closely you can also see a couple of Simuliidae (blackfly) larvae.  These attach themselves to the rock by a circle of hooks at their last abdominal segment (I think that is “bum” in entomological language) and then use fan-like structures around their mouths to filter tiny particles from the water.  However, I have also seen Simuliidae larvae bent double on rock surfaces in order to hoover up particulate matter and algae that live there.

That, I thought, was just about enough natural history for one day.   I put my toothbrush and bottle back into my rucksack and made my way back down until, turning the corner, I stumbled across the Russian glamour models.   I’ve often written about the similarities between freshwater ecosystems in different parts of Europe but you don’t often see a bikini – or less – in April in my cold, damp corner.

Galleries of Psychomyiidae larvae on the top of a limestone cobble from the stream at Avgás Gorge in western Cyprus, April 2018.

Reference

Cantonati, M., Lange-Bertalot, H., Kelly, M.G. & Angeli, N. (2018).  Taxonomic and ecological characterization of two Ulnaria species (Bacillariophyta) from streams in Cyprus.   Phytotaxa 346: 78-92.

Wallace, I. (2003).   The Beginner’s Guide to Caddis (order Trichoptera).  Bulletin of the Amateur Entomologists’ Society 62: 15-26.

Letter from Cyprus

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Travel can be one of the most rewarding forms of introspection ….
Laurence Durrell, Bitter Lemons, 1957

When I stepped off flight EZY1973 from Manchester to Paphos on Saturday night I passed a personal milestone. Arriving in Cyprus means that I have now visited all 28 Member States of the European Union. Starting with (West) Germany in 1972 on an exchange visit before the UK was even a member of the European Economic Community, followed shortly after by a family holiday to southern Austria (where my father had been stationed just after the war) with a day trip to Slovenia (then part of Yugoslavia), the number started to increase in the late 1990s when I became involved in the work of CEN, the European Standards Agency and, from the mid-2000s onwards, with the intercalibration exercise associated with the Water Framework Directive. A few years ago I made a list and realised just how many I had visited, after which, I have to admit, my choice of conference and holiday destinations was driven by this rather childish whim. Latvia, Malta and Bulgaria, all subjects of posts on this blog, were ticked off, leaving just Cyprus. This year, a family holiday to celebrate my mother’s 80th birthday provided the opportunity and, after some shameless lobbying, we had booked a villa near Paphos via AirBnB and were on our way.

How Europe has changed in the 47 years since my first overseas trip. Twelve countries were behind the Iron Curtain, three of the remainder were right-wing dictatorships. Two have merged (East and West Germany) whilst seven have become disentangled from previous relationships (the Baltic States from the USSR, Slovenia and Croatia from the former Yugoslavia and the two former constituents of Czechoslovakia from each other). Cyprus, from where I am writing, was in political chaos in the early 1970s. A former British colony whose territory was argued over by Greece and Turkey, it was soon to be split into two, separated by a buffer zone. I used to browse my Collins World Atlas assuming national borders to be fixed and immutable; the older and wiser me wonders where (and when) the next changes will come from.

The intercalibration exercise, in particular, was an opportunity for an exchange of ideas and I counted co-authors from 23 of the 28 EU states on my publication list. Looking back, these papers show remarkable consistency in some aspects of ecology across Europe whilst, in other respects, I am much more cautious about assuming that knowledge gained in my damp corner of north-west Europe can be applied to warmer and more continental regions. This publication list includes, incidentally, two papers about Cyprus, despite never having either visited before or having a native Cypriot on my list of co-authors. In the first paper, we worked with an Austrian employed by the Ministry of the Environment but, for the second, the samples were collected and analysed by Italians and Germans whilst I helped out with data analysis. Scientific colonialism is not, perhaps, dead?

My favourite? I don’t think I should single one of the 28 out. The food and culture of the warm lands of the Mediterranean basin draw me but I think that the parched summer landscapes would lose their appeal if I was there for too long. I find the grey, damp climate of my own corner of Europe wearisome but the greenness of the Spring and Summer, and the Autumn colours almost compensate. My ideal, in other words, seems like it should be a semi-nomadic existence but that, too, would pale with time. The truth is that, for me, elsewhere, being wanted, is always more wondered at ….

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