The challenging ecology of a freshwater diatom?

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Amphora pediculus from Polly Brook, Devon, December 2016. Scale bar: 10 micrometres (= 1/100th of a millimetre).

The images above show one of the commonest diatoms that I find in UK waters.  It is a tiny organism, often less than 1/100th of a millimetre long, which means that it tests the limits of the camera on my microscope.  In recent months, however, it is not just the details on Amphora pediculus’ cell wall that I am struggling to resolve: I also find myself wondering how well we really understand its ecology.

The received wisdom is that Amphora pediculus favours hard water, does not like organic pollution and is relatively tolerant of elevated concentrations of inorganic nutrients.  This made it a very useful indicator species in a period of my career when we were using diatoms to identify sewage work s where investment in nutrient-removal technology might yield ecological benefits.  There were many nutrient-rich rivers, particularly in the lowlands, where any sample scraped from the upper surface of a stone was dominated by these tiny orange-segment-shaped diatom valves.   Unfortunately, twenty years on, many of those same rivers have much lower concentrations of nutrients (see “The state of things, part 2”) but still have plenty of Amphora pediculus.   Did I get the ecology of this species wrong?

The graph below shows some data from the early- and mid- 1990s showing how the abundance of Amphora pediculus was related to phosphorus.   The vertical lines on this graph show the average position of the boundaries between phosphorus classes based on current UK standards.   Records for A. pediculus are clustered in the “moderate” and “poor” classes, supporting my initial assertion that this species is a good indicator of nutrient-enriched conditions, but there are also samples outside this range where it is also abundant, so A. pediculus is only really useful when it is one of a number of strands of evidence.

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The relationship between Amphora pediculus and reactive phosphorus in UK rivers, based on data collected in the early-mid 1990s.  Vertical lines show the average boundaries between high and good (blue), good and moderate (green), moderate and poor (orange) and poor and bad (red) status classes based on current UK standards and the two arrows show the optima based on this dataset (right) and data collected in the mid-2000s (left).

If we weight each phosphorus measurement in the dataset by the proportion of Amphora pediculus at the same site (i.e. so that sites where A. pediculus is abundant are given greater weight), we get an idea of the point on the phosphorus gradient where A. pediculus is most abundant.   We can then infer that this is the point at which conditions are most suitable for the species to thrive.  In ecologist’s shorthand, this is called the “optimum” and, based on these data, we can conclude that the optimum for A. pediculus is 154 ug L-1 phosphorus.  The right hand arrow indicates this point on the graph below. However, I then repeated this exercise using another, larger, dataset, collected in the mid-2000s.   This yielded an optimum of 57 ug L-1 phosphorus (the left hand arrow on the graph), less than half of that suggested by the 1990s dataset.   There are, I think, two possible explanations:

First, the 1990s phosphorus gradient was based on single phosphorus samples collected at the same time that the diatom sample was collected (mostly spring, summer and autumn) whilst the mid-2000s phosphorus gradient was based (mostly) on the average of 12 monthly samples.  As phosphorus concentrations, particularly in lowland rivers, tend to be higher in summer than at other times of the year, it is possible that part of the difference between the two arrows is a result of different approaches.  (For context, in the 1990s, when I first started looking at the effect of nutrients in rivers, phosphorus was not routinely measured in many rivers, so we had no option but to do the analyses ourselves, and certainly did not have the budget or time to collect monthly samples).

However, another possibility is that the widespread introduction of phosphorus stripping in lowland rivers in the period between the mid-1990s and mid-2000s means that the average concentration of phosphorus in the rivers where conditions favour Amphora pediculus have fallen.   In other words, A. pediculus is tolerant of high nutrient conditions but is not that bothered about the actual concentration.   My guess is that it thrives under nutrient-rich conditions so long as the water is well-oxygenated and, as biochemical oxygen demand is generally falling, and dissolved oxygen concentrations rising (see “The state of things, part 1”), this criterion, too is widely fulfilled.   I suspect that both factors probably contribute to the change in optima.

But the second point in particular raises a different challenge:  We often slip into casual use of language that implies a causal relationship between a pressure such as phosphorus and biological variables whereas, in truth, we are looking at correlations between two variables.   Causal relationships are, in any case, quite hard to establish and the effect that we call “eutrophication” is really the result of interactions between a number of factors acting on the biology.   All of these simplifications mean that it is useful, from time to time, to look back to see if assumptions made in the past still hold.   In this case, I suspect that some of our indices might need a little fine-tuning.  There is no disgrace in this: the evidence we had in the 1990s led us to both to a conclusion about the relative sensitivity of Amphora pediculus to nutrients but also fed into a large-scale “natural experiment” in which nutrient levels in UK rivers were steadily reduced.   When we evaluate the results of that natural experiment we see we need to adjust our hypotheses.  That’s the nature of science.  As the sign on the door of a friend who is a parasitologist reads: “if we knew what we were doing, it wouldn’t be research”.

References

The 1990s dataset (89 records) is mostly based on data used in:

Kelly M.G. & Whitton B.A. (1995).   A new diatom index for monitoring eutrophication in rivers.   Journal of Applied Phycology 7: 433-444.

The mid-2000s dataset (1145 records) comes from:

Kelly, M.G., Juggins, S., Guthrie, R., Pritchard, S., Jamieson, B.J., Rippey, B, Hirst, H & Yallop, M.L. (2008).   Assessment of ecological status in UK rivers using diatoms.   Freshwater Biology 53: 403-422.

Not so Bleak Midwinter?

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Occasionally – just occasionally – the gods smile on us when we least expect it.  And Wednesday was one of those days: fieldwork on a glorious winter day in the Lake District without a cloud in the sky and barely a breath of wind.  The pleasure of being outside on such a day was offset slightly by the necessity of plunging my arm into freezing cold water at intervals, but the views of the mountains beyond Ennerdale Water more than compensated for these temporary discomforts.

The coldness of the water, today, offers me a link to a book I am reading, about the 19th century German scientist Alexander von Humboldt, a polymath who was ahead of his time in many ways, and whose writing pre-empted ecological thinking of the twentieth century.   One of his strongly held beliefs was that scientists could not really understand nature from a laboratory: they had to be outside, experiencing nature first hand.   That seems to be a fine New Year message in a world where ecologists seem to spend more and more time staring at screens, and their managers are increasingly reluctant to let them spend time in the field.

The ecology of lakes and rivers in this area in winter continues to fascinate me.   Look at the picture below: a stream bed at the coldest time of year that is covered with lush growths of algae in a range of hues, most strikingly the pink-red of the Rhodophyta Audouinella, complemented by the green and blue-green algae around it.  The first young olive-green filaments shoots of Lemanea, another Rhodophyta, were also apparent at a couple of the sites that I visited, and there were thick brown diatom blooms smothering many of the stones too.   These are all thriving at a time of year when either most nature has shut down for the winter or most natural historians have plonked themselves onto the sofa to watch Living World II rather than challenging the first clause in this sentence.  You decide.

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A riot of colour on the stony substrata of the River Ehen, a few kilometres downstream of Ennerdale Water, Cumbria, January 2017. 

One of Humboldt’s big concerns was that scientists saw the big picture (“naturgemälde”) rather than getting bogged down with details.   He was someone whose mind had been formed by the Enlightenment, when the necessity of cataloguing and classifying the diversity of nature was a primary concern.  However, he saw that this was not enough, and that one had to understand the connections between these different life forms, and between each of these and their environment.  He saw the natural world as a web of interdependencies, and humans as potential disruptors of the delicate balances that existed.

The problem we have in the modern age is balancing the need to see the big picture in focus without losing site of important details.  Or, as Ed Tipping said during a meeting at CEH last year: “we stick to the principle of simplifying to just short of the point of naivety”.   He had his tongue in his cheek but there is an important point here: the complexity of the natural world means that its secrets will only be yielded to those scientists who can keep their natural proclivity to get lost in detail in check.   At the same time, if we forget that those details are out there we may reach erroneous conclusions.  And, I fear, microscopic benthic algae may be ecology’s Sirens, sitting on submerged rocks and luring the unsuspecting into a world of taxonomic detail that is too rarely accompanied by profound ecological insight.

William Wordsworth, born in Cockermouth, just a few miles away from Ennerdale, was one of Humboldt’s readers.  He recognised the need to be outside experiencing nature applied as much to a poet as to a scientist and reacting against the dry, dissected knowledge that the Enlightenment encouraged.  His words offer a succinct conclusion for this first post of 2017, and encapsulate my resolution to be as holistic as possible in my thinking during the year ahead:

For was it meant
That we should pore, and dwindle as we pore,
For every dimly pore on things minute,
On solitary objects, still beheld
In disconnection dead and spiritless,
And still dividing and dividing still
Break down all grandeur …

William Wordsworth, The Excursion, 1814

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Lucky heather …

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The interior of Shetland’s Mainland is rugged and remote and almost completely lacking basic tourist infrastructure such as footpaths that most hikers take for granted.  We located the approximate position of our destination on the skyline using our map then set off across heather-covered blanket bog, slithering down peat hags and across small streams until we reached our destination.  This was not a good time to find that I had left an important part of my sampling kit back in the car.

I searched every pocket of my cagoule and rucksack but I could not find my bag of toothbrushes.   These are the basic sampling tool of every diatomist, perfect for removing most algae growing on the surface of submerged stones.   Yet here I was, in one of the most remote corners of the country,  facing a beautiful small loch, but without any means of collecting a sample.   Jon, my co-worker on this trip, looked around us: “can’t you use a piece of heather?”

And so that is what I did: I pulled up a few shoots of heather, gripped them between two fingers and used these, toothbrush style, to clean the brown film off the surface of stones.   I picked out a few leaves and stems out of the final suspension and poured this into my sample bottle.   Problem solved.

sampling_diatoms_with_heath

Using a piece of heather (Calluna vulgaris) to sample diatoms from a loch in Shetland, October 2016.  The top photograph shows Lamba Water, Mainland (photographed above), during the same sampling trip.

Several of the stones that I picked up from the littoral zone of Lamba Water had slippery, gelatinous tufts which, when examined closely with the naked eye could be seen to be made of bead-like filaments which I recognised to be the red alga Batrachospermum (see “Algae … cunningly disguised as frog spawn”).    Under the microscope, the beaded appearance resolved into tufts of branches arising from a single main axis which, at low magnification, looked like a bottle brush.   Most of my previous encounters with this genus have been in hard water but Lamba Water has relatively soft water (alkalinity: 7 mg L-1 CaCO3; conductivity: 117 mS cm-1) and a slightly acid pH (6.4) due to the surrounding peat which stained the water a dark brown colour.   Browsing through my Flora, I did notice that many of the species listed do appear to have very broad ranges for conductivity that suggest a low sensitivity for rock type compared to other types of algae.   I would not like to make too much of this as the data in the Freshwater Algal Flora of the British Isles are relatively sparse, but it is something that would be interesting to pursue in the future.

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A tuft of Batrachospermum on a submerged cobble in the littoral zone of Lamba Water, Shetland Isles, October 2016.  Scale bar: approximately 1 centimetre.

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magnification; right hand image at 400x (scale bar: 20 micrometres (= 1/50th of a millimetre).

One of the characteristics of Shetland is a very diverse geology packed into a relatively small area and the following day’s excursions took us to a very different lake on the other side of Mainland.   This was Loch of Girlsta, much deeper than Lamba Water (it is the only loch on Shetland with a population of Arctic Charr, I understand) and influenced by a narrow band of limestone (although most of the catchment seems to be the standard Shetland blanket bog).   By this time, we were having to contend with rain as well as strong winds and our time on site was limited.  I did, however, have a chance to spot some dark brown hemispherical colonies, mostly 3-4 mm in diameter, on some of the submerged stones.  Although the hemispherical colonies first made me think of Rivularia, when I was back in warm and dry conditions and had a chance to look at it under my microscope, it turned out to be Tolypothrix, the cyanobacterium that we last encountered in Ennerdale Water (see “Tales from the splash zone”) which is, chemically, quite similar to Loch of Girlsta, though perhaps with less peat in the catchment.   Both are in catchments with so little human influence that algae need to resort to nitrogen fixation in order to obtain the nutrients that they need to grow.

As an illustration of the extraordinary geological and ecological diversity that we encountered in such a small area, Loch of Benston, the final loch that we visited, was almost entirely underlain by limestone, and had extensive Chara beds.

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Colonies of Tolypothrix cf distorta (arrowed)) on rocks in the littoral zone of Loch of Girlsta, Mainland, Shetland Isles, October 2016. 

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Microscopic view of a false branch of Tolypothrix cf distorta from Loch of Girlsta.  Scale bar: 10 micrometres (= 100th of a millimetre).

Back on the mainland (the British mainland, that is, rather than Shetland’s Mainland), it was the autumn colours that struck me, after a few days north of the treeline on Shetland.   The drive back south from Edinburgh took me through the wonderful array of brown, red and yellow hues of the Borders and Durham, itself, always looks spectacular at this time of year.   The diatom samples that I collected with those bunches of heather now need to be processed and, I’m sure, there will be more tales from the northern isles to tell once I’ve had a chance to look at these.

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Autumn colours on the Durham riverbanks, October 2016.

 

The power of rock …

In my recent post on Ennerdale Water I referred to the interaction between geology and man in shaping the characteristics of a lake (see “A lake of two halves …”).   As I was writing, I had in mind some famous early work on this topic by Harold (“W.H.”) Pearsall, a botanist who made some of the first tentative steps towards linking patterns and processes in lake ecosystems, whilst working at the universities of Leeds and Sheffield.   He had visited many of the lakes since boyhood and co-opted his father as a field assistant to cycle around the Lake District performing the surveys that formed the basis of this paper.

Pearsall had noted differences in the types of plants growing in the various lakes in the region, and attributed these differences to the geology of the surrounding land.   He took this idea one step further by also suggesting that the lakes became modified as they increased in age, illustrating this by arranging the English Lakes into an “evolutionary sequence”, with Wastwater and Ennerdale Water representing the least evolved, and Windermere and Esthwaite Water representing the most advanced.   His first proposition is now well-established amongst those who study lakes; the second is also generally accepted (I remember writing an essay entitled “Lakes are temporary features of the landscape” as part of my A-level Geography course), although his use of the English Lakes to illustrate this is not.

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The lakes of the English Lake District, arranged in the evolutionary sequence proposed by Pearsall: 1: Wastwater; 2: Ennerdale Water; 3: Buttermere; 4: Crummock Water; 5: Hawes Water; 6: Derwent Water; 7: Ullswater; 8: Bassenthwaite Lake; 9: Coniston Water; 10: Windermere; 11: Esthwaite Water.

The graph below makes Pearsall’s case, using his own data (note that his records for Hawes Water refer to the small natural lake that was submerged to form the current Haweswater Reservoir).   The left hand axis shows the proportion of land in the catchment of each lake which was under cultivation (at the time of his study) steadily increasing as we move through his evolutionary sequence.   The right hand axis shows how proportion of the shoreline of each lake that was rocky (down to a depth of 30 feet – 9.2 metres) steadily decreases through the sequence.  He pointed out that both the amount of cultivatable land and the character of the shoreline depended largely on the character of the surrounding country.

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A graphical representation of Table 1 in Pearsall (1921): “Effects of erosion”.  Lakes are arranged in order of Pearsall’s “evolutionary sequence”.

The next graph shows the same sequence of lakes (excluding Hawes Water) but with the average values of the Lake Trophic Diatom Index (TDI) plotted on the Y axis, and with lakes sub-divided into those with low alkalinity (deriving most of their runoff from the Borrowdale Volcanics and associated hard rocks, including the Ordovician granite discussed in the post about Ennerdale) and those with moderate alkalinity (associated with softer rocks to the north and south of the Borrowdale Volcanics).   This confirms the primary role of geology, with Pearsall’s “primitive” lakes underlain by the Borrowdale Volcanics whilst the more “evolved” are associated with the softer rocks.  Within each category there is an upward trend, rather more pronounced in the moderate alkalinity lakes, as we move through Pearsall’s sequence.  I suspect that this represents the interaction between geology and man, with higher TDI values associated with lakes where there is more agriculture and greater population density.   These factors may, in turn, combine to affect the physical factors within the lake over time, but the implication that a “primitive” lake such as Ennerdale Water might one day “evolve” to have characters similar to those of Windermere is no longer accepted.   On the other hand, he did set up some testable hypotheses that kept freshwater ecologists occupied for a long time subsequently.  As Lao Tzu reminded us: “a journey of a thousand miles begins with a single step”…

pearsall_versus_ltdi

Average lake TDI values (using data from Bennion et al., 2014) for Lake District water bodies, arranged by Pearsall’s evolutionary sequence (no data for Hawes Water).   Open circles are low alkalinity lakes; closed circles are moderate alkalinity lakes.

References

Bennion, H., Kelly, M.G., Juggins, S., Yallop, M.L., Burgess, A., Jamieson, J. & Krokowski, J. (2014).  Assessment of ecological status in UK lakes using benthic diatoms.  Freshwater Science 33: 639-654.

Clapham, A.R. (1971).  William Harold Pearsall.  1891-1964.  Biographical Memoirs of Fellows of the Royal Society 17: 511-540.

Pearsall, W.H. (1921).  The development of vegetation in the English Lakes, considered in relation to the general evolution of glacial lakes and rock basins.  Proceedings of the Royal Society of London Series B 92: 259-285.

A lake of two halves …

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I have started this post in the same way that I started the previous two posts: with one of a series of pictures that I took from Kirkland whilst driving away after fieldwork in Ennerdale Water and the River Ehen earlier in March and noticing the rather spectacular view up the valley. This post, like those, will focus on the microscopic life of the lake but it pays to pause for a moment – as I did on my drive away from Ennerdale – to look at the landscape, and contemplate how the features that are apparent in this panorama shape the properties of a lake that are less obvious to the casual observer.

The picture shows a view across Ennerdale Water towards some of the highest peaks of the Lake District, with Great Gable prominent in the background. What we can also see is a transition: the foreground consists of softer features and more gentle slopes; the background is rugged, steep scree-covered fells. Somewhere, approximately at the point where the hills in the centre left of the picture fall into the lake, the rock type changes. In the foreground, the underlying rock is Ordovician mudstones and sandstones; beyond this, the rocks are formed from a granite intrusion resulting from volcanic activity. This activity also took place in the Ordovician period, but the rock is much harder than the sandstones and mudstones that underlie the foreground.

Most of the features that I have written about in Ennerdale Water are from the zone underlain by the granite but I also visited the north-western end of the lake, where the mudstones and sandstones predominate and the algae that I found attached to the rocks here were conspicuously different. Many of the submerged stones were covered with green filaments which, in turn, were overgrown by diatoms – mostly Tabellaria flocculosa and species of Fragilaria. The green filaments, in turn, had trapped a lot of fine sediments, presumably deriving originally from the sandstones in the catchment. Under the microscope, the green filaments resolved into a mass of Spirogyra filaments, with their distinctive helical chloroplasts, along with Bulbochaete and a few strands of other genera. The algae in this corner of the lake reminded me, in fact, of the algae that I am used to seeing in the River Ehen, just downstream from the lake outfall.

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A submerged cobble in the littoral zone of Ennerdale’s north-western corner (left) with (right) two filaments of Spirogyra at high magnification, each with two ribbon-shaped chloroplasts arranged in helices. Scale bar: 20 micrometres (= 1/50th of a millimetre).

Those of us who study freshwaters know that geology has a big influence on the types of plants and animals that grow in a water body – it is probably the strongest natural factor excluding situations where there is a saline influence. The interesting point about Ennerdale is that geology not only has an effect on the lake as a whole (most of the water deriving from the granitic fells that make up the catchment), but it also has subtle effects around the margin, particularly on those algae that are growing directly on rock surfaces.

But it is not quite as simple as that. Look at the photograph at the top of this post. The foreground – the land underlain by Ordovician mudstones and sandstones – is improved pasture. The topography is such that a farmer can get a tractor onto the fields and spread some manure or fertiliser a couple of times a year which, in turn, means the land can carry more livestock. A little of those nutrients may find their way into the small streams that drain into the lake and this, too, may be having an effect on the algae. On the fells beyond, only rough grazing is possible. In other words, however hard we try to separate the effect of man from natural factors, we also have to remember that the landscape, itself, shapes the way that man uses the land. And that, in turn, influences the ecology of the lake.

I should emphasise that the algae in the north-west corner of Ennerdale Water do not suggest any malign effects from those parts of the catchment that drain into the lake here. My point is just that they are different and that the change in geology along the lake may be one factor driving this difference. It is quite subtle, the water that flows into the lake is soft and it is only very slightly less soft near the outfall. But it is enough to have an influence on the ecology of the organisms that live around the edge of the lake. The story of the lakes of the Lake District has told in terms of the rocks that form each of their catchments. What is interesting in Ennerdale Water is that we can see some of those effects of geology within a single water body.

 

Tales from the splash zone …

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Mougeotia was not the only alga that intrigued me in Ennerdale Water during my recent visit (see “Fifty shades of green …”).   Alongside the green tufts, and also just at water level, there were dark spots and patches on the rock that yielded to a gentle scrape with my finger nail.   The colour suggested Cyanobacteria, so I popped a little into a sample bottle to examine later.

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Patches of Stigonema mamillosum and Scytonema cf crustaceum growing at water level on granite boulders on the southern shore of Ennerdale Water, October 2016.   The scale bar is approximately one centimetre.

The surprise, when I looked down my microscope, was not that it was cyanobacteria, but that there were at least three genera mixed together.   The first of these was Scytonema cf crustaceum, characterised by a thick brown sheath and the presence of double “false branches”, formed when both ends of a broken filament continue to grow and, eventually, burst out of the sheath (see “Poking around amongst sheep droppings”).   In the image below you can see the narrow blue-green filament of cells within the much broader sheath.

Also present was Stigonema mamillosum, a representative of a genus with a more advanced morphology than other Cyanobacteria, with branched filaments that can be several cells thick (see “More from the River Atma”), and Calothrix sp., which has tapering filaments in a much thinner sheath.   All three genera have the capability to fix atmospheric nitrogen, so thrive in nutrient-poor habitats such as Ennerdale (see also “Both sides now …”).   Calothrix, in addition, is able to scavenge phosphorus from the water, releasing enzymes from the long colourless hairs (just about visible to the right of my photograph).

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Scytonema cf crustaceum from the littoral zone of Ennerdale Water, October 2016.   Scale bar: 20 micrometres (= 1/50th of a millimetre).

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Stigonema mamillosum and Calothrix sp from the littoral zone of Ennerdale Water, October 2016.   Scale bar: 20 micrometres (= 1/50th of a millimetre).

I found superficially-similar growths on rocks on the north east side of the lake, but it was clear, even from the appearance in my sample bottle, that this was something different.  The tangles of filaments from the southern shore of the lake, where I had started, had no other form when suspended in water, than an amorphous blob.  However, the material from the north-east side formed distinct “tufts”.   The superficial similarities continued when I peered down the microscope: once again the chains of blue-green cells were enclosed within a thick brown sheath and, once again, there were false branches.  This time, however, the false branches were single, not double, and formed acute angles with the “parent” filament, rather than the near perpendicular double false-branches that we saw in Scytonema.   These features are characteristic of Tolypothrix (Brian Whitton suggests T. distorta) and it is these acute branches that impart the “bushy” appearance to the colony.   Like the cyanobacteria that I found on the southern shore, Tolypothrix is capable of nitrogen fixation so, its presence here is confirmation of the nutrient poor status of the lake.

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Tolypothrix distorta (var. penicillata?) from the littoral zone of Ennerdale Water, October 2016.  a: low power view of a tuft of filaments (approximately 5 mm in length); b: filaments showing single false branching (x100 magnification); c: medium power (x400) view of false branch.   Scale bar: 20 micrometres (= 1/50th of a millimetre).

Nitrogen-fixation involves busting apart the strong bonds of atmospheric nitrogen in order that the cell can use the nitrogen to build the proteins that it needs to function.  This requires a lot of energy and, as a result, the investment is only worthwhile if other sources of nitrogen are very scarce.   That energy could, otherwise, be diverted to more useful purposes.  The presence of so many different types of nitrogen-fixing organism around Ennerdale is sending out a clear sign that this is a nitrogen-poor habitat.  Algae such as Mougeotia cannot fix nitrogen, and they presumably have to make other sacrifices (a slower growth rate, perhaps?) in order live alongside these Cyanobacteria.   As far as I know, the energy costs of scavenging phosphorus from organic compounds in the water has not been calculated but the same principle must apply: the cell has to create more of the phosphatase enzymes than normal, in order to produce a surplus that can leak through the cell membrane and react with organic molecules in the vicinity.   Again, that all requires energy that can be used for other purposes.  In contrast to nitrogen fixation, this is an ability that Cyanobacteria share with some other algae including, possibly, Mougeotia.

Finding these algae in a one of the most remote lakes in the country, where the impact of humans is very low, I start to wonder how many of our other lakes would have had such an assemblage of organisms before agricultural intensification and the rise in population numbers.   Nature is, naturally, parsimonious in the way it distributes the inorganic nutrients plants need.   Necessity, we are told, is the mother of invention and the diversity we see in near-pristine habitats such as Ennerdale Water is as much the result of plants and algae finding their own individual solutions to grabbing their share of the scant resources available.   There’s enough here for a BBC natural history documentary … apart from an anthropomorphic mammal or bird.  Which is another way of saying … no chance …

How to make an ecologist #9

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One of the minor pleasures of this year has been digging out old 35 mm slides, scanning them into a digital form and then using these to trigger memories of the twists and turns in my professional life (see “How to make an ecologist #8“).   I have not done this for some time, largely because other topics have seemed to be a higher priority to write about.   None more so in recent weeks than the forthcoming referendum on the UK’s membership of the European Union.   A serendipitous moment, however, led me to two boxes of slides documenting two periods of fieldwork in Italy in 1988 and, through these, to remember how difficult travelling around Europe used to be before the advent on the single market.

I visited Italy twice in 1988, as a postdoc on a project looking at Holocene vegetation history.  On both occasions we drove from northern England in a four wheel drive vehicle loaded with equipment.   I have two strong memories of those journeys: the distances we covered (Calais to northern Italy in a single day) and the hassle at every national border we crossed.   In those pre-open market, pre-Schengen agreement days we not only had to show passports at each frontier, we also had to queue up with the lorries and other commercial vehicles and go through a full customs check.   This had also entailed travelling to the Chamber of Commerce in Leeds shortly before we left to get a “Carnet de Passage en Douane”.   This was a document that allowed us to temporarily import our equipment for the duration of the project without the need to pay any customs or taxes at the border.   It entailed leaving a bond in the UK, which was returned if our Carnet de Passage was signed and stamped at every border to show that we had brought out the same as we had taken in a few days previously.  My memory is that the customs checks were not especially thorough; indeed, the officials rarely looked inside our vehicles.  But we did have to sit in the long queues awaiting our turn in order to get our carnet de passage signed.

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Fieldwork in Italy during 1988: sampling surface sediments from a lake somewhere in the Appenines with Brian Huntley during our spring visit (left) and using a Livingstone corer to collect a sediment core in the fens beside Lago di Monticchio in southern Italy in September 1988.

Almost thirty years later, I take for granted that I can travel around Europe for pleasure or business with almost no constraints.   In my own small way, I run a business that depends, to some extent, on “exports” to the European Union.   I had forgotten, until I dug out these memories, just what that entailed.  The irony is that establishing a tighter control on our borders will, almost inevitably, make crossing those same borders slower and will generate extra paperwork, particularly for those of us who travel on business.  Of course, once we are in Europe, the open borders will mean that our progress across the continent will not be impaired.   And the stated aspiration of the “leave” campaigners is that there will be a free trade agreement between UK and the EU which will mean that we can continue to do business.

Like much of the rhetoric that surrounds the EU referendum, the reality is less certain than the protagonists suggest.  My own view is that leaving would be foolish but, if that is the outcome of the referendum, then a free trade agreement probably will be achieved, possibly on the lines of that currently enjoyed between Norway and the EU.   Brexiters such as Johnson, Farage and Duncan Smith talk glibly of this as if a deal strongly weighted in the UK’s favour was no more than a formality.   This is naïve: my own belief is that a free trade agreement will be contingent on the UK maintaining the “level playing field” for business which, in turn, will mean staying signed up to, amongst other things, key employment and environmental legislation.   It will also mean paying some money to Brussels to support the implementation of those aspects of EU law, and any other parts of the EU’s activities that are deemed beneficial (access to research funding, perhaps?).   That is something that the Brexiters have been rather quiet about over the past weeks.

Of course, I regard the prospect of the UK staying signed up to EU environmental legislation, in particular, as a small crumb of comfort in these worrying times.  That is partly down to self-interest, as helping with the implementation of EU legislation is a major part of my business.  But it is not just self-interest.  As I have written before (see “What has the EU ever done for us?”), I do genuinely believe that we get stronger environmental protection by being part of the EU than we would if we depended solely on Westminster and Whitehall.

I don’t expect that I will need a Carnet de Passage any time soon.  But remembering how things were, in the days before the European Economic Community morphed into the European Union and promoted genuinely free trade, is enough to remind of just how much we stand to lose after next week’s referendum.

Pinus_pinea_Italy88

A clump of umbrella pine, Pinus pinea, on a hillside, photographed during fieldwork in 1988.