Getting rid of all this green crap …

Newspaper reports that David Cameron is “going round No. 10 saying ‘we have to get rid of all this green crap’” in reference to the environmental taxes on energy bills have been played down by Downing Street.  Whether true or not, they do point to a very real challenge to politicians of all hues as they struggle for sustainable economic growth.   A central tenet  of the free market economics that David Cameron and his conservative predecessors espouses is freedom of choice yet much environmental policy necessarily necessitates a command-and-control approach to governance.   We manage the aquatic environment by regulating the activities of businesses (backed up by the threat of prosecution) and we manage landscapes by packages of subsidies to farmers.   Moreover, much of the legislation comes from Brussels, which is itself a threat to our national sovereignty, if many politicians on the right are to be believed.

At a superficial level, Cameron’s alleged comments can be seen as the latest salvo in his ongoing campaign to appease the right-wing of his own party and gain ground in the battle with UKIP.   The energy companies are, themselves, playing a devious game by focusing attention on the taxes rather than the other elements of people’s utility bills.   But it is too easy to just dismiss this as political wrangling.   How, in the midst of a recession, do we find a balance between the need for sustainable use of resources in the long term, and to ease the burden on hard-pressed householders?

My own travels have convinced me that sustainable environment policies can’t exist without either strong central government or a healthy economy.  Politically, of course, this is the no-man’s land between libertarian and socialist ideologies that few outside of Scandinavia seem to have achieved.  The Scandinavian example is not straightforward because their relatively low population densities ease the pressure on the environment, when compared to more densely-populated regions of Europe, including the UK.

That the price we pay for a healthy environment might be a major issue in the next election points to a further challenge.  That politicians can present this as irrelevant or too expensive itself is a sign that the environmental profession is doing a poor job of communicating benefits to the wider public in terms that they can understand.   We can win over individual groups of stakeholders (see Bring on the Dambusters  …) but, too often, we act as a priesthood, taking a “tithe” of public spending as of right and dispensing it on projects according to criteria that mean nothing to all those householders struggling to pay their energy bills.   Like him or loathe him, David Cameron is one of the most astute politicians I can remember, and if he would not contemplate taking on the green lobby unless he had done his homework first.

The River Ehen in November

There is a gravel bank on the inside of the meander at one of our sites on the River Ehen and we get a pretty good idea of how high or low the river is as soon as we see how much of this bank is exposed when we arrive.   When the river is low, there is always a zone just above the water line where many of the stones are covered with a bright green film of algae.

Under the microscope, this turns out to be composed of narrow unbranched filaments of an alga called Klebsormidium flaccidum, a member of a small genus of green algae that are often found in habitats that are not fully submerged or only periodically damp.   A single chloroplast encircles half or three-quarters of the circumference of each cell.


A stone (about 20 cm across) covered with Klebsormidium flaccidum on a gravel bank beside the River Ehen, November 2013

As is often the case with filamentous green algae, naming the genus to which it belongs is relatively straightforward but deciding the name of the species is much more difficult.   The problem is that there are so few diagnostic characters available to differentiate one species from another and that the algae are naturally variable (think about how different a houseplant looks when grown in the shade to on a well-lit windowsill).   Fabio Rindi, who wrote the key in The Freshwater Algal Flora of the British Isles, suggested that his key was provisional and that we should really grow the species in culture and extract its DNA if we want to be sure of it’s identity.

This all creates a problem for ecologists who want to use algae to infer properties from the environment as much of the literature about these species is scattered liberally with errors made in good faith by earlier generations  of biologists.   We have to pick our way through their conclusions with great care and, regrettably, often find that generalisations based on the properties of the genus are the best we can do.


A filament of Klebsormidium flaccidum from the River Ehen, November 2013.  The scale bar is 10 micrometres (= 1/100th of a millimetre).


Rindi, F., Guiry, M.D. & López-Rautista, J.M. (2008).  Distribution, morphology and phylogeny of Klebsormidium (Klebsormidiales, Charophyceae) in urban environments in Europe.  European Journal of Phycology 44: 1529-1540.

More about ecosystem services

The ideas discussed at last week’s conference on Ecosytem Services are still reverberating through my mind, particularly as I try to reconcile the competing needs of different water users.  It is not enough just to argue that managing towards a healthy “good status” ecosystem will bring undoubted benefits to all, as I tried to illustrate using the competing needs of wildlife and rowers on the River Wear in Durham.   Hard-line ecologists tend to think that the Water Framework Directive places an obligation on governments to manage towards Good Ecological Status in all water bodies but, in fact, there are clauses in the Directive which require governments to balance “costs” and “benefits”, which brings complications to any debates.

With these thoughts in mind, I put together a chart to illustrate how different activities which are grouped under the broad heading of “cultural ecosystem services” may relate to the general Water Framework Directive objectives of Good Ecological Status.  “Recreation” is one “cultural service” that we obtain from ecosystems, and “contact water sports” should, in theory, be one beneficiary of any investment in improved water quality (swimmers and canoeists have no desire to swallow mouthfuls of polluted water).  But what about those who just want to walk on the banks of lakes and rivers and enjoy the view?   I suspect that, so long as large-scale landscape features are intact (overhanging vegetation, some meanders) and the river does not have an unpleasant smell, the public would probably accept less than good status (or, at least, not see the need to spend the extra needed to achieve good status).


A diagram illustrating the relationship between recreational activities and ecological status.  The EU’s Water Framework Directive expresses the quality of an ecosystem in terms of five classes, from “high” to “bad”, with good status being the theoretical target that all water bodies should achieve.

And what about angling?  This is an activity where views will differ, even within the fishing community.   Game fishermen, in pursuit of salmon and trout, should benefit from efforts to improve rivers.  However, many coarse fish are less fussy about their habitats and there are even anecdotal accounts of fishermen complaining that the angling is poorer after water quality improvements.   Many types of pollution are the equivalent of spraying manure onto a pasture, fertilising the water and thereby enabling it to support a larger mass of fish.   Specialist carp fishermen represent the extreme position: their target species love rooting around in the bottom of shallow nutrient-rich lakes and ponds, so it is possible that they might even be happy with conditions  well below good status.   I might be wrong, but it would be interesting to compare angler’s perceptions of river and lake quality with the data that our current status assessments are based.   This is not to say that any particular user group is “right” or “wrong”, only that we may need to approach discussions about benefits of healthier ecosystems with our eyes wide open.

Super eruption launched algae army into the sky …

I chose this headline from over the rather more measured “could volcanism have spread organisms?” to grab your attention.    The story behind the lurid headline links to one of the hot issues in the ecology of microscopic organisms – how the same species can be found in isolated habitats thousands of miles apart.   One of the big discoveries in recent years is that, in many cases, they are not, in fact, the same species, but closely-related forms which were confused until very recently, because we assumed they were cosmopolitan and, consequently, assumed that the books written in Europe could also be used as far away as Australia to identify algae.   The results, inevitably, confirmed that many algae were cosmopolitan.

The reality is more complicated.  Careful studies have shown that many of these “species” are, in fact, complexes composed of several true species, each with very localized distributions.  However, I can also point to several examples of algae that we know to be truly cosmopolitan, which means that questions about how these disperse across enormous distances are still highly relevant.   Several hypotheses have been put forward but Steve Drury’s blog points to one more possibility.

Some of my early research was on volcanic lakes in Italy; these were set beautiful locations surrounded by mature forests but the volcanoes beneath us were dormant, not extinct.   Had any of these erupted, tens of thousands of years of accumulated sediments would have been thrown into the air.   Much of this sediment was composed of the remains of organisms that lived in and around the lake.   The suggestion is that these could have been thrown up into the stratosphere and then carried hundreds of kilometres from their origin.   Most of the diatoms would have been no more than empty silica shells but some – a tiny proportion – would have been viable.  A tiny proportion of these would have survived the heat of the eruption and the exposure to the atmosphere that followed, and a tiny proportion of these would have fallen onto freshwaters where they could start to grow again.  The chance of any single cell surviving all this was infinitesimally small, but evolution is a game of very long odds.


Van Eaton, A.R., Harper, M.R. & Eaton, C.J.N. (2013). High-flying diatoms: Widespread dispersal of microorganisms in an explosive volcanic eruption. Geology 41: 1187-1190.

Pike, J. (2013). Of volcanoes and diatoms. Geology 41: 1199-2000.


Diatoms and the Great War

I’ve written a lot about diatoms over the past few months, trying to illustrate their beauty and diversity, as well as their importance in aquatic ecosystems.   They are extremely abundant in freshwaters and oceans around the world and make an important contribution to the total primary productivity on the earth.   Just occasionally, in the past, they have become so abundant that their accumulated dead shells have formed distinct geological strata.  These were first discovered in northern Germany in the 1830s and people quickly realised that this soft sedimentary rock, known as Kieselguhr or diatomite, when ground to a fine powder, had many uses.   The mild abrasive properties, for example, led to its inclusion in toothpaste, and it can also be used as a natural pesticide (we have used it to control red mites on our chickens).

In the 1860s, the Swedish engineer Alfred Nobel was experimenting with a new explosive material, nitroglycerin, which he thought had many possible applications in mining and quarrying.  However, nitroglycerin was extremely unstable and, therefore, dangerous to use.  Nobel found that if he mixed three parts of nitroglycerin with one part of Kieselguhr, the result was all the explosive power but now in a much more stable form.   He christened his new invention ‘dynamite’.

The rest, as they say, is history.  Except that today is the anniversary of the end of the Great War which led me to the somewhat oblique realisation of the role of these tiny but fascinating organisms in the carnage of warfare.   In 1914 Europe split into two factions and spent the next four years lobbing enormous quantities of high explosives at one another.   Not all was dynamite but it is sobering to remember how Nobel’s original hope of creating an  explosive that was safe to handle contributed unintentionally to the toll of death and destruction.

Bring on the Dambusters …

Mild annoyance lies behind this post.  I’m writing as I travel home from a two day conference, organised by the Chartered Institute of Ecology and Environmental Management with the title ‘Ecosystem Services 3: Rivers – A Framework For Action’.  The meeting had several interesting papers but, at times, lacked a hard critical edge, exemplified by the following example:

Two of the early speakers commented on the problems of physical modification of rivers, noting that in-stream structures such as weirs often present serious obstacles to the migration of salmon and other migratory fish.   In theory, you should be able to construct fish passes around these weirs so that the fish are not obstructed.  In practice, however, many fish passes are not particularly successful.   ‘Why not’ suggested one questioner after the talk (representing Natural England, I think), ‘just remove the weirs altogether and restore natural flow regimes.’   This suggestion was greeted with applause and even a few ironic cheers from parts of the audience.

About six months ago, however, I joined the local rowing club in Durham. ‘Recreation’ is a ‘service’ that society gets from our rivers, just as much as nature and wildlife, the primary focus of interest for this audience of conservationists.   Rowing here depends upon the weirs across the River Wear (you can see one of them in the classic view of Durham Cathedral which I posted on 29 July. (This view, itself, could be classified as an ‘aesthetic’ ecosystem service).  There are about 500 members of the rowing club and, at a guess, between 500 and 1000 students in University and College crews.  That’s a huge constituency whose interests are in conflict with the ambitions of many conservationists.


Rowing on the River Wear, July 2013. 

I had come to the conference to see how this type of conflict of interest would be resolved, and was a little surprised to see how little it featured.  Only three of the 18 speakers addressed the issue of trade-offs between different ecosystem services and only half made any reference to public participation or stakeholder engagement at all.  I heard a good example of constructive engagement with anglers on the River Itchen during a workshop session but this was a situation that could be sold as a ‘win-win’, with both anglers and conservation benefitting.  For the most part it was conservationists talking to conservationists without anyone to challenge their assumptions.   I left feeling with a feeling that life out there in the real world may not always be this cosy.

Red algae in the River Ehen

It has been a while since I have had a diorama to show in my blog but I was inspired by the lush growths of Audouinella in the River Ehen back on 12 October (“at last … a red alga that is really red”) and, unhappy with how my previous attempt to portray Audouinella had turned out (so bad, in retrospect, that I am not giving you the link), set to work with pencil, paint and pastel again.


A three-dimensional representation of the Audouinella-dominated community in the River Ehen, October 2013.   The pinkish-red filaments of Audouinella form a dense matrix of filaments within which we can see colonies of the diatom Gomphonema truncatum on the left (with Achnanthidium minutissimum as an epiphyte) along with some chains of another diatom, Tabellaria flocculosa, on the right.  Filaments of the cyanobacterium Heteroleibleinia rigidula can be seen as epiphytes on the Audouinella.

Notice, in the picture, how the Audouinella has a few short side-branches which end in long, colourless hairs.  These, we think, are adaptations that exude enzymes and which allow the alga to extract phosphorus from organic matter in the river.   And note how the different diatoms all have distinct habitats within the mass of Audouinella filaments.   When we prepare diatoms for microscopy, we pay homage to the statistical gods and strive for a random strew of diatoms across our slide.   This is, however, far from the situation in the river itself, where Tabellaria and Gomphonema seemed to occupy different niches within the Audouinella.   Note, too, how there are no reproductive bodies on these filaments, in contrast to those I photographed back in February.

My dissatisfaction with my earlier diorama was partly my failure to capture the structure of the chloroplasts.  It was hard to reconcile what I could see under the microscope with the description in the Flora of “several parietal ribbon-like chloroplasts”.  The ones I could see were far from “ribbon-like”.  I checked other Floras without adding much to my understanding of the freshwater forms then, for contrast, I looked at the descriptions of the 33 marine species of Audouinella found in Britain and Ireland.  These seem to have a range of chloroplast forms, from a single, lobed chloroplast to many discoid chloroplasts.  There was, however, a suggestion that, in some species at least, the single chloroplast fragmented into several smaller chloroplasts as the cell aged, which might explain why I could see several non-ribbon-like chloroplasts in my specimens.   I’m still not entirely happy with my representation of the Audouinella but, having spent several hours on this image, it will have to do for now. Maybe I should return to the subject in the spring, when the carpospores re-appear?


Dixon, P.S. & Irvine, L.M. (1977)  Seaweeds of the British Isles Volume 1 Rhodophyta Part 1 Introduction, Nemaliales, Gigartinales.  British Museum (Natural History), London.

The highs and lows of microscopy in the field

My two recent posts which dealt with rapid assessment using algae both largely ignored the elephant in the corner of the room: the need for a microscope to identify the organisms we find.   “Rapid assessment” is protracted by the need to bring samples back to the laboratory in order to check their composition.   I mentioned Rick Battarbee’s use of a field microscope in my post of 29 October, so perhaps we should look at this idea in a little more detail?

I have had a field microscope for a few years now.  It is a Pyser-SG1 (which looks remarkably similar to the McArthur-type field microscope now available from Brunel Microscopes.   It is an inverted microscope (i.e. the objectives are below the slide) with a built-in light source, and is very useful in the field.  It lacks a condenser or field diaphragm, making control of the light source difficult, but this is rarely a major problem.  It is great for field trips with students, when I have to persuade students that a brownish smear on a submerged rock really is a living organism.  The biggest problem, in practice, is fiddling around with slides, Pasteur pipettes and cover slips in anything other than perfect weather conditions.


Left hand image: my Pyser McArthur-type field microscope.  The turret contains 4x, 10x and 40x objectives which, combined with the 10x eyepiece, gives magnifications up to 400x.   Right hand image: using my field microscope on a field course in County Mayo, Ireland, in 2008.

The major disadvantage is that the discipline itself is not focused on field identifications.   My field microscope weighs 1270 grams, a little heavier than my digital SLR.   However, the standard Flora of the freshwater algae of Britain and Ireland weighs in at a hefty 2830 grams, substantially more than the laptop on which I am writing.  This book does not include the diatoms; identification of these requires you to pack another 2795 grams into your rucksack.   I have to rely on memory as the type of portable, accessible field guides that are available for many other groups of organisms are simply not available for the algae.   Progress with algal-based rapid assessment methods will almost certainly require better field guides.  I have made a start on a booklet for the identification of the larger algae, and had some positive comments from those who have used it.  Maybe I can condense the most important taxa onto a fold-out laminated sheet, such as those developed by the Field Studies Council?  Or maybe we could put the key information into an app, so that it can be accessed via a smartphone or tablet?   Think outside the box …


The two hefty identification guides I mention are:

Hofmann, G., Werum, M. & Lange-Bertalot, H. (2011). Diatomeen im Süsswassser-Benthos von Mitteleuropa.   A.R.G. Gantner Verlag K.G., Rugell.

John, D.M., Whitton, B.A. & Brook, A.J. (2011).  The Freshwater Algal Flora of the British Isles.  2nd Edition. Cambridge University Press, Cambridge.