Farewell to 2016

wordle_2016

Has there been a year in my lifetime quite like 2016?   The possibility that the UK might leave the EU was alive at the start of the year, but few seemed to think that it was likely to actually happen. And Donald Trump was a cartoon character at the fringes of the race for the US Presidency.  Yet here we are, as the sun sets on the last day of the year, living in a UK that has voted – narrowly – to leave the EU and 20 days away from President Donald Trump’s first day in office.   The phrase “post truth” seems to have established itself in the English language, encapsulating the sad truth that the veracity of figures quoted by politicians, or emblazoned on the sides of their buses, is less important than their impact on target audiences.

Michael Gove’s comment just before the referendum that “people in this country have had enough of experts” puts the year into perspective.  He was referring, particularly, to the dire economic forecasts in the event of a vote to leave the EU but the comments hit much wider.   Most environmental scientists are engaged, to some extent in predicting outcomes depending upon particular interventions and we are trained to understand and articulate the uncertainties associated with these predictions.   It is the foundation of responsible decision-making. Yet it also means that we are easy meat for ideologically-driven politicians who can latch onto either the uncertainties themselves, or on differences between predictions, in order to push their own agendas.

I have a mote of sympathy for Gove’s comment.  Environmental scientists, in particular, can revel in the complexity of systems and deploy powerful statistical techniques that render outcomes inexplicable to non-specialists.  Being able to communicate the state of the environment to wide audiences is, in my opinion, in danger of becoming a lost art.   This is a point that I have tried to make in this blog in both 2015 and 2016 (see “The democratisation of stream ecology?”) and will continue to push in 2017.   This is not to pretend that the environment is not complex; or that there are not nuances which may be missed by a superficial or rapid analysis.  It is, rather, recognition that we need to pay particular attention to aspects of the environment to which non-specialists can relate if we are to produce evidence that is resistant to the guile of the political classes.

My word cloud for 2016 is similar to my 2015 word cloud, with “see” and “algae” both prominent, reflecting what is, I hope, the core business of this blog.   It was algae that put oxygen into the atmosphere in the first place, and which play a major role, still, in regulating affairs on this planet.  We may marvel at nature as presented by David Attenborough on Living World 2, but it is important that we do not forget the important role that nature’s “back room staff” play in the web of life.  The danger of TV natural history documentaries is that people end up thinking that the interesting stuff only happens elsewhere.   It doesn’t.  There is just as much interesting natural history in your own back garden and in the stream that flows through your local park, as there is on the African savannah.   We just need to look for it ourselves rather than expect the BBC Natural History Unit to do all the hard work for us.  That’s why I started this blog in 2013, and I hope to continue doing this throughout 2017 too.

Happy New Year.

More diatoms from the roof of the world

tso_moriri_aug16

I have written about the algae in two samples that I brought back from my Indian travels earlier in the year (see “Diatoms from the Valley of Flowers” and “Diatoms from a holy river”) but I also had one other sample packed in the recesses of my suitcase.   This was collected by Heather, as part of her travels from Kashmir to Shimla via Ladakh and the Zanskar Valley, before we met up for our expedition to the Valley of Flowers.  In 2014 and 2015 she collected samples from the littoral zone of Pangong Tso (see “Return to Pangong Tso”); this year, her expedition with Indus Experiences bypassed this lake and, instead, visited another high altitude lake, Tso Moriri .

Tso Moriri is located in Ladakh, in north west India (32° 54’ N, 78° 18’ E), at an altitude of 5200 metres above sea level. It is about 26 kilometres long by 5-6 kilometres wide (between Windermere and Loch Lomond in size, in other words) and a maximum depth of 106 metres.   It is covered in ice between late October and early May.   Like Pangong Tso, the lake is slightly brackish (conductivity: ~1.6 mS cm-1) though this is not quite high enough for the water to have a salty taste.  The lake is a staging post on migration routes for several birds and this, plus the unique fauna of the region, has led to the lake being placed on the list of Ramsar Wetland Sites.

karzok_tso_moririr_aug16

The village of Karzok, and the flat alluvial plain created by the freshwater tributary stream flowing into Tso Moriri, Ladakh, August 2016.

My sample comes from close to the camp site at the village of Karzok, where Heather’s group stayed.  As the photo shows, one of the two major inflows to the lake flows past this village.   The precise location is at the top right of the alluvial fan and, as the photograph below shows, the substrate at this point is mostly gravel and pebbles with just a few larger stones.  As for my other Indian samples, the diatoms were removed from the top surface by vigorous scrubbing with a toothbrush, after which they were treated to a shot of Indian vodka to dull their senses before the long journey back to the UK.

tso_moririri_diatom_samplin

John Macgillivray collecting stones from the littoral zone of Tso Moriri to sample for diatoms, August 2016. 

The diatoms in this sample were sparse but there were enough present to get some idea of the diversity at this particular location.  As is often the case, most of the forms are sufficiently similar to the diatoms I am used to seeing in European samples that it is tempting to use these names, and to infer the ecology from their preferences.   Prominent in the sample (though not particularly abundant) were large valves that were close to Gomphonema gracile or G. hebridense (a. and b.), and there were also at least two species from the Achnanthidium minutissimum complex (d. – g.) and a few valves of Encyonopsis (j.) and girdle bands of Tabellaria flocculosa (not photographed).  Taken together, these suggest low nutrients but, at the same time, lower levels of salts than the reported figures suggest.   Of the other valves present, some resembled Amphora pediculus and there were also Navicula and Nitzschia species, plus a specimen of Sellaphora pupula and a few fragments of a Halamphora species.  Some of these might suggest slightly elevated salinity, but it is an ambiguous signal at best.  Finally, there is a single small specimen of Gomphonema that shares some features (especially the very radiate striae and isolated stigma) with the Gomphonema that I described from Pangong Tso.

tso_mariri_diatoms

Diatoms from Tso Moriri: a., b.: Gomphonema cf gracile / hebridense; c.: Gomphonema species; d. – f.: Achnanthidium sp. (valve views); g.: Achnanthidium sp. (girdle view); h., i.: Amphora cf pediculus; j. Encyonopsis sp.; k., l.: Navicula sp.; m.: Nitzschia sp.; n.: Sellaphora pupula complex.   Scale bar: 10 micrometres (1/100th of a millimetre).

The moral of this story may be that we should not infer too much from a single sample, collected without supporting environmental data, and with valve morphology as the only criterion by which forms are differentiated.   My working hypothesis is that the areas close to the inflow stream may well have fresher water than the main body of the lake, but a proper study would be needed before I would offer that as anything more than an educated guess.

That study is, unfortunately, not an easy task.  The most straightforward overland route into Ladakh is via Kashmir, a route that also allows plenty of opportunity for acclimatisation.   However, the deteriorating political situation in that region complicates travel (the Foreign and Commonwealth Office advise against all but essential trips, which effectively invalidates most travel insurance policies).    Alternatives are to fly to Leh and then take time to acclimatise on arrival, or to travel from Shimla via Manali, which is  longer than the Kashmir routes.  My grumbles about the intrusion of politics into ecology in a recent post (see “This is not a nitrate standard …”) are put into perspective by the very real dangers of travel in many parts of the world.   Samples from both Pangong Tso and Tso Moriri suggest some intriguing questions about biodiversity of ecosystems that have been barely studied until now.   Unfortunately, their mysteries will have to remain unsolved for some time to come.

Reference

Mishra, P.K., Anoop, A., Jehangir, A., Prasad, S., Menzel, P., Schettler, G., Naumann, R., Weise, S., Anderson, N., Yousuf, A.R. & Gaye, B. (2014).  Limnology and modern sedimentation patterns in high altitude Tso Moriri Lake, NW Himalaya – implications for proxy development.  Fundamental and Applied Limnology 185: 329-348.

Tidings of Great Joy …

uk_diatom_flora_homepage

About three years ago I was one of a small group of people who met in the bowels of the National Museum of Wales in Cardiff to discuss the options for producing an online guide to the freshwater diatoms of Britain and Europe.   There were, we reasoned, good guides to most of the rest of the algae found on these islands, and plenty of guides to the diatoms of continental Europe.  There was also an active community of people interested in diatoms for a variety of reasons, both professional and recreational.   There had also been well-intentioned initiatives in the past, the most recent of which was a CD-ROM that I helped to produce for the Environment Agency a few years ago.  I wrote about that sorry saga in “The decline and fall of a CD-ROM”.

There are good reasons why it has not been possible to produce a good guide to diatoms in the past, not least of which has been the shifting sands of diatom taxonomy, which creates instability for anyone who is trying to collate information on the present state of play or, for that matter, to put names on the myriad forms of diatoms that one sees when peering down a microscope.   A more practical reason, over the last few years, has been the absence of anyone with the time and resources to mastermind a project but that situation was about to change, thanks to the National Museum of Wales, who gave their diatom curator Ingrid Jüttner time to work on the project.   They also had experience of developing online taxonomic aids, and a basic “shell” for a website that could be adapted to our needs.   The missing link was funding to allow others with practical or academic interests in diatom taxonomy to travel and meet up to support the project.  That problem was solved thanks to generous support from the British Phycological Society.

uk_diatom_flora_nitzschia

The homepage for the genus Nitzschia in the Diatom Flora of Britain and Ireland.

And so, today, the Freshwater Diatom Flora of Britain and Ireland was launched on the National Museum of Wales website and I encourage you all to have a look.   Comparing the swish tablet-friendly website to our CD-ROM is a salutary experience.   That had to be run from a computer with a CD-ROM drive, which meant that either your microscope had to be close to your desktop or you had a laptop or you were constantly dashing across the laboratory to compare the image on the screen with the specimen under your microscope.  There was, at the time, an edict within the Environment Agency that prohibited desktop computers from laboratories, which further complicated the issue.  Now you can check specimens on an iPad as easily as consult a paper flora.  And that is quite important because, in my experience, there are three levels of biological identification.  First, there is a basic pool of species that you can name from memory, then there are rare and difficult specimens that cannot be identified easily and which require you to consult the literature.   Finally, there is a group of species that fall between these two categories that you recognise but for which you may need a “nudge” to match them to the right name.   For these, an aide mémoire that you can consult easily is invaluable.  I always felt that the Lucid software that drove the CD-ROM was a little too clunky to serve this purpose, but a website accessible via a tablet might approach the functionality of my paper-based identification aids.

The diatom flora has images and descriptions of most freshwater genera, and of the most commonly encountered species.  But there is still a long way to go.   The next couple of years will see us start filling in some of the gaps in order to improve coverage, both in the number of species and the amount of information about each.   At the moment, the focus is on valve morphology, but there is more that could be written about live diatoms and about their ecology, for a start.  But we have made the first steps and, importantly for this modern age, we have burst the old paradigm that regards taxonomic literature as stolid inflexible overviews of the state of the art at a point in time, and emerged blinking into a new era where the medium is flexible enough to accommodate change and evolve as our understanding improves.

uk_diatom_flora_ndissipata

The webpage for Nitzschia dissipata in the Diatom Flora of Britain and Ireland, with the description on the left and images on the right.

This is not a nitrate standard …

Much of my professional life takes place in the collision zone between ecology and bureaucracy.   These make uneasy partners: ecologists like to think of themselves as Lone Rangers riding out to put the world to rights rather than as small cogs in big administrative machines, but the reality is that environmental regulators need both “carrots” and “sticks”, and wielding the latter makes them part of the criminal justice system, with all the responsibilities – and paperwork – that that implies.

I’ve spent quite a lot of time over the past few years working on developing standards for nutrients in freshwaters.   Roughly speaking, I have been helping to define the freshwater equivalent of the 30 miles per hour speed limit.   Speed limits work partly because everyone understands the dangers of driving too fast in urban areas, and partly because we know that there is a good chance of being caught by a speed camera if we drive too fast.   And so it is (or should be) for pollutants: the lower dashed line on the graph of phosphorus in the Ouseburn in the previous post is the “30 mph” limit based on an understanding of how phosphorus interacts with freshwater ecology.   There is a lot I could write about how these values are derived (a subject for another day) but that, in a nutshell, is what we are trying to achieve.

When my students are analysing the data from the Ouseburn, they find standards for ammonia, BOD and phosphorus relatively easily via the UK TAG website but they come to me each year wondering why they cannot find equivalent values for nitrate.  The UK TAG document says “we consider the general understanding of this [nitrogen] to be insufficient at present for it to be used as a basis for setting standards or conditions.”  This was disingenuous in the extreme because I know that DEFRA has been extremely reluctant to set standards for nitrogen as this would focus attention on agricultural pollution which is both much harder to manage and would incur the ire of the farming lobby.   A few years ago, Nigel Willby and I calculated the nitrogen concentrations that would support good status in UK rivers as a by-product of a project to revise phosphorus standards.  We had the data we needed and it struck us that no-one would turn down our “buy one, get one free” initiative.   Not so.  Our figures for nitrogen were quietly excised from our report using the very good argument that it was going to be a hard enough job to argue the case for tighter phosphorus standards without confusing the issue with nitrogen too.  Since then, little has happened, as far as I know, to push nitrogen up the regulatory agenda.

The table below shows these values simply to indicate the values of oxidised nitrogen (which is mostly as nitrate rather than nitrite) that are associated with different levels of ecological status in UK rivers.  They have no regulatory significance, but should give us a rough idea of how much nitrogen is “too much” when we are trying to understand the ecology of a river.

Predicted Total Oxidised Nitrogen (nitrate-N + nitrite-N)  concentrations associated with EQR values modelled for two altitudes (20 and 200 m asl) and four alkalinities (10, 50, 100 and 200 mg L-1 CaCO3).   Boundaries are normalised at 0.8 (high/good), 0.6 (good/moderate), 0.4 (moderate/poor) and 0.2 (poor/bad)); 0.7 and 0.9, therefore, represent conditions at the middle of their respective status classes.

ton_threshold_table

Applying these values to the Ouseburn, a lowland, hard water river, we see that most of the values lie below this threshold except for those from Woolsington, the headwater stretches which are surrounded by agricultural land where there is likely to be extensive use of artificial fertilisers.   The open circles on the right of the graph are values collected by my students each autumn, which may explain why they are lower than the annual mean values that the closed circles to the left represent.  But note, too, the high values in the Airport tributary in the early 1990s.   These occur at about the same time as the high ammonium concentrations that I discussed in “Part of the problem?”.   The ammonium that the airport released into the stream has a nitrogen atom bound to four hydrogen atoms using strong bonds.   Some microorganisms are able to break these bonds and use the energy that is released to drive their own cells.   This is what we see in Airport tributary where the high nitrate is the result of a two-step process that breaks down the ammonium first to nitrite and then to nitrate.

no3n_in_ouseburn

Trends in concentrations of nitrogen as nitrate in the Ouseburn over time.  Woolsington is upstream of the airport, Airport tributary (Abbotswood Burn) receives runoff from Newcastle Airport and Jesmond Dene is about 10 km downstream from the airport.  Closed symbols are annual means of data collected by the National Rivers Authority and Environment Agency; open symbols are means of data collected and analysed by Newcastle University Geography students in October (once also in February) of each yearThe dashed line is the UK environmental standard for reactive phosphorus to support “good ecological status.

The final graph shows concentrations of nitrogen as ammonium and nitrate at the three sites we’ve been examining, along with the (official) standard for nitrogen as ammonium plus my unofficial guide value for healthy nitrate-nitrogen concentrations.  This gives us four quadrants, with bottom left representing situations where both forms of nitrogen are at concentrations that should not significantly impair ecology.   This is the case at the two sites downstream from the airport from the mid-1990s onwards, once ammonia concentrations were under control.

The top right quadrant, by contrast, has just a small number of values from Airport tributary from the early 1990s, when high ammonia was rapidly oxidised to yield high nitrate-nitrogen concentrations too.   A further cluster of sites, mostly from Airport Tributary and Jesmond Dene, also have high ammonium concentrations, although nitrate-nitrogen concentrations are below the threshold.  Finally, at the top left, we have values from Woolsington where concentrations of nitrogen as ammonium are low but nitrate-nitrogen concentrations may be a problem, due to agriculture.

For a river that is less than 20 kilometres from source to mouth, there is a lot happening in the Ouseburn, which makes it ideal for students to become acquainted with the complexities of environmental regulation.   You can read the history of pollution control in the graphs of data too: from intercepting toxic point sources in the 1980s to more general concerns about overflowing storm sewers in the 2000s and, now, more interest in diffuse nutrient pollution from farmland in the headwaters.   That, too, is a good lesson for undergraduates: pollution, itself, is not an unambiguous concept and its definition has evolved as our understanding increases.  One lesson that we can draw from this episode about nitrate standards is that the scientific argument about sensible levels of any pollutant can quickly become obscured by politics and vested interests.  That can never be a good thing.

ouseburn_nitrate_v_ammonium

Relationship between nitrogen as ammonium and as nitrate in the Ouseburn between 1989 and 2016.  The diagonal line has slope = 1 and the horizontal and vertical dashed lines indicate the position of the maximum concentrations that are likely to support good ecological status.   There is no differentiation between Environment Agency data and data collected by Newcastle University students on this graph.

A river is reborn …

I started to tell the story of the Ouseburn in the previous post, but have not yet reached a happy ending.  The Beast that is Newcastle Airport has been transformed, if not by a kiss, then by intelligent regulation, but the river is still far from being beautiful.   The Environment Agency, the Handsome Prince in this particular fairy story (has it ever been described in such terms before?) needs to ride out to find other monsters to slay.

One candidate that my students usually identify in their write-ups is phosphorus, whose concentrations have gradually crept up over the years, as the graph below illustrates.   As in the graphs in my previous posts, I have differentiated between data collected by the Environment Agency and my students.  I have also circled a cluster of points that sit outside the main trend, as a reminder that my students are still learning their craft, and sometimes may make mistakes.   The trend is, nonetheless apparent: the river has had elevated phosphorus concentrations for as long as measurements have been taken, and concentrations are gradually creeping upwards.  The student’s data may exaggerate this slightly, but the trend is definitely there.    Although no sewage works discharge to the stream, there are plenty of storm drains, and there are concerns that domestic “grey water”, and its associated detergent residues, may be entering these rather than the foul sewers.  More recently, a study as part of the Ouseburn River Restoration Project (ORRP) has found that some farmers in the upper part of the catchment are stockpiling farmyard manure on behalf of livery stables and some of the leachate from this may be entering the upper stretches of the river.

phosphorus_in_ouseburn

Trends in concentrations of reactive phosphorus in the Ouseburn over time.  Woolsington is upstream of the airport, Airport tributary (Abbotswood Burn) receives runoff from Newcastle Airport and Jesmond Dene is about 10 km downstream from the airport.  Closed symbols are annual means of data collected by the National Rivers Authority and Environment Agency; open symbols are means of data collected and analysed by Newcastle University Geography students in October (once also in February) of each yearThe lower dashed line is the UK environmental standard for reactive phosphorus to support “good ecological status”; the upper dashed line is the threshold between “moderate” and “poor” status (the threshold between “poor” and “bad” status is at 1.04 mg/L).

In addition to problems such as phosphorus that we can see from our analyses, there are problems that are less obvious because they only happen occasionally, and not necessarily when a sampler is dipping a bottle into the river.  The Pantomime Villain of this story (“He’s behind you …” “oh no he’s not”, “oh yes he is …”) is the overloaded sewerage network and, in particular, the storm sewer overflows which divert foul waste into the river when the sewers are overloaded with surface water from heavy rain.   Even though the graphs in the previous post showed that ammonia and BOD are usually at low levels, there will be short periods when the storm sewers dump raw sewage into the river.  This is a great lesson to my students in why biological monitoring is so necessary: the poor quality of the invertebrate community reflects the state of the river through the whole year, not just the minute or so when the sampler’s bottle is being filled.

A combination of hard impermeable surfaces, the drainage system with its overflows and many artificially-straightened lengths of the river mean that storm water makes its way very quickly to the stream (see “Fieldwork in the rain”).  In extreme cases this can lead to homes and businesses being flooded.   These straightened sections of the river also mean that there is little variation in velocity to create the variation in habitat that would allow a range of organisms to find suitable conditions to thrive.   So another of the objectives of the ORRP is to restore the natural meandering path of the river in the upper stretches as a first step towards creating a more natural river which will, at the same time, slow the flow and reduce the likelihood of flooding downstream.   New property developments such as Newcastle Great Park have been designed with Sustainable Drainage Systems (see “In search of SuDS …”) to create more permeable areas that will soak up rainfall and slow its journey to the river, reducing the size of the flood peaks associated with heavy rainfall.

ouseburn_challenges_oct16

Challenges facing the Ouseburn: left: Newcastle Great Park, one of a number of new or planned housing developments in the upper part of the catchment; right: straightened river channel near Three Mile Bridge beside the Great North Road in Newcastle.

To be honest, there are many grander rivers in the country than the Ouseburn where I would prefer to do my fieldwork.  I feel privileged to be able to visit the River Ehen in the Lake District on a regular basis.   We rightly worry about maintaining fragile ecosystems and rare species in these remote places but the Ouseburn presents equal, if less romantic, challenges.   Most of us are urban, rather than rural dwellers and our most likely interactions with the aquatic world will be with these artificially-straightened extensions to our overloaded sewerage systems.   There is something of Frankenstein’s monster about these rivers: at their worst, in flood, they are our own creations, the result of our own attempts to overrule nature.  So I am very enthusiastic about the work of the ORRP and similar schemes around the country.   These are a small step towards restoring a natural harmony between man and water, and working with, rather than against the powers of nature.  And creating a greener, more pleasant urban milieu in the process.

Part of the problem?

deicer_at_schiphol_dec16

My Newcastle University students are in the final throes of writing up their assignment on the ecological health of the Ouseburn, a small tributary of the Tyne that flows through Newcastle, so I could not resist taking these photographs as my flight from Amsterdam to Bucharest was sprayed with de-icer.  The primary point of the assignment is to make my students better scientists, but I like to also use it to remind them that they can never wholly isolate themselves from the systems that they study.  Most of my students live in the Ouseburn catchment so they are all contributing to the problem that they are simultaneously trying to solve.   And, as I set out this morning on my flight to Amsterdam, I watched de-icer being sprayed and remembered that this, too, may find its way into the Ouseburn.  We are all polluters.  And, these days, the polluter pays …

Newcastle Airport plays a big role in the story of the Ouseburn.  It occupies quite a large site in the upper part of the catchment and has grown over the years from the humble structure which I remember from the 1980s to a major regional airport.  The environmental impact increased as the airport grew in size, particularly in the winter as de-icer drained from the ‘planes, via a small tributary, into the Ouseburn.   The graphs below illustrate this very well.  The original de-icer was a mixture of urea and glycol.  Urea breaks down rapidly to ammonia and, at its peak in 1993, the annual average concentration in this tributary was 35 milligrams – sixty times more than the current target for “good status”.  Over six tonnes of urea could be applied in a single day at this time.

ammonia_in_ouseburn_over_ti

Trends in concentrations of nitrogen as ammonium in the Ouseburn over time.  Woolsington is upstream of the airport, Airport tributary (Abbotswood Burn) receives runoff from Newcastle Airport and Jesmond Dene is about 10 km downstream from the airport.  Closed symbols are annual means of data collected by the National Rivers Authority and Environment Agency; open symbols are means of data collected and analysed by Newcastle University Geography students in October (once also in February) of each yearThe lower dashed line is the UK environmental standard for ammonium-N to support “good ecological status”; the upper dashed line is the threshold between “poor” and “bad” status.

The “yin” of serious pollution in the Ouseburn has, however, been offset by the “yang” of environmental management as the authorities circled around the problems, gradually learning about the river and using regulation and legislation to tackle the issues.   So the graph also shows a rapid decline in ammonia concentrations in the river after 1992 as urea was replaced by a different de-icer, this time based on potassium acetate.  Ammonia concentrations are now generally well within the limits required to support good status, so we should have expected to see organisms characteristic of healthy streams to re-appear.

It has not happened, alas.  As is usually the way, pollution problems are multilayered, like the skins of an onion, and peeling away the first and most obvious problem only reveals further issues lurking below.  In the case of the Ouseburn, the switch from urea to (glycol) created a new problem, as microorganisms in the river were able to use this organic compound as a source of energy, sucking vital oxygen out of the water in the process.  You can see this in the second graph, which shows biological oxygen demand (BOD).  Note how it peaks in the years just after the switch from urea.  Note, too, how values fluctuate (dependent, presumably, on the severity of the winter) and, again, how the peaks exceed the current target for “good status”.   But, on a positive note, more recent values are much lower, as the airport now has better facilities for handling surface water drainage.

bod_in_ouseburn_over_time

Trends in biological oxygen demand (BOD) in the Ouseburn over time.  Details as for the graph showing ammonium-N.

Even after this, however, the river is still in a state that is far from acceptable.  The final graph in this post shows the state of the invertebrates in the Ouseburn (expressed as average score per taxon).  This has gradually crept up over the years but, as can be seen, is still not yet at “good status”.  When we empty the contents of our pond nets into trays and take a look, we see lots of pollution-tolerant water hoglouse (Asellus aquaticus) and freshwater shrimp (Gammarus pulex), bloodworms (Chironomous riparius) and leeches.  There are very few of the caddis flies, stone flies or may flies that we associate with clean water (with the exception of the relatively tolerant Baetis rhodanii).    There are more layers of this onion that still need to be peeled away and I will return to these in a future post.

aspt_in_ouseburn_over_time

I will finish where I began: sitting on an aeroplane that is being sprayed with de-icer.   I’m an ecologist and my particular specialism means that I often need to travel around Europe.  Flying is the only practical way of doing much of this but, in the process, I become part of the problem whilst hoping that I am part of the solution.   I also teach part-time in a Geography department along with colleagues f whose professional calling often makes international travel a necessity.   It makes for some uneasy moral choices.   At worst, we develop a tough veneer that insists that the good we do far outweighs the negative effects of our carbon footprints.   At best … well, perhaps that is not for me to say.   Maybe simply remembering that our travels mean that we are part of the problem should make us approach the systems we study with a little more humility and rather less sanctimoniousness …

References

Turnball, D.A. &Bevan, J.R. (1995).  The impact of airport de-icing on a river: the case of the Ouseburn, Newcastle upon Tyne.  Environmental Pollution 88: 321-332.