I'm not going to apologise for departing, once again, from the theme of this blog. I am appalled that my country has betrayed its younger generation, insulted its European friends, and revealed itself as a stupid, ignorant, self-centred and racist little island.
I can only say two things - first, Seamas O’Reilly, a thirty-year-old Irish freelance write living in London, has written the following, which sums it up perfectly:
“It represents a shameful retreat to a smaller mindset, unshackled from empathy, decency or even just intellectual engagement with complex issues,” he says.
“I am disgusted by this result and the mandate it gives to the most loathsome political elements of this nation. I am saddened by what it says about the British people, what it means for the protection of essential services and workers’ rights, and the truly horrifying implications that the reimposition of military borders could have on the streets of Northern Ireland.”
“[The Leave campaign's] utter contempt for the intelligence of the British public has been evident from day one.”
“In their repeated utterance of statements they knew to be false, in their craven misrepresentation of facts and personal endorsements to their own ends, and in their ugly, disingenuous insistence on focusing on EU immigrants, who they know have repeatedly been proven a net gain to the country and whose numbers are not really reducible by any deal a future British state may seek to strike within the outer EU anyway. This might be why they reverted to simply showing images of huddled non-European people or referring to them as if they were an airborne disease.
“Britain awoke today a poorer, crueller and more dangerous country, and could remain so for decades to come.”
Secondly, the leave campaign was run not only on a fact-free basis, but on a series of lies that appealed to the most basic and venal human instincts - I can only say to my American friends: if this can happen here, watch out in November.
We only have ONE hydrologic system, dammit!
School kids know that (it's in all their textbooks), geologists, geophysicists, geomorphologists, environmental scientists and ecologists, climatologists and meteorologists, resource scientists, most engineers, and a hell of a lot of people on the street know that. It is, however, a fact that seems to have escaped multitudes of politicians, policy-makers, regulators, at least one US presidential candidate, and, of course, commercial enterprises - whether out of profound and inexcusable ignorance or under the influence of vested interests and lobbies is open to question.
But it remains a fact. The entire hydrologic system - rain drops, clouds, springs, creeks, rivers, lakes, snow, ice, run-off, evapotranspiration and groundwater - is interconnected. Mess about with one bit and other parts will be affected - it's complex, but it is one single system.
The title of this post is a quotation from John Wesley Powell, a voice of knowledge and rationality that we could benefit from today - more of that, quite possibly, in a future post. Over 120 years ago, addressing an audience of (booing) vested interests in irrigation at any cost, he said:
When all the rivers are used, when all the creeks in the ravines, when all the brooks, when all the springs are used, when all the reservoirs along the streams are used, when all the canyon waters are taken up, when all the artesian waters are taken up, when all the wells are sunk or dug that can be dug, there is still not sufficient water to irrigate all this arid region. I tell you, gentlemen, you are piling up a heritage of conflict and litigation over water rights, for there is not sufficient water to supply these arid lands.
This occasional series, A Reverence for Rivers, is dedicated to Luna Leopold and perhaps I should add John Wesley Powell. In a the previous episode I quoted from a piece, written over sixty years ago by Leopold and his colleague Harold Thomas:
There are enough examples of streamflow depletion by ground-water development, and of ground-water pollution from wastes released into surface waters, to attest to the close though variable relation between surface water and ground water.
Man has coped with the complexity of water by trying to compartmentalize it. The partition committed by hydrologists—into ground water, soil water, surface water, for instance—is as nothing compared with that which has been promulgated by the legal profession, which has on occasion borrowed from the criminal code to term some waters "fugitive" and others, a "common enemy." The legal classification of water includes "percolating waters," "defined underground streams," "underflow of surface streams," "water-courses." and "diffuse surface waters"; all these waters are actually interrelated and interdependent, yet in many jurisdictions unrelated water rights rest upon this classification.
This jurisdictional and regulatory problem of compartmentalization of water resources contrary to the facts of the way the system works has given rise to many of the profound problems we face today. So I thought it might be helpful to set out some of the facts of the relationships between ground and surface waters and the consequences of ignoring them - bear with me, this may be a summary but it's not going to be short!
First, the interested reader can do no better than to go (as is so often the case) to the USGS. Published nearly 20 years go, Circular 1139 is titled Ground Water And Surface Water: A Single Resource. The synopsis is as follows:
As the Nation's concerns over water resources and the environment increase, the importance of considering ground water and surface water as a single resource has become increasingly evident. Issues related to water supply, water quality, and degradation of aquatic environments are reported on frequently. The interaction of ground water and surface water has been shown to be a significant concern in many of these issues. For example, contaminated aquifers that discharge to streams can result in long-term contamination of surface water; conversely, streams can be a major source of contamination to aquifers. Surface water commonly is hydraulically connected to ground water, but the interactions are difficult to observe and measure and commonly have been ignored in water-management considerations and policies. Many natural processes and human activities affect the interactions of ground water and surface water. The purpose of this report is to present our current understanding of these processes and activities as well as limitations in our knowledge and ability to characterize them.
USGS Circular1376, published in 2012, incorporated material from 1139 and proceed to document in considerable detail Streamflow Depletion by Wells—Understanding and Managing the Effects of Groundwater Pumping on Streamflow. Again, a straightforward summary:
Groundwater is an important source of water for many human needs, including public supply, agriculture, and industry. With the development of any natural resource, however, adverse consequences may be associated with its use. One of the primary concerns related to the development of groundwater resources is the effect of groundwater pumping on streamflow. Groundwater and surface-water systems are connected, and groundwater discharge is often a substantial component of the total flow of a stream. Groundwater pumping reduces the amount of groundwater that flows to streams and, in some cases, can draw streamflow into the underlying groundwater system. Streamflow reductions (or depletions) caused by pumping have become an important water-resource management issue because of the negative impacts that reduced flows can have on aquatic ecosystems, the availability of surface water, and the quality and aesthetic value of streams and rivers.
Both of these publications should be required reading for anyone, anywhere who is even remotely involved in water management and policy-making.
So let's start with a simple and fairly self-explanatory image from the USGS:
Ground-water flow paths vary greatly in length, depth, and travel time from points of recharge
to points of discharge in the groundwater system.
Groundwater, streams and wells all interact and influence water flow, but the rates of that flow vary over several orders of magnitude, from days to millennia. The architecture and physical characteristics (permeability and so on) of the aquifer system are always complex in reality and the distribution of lower permeability (confining) layers will dramatically influence the direction, amount, and rate of flow.
In places where the water table "outcrops" - i.e., intersects with the surface - there will be a spring (as at Havasu Falls, the image at the head of this post, ultimately feeding the Colorado River), a lake or groundwater feeding the flow of a river through its bed and banks. The relationship between the water table and a body of surface water is critical - a stream can be "gaining" flow from groundwater discharge or "losing" it by flow into the water table (depletion):
Groundwater discharge into streams and rivers is commonly the major contribution to their flow which is only augmented by rainfall and surface runoff.
Different segments of a river or stream may be typically gaining or losing and this will vary with the season - if the water table falls, the river may become "disconnected" from the water table, or, in times of flood, the river level may rise higher than the water table and effectively charge storage in its banks until the level falls back to normal.
All these variations occur quite naturally depending on time and place, and the system may be stable for long periods of time. But start pumping groundwater in the vicinity of a river and the system is de-stabilized. As the caption to this next USGS illustration describes, "In a schematic hydrologic setting where ground water discharges to a stream under natural conditions (A), placement of a well pumping at a rate (Q1) near the stream will intercept part of the ground water that would have discharged to the stream (B). If the well is pumped at an even greater rate (Q2), it can intercept additional water that would have discharged to the stream in the vicinity of the well and can draw water from the stream to the well (C)."
To quote again from the USGS:
The first clear articulation of the effects of groundwater pumping on surface water was by the well-known USGS hydrologist C.V. Theis. In a paper published in 1940 entitled "The Source of Water Derived from Wells," Theis pointed out that pumped groundwater initially comes from reductions in aquifer storage. As pumping continues, the effects of groundwater withdrawals can spread to distant connected streams, lakes, and wetlands through decreased rates of discharge from the aquifer to these surface-water systems. In some settings, increased rates of aquifer recharge also occur in response to pumping, including recharge from the connected surface-water features. Associated with this decrease in groundwater discharge to surface waters is an increased rate of aquifer recharge. Pumping-induced increased inflow to and decreased outflow from an aquifer is now called "streamflow depletion" or "capture."
So there is a critical interaction between groundwater and surface water by complex flows that take place over days, centuries and millennia, and wells can cause major changes to that interaction - streamflow can be severely depleted, water tables lowered and aquifer water volume maintenance totally disrupted.
For here is the first of what USGS Circular 1376 intriguingly documents as "common misconceptions." That is:
Misconception 1. Total development of groundwater resources from an aquifer system is “safe” or “sustainable” at rates up to the average rate of recharge.
This is fundamental, because we hear all the time that aquifers are being "mined" as a result of volumes pumped exceeding the recharge rate from rainfall up in the hills - it's really not as simple as this. Because streams and rivers are frequently depleted by losing water to an aquifer, particularly when wells are pumping from that groundwater supply, it is this source that is the dominant way in which an aquifer is recharged, not by water from the hills.
The sources of water to a well are reductions in aquifer storage, increases in the rates of recharge (inflow) to an aquifer, and decreases in the rates of discharge (outflow) from an aquifer. The latter two components are referred to as capture. In many groundwater systems, the primary components of capture are groundwater that would otherwise have discharged to a connected stream or river in the absence of pumping (referred to as captured groundwater discharge) and streamflow drawn into an aquifer because of the pumping (induced infiltration of streamflow)...
Reductions in aquifer storage are the primary source of water to a well during the early stages of pumping. The contribution of water from storage decreases and the contribution from streamflow depletion increases with time as the hydraulic stress caused by pumping expands outward away from the well and reaches one or more areas of the aquifer from which water can be captured. At some point in time, streamflow depletion will be the dominant source of water to the well (that is, more than 50 percent of the discharge from the well) and after an extended period of time may become the only source of water to the well. The time at which streamflow depletion is the only source of water to a well is referred to as the time to full capture.
So, if you choose to define and manage, through regulation and policy, groundwater and surface water as two entirely separate systems, you choose a recipe for disaster - you are more often than not severely double-counting and thereby overestimating your resources and you are not managing the system at all. And yet this is exactly what California, Arizona and, indeed, all the arid States of the Western US (not to mention other States and other countries) have been doing for more than a century. This has been superbly documented in ProPublica's piece, "Less Than Zero: Despite decades of accepted science, California and Arizona are still miscounting their water supplies." That analysis, part of their extensive "Killing the Colorado" series of reports, has also been summarised in the New York Times:
John Bredehoeft, a leading hydrogeologist and former director of the federal government’s Western states water program, bluntly emphasized the importance of basic honesty in counting water.
“If you don’t connect the two, then you don’t understand the system,” he said. “And if you don’t understand the system, I don’t know how in the hell you’re going to make any kind of judgement about how much water you've got to work with.”
Until state officials do, it seems unlikely that there will be any real solution to managing the Southwest’s strained water resources for the future.
But there's another, fundamental, problem - if you can't measure, monitor, document, you can't manage - and the data are essentially not there to measure, monitor and document. For example, California, again from the New York Times:
Although the state has not updated the surveys in the last three decades, the Department of Water Resources recently reported that across most of the state groundwater levels have dropped 50 feet below historical lows, with levels in many areas in the San Joaquin Valley more than 100 feet below previous historic lows.
In California, the state’s water agency has said that the failure to account for how groundwater withdrawals affect the state’s rivers is a major impediment to a true accounting of its resources. In April , authorities reported that less than half of the state’s local water agencies had complied with a 2002 law that made them eligible for state funds only if they set up groundwater management plans and determined if a connection between surface water and groundwater existed. That connection does not exist uniformly and varies depending on local geology. Only 17 percent of the state’s groundwater basins had been examined.
Indeed, California still doesn't require that water pumped from underground be measured at all, much less factored into an overall assessment of total water resources; it’s merely an option under a new law signed last September.
California’s new groundwater legislation does require local water authorities to come up with sustainable groundwater plans, but they don’t have to do that until 2020, and they don’t have to balance their water withdrawals until 2040.
To all intents and purposes, the only way we have to analyse these issues is through computer modelling - very clever and sophisticated, but, at the end of the day it is modelling, not analysis of real-world data. But assembling meaningful real-world data is not easy on a local scale and the time-frame of aquifer behaviour is a long one. Make your way through USGS Circular 1376, and you will find several regional-scale analyses of groundwater/streamflow interaction based on the statistical analysis of data, and the authors document in detail the challenges of field studies, stating that
Statistical studies such as these can be used in general to evaluate the large-scale effects of basinwide pumping on streamflow reductions. They cannot, however, account for the specific effects of pumping at individual wells, nor can they help with understanding how specific management actions might affect future depletion. Such analyses require the use of analytical or numerical models.
So we are largely stuck with modelling. It is, nevertheless, a powerful tool, and several examples are presented in the USGS document. Since we are particularly interested in water and arid lands, here is a very relevant - not to mention fascinating, sobering, and perhaps surprising - example. The situation, that of a hypothetical desert-basin aquifer with a through-flowing river along the east side of the basin, is summarised here (remember that 1 acre-foot of water equals 1233 cubic meters):
There is natural recharge from the west and, under natural conditions, inflow from the river to the aquifer in the north and outflow from the aquifer to the river further downstream. Two wells are drilled into the aquifer, one five miles from the river, the other ten. Each well then pumps at a rate of around 750,000 cubic meters per year, and continues to do so for 50 years when pumping then ceases. The analysis treats each well separately - they are not both pumping at the same time. So let's consider the effects of streamflow of the well closer to the river (but still five miles away). What we are looking at are plots of the resulting increase in flow from the river into the aquifer, decrease in flow into the river from the aquifer and the total changes to river flow (depletion):
Over the period of pumping, the river's flow is decreased by almost 25%, depriving downstream users of water. After pumping stops, the river's flow begins to recover - but note the timescale: the river has still not returned to its natural flow rate after 150 years. And nearly half of the total volume of depletion will occur after pumping stops. The effects of the more distant well are only slightly more modest - but they last much longer and the maximum depletion occurs several years after the well stops pumping.
Now this "hypothetical desert-basin aquifer" may remind you of somewhere - the Ranegras Valley of Arizona, perhaps? Where the Saudi conglomerate, Almarai, are growing alfalfa for export back home? Except that this hypothetical example only covers the effects of one well pumping: Almarai operate 18 wells, each one capable of pumping 4 or 5 times the lonely well in our hypothetical desert valley, and they have received permission to drill 8 more.
Now of course there is no flowing river in the Ranegras Valley, but there is Brouse Wash, ephemeral, yes (although prone to flash flooding), but clearly with water not far below the surface, given the vegetation and the occasional stock pond visible on Google Earth:
So the Brouse River probably flows just below the surface of the wash, and, if it flows at all, will not be doing so much longer as its water supplies the alfalfa.
The Brouse does, I believe, eventually supply modest volumes of water to the Colorado, and, interestingly, while I was researching and preparing this post, Matthew Miller and his colleagues at the USGS published a paper titled "The importance of base flow in sustaining surface water flow in the Upper Colorado River Basin", summarised by Science Daily. The research covered the upper Colorado basin (i.e. upstream from Lee's Ferry and the Grand Canyon) where 90% of the river's flow originates and the work documents that 60% of that flow is provided by groundwater. Subsequently, more than 80% of that groundwater is lost, by evapotranspiration and diversion for irrigation, before it reaches the lower river (where, amongst other problems, Lake Meade has recently been reported to be at its lowest level ever). The abstract for the paper puts it very succinctly:
The Colorado River has been identified as the most overallocated river in the world. Considering predicted future imbalances between water supply and demand and the growing recognition that base flow (a proxy for groundwater discharge to streams) is critical for sustaining flow in streams and rivers, there is a need to develop methods to better quantify present-day base flow across large regions....
Our results indicate that surface waters in the Colorado River Basin are dependent on base flow, and that management approaches that consider groundwater and surface water as a joint resource will be needed to effectively manage current and future water resources in the Basin.
Or, as Matthew Miller himself is quoted as saying, "In light of recent droughts, predicted climate changes and human consumption, there is an urgent need for us all to continue to think of groundwater and surface water as a single resource."
It couldn't have been put better - if you have made it through this post, thank you! And many thanks, as always, to the USGS.
Back in November last year, I described how, very controversially, Arizona is exporting its water in vast quantities to Saudi Arabia, via alfalfa to feed Saudi cattle. In that post I quoted from the work of Elie Elhadj, who has compellingly documented the rape of the Kingdom's groundwater resources:
In 2004, Elie Elhadj of the School of Oriental and African Studies (SOAS), King’s College London published a blunt analysis of the extraordinary history of the destruction of the country’s water supplies. Titled “Camels Don’t Fly, Deserts Don’t Bloom: an Assessment of Saudi Arabia’s Experiment in Desert Agriculture” the report paints a catastrophic picture.
That experiment in desert agriculture is now essentially over, and Saudi Arabia relies almost entirely on imports of crops and cattle feed. In order to satisfy this need, the country's huge food and agriculture business, Almarai, buy farming land elsewhere in the world - including in the Arizona desert. Since I wrote that post, Almarai have added to their assets by buying land on the other side of the Colorado River in south-eastern California. Both California and Arizona are now in their fourth year of severe to exceptional drought.
After I quoted from his work, Elie contacted me and we commenced an email conversation that led to a fascinating and highly enjoyable meeting and discussion. He told me that he was in touch with a group of students at Arizona State University who were making a short video on the issues of exporting water to Saudi Arabia, and that video is now on line - it's extremely well done and worth watching:
There is an interesting cast of characters (in addition to Elie Elhadj himself): local residents who have seen the water levels in their wells drop 50 feet in four years, a lawyer for Almarai who, when talking about any link between water problems and agriculture, cheerfully states that "I don't think that's the case", local people agreeing that some form of regulation is needed as long as their water usage is not regulated, and Kathleen Ferris of the Morrison Institute for Public Policy at Arizona State, who comments that "It's almost impossible to manage groundwater without some kind of regulation." Such a statement may seem blindingly obvious, but the fact is that, in La Paz County Arizona there are no regulations whatsoever - anyone can arrive, drill as many wells as they want, and deplete the groundwater resources to whatever extent pleases them.
This is madness. Consider the likely reaction of our old friend the alien scientist, flitting around the earth on a resource analysis mission and observing this scene:
"Wait a minute. There's the huge canal that they built to take water from the dwindling and over-exploited flow of the Colorado River, specifically to supply the city of Phoenix where groundwater supplies had been drastically depleted, and, right next to it are fields of water-sucking alfalfa grown to be exported as feed for Saudi cattle - this is no way to run a planet."
Yes, this may be madness for Arizona and California, but it's only part of a global-scale pattern of unsustainable insanity - and we should not be quick to judge Arizona. In a recent issue of the New Scientist, there was an interview with Arjen Hoekstra, a professor of water management at the University of Twente, in the Netherlands, and founder of the Water Footprint Network. Hoekstra and his colleagues have developed a careful and extensive method of measuring water footprints, expressed as per capita usage country-by-country, and allocating the proportion of blue, green and gray water:
The WF is a measure of humans’ appropriation of freshwater resources and has three components: blue, green, and gray. The blue WF refers to consumption of blue water resources (surface and ground water), whereby consumption refers to the volume of water that evaporates or is incorporated into a product. The blue WF is thus often smaller than the water withdrawal, because generally part of a water withdrawal returns to the ground or surface water. The green WF is the volume of green water (rainwater) consumed, which is particularly relevant in crop production. The gray WF is an indicator of the degree of freshwater pollution and is defined as the volume of freshwater that is required to assimilate the load of pollutants based on existing ambient water quality standards.
The title of the interview is "We can avoid a water crisis, but the fix will be hard to swallow" and, when asked "How is the UK doing in terms of water use?", he replied:
Because it imports so many goods, three-quarters of the UK’s water consumption is actually outside of its borders. And about half of that usage is not sustainable. For example, the UK imports rice and olives from southern Spain and sugarcane from Pakistan, regions where water is overexploited. This means groundwater levels are declining and rivers dwindling or drying up. That’s bad news for the exporting countries and for the UK, because these food sources will ultimately fail.
In terms of the broader region, Europe is the biggest net importer of water-intensive commodities in the world, much of it from water-scarce regions. In fact 40 per cent of Europe’s water footprint is outside the continent. A large part of that is unsustainable.
So let's not get too smug about Arizona, but, rather, worry about the large-scale problem. In terms of water footprint, domestic use is only a small part of the total - in Europe, the average consumer’s domestic use is typically only 1 to 2 per cent of their total water footprint. It's agriculture, what food we demand, where we choose to get it from, and how much we're prepared to pay for it that is the overwhelming factor. As Hoekstra comments
All food has a big water footprint, because agriculture is the largest water consumer. Grains generally have a water footprint in the order of 1000 litres per kilogram. Beef is, on average, 15,000 litres per kilogram. Both are big numbers but you can see that meat is in a league of its own. So your diet, and particularly how many animal products you eat, has a big impact on your personal water footprint.
Take a look at that link - it's at the same time fascinating and alarming.
But it's the blue water footprint that is of particular interest here and, fortunately, in one of his publications, Hoekstra breaks down specifically the blue water footprint by country and internal versus external, i.e., indigenous versus imported. Take a look at the whole, intriguing, paper where the graph appears in the supplementary materials. I have cropped the complete graph to start with the UK on the left and highlighted the UK, China, the US, Spain, Pakistan, and Saudi Arabia - plus the world average in green.
Blue water footprint of national consumption for countries with a population larger than 5 million, shown by internal and external component (cubic meter per year per capita,1996–2005)
Take a good look at this graph and think through the overwhelming complexity of the issues. Countries whose footprint is relatively small may be dominantly importing other peoples' water - take the UK, for example. Countries whose footprint is large may be mainly consuming their own water but depleting and exporting it (see the US for example). There's an incredible set of questions and issues embedded in this graph, and add to this, overlay, Hoekstra's illustration of just the major global water flows:
Virtual water balance per country and direction of gross virtual water flows related to trade in agricultural and industrial products over the period 1996–2005. Only the biggest gross flows (>15 Gm3∕y) are shown.
By this measure, the US is not a net water importer. But then how much of its own water does it export? And then look at Europe.
I'm going to leave it there - you could write a book about it. In fact, Hoekstra has. To say that this is a thorny problem is a massive understatement - arguably has the makings of shorter-term crisis than climate change. What can we do about it? Well, in Hoekstra's words from the New Scientist interview, the fix can be hard to swallow:
We in northern Europe should realise that we are actually quite well off with water, and ask why we import water-intensive goods from water-scarce areas. It doesn’t make sense that we produce so little of our own food.
Isn’t this an inevitable effect of global markets?
Yes. We lose our own agriculture because elsewhere you have free water, cheap land, cheap labour. But it is not truly cheap; it is at the expense of the people over there, their land and their water. And in the long run, our own food supply is at risk. We need to change the rules of the market by discriminating in favour of sustainable production. It is a global challenge for agriculture, power generation, trade and economics, which we must work together to address. It’s a big deal, and it will only get bigger.
Our societies need to think long and hard about this - and read Hoekstra's latest paper: "Four billion people facing severe water scarcity."
Described as one of the last great enigmas or mysteries, the so-called fairy circles of the arid lands of Namibia remain to be explained. Theories abound, and the fairies have stimulated "lively" academic debate, if not discord. The circles occur in their millions in a band of dry grassland stretching 1800 kilometres south from the Angolan border - but it's now clear that Australia has its own fairies.
In both places, countless circles dot the landscape like a pox of some kind:
Fairy circles in the Marienfluss Valley of Namibia.
(Google Earth image, ~ 650m across)
The circles are rimmed with (more or less) growing grass, vary in size up to several metres across and would seem to grow. Within them their is nothing but bare earth. Explanations include ostriches, rolling zebras, underground gas (or dragons' breath), footsteps of the gods, microbial activity, poisonous plants, termites, and the competition for scarce water. It's the last two that form the main rival hypotheses. As far as biologist Norbert Juergens of the University of Hamburg is concerned, it's termites. But Stephan Getzin of the Helmholtz Centre for Environmental Research (UFZ) in Leipzig disagrees - for him and his colleagues, fairy circles result from the way plants organize themselves in response to water shortage. Here's the abstract of this group's paper:
Vegetation gap patterns in arid grasslands, such as the “fairy circles” of Namibia, are one of nature’s greatest mysteries and subject to a lively debate on their origin. They are characterized by small-scale hexagonal ordering of circular bare-soil gaps that persists uniformly in the landscape scale to form a homogeneous distribution. Pattern-formation theory predicts that such highly ordered gap patterns should be found also in other water-limited systems across the globe, even if the mechanisms of their formation are different. Here we report that so far unknown fairy circles with the same spatial structure exist 10,000 km away from Namibia in the remote outback of Australia. Combining fieldwork, remote sensing, spatial pattern analysis, and process-based mathematical modeling, we demonstrate that these patterns emerge by self-organization, with no correlation with termite activity; the driving mechanism is a positive biomass–water feedback associated with water runoff and biomass-dependent infiltration rates. The remarkable match between the patterns of Australian and Namibian fairy circles and model results indicate that both patterns emerge from a nonuniform stationary instability, supporting a central universality principle of pattern-formation theory. Applied to the context of dryland vegetation, this principle predicts that different systems that go through the same instability type will show similar vegetation patterns even if the feedback mechanisms and resulting soil–water distributions are different, as we indeed found by comparing the Australian and the Namibian fairy-circle ecosystems. These results suggest that biomass–water feedbacks and resultant vegetation gap patterns are likely more common in remote drylands than is currently known.
Note "no correlation with termite activity."
The patterns are fascinatingly regular and there has been a suggestion that the geometry of organisation is, bizarrely, directly equivalent to that of skin cells. Robert Sinclair, who heads the Mathematical Biology Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) in Japan, and his collaborator, Haozhe Zhang, were the first to identify this strange analogy.
Both the majority of fairy circles and majority of cells have six neighbors. But the similarity gets even more specific -- the percentage of fairy circles with four, five, six, seven, eight and nine neighbors is essentially the same as the skin cells. "I didn't expect it to be so close," Sinclair said. "We spent a lot of time checking because it really looked too close to believe."
... The researchers suspect the patterns might be similar because both skin cells and fairy circles are fighting for space. If true, scientists might one day be able to glean information about systems just by analyzing patterns. For example, they could search for signs of life on other planets or moons, where images are usually the only data initially available.
Finding such a pattern could also benefit ecology and biology in general. Understanding processes on one scale could illuminate what is happening at the other end of the spectrum. "Otherwise, we need a whole new theory for each type of system we study, and may miss general principles, or, as some say, not see the forest for the trees," Sinclair said.
Self-organising systems and patterns are widespread and intriguing - I can't help but think of so-called "patterned ground," the permafrost polygons of the periglacial regions, the patterns on Mars (and now on Pluto), and various strange behaviours of granular materials...
Oh, and in aid of conservation in the NamibRand Nature Reserve, you can, if you wish, adopt a fairy circle.
[Image at the head of this post credit, Stephan Getzin. The BBC has a very good piece summarising this mysterious phenomenon]
"Epic" "intimate" "brutal" "riveting" "spellbinding" "spectacular." The adjectives come tumbling out of the reviews - but please see this movie for yourself. Described as an "Arabic Western" and a "coming of age story," I suspect that this is one of those rare films that stimulates a unique reaction in every viewer.
Directed by British-born Jordanian Naji Abu Nowar, the story is set during the First World War at the time of the Arab Revolt, and, given that it was filmed in and around Wadi Rum, the instinctive reaction is "ah, Lawrence of Arabia." But, other than the location and the historical context, these films have absolutely nothing in common. "Theeb" is filmed entirely with Bedouin people for whom this is their first experience of acting; it is their story and, most of all, it is the story of a young Bedouin boy caught up in a strange and frightening journey and through whose eyes we perceive the events.
Theeb ("wolf") is played by Jacir Eid Al-Hwietat. Abu Nowar has commented that he "never actually liked [Jacir] as an actor as he was so shy and quiet and I never considered him, but he has this crazy thing that when you put him on camera he a different person. Immediately it became obvious. And so he was the first person we cast and we never looked back or at anyone else." It is indeed not only this kid's extraordinary performance but the kid himself that makes this movie, and, together with Abu Nowar's unique and sensitive directing skills, creates an intangible grip on the viewer. And this grip lasts for the entire film - at the end I could not fathom how one hundred minutes had just gone by.
Watch the trailer:
In a fascinating interview, Abu Nowar comments that:
The time in which the film is set is the single most important period in Middle-Eastern history. That’s when the end of a 400 year empire came to be and radical redrawing of the map which we are still suffering from today. With all the issues going on in Iraq, Syria, with the Kurds and the Turks, Israel and Palestine, Saudi Arabia and the Yemen. All of these issues we hear about today are a direct result from that single moment in history. So, it was such a crucial moment and such an existential crisis for the region and I like the mirror of the character going through a similar sort of crisis.
For myself I wanted to make something that felt authentic to the Bedouin. And so I tried to listen to them as much as possible and incorporated their feelings and thoughts as much as I could. All of it was just exciting for me. I love their poetry. I love their stories and so it was why it comes about in that way. In no way was I trying to enforce a cinematic understanding of storytelling onto subject matter, it is really the subject matter informing it.
And I think that is why is has that feel because it is really genuine. Sometimes the best thing you can do as a director is to step out of the way and not put you two cents in and let people do their thing. I do that and I like getting surprised by what they come up with. That’s the enjoyment of it. There were things all along the way, for example the sound design adding little tiny moments here and there that you pick up and generally just member of the team surprising you. It was a lot of fun.
"Theeb" premiered at the 71st Venice International Film Festival on 4 September 2014, where Abu Nowar won the award for Best Director. It was nominated for the Best Foreign Language Film at the 88th Academy Awards, making it the first Jordanian nomination ever.
It just doesn't stop, and the scale of the damage to communities and the environment is staggering.
NASA recently released the pair of images, above, showing changes to the sediment system of Poyang Lake and its rivers. The lake, these days much diminished in size, was once the largest freshwater lake in China, its water feeding into the Yangtze and providing an important haven for migrating birds. But when, in 2000, China shut down sand mining along the middle and lower Yangtze, the activity, legal and illegal, simply moved to Ponyang. The image on the left was acquired in 1995, the one on the right in 2013. The scale of devastation is obvious - try the "image comparison" feature for drama.
The text accompanying the images describes the problem here (and elsewhere) in depressing detail:
When you see the vast expanses of sand in the Sahara and other major deserts, it is hard to comprehend how sand could ever be a resource in short supply. Yet for certain types, the supply of sand is indeed short.
For the construction industry, river and lake sand is more desirable than desert and ocean sand. To produce mortar for cement, concrete, and other building materials, the angular sand particles found in rivers and lakes are most useful. Making a strong mortar with the particles found in deserts—which are rounded by winds—is more challenging because the sand does not bind together as well. Likewise, ocean sand is mixed with salt, which can cause metals to corrode. Washing this marine sand can be time-consuming and expensive.
Over the past few decades, the global demand for construction sand has boomed, especially in Asia due to rapidurbanization. In China alone, the demand for cement has increased 438 percent over the past two decades,according to the United Nations Environmental Program.
In 2000, dredging and other sand mining become so intensive along the Yangtze River that Chinese authoritiesbanned the activity along the lower and middle reaches of the river. This drove many sand mining operators to Poyang Lake, a large body of water that flows into the Yangtze about 600 kilometers (400 miles) upstream ofShanghai.
This pair of false-color images captured by Landsat satellites shows the impact of sand mining on the northern reaches of Poyang Lake. The top image was acquired by the Thematic Mapper on Landsat 5 on December 7, 1995; the second image shows the same area as observed by Landsat 8’s Operational Land Imager on December 24, 2013. Water levels vary throughout the year at Poyang Lake, with the lowest levels occurring in winter.
By contrasting the two images, we can see dramatic changes in the outlet channel that connects Poyang Lake to the Yangtze river. Sand removal and dredging have deepened and widened the channel significantly. These activities also have left the remaining sandbars and shores with an irregular, serrated appearance. Turn on the comparison tool to see the changes.
As part of an effort to assess the scale of the sand mining and its environmental impacts, a group of researchers analyzed data collected by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor on NASA’s Terra satellite. Using infrared data collected by ASTER in 2005, the researchers found that the lake was producing up to 236 million cubic meters of sand per year—about 9 percent of the total produced by China. The researchers estimated that the volume of sand removed was probably enough to make Poyang Lake the largest sand mining operation in the world.
“Sand mining has compromised the ecological integrity of the lake by contributing to less predictable seasonal water fluctuations and to a series of recent low water events,” said James Burnham, an ecologist with the University of Wisconsin and the International Crane Foundation. Burnhan has conducted field research on wintering waterbirds at Poyang Lake. “This is a lake that hosts 98 percent of the endangered Siberian Cranes and Oriental White Storks, as well as a significant number of over a dozen other endangered waterbirds in the winter.”
Google "sand" and news and, among the entertaining images of sand sculptures and odd reports such as the discovery of hundreds of kilos of marijuana buried in the dunes of South Padre Island, Texas, you will find, every day, endless reports of the issues of sand mining around the world. A sampling:
Vietnam, Nepal, India (endless problems, mafias, crime), Cambodia, Singapore and Malaysia, the list goes on. The issues raised by the documentary, Sand Wars, have also been taken up by The Smithsonian, the United Nations, Wired, and Coastal Care. Numerous TV and radio programmes have covered the topic. And yet so few people are aware of it, and it just goes on and on.
I spent twenty years of my life living and working in the US.
My wife is American. My kids were born in Detroit and Dallas (and my daughter currently works in non-profit health care in New York). My first visit was for a year when I was six years old – my father was one of the pioneers in developing American Studies programmes in British universities where, at the time, literature stopped in the nineteenth century. I first heard a Bob Dylan record sitting in a café in Berkeley in 1963. I spent a year at graduate school in the US during the turmoil of the late 1960s – US graduate programmes had more to offer than UK universities and, anyway, I loved the US. Later, I taught geology at two different US universities, working with (and learning from) terrific graduate students whose dedication led to their obtaining masters’ degrees while holding down jobs. I can only name a couple of states that I haven’t spent any time in. I have worked in five different US cities. To say that some of my best friends are American is correct, and this doesn’t include the countless people I admire and respect.
Whenever, in the early days, I returned to the UK, I found that I had to spend significant time defending the US against the knee-jerk Americophobia of the Brits – but I did so with sincerity and enthusiasm.
Today, however much I would want to, I just can’t do that anymore, and that saddens me – deeply. It’s no longer easy to recognise the country that, for decades and despite all its faults, I enjoyed and admired.
What the hell is happening to the US? Why do I find myself the victim of a masochistic obsession to constantly check the news, follow up on the latest outrageous events in the dominant half of the presidential campaign – and, more often than not, find myself shouting at my computer? In November 2008, there were, quite literally, tears in my eyes as I watched Obama’s victory speech. Today, there are again tears in my eyes – not, this time, of optimism, but rather of bewilderment, disbelief, and something close to horror.
When did the US become a country in which hatred dominates the news, and, of course, social media? When did the US become a country in which most of the so-called political debate, highjacked by the leaders of one deranged party, takes place in the gutter, with rhetoric and vocabulary at the level of a fourth-grader? When did the US become one of the world leaders in inequality? When did home eviction become big business? When did the US become a country that poisons the water of its citizens and yet no-one is accountable? When did the “land of the free,” whose greatness was founded on immigration and diversity, embrace the rhetoric of xenophobia?
Why do I see on social media posts of which Goebbels would have been proud?
When did a complete disregard for facts and evidence become a hallmark of so many American politicians? When did science - when the US has some of the world’s finest institutions - become something to denigrate? And when were humanity and engagement with the rest of the world dropped from the agenda of so many representatives of the home of democracy?
Now please don’t get me wrong. By my standards, the UK has little to be proud of when our government, declaring itself the home of “compassionate conservatism,” presides over rampant inequality, undermines our health system, callously penalises the disabled, spies on its citizens (sorry, “subjects”), attempts to muzzle our scientists through lobbying legislation, and refuses to take in desperate refugees. And yes, we have right-wing lunatics of our own.
No, I’m not claiming any moral high ground – indeed, I’m not sure where to find such a place. I simply can’t defend many of my country’s actions or the way in which our politics is evolving. But I find it impossible to explain or defend what’s going on the US today – and I am deeply saddened.
[I sincerely hope that I have not offended any of my American readers. I shall return to the arenaceous and the arid shortly.]
The desert has its own palette, distinctive and at the same time subtle yet dramatic. There are many factors at work creating the patterns and hues of arid lands - obviously the kind of sand, the kind of rock, the vegetation, minerals and salts, desert varnish - but there are also artists at work that we can't see and barely understand: microbial communities.
We can see the mosses and the lichens, but the vast ecosystem of bacteria and fungi operates essentially invisibly; we are only beginning to scratch the surface of the desert to reveal the ubiquity and importance of microbial life in environments we often describe as "lifeless." These are communities labelled "cryptic" by biologists, a useful term disguising the fact that they are something we really don't understand very well. I found this definition helpful, from a piece in Nature a few years ago titled "Body doubles" by Alberto G. Sáez and Encarnación Lozano:
Have you ever approached someone whom you thought you knew, talked to him with familiarity, only to find out later that he was a complete stranger, albeit remarkably similar in appearance to the person you had in mind, such as a twin brother? Well, taxonomists are similarly puzzled when they come across two or more groups of organisms that are morphologically indistinguishable from each other, yet found to belong to different evolutionary lineages. That is, when they discover a set of cryptic species.
The microscopic cryptic communities of arid lands form the well-known "desert" or "cryptobiotic" crusts that we now realise play key roles in the ecosystem, cycling carbon dioxide and nitrogen, providing resources for plant life, controlling drainage and the hydrologic behaviour of the soil, and reducing erosion - and hence, atmospheric dust.
Among the leading researchers shedding light on these cryptic communities is Ferran Garcia-Pichel at Arizona State University's School of Life Sciences. For example, in 2013, togather with international colleagues, he published a paper titled "Temperature Drives the Continental-Scale Distribution of Key Microbes in Topsoil Communities." Science summarises the work as follows:
Soil microorganisms make up a substantial fraction of global biomass, turning over carbon and other key nutrients on a massive scale. Although the soil protects them somewhat from daily temperature fluxes, the distribution of these communities will likely respond to gradual climate change. ... [We] surveyed bacterial diversity across a range of North American desert soils, or biocrusts—ecosystems in which photosynthetic bacteria determine soil fertility and control physical soil properties such as erodability and water retention. Most of the sites were dominated by one of two cyanobacterial species, but their relative proportions were controlled largely by factors related to temperature. Laboratory enrichment cultures of the two species at different temperatures also showed temperature as a primary determining factor of bacterial diversity. It is unknown if temperature will affect the distribution of other soil microorganisms, but the marked shifts of these two keystone bacterial species suggest further change is in store for these delicate ecosystems.
The work, only available behind the Science paywall, was helpfully reported by Live Science. The two dominant "keystone" bacterial species are Microcoleus vaginatus and M. steenstrupii, the former preferring cooler conditions whereas the latter likes things hot. As temperatures vary, things become competitive and warming conditions result in the mysterious steenstrupii taking over. Now, because these communities are microscopic and cryptic, we can only measure such effects - and detect which organisms are in the soil - through sophisticated DNA analysis. It is further results of this kind of painstaking and careful work that Garcia-Pichel and his colleagues have just published in Nature. With Estelle Couradeau, also at Arizona State, as the lead author, the paper describes - startlingly - how "Bacteria increase arid-land soil surface temperature through the production of sunscreens." Microcoleus vaginatus and M. steenstrupii are far from alone, and, amongst their companions are tribes of cyanobacteria such as the hundreds of species belonging to the genera Scytonema and Tolypothrix. These little critters dislike the sun and apply a biosynthetic sunscreen, scytonemin, an alkaloid pigment that strongly absorbs solar radiation and dissipates this energy as heat. This sunscreen can be seen as patches of darker colour covering areas of desert crust, as in this photo by Garcia-Pichel from the recent report on Science Daily.
This pigmentation may protect some members of the bacterial community, but it can locally warm up the surface by as much as 10 degrees C (18 degrees F). This has a dramatic effect on the health of the cool-loving Microcoleus vaginatus, but is welcomed by M. steenstrupii, who come to dominate as the sunscreen develops, at the expense of vaginatus. As Garcia-Pichel comments:
... we can show that the darkening of the crust brings about important modifications in the soil microbiome, the community of microorganisms in the soil, allowing warm-loving types to do better. This warming effect is likely to speed up soil chemical and biological reactions, and can make a big difference between being frozen or not when it gets cold... On the other hand, it may put local organisms at increased risk when it is already quite hot.
And this has to be happening on a global scale. As Estelle Coradeau suggests, "Because globally they cover some 20 percent of Earth's continents, biocrusts, their microbes and sunscreens must be important players in global heat budgets. We estimate that there must be some 15 million metric tons of this one microbial sunscreen compound...warming desert soils worldwide."
But because we have only a poor understanding of what exactly these desert crusts are and how they work, their roles in local ecology and global systems are impossible to define. It is only through the meticulous work of Ferran Garcia-Pichel and his team, together with others such as Jayne Belnap of the USGS in Moab, Utah, that we can begin to unravel the extraordinary nature and contributions of these long-ignored microbial desert communities. As Belnap has commented:
These are the only game in town to prevent dust storms and erosion, so they're really, really critical parts of this ecosystem. Yet we've never asked the question, 'who's really in there, and what's going to happen there as things shift?'
and, as reported in a piece on Belnap in High Country News, the palette and patterns of our arid lands owe much to an invisible living world:
She also remains convinced that the dark shadows on the desert are the true — and fragile — foundation of the Colorado Plateau. "Whenever we pull on the thread of what makes the system tick," she says, "we end up with soil crusts on the other end."