From the INSTITUT NATIONAL DE LA RECHERCHE SCIENTIFIQUE – INRS
Urbanization: The historical cause of low oxygen conditions in European lakes
The secrets lake sediments have to share
A new study shows that hypoxia, i.e. low oxygen conditions, in European lakes started in 1850, becoming more widespread after 1900, long before the use of chemical fertilizers and climate change. A Canadian and European research team has identified urban expansion as the reason for the low amounts of bioavailable oxygen in numerous European lakes in past centuries. Published in Proceedings of the National Academy of Sciences, the findings of this study directed by postdoctoral fellow Jean-Philippe Jenny and Professor Pierre Francus of INRS suggest that increased waste water pollution at the turn of the 20th century boosted the lakes’ biological productivity, which in turn led to a rise in oxygen consumption.
The researchers analyzed information such as climate, land use, and lake sediment data from more than 1,500 European watersheds. For the first time, they compared reconstructions of land occupancy and land use dynamics on a continental scale to their own data of oxygen depletion over the past 300 years. This allowed them to identify urban waste, primarily phosphorus, as the factor responsible for triggering hypoxia at the bottom of lakes starting at the beginning of the 20th century.
“Accurately identifying the source of the nutrient responsible for oxygen depletion was a real challenge because of the variations in environmental stress factors throughout the region and their interactions, as well as the reliability of long term data,” explains Professor Francus of the INRS Centre Eau Terre Environnement.
“Point and diffuse sources have always contributed to nutrient supplies in lakes, but at intensities that vary in time and space,” adds Jean-Philippe Jenny, now affiliated with the Max Planck Institute for Biogeochemistry in Germany. “Our results show that urban point sources of phosphorus are the dominant cause of eutrophication of European lakes during the Anthropocene.”
The researchers recognize, however, that during recent decades, diffuse sources have gradually become the major cause of fresh water eutrophication in developed countries with the increase in the use of chemical fertilizers and the elimination of point sources due to the installation of waste treatment plants.
“Despite the many cleanup initiatives in the 1980s, the deepest layers in the lakes we studied still are not being reoxygenated and the hypoxia persists. This illustrates the importance of studying historical land use and the need to put long-term strategies in place to maintain and restore water quality in lakes,” say the study’s authors.
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About the publication
Published in Proceedings of the National Academy of Sciences, the article “Urban point sources of nutrients were the leading cause for the historical spread of hypoxia across European lakes” is the result of an international research partnership involving researchers from Quebec, other Canadian provinces, Germany, Finland, and France. The principal author is Jean-Philippe Jenny of the INRS Centre Eau Terre Environnement. This study was produced by the Varve Working Group under the International Geosphere-Biosphere Programme, IGBP-PAGES (Past Global Changes). It received funding from the National Sciences and Engineering Research Council of Canada, the Canada Research Chair in Fresh Water Ecology and Global Change, Fonds de recherche du Québec – Nature et technologies, and the Academy of Finland. DOI: pnas.1605480113
With no mention of “climate change” anywhere, how did this ever get through? It’s a miracle.
Another jump to conclusion without adequate data.
Storm water borne organic material including grass clippings, general refuse, road grime, dog droppings and even seagull or duck droppings were always the main culprits for low oxygen in a large fresh water ornamental lake I had a role in managing. Although fertilisers were always present in the urban stormwater runoff, it was significantly less than the organic pollution. Bacteria counts would rise and fall with water temperature and organic load, as well as algal levels. The pathogenic bacteria was even DNA tested as to source. Bottom line was that the lake generally self managed its levels of these organisms with our only intervention being to post advisories for public awareness and request the water police to drive their power rescue boats around the small bays that would stagnate under low summer flow conditions. As power boats were otherwise banned they loved having this excuse for a bit of a lark but it mechanically aerated the surface waters down to propeller depth. Otherwise oxygen levels were always sufficient to support a large fish population. Unfortunately many of them were the non native European Carp.
This is one place where there is a use for windmills, water aeration. It seems to be the answer for eutrophication and is used in many places, including the Thames estuary.
Hypoxic zones occur naturally…..but in all the lakes they studied….it’s all man’s fault
hogwash
This is not new. In Hyderabad environmental groups are fighting with the groups organising festival at mass scale and immersing idols [thousands] decorated with chemical colours and made of plaster of paris material — during Ganesh & Durgamata festivals in each year. They filed cases in the court also. But government itself encouraging as the cost running in to thousands of crores of rupees. In 2009 in Hussainsagar Lake at the heart of the city BOD was 50.27 before Ganesh idols immersion and after immersion it was 145.35 [they are respectively for COD are 141.5 and 580.2]. I published several articles in local daily newspapers and also included in scientific articles — including book]. This lake was built in 1562 and Hyderabad created in 1591.
Dr. S. Jeevananda Reddy
Hello, while I do not believe in Gods, of any sort, I recall the bit in the Bible which says, “As ye sow, so shall ye reap”. So true.
Michael Elliott
What happened in the late 60s and early 70s?
Let me see… Cut out CO2 and that will help increase the Oxygen Cycle, said the Mad Hatter.
Alice in Wonderland: And if not, there must be more than one way to skin a cat, If you’ll… pardon the expression.
Cheshire Cat: Most unpleasant metaphor. Please avoid it in the future.
Good to see objective scientific inquiry is alive and well
I WAS there and I don’t remember any of it!
It seems highly likely the human activity was the principle reason for water quality degradation.
In London as populations grew the River Thames became a stinking polluted sewer which could not support fish – until Joseph Bazalgette built the first extensive city sewer system in the 1860’s.
The Ironbridge Gorge on the river Severn was the birthplace of the industrial revolution in the late 18th century. With little regard for health and safety or control of hazardous substances the river turned into a seriously polluted open sewer.
With improved regulation and practices in most of the developed world the threat from abuse by homo sapiens has changed – but there is no doubt that as a species we will have materially impacted on inland water quality.
Yup, indoor plumbing was invented before water treatment.
As i understand it the bottom of the Black Sea is quite devoid of oxygen and it has been around for eons.
The primary cause of hypoxia has been sewage for centuries now. Seriously. Remember the “Great Stink” of London? This was why we invented activated sludge treatment for sewage. They teach this in introduction to wastewater, the minimum needed to get a class D license for a job at a water treatment plant.
Quite literally, this study, performed by multiple people with doctorates, came to a conclusion already known by every low level grunt who takes care of your poop.
“…during the Anthropocene.”
That did it for me. Lost me on the spot.
But with the correct scientific paradigm, you can always convict the anthropogenic source. Every time.
A recent post noted that scrubbing of coal power flue gases improved the air quality by reducing particulate matter below ambient levels in the atmosphere reminded me of sewage treatment work I did 40 years ago where the treated sewage effluent discharge was improving the quality of the receiving waters. My company actually received several commendations from local governments for improving the environment. The paper should not be a surprise to anyone who has worked in the water and waste water industry.
We learned a long time ago that we were causing early eutrophication of water bodies and how to remedy it. Sadly, we still don’t do as much as we could do as a species. The extreme pollution of the Black Sea perhaps being a good example. The clean up of the Thames and other water bodies being a great example of the good humans can do.
Sadly, we could do much more for humanity and the environment if we weren’t wasting so much time and money on “Global Warming” …IMHO
One of the standard measures of how much organic material is entering a river, stream, pond, lake, or other water resource is “Biological Oxygen Demand”.
A small contribution to BOD is animal waste of which human waste is a part, but most of it is simply decaying biomass.
It’s seasonal, and proportionate to the availability of deciduous plant material, which has thrived and proliferated since the end of the Little Ice Age.
Where to start on a crock of garbage like this…its obvious they’ve decided that P is the problem well before they did any (ha ha) ‘research’
How does P remove oxygen from water?
Where rivers & lakes have cleaned up since 1850 is it because sewage treatment has removed P from the sewage?
Or K or N for that matter?
Do sewage works now remove those nutrients from waste water?
OK you say, P fertilises the bacteria but, don’t they need something to eat – some organic matter for example?
But wait, don’t sewage works oxidise the organics before letting the treated stuff go, with all the N, P and K still in the water? Sewage treatment treats the organic fraction.
And where does all the organics come from? Could it not just maybe be a whole load of people eating a shed-loads of nutrient-free sh1t food = carbohydrate. If you eat a lot of sh1t, you produce a lot of sh1t. Rocket science it ain’t. And how many times are we lectured that eating more plant material will solve AGW. Yes, eating sh1t food turns yer brane to mush also.
Its an easy experiment and yer inside the perfect laboratory eight now. Your own body.
Lord help us. Doubt he will, he’s rolling around on the floor incapacitated with laughter.
Next, how many times do we hear that iron is a limiting nutrient in watery environments.
Could iron fertilisation not be the cause of eutrophication?
Now we’re back on the ‘too many people’ meme unfortunately.
Because the iron is coming from farmland (you see red/orange coloured soils – that’s iron floating by)
You see brown coloured water rushing down rivers after a ‘rain event’ That’s farmland soil washing away and it contains (because its brown/red) iron and also, shocke horreur, phosphorus. Not least as P, when applied by farmers, ‘sticks’ to the dirt particles. It is not especially soluble. Farmland fertilisation using P (and K) only gets into rivers etc etc IF, the farmer’s soil does.
THAT is the real problem we all have= Soil Erosion and that’s what this study should have shown.
Total garbage.
Maybe it’s a measurement problem across time. Has anyone tried adding the cosmological constant?
“Our results show that urban point sources of phosphorus are the dominant cause of eutrophication of European lakes during the Anthropocene.”
The most egregious insult is that the editors let -that- word through. The International Commission on Stratigraphy doesn’t recognize the supposed time period. The International Union of Geological Sciences has received a working group recommendation but has not acted.
Mass production of flush toilets started about 1850.
Just give every environmentalist a really long straw, and tell them to start blowing.