Showing posts with label eutrophication. Show all posts
Showing posts with label eutrophication. Show all posts

Tuesday, 3 January 2012

Eutrophication... Meatrophication! A pun on so many levels!


Eutrophication; another problem (partly) caused by meat consumption.




Now I said I wanted to look into pollution caused by livestock farming in a bit more depth… so I am going out to the open ocean…lol not a very good joke is it?

There is a lot of material on the topic of eutrophication and I have already touched upon it before in some of my previous blogs and referenced some really useful sources. Here are three more!

The World Resource Institute commissioned three reports on eutrophication or as they call them ‘Policy Notes’:



The reports define eutrophication as ‘over enrichment of water by nutrients such as nitrogen – and most topically for us – phosphorous’.

Selman et al. (2008) shows the extent of the problem. In the United states and Europe’s Atlantic coastal waters, 78 and 65 % of the respective areas were exhibiting some symptoms of eutrophication. In this case symptoms of eutrophication include the most common hypoxia and algal blooms.

The severity of the problem is not widely known due to the poor monitoring of global ocean water quality. Like with many research projects funding is required; most countries especially those who face challenges of greater importance (like epidemics/droughts/famines/natural disasters/wars) simply cannot spread resources to measure a trivial data set when there are more important things to hand.

However what is known is the responses of the ecosystem. Initial growth of phytoplankton, micro-algae and macro-algae; these can cause:

  • Reduction of light penetration into waters (planets below the surface of the water cannot photosynthesise as the light is being absorbed and blocked out the excessive algal growth).
  • Benthic (bottom-dwelling) aquatic community species change, less biodiversity.
  • Algae can outcompete coral larvae for nutrients, so there is reduced coral growth.
  • A shift in the phytoplankton species composition, allowing toxic algal blooms to develop.
  • Collapse of oxygen reserves in the water resulting in ‘dead-zones’.


These symptoms damage the ecosystem and more importantly inhibit its economic potential, either directly through ecosystem servicing (what you can ‘harvest’ from the ecosystem, i.e. fishing; biodiversity; carbon sequestration) or indirectly through loss of income from reduced tourism; reduced income from fishing; recreational facilities.

Hypoxic zones exist around the world. Some of the best examples are the Gulf of Mexico (Mississippi outflow) and the Black Sea (Volga and others outflow). Particularly in the case of the Black Sea, there is a strong correlation between agricultural intensification in the 1980s and the size and rate of the hypoxic zone formation. Since the collapse of the USSR, the Black Sea has in part been in recovery.

Agriculture is not the only source of excess nutrients: human and animal sewage (…yep POO and PEE!!!), urban runoff, industrial effluent and fossil fuel combustion (not just more nutrients but more CO2 allows more photosynthesis/productivity as CO2 is generally seen as the limiting factor in plant growth).

The relative importance of the sources of nutrients is spatial. In Europe and USA, the biggest source is fertiliser application and runoff into the sea via rivers; whereas in Africa, Latin America and Asia as industrial regulations are laxer effluent is the largest contributor. Dry nitrogen deposition (from volatilisation of fertilisers) adds to eutrophication; Chesapeake Bay, in the US (as seen in an earlier post referencing Megan Smith’sblog) and the Baltic Sea in Northern Europe are good examples of this.

There is a necessity to collect information on nutrient sources and their quantities and a time series of all factors involved; from nutrient influx to chlorophyll, oxygen concentrations; quantifying the impacts on income (cost of loss of fish production, etc.). Selman et al. (2008) conclude with the importance of eutrophication to governments and the requirement to never leave it unchecked.

Selman and Greenhalgh (2009a) goes on to further highlight the significance of increased population (demographic pressures; 9.2 billion by 2050) coupled with greater demand for food and fertiliser to increase production; intensification driven by changing dietary patterns, for instance increased meant consumption up 54% from 2002 to 2030, during the same time frame energy is expected to grow 50 %. Most of the growth will occur in the developing world where there is greater vulnerability to resource pollution due to lack of funds to cope with environmental degradation and the health implications stemming from it (untreated water, spread of disease).

The tables from Selman and Greenhalgh (2009a) show nutrient sources (table 1) and percent of treated sewage (table 2).



Focusing on agricultures role in eutrophication, fertiliser leaching, runoff from agricultural fields, manure from concentrated livestock operations and aquaculture are the largest sources. Focusing on manure (a direct impact of more livestock) and fertiliser leaching and runoff (proportional to livestock feed) the relationship between eutrophication and these processes is strong. As shown from Cordell et al.’s (2009) paper with the phosphorous source graph over time, inorganic P use has tripled since the onset of the 1960s green revolution; eutrophication has also shot up. Nitrous oxides (from farts!) also add to the N used by algae. An important note is they mention that manure application to fields is timed not by necessity but by storage; when too much is in stock, they ‘fertilise’ the land, this exacerbates the run-off and leaching issue resulting in greater amounts of eutrophication. Selman and Greenhalgh cite Ellis, 2007 and Mee 2006 as studies which show poor pollution controls in China and also the production of an equivalent 5 million inhabitant city quantity of excreta from a 1 million pig farming operation in the Black Sea (respectively).

The Figures below show Meat consumption per capita against time (figure 2) and projected fertiliser consumption (figure 3) (Selman and Greenhalgh, 2009a). The link between meat consumption, fertiliser use, land use change, manure production, population growth and eutrophication is clear; ‘a by-product of unsustainable agricultural production and energy use’ (page 6).



The final report (Selman and Greenhalgh, 2009b) looks at the potential to tackle this problem. Other than the issue of monitoring which has already been looked at, they shed some light on other elements; increasing environmental awareness and greater public knowledge of the problems faced due to our consumption patterns.

Regulation and the imposing of standards in: environmental quality; pollution (effluent/emissions) capping; technology (up-to-date and efficient as well as sound).

Financial incentives like eco-taxes on environmentally degrading products (like meat); subsidies like payment for ecosystem services (PES) where a government subsidises farmers who employ an eco-friendly agricultural practice at the expense of profit – that profit is then compensated as the cost of the ecosystem service provided by the farmer (i.e. less intensive use of fertilisers, ditch management, receive £50 a month rather than production subsidies); eco-labelling and consumer awareness in the market place (successful with free range).  

Creation of protected areas via either nature preserves, sites of scientific interest, national parks which all limit the types of activity that can be performed in the area; land purchases and habitat restoration and conservation (like in Chesapeake Bay).

The requirement for institutional support is emphasised as well. Greater transparency, accountability and participation are all listed as vital to the success of schemes from the outset, to implementation, to completion. This is also the same set of criteria for what is referred to as ‘Good Governance’ in development literature.

Summing up; it is integral to sustainability that eutrophication is reversed. The issues around water quality are large. Where agriculture and livestock come into it is simple, more meat requires more fertiliser which produces more poo and other wastes! It is through the large wastes in agriculture that we get side-shows of eutrophication which further degrades our environment. What is needed as hinted to by the literature is a holistic approach, a multi-disciplinary approach involving all parts of the puzzle. There are successes highlighted in tables but that would be too much copying and pasting!!!

Please feel free to read them, especially if interested on the topic of eutrophication!

For an alternative summary please look at this site! It explains it in a much more eloquent way than I! 

Save the water! Eat less meat! (I will try!!!) :D 

Sunday, 1 January 2012

Add a little P, get a load more Poo! Part 5: P reserves and productivity!!


More on the reserves of P!

Van Vuuren et al.’s (2010) highlights predicted use of P from 1970 to 2100. Clearly they think that P reserves are going to last a while; they come to the conclusion that:

  • There are no signs of short-term to medium-term depletion
  • In the longer term, the depletion of low-cost and high-grade resources will have consequences for future production trends
  • Given the impact of resource uncertainty on the assessment of risks associated with P depletion, it is important to pay more attention to data on P resources. Uncertainty was found to play a role in data on P production,
  • Phosphate rock depletion may lead to concentrating production to a few countries, thus increasing production costs.
  • Major reductions in the use of fertiliser P can be achieved by improving plant nutrition management, better integrating of animal manure and recycling P content in human and/or animal excreta



What is most interesting about the article is that it highlights the different scenarios of P depletion; the figures show their findings:








Cordell et al. (2009) also look at the geopolitics; inequality; economics and relative irony of it all – peak oil has received a lot of attention and it is only necessary for energy and cars (I know hear me out!) whilst P is integral to crop growing, and that ever vital necessity that is food.

The figures below (taken from Cordell et al. 2009) include a pretty graph showing Phosphorous sources over time; it just shows how dependant, or as Cordell et al. puts it ‘addicted’ (2009, 292). 








With high grade P reserves being depleted (Cisse and Mrabet, 2004), and our addiction (Cordell et al. 2009), the debate as to where the next lot of P will come from, which just adds to increased food insecurity and environmental degradation due to a potential in greater mining; this leads to:

  • Greater energy use – fossil fuels and GHG emissions.
  • Greater waters usage and wastage – particularly in countries where safe water supplies are already an issue.
  • Rising prices – of P, fertilisers, agriculture and fundamentally the cost of food).



Inorganic fertiliser alone is not sufficient in restoring soil organic carbon (SOC) that forms through decomposition in situ of organic materials , and attaining the highest yields in crop production  (Su et al, 2006; Liu et al., 2010). SOC is an integral part to the soil and provides plants with capacity to grow due to its properties or absorbing water and nutrients. Fertilisers cannot provide that level of SOC; just another benefit of using manure and other waste material to fertilise the soil.

Turnerand Leytem (2004) looked into phosphorous compound sequestration from, of all things, urine. Their success in fractionating the compounds in two steps furthers the research in attaining P from readily available resources, excrement. Admittedly, this is a much more energy intensive way as well as poorly cost-effective; but it opens the doors to greater utilisation and indeed valuation of what we all poop and pee out.

So a variety of sources point to manure and other forms of excreta as a sustainable and beneficial source of P; not to mention an eventual necessary source!

Happy New Year!!! Lets hope there are a lot less cows farting this year!

Wednesday, 28 December 2011

Add a little P, get a load more Poo! Part 4: P reserves and losses!



Cordell et al. (2009)’s paper on the story of phosphorous is a MUST READ! 

It is packed full of information on the subject… but I will try my best to extract the useful information. Being half Moroccan (half Italian), I can’t help but rub my hands with glee… the largest stores of P are locating in the country (regardless of what anyone says, Western Sahara does not exist in Morocco; we call the southern provinces… moving swiftly on…!) as shown in the figure below from Elser and Bennet (2011). 


This is however a big problem in terms of global securities and power balances. With turmoil in north Africa and the apparent ‘revolutions’ reaching their 1st birthday, it is more important than ever that food and the fertiliser used, does not fall into the same fate as it did 3-4 years back with the large prices rises in grains (Elser and Bennet, 2011). 700% price rise in P coupled with the price rise signalled a warning light to governments worldwide. However, as Cordell et al. (2009) and Elser and Bennet (2011) note, the world still is not reacting to this train wreck; they can’t even pull their act together on gas emissions and the Kyoto agreement (COP Durban 2011 round of talks).

One thing is for sure is that if we use less, costs will go down and we are less dependent on another out-sourced commodity that everyone needs. If we all became vegetarian, then we would require significantly less P than a meat based diet, and most of the crop can easily be returned to the soil as residue, recycling most of the P used as a fertiliser. Even so; the largest wastage of P originates in the poor application of fertilisers to soils (8 million tonnes, MT). Leeching of the synthetically produced nutrients results in massive inefficiencies in P management; contaminating ground, surface and coastal waters with high levels of nutrients had led to vast amounts of eutrophication.

Eutrophication is when nutrients (either via leeching direct from fertilisers or poor waste management) added to water bodies causes the growth of organisms; algal blooms are a common example of added nutrients altering the natural ecology of a body of water (lake, sea, estuary, etc.). (Smithand Schindler, 2009) The blooms photosynthesis at high rates, starving most other organisms of oxygen (increased when the blooms die and decompose); creating a hypoxic environment.

Please read more on eutrophication in these sites:



Back to wastes of P and as the figure above (Cordell et al. 2009) suggests, 14/17.5 MT of P go to agriculture; of that only 3 MT make it to our forks. 8 MT is wasted through poor application, and of the 3 MT we consume as food, 1 MT is wasted as spoiled food. By just eating within our means we save 1 MT. through better fertiliser management techniques with save an extra 8 MT. It is easier said than done, but through accurate monitoring of soil nutrient levels, we can guage whether or not the land needs to be fertilised, saving energy, money and effort as well as P. Using more natural fertiliser we can solve some of the problems, by no means is sh… poo a panacea for eutrophication/power insecurities/commodity prices/waste management/agricultural productivity and the like, but it is a step in the right direction!

Reserves of P aren't well documented globally, in fact many researches, scientists, geologists and mad hatters disagree as to how much P there is under ground. Cordell et al. (2009) explores this using a number of different scenarios showing just how long it would take, depending on how much P we need, to finally hit the last nail on the head of the coffin that would be global inorganic P reserves. 

Next part coming soon!

Thursday, 15 December 2011

Add a little P, get a load more Poo! Part 3: Video time...AGIAN!


This video is from an Australian Broadcasting Corporation (ABC) did a special on... you guessed it, peak P!


It is a really interesting video investigating the potential for utilising urine for nutrient extraction. I love the toilet! However, the man said that men will have to sit down... errr has anyone ever told him men can aim where they pee? This is very disturbing....


There is also a related article on the website. Please read!