Showing posts with label spirulina. Show all posts
Showing posts with label spirulina. Show all posts

Thursday 11 October 2018

Sonic booms and algal blooms: a smart approach to detoxifying waterways

A recent report here in New Zealand has raised some interesting issues around data interpretation and the need for independent analysis to minimise bias. The study has examined the state of our fresh water environment over the past decade, leading to the conclusion that our lakes and rivers are improving in water quality.

However, some of the data fails to support this: populations of freshwater macro invertebrates remain low, following a steady decline over many decades. Therefore while the overall tone of the report is one of optimism, some researchers have claimed that the data has been deliberately cherry-picked in order to present as positive a result as possible.

Of course, there are countless examples of interested parties skewing scientific data for their own ends, with government organisations and private corporations among the most common culprits. In this case, the recorded drop in nitrate levels has been promoted at the expense of the continued low population of small-scale fauna. You might well ask what use these worms, snails and insects are, but even a basic understanding of food webs shows that numerous native bird and freshwater fish species rely on these invertebrates for food. As I've mentioned so often the apparently insignificant may play a fundamental role in sustaining human agriculture (yes, some other species practice farming too!)

So what is it that is preventing the invertebrates' recovery? The answer seems to be an increase in photosynthetic cyanobacteria, or as is more commonly - and incorrectly known - blue-green algae. If it is identified at all, it's as a health food supplement called spirulina, available in smoothies and tablet form. However, most cyanobacteria species are not nearly as useful - or pleasant. To start with, their presence in water lowers the oxygen content, so thanks to fertiliser runoff - nitrogen and phosphorus in particular - they bloom exponentially wherever intensive farming occurs close to fresh water courses. Another agriculture-related issue is due to clearing the land for grazing: without trees to provide shade, rivers and streams grow warmer, encouraging algal growth. Therefore as global temperatures rise, climate change is having yet another negative effect on the environment.

Most species of cyanobacteria contain toxins that can severely affect animals much larger than fresh water snails. Dogs have been reported as dying in as little as a quarter of an hour from eating it, with New Zealand alone losing over one hundred and fifty pet canines in the past fifteen years; it's difficult to prevent consumption, since dogs seem to love the smell! Kiwis are no stranger to the phylum for other reasons, as over one hundred New Zealand rivers and lakes have been closed to swimmers since 2011 due to cyanobacterial contamination.

Exposure to contaminated water or eating fish from such an environment is enough to cause external irritation to humans and may even damage our internal organs and nervous system. Drinking water containing blue-green algae is even worse; considering their comparable size to some dogs, it is supposed that exposure could prove fatal to young children. Research conducted over the past few years also suggests that high-level contamination can lead to Lou Gehrig's disease, A.K.A. amyotrophic lateral sclerosis, the same condition that Stephen Hawking suffered from.

What research you might ask is being done to discover a solution to this unpleasant organism? Chemicals additives including copper sulphate and calcium hypochlorite have been tried, but many are highly expensive while the toxicity of others is such that fish and crustacean populations also suffer, so this is hardly a suitable answer.

A more elegant solution has been under trial for the past two years, namely the use of ultrasound to sink the blue-green algae too deep to effectively photosynthesise, thus slowly killing it. A joint programme between New Zealand and the Netherlands uses a high-tech approach to identifying and destroying ninety per cent of each bloom. Whereas previous ultrasonic methods tended to be too powerful, thereby releasing algal toxins into the water, the new technique directly targets the individual algal species. Six tests per hour are used to assess water quality and detect the species to be eradicated. Once identified, the sonic blasts are calibrated for the target species and water condition, leading to a slower death for the blue-green algae that avoids cell wall rupture and so prevents the toxins from escaping.

Back to the earlier comment as to why the report's conclusions appear to have placed a positive spin that is unwarranted, the current and previous New Zealand Governments have announced initiatives to clean up our environment and so live up to the tourist slogan of '100% Pure'. The latest scheme requires making ninety percent of the nation's fresh water environments swimmable by 2040, which seems to be something of a tall order without radical changes to agriculture and the heavily polluting dairy sector in particular. Therefore the use of finely target sonic blasting couldn't come a moment too soon.

Our greed and short-sightedness has allowed cyanobacteria to greatly increase at the expense of the freshwater ecosystem, not to mention domesticated animals. Now advanced but small-scale technology has been developed to reduce it to non-toxic levels, but is yet to be implemented beyond the trial stage. Hopefully this eradication method will become widespread in the near future, a small victory in our enormous fight to right the wrongs of over-exploitation of the environment. But as with DDT, CFCs and numerous others, it does make me wonder how many more man-made time bombs could be ticking out there...

Monday 26 June 2017

The power of pond scum: are microalgae biofuels a realistic proposition?

I've previously discussed some very humble organisms but they don't get much humbler than microalgae, photosynthetic organisms that generate about half our planet's atmospheric oxygen. Imagine then what potential there might be for their exploitation in a world of genetic manipulation and small-scale engineering? The total number of algal species is unknown, but estimates suggest some hundreds of thousands. To this end, private companies and government projects around the world have spent the past few decades - and a not inconsiderable amount of funding - to generate a replacement for fossil fuels based on these tiny plants.

For anyone with even a microgram's worth of common sense, developing eco-friendly substitutes for oil, coal and gas is a consummation to be devoutly wished for, but behind the hype surrounding microalgae-derived fuel there is a wealth of opposing opinions and potential some shady goings-on. Whilst other projects such as creating ethanol from food crops are continuing, the great hope - and hype -that surrounded algae-based solutions appears to be grinding to a halt.

Various companies were forecasting that 2012 would be the year that the technology achieved commercial viability, but this now appears to be rather over-eager. Therefore it's worth exploring what happens when hope, high-value commerce and cutting-edge technology meet. There are some big names involved in the research too: ExxonMobil, Shell and BP each pumped tens to hundreds of millions of dollars into microalgae fuel projects, only to either make substantial funding cuts or shut them down altogether since 2011.
Microalgae-derived biofuel
Manufacturing giants such as General Electric and Boeing have been involved in research for new marine and aircraft fuels, whilst the US Navy undertook tests in 2012 whereby algae-derived fuel was included in a 50:50 blend with conventional fossil fuel for ships and naval aircraft. Even shipping companies have become interested, with one boffin-worthy idea being for large cruise ships to grow and process their own fuel on-board. Carriers including United Airlines, Qantas, KLM and Air New Zealand have invested in these kerosene-replacement technologies, with the first two of these airlines having trialled fuel blends including 40% algae derivative. So what has gone wrong?

The issue appears to be one of scale: after initial success with laboratory-sized testing, the expansion to commercial production has encountered a range of obstacles that will most likely delay widespread implementation for at least another quarter century.

The main problems are these:
  1. The algae growing tanks need to be on millions of acres of flat land and there are arguments there just isn't enough such land in convenient locations.
  2. The growing process requires lots of water, which means large transportation costs to get the water to the production sites. Although waste water is usable, some estimates suggest there is not enough of this - even in the USA - for optimal production.
  3. Nitrogen and phosphorus are required as fertiliser, further reducing commercial viability. Some estimates suggest half the USA's annual phosphorus amount would need to be requisitioned for use in this one sector!
  4. Contamination by protozoans and fungi can rapidly destroy a growing pond's entire culture.
In 2012 the US National Academy of Sciences appeared to have confirmed these unfortunate issues. Reporting on the Department of Energy goal to replace 5% of the nation's vehicle fossil fuel consumption with algae-derived biofuel, the Academy stated that this scale of production would make unfeasibly large impacts on water and nutrient usage, as well heavy commitments from other energy sources.

In a bid to maintain solvency, some independent research companies appear to have minimised such issues for as long as possible, finally diversifying when it appeared their funding was about to be curtailed or cut-off. As with nuclear fusion research, commercial production of microalgae fuels hold much promise, but those holding the purse strings aren't as patient as the researchers.

There may be a hint of a silver lining to all this, even if wide scale operations are postponed many decades. The microalgae genus Chlorella - subject of a Scottish biofuel study - is proving to be a practical source of dietary supplements, from vitamins and minerals to Omega-3. It only lacks vitamin B12, but is an astonishing 50-60% protein by weight. As well as human consumption, both livestock and aquaculture feed supplements can be derived from microalgae, although as usual there is a wealth of pseudoscientific nonsense in the marketing, such as the notion that it has an almost magical detox capability. Incidentally, Spirulina, the tablets and powder sold in health food outlets to make into green gloop smoothies, is not microalgae but a B12-rich cyanobacteria, colloquially - and confusingly - known as blue-green algae. Glad that's cleared that one up!

If anything, the research into microalgae-derived biofuels is a good example of how new technology and commercial enterprise uneasily co-exist; each needs the other, but gaining a workable compromise is perhaps just a tricky as the research itself. As for Government-funded projects towards a better future for all, I'll leave you to decide where the interests of our current leaders lie...