Saturday 12 January 2019

The Devil in the Details: Algal Blooms.

It is accepted that the recent mass fish kill in the Darling River was triggered by an “algal bloom”. But what on earth is an algal bloom?

Believe it or not, I think some basic, high-school level science could throw considerable light on the whole catastrophe, counter some misconceptions about it and offer valuable, if sobering, lessons for the Left.

Photomicrograph of cyanobacteria, Cylindrospermum sp.[A]

The first detail is that those “blue-green algae” -- more generally referred to as “algae”, period -- behind the bloom strictly speaking aren’t algae: BGA are unicellular, microscopic aquatic bacteria (cyanobacteria, to be precise). Although genuine algae can be unicellular, algae are plants, not bacteria.

BGA, however, do something very unlike other bacteria. They, like plants, photosynthesise:

6 CO + 6 H O --> C H  O  + 6 O
    2     2       6 12 6      2

BGA use energy in the environment (from sunlight, not shown in the equation; that’s the “photo-” prefix) to break down carbon dioxide (CO2) and water (H2O) into its constituent atoms and to “reassemble” them into glucose (C6H12O6) and oxygen (O2): i.e. synthesise those molecules. Some of the energy is stored within the glucose.

During the day, BGA release the oxygen into the environment and accumulate glucose, which they use at night (together with oxygen) for the energy it contains (reversing the equation above: cellular respiration):

C H  O  + 6 O  --> 6 CO  + 6 H O
 6 12 6      2         2      2

Any excess glucose goes into reproducing themselves.

So, like plants, cyanobacteria require water, carbon dioxide (dissolved in the water), light and warmth to survive. All of that, considering their tiny size, is often readily available in their environment.

That, however, is not their complete list of requirements. Like plants, they also need other nutrients, like phosphorus and nitrogen. That can be harder to find.

In their natural environment, nutrient availability constrains define the life-cycle of cyanobacteria: they reproduce to the extent those constrains allow, photosynthesise, net-release oxygen and accumulate glucose. Some die naturally, some are eaten by other organisms and some reproduce. The oxygen and glucose they produce sustain other life forms.

Important human sources of those more naturally scarce nutrients, however, can disturb that cycle: agricultural run-off (plant fertilisers!) and sewerage (human manure!). Farmers deliberately employ fertilisers to promote plant growth. Shouldn’t one expect fertilisers to promote BGA growth?

In a flowing course of water, water inflows can keep the concentration of carbon dioxide and phosphorus and nitrogen compounds low enough. Of course, eventually they will still reach the ocean, where they may trigger algal blooms. But the algal bloom in the inland course of water was averted.

Bacterial bloom south of Fiji on October 18, 2010.[B]

Now, there’s no prize to guess what could happen in hot, sunny days, if the water, because of drought, over-extraction or a combination, stopped flowing: BGA multiply explosively -- algal bloom. All the while, BGA remain bacteria, producing more bacteria-like effects: some of them release toxins.

Eventually, some of those conditions falter (say, temperature and/or luminosity falls) and a mass die-off ensues.

Other bacteria present in the environment feast on the glucose the BGA accumulated, reproducing beyond measure, consuming the oxygen the BGA released and releasing in turn the carbon dioxide BGA had consumed. They do what the second equation indicates.

After suffocating larger life forms unable to leave the area affected, these latter bacteria themselves die.

The end situation is similar to the initial one: concentrated carbon dioxide and phosphorus and nitrogen compounds. Is it conceivable this process could repeat itself? Well, yes. Yes, it is conceivable.


The purpose of this post exceeds delivering a high-school level lecture on science. Neither do I aim to deny the tragic and ominous nature of the events, quite to the contrary. It’s not my intention to cast doubt on the sincerity of the feelings those directly affected expressed. I truly believe you all and I know your situation is really dire. To make things worse, we might not have seen the end of this.

I agree this episode demands great scrutiny of large cotton growers and their links to bureaucrats/politicians. It’s likely that the former exceeded their water entitlements thereby turning a bad situation into an environmental disaster. They, however, aren’t the only large water users or the only large contributors to algal blooms.

It’s likely, too, that bureaucracy and parties were captured by those big farmers; corruption isn’t out of the question. However, governmental ineptitude and simple, garden-variety impotence aren’t out of the question, either: the government may have failed to act when action could have prevented or minimised things; but that was then and this is now. And now they just can’t make it rain. To manage capitalism looks more and more like a fool’s errand.

My point is that the situation is more complex than it seems. To deny that does a disservice to us all.

The Darling catastrophe could be a smallish dress rehearsal for what is to come at much larger scale (I’m not kidding: put yourself in the shoes of the second bacteria.). Everybody, but particularly Lefties (I’m looking at you, MMTers), should pay attention.

Let me sum up my conclusion: excessive faith in governmental technocratic management and too much business for too little natural resources was the road to this chaos.


What Exactly Is a Red Tide?
By Danielle Hall, August 2018

Toxic Algal Blooms
Department of Primary Industries and Regional Development
Government of Western Australia, page last updated: Thursday, 4 January 2018 - 1:33pm

[A] "Photomicrograph of cyanobacteria, Cylindrospermum sp. Cyanobacteria are capable of nitrogen fixation, which takes place in the anaerobic environment of heterocysts". Author: Matthew Parker. 22 January 2013. Source: Wikimedia. File licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. Nobody endorses me or the use I make of that file.

[B] "Bacterial bloom south of Fiji on October 18, 2010. Though it is impossible to identify the species from space, it is likely that the yellow-green filaments are miles-long colonies of Trichodesmium, a form of cyanobacteria often found in tropical waters".
Author: Norman Kuring, NASA Earth Observatory. Source: Wikimedia. Public domain.

13-01-2019. Although this appeared yesterday, I've just read it. Check the underlined within the brief summary, at the bottom:


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