Diatoms can’t be wrong.
So The Boss says anyway.
We were on the river this morning and The Boss was rattling on about these diatoms. I was trying to be understanding, after giving chase to a rather large wallaby.
And having run out of breath I was naturally trying to look attentive. So you’d better stick with me – because I had to.
He says diatoms are these tiny cells in plankton that tell scientists where they came from – whether they tolerate fresh water or salt water or a bit of both. Like, for the last 7000 years.
It’s become a big issue after the leading expert on diatoms in Australia, Professor Peter Gell, showed how a report he oversaw on the lower lakes of the Murray River – back in 2007 – had been subsequently “re-interpreted” to say pretty much the opposite thing, in 2009.
Professor Peter Gell is a palaeoecologist who examines change in the condition of wetlands over, like, ancient periods of time. Diatoms are his go.
The Boss says the Professor specialises in the use of diatoms as indicators of present, and past, river and lake conditions, particularly in coastal systems and across Australia's Murray Darling Basin.
In 2007, he published a paper which concluded, in part, that independent evidence from water quality indicators (those little diatoms) preserved in the Lake Alexandrina sediment records “attested to an estuarine, albeit variable, condition before the commissioning of near-mouth barrages in 1940.”
But then he says: “This interpretation for a naturally estuarine history, published after peer review, was overlooked in a report to the South Australian government, which argued, without the provision of new evidence from the lakes, that they were fresh for their entire history.”
What does “overlooked” mean, you might well ask?
Well, this is what Professor Gell’s report said in 2007:
“The presence of Thalassiosira lacustris, Cyclotella striata and Paralia sulcata indicate marine influence at this time…the change in diatom community [after 5000 years BP] is likely to
represent a decrease in lake level and increased penetration of seawater, possibly associated with the variable, dry climate.”
And here’s what the 2009 paper said, prepared for the South Australian Government – although it was never “peer reviewed” and given the testing, by other experts, of the first paper:
“The presence of Thalassiosira lacustris, Cyclotella striata and Paralia sulcata indicate minor marine influence at this time…the change in diatom community [after 5000 years BP] is likely to
represent a decrease in lake level and increased penetration of more brackish water, possibly associated with the variable, dry climate.”
I’m just about losing The Boss by this point, what with a hare getting up down the track – although I’ve realised those hares that look the size of a terrier are a bit too quick for me.
The Boss says two of the authors of the later 2009 report also worked with Professor Gell on the 2007 report – Associate Professor John Tibby and Dr. Jennie Fluin – they were apparently Professor Gell’s post-doctoral and doctoral researchers at the time.
Professor Gell left the University of Adelaide after that to return to Victoria. A couple of years later Tibby and Fluin, along with another, produced this “altered” report for the South Australian government – changing some words, but apparently without any new evidence.
Why would they do that? It looks like they fudged the science, just a bit, didn’t they? Unfortunately, a lot of people (particularly the South Australian Government) used it to argue that the lower lakes have always been freshwater lakes and, in turn, justify maintaining the artificial barrages down near Goolwa to keep them that way.
That led, in turn, for the Murray Darling Plan to demand that sufficient flows move down the Murray to maintain these “freshwater lakes” - which evaporate around nine hundred billion litres a year. This is more than the entire water resource available to irrigators in the GMID.
[Professor Gell lists seven "scientific papers" which have relied on the false interpretation of the 2007 report to argue that the lower lakes have always been fresh. It's an amazing read, even for a dumb dog like me. Read it below - it took me three goes!]
This is a disgraceful waste of valuable fresh water, The Boss says.
And this is despite the expert Professor Gell’s conclusion, based on hard evidence, that “the continuous presence of marine species and the dominance of the euryhaline Staurosirella pinnata indicate that…Lake Alexandrina was always an estuary and could not be defined as predominantly fresh until the construction of the barrages.”
It stands to reason, The Boss says, that the Murray mouth was an estuary like any other estuary in the country, with marine flows being dominant sometimes and freshwater river flows being dominant at other times, depending on floods, drought, storm surges and wind conditions.
He says the fisherman in the lower lakes – once teeming with saltwater species like Mulloway – always talked about “the blue line” between salt and fresh – like most other estuaries.
“It’s nonsense, General. Fudging science has cost us very dearly.”