Sydney rock oysters getting smaller as oceans become more acidic due to climate change
EVERYTHING is caused by climate change! The study behind the article below does not yet appear to be online. None of my usual search techniques located it anyway. So I am a bit handicapped in commenting on it.
I would for instance like to know details of the survey technique they used to arrive at their conclusion that Sydney oysters are are shrinking. Without representative sampling no generalizations are possible. My bet is that they did not do comprehensive and representative sampling.
But in the absence of that information, we can still detect some dubious conclusions. If there has been a decline, how do we know it is due to global warming? We do not know. There could be many other causes of the effect. The most obvious alternative cause would be disease. Oysters are prone to all sorts of disease stressors: QX disease, POMS disease and many more. And given the frequency of such attacks there are probably some as yet undetected diseases at work.
Oyster farmers believe that acidic runoff from the land adversely affect oysters. Susan Fitzer says that has recently been reduced but again I would like details of that assertion and the surveys on which it is based.
And sewage runoff is known to affect oysters. And there seems little doubt that the breakneck expansion of the Sydney population is putting a lot more sewage into the ocean. (Yes. Sydney does do that). Could that adversely affect oysters?
And the alleged acidity is in fact reduced alkalinity. Does any level of alkalinity affect oysters? I can't see why it should.
And the "acidity" is said to be a result of increased global warming. But, according to the satellites, global temperatures have been falling for the last couple of years.
Furthermore the entire prediction that acidity will increase in the oceans is deliberately dishonest. If, as Warmists predict, the world will warm, that will make the oceans warmer too. And as water warms it OUTGASES CO2, as every drinker of coca cola can observe. Those bubbles in your coke are outgassed bubbles of CO2, outgassed as the drink warms. And less CO2 means less carbonic acid. So a warming ocean will become more ALKALINE.
The Warmists try to have it both ways, saying the oceans will be both warmer and more acidic. But that flies in the face of basic and easily demonstrable physics. But they are only pretend scientists so I guess that is OK
And we read here that ancient planktonic foraminifer shells were still going strong at CO2 levels 5 times higher than today. That sounds like a good augury for oyster shells.
So I think we can say with some confidence that the causal chain suggested by Susan Fitzer is rubbish on a number of counts
The famous Sydney rock oyster is shrinking as oceans become more acidic, new research has found.
In news that will rock seafood lovers, a study released overnight by academics in the UK found oysters in New South Wales have become smaller and fewer in number because of coastal acidification.
It’s part of what researchers fear is a worldwide trend driven by climate change and coastal runoff.
Headed by University of Stirling academic Susan Fitzer, the study looked at oyster leases at Wallis Lake and Port Stephens, both on the NSW coast north of Sydney.
They make up the two largest Sydney rock oyster production areas in NSW.
The study found the oysters’ diminishing size and falling population is due to acidification from land and sea sources, part of a global trend.
“Sydney rock oysters are becoming smaller and their population is decreasing as a result of coastal acidification,” Fitzer said.
“The first thing consumers will notice is smaller oysters, mussels and other molluscs on their plates, but if ocean acidification and coastal acidification are exacerbated by future climate change and sea level rise, this could have a huge impact on commercial aquaculture and populations around the world.”
The risk to oyster populations around the globe from soil runoff has long been recognised.
In 2014 oyster farmers in Port Stephens released an industry-driven environmental management policy which recognised that damage to oyster leases from the drainage from acid-sulphate soils was both “likely” to occur and “severe” in consequence.
But Fitzer’s research argues that run-off is not caused by agricultural activity and is rather the consequence of the impacts of climate change.
“A lot of work has been done near to Australia’s oyster fisheries to mitigate the impact of sulphate soils causing acidification, and there has been a marked decline in levels,” she said.
“The run-off from sulfate soils aren’t produced by agricultural activity, they occur as a natural result of climate change-driven increases in rainfall and sea-level rise.
“But the trend persists and small changes in pH are having a huge impact on these molluscs.”
Increased acidification affects oyster growth by limiting the amount of carbonate in the water.
“Acidic water is damaging oysters’ ability to grow their shells. We see lots of disorder in the calcite layers, because there isn’t enough carbonate in the water for the oysters to draw on for optimal shell formation and growth,” Fitzer said.
“This is the first time that the Sydney rock oysters’ shell crystallography has been studied, and we now know disruption to this process could have a significant impact on Australian aquaculture,” she said.
Fitzer’s research was published in the Journal of Ecology and Environment.