From Eurekalert: (no comment ~ctm)
University of Plymouth
The nutritional qualities of shellfish could be significantly reduced by future ocean acidification and warming, a new study suggests.
Research has previously shown that climate change could threaten future production, safety and quality by negatively impacting the fitness of marine species.
Now scientists from the University of Plymouth, in a study published in Marine Environmental Research, have demonstrated the potential for negative nutritional effects within economically and commercially valuable species.
The research focussed on the Pacific oyster (Magallana gigas) and the native flat oyster (Ostrea edulis), with results showing that increased temperatures and CO2 levels could significantly reduce the former’s levels of proteins, lipids and carbohydrates.
With seafood being the source of more than 15% of animal protein consumed globally, scientists say the aquaculture industry may wish to consider a shift in focus toward species that are most robust to climate change and less prone to deterioration in quality.
Dr Anaëlle Lemasson, a former PhD student at the University, led the research having previously shown that although the physiology of the Pacific oyster can be negatively impacted by future climate change, its taste might not be adversely affected.
She said: “Identifying changes in nutritional quality, as well as species most at risk, is crucial if societies are to secure food production. Our previous research had suggested there could be negative effects in the conditions predicted to occur in 2050 and 2100. However the fact that Pacific oysters, which currently accounts for around 90% of UK oyster production, can be affected could be a cause for concern.”
The research was conducted by scientists linked to the University’s Marine Biology and Ecology Research Centre (MBERC) and the Food, Health and Nutrition research group.
MBERC is one of the world’s leading research centres examining the impact of multiple stressors on marine organisms and environments, and undergraduate and postgraduate students are regularly involved in that research.
The oysters were subjected to six different sets of ocean conditions over a 12-week period, from current temperatures and CO2 levels to the increased measurements predicted for both the middle and end of the century.
As well as changes in nutrient levels, researchers also observed important changes to essential mineral composition, adding that the enhanced accumulation of copper in Pacific oysters may be of future concern in terms of consumption safety.
Dr Victor Kuri, Lecturer in Food Quality at the University, said: “With a low environmental impact, shellfish are a promising highly nutritious alternative to fish and other animal products, but their sustainability depends on their quality attributes including palatability, nutrition and safety. This work confirms the need to understand the science behind the risks and mechanisms of shellfish production, as this knowledge is needed to build adequate resilience in harvesting and aquaculture industries”
Dr Antony Knights, Associate Professor in Marine Ecology, added: “Climate change and the growing global population are placing arguably unsustainable demands on sources of animal protein. This comes at a time when increased obesity in several regions of the world is leading to greater public awareness of the need for healthy and balanced diets. Oysters have the potential to be a sustainable, low-cost alternative source of protein for humans. Our native flat oyster, in particular, appears to be more resilient to future climate change scenarios than introduced Pacific oysters making them a great aquaculture choice and supports the growing investment in this product in the UK.”
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Don’t you just love this type of studies? GW “could” impact, bla bla bla. We “could” be hit with a giant asteroid next month.
From the abstract
“…..enhanced accumulation of copper in M. gigas may be of concern regarding consumption safety.” https://www.sciencedirect.com/science/article/pii/S0141113618304161
The paper is paywalled, but I will eventually get it. I am still a member of the National Shellfisheries Association from work I did after my master’s almost 6 decades ago at the then Virginia Fisheries Laboratory (now Institute of Marine Science putting out fish skeletons on Google Earth, but I digress). I just got the last issue of their journal whose lead article is on the life cycle of MSX, a sporozoan parasite, probably exotic, that appeared and caused extensive mortality first in Delaware and then Chesapeake Bays in the late 50s-early 60s.
The MSX life cycle is still unknown 6 decades later, the paper examining rDNA signatures by PCR hybridization in water, sediment, (some positive) and some associated macroinvertebrates (negative). The main American oyster (Crassostrea) scavenger is a fish (goby) and similar fishes occur elsewhere using shells to deposit their eggs. The European and others (Flat) oysters (Ostrea, Magallana) are different and are considered (tastewise) inferior, noted by the early 17th century French explorers in Louisiana.
Similarly green oysters from copper (also can be green in gills from phytoplankton) showing in all their tissues, have been known since forever, and have even been suggested to enhance their taste. I have eaten all these, and a couple of others, but never a green one, although I have seen them. Oyster accumulate everything, but are good at depuration.
I mention all this because all this appears to be another casualty of the technological (DNA etc.) and environmental revolutions (blame humans). MSX cannot be transmitted directly, but a 1960s experiment at the Chesapeake Biological Laboratory was apparently successful but the presumed intermediate host (usual for Sporozoa, malaria the best known) was not determined. Apparently no gross anatomy experiment has been done since, despite its long success in determining life cycles, including one on another Sporozoan oyster parasite.
Also, this may be a victim of the current sequestration fad, oyster shells to collect the demons, first nitrogen, now even carbon dioxide. Apparently they have no knowledge of thermodynamics, like mass balance, and there is, as they say, a robust literature on shell longevity and chemistry. It might work a little if we go back to putting oyster shells on roads.
The Chesapeake situation is complex, blamed on overfishing, hypoxia, and they even tried another exotic oyster, failed, an experiment also tried and rapidly abandoned in the early 1940s in Louisiana. Homework is not a strong discipline anymore. There is a lot more, but have to end with this (1877, translation mine) from the German biologist Karl Möbius, who coined the word biocoenosis from studies of the European oyster, which led to the ecosystem idea.
“When great numbers of oysters from the rich banks of Cancale, Rochefort, Marennes and d’Oléron were removed, as many living places and nourishment were available as before, and so great numbers of cockles and mussels appeared. The Biocoenoses of the former French oyster banks were totally changed through overfishing. Not until the numbers of cockles and mussels return to their originally small existence, can the same numbers of oysters be rebuilt because the bottoms are already used by other mollusks taking away the nourishment.”
We used to get all sorts of “given global warming, . . . .” studies.
Looks like we are now going to get “given global warming AND ocean acidification, . . . .” studies.
What’s next?
“Given global warming AND ocean acidification AND declining oxygen levels, . . . .” studies?
This raises the question, while it is not reasonable to eat oyster shells, is there a problem with eating prawn shells? Obviously eating prawn heads may be a bit hard, and there is not much nutrition in prawn tails, but eating the rest, the overlocking shell segments with the internal meat makes them quite crunchy and delicious. Am I the only person who enjoys the shells?
There are apparently no effects in the stomach and lower down – are the shells completely dissolved in the stomach acid?
Reduced lipids (“fat”) & reduced carbohydrate oysters will satisfy a lot of dueling dietary advocates. On alternate blogs we’ll see them touted as the ideal “low carb” or the superb “low fat” ingredient.
Great marketing idea!!!!
If and I repeat if the oceans warmed by the amount stated with the rise in CO2 as well how do they think the little critters cope with diurnal and seasonal changes in both these supposed stressors that are going to do them such harm in a hundred years time.
James Bull
In addition, if you check out my link above, you will see that the seasonal changes in oceanic CO2 can completely dwarf the relatively small seasonal changes in atmospheric CO2 (as well as the circa 2 ppm per year growth rate).
We grow oysters under our dock on the southern Chesapeake Bay. The worst thing for them is nutrient pollution of the water, which slows down their growth tremendously. The second is salinity changes mostly due to heavy rains (or no rains).
The water temperatures don’t seem to matter much unless it gets too cold in the winter. We get skim ice occasionally and the oysters that get exposed to the ice can die. The ones deeper make it through just fine.
This is akin to doll houses and play sets. Only she is using, or misusing, far more complex saltwater aquariums for her doll house and nutrient dependent animals as her dolls.
Then she subjects the critters to higher CO₂ and higher temperatures according to prophesied temperatures according to some model gospel. Unstated in this press research, and frankly, I’m not interested in chasing her imaginary future temperatures down.
The bald fact is that water temperatures where oysters live have barely changed. NOAA changed their temperatures to joules, so the numbers would sound scary. It also allowed NOAA to hide the fact that most of their claimed temperature increases were within instrument error ranges.
All of which makes Dr Anaëlle Lemasson’s playing with little oyster dolls, unverified, untested, uncertified, unreplicated, un-independent verified.
What’s amazing is that she got paid for this playtime.
Anyone who will eat a lump of living snot deserves everything they get.
So they took current oysters and subjected them (with no time for adaption) to conditions that might occur decades from now? This is science?
I could take 5 year-olds and ask them to drive a car, like they might in 10 or 20 years, and then conclude that it is impossible that they will be able to drive cars in the future.
The nutritional qualities of shellfish could be significantly reduced by future ocean acidification and warming, a new study suggests.
Research has previously shown that climate change could threaten future production, safety and quality by negatively impacting the fitness of marine species.
The oysters were subjected to six different sets of ocean conditions over a 12-week period.
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the next study will expose test sheep 6 different falling Heights to determine the resulting damages.