Future ocean conditions could cause significant physical changes in
marine mussels

Date:
October 9, 2020
Source:
University of Plymouth
Summary:
Scientists showed increased temperature and acidification of our
oceans over the next century could have a range of effects on an
economically important marine species.



FULL STORY ==========================================================================
The increased temperature and acidification of our oceans over the next
century have been argued to cause significant physical changes in an economically important marine species.


========================================================================== Scientists from the University of Plymouth exposed blue mussels (Mytilus edulis) to current and future levels of ocean acidification (OA) or
warming (W), as well as both together -- commonly known as OAW.

Initial comparison of mussel shells showed that warming alone led to
increased shell growth, but increasing warming and acidification led to decreased shell growth indicating that OA was dissolving their shells.

However, analysis using cutting edge electron microscopy of the shell
crystal matrix or 'ultrastructure' revealed that, in fact, warming alone
has the potential to significantly alter the physical properties of the mussels' shells, whereas acidification mitigated some of the negative
effects.

Mussels grown under warming exhibited changes in their crystal structures including a propensity for increased brittleness, which would place
mussels under greater threat from their many predators including crabs
and starfish.

These negative effects were to some degree mitigated under acidified
conditions with mussel shells showing evidence of repair, even though
their crystals grew differently to the norm.

The study, published in a Frontiers of Marine Science special issue
titled Global Change and the Future Ocean, is the latest research by the University into the potential effects of ocean warming and acidification
on marine species.

Previous projects have suggested future conditions could significantly
reduce the nutritional qualities of oysters as well as dissolving the
shells of sea snails and reducing their overall size by around a third.

Dr Antony Knights, Associate Professor in Marine Ecology and the study's
lead author, said: "By the end of the century, we are predicted to see increases in sea surface temperature of 2-4DEGC and at least a doubling
of atmospheric CO2.

It is no surprise that would have an effect on marine species, but this research is surprising in that acidification appears to mitigate changes
in shell structure attributable to rising sea temperatures, which is
counter to what we would have predicted. It may be that increased CO2
in the water is providing more 'raw material' for the mussels to repair
their shells that is not available under just warming conditions."
Dr Natasha Stephen, Director of Plymouth Electron Microscopy Centre,
added: "Until now, there have been relatively few studies assessing
the combined effects of ocean acidification and warming on shell
structures. However, understanding the changes that might result at a microscopic level may provide important insights in to how organisms
will respond to future climate change.

This study shows it can certainly have negative effects but also that they
are not always predictable, which presents some serious challenges when
it comes to trying to disentangle the consequences of climate change."

========================================================================== Story Source: Materials provided by University_of_Plymouth. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Antony M. Knights, Matthew J. Norton, Anae"lle J. Lemasson, Natasha
Stephen. Ocean Acidification Mitigates the Negative Effects of
Increased Sea Temperatures on the Biomineralization and Crystalline
Ultrastructure of Mytilus. Frontiers in Marine Science, 2020;
7 DOI: 10.3389/ fmars.2020.567228 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201009094946.htm

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