Today you're hearing from Melissa May, a doctoral student in marine biology at the University of Maine, about her work studying how mussels respond to changes in salinity. For this post, we're switching from freshwater to saltwater mussels in our series.
Sure, being a marine biologist is awesome, but it’s not all whales and ocean excursions.
Most of us spend a fair amount of time in the laboratory, bent over microscopes or analyzing data. And, more often than not, our research subjects resemble slimy blobs instead of adorable animals. But, we lab rats get a different perspective of the world. We see inside the cells, we manipulate the unseen, and we play with expensive equipment.
I study mussels – the same ones you’ve sautéed in wine. On the outside, there isn’t much to them, but we all know it’s what’s on the inside that counts. And take it from me, they’re fascinating!
What I find particularly interesting is that they can live in salty, ocean water or nearly fresh, estuarine water. They can actually change how many amino acids (just like the ones we take in vitamins) they produce to prevent themselves from taking on so much water that they burst or from losing so much water that they shrivel and die. Pretty cool for something that doesn’t have a brain. This is no simple feat either; the task puts a fair amount of stress on the animal.
|Mussels image from NOAA Mussel Watch Program.|
When put into freshwater, mussels clamp up their shells, turn on and off genes, and start pumping those magical amino acids out of their cells until their entire bodies match the salt content of the water. So that brings me to what I study: how do they do it? What genes do they turn on? What happens to their cells when this salt-stress occurs? Spending all of my daylight hours pent up the lab helps me answer some of these questions.
Just like you and me, when faced with a stressful situation, mussels change how they act (so to speak) to cope with the stress. They make stress proteins, they stop growing, and they focus on survival. Some probably even stop sleeping.
But mussels are not created equal, and some are better at this than others. Some have no problem dealing with freshwater. How do I tell what sets them apart? For one, I grind up pieces of mussel tissue and look directly at the DNA. I can then tell if the DNA from one (or at least some of the genes) reacts differently when the salinity is lowered. I also look directly at the cells and look for changes. I’m still working on figuring out how it all works, but I at least get to take pretty pictures in the meantime.
|A microscopic image of mussel gill |
tissue magnified 2,600 times.
No problem for our super tough mussels, but what about the more sensitive ones? Will they die? Will they toughen up? Only time will tell, but maybe, just maybe, all of my hard work will give us a better guess at what will become of the precious, delectable mussel. And if you don’t buy any of that, just remember: happy mussels are tasty mussels.