Tag Archives: Salt marsh

How to survive winter

41 degrees Fahrenheit
You’re naked. In a salt marsh. With a giant rock on your back. It’s 41 degrees Fahrenheit. A cold that kills comes tonight. You see someone else. They’re naked. In a salt marsh. With a giant rock on their back. They’re covered in a slimy goop that is sticky and slippery at the same time. They have tentacles on their head. That’s weird. Then you remember, “Oh yeah. I’m a snail.”

As a snail, you are cold-blooded (the scientific term is ectotherm), meaning that you can’t regulate your body temperature internally like those uppity warm-blooded animals (endotherms) like mammals and birds. Your outside temperature is your inside temperature. What happens when the temperature drops below freezing? How do you survive if you are no warmer than an icicle?

38 degrees Fahrenheit
Head south to overwinter in Mexico or the American south like the monarch butterflies, green-darner dragonflies, and not-so-hardy New Englanders? No, you are a slow-footed gastropod and travel only as far as the nearest plant.

36 degrees Fahrenheit
Bury yourself under leaves, moss and the soft soil like the forest and garden snails? There is no moss here. And the leaves are few and the mud is as soft as a cinder block.

Other snails join you at the plant. You all huddle into a cuddle puddle.

34 degrees Fahrenheit
Hibernate like a bear in a cave? Marshes, by their geologic definition of having no rock from which to carve a cave, have no caves. Some snails, if lucky, sneak into crab burrows and stowaway in a muddy hibernaculum. But the holes are few and the snails are many. And a burrow is just a hole and holes are cold.

Your heartbeats slow. 

33 degrees Fahrenheit
Fill your blood with antifreeze like some insects? That’s not a trick you can pull off. But you must do something because cold kills. It’s not the cold itself that kills, it’s the stiletto-sharp ice crystals that form inside your cells. Crystals shred the cell’s membrane and the nucleus and mitochondria spill out like guts from a disemboweled goat. A cell freezing is like stabbing a water balloon with a hundred toothpicks from the inside. Frozen cells die. Freeze enough cells and you die. Winter will kill you.

Or will it?       

32 degrees Fahrenheit
Parts of your body start to freeze.

30 degrees Fahrenheit
The water in your body continues to freeze. But not the water inside your cells, the water outside your cells. The water between the cells. Because of osmosis, this pulls water out of your cells, which makes them saltier. Salty cells, like salted roads, lower the freezing point of water and do not freeze.

22 degrees Fahrenheit
It’s midnight. You heart has nearly stopped. Parts of your body have frozen, but your cells have not. You will survive another winter. But you will still be naked, carrying a big rock, and covered in goopy slime.

It could be worse; you could have a fish living inside your anus.  

 

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Saltmarsh periwinkles, Littoraria irrorata, huddled against the stem of needlerush (Juncus romerianus) in Yorktown, Virginia
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Snails huddling for warmth. The smaller snails in the foreground are coffee-bean snails (Melampus bidentatus). The larger snails in the background are periwinkles (Littoraria irrorata)
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Saltmarsh periwinkles, Littoraria irrorata, huddled against stems of needlerush (Juncus romerianus) in Yorktown, Virginia
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A cute cuddle puddle of saltmarsh periwinkles (Littoraria irrorata)

Post-script
Many marine snails use this ‘freeze part of my body’ trick to survive the winter. The snails starring in this essay are the coffee-bean snail, Melampus bidentatus, and the marsh perwinkle, Littoraria irrorata.

Post-post-script
It’s not clear to me why the snails huddle together when it’s cold. I can come up with at least two hypotheses. First, snails huddle together to shelter each other from the wind. Second, they may not be seeking each other, but all seeking a plant to huddle against. Like humans at an airport. You’d like to avoid everyone, but you’re all drawn to the same place and have no choice but to huddle together and try to survive.

The Joker in the Salt Marsh

The Great Marsh, Massachusetts
For C & J.

On a recent sampling trip in the Great Marsh I brought along a new assistant, The Joker. He was done shooting his latest film and needed a break from his general villainy.

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The Joker investigates the mud between the stems.
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Like some new interns, The Joker was easily distracted. Here he mounts a steed, a horseshoe crab (Limulus polyphemus) molt, and wields a mighty blade of grass.
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Come on, Joker! Quit horseshoe-crabbing around and let’s get to work.
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The Joker couldn’t avoid villainy entirely as he tried to recruit a horde of coffee-bean snails (Melampus bidentatus) to join his evil gang of gastropods.
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He got one recruit. And it totally went to his head. 
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As one of the more fashionable villains, he fell in love with a blushing pickleweed (Salicornia europa) that matched his hair and jacket. 
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The Joker came across a ribbed mussel (Geukensia demissa)… 
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and decided he needed more mussel for his next bank heist. 

 

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The Joker learned the different marsh grasses. Here he’s showing a flowering shoot of marsh hay (Spartina patens) that it’s not the only grass in the marsh. 
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After he learned his grasses, we finally got to work. Here The Joker is estimating the percent cover of grass in the marsh. Looks like about 100%, don’t you think, Joker?
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After a while, I was able to trust him to record data. He was a little slow and a lot messy, but that’s field work sometimes.
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As we left the marsh through the woods, The Joker asked for a snack. I said no. 
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But we did have a well-deserved swim in the river.

Marsh beauties

It has been a busy summer for my lab. Here is a taste of the beauty that I get to see when I sample the marsh. Most of the pictures below are from the Great Marsh in Massachusetts unless stated otherwise. What a gorgeous ecosystem sparkling with life.

Sea Lavender, Limonium, Rowley, Massachusetts (5)
Sea lavender looking lovely (Limonium sp.)

Sea Lavender, Limonium, Rowley, Massachusetts (6)

Sea Lavender, Limonium, Rowley

Red mite party, West - May 2017 (3)
A shock of red mites meet on the marsh
Snail and eggs, Cushmans Landing (1)
I think these are fish eggs, not snail eggs (Virginia marsh).

 

Spartina patens - Rowley, Massachusetts
Salt hay (Spartina patens) in the sunset

 

Rowley House Sunrise, Rowley, Massachusetts
Good early morning Rowley River. I’m going back to bed. 
Barnacles on Spartina
Barnacles posing as dirt on the grass (Virginia marsh)

Plant bug on fiddler crab, Rowley, Massachusetts

A plant bug sits atop a muddy fiddler crab (female, Uca pugnax)

Crabs with Jeff Shields (12)
What the electric insides of a fiddler crab looks like (Uca pugnax)

 

 

 

Saltmarsh amphipod (Orchestia grillus) on a Spartina stem. Brown is the normal color morph, compare to the orange, parasitized morphs. Plum Island Estuary, Massachusetts

Amphipods: the new menacing marine menace?

This week a young man in Australia was attacked by something while he was swimming in the ocean. His legs were bloodied and covered with hundreds of small bites. At the hospital, doctors were baffled about what bloodied the young man’s legs. The dad – who rocks in this story – went back into the water with a bloody steak and collected the small, flea-like animals. They were identified as amphipods, which are small crustaceans. If Sharknado has taught us anything, a movie about flesh-eating amphipods can’t be far now. Let’s see what that movie trailer might look like.

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A young, beautiful mother sits on the beach and watches her charming son, who she can’t believe is growing up so fast, swim in the ocean. Gulls wheel overhead and waves roll gently. The sky blue.

Boy: Mom, watch me swim.
Mom: Okay.

[cue the Jaws-theme music rip-off]

Cello: Duh-nuh

 Boy: You watching?
Mom: Yes, dear.

Cello: Duh-nuh

 Cello: Duh-nuh

 [cue that voiceover guy]

 That Voiceover Guy: Just when you thought it was safe to go back into the water again.

 Cello: Duh-nuh, Duh-nuh, Duh-nuh, etc.

 The boy screams and grabs his leg. His mother runs into the waves and pulls him out. His legs are bleeding but there’s nothing on them. A handsome and rugged marine biologist who looks just a little bit dangerous but you know you’d feel safe in his arms, runs over.

Mom: What did this!?

 Ruggedly handsome marine biologist: They’re amphipods.

 Mom: Oh my go…wait, what the heck are amphipods?

 Director: CUT!!

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What the heck are amphipods? They are small crustaceans related to shrimp and crabs and lobsters. Typically, they aren’t larger than your thumbnail. If you’ve picked up seaweed on a beach, you’ve probably seen them. They are the small animals flipping and tumbling around like fleas. Those are amphipods. Sometimes called ‘sand fleas.’ Or ‘beach fleas.’ Or ‘beach hoppers.’ Or ‘sea fleas.’ The ‘flea’ name refers to the shape of their body (pressed from the sides) and the fact that they can flip around using their tails.

The media has used the term ‘sea lice’, but that really refers to an isopod, which can be parasitic on fish and look like the rolly-pollies (aka doodle-bugs) you find under logs.

Are amphipods the new marine menace? A pack of ravenous, flesh-eating beasts that roam the oceans looking for prey? Well, no. They do eat flesh, but typically not live flesh. We marine biologists (both the ruggedly handsome and other variety) don’t think of amphipods as predators but as scavengers that eat dead plants and animals. They’re more like tiny vultures swimming through the sea looking for something dead to stick their heads into rather than wild dogs looking to tear apart a baby deer.

I study amphipods in the salt marshes of Massachusetts and Louisiana (you can see pictures of them below). Just like on the beach, if you pick up seaweed in the marsh, hundreds of little crustaceans will flip and spring until they can hide in the grass. Not much of a terror. In terms of diet, these amphipods are more interested in a rotting veggie burger than a hunk of a marine-biologist.   

Then why did they attack the young man’s legs in Australia? We’re not sure. Amphipods can bite humans – sometimes beach runners will have a bite or two – but they have rarely caused such damage. The best guess is that the amphipods were in a feeding frenzy and the young man’s legs happened to get in the way.

While I’ve been playful with this story, as a father, I too would have been worried. As a marine biologist, I am curious. It shows that we still have a lot to learn. The next time I pick up an amphipod I will check to see if it’s wearing a handkerchief and holding a knife and fork.  

 

 

P.S. Now that we have flesh-eating amphipods in the news, soon I will write about zombie amphipods. Stay tuned. Duh-nuh…

P.P.S. If you enjoyed this article then please post it on Facebook, Twitter, or your favorite social media. And don’t forget to follow me. 

The vanity of fish and snails like underwater ants

A wonderful video taken in a salt marsh ditch in Newbury, Mass. The fish is who wants to make sure the camera gets his good side is the mummichog, Fundulus heteroclitus. For scale, the snails are the size of a BB from a BB gun. In all my time in the salt marsh, I’ve never seen so many! I guess I’ve got to stick my head underwater more often. Thanks to DeRosa Environmental for bringing the video to my attention.