Tag Archives: Salt marsh

The winter sculptress

January 2015, Eastern Virginia

Ice covered marsh elder - Yorktown, VA, Jan 2015 (1)

The icy fog of winter swallows the Mid-Atlantic. The temperatures drop below freezing and weld the fog to all that it touches. Everything – limbs, leaves, porch steps, 1999 Honda Civics – are glazed with an 1/8 inch rime. Were I snail and one who could skate, I would don my snail sweater and skate (having only the one foot) and invite all my snail-skating gastropod-friends to my front steps and glide from one rail to another. Limbs sag heavy under the new weight. I – not wanting to skate on my steps – grab the rail. It too is slick with the icy slobber of a winter fog – and hold both my breath and myself as best I can. Winter redeems itself as an artist – the world now a garden of ice sculptures.

I scrape ice from my windshield with an bottle because apparently owning an ice scraper is much too much of a luxury. THe holes I make in the ice likely are not street legal as most of my view still obscured, but I take my chances and drive of to admire winter’s artistry.

Ice covered marsh elder - Yorktown, VA, Jan 2015 (3)

Of course I stop in the marsh. That is what you do when every surface you touch is lacquered with ice. Here in Virginia the Spartina stems – though dulled and browned with age – still stand. Today they glisten. Each leaf, each stem encased in a crystalline sheath. One that is cracked like, but intact. Like a mosaic of glass pebbles – each magnifying the beauty of which it clings. On the bushy marsh elder, each leaf is a glassy pendant.

Ice-covered Spartina - Yorktown, VA, Jan 2015 (2)

Ice covered marsh elder - Yorktown, VA, Jan 2015 (3)

My hands, without any sheath – glove or ice or otherwise – beg me back to the car. From the comfort of a defroster I admire what is now an icy meadow of marsh. By the weekend, the 50 degree temperatures will strip away the artistry of winter, each glassy sculpture losing its luster yielding to the rough concrete texture of winter’s true self.

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A unicorn in the marsh

A fiddler crab, tee hee
A rare species of fiddler crab

In the Great Marsh, he should be a myth, like a unicorn. But there he is. Like a nervous cuckoo clock in the mud, he pops out two or three times before he completely shows himself. A male fiddler crab (Uca pugnax), with a blue burnish to his shell and the characteristic obscenely large claw. I am astonished to see him. Astonished because I am probably the first person to see a fiddler crab pop out of the Great Marsh mud.

The Great Marsh stretches like a verdant yawn in the Gulf of Maine, which is the whole of the ocean from Nova Scotia to Cape Cod. Here the salty waters are chilled by the Labrador Current, a river of sub-arctic seawater that is born between Canada and Greenland and plunges south like a fist. The warmer waters from the south are deflected off the flexed arm of Cape Cod and kept out of the Gulf of Maine by the colder waters of the Labrador Current. As my New Englander friends like to brag, particularly when the snow is deep and the wind biting, this is a place only for the hardiest of souls.

Ovigerous (egg-bearing) fiddler crab, Uca pugnax, caught in a Rowley, Massachusetts, salt marsh
Ovigerous (egg-bearing) fiddler crab, Uca pugnax, caught in a Rowley, Massachusetts, salt marsh. Credit: Ashley Bulseco-McKim

Fiddler crabs are a warm-water species preferring the temperate waters south of Cape Cod. I am of the same opinion. I can snorkel in swim trunks in Buzzards Bay in July, which is on the south side of Cape Cod, but when I try to do the same on Cape Anne and its rocky shores, it’s like an ice cream headache for my entire body. I, too, am a warm-water species.

I search the mudbanks for other crabs, but find only him. Maybe he is a unicorn. An accident of currents and luck. Then I search other tidal creeks. Jericho, West, Clubhead, Nelson. Though their numbers are low, I find more fiddlers. Their burrows, only as wide as my thumbnail, perforate high in the mudbanks near the hairline of the Spartina grass. Many burrows are abandoned. Active burrows are identified by what look like chocolate ice-cream sprinkles – what we locally call ‘jimmies’ – scattered around the burrow entrance. These are fecal pellets from a recently fed crab. A quick probe with my finger (a very scientific technique, I assure you) confirms the fiddler’s residency.

I search beyond the Rowley marshes and find more fiddlers. Directly behind J.T. Farnhams’ in Essex. Off Atlantic Avenue in Gloucester. Chubb’s Point in Manchester-by-the-Sea. Next to the Endicott Square Shopping Plaza in Danvers. Massachusetts indeed has a new resident. So does New Hampshire as the fiddlers have journeyed as far north as Hampton.

Salt marsh fiddler crab, Uca pugnax, Manchester-by-the-Sea, Massachusetts
Salt marsh fiddler crab, Uca pugnax, Manchester-by-the-Sea, Massachusetts. Credit: Jon Whitcomb

How can a warm-water crab invade the province of the cold, a place where it has never before been able to survive? The answer lies in the fact that the province of the cold is becoming warmer. As the climate warms, so too does the ocean as the overburdened atmosphere gives some of its heat to the ocean to hold, an arrangement as old as the Earth. In the summers of 2012 and 2013 the Gulf of Maine waters warmed to 68 degrees Fahrenheit from the typical and chillier 63 degrees of years prior.

Those five degrees may not mean much to those of us who can adjust thermostats, but those five degrees are significant to an animal that uses the environment to regulate its temperature. For fiddler crabs, those five degrees are the difference between scuttling across the marsh and an arctic death.

Fiddler crabs did not arrive in the Great Marsh in the form that we recognize them, with their snapping claws and rounded bodies. They instead arrived as larvae carried by the currents and tides. The larvae are mostly heads, translucent triangles with Pinocchio noses and topped with a single spine, with legs and tails dangling. For fiddler-crab larvae, 64 is the key that unlocks the Gulf of Maine. Below that number in degrees Fahrenheit and these drifting triangles do not metamorphose into the crabs that make thumbnail sized burrows in the marsh. But give that number a degree or five, and those once-thought unicorns of the Great Marsh become a reality.

And so, borne on the currents of climate change, the fiddlers have made a surreptitious arrival to the Gulf of Maine and the Great Marsh.

The consequences of this incipient colony are unknown. As burrowers, fiddler crabs are engineers that re-work the soil and the marsh chemistry. If the effect is positive or negative is not yet known. I can only give you the answer that is common given by scientists that can be utterly frustrating:

It depends.

Too many crabs and the marsh grass cannot establish, which may ultimately lead to marsh loss. Only a few crabs and the marsh grass grows better. What I can tell you for certain is that with the arrival of these new colonists, just as when we arrived in the 1600’s, the Gulf of Maine and the Great Marsh will be changed forever.

Already we have seen marine species such as lobster, flounder and hake shift northward as a result of climate change. Some, however, still consider climate change a myth, like the unicorn. But sometimes seeing is believing. Like a fiddler crab in the Great Marsh.

The science is here: Fiddler on the Roof: A northern range extension for the marsh fiddler crab Uca pugnax

And the winner is…

Galloping hordes of marsh snails!
Galloping hordes of marsh snails!

I have just returned from the New England Estuarine Research Society meeting in Groton, Connecticut (don’t be jealous). One of my students, Bethany Williams, gave a talk on the coffee-bean snail, Melampus bidentatus, and the effect of sea-level rise. I don’t want to give any spoilers, but as the salt hay in the Great Marsh is lost as sea-level rises, it could be bad news for the snail. But in sunnier news, Bethany, an undergraduate from Florida State University, gave her first talk ever and won best Undergraduate Oral Presentation! Very exciting! Congratulations Bethany!

Bethany's first scientific talk, NEERS, Rankin Prize Winner (11)

Below is time-lapse video of snails moving in and out of an abandoned footpath in the marsh. It demonstrates how snails avoid the path during the daytime heat, but when the temperature lowers and the humidity rises they gallop out from the grass to gobble the algae in the open. When the sun (and the heat) returns they ebb back into the grass. It’s a cool video that demonstrates potential impacts of climate change on these, turns out, sensitive snails. When Bethany’s thesis is complete, we’ll post more of the story. For now, enjoy the video.

You must be ‘shroomin: sea-level rise and ‘shrooms

Sulphur shelf mushroom (Laetiporus sulphureus), Rowley, Massachusetts

18 November 2013
Rowley, Massachusetts

Forest edge, overlooking the marsh
It looks like the arm of a colossus, but it turns out to be the giant’s head.  The ground must have shook when it fell.  The top of the large northern red oak (Quercus rubra) has snapped off and now decapitated, stands only 30 feet tall.  Two of the giant’s limbs have been sheared from its body.  What has slain this giant?

From where the limbs were once attached I see a giant ruffle of dingy-white to yellowish shelf mushrooms.  These are certainly devouring the tree from the inside. 

Mushrooms are the fruiting bodies of fungi (a kingdom of life more closely related to you and me than to the red oak).  The white and yellow shelf I see is simply the tip of the fungal iceberg.  Beneath the bark is a large spreading network of threadlike hyphae – rootlike structures that collect water, nutrients and release wood-dissolving enzymes.  This fungal filigree is now slowly gutting the tree.

I need a closer look, because I’m a blanking scientist and this is what we do.  Red oaks, however, don’t like scientists climbing on them because they have this pesky habit of not having any David-reachable limbs.  I find a rope in my car and throw it over the lowest limb, which is 20 feet up.  I’m a lightweight at 140 lbs, but pulling myself straight up is just as embarrassing an effort as it was with my pipe-cleaner arms in gym class.  I take off my shoes for better footing and ‘walk’ up the trunk. 

On the third try I get to the lowest limb and then hang there in the air, my legs desperate to touch something.  I swing my legs trying to get one onto the limb.  After much cussing and grunting, I am on top of the limb.  I will feel this tomorrow.

The mushroom has a mushroom smell, a pungency of sweetly soured earth.  I don’t know what it is but I collect a sample for later in case it’s edible.  This mushroom is killing the tree, but I don’t think it’s the first agent of death. 

At the foot of the tree, there where my shoes are, is seaside goldenrod (Solidago sempervirens).  Nearby is rough cordgrass (Spartina pectinata) and marsh elder (Iva fructescens).  These are salt marsh species.  Species that are invading the forest.

The phalanx of a rising sea besieges the bastions of the forest edge, felling these giant reds to open up the sky so that the army of marsh grasses can march inland.  The mushrooms are a secondary attack, entering the tree where it was wounded as the salt sapped the oak’s strength and stripped its limbs and toppled its canopy.  All along the leading edge of the marsh, other giants have been felled, their carcasses abloom with feasting fungal scavengers.  In 20 years, there will be nothing in this spot to climb but 6-foot tall marsh grass.

The advancing sea is advancing faster these days.  In the past decade, sea-level has risen  6 centimeter in the area at a rate of 6 mm/year (compared to an average rate of 3 mm/year in the previous 90 years). (I explain below how I arrived at this number). The battle between the forest and marsh is lost and won in the length of a pinky.  The marsh doesn’t invade because of greed or ruthlessness, it invades to survive.

Like humans, moving to higher ground is a strategy to survive rising waters.  This is called ‘marsh transgression’ or ‘marsh migration’ and with accelerated sea-level rise, the marsh needs to migrate landward quickly.  In areas where the land is too steep to climb or where there is a backyard wall or a road through a marsh, the marsh will throw itself against the land and the wall desperately as the water rises, like the non-believers against the doors of Noah’s Ark.

For now, this red oak still stands, its insides being dissolved by an unassuming sulfur ruffle of mushrooms.  The sea will continue to encircle its base until it pulls both the tree and mushrooms to the ground and the marsh over-runs it.  The mushroom, like the marsh, will simply move on to the next tree, following the advancing wave of a rising sea.    

Post-script
Dr. David Hibbet, a mycologist (and a fun guy – I couldn’t help myself!) at Clark University helped me identify the mushroom as a sulfur shelf (Laetiporus sulphureus), also known as, “chicken of the woods.”  He, and field guides, say it’s edible.  On the phone he said, “Some people can eat it no problem, but for some it causes severe intestinal distress.  I wouldn’t give it to anyone really young or really old.”  I’m 37 and just been diagnosed with irritable bowel syndrome so I thought I’d take a chance.  For science!

The flavor was astringent and bitter.  My taste buds said, “Spit it out!” but my brain said, “This is for science!”  I chewed for a bit and it had the texture of chewed, crumbled paper in my mouth (I used to chew paper as a kid).  My friend Brita said, “I eat it all the time!  But I sautee it and it’s good.”  Now she tells me.  I’m now three hours in and I feel fine.  But if I suffer from ‘severe intestinal distress’ later then I don’t know if I should blame the chicken of the woods or the IBS.

Helpful resources:

http://www.mushroomobserver.org – this is a crowd-source to identify mushrooms.

Field Guide to Common Macrofungus in Eastern Forests and Their Ecosystem Functions – United States Department of Agriculture. 

Duley Crabbe, my great friend who is also great at coming up with terms of battle and then patiently explaining what they mean – more than once.  Thanks man!

How to calculate sea-level rise from your very own home!

The National Oceanographic and Atmospheric Administration monitors tide gauges all along our coasts (as far back as the late 1800’s!, your tax dollars at work).
-Go to this website http://tidesandcurrents.noaa.gov/ and select a state and then select a tide gauge (I picked Boston because that’s closet to me).
-Then select ‘water levels’.  You’ll get a high tide low tide chart.
-Scroll down and select a year range (I picked 1921-2013).
-Select ‘meters’
-Select ‘data only.’
-Okay, this part is stupid, but NOW set the interval to ‘month’ after it gives you the “Error: Range Limit Exceeded: The size limit for data retrieval for this product is 31 days” message (if you know a better way to do this, let me know!).
-Select ‘Export to CSV’ and you’ll get an Excel file.
-In Excel you’ll have this wonderful raw data set!  Now what to do with it?  I use pivot tables.  Don’t know how to use pivot tables?  Learn.  They will save your life when working with big data sets.  I averaged Mean Sea Level (MSL) by year and plotted MSL by year.  You can get the sea-level rise (SLR) by year by adding a linear trend line and looking at the linear equation.  The number before the x is your rate of change per year, or in this case the rate of sea-level rise.  Remember that this number is reported in meters so 0.003 m = 3 mm.  You can look at different chunks of times to see the rate of sea-level rise accelerating in the past few decades.  Have fun!

Pickleweed

Saltmarsh Pickleweed, Salicornia europaea, in fall colors in Rowley, Massachusetts
Saltmarsh Pickleweed, Salicornia europaea, in fall colors at high tide in Rowley, Massachusetts

The week of 21 September 2013
Rowley, Massachusetts
I step onto the marsh and it announces autumn.  Before the leaves of the trees are set afire with an autumnal blaze, before the morning air is tart with a cold bite, scarlet forests of pickleweed are the first to foretell fall’s approach.  

I’m standing in the middle of a scarlet forest that extends for meters in either direction but stops abruptly against the taller Spartina alterniflora.  Among the golden buttery straw of Spartina I see small flare-ups of scarlet picklweed here and there.  The haphazardness of these patches is interesting in this salt marsh, because it has strict patterns of vegetation governed by the tides and competition among species.  The scarlet adds a color mosaic to an otherwise monotone palette.  The randomness of color is inspired by the gypsy lifestyle that the pickleweed has adopted.  It is a gypsy of populations, not necessarily individuals.  Individuals have one season to grow, reproduce, and die, making them annual plants (vs. perennials which persist for more than one year).  Its shallow root system and short stature (~20 cm) make it a weak competitor, thus it must be able to move on a whim as a population if overrun by superior competitors.  To survive on the marsh the pickleweeds must be opportunistic.  It is often found in areas where vegetation has been killed by disturbance or stress.  This most often happens when wrack – mats of dead vegetation that are carried by the tides – lays on top of living vegetation and smothers it.  The vegetation dies and the wrack is carried off by a spring tide (maybe weeks or months later), leaving behind a bare spot in the marsh.  For years, large swaths of wrack sat on this marsh, pushed against the levee that is the road by winds and tides, and smothered the marsh.  Some of the wrack is now gone and within a season half of the bare patch is colonized by picklweed.  This large stand of pickleweed may hold this spot for two years or more, until it is evicted by the deep-rooted and tall Spartinas that march across the marshscape.  The dots of pickleweed in the marsh are plants that squeezed in between Spartina neighbors where the canopy thinned and opened up, probably due to salt or flooding stress.  These gypsies are not picky where they settle; they know they won’t be there for long.

Wrack smothering marsh grass. As the tide lifts it off, it will leave behind a bare spot.
Wrack smothering marsh grass. As the tide lifts it off, it will leave behind a bare spot.

On another marsh, the foot of the scientist is the disturbance.  Each year a path is established to get to sampling locations and each year the path is moved to minimize footfall impact.  Now this year’s bare path runs parallel to line of scarlet as the pickleweed have occupied last year’s path.

This year's footpath paralleled by last year's, which is occupied by a line of scarlet pickleweed. This year’s footpath paralleled by last year’s, which is occupied by a line of scarlet pickleweed.

I kneel down and squeeze a fleshy finger of pickleweed.  It’s succulent. Succulence is a strategy used by plants to deal with low soil-water potential, that is, it’s hard to get the water out of the soil.  This happens in habitats where the soil water has a high salt concentration when there is infrequent rain (deserts; think cacti) or inundation by salty water (salt marshes and mangroves).  To increase the plant’s water potential (i.e., the potential of water moving into the plants) it increases osmotic pressure in its favor by storing salts in its cells.  This makes the plant saltier than the soil.  As we know with osmosis, water moves from areas of low salt concentration to high salt concentrations.** During a visit to the marshes of Barn Island, Connecticut , my friend Dr. Scott Warren demonstrated the plant’s osmotic strategy.  He squeezed the juice from a pickleweed onto a refractometer.  90 parts per thousand (ppt)!  Almost 10% salt!****  He pulled out a pocket knife, cut out a bit of marsh turf and squeeze it onto the refractometer.  55 ppt!  Aha!  So now the plant is able to pump water from the soil to plant passively via osmosis!  For reference, marine salt water is ~32-35 ppt.   

A forest of pickleweed
A forest of pickleweed

High salt concentration can disrupt cell function and kill you.  Here again, the gypsies are clever to prevent a briny death.  One feature that defines a plant as a plant is the presence of a large central vacuole in the cell.  These vacuoles are like large storage trunks separated from the cytoplasm and other organelles by a plasma membrane.  Plants shove all kinds of things into these cellular trunks and pickleweed stuffs its vacuole with sodium ions.  The cell is protected because the salts are safely stuffed into the salty trunk.

It is the saltiness of these cellular trunks that I am currently drawn to now.  I pluck a scarlet finger of pickleweed I bite into it.  It is soft, but firm and gives a slight crunch, which is why it’s sometimes called ‘glasswort’.  It’s salty but nothing that excites my taste buds.  Locals tell me people eat on salads but I’ll be damned if I’ve met anyone who has actually done that.  The wise internet tells me it is sometimes pickled in Great Britain (perhaps where the name ‘pickleweed’ comes from?). 

But tell me pickleweed, why the red?  You’ve abandoned your green because you’re breaking down the sun-harvesting chlorophyll as you begin to senesce.  You are winterizing.  But why the reds?  The reds come from your production of a class of pigments called anthocyanins, which come at an energetic cost.  Why spend the energy to make these pigments when you’re nearly dead?  Maybe you are signaling to grazers – perhaps a hungry salad-eater who needs a salty crunch –  that you should be eaten so that your seeds can be carried away?   

The pickleweed gives me no clues to this mystery.  Perhaps one of you out there know better.  

I pluck another red finger, which has many joints called nodes, and break the finger at one of those nodes.  It snaps and reveals two white circles.  Seeds.  The plant will soon loose it’s succulence, desiccate and release its seeds.  The seeds are the true gypsy form and they will caravan on the tides until they find their own one inch of marsh soil to call home next year.

**This is why you can kill a snail with salt; the water from the snail’s body exits its body wall to the saltier environment.  I can’t believe you did this you heartless bastard.  Didn’t you even hear him scream?

****I originally reported this at “almost 1% salt!” because I apparently can’t do math.

The cow licks of the marsh

The marshes of the Rowley River, Massachusetts

Near the final curtain of every July in the marsh, just as the greenhead swarms abate and the swelter of real summer has a final push, emerges a new character on the scene: cow licks.  The flat marsh is punctuated with tufts of marsh grass that lean against each other in swirls like the cow licks of hair of a little boy who just woke up.  These are the cow licks of Spartina patens.

According to Dr. Scott Warren, a groovy plant physiologist now retired from Connecticut College, these cow licks form because “…patens has a weak joint at the base of the stem and when the tides come in they push the plants over.  Some are laid flat, but sometimes they lean against each other and find support, creating cow licks.  The slight vagaries in elevation, stem density, and wind create those patterns.”  And these cow licks don’t appear until the end of July because that’s when the plants are tall enough to be pushed over.

Scott Warren holding class in the marshes of Rowley, Massachusetts
Though retired, Scott Warren, still holds class in the marshes of Rowley, Massachusetts for a set of interns in 2013

Spartina patens is a soft, high marsh plant and it’s uncertain what the benefit of being a push-over to the plant is.  If you consider patens resident saltmarsh cousin, Spartina alterniflora, it is rigid and not typically pushed over by the tides.  In fact, many of the Spartina’s (Spartina alterniflora, Spartina cynosuroides, Spartina pectinata), have stiff reed-like stems, whereas patens does not.  Why be such a softy and a pushover? 

While the benefit to the plant is unclear to me (your hypotheses are welcome in the comments section), there are clear benefits to the animals.  When patens lays down or cow licks, it’s still attached to the sediment.  At summer’s final bow and fall’s flourish here in New England, the aboveground portion dies but remains attached to the ground.  In doing so, it is able to overwinter and form a layer of thatch on the ground.  In the winter, this thatch acts as insulation to protect overwintering surface invertebrates such as snails that huddle around clumps of patens.  In the summer, this thatch retains moisture from the infrequently flooding tides and provides a refuge of surface invertebrates from the heat and dryness of the sun.  Should you like, you can watch a bare patch of marsh in the morning and watch snails run back into the protection of patens as the water-robbing sun rises in the morning.  The thatch remains 2-3 years, and is replaced annually.    

Spartina patens benefits two-legged animals not only via lush landscapes, but also by providing hay.  The softness of patens and its position on the high marsh make it attractive to hayers.  In fact, it’s common name is ‘salt marsh hay.’  In August, after the flooding spring tides, patens is cut, dried, baled and sold.  Just like the colonists did, except with tractors.  You can read more about haying here.

The cow licks of Spartina patens herald a more comfortable time in the marsh when the biting bugs are largely gone and the heat begins to lessen.  A time when the seemingly sleepy marsh continues to lull the eye with its sweeping lushness and invites a moment to pause and wonder.