11 October 2013
Rowley, Massachusetts

I’m standing in the sandy soil of Stackyard Road adjacent to the marsh of Clubhead Creek.  The day is overcast and the light wind makes it cool, but it’s still a nice day on the marsh in October with an air temperature of 18 C (60 F).  A white van arrives, bouncing in the tire-swallowing holes.  Mr. John Reynolds, a teacher at Ruppert Nock Middle School in Newburyport, emerges.  He’s thin and a young-looking 50.  His dark complexion signals that he spends a lot of time outside.  In fact, his teaching curriculum is centered on taking his students into the wilds of Essex County to explore the local ecosystems.  The students have been kayaking on rivers, biking to parks, and sitting in nature to listen, to watch, and to smell.  Today they are here to experience the living laboratory of the salt marsh.

Ten seventh-grade scientists of varied sizes emerge from the van and are joined by the Assistant Principal Ms. Lisa Furlong.  We get right to work.  These scientists are eager and excited to be outside.  Instead of smartphones, these students have field notebooks and pencils in their hands.  Instead of distractions, the students have questions.

We start with the first step of the scientific method:  observation.  They observe that the invasive reed Phragmites is found only near the upland edge or near the road and that most of the marsh is dominated by Spartina spp.  We move to the next step:  Hypothesis generation.  They hypothesize that soil salinity is driving these plant patterns, specifically, that Phragmites is limited by high soil salinities and that Phragmites soils will have lower salinities than the Spartina soils.  After a quick lesson on how to use a refractometer, we move on to the next step:  Hypothesis testing.  Two teams sample the marsh soils for salinity in the two plant zones.  The Phrag team is swallowed by the reeds and a member of the Spart team discovers that straight lines in the marsh mean leg-swallowing ditches.  They create data tables and convene to share their data.  The results?  Phragmites soil: ~32 parts per thousand (ppt), Spartina soils: ~45 ppt.  Hypothesis supported!  In fact, in general, Phragmites is limited in growth and expansion by higher soil salinities.  A more detailed study in the Parker River marshes by Mass Audubon can be found here.

Red blazes of sea-pickle streak the marsh.  It is a succulent, like a cactus, and after some rigorous coaxing (squeezing the heck out of it) we get some sea-pickle juice on the refractometer.  It has an internal salinity of 90 ppt (marine salt water is 32-35 ppt)!  That’s almost 10% salt!  You can learn more about why sea-pickle (also called pickleweed) is so salty here.

The eager young scientists are let loose on the marsh to find what life lies beneath the now brown, but still thick grass.  They combine their treasures in a box and we discuss what they had found in a scientific show and tell.  I kneel down next to the box on the ground and am surrounded by a forest of middle school students.  Mr. Reynolds and Ms. Furlong are pushed to the side, like the losers of a game of Duck-Duck Goose (does anyone play that anymore)?  The young scientists point to their individual treasures.  There’s the coffee bean snail, Melampus bidentatus, which is a pulmonate (air-breathing) and mostly terrestrial snail that is still connected to the sea by planktonic larvae.  Scribble of pencils on notebooks.  There are small wolf spiders.  The molt of the invasive green crab, Carcinus maenas.  More scribbling.  A field cricket (the males of which use their wings, NOT their legs, to make cricket calls to woo their ladies).  A ribbed mussel, Geukensia demissa which are not good to eat, unlike their cousins the blue mussel.  Scribble. And now zombie amphipods.  Amphipods (also called marsh hoppers) are normally brown, but orange amphipods are parasitized with a trematode that changes their behavior and makes them exhibit risky behavior so they can be eaten by birds (the bird is the final host of the parasite life cycle).

I open the trunk of my Honda Civic for larger and possibly more charismatic critters of the marsh.  I pull out several horseshoe crab molts, including a large female the size of a hubcab and reported to have been at least 25 years old.  The scribbling is abandoned for tactile experiences.  I pass around the molts and let the students touch the lacquered, large female.  The students learn how to tell the difference between males (the ‘boxing glove’) and females and that sexually maturity occurs when they are at least 9-11 years old.  And why the male has ‘boxing glove’ claws (to hold on to the female for mating).  I tell them about the blue blood of these crabs and how it’s important to our own health (more on this later).

For the final act I pull two unhappy, but alive lobsters from a brown paper sack.  I teach them how to tell the male from females (I teach the students, not the lobsters – I think the lobsters already know) and the function of their different claws (one is a cutter and one is a crusher).  More tactile experiences as the lobsters are passed around.  Now when they play with their food they will do it with knowledge!  And the phones finally come out.  Pictures taken, posted and tweeted to the field notebook of the world.

I am excited by the enthusiasm of these young investigators.  I mean, isn’t that why I do science, because it’s cool?

The tide has risen to edge of the road, another cycle completing.  The students give their thanks and climb into the white van.  Handshakes and thanks are exchanged between me and the Ruppert Nock Middle School teachers.  And then we drive and bounce down the pocked road of Stackyard and reflect on what we all had just learned.

– David

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.

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 a line of scarlet as the pickleweed has occupied last year’s path.

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 squeezed 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.

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 it 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 lose its 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.

A version of this blog first appeared on New Leaf.

by David

Cowlicks of Spartina patens, Rowley, 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: cowlicks.  The flat marsh is punctuated with tufts of marsh grass that lean against each other in swirls like the cowlicks of hair of a little boy who just woke up.  These are the cowlicks of Spartina patens.

According to Dr. Scott Warren, a ‘retired’ plant physiologist now retired from Connecticut College and TIDE Project principal investigator, these cowlicks 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 cowlicks.  The slight vagaries in elevation, stem density, and wind create those patterns.”  And these cowlicks don’t appear until the end of July because that’s when the plants are tall enough to be pushed over.

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 cowlicks, 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.  Chris Haight, a TIDE alum now in graduate school at Columbia University writes more about haying here.

The cowlicks 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.

Note:  a version of this blog first appeared on the New Leaf blog, written by yours truly.  And yes, I know it’s September so I’m a little late with this one.

– David

Eight short weeks ago I arrived at the Marshview Farm House, my home for the summer.

I would like to think that during the past eight weeks I, along with the other interns, have conquered the marsh. We have been stuck in mud up to our belt buckles; we have been swarmed by armies of no see-ems and greenheads, and we have participated in flume netting at midnight under the full moon. We have spent countless hours measuring fish, weighing plants, and analyzing data. Throughout this process, I have gained a wealth of knowledge, along with valuable experience in both the field and the lab.

My name is David Behringer and I am a rising senior at Washington & Jefferson College, in Washington PA. Although I am still trying to figure some things out, I plan on attending graduate school to earn a degree in fisheries management/biology. This summer I have been working closely with fellow intern Nate Andrews on Dr. James Nelson’s project.

Our focus has been on the demographics of the salt marsh creeks, the diet of the mummichog, and we have also been using length frequency analysis (LFA) to look at growth rates of the mummichog, Fundulus heteroclitus.

Right now we have been working on taking the gut content of the mummichogs to determine their diet. We start by removing the fish’s stomach. Then, using a probe, we gently slide all of the stomach’s content out. Once it has all been removed, we separate the content into detritus/ plant matter and protein using a dissection microscope. The protein and detritus are put in the drying oven and weighed separately. Using this method we are able to determine what percentage of the mummichogs’ diet is protein and detritus, respectively.

Although I was aware that mummichogs are opportunistic omnivores, I was shocked to discover how widespread their diet truly is. These little fish, ranging from 40-80mm, eat almost anything including shrimp, snails, mosquitoes, greenheads, smaller fish, and algae.

And for those of you who are still wondering about the title…

There are approximately 1,790,590 nitrate pellets in each bag of fertilizer. So with some quick math…

1,790,590 pellets

x 616 bags of fertilizer (50 lbs each)

= 1,103,003,440 is the estimated number of fertilizer pellets that we have put into the marsh this summer. Pretty Crazy!

Signing out!

David Behringer

Howdy folks. My name is Marshall Strong, and I’m here at the TIDE Project on behalf of Dr. Sallie Sheldon, from Middlebury College. For several years, Sallie and her interns have been investigating the filamentous algae which grows on the creek walls to see if there’s any difference in growth between the fertilized and the unfertilized creeks. Our current technique involves using bridal veil as an artificial substrate for the algae to grow on. We use a terribly high-tech device (a typical kitchen cheese-slicer) to scrape the existing algae off of a section of the wall and use drywall screws to screw the bridal veil into the mud, then wait for the algae to colonize it. In past years, we’ve found no significant difference between the fertilized and unfertilized creeks, which has been a bit of a surprise, so this year we’ve added exclosures around our bridal veil to try to control for the possibility that something may be eating the algae. The bridal veil squares have been out for a few weeks now, so we’ll hopefully get some data when we collect them at the end of this week and we can start coming up with some answers.

In the meantime, while I wait for my algae to grow, I’ve been taking a look at the pannes surrounding the creeks. There seems to be some debate over what exactly a panne is – a low-lying area of the marsh with different vegetation, or an actual pond in the middle of the marsh. For my purposes, I’ve been just looking at the ponds. Unlike the rest of the marsh, the pannes aren’t affected by the tides on a day-to-day basis, making them a bit of an anomaly. They get flooded with the rest of the high marsh every spring tide, but the rest of the month they just sort of do their own thing. I was interested in how the water chemistry changes over the course of one of these tide cycles, so I identified six pannes at both Sweeny and West of various sizes, and went to work taking some measurements. I’ve been out multiple times a week with a YSI the past month, taking temperature, dissolved oxygen, nitrogen, pH, and salinity readings. It’s still very much a work in progress, but there seem to be some trends in at least the pH of the pannes. More results soon to follow!

In other news, the spring tide was this weekend, which means late-night flume night sessions for all of us here at Marshview (with the exception of yours truly, who managed to pass out on a couch before sampling occurred last night!). We did Clubhead and West Saturday night, and Jimmy did his very best to scare the pants off of us all as we emerged from the woods. Caitlin and I got a bit jumpy, but Nate was convinced a coyote was about to end him. We all went out to Sweeny and Nelson this morning to collect our fishy harvest, which will keep Nate and David busy for the rest of the week, as well as our high schoolers and anyone else with some free time on their hands.

In addition to spring tide, the end of the month has brought some welcome relief from the insect population. I don’t want to jinx it, but I didn’t have to swat a single greenhead on the marsh today! That’s not to say I got off scot-free – the greenheads who managed to colonize our boat are intrepid little biters, and seem to have survived the spring tide. In any case, the next few weeks should be gorgeous and insect free. The TSA is blooming, there are pretty little blue flowers all over the marsh (no clue what it’s called, I’m no botanist), the dripper is dripping, and the bugs are all dropping dead. I’ve got another three weeks here at marsh view before I jet off to Copenhagen for a semester abroad. Looking forward to some data analysis in the near future!

Marshall… Marshall… Marshall…

Hey everyone!  My name is Caitlin and I am mainly focusing on Tall Spartina Alterniflora (TSA) for the TIDE project.  More specifically, I am looking at its growth in both the fertilized and the unfertilized creeks by cutting and collecting plants from two small plots, known as clip plots, at each of three set point, known as transects, along creeks each month.  Each plot is taken from two set elevations at each transect, one lower and one higher, across all of the creeks in order to standardize the water coverage at each plot.  Unfortunately, some of the creeks did not want to cooperate and finding plots with the right depth of water coverage and a large enough plot of TSA proved to be harder than it sounded.  In order to determine depth of the water, we not only had to measure the distance from the high marsh to the mud in which the TSA was growing, but we also had to put out 108 tide sticks to measure the water level at high tide.  These sticks were homemade with Phragmites, an invasive reed we cut down in the backyard with a machete, and were pained with glue dyed with food coloring.

Despite a lot of rain, I was able to collect my first set of clip plots with help from all of the TIDE researchers here at Marshview during the last few days of June.  Once I brought the samples back to the lab, I washed the mud off of each plant and out of the crevices of the leaves and then froze them.  While this wash process is tedious, it ensures that the mud will not get into any of the lab equipment while I take measurements.  In the coming weeks, while I wait for the plants on the marsh to grow taller and for my next clip plot date in late July, I will be processing the plants here.  In addition to looking at stem density, leaf counts and plant height, I will be taking leaf area measurements to gain further insight on the growth of the plants in each of the creeks.

When I am not working with the TSA, I am working on other portions of the TIDE project that have been introduced in previous posts.  Some days I help Nate and David count and measure fish, others I go out with Marshall to work with salt pans.  Yesterday I went out with Belle to take routine nutrient samples and to try to obtain larvae in Plankton nets.  Today we collected mud cores to test for benthic chlorophyll levels for the month of July, then I helped Nate and David look at the gut contents of mummichogs.  As for the rest of the summer, only the tide will tell.