TIDE Scientists inducted into AAAS – Part II

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From L to R: Jane Tucker, Anne Giblin, and Sam Kelsey
From L to R: Jane Tucker, Anne Giblin, and Sam Kelsey

Anne’s recent election into AAAS is well-deserved, and if there were a companion award for outstanding achievements in kindness, generosity, and commitment to others, she would rightfully be awarded that, too.   I have had the privilege of working closely with Anne for over 20 years, and I should know.

Anne Giblin “speaks” biogeochemistry, thermodynamics, biology, physical chemistry… really all the “hard” sciences…as a first language.  They seem to be part of her innate intelligence.     But she is not a desk scientist.   She loves to be in the lab, or even better, out in the field conducting experiments or collecting samples.   Adverse field conditions are her forte!    She is not stopped by freezing temperatures or clouds of mosquitoes on the North Slope of Alaska, nor by tropical heat, “no-see-ums” or scorpion stings in Panama.   She does not let little things like utter darkness in the cold depths of Adirondack lakes or a blanket of sewage sludge on the bottom of Boston Harbor dampen her enthusiasm for collecting more mud and adding dives to her SCUBA log.   She does not send her students or employees out to do this work for her….she jumps in first.   All of this to keep adding pieces to the puzzle of element cycling in sediments, particularly with respect to nitrogen, carbon, and her first love, sulfur.

Hard work is often matched by good cheer. A long day with the PIE-LTER team in the marsh at Plum Island, in itself fun, is routinely followed by a good meal (often prepared by Anne),   a good local brew (often provided by Anne), and good stories (often told by Anne).   Over the years, these days and stories and Anne’s optimism have become encapsulated by some memorable lines, now used affectionately by the team.  Three of the classics are:  “Done by noon!” (as in, “It won’t take long, we’ll be ….”), “That’s not thunder, those are jets!” (at next occurrence, accompanied by a bright flash of light) , and “No herics!” (i.e. heroics… I mentioned Anne’s first language is science, not English, didn’t I? It’s really the only thing I can help her with!).

Sure, Anne has the necessary stats on her CV that attest to her accomplishments as a scientist.  But the best testament of her success may be that, in an increasingly difficult funding climate, and at an all soft-money, independent research laboratory, Anne has kept herself and her team funded for over 25 years.  It is tribute to Anne as a mentor, colleague, and friend, that we have all wanted to stay.

Jane Tucker is a Research Assistant at the Marine Biological Laboratory.

TIDE Scientists inducted into AAAS

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This weekend, Dr. John Fleeger, a former TIDE Principal Investigator (PI), and Dr. Anne Giblin, a current TIDE PI are being inducted as a member of the American Association of the Advancement of Science (AAAS), known to us scientists as Triple-A S, because we’re too busy for real words.  AAAS is like the Hall of Fame for scientists and it’s a big deal.  We at the TIDE Project are incredibly proud of John and Anne’s accomplishment.  It is well-deserved.

In this post I will highlight John.  In the next, Anne.

I could list many of John’s accolades including his 150 publications in the scientific literature including topics from the Gulf of Mexico oil spill to carbon sequestration in the deep ocean to community ecology of very small crustacean in the dirty, dirty mud to studying the Plum Island marshes here on the TIDE Project.  I could highlight his wonderful teaching career at Louisiana State University spanning over 30 years.  But what I’d rather do is talk about John as a mentor.  My mentor, who guided me to my Ph.D.

John’s mentoring style can be summed up easily: his door was always literally open.  And no matter the crazy nattering that spewed from my lips, he looked at the floor while nodding and waiting for me to finish.  Then we would discuss.  He never said my ideas were stupid, though he gently said they needed more ‘development.’

And he was patient.  I can’t tell you how many times I heard him say without annoyance “Again David…” meaning that he already told what he was about to say and he was gently reminding me.

I appreciated how quickly he made comments on my scientific manuscripts.  Well, how quickly he massacred them.  My words were slain without mercy for their wrongness and their bodies littered the battlefield of my manuscript.  It frustrated me because I prided myself as an excellent writer.  But academic writing has its own style and language and John was teaching. Today I’m a better writer because of the time he took.

One Saturday morning in Baton Rouge I was at the scope sorting samples.  John came in with a draft of my research proposal that he massacred.  He asked me, “David, what are you trying to say here?”  Then before I had a chance to answer, he looked at the draft and said with rare exasperation, “Do you even know what you’re trying to say?”  I started to say something, but said, “Well no.”  And then he took the time to help me start over.

I still seek John’s advice today on my manuscripts.

The following is from the Acknowledgements of my dissertation:  “In 2003, the brave or foolhardy Dr. John Fleeger, with his nodding head and seemingly infinite patience that I tested more than once took in my independent and sometimes irascible spirit and navigated it down a tortuous, yet productive path.  I thank him for reading (and re-reading and re-reading) every word I’ve written as a graduate student, for swatting and cursing mosquitoes with me in the marsh, and for always having his door and mind open.”

Five years later, those words, unmassacred by John’s pen, still ring true.

Congratulations John.  Your induction into AAAS is well-deserved on many levels.

– David

David Samuel Johnson is a Principal Investigator on the TIDE Project.  A version of this blog post first appeared on David’s blog, New Leaf.

A student of the marsh

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There are so many stories of science from the Plum Island marshes and it’s wonderful when they are written down.  The one below is from Harriet Booth, a recent graduate of Brown University, who was also a TIDE Project intern working with me on the idea of a trophic bottleneck (that snails could gobble up a lot of energy and store it and choke off energy flow to fish).   And bless her heart, not only did she survive a summer in the boot-sucking mud and pain-in-the arm, face, and leg flies, but she went on to write an honors thesis.  Recently, she wrote a wonderful blog post about her experience, some of which is excerpted below.  I particularly like “…a small snail, muddy-colored and roughly the size of a peanut, emerged from the edge of the plastic, making a bid for freedom across the mudflat.”  I encourage you to read the entire essay here.

Harriet is currently a Research Fellow at the Atlantic Ecology Division of the EPA in Narragansett, RI.  She is looking at the effect of ocean acidification on bivalves.  Way to go, Harriet!

“The square, plastic quadrat slapped down where I tossed it, splattering me with little droplets of mud.  As I bent down to examine the sampling area, I noticed one side of the small quadrat seemed to be moving slightly, lifted by some tiny but determined force.  I looked closer and watched as a small snail, muddy-colored and roughly the size of a peanut, emerged from the edge of the plastic, making a bid for freedom across the mudflat.  I watched this little guy trundle resolutely away from me, making slow but steady progress across what must have seemed to him, a vast expanse of mud.  His tiny antenna occasionally appeared from beneath the front of his shell, wiggling about and seeming to wave at me as I crouched in the creekbed.  Eventually, I picked the snail up and placed him back inside the quadrat, counting the rest of the remaining snails at the same time.  However enjoyable it was to watch these little creatures bumble around, I had many more quadrats to toss before making my own escape out of the sucking mud of the salt marsh.”

David Samuel Johnson is a TIDE Project principal investigator from the Marine Biological Laboratory.  He writes about marshes at his New Leaf blog.

Acid plus middle school equals outreach

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Dr. Johnson is fixin' to learn you some chemistry!
Dr. Johnson is fixin’ to learn you some chemistry!

Twenty-four pairs of eyes are upon me.  These eyes, these critical eyes, belong to 12-year-olds.  Twelve-year-olds who expect this real-life scientist standing in front of them to teach them about ocean acidification (OA).  They’ve had no chemistry and I’ve never taught middle-schoolers.  Do they know about pH?  What makes an acid?  Calcium carbonate?  No?  I’ve got 50 minutes?  Deep-breath.  Okay.  Go!

Over two days last week I taught OA to 200 7th graders at the Rupert Nock Middle School in Newburyport, Massachusetts.  We tested household solutions (e.g., milk, lemon, spit) with pH strips.  We learned how added CO2 lowers pH.  We learned about chemistry through role-playing as elements and compounds.  We learned how the loneliness of H+ ions (lonely ions like to bond) make them highly reactive and how that loneliness can steal the bricks (carbonate) needed to build the shells of marine organisms (Thanks to science teacher John Reynolds for a wonderful Home Depot metaphor that I will blatantly steal).  We developed hypotheses about the consequences for marine life and conducted a multi-day experiment on the effects of an acid (dilute vinegar) on mass loss of bivalve shells.

 

While OA is not a current focus of the TIDE Project, it is a major concern for marine ecosystems.  Outreach is a supporting pillar of the TIDE Project’s scientific philosophy (as well as the larger group of Plum Island-LTER scientists) and one goal is to strengthen coastal education by working with young scientists and K-12 students.

My classroom demonstrations also emphasize the important presence the TIDE Project has in the communities local to the marshes we study.  The OA module germinated from a conversation I had when John Reynolds brought a dozen of his students to the marsh as part of his outdoor curriculum.

From middle-school students peering through refractometers while standing on the marsh to undergraduates publishing papers, the TIDE Project has engaged at over 1000 middle-school, high-school, undergraduate, and graduate students combined through its outreach activities.  Whether standing at a whiteboard or knee-deep in marsh mud, we hope to engage thousands more.

David Samuel Johnson is a principal investigator on the TIDE Project.  He is particularly fond of invertebrates.  All photos courtesy of Lisa Furlong.

 

Here a snail but not there a snail?

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Though unnoticed on my first visit to the Rowley marshes, I soon became well acquainted with Melampus bidentatus, or the coffee bean snail, during subsequent stem counting, transplant planting, and genetic sampling ventures. While working in close proximity with the coffee bean snails, I began to notice trends in their distribution across the high marsh. Coffee bean snails appear more abundant but smaller in Spartina patens dominated high marsh, less abundant but larger in short form S. alterniflora dominated high marsh, and conspicuously absent from the tall form S. alterniflora where the high marsh borders the creek bank. The question is: what factors are determining the distribution of coffee bean snails on the high marsh at Plum Island? I needed to know more about the snails.

Coffee beans snails are pulmonate (air-breathing) as adults but are tied to the sea by a planktonic larval stage. Snail spats settle into the high marsh at the size of 690 um and do not reach their adult size of ~12 mm until over a year of growth (Apley, 1970). Coffee bean snails feed mainly on decaying plant matter and algae (Graca et al., 2000). A number of marsh predators prey on coffee bean snails such as the ubiquitous mummichog, many different marsh birds (Hausman, 1932), and green crabs (David Johnson, pers. comm.).

Could predation be the key to snail distribution? A 1976 study by Vince et al. supports the predation hypothesis. This study shows that the high stem density of S. patens acts as a natural ‘fence,’ excluding predators from eating palatable snails. Thus, small snails, which make up the majority of the population, are confined to S. patens by predation pressure, while larger snails inhabit the low stem density, ‘un-fenced,’ S. alterniflora habitat because their size protects them from most predation. Vince et al. (1975) hypothesizes that larger snails are drawn into the higher risk habitat because the lower snail density in S. alterniflora may lead to greater resources per snail. This study may explain the difference in snail sizes and abundance I observed between S. Paten habitat and short form S. alterniflora habitat on the high marsh. But what about the complete absence of snails in the tall form S. alterniflora on the creek bank edges at the Rowley Marshes?

Dr. David Johnson (aka Mr. Marsh to the Marshview House faithful) posited an alternate hypothesis. He suggests that physiological limitations are the primary driver of coffee bean snail distributions. Because coffee bean snails are air breathing, they do not thrive in areas with a high frequency of tidal inundation. S. patens occurs at higher elevations on the marsh platform (wet only during spring tides). Conversely, the tall form S. alterniflora dominated habitats on creek bank edges are likely the lowest areas of the high marsh (wet at almost every high tide). Differences in the frequency of tidal inundation across habitats could influence the abundance of coffee bean snails on the high marsh. Just as too much water can drown snails at high tide, too much sunlight can cause desiccation at low tide. As a result, coffee bean snails avoid direct sunlight (Hausman, 1932). Larger snails may be more resistant to desiccation than their smaller counterparts. High marsh short form S. alterniflora seems to provide less percent cover than S. patens and this difference in shading could influence the abundance and size of coffee bean snails in these habitats.

I cannot test these competing snail hypotheses at the moment due to the frozen creeks and snowy peat of the winter marsh. Indeed the short days and cold weather has put an end to most marsh fieldwork and I have been effectively exiled to the lab until spring. For now, I am stuck with many questions, some guesses, and no answers. However, the New England winter gives me time to hone my knowledge and plan my approach so that when I get the chance, I can pursue informative questions in an efficient manner. In a way, by taking a step out of the marsh, I am gaining a better understanding what I want to do on the marsh and how I want to do it.

Forest Schenck is a Research Technician at Northeastern University Marine Science Center in Nahant, Mass.  He works with TIDE collaborators Drs. David Kimbro and Randall Hughes of Northeastern.

Rise of the Chog

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Talia Hughes holds a large mummichog
Talia Hughes holds a monster mummichog. Seriously, that’s a monster ‘chog.

We all know that fertilizer grows plants, but can it grow fish?  The answer turns out to be yes in salt marshes according to a new TIDE paper published in Marine Ecology Progress Series by Konner Lockfield and John Fleeger of Louisiana State University and Linda Deegan of the Marine Biological Laboratory.  After six years of nutrient enrichment at the landscape scale (350-500m of tidal creek length, a total area of 60,000 m2, the abundance and biomass of the dominant marsh fish, the mummichog Fundulus heteroclitus, increased by up to 60%.

How does fertilizer make fish?

“Of course fish don’t directly eat the fertilizer,” John said in an email.  “Fertilizer helps plants and algae grow and even improves the nutritional value of these primary producers.  In salt marshes, snails and a legion of small crustaceans (including grass shrimp, amphipods, isopods, and copepods) increase in abundance because their food supply is enhanced.  [Mummichogs] forage for these small invertebrates.  The increased amount and value of food below mummichogs on the trophic ladder leads to a “bottom-up” stimulation of mummichogs that was started by the addition of fertilizer.”

This paper is the first to experimentally demonstrate bottom-up control on the secondary production of salt-marsh fish.

It is the first study of it’s kind because fish are highly mobile and cover a lot of ground, er, water.  Mummichogs have a home range of 300-500 m, which is the length of tidal creek fertilized by the TIDE Project.

Because of the size of the experiment, the study required tremendous effort.  Konner, the lead author, coordinated a swarm (a dozen) of undergraduates, high school, graduate students, and post-docs to collect and tag 7828 mummichogs with coded-wire tags for this large-scale mark and recapture study.  Konner was understated when he said, “It was a lot of work.”

A surprising finding from the study is that in the fertilized creeks fish had more algae in their guts.  “Mummichogs are omnivores meaning they consume plant matter, algae, and animals,” John said.  Previous TIDE work has shown that can exert strong top-down control on algae in certain scenarios.

John asserts, however, “We aren’t sure why mummichogs eat more algae in fertilized creeks.  Animal prey is richer in protein than algae and should promote faster growth.  Theoretically then, mummichogs should prefer animal prey and should increase animal consumption when the food web is stimulated.”

Konner suggests another hypothesis, “One possibility is that they’re eating it incidentally as they consume more benthic prey.”  Konner agrees with John’s assessment that, “More research is needed to examine the behavioral and dietary preferences in mummichogs and the nutritional content of the various food sources when grown under fertilization.”

The fertilization conducted by the TIDE Project mimics run-off of nutrients (nitrogen and phosphorus) from agriculture and sewage sources.  The current study suggests positive effects of this run-off on fish production in the short-term.  We remain uncertain, however, about long-term effects, which may be detrimental.  For instance, we have found that chronic enrichment fragments the vegetated low marsh. Loss of this habitat may ultimately affect fish production in the long run.  We continue to study this question to understand the fate of our marshes in ever-changing conditions.

This work was funded by the National Science Foundation under Grant Nos. 0816963, 0923689 and 0423565.

Fundulus fun facts – the term ‘mummichog’ is an Indian term meaning ‘going in crowds’.  They are also called ‘killifish’ (as are a host of other minnows).  ‘Kill’ comes from the Dutch word for river or stream.  Thus, killifish are river/stream fish!

This publication is part of Konner Lockfield’s Master’s thesis from the TIDE Project.  He is currently employed the Audubon Aquarium of the Americas (lucky!) in New Orleans, Louisiana.

Dr. John Fleeger is emeritus at Louisiana State University and though he technically retired, he stays active as an adjunct professor at the University of Missouri at Kansas City where he teaches Ecosystem Science and Ecotoxicology and is able to spend more time with his grandkids.

Dr. Linda Deegan is a Senior Scientist at the Marine Biological Laboratory but decided that wasn’t enough work so she is currently on leave as a Program Director at the National Science Foundation in Washington, DC.

Lockfield, K., J.W. Fleeger, and L.A. Deegan. 2013. Mummichog Fundulus heteroclitus responses to long-term, whole-ecosystem nutrient enrichment. Marine Ecology Progress Series, 492:211-222.

David

The marsh: a living laboratory

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Gulp! Phragmites can swallow all.
Gulp! Phragmites can swallow all.  Mr. Reynolds and students.  All made it out alive.

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 maenasMore 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?

Dr. David Johnson, TIDE PI, showing students coffee bean snails. Note the notebooks and the genuine curiosity!
Dr. David Johnson, TIDE PI, showing coffee-bean snails. Note the notebooks and the genuine curiosity!  Photo credit:  John Reynolds

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

Pickleweed (or sea-pickle)

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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 a line of scarlet as the pickleweed has 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 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.

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 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

The cowlicks of the marsh

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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.

Though he retired half a decade ago, Professor Warren can't help giving impromptu lectures in the field.
Though he retired half a decade ago, Professor Warren can’t help giving impromptu lectures in the field.

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 cynosuroidesSpartina 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

 

1,103,003,440 Nitrate pellets later

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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 BehringerImage

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David dissecting mummichog stomachs
Nate sorting stomach content under the microscope.
Nate sorting stomach content under the microscope.
Erica and Hannah from Governor's Academy helping to measure, sort, and count the fish.
Erica and Hannah from Governor’s Academy helping to measure, sort, and count the fish.