Category Archives: In the Grass

Dr. Randall Hughes, among other things, studies biodiversity in salt marshes, and how it affects the habitat’s ability to cope with disturbances.  Does having a greater variety of plant species benefit a salt marsh?  Does having more genetic individuals of smooth cordgrass help when environmental or man made catastrophes strike?  Randall is looking at several factors, from the animals that eat the cordgrass (the foundation species of the marsh), to which combinations of plants work best together, or how seagrass wrack affects the health of a marsh.

Most of her study is centered on St. Joseph Bay, on Florida’s Gulf coast.  On this blog you will also see some of her side projects looking at black mangroves are starting to become more prevalent in Gulf salt marshes and why seagrass beds around the world are dying off.

Meet the animals of a coastal salt marsh.

The circle is complete.  Randall was once the middle school student being led into a marsh for the first time, she now leads middle school girls in.

WFSU SciGirls “In the Grass,” Talking Science

Episode 2: Talkin’ Science

In September we’ll tour our coastal ecosystems and learn why we love them.  These next couple of weeks, we’ll get a fresh set of eyes on Randall and David’s world of research and ecology as the WFSU/ Mag Lab SciGirls visit the FSU Coastal and Marine Lab.

Dr. Randall Hughes FSU Coastal & Marine Lab

Randall explains experiment to SciGirlsWhen you think of your summer vacations during middle school, what do you think of? The first thing that comes to my mind is HOT (it was south Georgia, after all), and the next thing is Duke. I realize that is somewhat sacrilegious for someone who went to UNC-Chapel Hill for undergrad (at least if you care anything about basketball). But I spent 4 summers as a student at the Duke University Talent Identification Program, better known as TIP, and my 3 weeks spent there each summer definitely stand out in my mind.

It sounds horrible to most people – 3 weeks during summer vacation spent taking an intensive course that would typically last a semester. Although we spent a lot of time in class and studying, in many ways it was like any other summer camp, with time spent goofing off with really interesting and fun classmates from all over the country. I even crossed paths with some of my fellow TIPsters in graduate school!

SciGirls trek into the marshSo what does this have to do with In the Grass, On the Reef? In many ways, nothing. But in some ways, everything. Because one of those summers I took Marine Biology at the Duke University Marine Lab in Beaufort, NC, and it was there that I fell in love with doing research on coastal systems (and did my first experiment on fiddler crabs!). Admittedly, it still took me a while to figure out how to turn that into a career, but I’m not sure that I would be where I am today were it not for 3 weeks during the summer before 8th grade.

Enter the SciGirls. For the last 4 summers, I’ve been thrilled to participate in the SciGirls summer camp run by WFSU and the National High Magnet Field Laboratory (aka, the Mag Lab), aimed at introducing middle and high school girls to careers in science. Although the SciGirls program is structured differently from the TIP program that I participated in, it provides me an opportunity to share my love of field research with some really amazing girls, and hopefully to plant the seed in their minds that they can turn their love of science into a career too.

This year, in addition to explaining my research to the SciGirls and getting their help collecting data, we talked about the importance of being able to communicate what you’re doing to others. It turns out that explaining research to non-scientists is not something that scientists are trained to do, and it doesn’t always come easy.  So we decided to start early with the SciGirls and see what happens!   As you can see from the video, they quickly grasped what they needed to do and were quite comfortable with the camera. There were some discrepancies among the observations, but hey, that’s why we take lots of data – you can’t always see the overall pattern when you’re only looking at a subset of the information!

The circle is complete. Randall was once the middle school student being led into a marsh for the first time, she is now the one leading middle school girls in. Might this fiddler crab have inspired someone into a career in research?

After a lunch break and a look at the results of our data collection, we headed to the field. This part of the day is always my favorite – watching the girls explore, answering their excited questions, helping them pick up their first fiddler crab, assuring them their shoes / clothes will come clean.  Even a short rainstorm didn’t dampen their enthusiasm. I would venture a guess that when these girls look back on their middle school summer vacation, their memories of SciGirls will be front and center.

For more on the SciGirls’ day at FSUCML, check out their blog.  And check back next week for video of their experiences in the grass (and mud)!

Music in the video by grapes.  In the Grass, On the Reef theme music by Lydell Rawls.

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

This attractive gastropod, seen int he video above, is a busycon snail wrapped around an atlantic moon snail that it just happens to be eating.  Nature videos have have a cast of human, animal, and plant characters.

Video: Where the Land Meets the Sea

Episode 1: Where the Land Meets the Sea

Rob Diaz de Villegas WFSU-TV

This time around, everything is both familiar yet new.

On the new tiles, spat are glued on with a mixture used to repair boat hulls.

I recently went to Saint Augustine to document the second version of Dr. David Kimbro and Dr. Randall Hughes’ tile experiment.  The basic concept is this: attach a certain amount of oyster spat (larval oysters- basically little blobs in the process of growing and building shells) to tiles, leave them on or by oyster reefs and see how they grow, or if they are eaten.  I’ll let Randall and David explain the intricacies of the experiment when we post those videos in January.  Or, you could watch our coverage of that first experiment, conducted in the fall of 2010.  Watching that video and then watching our new videos on the experiment, you’ll notice that both the approach to the experiment and to the video coverage have evolved.  After the Kimbro lab spent so many long days scrambling to collect spat, The 2010 experiment didn’t succeed like they’d hoped.  Likewise, our communication of their research, and the importance of the ecology of intertidal ecosystems, didn’t quite succeed like I had hoped.   I like watching the old videos; I just don’t think they did what we wanted them to.  But you learn, and hopefully, you improve.

This time around, I was struck by how orderly everything was at the Whitney Lab as the oyster crew prepared their tiles.  No more scrambling out at low tide to collect oysters; they had hired someone to breed spat from oysters spanning the Eastern seaboard.  The current tile design and construction had been tested, and would withstand the elements.  Randall and David had learned lessons, and were efficiently implementing their new plan.  But what had I learned?

This attractive gastropod, seen in the video above, is a busycon snail wrapped around an atlantic moon snail that it just happens to be eating. Nature videos have a cast of human, animal, and plant characters.

Early last year, WFSU had a moment equivalent to that of the Hug-Bro labs’ realization that the glue on their initial tiles couldn’t withstand the waves at their sites.  The National Science Foundation had rejected our grant application to fund this project.  After a few months of following their studies and a couple dozen videos, a panel of reviewers let us know everything they thought we did wrong.  That was fun.

When Randall, David, Kim Kelling-Engstrom (WFSU’s Educational Services Director) and I decided to reapply for the grant, we needed a new narrative for what it was that we wanted to communicate.  What was our story?  If you watch our old videos, we’re very narrowly focused on experiments and field work.  There’s a lack of perspective on the impact of the ecosystems on our area, a lack of local color from the excellent locations we visit, and I kind of feel like we could have better captured what a day on a salt marsh or oyster reef was like.  The new application reflected more of the world around the reefs and marshes, and the people who need them.  If you’ve watched the video above, you may have figured that this time, our application was successful.

The red snapper being held by Ike Thomas, owner of My Way Seafood, was caught in 150 feet of water. Before reaching market size, younger snapper are one of many fish species that forage on oyster reefs.

I’m finding the new videos are more fun to put together.  We’re exploring the area more, talking to more people, and it’s easier to spot the animals we care about and get footage of them.  And with funding we have some extra staff helping on the blog and on shoots (like new associate producer Rebecca Wilkerson).  The upcoming videos are like the new tiles sitting in their cages off of Saint Augustine oyster reefs: they are the product of some hard won knowledge.  That experiment ends soon and they’ll see if they get the data they needed to meet their larger goals.  We, on the other hand, are just getting started, and we hope that you’ll keep joining us as we explore that area where the land meets the sea.

Over the next couple of weeks, we see the WFSU SciGirls visit the FSU Coastal & Marine Lab to learn about what Randall does: in the marsh, at the lab, and in front of the camera.  It gets a little messy.  In September, we go in the field with Randall and David onto oyster reefs and into seagrass beds and salt marshes.

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

Music in the piece was by Kokenovem and airtone.

A long time in the making

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biodiversity 150

As I mentioned in my last update, we have been working to set up a new marsh experiment in St. Joe Bay. The goal of the experiment is to see whether the genetic diversity of marsh cordgrass (Spartina alterniflora) affects how quickly or abundantly the plants grow, or influences the number of fiddler crabs, grasshoppers, snails, and other critters (like Ibis??) that call the plants home. But what is genetic diversity, exactly, and why do we think it may be important?


A flock of Ibis resting among our experimental marsh plots.

Spartina is a clonal plant, which means that a single “individual” or clone made up of many stems can dominate a large area (low diversity), or there can be lots of different individuals mixed together (high diversity). In our surveys of marshes in the northern Gulf of Mexico, we find that there can be as few as 1 and as many as 10 clones in an area of marsh about the size of a hula-hoop. You may notice that our experimental plots are about that same size, though we used irrigation tubing rather than actual hula-hoops (not as fun, but more practical and less expensive!). We’re testing whether the differences in genetic diversity (1 vs. 10 clones) that we see in natural marshes has any influence on the marsh community.

A single experimental plot of Spartina that is 1m in diameter.

But why genetic diversity? We know from experiments by other researchers that Spartina clones grown individually differ in height, how many stems they have, and other characteristics. These same plant traits affect the critters that live in and among the plants – for example, periwinkle snails preferentially climb on the tallest plants. Because different animals may be looking for different plant traits, then having greater diversity (genetic and trait) may lead to a greater number of animal species that live in that patch of marsh. Or, a single clone may be the “best”, leading to higher numbers of animals in lower diversity areas.


A view of the existing marsh behind our experiment.

As my title alludes, this experiment has taken a long time to come to fruition, in large part because it’s impossible to look at any 2 stems in a marsh and know for certain whether they’re the same individual or not. Unlike some clonal plants such as strawberries, where there are multiple berries connected by a single above-ground “runner”, Spartina has runners (aka, rhizomes) that connect stems of the same genetic individual under the ground, making it difficult to tell which stems are connected to which. We have 2 ways to get around this problem: (1) we use small snippets of DNA (analyzed in the lab) to tell clones apart, and (2) we start with single stems that we know are different clones and then grow them separately in the greenhouse until we have lots of stems of each different clone. It’s this latter part that has delayed this experiment – it has taken much tender loving care from Robyn over the last 2 years to get our Spartina clones to grow in the greenhouse to the point that we have enough of each clone (36 small flowerpots of each, to be exact) to plant in our experiment.


Emily and Robyn work to remove existing rhizome material from around the plot edges.

But plant we finally did! With lots of help from members of the Hughes and Kimbro labs, we got all the sand in the experimental plots sieved (to remove any existing root material) and all the plants in the ground the Thursday and Friday before Thanksgiving.


Team Hug-bro (Hughes and Kimbro) helping sieve sand!



Meagan and Randall get the easy job - planting the plants.

Now we get to wait and see (and take data) whether Spartina genetic diversity matters for the marsh plant or animal community. There won’t be any quick answers – the experiment will run for at least 2 years – but we’ll be sure to keep you up-to-date!

Randall’s research is funded by the National Science Foundation.

Tricks or Treats? And more on the effects of predators in marshes.

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip_ predators_NCE 150Unlike most of the experiments that I’ve conducted up to this point in my career, the oyster experiment from this past summer does not contain a lot of data that can be analyzed quickly.

For example, predator effects on the survivorship of oysters can be quickly determined by simply counting the number of living as well as dead oysters and then by analyzing how survivorship changes across our 3 experimental treatments (i.e., cages with oysters only; cages with mudcrabs and oysters; cages with predators, mudcrabs, and oysters).  But this simple type of data tells us an incomplete story, because we are also interested in whether predators affected oyster filtration behavior and whether these behavioral effects led to differences in oyster traits (e.g., muscle mass) and ultimately the oyster’s influence on sediment characteristics.  If you recall, oyster filter-feeding and waste excretion can sometimes create sediment conditions that promote the removal of excess nitrogen from the system (i.e., denitrification)


As we are currently learning, getting the latter type of data after the experiment involves multiple time-consuming and tedious steps such as measuring the length and weight of each oyster, shucking it, scooping out and weighing the muscle tissue, drying the muscle tissue for 48 hours, and re-weighing the muscle tissue (read more about this process here).

After repeating all of these steps for nearly 4,000 individual oysters, we can subtract the wet and dry tissue masses to assess whether oysters were generally:

(a) all shell…“Yikes! Lot’s of predators around so I’ll devote all of my energy into thickening my shell”

(b) all meat…“Smells relaxing here, so why bother thickening my shell”

(c) or a mix of the two.

For the next two months, I will resemble a kid with a full Halloween bag of candy who cannot wait to look inside his bag to see whether it’s full of tricks (nonsensical data) or some tasty treats (nice clean and interesting data patterns)!  I’ll happily share the answer with you as soon as we get all the data in order.

Because of this delay, let’s explore some new research of mine that examined how predators affect prey traits in local marshes and why it matters.


There are two main ingredients to this story:

(a) tides (high versus low) dictate how often and how long predators like blue crabs visit marshes to feast on tasty prey.

(b) prey are not hapless victims; like you and me, they will avoid risky situations.

attach.msc1In Spartina alterniflora systems, periwinkle snails (prey) munch on dead plant material (detritus) lying on the ground or fungus growing on the Spartina leaves that hover over the ground.  Actually, according to Dr. B. Silliman at the University of Florida, these snails farm fungus by slicing open the Spartina leaves, which are then colonized by a fungal infection.  If snails fungal farm too much, then the plant will eventually become stressed and die.

So, I wondered if the fear of predators might control the intensity of this fungal farming and plant damage.

For instance, when the tide floods the marsh, snails race (pretty darn fast for a snail!) up plants to avoid the influx of hungry predators such as the blue crab.

After thinking about this image for a while, I wondered whether water full of predator cues might enhance fungal farming by causing the snail to remain away from the risky ground even during low tide.  Eventually, the snail would get hungry and need to eat, right?  Hence, my hypothesis about enhanced fungal farming due to predator cues.   I also wondered how much of this dynamic might depend on the schedule of the tide.

Before delving into how I answered these questions, you are probably wondering whether this nuance really matters in such a complicated world.  Fair enough, and so did I.

Addressing this doubt, I looked all around our coastline for any confirmatory signs and found that Spartina was less productive and had a lot more snail-farming scars along shorelines subjected to a diurnal tidal schedule (12 hours flood and 12 hours ebb each day) when compared to shorelines subjected to a mixed semidiurnal schedule (2 low tides interspersed among 2 high tides that are each 6 hours).  Even cooler, this pattern occurred despite there being equal numbers of snails and predators along both shorelines; obviously density or consumption effects are not driving this pattern.


Ok, with this observation, I felt more confident in carrying out a pretty crazy laboratory experiment to see if my hypothesis might provide an explanation.


Enter Bobby Henderson.  This skilled wizard constructed a system that allowed me to manipulate tides within tanks and therefore mimic natural marsh systems; well, at least more so than does a system of buckets that ignore the tides.


Within each row of tide (blue or red), I randomly assigned each tank a particular predator treatment.  These treatments allowed me to dictate not only whether predators were present but whether they could consume & frighten snails versus just frightening them:

-Spartina only

-Spartina and snails

-Spartina, snails, and crown conch (predator)

-Spartina, snails, blue crab (predator)

-Spartina, snails, crown conch and blue crab (multiple predators)

-Spartina, snails, cue of crown conch (non-lethal predator)

-Spartina, snails, cue of blue crab (non-lethal predator)

-Spartina, snails, cues of crown conch and blue crab (non-lethal multiple predators)

attach.msc6After a few weeks, I found out the following:

(1) Predators caused snails to ascend Spartina regardless of tide and predator identity.  In other words, any predator cue and tide did the job in terms of scaring the dickens out of snails.

(2) Regardless of tide, blue crabs ate a lot more snails than did the slow moving crown conch and together they ate even more.  This ain’t rocket science!

(3) In this refuge from the predators, snails in the diurnal tide wacked away at the marsh while snails in the mixed tide had no effect on the marsh.


Whoa…the tidal schedule totally dictated whether predator cues indirectly benefitted or harmed Spartina through their direct effects on snail predator-avoidance and farming behavior.  And, this matches the observations in nature… pretty cool story about how the same assemblage of predator and prey can dance to a different tune when put in a slightly different environment.  This study will soon be published in the journal Ecology.  But until its publication, you can check out a more formal summary of this study here.

If this sort of thing happens just along a relatively small portion of our coastline, I can’t wait to see what comes of our data from the oyster experiment, which was conducted over 1,000 km.

Till next time,


David’s research is funded by the National Science Foundation.

The making of an experiment

Dr. Randall Hughes FSU Coastal & Marine Lab

“Wow, quite the set-up! I am jealous of that space!

“…As a side question, how did you pump the cue water to all your tubs, a peristaltic pump? Was it just gravity? Seems like quite the complicated set-up.”

Excerpts from a comment on Randall’s September 28th post, Scared Hungry.  Read the whole comment here.

IGOR chip- employment 150This recent comment by John Carroll made me realize that there are a lot of unsung heroes at the lab that don’t typically get credit for the essential work that they do to facilitate our research. So here is a ‘behind-the-scenes’ look at setting up an experiment:

1. The idea. This is the main part that I can take credit for, though even then an idea usually stems not simply from my brain, but from a paper I’ve read, a conversation with a colleague or student, or an observation in the field.

2. The infrastructure. Each experiment has its own specifics, but in my research there are generally 3 main requirements:


The "small" deck, used by David and me for mesocosm experiments with snails, crabs, plants, oysters - you name it!

a. Space. FSUCML has numerous tanks and related facilities for use in research (Visit the Lab site here.). Of course, I often have specific needs or desires, and thus my first step is usually to speak to Mary Balthrop, our Associate Director, and then to Dennis Tinsley, our Facilities Manager. Both Mary and Dennis show a great deal of good humor in receiving my seemingly hair-brained requests (e.g., a deck that can hold 16 plastic kiddie pools full of sand and water!), and they work with me to find (or devise) a suitable space to get the job done. Our incredible carpenter, Dan Overlin, then has the task of modifying or creating that space.


The newer "large" deck, obscuring the view of the small deck closer to the water's edge


Another view of the small deck, with the large seawater tanks in the background. (Photo credit: Nancy Smith)

b. Seawater. Since we work with marine critters, access to seawater is critical. FSUCML pumps seawater from the bay in front of the lab into large holding tanks that feed the entire facility.

Mark Daniels and Bobby Henderson then create the plumbing system that gets that water where it needs to go. They know everything there is to know about PVC pipes, water filters, pumps – you name it! As I mentioned in my response to John, it was Bobby who came up with the incredible pump apparatus (and several subsequent revisions) that has enabled us to conduct several experiments examining the effects of predator cues on prey behavior.


Robyn and Emily working to set up a recent experiment on the large deck. Although the plants love all the light, we decided to erect a tent as a refuge from the sun/heat.

c. Light. When working with plants, light is key. I’m fortunate to have access to a greenhouse, as well as abundant outdoor space at the lab to set up experiments. Or perhaps I should say once-abundant outdoor space, since David and my decks now cover a good chunk of it! Dennis is a pro at thinking of suitable and available spaces to squeeze in a few tanks.

Robyn and Emily releasing grasshoppers into one of our cages. (Photo credit: Nancy Smith)

3. The supplies. Once the infrastructure is in place, it’s time to buy the supplies needed to make each experimental unit. The job then falls to Kathy Houck and Maranda Marxsen to explain to the accountants at FSU why I purchased several large bolts of tulle fabric (grasshopper cages), or 24 pair of knee-high panty hose (they make great filters when filled with gravel), or lots and lots of nail polish (for marking snails). For field experiments, Sharon Thoman is helpful in arranging vehicles and boat reservations, sometimes at the very last minute!


Robyn and Liz cheerfully using nail polish to mark snails



A thundercloud looms in the distance. Once this summer we were stranded in a storm and Dan came to retrieve us.

4. Set-up. Once things start to come together, there are inevitable surprises the crop up. In our recent predator-prey experiments, we had issues with flow from the pump being greater than that from the regular seawater lines, which required some brain-storming from Bobby, David, Kelly, Meagan, and myself. Or, a plumbing line will clog, and I’ll run to find Mark.  Or, we’ll get stranded in a thunderstorm while collecting mud crabs and Dan will come pick us up.   At least we often provide fodder for funny stories!

5. The experiment. And at last, the actual experiment can begin. When I come up with particularly high-maintenance experiments, it’s useful to utilize the lab dorms for the night. Linda Messer is always understanding of last minute housing requests and changes, making sure the lights (and, more importantly, the A/C) are on! Sometimes, the experiment itself is much shorter than the time required to set it up – duration never seems to equate with complexity. But one of the benefits of consulting with the staff is to ensure that the same space can be used for multiple purposes. And the second experiment is always easier to set up than the first!

Randall and David’s research is funded by the National Science Foundation.


We finished the first pass of sample processing for site one. Now, we are waiting for the evening tide to drop so that we can begin breaking down our second site.

Crew is a little grumpy because I keep getting us to the sites too early!


Are two friends better than one?

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biodiversity 150

Sand fiddler crab.

This summer we’ve been conducting an experiment on our new deck to look at the effects of fiddler crabs and ribbed mussels on Spartina alterniflora (smooth cordgrass).

Past studies by Dr. Mark Bertness have shown that crabs and mussels by themselves can have positive effects on plant growth – most likely because crabs can reduce the stress of low oxygen in the sediments by building their burrows, and mussels can add nutrients to the sediments.

Fig. 3 from Bertness 1984, Ecology 65: 1794-1807

Figure 3 from Mark Bertness's 1984 Ecology study illustrating the positive effects of mussel presence (white bars) on Spartina

Table 3 from Bertness 1985, Ecology 66: 1042-1055

Table 3 from Mark Bertness's 1985 Ecology study. Fiddler removal has a negative effect on Spartina in the marsh flat, but not the marsh edge.

Although both fiddlers and mussels occur together in the field, no studies have looked at how the combination affects the plants. Are the positive effects of each species by itself doubled? Or are they redundant with each other? Do crabs somehow reduce the positive effect of mussels, or vice-versa? How many crabs or mussels do you need to get a positive effect on Spartina? These are some of the questions that we hope to answer with our experiment.


Our new deck at FSUCML.

But first, we had to get everything set up. There were several long and hot days of shoveling sand into our “mesocosms” (10 gallon buckets) – many thanks to Robyn, Chris, Althea, and all the others who took care of that task! Then there was another day spent transplanting the Spartina.


Chris, Randall, and Robyn work to transplant Spartina from the greenhouse to the mesocosms.

Finally, it was time to add the fiddlers and mussels, and everything began!


Mussels nestled among the Spartina stems in one of our experimental mesocosms

Althea and Chris have been leading the charge on this experiment, and they’ve spent a lot of time getting to know (and identify) the fiddler crabs. All in all, a pretty fun study organism!


Althea working to identify fiddler crab species.

We’ll continue the experiment another month and then measure the height and density of the plants in each treatment to see if there are any differences. Once this experiment is complete, we’ll set up a separate one asking somewhat of the converse question – are two enemies (periwinkle snails and grasshoppers) worse than one? We’ll keep you posted.

Randall’s research is funded by the National Science Foundation.
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