Tag Archives: periwinkle snails

The “In the Grass” Top 10 of 2010

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biodiversity 150IGOR chip- employment 150 In keeping with all of the other end-of-year top 10 lists, I’ll wrap up 2010 with my own observations and highlights from In the Grass

10. No tarballs – yet??
The over-riding event of the 2010 research season was undoubtedly the Deepwater Horizon oil spill. (In fact, that was the impetus for the start of this blog!) Early in the summer, I thought our marsh field sites in St. Joseph Bay were doomed to be covered in oil. I am very relieved to say that is not the case – there are no visible signs of oil at our sites. It’s too soon to say we’re in the clear, because there is still a lot of oil that is unaccounted for, and there could certainly be “invisible” traces only detectable by laboratory analyses. However, we’re in much better shape than I would have predicted back when this all began, and that’s as good a way as any to start a new year!


Members of Team Hughes surveying the marsh.

9. It takes a lot of people to conduct scientific research.
I had a lot of help over the course of the last year – Team Hughes consisted of (in no particular order) Robyn Zerebecki, Ryan Corley, Emily Field, Althea Moore, Liz Hibner, Kristin Berger, Michele Sosa, Prathyusha Pamidi, and AJ Gelin, and we often enlisted members of Team Kimbro as well.

But even that list does not really represent all of the many people who help to get the work done. There are friends and family (thanks, Mom!) that get roped into helping when no one else is available. In addition, there’s an entire staff here at the FSU Coastal and Marine Lab who see to it that we have all the necessary paperwork complete, decks and tables for our experiments at the lab, seawater flowing to our tanks, irrigation systems in the greenhouse, boats and vehicles to get to our sites, and any number of other odd requests that we come up with. They don’t get nearly enough recognition for the critical role that they play!

8. It’s not as scary as I thought to have a camera documenting my every move in the field.
Field work is neither glamorous nor graceful, so I was a bit worried when we started this blog about having goof-ups documented on video. Thanks to the great work of Rob and his team, it’s actually been quite fun!  I hardly even notice their presence when we’re in the field, and I love having so many good photos of critters and field sites, since I’m notoriously bad about taking pictures.  Most importantly from my perspective, Rob has a great eye for what is important to include (the science, and the people and process behind the science) and what is not (my team and me clumsily getting out of our kayaks, which never fails to look silly!).

Lightning Whelk

Lightning whelks grace many of the habitats studied by Randall and David.

7. Marine plants and invertebrates are really cool.
Ok, this observation has nothing in particular to do with 2010, but I have to put in a plug for the amazing critters that don’t immediately come to mind when you think of charismatic marine animals. I’m talking snails, crown conchs, fiddler crabs, sea hares – all the little guys – and the habitats they live in – salt marshes, seagrass beds, and oyster reefs. Even nondescript sand bars are amazing. I was out last week with Cristina, a visiting researcher in David’s lab, on a sand bar near FSUCML. We found all sorts of large predatory snails (horse conchs, tulip snails, lightning whelks) as well as tons of sand dollars, clams, and worms. Just walking around, looking at, and counting these critters made for one of my most fun field excursions in recent memory. (It didn’t hurt that it wasn’t freezing cold.)

Learn more about the predatory snails Randall saw at Baymouth Bar.


Black mangrove (Avicennia) growing in St. Joe Bay

6. Sometimes things are hiding in plain sight.
When Dr. Ed Proffitt visited in the fall, I told him that I thought I may be able to find a spot in St. Joe Bay with 1 or 2 black mangroves for us to look at. Turns out, it’s harder to find a spot that does NOT have 1 or 2 black mangroves! I’m really interested to follow their abundance over the next few years to learn more about their response to climate change and their potential impacts on salt marsh systems in this region.

Read about Randall’s collaboration with Ed.

5. Going out on the reef is pretty fun, too.
Though I spend most of my time in the salt marsh, it was fun to return to oyster reefs this fall to collaborate with David, his team, and our more distant collaborators. A lot of the more mobile animal species in the marsh are also found on the reef (crown conchs, blue crabs), which is a reminder that we shouldn’t treat these different habitats in isolation of one another.

Randall writes about her return to the reef.

More snails climbing on cordgrass reproductive stems

Snails climbing on cordgrass reproductive stems in the field.

4. Snails are more complicated than you think.
It seems pretty straightforward – periwinkle snails climb on cordgrass to escape their predators and consume dead leaves / stems. Except that sometimes they prefer to climb on plants that they apparently don’t eat. And sometimes they create razor-like cuts in live cordgrass and graze the fungus that colonizes the resulting scar. And sometimes they climb up the plant but don’t eat anything, waiting instead until the water retreats and they can return to the sediment surface to consume plant litter…

On a related note, for Christmas my parents gave me the wonderful book The Sound of a Wild Snail Eating. The author, Elisabeth Tova Bailey, provides a compelling account of the delightfulness and intrigue of snails.

grasshopper grazing 3

Grasshopper grazing damage on a cordgrass stem

3. Grasshoppers eat a lot.

Snails are really abundant in the marsh, and because they don’t move very quickly, it’s impossible not to notice them and wonder about their effects. However, there’s a whole suite of bugs that don’t stay put long enough to be counted as easily (unless of course you suck them into a bug vacuum or catch them in a sweep net), grasshoppers being key among them. Our tank experiments show that the grasshoppers can consume lots of living plant material in a short period of time, serving as a useful reminder that I should wonder about the things I don’t see as much as those I do see.

Who can eat more- Grasshoppers or snails?

2. It’s fun to do science with friends.
A recent study indicated that scientific collaborations have a greater impact if the researchers work in close physical proximity to one another. I don’t doubt the results – who doesn’t find it easier to reach a consensus in person than over a Skype conference call? However, I’m happy to be working with David, Jon, Jeb, and Mike “on the reef” despite the geographic distance. Not only are they the right people in terms of research expertise, but our shared history makes it easier to communicate (including to give each other a hard time!).


Rainbow over St. Joe Bay on Christmas Day 2010 (photo credit: L. Hughes)

1. Did I mention that my research sites are not covered in oil?  Hooray!

Best wishes in 2011!

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

Cold and Wet: Field Research in the Winter

Waves on Cape San Blas rocks

Rob Diaz de Villegas WFSU-TV

IGOR chip- employment 150I was driving to Stump Hole with my production assistant Kevin when we saw these waves crashing on the rocks on the beach side of Cape San Blas.  Like any good production people, we knew the only thing to do was to climb the rocks and get footage and stills of the scene.  The same wind pushing the waves at us rocked us a little bit as we balanced- only slightly precariously- on the big stones.  It was a little after 8:30 AM and we had some time to kill before Randall and her team showed up.  And then we would kayak into the bay just across the street.

In early December I made my first winter forays into coastal environments.  Randall has already written about the seasonal shift from Summer to Autumn, where the flora and fauna are reproducing and animals are abundant in the marshes.  Winter is an entirely different beast, as I would see when we got to their sites.  But first, we actually had to get to these sites.


After everyone was there, we kayaked east from Stump Hole with a stiff north wind pushing us on our left.  Rowing to the left was like rowing into a wall, and there were a couple of marshes in our way where we had to get out and lug the kayaks to the other side.  Saltwater splashed into my eyes and onto my glasses.  I kept my squinty eyes forward and we got to a site that for the purposes of this study is known as Island 4.

The research crew went about their normal survey work, with Randall taking a quadrat to several specific spots within the marsh to see how much grass and other species were within its PVC boundary, how tall the grass is and how many Spartina shoots were dead.  Using markers and a GPS, they’ll have data from these precise spots over a span of three years.  Emily and Hanna vacuumed bugs out of the grass and surveyed seagrass wrack.  They will, as always, search for patterns over time, and I suspect the data collected in the winter months will quantify some of what we saw with our own eyes.

Sea Urchin shell washed up on marsh

While we didn't see the usual critters swimming and crawling about, some cool stuff washed in from the bay, such as sponges, lightning whelk egg casings, and this sea urchin shell.

Last time I was at this site, some male blue crabs were fighting over a female.  They were so engrossed that I was able to get fairly close without their bolting away.  All manner of predatory snails oozed about, little fish darted in and out of the sparse shoots at the periphery, and a ray laid low in an adjacent seagrass bed.  Today it looked like they had all packed up and left for the season.  And, when it came time to go our next site, so had the water in the bay.

A combination of the tide and the strong wind left the south side of the bay somewhat empty.  Taking a few steps with our kayaks in hand, we decided instead to leave them at the island while we walked our gear over to a mainland marsh known as Wrack 5.


This was another site where I had always seen an abundance of fauna. Hundreds, sometimes thousands of fiddler crabs would scurry away from me into the grass in this one corner of the marsh.  As Randall explained to me, the fiddlers bury themselves in the winter.  Blue crabs swim into the deeper part of the bay, to the north.  Randall didn’t know exactly what happened to the crown conchs, though when digging cordgrass up for an experiment she had come upon a buried conch.  And with their predators all gone, the marsh periwinkles had descended to the bottom of the spartina plants.

Lightning Whelk shellOne thing I did see a lot of were lightning whelk shells.  I picked them up and looked inside, wondering, are they more cold tolerant than the other species?  They’re not.  But their shells were pretty.

The following Monday I went to Alligator Harbor with Tanya and Hanna, and it was a lot of the same.  We dragged our kayaks from the ramp to the first site and walked between the islands to the second and third sites.  It was a much muckier walk than in St. Joe Bay (the oysters like it mucky), and I was breaking in a new pair of crappy old sneakers to be my oyster reef shoes.  This is how they fared:


Now that I’ve muddied my hands pulling my shoe out, where’s all that water?

Have any of you trekked out into the cold coastal waters this season? Share your stories!

Just one more thing…

Dr. Randall Hughes FSU Coastal & Marine Lab
Setting up a tank experiment

Emily and Robyn setting up yet another tank experiment that I've dreamed up. (Thanks to Nancy Smith for the pic!)

IGOR chip- biodiversity 150Because of the big focus on oysters over the last month, it may seem as if we haven’t been doing anything “In the grass”. We’ve been busy, though, trying to squeeze in a few additional surveys and experiments in November before it gets cold enough that the animals stop eating (or eating very much, I should say) and the plants stop growing. For a while there, I was coming up with so many end of season ideas that I’m pretty sure my crew hated to see me coming!  We just did finish up before the winter weather arrived (early) in December. (More on what it’s like working in this cold weather in future posts.)

We actually missed the opportunity to do one of our planned studies involving grasshoppers – there was a cold snap two nights before we went in the field to get the hoppers, and they were nowhere to be found.   Those data will have to wait until next spring when the grasshoppers turn up again!

We’ve had better luck with two other projects –

1. Do snails prefer to climb on cordgrass reproductive stems?

More snails climbing on cordgrass reproductive stems

Snails climbing on cordgrass reproductive stems in the field.

Spartina reproductive shoot

A tasty snack for a periwinkle snail?

I’ve mentioned before on the blog that we noticed lots of snails climbing on cordgrass reproductive stems this fall. In collaboration with David and his team, we visited marsh sites along the Panhandle to see if our observations would be supported with rigorously collected data. So far, so good!


The trusty tank set-up at FSUCML.

We also started a series of experiments in our trusty tanks at the FSU marine lab to tease apart why snails may have this preference: Do the snails simply like that the reproductive stems are taller than regular stems? Or do the reproductive stems “taste” better because of greater nutrient content? Does it matter if predators are present or not? The preliminary results suggest that they like the reproductive stems, regardless of whether they are taller or not. In January, we’ll head into the lab to do the tests for nutrient content that should help us to tease apart why that may be.

2. Does needlerush provide a better predation refuge than cordgrass?

A patch of needlerush surrounded by cordgrass

Needlerush (center patch) is typically much taller than cordgrass (surrounding area) in St. Joe Bay

Last fall I did a tank experiment to look at whether snails prefer to climb on another marsh plant species, needlerush (Juncus roemerianus), and whether this preference increased snail survival when predators were around. The results were interesting, but as usual, the first round of the experiment created additional questions that required more work. In November we started a similar experiment, again in the tanks at the marine lab, looking at snail climbing behavior on needlerush and cordgrass in the presence and absence of the snail’s nemesis, the blue crab.

Needlerush is naturally taller than cordgrass, so to test if this difference in height can explain snail behavior, we “experimentally manipulated” (in other words, used scissors to cut the needlerush down to a shorter height) needlerush height: some tanks have naturally tall needlerush, some have needlerush that is on average the same height as the cordgrass, and some have needlerush that is shorter than the cordgrass. Add a blue crab to half of the tanks, and voilà, the experiment is underway!

blue crabIt’s a bit ironic that each of the experiments we recently finished converged on a similar idea – snails appear to prefer to climb on taller plants. Considering that the taller the plant, the farther they can climb away from predators in the water, it makes sense. The true question is to figure out whether and why it matters that the snails do this. If they climb on reproductive stems, are fewer cordgrass seeds produced? What will that mean for next year’s crop of cordgrass? Also, if snails spend a lot of time hanging out on needlerush to avoid predators, does that mean they don’t eat as much cordgrass? Knowing things as seemingly arcane as which plant a snail prefers to climb on can help us predict and manage the overall abundance and productivity of cordgrass, and the salt marsh in general. And of course, the field work and experiments are fun! Especially when you get to wrestle with blue crabs…

Here are some photos of periwinkle snails in Randall’s latest tank experiments:

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

Day 5: October Oyster Push- A Change of Plans

Rob Diaz de Villegas WFSU-TV

Tuesday, October 26- Tile Team heads to Jacksonville


The whirring sound, the smell of calcium carbonate dust, the warmth of his face behind the mask and goggles- this is the stuff of David Kimbro's dreams.

IGOR chip- biogeographic 150The WFSU crew stayed the night in St. Augustine to accompany both the Net/ Fish and Tile teams when they headed out at sunrise.  After breakfast, I went out to the lab space (we’re all staying at a research facility very near the reefs they study), and David Kimbro was there, before the sun had made its way out, separating shards of shell with spat on them.  He’d missed all of the field work here up to that point so that this experiment could work.  Until this afternoon, it was all I had seen him do here.  If he was able to focus in on this one aspect of this large an undertaking, it is because Hanna and Tanya have been able to operate independently and pick up the slack.  By the time he actually made it into the field, David followed Tanya’s lead.

Also working hard on this trip are my poor sneakers.  I have an old pair that I designated for my work on this project, shoes I knew I would never wear for anything else.  The reefs in Cedar Key and St. Augustine have torn them up.  I keep stepping in soft mud that hides oysters, or stray clumps cloaked by muddy water.  It might be time to invest in boots.


There's nothing like the smell of dead fish in the morning.

7:30 AM- Hanna, Tanya, and Cristina went out to retrieve the catch from the gill nets, take sediment samples, retrieve the data loggers, and take some fish stomachs (how else would you know what the predators were eating?).  They also replaced the spat sticks, which were still only attracting barnacles.  Tanya noticed, however, that spat would settle on the rebar below the stick.

A couple of Environmental Scientists from the St. Johns River Water Management System agency kayaked up at some point to watch the proceedings.  They are working with David’s lab to determine why these once commercially viable reefs were overrun and depleted by crown conchs.  The problem seems to be very localized, occurring between Ponce Inlet in New Smyrna Beach and Matanzas Inlet.  David is hoping for more “spinoff projects” like this one, in which he and his lab can use applied science to help specific reef systems.

And while we’re on the topic of predatory snails, Here’s that pic of the Atlantic Oyster Drill:


Crown conch, tulip snails, and oyster drills heavily populate these Marineland, FL reefs.

2:30 PM- Hanna and Cristina headed to Jacksonville to begin removing clumps of reef with Jacksonville spat on them. But first they were to inspect the house they were renting to see if there was a suitable area to make their Jacksonville spat tiles. That process involves keeping oysters in large tubs of water, prying shells off of the clump, and using a dremel to make the pieces somewhat uniform in size. If I was renting someone a house, I wouldn’t want them doing that in my bathroom. Hanna determined that the house did not have a workable area, causing a shift in their plans. Hanna and Cristina now had to bring the reef segments back to St. Augustine to process. Instead of deploying nets in Jacksonville Wednesday morning, they’ll have to do this in the afternoon after processing the spat all day. And instead of finishing with Jacksonville on Thursday morning, they’ll be there all day (causing David to make his three hour drive home at night).

5:00 PM- David and Tanya retrieve the small fish traps.  A couple of the fish they catch are pretty colorful, I suspect they’re something that once lived in a saltwater aquarium.  They also deployed the tiles into which so much effort had been expended.  It’s a major part of this study, and David is happy to get started on it just five months after that first day in Alligator Harbor.  And it’s still early enough in this three year study that they can tweak the experiment and try it again next year (experiments of this nature don’t always work the first time).

After all the work was done, Tanya made a tasty four-bean vegetarian chili, and everyone enjoyed a relaxed dinner before convening again at 7:30 AM to process more spat.


David finally makes it out into the field.

Tide Times and height (ft.) for Saint Augustine, October 26, 2010
Low- 8:oo AM (0.3)
High- 2:17 PM (5.2)
Low- 8:41 PM (0.7)
Tide Times and height (ft.) for Jacksonville, October 25, 2010
High- 5:56 PM (0.5)
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The search for patterns

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biodiversity 150The end of summer is a good time to pause and think about any general patterns that emerge from observations over the course of the last year(s). Sometimes it is easy to get swept up in the minutiae of individual projects and forget about the big picture. Of course, these patterns aren’t definitive (i.e., don’t quote me on this!), but they can be useful to think about, particularly when considering future avenues of research.


Marsh island in St. Joe Bay viewed from the waterand marshes on the edge of the mainland.

So what sort of patterns can I describe to you after two summers in the marshes of St. Joe Bay? One that doesn’t take a PhD to recognize is that there are two distinct types of marshes that we sample: marsh islands and marshes on the edge of the mainland.

But aside from the obvious fact that one is an island and the other is not, there are some additional interesting differences:

1. The slope of marsh islands is typically greater than mainland marshes, so that you move quickly from plants that can tolerate frequent flooding (cordgrass) to plants that are more “terrestrial” (pickleweed, saltwort, etc.). On islands this transition can occur within a few steps of the water’s edge, whereas mainland marshes typically have a large area (I like to think of it as a football field) dominated by cordgrass.


Elevation on islands changes rapidly compared to the mainland. Even slight differences in height can influence plant communities.


Sampling a mainland marsh in St. Joe Bay.

2. Marsh islands tend to have fewer periwinkle snails than mainland sites, although they are certainly present.


Abundant snails in a mainland marsh.

My guess is that the snail predators (blue crabs, crown conchs) that lurk just at the water’s edge have greater access to snails on the islands at high tide, because they can move in from all sides of the island. In contrast, the predators near mainland sites have only one point of entry into the marsh.

blue crab

Blue crab lurking in the seagrass at the edge of the marsh during low tide.


Crown conch foraging for snails in a lab experiment.

3. Perhaps not surprisingly given that they are surrounded by water, the marsh islands typically have fewer grasshoppers jumping around. We’ve also had far fewer snake encounters on islands, which I consider a good thing. Probably because land-based predators such as snakes, raccoons, etc., are less frequent on islands, we also observe greater numbers of nesting birds on the islands than at mainland sites.

4. One clear difference that I can’t explain but hope to examine in the future is that cordgrass plants collected from the islands (which can only be done with a special permit from the Department of Environmental Protection) survive better in our greenhouse at the lab than those from mainlands. It may simply be the growing conditions, or island plants may be hardier overall. Stay tuned.

As we continue to process, enter, and analyze data, there should be additional trends emerging. And we’ll likely find out that some of the patterns we think we see don’t hold up to the test of actual data. And so goes the process of science!

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

Dr. Randall Hughes FSU Coastal & Marine Lab

Marsh periwinkles climbing on a cordgrass reproductive stem

A cordgrass reproductive stem stands above the surrounding plants.

IGOR chip- biodiversity 150 One doesn’t need to look at a calendar to realize that fall is upon us – recent cool mornings are a welcome sign. The marsh is also showing signs of change, with cordgrass flowering shoots springing up everywhere.

These stems are quite noticeable – they are taller than non-reproductive plants, and they have a “feathery” appearance due to the reproductive structures at the tops of the stems.

As I’ve mentioned before, cordgrass is one of those plants (like strawberries) that can spread by underground rhizomes, putting up new stems along the way. Alternatively, it can reproduce the “traditional” way, with reproductive stems that broadcast and receive pollen via the wind, ultimately producing seeds that fall to the sediment, get buried, and then germinate to produce new seedlings. Though conventional wisdom is that most new cordgrass stems are produced vegetatively by spreading rhizomes, it’s clear at our sites that these plants are investing a lot of energy in the other form of reproduction! Continue reading

A walk “in the grass”

Rob Diaz de Villegas WFSU-TV


Last week we had a post on what it was like on an oyster reef, the idea being that many people have never really seen one.  Continuing with that theme, I thought it might be interesting to take a closer look into a salt marsh.  This is a trickier proposition because, well, what is a typical salt marsh?  Some of them grow in muddy waters next to oyster reefs, or they can be found along beaches, in wide expanses or in small islands just off the coast.  I’ll keep today’s imaginary journey confined to marshes in St. Joseph Bay, where Randall Hughes conducts her biodiversity study- that is what I am most familiar with.

Continue reading

Eating contest: grasshoppers vs. snails

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biodiversity 150One of the really interesting aspects of the marsh community is that it is a mix of sea-based and land-based critters. At low tide, insects and rodents move in, whereas at high tide, snails, fish, and crabs dominate. The 2 most common plant grazers at our sites illustrate this dichotomy :

one is a land-based grasshopper(Dicromorpha elegans),


and the other is a sea-based snail (Littoraria irrorata).


In addition to being very abundant in our sites, the grasshoppers and snails leave distinctive grazing marks that alert us to their activity. Grasshoppers tend to chew large pieces out of the margin of the leaves, often resulting in the removal of large portions of the upper leaves. Snails, on the other hand, create razor-blade like incisions in the middle of the leaf:

grasshopper grazing 2

spartina with grasshopper grazing damage

Snail grazing scar

periwinkle grazing scars on spartina

We are interested in the potential for interactions between these 2 consumers, because they occur together in abundance at several of our sites. A preliminary experiment last summer suggested that snails somehow deter grasshopper feeding, even though neither animal can directly harm the other. (In fact, as you can see from the video, sometimes the grasshoppers even hang out on the snails’ backs!) However, it is possible that snails leave a “slime” trail that the grasshoppers don’t like, or perhaps snail grazing causes the plants to produce chemicals that make it less likely that grasshoppers will eat them.


To find out more, we are repeating the same experiment (with some minor modifications) to look more closely at how much snails and grasshoppers eat when they are alone versus how much they eat when they are together. Because it is difficult to make grasshoppers stay where you want them, we are doing the experiment in mesh cages inside “mesocosms” (science-speak for large buckets) at the FSU Coastal and Marine Lab.

The mesocosms are set up to mimic the natural tidal cycle, with both high and low tides on a regular basis. We measured the height and number of stems of all the plants in each mesocosm at the start of the experiment, and we’ll take these same data at the end of a couple of weeks to see which species has the largest effect, and whether their combined effects are different from what we expect based on what they eat alone.

As an aside, this experiment is a good example of one of my ecologist’s rules of thumb: you can never do an experiment just once. There are certainly exceptions to this rule. (For example, when you have lots of experience with the animals you are experimenting with, when the experiment is just too large to repeat, or when the experiment relies on something you can’t manipulate, such as an oil spill.) However, I find that it generally takes one go-around to work out the kinks, figure out the relevant time frame, and discover unanticipated results. Then I can be much more confident the second time around that the patterns I am seeing are real!

The music in the piece was by Ric Edmiston.  We are always looking for local musicians to score our videos.  If you are interested and already have some music recorded, we would love your submission.

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

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What were we doing before Deepwater Horizon?

Dr. Randall Hughes FSU Coastal & Marine Lab

Watch the “snail experiment.”
Snails in the marsh

Periwinkle snails climbing on cordgrass

IGOR chip- biodiversity 150One of the marsh animals that we have been studying for the last year (in the absence of oil) is the marsh periwinkle, Littoraria irrorata. This snail is very abundant in many marshes and is particularly visible at high tide when it climbs the plant stems to get out of the water and away from its predators, primarily crown conchs and blue crabs.

While hanging out on the cordgrass stems, the snails will often create grazing scars that look much like a razor blade cut through the grass. Even though they don’t remove much plant tissue, they can have a big impact – fungus colonizes their grazing scars, and if the fungus becomes abundant enough, it can kill the entire plant, leading to marsh loss. (See the excellent work done by Brian Silliman at UF on this topic.)

One of the interesting aspects of many Panhandle marshes is that needlerush, a taller plant than cordgrass that usually occurs closer to land, can grow side-by-side with cordgrass at the water’s edge.

When needlerush is there, lots of snails climb on it despite the fact that they don’t eat it. (We think they like needlerush because it is taller and provides a better escape from predators than cordgrass.)

Because we noticed that the cordgrass that occurs with needlerush is taller and healthier than cordgrass that occurs in patches by itself, we are currently conducting an experiment to see if this pattern is due to the snails spending less time on cordgrass when needlerush is around. Each experimental plot is surrounded by a cage that serves to keep snails either in or out so that we can test their effects on the plants. You may notice the snails are very fashionable – we ‘tag’ them with nail polish so that we can differentiate the ones we put in the cages from ones that get in from the surrounding marsh. Some cages contain cordgrass only, whereas others contain a mix of needlerush and cordgrass. Finally, in some of the cages we have clipped the above-ground portions of all of the neighboring plants – this allows us to see whether the cordgrass simply prefers the environment that needlerush grows in, or if the needlerush must be present for the cordgrass to benefit.

As long as our experiment isn’t prematurely interrupted by oil, then we should have an answer to our question by the end of the summer!

Randall’s research is funded by the National Science Foundation. The song used in the video is Florida Breeze, by Craig Reeder.

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The unsung heroes of the muck

Roberto Diaz de Villegas WFSU-TV

photo by John Spohrer

Let’s talk about the little guys.

Think a little smaller than this pelican here.  Obviously, pelicans are a symbol of our coastal areas, flying in those long rows as they do while we’re driving down Highway 98.  Pelicans covered in oil have become the poster-species of the environmental toll of the Deepwater Horizon oil spill.  It’s horrifying to think of animals as evolved as dolphins washing up on the shores, and people of course are always concerned about sea turtles.  As they should be.  They are all important parts of the Gulf ecosystem.

But they are not the only important parts.  There are other creatures that probably won’t make it on to that oil spill tragedy poster because, let’s face it, they already live in muck.  Those are the species that we’ve been most concerned with on this site.  They are worth worrying about, and I’ve come to find them cute in their way.  I keep thinking I need to try to get Disney to make a movie based in a salt marsh or oyster reef, where mud crabs and periwinkle snails sing and hide from predatory blue crabs (who, like those sharks in Finding Nemo, might be sympathetic characters themselves).  When kids are carrying plush fiddler crab dolls, maybe the little guys would get some consideration.  As it turns out, however, I have no pull at Disney.  So I’ll just talk about them right here on this blog.

Like the fiddlers.  They eat sand.  They shovel it in their mouths with their smaller claws, while they do the mating dance for which they’re better known with their larger “fiddle” claws.  I see thousands of them at a time in a salt marsh, always scurrying away and making that sound, a little bit like trickling water and a little bit like tiny bubble wrap being popped.  Of what importance are these silly little guys?

Fiddler on marsh 2

Fiddler crabs are crucial to the survival of a salt marsh

Other than being food for blue crabs, their importance has to do with the muck in which they live.  They live in the sediment collected by the cordgrass root system; you can see the holes they call home throughout the marsh.  As Dr. Hughes explained in this video, these burrows provide oxygen to the soil in which the cordgrass grows.  So their presence helps the cordgrass grow, just as the cordgrass provides them shelter.

So maybe the fiddler crab hasn’t found himself at the center of any teary oil spill montage.  But he’s an animal, and a fairly popular pet.  Spartina alterniflora- aka smooth cordgrass- may never gain a foothold in the popular imagination proportionate to its ecological importance.  It is the foundation species of a Gulf salt marsh.  These marshes act as a filter for pollutants flowing into the ocean, protecting important estuaries such as those at the mouth of the Apalachicola River.  Marshes provide shelter to a number of commercially important species (shrimp, mullet, and blue crab, for instance).  And marshes also help absorb storm surges and prevent erosion.

Those are just a couple of examples.  There are, of course, more.  Tasty, tasty oysters filter water and prevent algal blooms lethal to other species.  Toadfish have faces even other toadfish may not love, but they eat animals that would decimate oyster reefs if left unchecked.  Those oyster predators are interesting as well.  Mud crabs might get as large as 4 cm and have these thick little claws which tear through oyster shells.  Oyster drills are small snails whose tongues (radula) are covered with thousands of small razor-like teeth.

As we move forward with this project, we’ll see more and more of all of these coastal denizens.  So far oil has not reached the areas Dr. Hughes and Dr. Kimbro are studying, and so there is always hope that they may be spared.  If oil does arrive, many of these species could be severely affected.  And while some of them may not look like much, the harm that would come to them would have repercussions felt beyond their own habitats.


This snail lives on an oyster reef

Interested in seeing a fiddler crab plush toy as a WFSU-TV pledge premium?  Well, that isn’t likely to happen. But we will take comments and questions, as usual.