Tag Archives: Florida State University

Experimental spat tiles, open, closed, and partially open.

Fear and the Choices Oysters Make

Last week, Dr. David Kimbro broke nutrients and oysters down for us.  But what if oysters are too scared to eat the nutrient fed plankton they need to survive?  David and Randall take us another step closer to understanding the Ecology of Fear, examining oysters’ choices and how their behavior affects the important habitat they create.  Stay tuned over the following weeks as they unravel the relationships between predators and prey on oyster reefs and their neighboring coastal ecosystems.  We’ll also continue to follow David’s crew in Apalachicola, Hanna and Stephanie, as they research the oyster fishery crisis.

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip_ predators_NCE 150I recently moved and was faced with the dilemma of finding a place to live. This can be a touch decision, especially when you’re in a new city or town. Which neighborhood has the best schools? The best coffee shop? Friendly neighbors? Low crime? My solution was to find something short-term while I scope the place out some more, and then I can decide on something more permanent. (As anyone who has me in their address book knows, “permanent” is a very relative term – I have changed residences a lot over the last 15-20 years!) But imagine you had just one shot – one, for your whole life – to decide where to settle down. Talk about a tough decision! That’s what oysters have to do, because once they settle down and glue themselves to their location of choice, they don’t have the opportunity to move around any more. So how do they decide?

This oyster shell, harvested from an intertidal St. George Island reef, had been settled by multiple young oysters called spat. Spat grow into mature oysters with a hard shell, fused with the oyster on which they originally landed. Clumps of attached oysters form a crucial coastal habitat.

It turns out that oyster larvae (baby oysters swimming in the water) can use a number of “cues” to help them in the house-hunting process. First of all, they can detect calcium carbonate, the material that makes up oyster shells (and other things) – if there’s lots of calcium carbonate in an area, that could be a good sign that it’s an oyster reef. (Or it could be a sign that people have put a lot of cement blocks in the water in the hopes that oysters will settle and create a reef – that’s how a lot of oyster restoration projects are started.) Some recent research even shows that oysters can detect the sounds of an oyster reef, and then swim in that direction! Maybe these guys are smarter than we think…

Regardless of how oysters decide, there are times when we are also faced with the question of what makes good oyster habitat, or deciding which area is better than another. As scientists, we turn to experiments. One type of experiment that we have perfected over the years involves getting juvenile oysters- (either from the field, which can be pretty difficult -as you can see from the first round of our tile experiment, or from a hatchery), and gluing them to portable sections of “reef” (ceramic tiles weighed down by bricks). LOTS of ceramic tiles and bricks. We’re talking 800+ ceramic tiles and 700+ bricks last summer alone! That’s enough to make a path that is ~2 football fields long. All moved by truck, hand, boat, hand, kayak, and hand to their temporary location on a reef (and then moved back again when the experiment is done). But I digress.

In the second incarnation of the tile experiment, oyster spat were attached to tiles with an epoxy used in the repair of boat hulls. The tiles in the first version- the ones in the video above- were assembled differently. In a video we'll premiere later this month, we'll look at the twists and turns the experiment took.

After attaching the juvenile oysters to the tiles with a lovely substance known as z-spar, we enclose some tiles in cages to protect them from oyster predators, and we leave others with no cage so they are “open” to predators. (There’s also a 3rd group – the “cage control” – that get 1/2 a cage so we can test whether the cage has effects on the oysters other than keeping out the predators.) Then we take our oyster tiles and put them out in the field at different sites that we want to test. By observing the survival and growth of the ones in the cage (where no predators have access), we can get a general sense for whether it’s a good environment or not. Lots of large, live oysters are a sign of a good environment – plenty of food, good salinity (not too salty or too fresh), good temperature, etc. Also, by comparing the survival of the ones in a cage vs. not in a cage, we can get an idea of how many predators are around – lots of live oysters in the cage and none out of the cage is a pretty good sign that oysters are getting eaten. (If oysters in the cage are dead and oysters outside of the cage are missing, it’s a little tougher to figure out exactly what’s causing it, but it’s clearly not a good place for oysters to live!)

Experimental spat tiles at the Guana Tolomato Matanzas National Estuarine Research Reserve- open, closed, and partially open.

Of course, the oysters themselves don’t know whether they are nice and safe inside our cages, or easy pickings for a predator. So if there are lots of predators lurking around the reef, the oysters may try to “hide”. Obviously, hiding for an oyster does not mean packing up and moving elsewhere, but they do have a few tools at their disposal. In the short term, the oysters can choose not to open up their shells and feed (filter water) as often. This strategy has 2 benefits – 1, they are less vulnerable to predators when their shells are closed and 2, they aren’t releasing lots of invisible chemical cues in the water when they’re closed, so it’s harder for the predators to tell they are there. But as any of you who have been sticking to your New Year’s resolution to lose weight will know, there’s only so long that you can go without eating before that strategy loses its appeal! Over the longer term, the oysters can decide to devote more of the energy that they get from eating to create a thicker, stronger, rougher shell, rather than plumping up their tissues.

So, those are the big-time decisions that an oyster faces: where to live, and when to eat. Sounds kind of familiar…

We want to hear from you! Add your question or comment.

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

Over 60 milk jugs from a Tallahassee Starbucks.  Good use of recycled materials, but will it float?

Whatever Floats (We Hope) Your Boat

Rob Diaz de Villegas WFSU-TV


Over 60 milk jugs from a Tallahassee Starbucks. Good use of recycled materials, but will it float?

Today we take a little break from the Apalachicola River and Bay crises and from our ecological explorations into the intertidal for something fun: The FSU Coastal & Marine Lab’s 1st Annual Regatta.  People from the community, many wearing outlandish costumes, brought in seven different homemade boats made from recycled materials.  I was mentally prepared to film sinking ships (and half of them tested their boats ahead of time) and rescues from the two rescue boats stationed at either end of the course.  It was as entertaining a shoot as I’ve been on recently, and it could have been a longer segment if I’d included the explanations of each boat name, which were typically pretty clever.

In the interview with Dr. Felicia Coleman, she mentions that she wanted to bring attention to recycling.  It’s not as hot button an issue as climate change, the BP spill, or water management in the ACF basin, but a few stats gathered by In the Grass, On the Reef Associate Producer Rebecca Wilkerson illustrate that if we as a society recycled more of our plastic, we would be doing our oceans a favor.

The "Splinter," a boat made from a kiddie pool and various plastic recyclables, wrapped in plastic and shaped like a turtle. Who can identify which turtle each girl is supposed to be from their painted on masks?

Over 300 million tons of plastic are produced every year.  Sources gathered by Rebecca indicate that only 5-10% of it is recycled.  The rest ends up in landfills and in the ocean.  There is no definitive number on how much plastic is floating in the ocean.  The State of the Planet blog from Earth Institute at Columbia University puts the number in the hundreds of million of tons, where a more ambitious attempt at calculating it from 5GYRES puts it at 315 billion tons.  This page on the Marine Research Institute’s Algalita web site discusses how slowly plastic breaks down, possibly staying in ecosystems for centuries.  Plastic floating near the surface confuses birds and gets eaten by them.  Properly disposing of plastic would is the best way to prevent this burden on our oceans.

Well, there I went getting serious when I said we were taking a break from the serious.  I hope you enjoy the video.  In the next few weeks we’ll delve back into the intertidal, looking more closely at some of the ecosystem services provided by salt marshes and oyster reefs.  And we’ll be posting two video segments from RiverTrek 2012, so stay tuned!


Four Ways (and more) That Salt Marshes Earn Their Keep

Episode 5: The True Value of a Salt Marsh

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- habitat 150IGOR chip- sedimentation 150IGOR chip- filtration 150IGOR chip- human appreciation 150

Much like David finds it hard to distill why the oysters that he studies are so intriguing, I often struggle to convey the charisma of the salt marshes and seagrass beds where I spend so much of my time. At least people like to eat oysters! It can be harder for people to find a connection with the plants that form so many of the critical habitats along our coast (unless of course people misunderstand the meaning of “In the Grass” and think I study a VERY different type of plant!). But even if it is not recognized, there is a connection between the salt marsh and our everyday lives. Like oyster reefs, salt marshes provide many benefits to society, particularly along the coast:

1. A place to live (for marine and terrestrial animals)

Periwinkle snails are among the many animals that make use of the salt marsh habitat.

Even if you’re one of those folks who find it hard to get excited about a bunch of plants, don’t tune out – the salt marsh is teeming with animals! Snails, fiddler crabs, mussels, grasshoppers, dragonflies, and snakes (!) are all critters that we encounter regularly when the tide is out. And there’s always a bit of an adrenaline rush when you see an alligator hauled out nearby. Even better, when the tide comes in, there are lots of animals that you and I (or at least, I) like to eat. Think blue crabs, mullet, and sea trout, for starters. Studies in Florida estimate that marshes provide up to nearly $7000 per acre for recreational fishing alone. Not bad.

2. A safer place to live (for people)

Although it’s generally frowned upon to build houses in the marsh (since it makes it hard for all those animals I just mentioned to live there), it’s a great idea to have lots of healthy marshes near your coastal property. Marshes can protect the coastline from waves and storms, leading to less damage in areas with marshes present. One estimate places the dollar value of coastal protection in the U.S. at over $8000 per hectare per year in reduced hurricane damages! Although here’s hoping that we don’t get an opportunity to test that particular benefit this year.

In addition to reducing the size and strength of waves, marshes also prevent coastal erosion. An unfortunate example of the role of marshes in erosion control came following the Deepwater Horizon oil spill – plants in areas of the marsh that were heavily oiled died, leading to greatly increased rates of erosion in those areas (Silliman et al. 2012). Although the benefit of marshes for reducing erosion and combating sea level rise has been recognized for a long time, there are not any good estimates for what this erosion control is worth in $$. Given expectations of sea level rise in the coming years, I think that the motivation to understand the conditions that lead to sediment accumulation in marshes will only get stronger.

3. Clean water (for animals and people)

Because marshes lie at the intersection of the land and the sea, they serve as a filter for things trying to move between the two. When it comes to run-off and pollution from the land, it’s a very good thing that they do. Simply having a marsh present can serve as an effective alternative to traditional waste treatment. Of course, the protection can go the other direction too – marshes played a critical role in keeping oil from the Deepwater Horizon oil spill from getting to higher elevations.

4. A place to graze (for livestock)

Support for livestock grazing is an important role of marshes in some areas, including the U.K. Although it’s not a benefit commonly associated with marshes in this area, the decaying fence posts that extend out into some areas of St. Joe Bay suggest that it wasn’t too long ago that marshes were used for a similar purpose here!

I could go on, but these and other benefits of marshes are described in greater detail in a recent review by Barbier and colleagues (which I referenced on this blog in May of 2011). Here is the table that they put together summarizing the monetary benefits that we derive from intact salt marshes:

Luckily for us, salt marshes keep working their magic even in the absence of accolades or appreciation. But greater appreciation is needed to help curb the decline of salt marshes around the world – estimated to be as much as 2% per year! We hope that this blog will help generate greater understanding and enthusiasm for the incredible coastal habitats that we are lucky enough to work in every day. Let us know how we’re doing!

In the next two weeks, we delve into a habitat that we have only occasionally covered: seagrass beds.  Next week we examine, with visiting researcher Dr. Peter MacReadie, seagrass beds’ role in fighting global climate change.  The week after that, we head to Bay Mouth Bar, one of the most ecologically unique places in the world.  Also, we’ll be look at the failure of the Apachicola Bay oyster reefs from a biological perspective.  Here are a few images of our visit to a Saint Joseph Bay seagrass bed and of Bay Mouth Bar at low tide, when you see all kinds of strange and interesting creatures:

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

Music in the piece by Kokenovem and Pitx
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.


The Combined Benefits of Research and Teaching

Dr. Randall Hughes FSU Coastal & Marine Lab

I recently completed teaching a 2-week course in Field Marine Science at FSUCML. Nine undergraduate students and one graduate teaching assistant lived in housing at the lab for the duration of the course, and we were busy from virtually sun-up to sun-down each weekday with class activities. It was a lot of fun:


The students of Field Marine Science 2012 inspect what we caught trawling through a local seagrass bed.


A group of students works to complete our field survey before the sun sets.


Students hunting for mud crabs for a lab mesocosm experiment.

This year, we focused on oyster reef ecosystems, taking advantage of past and ongoing projects in the Hughes and Kimbro (aka, “Hug-bro”) labs. We conducted a field experiment, field survey, and mesocosm experiment examining sediment accumulation on oyster reefs – and all in just 2 weeks!


Students quantify sediment accumulation on oyster shells during our field experiment.


Students process the contents of cages from our field experiment, looking for crabs.

Well, the field experiment and survey were started ahead of time by Hugbro personnel, but the labor-intensive breakdown and sample processing tasks were handled by the class.


Surveying mud crab abundance on our experimental reefs.

After all that time spent learning about, walking around on, and handling oysters, everyone was ready to eat a few by the end of the second week!


An underwater camera gave us a great view of the seagrass!

In addition to gaining hands-on research experience, a goal of the class was to become familiar with common coastal habitats in northern FL. So we squeezed in a few trips to seagrass beds and salt marshes as well, enjoying the opportunity to ride on a boat that didn’t require paddles.


Happily preparing to snorkel in St. Joseph Bay State Park, FL.

We observed lots of sea hares as we snorkeled in St. Joe Bay.

And we were all happy to don snorkels and masks to explore the seagrass instead of gloves and boots for the oysters!


Results of a study by Feldon and colleagues demonstrating an increase in the quality of hypotheses included in graduate student research proposals when the students had teaching responsibilities.

As I catch up on the research projects that languished a bit while I was teaching, it is reassuring to think about the results of a recent study illustrating that teaching can increase the quality of research. Don’t get me wrong – I enjoy and value teaching for its own sake – but the tasks of teaching and research can often seem in competition with one another when time is limited (and when is time not limited?).


Additional results from the study by Feldon et al. showing better experimental design in research proposals written by graduate students that teach and do research.

Enter the study by Feldon and colleagues in the journal Science, showing that graduate students with teaching responsibilities formed better hypotheses and generated better experimental designs in their own research proposals than graduate students without teaching responsibilities. This benefit did not result from explicit instruction in hypothesis testing or experimental design geared towards the graduate students themselves – rather, the process of teaching scientific concepts to others made them better able to conduct research. So add to the inherent fun and satisfaction of teaching a boost to my research! Time to write a (better?) research proposal…


Pea crabs at various stages of development. The ones in the center are young crabs, as they appear in the stages immediately following infection of an oyster. The ones on the right are older, harder-carapaced crabs (most likely males, which may leave their hosts in search of oysters harboring females). The crab on the left is a mature female. The developing, orange-colored gonads are visible through the female’s thin carapace. Since mature females never leave the their host oyster, their carapaces (shells) are very soft and thin. This makes them very… squishy and pea-like.

Pea Crab Infestation!

Tanya Rogers FSU Coastal & Marine Lab

IGOR chip- biogeographic 150Serendipitous results are surely one of the most rewarding parts of experimental research. This past winter, I spent many weeks processing various frozen components of great cage experiment of last summer, including the several hundred spat tiles placed inside the different cages at all sites along the coast. It was while delicately measuring and shucking these little spat that I made one such unanticipated finding: Our oyster spat, unbeknownst to us, had become infested with pea crabs.

Pea crabs at various stages of development. The ones in the center are young crabs, as they appear in the stages immediately following infection of an oyster. The ones on the right are older, harder-carapaced crabs (most likely males, which may leave their hosts in search of oysters harboring females). The crab on the left is a mature female. The developing, orange-colored gonads are visible through the female’s thin carapace. Since mature females never leave the their host oyster, their carapaces (shells) are very soft and thin. This makes them very… squishy and pea-like.

You might have had the surprise of finding an oyster pea crab (Zaops ostreus) while shucking an oyster yourself. These small crabs live inside oysters and are a type of kleptoparasite, meaning they steal food from their hosts. An oyster gathers food by filtering water over its gills, trapping edible particles on its gills, and carrying those particles to its mouth using cilia (tiny hairs). Pea crabs sit on the gills and pick out some of the food the oyster traps before the oyster can consume it. By scurrying around inside oysters, pea crabs can also damage the gills mechanically. The pea crabs, like most parasites, don’t kill their hosts, but they can certainly affect the oysters’ overall health.

pea crabs 2

A gravid (egg-bearing) female pea crab next to the oyster spat in which she was living. The female, like most crabs, carries her eggs until they hatch, and then releases her larvae into the water. The baby crabs, when ready, will locate a new oyster host by smell.

As I was processing the oyster spat from all of our experimental sites (Florida to North Carolina) for survivorship, growth, and condition, I began to notice a surprising number of pea crabs living inside them and started to keep track. What’s interesting was not so much that the oysters had pea crabs, but that the percentage of oysters infected with pea crabs varied geographically. For instance, only about 25% had pea crabs in St. Augustine, Florida, whereas over 70% were infected at Skidaway Island, Georgia. Keep in mind that these spat all came from the same source and the same hatchery, so they all had the same starting condition. What’s more, I found that spat in Georgia which had naturally recruited to the tiles from the surrounding waters (of which there were quite a lot, and for which I also processed condition) rarely had pea crabs. Only about 5% of the recruits had pea crabs at Skidaway Island, Georgia. Why is there this huge difference in infection rate? Do the local oysters know something that the transplants don’t? How do these patterns in pea crab infection relate to other geographic patterns we’re finding? How does pea crab infection affect oyster condition? These and many more questions await to be addressed in further analyses and future experiments.

In the Grass, On the Reef, A World Away

Dr. Randall Hughes FSU Coastal & Marine Lab

IGOR chip- biogeographic 150IGOR chip- habitat 150David and I are in Sydney, Australia, on visiting research appointments with the University of Technology Sydney. We arrived the first of the year, and after recovering from jet lag and getting our bearings, we embarked this week on setting up a couple of new experiments.  We have great local “guides” – Dr. Peter Macreadie (UTS), Dr. Paul York (UTS), Dr. Paul Gribben (UTS), and Dr. Melanie Bishop (Macquarie University) – to introduce us to the field systems and collaborate with us on these projects.


Our seagrass and razor clam experiment is set up at Point Wolstoncroft in Lake Macquarie (north of Sydney).

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Photo feature: Oyster Love

From the FSU Coastal & Marine Lab

IGOR chip- human appreciation 150What’s not to love about oysters? They clean the water, they’re delicious, and they have surprising economic value. Members of the Kimbro Lab found this unique oyster, which itself seems very loving, on one of their study sites. “Now I’ve seen a lot of weird-shaped oysters,” says lab tech Tanya Rogers,” but never one quite this perfect. I took it on a photoshoot this evening for some nice background and lighting.”

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.

Spat on a Platter

Tanya Rogers FSU Coastal & Marine Lab

IGOR chip_ predators_NCE 150“Spat tiles” are a tool our lab commonly uses to measure the growth and survivorship of juvenile oysters under different conditions, and we’ve used them with varying degrees of success in many of the experiments chronicled in this blog. What these are essentially (in their final form, after a good degree of troubleshooting), are little oysters glued to a tile, which is glued to a brick, which is glued to a mesh backing, which is zip tied vertically to a post. Rob and I have put together a couple interesting slideshows chronicling the growth of these spat over time from two of those experiments. Ever wonder how fast oysters grow? Observe…

This is a time series from our first spat tile experiment, which you can read about in this post. As you may recall, this experiment was largely a failure because the adhesive we used to adhere the spat was inadequate. However, we decided to keep the fully caged tiles out on the reefs to see how they fared over time in different locations. I photographed the tiles every 6 weeks or so, so that we now have a series showing their growth over time. The slideshow shows one of the tiles from Jacksonville. It starts in October of 2010. You’ll notice that not much growth occurs though the late fall and winter, but the spat start to grow noticeably from April-June 2011. From June-September the spat grow explosively and many new spat settle on the tile from the water column and grow equally rapidly. Just as plants (and algae) have a summer growing season, so too do the oysters that feed on them, when conditions are warm and there is abundant phytoplankton in the water to eat.

Next is a series of images from our caging experiment last summer, which you can read about here. Our large cages contained either:


no predators (bivalves only),


spat-consuming mud crabs and oyster drills (consumers),


or mud crabs and oyster drills plus blue crabs and toadfish (predators).

The spat tiles within the larger cages were placed either exposed to potential predators or protected from them in a smaller subcage. Here are typical examples of what tiles looked like at the end of the experiment (about 2 months after starting). You can see how all the spat on the unprotected tiles were wiped out in the consumer treatments, but a good number survived in the treatments with no predators, as we would predict. In the predator treatments, most of the spat on unprotected tiles were removed, but not as fully or quickly as in the consumer treatments, which we would predict if the predators are inhibiting consumption of spat by the mud crabs and drills through consumptive or non-consumptive effects. You’ll see one tiny spat holding on in the predator tile shown. On the protected tiles, most of the spat survived in all treatments, as expected. We plan to further analyze the photographs from the protected tiles though, to see whether spat growth rates differed between them. We may find that protected spat in the consumer treatments grew slower than in the other treatments because of non-consumptive predator effects.

Currently, we’ve recovered most of our arsenal of spat tiles from the field, and I say we have probably amassed enough bricks to pave an entire driveway! Good thing we can reuse them!

The Biogeographic Oyster Study is funded by the National Science Foundation.