Dozens of different mollusk species interact within a relatively small area at Bay Mouth Bar, from all manner of bivalves to the predatory snails that eat them (and each other).
As soon as you arrive to BMB, it is easy to imagine and feel the same curiosity and fascination that Robert Paine brimmed with when he first immersed himself in the sand bar fifty years ago.
If someday you have the opportunity to visit BMB at low tide, then you would receive much pleasure in looking at 40000 m2 of sand, full of awesome critters! Twenty minutes by kayak, that’s it!
Since I started working at FSU’s marine lab, I have frequently cast longing looks at a local study system that hasn’t been examined in over 50 years. Back in the 1960s, the world’s most famous ecologist (Bob Paine) was a post-doctoral researcher working at FSU’s Marine Lab. It was at this time and place where he began developing some of the concepts that would transform the field of ecology. Continue reading →
A listing of the animals seen in the slideshow is at the end of this post.
March is Seagrass Awareness Month, so it seems a fitting time to share some photos we took last fall. Seagrass beds are an under-appreciated habitat; they’re very productive and are more important than meets the eye (here I admit that neither seagrass beds or salt marshes seemed all that interesting to me until I actually went into them and took a closer look). Here are a few quick facts: Continue reading →
A sure sign of spring for me is an increase in time in the field. (Robyn and Emily would probably disagree with me, since they have been out in the field regularly throughout the winter!) I have been in the lab or office since December, which feels like a long time, and I’m really looking forward to getting back in the field. I find it is so much easier to come up with new research questions and develop insights into what the animals and plants are doing out there when I’m actually there with them. I guess that makes sense!
David's collaborators, from left to right- Dr. Jeb Byers, Dr. Mike Piehler, Dr. Jon Grabowski, and Dr. Randall Hughes.
As you can see from the video that summarized our efforts over 2010, it was a busy 6 months of research. After taking a great break during the holidays, the entire oyster team (Jon = Gulf of Maine Research Institute, Mike = University of North Carolina at Chapel Hill, Jeb = University of Georgia, Randall = Florida State University and me) met for a long weekend to figure out what we accomplished and where we are going in the future.
You might think that our 2011 research plans should already be set given that we received funding. Well, we did receive funding to carry out some outlandish field experiments in 2011, but these experiments were dreamed up in our offices and may not address the most ecologically relevant questions for our system. Checking in with the monitoring data is probably the best way to determine if our planned experiments were on target or if they needed to be adjusted and hopefully simplified!
Prior to the oyster summit last weekend, I hounded all of the research teams for all of their data. Given the huge volume of data and everyone’s busy schedules with teaching classes and other research projects, this was quite the task. Once Tanya meshed all the data together (also not a simple task), I then moved on to the next task of analyzing our data.
Well, the initial excitement quickly turned into a stomach churning feeling of….where the heck do I begin? Similar to the way that too many prey can reduce the effectiveness of predators, the data were swamping me…I was overwhelmed and the draining hourglass wasn’t helping (people were flying into town in two days…yikes!).
After multiple cups of coffee, the anxiety passed and I decided to revisit some basic questions:
David's team used gill nets to catch the larger fish around the reefs, many of which are top predators in that habitat.
(1) With the gill nets, we obtained predatory fish data. So how do the abundance and biomass of these fishes vary across latitude? And does this pattern change with season (i.e., summer versus fall)?
(2) Then I thought back to the fond memories of ripping up oyster habitat to check out the abundance of things that consume oysters (e.g., mud crabs). Oh…the memory of that work gives me a warm and fuzzy feeling; I bet Tanya, Hanna, Linda and everyone else that helped feel the same way! How do the abundances of these things change across latitude? Are there larger crabs up north or down south? How does the mud crab picture mesh with the predatory fish picture?
This spat stick is made of calcium carbonate, the same substance as oyster shell, and is ridged to simulate the ridges in those shells. That makes it an attractive landing spot for oyster spat (larval oysters), which tend to settle on oyster shells.
(3) Working our way down the food web and sticking with the oyster samples we ripped up back in August, how do oyster densities and oyster size change across latitude and how do these patterns mesh with the mudcrab and predatory fish data?
(4) Finally, I wanted to revisit the data from our instrumentation to see how temperature and salinity changed across latitude and with season, as well as the data from our spat sticks to see how oyster recruitment differed.
It’s pretty amazing that six months of work can be summarized so quickly into four topics. Well, I kept hitting the coffee and got all of these data worked up in time for the first portion of our oyster summit. Surprisingly, all inbound flights arrived on time and we all assembled last Friday to go over the data. I’ll briefly lift the research curtain to illustrate what our data looked like:
The Georgia reef gill nets trapped a lot of sharks. Here Dr. Jeb Byers is removing blue crabs (also an oyster reef predator) from shark bellies. The trapping done on these reefs is clarifying the food web for these habitats.
(1) Although we predicted predator abundance to increase at lower latitudes, predator abundance and the number of different predators peaked in Georgia/South Carolina. This is because lots of the species we have in Florida were also in Georgia. And, Georgia has lots of sharks! Needless to say, Jeb’s crew has been the busiest during gillnet sampling. Jon and Mike’s crew have had it pretty easy (no offense)! The workload reduced for everyone in the fall, but the differences across latitude stayed relatively the same. The really cool result was the pattern that hardhead catfish are extremely important and the most abundant predatory fish on Florida reefs; I love those slimy things.
(2) Interestingly, mudcrab biomass peaked up north where predatory fishes were less abundant.
(3) And the abundance of large, market size oysters was highest where predatory fish were most abundant (GA/SC).
(4) Amazingly, we all did a good job selecting oyster reefs with equivalent salinities (this can vary a lot just within one estuary) and temperature was the same across all of our sites until December….instrumentation up north got covered in ice! Glad I was assigned the relatively tropical reefs in Florida. Finally, oyster recruitment in NC and Florida appears to proceed at a trickle while that of GA/SC is a flood-like situation during the summer.
A month after first being deployed, Tanya and Hanna inspect an Alligator Harbor tile. You can see that some of the oysters have definitely started growing, but also that some of the spat became unglued. When they run the experiment again, they'll use a different adhesive more suitable for a marine environment.
After we all soaked that in, we then talked about the tile experiment. While these data were really cool (mortality presumably due to mudcrabs was lowest where predatory fish were most abundant = GA), we worried about being able to tease apart the effects of flow, sedimentation, and predation. Unfortunately, this experiment seems to uphold my record with experiments: they never work the first time. We’ll probably repeat this in fall of 2011 with a much better design to account for flow and sedimentation.
Before breaking for a nice communal dinner at my place, Mike summarized the nutrient cycling (sediment) data that we have been collecting. In short, having lots of living oysters really promotes de-nitrification processes and our sampling picked this up.
Putting this all together, it looks like there are latitudinal patterns in fish predators that may result in mudcrab density and size patterns. Together, these may help account for latitudinal patterns in oysters (highest in GA). This all matters because more oysters = more denitrification = healthier estuarine waters.
END DAY 1
On day 2 of the summit, we worked through what made us happy about the monitoring data, what things we could add on to make us happier, and that we should continue this monitoring through the summer of 2011. This actually took all morning.
On day 2, the oyster summit moved into the more comfortable location of the Marine Lab guest house.
After a quick lunch break, we then reconvened in another room with a better view (nice to change up the scenery) to go over how we should experimentally test the linkages I mentioned above. This is where the saw blade of productivity met a strong wood knot. Personally, I became horribly confused, fatigued and was utterly useless. This resulted in lots of disagreement on how to proceed and possibly a few ruffled feathers. But nothing that some good food and NFL playoff football couldn’t cure.
After taking in a beautiful winter sunset over the waters off the lab, we ditched the work and began rehashing old and funny stories about each other.
Amazingly, we awoke the next morning and fashioned together a great experimental design that we will implement beginning June 2011. To Jeb’s disappointment, this will not involve large sharks, but we will get to play with catfish!
But now it’s time to prepare for our winter fish and crab sampling. It will be interesting to see what uses these reefs during the dark and cold of winter!
Thanks for following us during 2010, and please stick around for 2011 as I’m sure things will get really interesting as we prepare for our large field experiment.
David’s research is funded by the National Science Foundation.
Emily and Hanna, in matching green waders, vacuum bugs on "Island 4."
It has been COLD the last few times we’ve been out in the field. The first time (described accurately by Rob), we did not have sufficient cold weather field gear – David lent us some emergency use chest waders that he had on hand, and they were much appreciated despite the fact that we looked really silly and they were all split open at the feet by the end of the day!
Immediately upon my return to the lab, I ordered my team the trusty neoprene chest waders that I used throughout graduate school in northern California. As Emily and I can attest after going out twice more in the cold since then, they make a big difference!
Newly purchased neoprene waders and fingerless gloves for winter field work.
Aside from the change in attire, what else is different in the cold? Most obvious is that many of the cordgrass stems in our survey plots are dead. In marshes north of here, the above-ground portions of the plant will actually die back completely in the winter, re-sprouting from below-ground reserves in the spring. Here, there are fewer stems overall, and certainly fewer bright green live ones, but the plants will continue to slowly put up new stems throughout the winter.
The photos above are of Island 4 over the course of WFSU's documenting this work. The photo on the left is from May 13. The one in the center was taken at the end of Summer. You can see the grass is taller and more verdant, with cordgrass reproductive shoots popping up over the blades. The last photo is from the first of December.
The cordgrass reproductive stems are also now dead – most of them dropped their seeds in late November / early December, so they have done their job. Emily and I made a special trip to all of our survey sites a week or so ago to set out “seed traps”. And what, exactly, is a seed trap? In this case, it’s a Styrofoam bowl lined with Tanglefoot, the incredibly sticky substance that we use on our mesocosms to keep snails from climbing out.
Any seeds (or seagrass wrack, other plant material, bugs, or anything else, really) that fall into the bowl will stick, allowing us to count the number of seeds that get to each area. We are particularly interested in whether seagrass wrack abundance increases or decreases the number of seeds in an area. We’ll go back in January to pick them up and start counting.
We have some plants in the greenhouse that we’re growing for experiments this spring, and they have been getting a little extra TLC on these cold, cold nights. We cover them with frost blankets at the end of the day, and then uncover them again in the mornings when it’s warmed up a bit. They seem to like the extra warmth!
Our greenhouse tables covered in (appropriately) green frost blankets on cold winter nights.
From a logistics perspective, the winter is pretty different for a number of reasons. First, it’s harder to find people available to go in the field. (And on really cold days, it’s not very appealing!) Emily will be back on campus taking and teaching classes next semester, so we’ll probably have to do some portion of the monthly surveys over the weekend, hopefully with the help of some undergraduate interns.
Looks like we're walking.
The second logistical challenge is the change in the tides. For most of the year, the low tide is in the evening / night, so it is easiest to kayak to our sites during the morning and early afternoon. In the winter, the low tide shifts to the middle of the day, and it’s often made even lower by a strong north wind, making it virtually impossible to kayak anywhere during daylight hours!
Our solution is to walk to the sites that we can, and kayak as close as we can to the others before we start walking. It’s a good thing that St. Joe Bay is shallow!
In January, we’ll be sampling fishes and small crabs in the marsh. We do this every couple of months to see how the abundance of the more mobile marsh community members changes seasonally. I don’t expect that we’ll find much, but I’ll let you know!
Randall’s research is funded by the National Science Foundation.
I 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.
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.
One 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?
You’ve heard about research from a lab tech’s perspective from Tanya, and from a Principle Investigator (PI)’s perspective from Randall and David, so I thought I’d give you a graduate student’s insight. Being a grad student is kind of like being a mash-up of a tech, a student, and a PI: you do a lot of the “dirty work,” but you also have to be able to direct other students and manage your own research. You’re taking classes, but you’re also teaching. You’re writing grant proposals for future projects, but you’re also trying to figure out how to analyze data from past projects. And while this might sound hectic enough to create split personalities, I love it! I get to develop my own projects, take challenging and interesting classes, and help Randall with her projects. In fact, my favorite thing about work is that it’s such a tumbled mix of things: my time is split between the lab, field, classroom, and desk. Life as a grad student is never boring!
Emily and Robyn getting gear ready to collect porewater samples.
I moved to Florida in May 2009, right after graduating from University of Rhode Island, and worked for Randall as a tech before starting school in the fall. It was a great way to familiarize myself with the system and learn appropriate sampling techniques for the area. I came in thinking that I wanted to work with epiphytes (small seaweeds that grow on other plants/seaweed) on seagrass. I did develop a project working with Chris Stallings on his huge Big Bend survey looking at the epiphytes throughout the region, but as I was working for Randall, I became more and more interested in developing my own project in the salt marsh. I am now studying the effects of wrack in the marsh. The epiphyte project is ongoing, and a marine certificate student, Michele Sosa, took over the project this summer so that I would have more time to develop my wrack research.
I think that is one thing I’ve learned as a grad student: there’s so much you could do, that it can be hard at first to pick one thing to develop into an interesting and informative project. If you’re not careful, you might end up with a bunch of semi-related “side projects.” I definitely owe Randall a lot for helping me stay focused and develop a clear project with a solid theoretical basis. As Tanya said, when there is a lot of work to do, it’s easy to get bogged down in the details and forget the big picture –which you definitely can’t do when you’re in charge of the project!
Dr. Randall Hughes and Emily Field.
The other trick to grad school is balance, which can have a steep learning curve! One of the first things they tell you when you enter school as a graduate student is that you’re expected to work 60 hours a week: 20 on your coursework, 20 on teaching or your advisor’s research (depending on what you’re being paid for), and 20 on your own research. Of course, every week does not break down into this perfect division, but I think the main point to remember is to balance all of your responsibilities. Which is much, much easier said than done. As I’m writing this post, I’m thinking about the various other tasks I should probably be doing. My bugs need sorting, that paper needs reading, those buckets need mending… the list goes on. But, hey, I knew what I signed up for when I decided to go to grad school. I was warned. However, if you ever see me talking to myself, do me a favor and send for the nice men in the white coats?
Emily and Robyn setting up yet another tank experiment that I've dreamed up. (Thanks to Nancy Smith for the pic!)
Because 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!
Snails climbing on cordgrass reproductive stems in the field.
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?
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!
It’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.
This week’s videos look at Dr. David’s Kimbro’s collaborators in the NSF funded biogeographic oyster study. While he has been the face of the study for On the Reef, he is one member of a team of scientists. Today’s videos feature Dr. Randall Hughes (In the Grass) and Dr. Jon Grabowski. Later this week, we’ll have a short video with Dr. Jeb Byers. Randall and David’s posts accompanying the videos are reminiscences on their early days in marine ecology in North Carolina, where they and their fellow team members met while in school.
Dr. Randall Hughes FSU Coastal & Marine Lab
Getting my first taste of marine ecology.
In my last semester as an undergraduate at the University of North Carolina-Chapel Hill, I took a class in marine ecology from Dr. Charles (Pete) Peterson and Dr. Mark Hay.
At the time, I was a double major in biology and public policy analysis, and despite being just a few months from graduation, I was still very uncertain what I was going to do next. So when Pete asked me if I would like to work as a summer research assistant at UNC’s Institute of Marine Sciences for his graduate student, Jon Grabowski, I accepted with little idea of what I was getting myself into.
Jon’s project involved comparing the value of restored oyster reefs in different locations in the marsh (next to marsh edges, sandwiched between marsh edges and seagrass beds, or isolated on sand flats) as habitat for important fishes and crabs. What that meant in reality was that in the summer of 1997, we used ~2 tons of dead oyster shell to create 12 intertidal oyster reefs in Middle Marsh, NC – largely by carrying the shell in orange baskets from one big pile to the specific places where we needed it.
One of the reefs we built in 1997 on a sand flat, pictured here in 2002.
In the process, I learned to trailer and drive a boat, build 30+ fish traps that involved welding rebar together and dipping the whole contraption in “net dip” (the most disgusting substance known to man), deploy and retrieve those traps and happily (well, at least begrudgingly) handle the blue crabs, toadfish, and other critters that we caught, and various other tasks that made my parents wonder why I needed a B.A. degree for this job. But by the end of the summer, I was hooked!
Jon, before he was Dr. Grabowski.
After that first summer, I returned to work with Jon for 3 more field seasons until starting graduate school myself in 2000. (David and my paths crossed at IMS, working for Jon together in 1999.) During the “off-season” I taught school, first in Mexico and then in NC, because I wanted to be sure that becoming an ecologist was really the thing for me. I love teaching, but I love research even more, and so going to graduate school seemed the logical way to combine the two.
Much like the no-see-um story from Jacksonville, the long hours and hard work involved with Jon’s project generated a lore surrounding that first (and subsequent) years. Here’s just one of my favorite stories from the summer of 1997 –
Dr. Pete Peterson in Middle Marsh, NC.
Once the reefs were created (and lots of stories could be told about that process), the plan was to sample them once a month over consecutive daytime and nighttime high tides. Because we couldn’t sample all of the sites at the same time, this involved 48 hours of effort with only short breaks in between times in the field. The first time attempting this sampling happened to fall the 2 days before I was scheduled to leave to start my job teaching in Mexico – oh, and on my birthday. After day 1, we realized that returning to the lab from our field sites and then going home to get cleaned up before getting some rest was burning lots of valuable sleep time, so we decided that the second night we would camp on one of the barrier islands close to our sites. Jon packed most of the gear, including a giant and heavy cooler, and off we went. Of course, it was the middle of the night when we finished up in the field and drove the boat over to Shackelford Island, and we hadn’t bothered to set up camp earlier in the day. Jon thought he knew of a shortcut to cross over to the ocean side, which had a nice breeze and far fewer mosquitos. Unfortunately, we didn’t find the shortcut immediately, and we ended up carrying the heavy cooler and all of our other gear while swatting and cursing mosquitos for quite a while. About 5 minutes from the beach side of the island (though we didn’t know that at the time), I snapped, announcing to Jon that I was NOT walking any farther and so we better set up camp in that spot. (I had maintained a fairly mild-mannered and easy-going persona all summer, but there was nothing mild about my ultimatum that we stop walking.) I was in better spirits after a few hours of sleep, feeling more than a little chagrined at my outburst when I realized how close we were to the beach, and especially when learned that the primary object in that heavy cooler was a chocolate birthday cake for me! I have since apologized many times, and Jon and I laugh and re-tell that story virtually every time we get together.
Of course, beyond the friendships, funny stories, hard work, and good food, we also learned a heck of a lot about oyster reefs and the animals that live on and around them. That’s why our current collaboration “On the Reef” is so satisfying – it’s a way to return to our roots scientifically, professionally, and personally.
The biogeographic oyster study is funded by the National Science Foundation.