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!
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 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.)
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.
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.
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 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.
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.
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?
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.
A cordgrass reproductive stem stands above the surrounding plants.
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 →
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.
The video above is from our dimensions program. It dovetails nicely with what we care about on this site, which is the ecology of Florida’s Forgotten Coast, in this case salt marshes. The idea is that, when looking to minimize potential oil damage to our coast, you start with its smallest building blocks. Operation Noah’s Ark, based out of the Gulf Specimen Marine Lab in Panacea, is collecting a lot of little critters that live in places like salt marshes. The fiddler crab helps maintain the marsh with its burrows, which bring oxygen to cordgrass roots. In that grass, juvenile mullet find shelter, as do blue crabs and juvenile pinfish. The Kemps-Ridley Sea Turtle eats those blue crabs, and those pinfish will mature and swim out into the gulf to be eaten by gag grouper. You can see how one species becoming compromised can have a cascading effect throughout the Gulf. Continue reading →
Since my last post, oil has stopped spewing from the Deepwater Horizon well, a very welcome development in what has been a long and grim story. Although it is tempting to feel that we are out of the woods, all one needs to do is consider the amount of oil that has entered the Gulf to realize that it will be a long time before we fully understand the ecological impacts of this disaster, much less fully recover from it.
That said, the probability that the marshes I study in St. Joseph Bay and Apalachee Bay are going to be directly impacted by oil has declined dramatically. You may wonder, were our efforts to collect “pre-oil” data wasted? The answer is no, for a number of reasons:
One 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 :
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:
spartina with grasshopper grazing damage
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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