Tanya Rogers was Dr. David Kimbro’s research assistant and worked primarily on the collaborative study of oyster biogeography and ecosystem processes featured in this blog. She has a Bachelor of Science in Biology from the University of Puget Sound in Washington, and has done undergraduate research at Bodega Marine Laboratory and Friday Harbor Laboratories. She is interested in marine community ecology and conservation, as well as natural history and scientific illustration. She is now a graduate student for Dr. Kimbro at Northeastern University.
View all posts by Tanya →
A couple of months ago, we looked at the increasing number of mangroves surviving north of their range in Gulf coast marshes and wondered how it might change that habitat. On a research trip to Panama, Tanya Rogers got a good look at how mangroves interact with many species found in North Florida. There, oysters grow on trees.
Tanya RogersFSU Coastal & Marine Lab/ Northeastern University
Travel 1,100 miles due south of Miami, and before you know it you will collide with the Caribbean coast of Panama. Take a look around these shores and what will you find? Not just coral reefs as you might expect, but also seagrass beds, mangrove forests, and oysters – many of the same species, in fact, that are found in Florida, but arranged a bit differently. What are these oysters, seagrasses, and mangroves up to in the tropical parts of the world?
For a brief stint this summer I worked with Dr. Andrew Altieri at the Smithsonian Tropical Research Institute in Panama, exploring ecological questions similar to those we’ve been investigating in Florida. Dr. Altieri, much like my advisor, Dr. Kimbro, is interested in the ecology of marine communities, particularly the role of foundation species and the effects of environmental stress vs. consumers/predators in determining what grows where. In the mangroves, as well as on the rocky shores of the Panamanian Pacific coast, I helped set up several experiments using the same sort of experimental techniques as we used in Florida (cages, transplantation, etc.) to answer questions about species interactions in tropical environments. I hope I have the opportunity to return to Panama in the future as part of my graduate research. Continue reading Notes From the Field: Panama, Where Oysters Grow on Trees→
David and Randall’s NSF funded oyster study looks to understand how predators control oyster eating animals such as mud crabs and crown conchs. But this dynamic isn’t exclusive to oyster reefs. They are also investigating how predators might help maintain salt marshes and seagrass beds. In their seagrass bed studies, they have focused on a system loaded with predators: Bay Mouth Bar.
Tanya RogersFSU Coastal & Marine Lab
The very first time I drove from Tallahassee to the FSU Coastal & Marine Lab I saw a black bear crossing the Crawfordville highway. No joke. This was in June of 2010, and I had just driven 5 days and 2800 miles from San Francisco to the Florida panhandle to take up my new job on the Gulf Coast. I had just finished college in Washington state, and I had never before been to the Southeast. What sort of wild place had I ended up in?
A very wild and unique one it turns out, and one I’ve come to know better working for the past few years as a research technician for Dr. David Kimbro in the fascinating coastal habitats of this region. Primarily I’ve been traipsing around oysters reefs across the state for the collaborative biogeographic oyster study (now drawing to a close), but for the past year or so I’ve also been managing our side project in the Bay Mouth Bar system, a sandbar and seagrass bed near the FSU Marine Lab. Bay Mouth Bar is a naturalist’s playground filled with surprises and an astonishing diversity of marine creatures that never ceases to amaze me. It is also a unique study system with an intriguing history out of which we can begin asking many interesting questions. This coming fall I’m excited to be starting as Dr. Kimbro’s Ph.D. student at Northeastern University, and for part of my dissertation I’ve decided to conduct some new experimental research this spring and summer out on Bay Mouth Bar.
Bay Mouth Bar is known for its especially diverse assemblage of large predatory snails, which the ecologist Robert T. Paine conducted a study of in the late 1950’s. In 2010, we began surveying the snail community on the bar, interested in what changes might have occurred in the 50 years since Paine’s time, a period during which very little research had been done in this system. I began synthesizing some of the data we’ve gathered, as well as talking to some of the long-term residents of the area. So what has changed on Bay Mouth Bar since the 1950’s? A number of things in fact:
Of the 6 most common predatory snail species, 2 are no longer present: the true tulip and the murex snail.
The number of specialist snails (like the murex, which only eats clams) has declined relative to the number of generalist snails (those that eat a variety of prey, like the banded tulip).
There has been a drastic reduction in the overall area of the bar and changes in the coverage seagrass, specifically the loss of large meadows turtle grass (Thalassia testudinum).
Surface dwelling bivalves (e.g. scallops, cockles), once enormously abundant, are now very rare.
Why is this interesting? Worldwide, we know that species diversity is declining as a result of human activities, that specialists are being increasingly replaced by generalists, and that consumer and predator species often face a disproportionate risk of local extinction. So what are the consequences of realistic losses and changes to biodiversity? Is having a diversity of predators beneficial (e.g. both horse conchs and true tulips) to an ecosystem as a whole? Do some species matter more than others? And how do the effects of predators depend on the type of habitat they’re in, given that habitats (like seagrasses) are also changing in response to the environmental changes? These are some of the questions I’m hoping to address in Bay Mouth Bar system, in which we have documented historical changes in predator diversity.
This past week, I set up an experiment featuring a menagerie of snails tethered in different assemblages across Bay Mouth Bar. Some assemblages mimic the current assemblage, whereas others mimic the assemblage found on the bar during Paine’s time. These historical assemblages include the snail species no longer found there, which I collected from other locations where they are still abundant. Some assemblages have top predators (e.g. horse conchs) whereas others do not. Some are in turtle grass, others are in shoal grass. We’ll see how, over the course of the summer, these different assemblages affect the prey community (clams, mussels, small snails) and other elements of seagrass ecosystem functioning.
Music in the piece by Donnie Drost. Theme by Lydell Rawls.
In the Grass, On the Reef is funded by a grant from the National Science Foundation.
Shopping for gifts this winter? May I suggest one of these unique Kimbro Lab inventions, available for a limited time:
Debuted by technician Evan after conveniently breaking his hand before a long stint of marine field work, this dual glove and zip tie hybrid can protect a non-removable cast from seawater and spray, while allowing for finger mobility and dexterity. Lightweight and available in an array of fashionable colors. (Not waterproof when fully submerged.)
Need to extract stone crabs from their burrows, but worried about losing a finger? Try out Evan’s latest invention for prying stubborn crustaceans from their subterranean homes. Forged of the highest quality rebar available, this tool is optimally angled for maximum crab-removal effectiveness. Highly durable, with antique rust finish and a handle for increased leverage.
These stunning olive-green pendants are artfully fashioned by Tanya from leftover quantities of our favorite marine epoxy. Monofilament chain included. Inquire about her complete line of z-spar jewelry and sculpture. Custom pieces available.
We hope you enjoyed this last little bit of fun for the year. When we come back in 2013, Randall Hughes and David Kimbro get serious about animal behavior. The consequences of oyster, crab, and conch behavior could mean life or death, or life in fear. And as research begins in the decimated oyster reefs of Apalachicola Bay, they’ll put their theories about predators to the test.
It’s a problem commonly faced by field biologists: You want to put some particular critters out in the field in various places, but how do you keep them from getting swept away or wandering off too far, and how do you ever find them again later to see how they did? Behold the tether! So long as tethers are designed not to interfere too much with the animals’ natural behavior (walking around, burrowing, etc), leashing them to a fixed object is generally a good way to relocate them (provided you study something like crabs or snails and not lions or bald eagles). The other fun benefit of tethering marine invertebrates: you can take them for walks (albeit slow ones).
I recently conducted an experiment in which I put tethered baby clams (sunray venus and quahog, about 12 mm long) out on Bay Mouth Bar to see how their growth, survivorship, and burial depth was affected by (1) their location on the bar (NE, SW, SE, NW) and (2) the type of habitat the clams were in (sand, shoal grass, turtle grass). I checked on the clams a month later: some were still alive and growing, others were dead with clues indicating their likely cause of demise – gaping shell with no damage (stress), cracked shell (eaten by crab), drill hole in shell (eaten by predatory snail). My preliminary analysis suggests that survivorship and causes of death varied between habitat types. Next I hope to do a similar sort of study with tethered snails on Bay Mouth Bar.
Art is something I’ve always loved almost as much as biology. If I hadn’t been a biology major in college, I probably would have been an art major, and it is the fusion of the two that I like in particular: the realistic artwork of plants, animals, other living creatures, and their environments. There is something I especially enjoy about drawing plants and animals, because to draw them accurately, you have to look at them with a closeness and a consideration beyond the everyday. You notice the forms and structures and beautifully intricate details you would have never seen otherwise. I find that you see the organism in a new light, with a new appreciation, understanding, and respect.
It wasn’t until a couple years ago that I discovered the field of scientific illustration – that this marriage between biology and art was in fact an entire line of work. Artwork of biological organisms is used for a variety of purposes, including field guides, identification keys, scientific papers, descriptions of new species, textbooks, educational displays, brochures, and posters. A number of people work as full or part time scientific illustrators, often for museums or publishers, or as free lancers. Beyond the fine arts, it appears there’s a market for the exact types of drawings I’ve always loved to create.
You may wonder why scientific illustrations are still important today given the ubiquity of photography. It is mainly because there are limitations to what photographs can depict clearly. With illustrations, important details can be captured and highlighted, the background and unimportant details omitted, photographic artifacts eliminated (like obscuring highlights and shadows), and the organism best positioned to convey its important features in a way that is easily interpreted. Interactions, behaviors, and assemblages can be depicted that would be difficult or impossible to capture on film. Fossil and other extinct plants and animals can be portrayed as they would look in real life. Illustrations are also very useful for schematics and diagrams, and are very commonly used to depict medical procedures.
Scientific illustration differs from other forms of art in that accuracy is imperative, but aesthetics are also of consideration. Composition is important, as is skillful use of the artistic medium and the portrayal of three-dimensional form, light, shadow, and depth. Great illustrations should look both realistic and visually appealing, capture the right amount of detail, and perform well the interpretive function for which they were created. The medium itself can range widely depending on how the illustration is to be used. Pen and ink, colored pencil, watercolor, and other traditional media are common, and digital artwork is increasingly common today.
Last summer I decided to attend the annual conference of the Guild of Natural Science Illustrators held that year in Olympia, Washington. It was a fabulous conference where I met many phenomenal scientific illustrators, all far better artists than me, and all wonderful and friendly people with a common love of both science and art. The talks, workshops, and field trips at the conference, like the interests of the attendees, were a mixture of art and biology, encompassing everything from techniques (like how to draw fish scales accurately) to interesting local natural history (like research on crows’ ability to recognize human faces). I picked up many new techniques and ideas to take back with me and try. Having previously attended college in Washington state, it was also wonderful to return to the beautiful Pacific Northwest for a week.
Ultimately, I plan to go into biology rather than illustration as my primary career, but I hope that illustration might be a fulfilling side venture. I hope you enjoy the illustrations of mine I’ve included in this post, which are all of species found in Florida.
Serendipitous 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.
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.
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.
“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.
Throughout this week, Dr. David Kimbro has been updating us about the premature dismantling of his lab’s summer experiment in preparation for Hurricane Irene. Before this turn of events, David’s lab tech, Tanya Rogers, had written this account detailing how much work went into assembling the experiment and all of its (literally) moving parts.
Tanya RogersFSU Coastal & Marine Lab
For many labs, the summer field season is a period of intensity and madness: a time for tackling far too many projects and cramming as much research as possible into a preciously short window. It’s a demanding flurry of activity occasionally bordering on chaos. The greatest challenge for technicians like myself is to maintain order in this pandemonium of science, and to carry out as much field work as efficiently as possible without going crazy.
Although the oyster project’s fieldwork has attracted most of the attention on this blog (indeed, it is where most of the action happens), our time at the lab deserves a bit of discussion as well, as much progress on the oyster project also happens behind walls. This is especially the case nowadays, in the winter, when fieldwork is kept to a minimum on account of weather and the general inactivity of animals on the reefs. What better time to catch up on processing the zillions of samples we’d collected over the past many months, but never quite had time to get to.
Labwork is a whole different beast than the energetically-demanding, volatile nature of fieldwork – I wouldn’t go so far as to call labwork boring, but it is often incredibly repetitive, time-consuming, and demanding of extreme patience. It’s certainly not as exciting, sensational, or enjoyable as fieldwork (in my opinion), but it is just as much an integral part of the science, and anyone who goes into research will probably spend much of their time sitting at a bench, repeating the same procedure twenty-thousand times in pursuit of the great dataset (that is, until you hire techs and grad students to do it for you). Yet labwork has an appeal and mystique all of its own that’s not to be overlooked.
So while David retires to his office and catches up on the uncountable tasks at hand there, I’ve holed up in the lab and plodded steadily through the several hundred samples of ours waiting patiently in the freezer. Lately, this has involved two major tasks. The first was to process the sediment organic matter (SOM) samples from our (and Jeb Byers’s) oyster reefs collected every 6 weeks since August. A total of 640 samples needed to be transferred from bags to aluminum dishes, dried for 3 hours at 105°C to evaporate any water, weighed, combusted for 3 hours at 525°C to incinerate and volatilize any organic material, and reweighed to determine the percent of the sediment composed of organic material. This analysis will allow us to compare how oysters affect the amount of organic material in the sediment across latitude. In case you ever wanted to know, 525°C (977°F) is pretty dang hot, and the smell of burning sediment that wafts down the hall during the first half hour or so in the furnace apparently smells exactly like an electrical fire.
My second task was to process samples of oysters we’d collected from our reefs during our intensive August surveys. After thawing them out, this involved measuring the total weight, wet and dry tissue weight, and various shell dimensions of 400 individual oysters. From these data we’ll be able to calculate an oyster condition index (health indicator), which we’ll be able to compare across sites. Obtaining wet and dry tissue mass required removing and weighing the meat (my oyster shucking skills increased greatly after this exercise), and reweighing it after drying for 48 hours at 70°C (this generated some quite odorous and not-all-too-appetizing looking oyster jerky). Between the sediment and oyster samples, I admit I had a monopoly of the marine lab’s drying ovens for a short while. I can say though that sticking your face in a drying oven is a great way to warm up on a cold winter’s day.
There are a variety of ways researchers try to liven up the tedious nature of labwork. Many listen to music or books on tape, or play movies in the background, or chat with labmates if others are around. Sometimes I’ll do these things, but other times I find the quiet monotony of labwork to be rather peaceful. There’s no stress or distractions or real need for thinking – just you, the calipers, the oysters, the datasheet. You kind of get in “the mode” and it can be rather, I don’t know… zen? At least for a little while. It’s a nice contrast to the intensive and unpredictable nature of science in the field.
David Kimbro’s research is funded by the National Science Foundation.
(Editor’s Note. Although David refers to Randall’s participation on this study, her role was not elaborated upon in this video. That will be a part of the next video, on David’s collaborators, as Randall is David’s Co-PI- or Primary Investigator)
It’s been said that research techs are those who do the dirty work in science. Although true in many ways, I love being where the action is, collecting the data, turning ideas into reality. That said, here is some of my perspective on what went into our October trip and what days in the field were like.
A busy field trip like our October sampling push typically takes at least as many days to prepare for as the length of the trip itself. Although the daily blog posts covered our time in action, David and I spent most of the previous couple weeks just planning for this trip so that it could run as smoothly as it did. I feel it worth mentioning the many hours I spent pouring over tide charts and editing and re-editing our complicated schedule so that we could accomplish everything as efficiently as possible, factoring in all manner of time and tidal constraints, travel time, land and sea transportation, overnight stays, and numerous other variables, plus designing it with enough flexibility that we could adjust our plans in the field at a moments notice (and indeed we did). In addition to scheduling I also had to make sure we had all the materials we needed to for our trip, that those materials were all in working order, and that they are all packaged up accordingly and conveniently in our two vehicles. The last thing you want is to be out in the field and realize you’re missing some critical piece of equipment.
Out in the field, going to retrieve our traps and nets is always the most exciting for me, since you never know what we’re going to catch, and I was interested to see how the October fish community compared with that of July. We caught a few new fish species in our traps this round, including a beautiful spotfin butterflyfish (Chaetodon ocellatus), juvenile snapper (Lutjanus sp.), and a couple tiny pufferfish (technically striped burrfish, Chilomycterus schoepfi – they were very adorable). Equally exciting was getting to use the new motor on our skiff for the first time at our sites. Although noisy and bizarre-looking, it performed admirably in shallow water, as it was designed to. At least in terms of temperature and humidity, conditions on the reefs were considerably more pleasant for us than during the summer. It was wonderful not to be wiping sweat from your face every 10 minutes. The dramatic increase in the no-see-um population at dawn and dusk was not so pleasant however, as David has duly noted. The dawn low tide at Jacksonville brought the worst swarms we’d ever encountered in the field. Incredibly irritating both physically and mentally, they made work nearly impossible, and forced me to spend the subsequent week covered in uncountable numbers of ravenously itchy welts.
When not out on the reefs, there was rarely a moment when something didn’t need to be done – whether filtering water samples, rinsing gear, or (most frequently) extracting spat. Our only breaks seemed to be for the necessities of eating, showering, sleeping, and making coffee. (For David, coffee appears to rank just below data and samples in terms of his most valued possessions in the field.) Our biggest and most time-consuming challenge was whether we could get all of the spat extracted and tiles made for our predator-exclusion experiment in the time allotted between netting and trapping. The process of isolating spat was incredibly tedious to say the least, and particularly frustrating when, after you’ve been working on a spat for several minutes, your tool slips and the spat gets crushed, or it flies across the patio, never to be seen again. You couldn’t help but feel the spat always picked the most inconvenient places to settle. It was also quite a messy process, with water and oyster bits flying everywhere and various crabs skittering across the counter. The oysters also love to slice your fingers open during the few moments when you neglect to wear gloves. Yet in spite of the tedium, we couldn’t help noticing new and interesting critters living amongst the oysters as we broke them apart. For instance, we noticed considerably more porcelain crabs (Petrolisthes sp.) and Boonea impressa (a small, white snail that parasitizes oysters) than we’d seen in previously collected oyster samples. We also found an oyster pea crab (Pinnotheres ostreum), which lives on and steals food from the gills of oysters, and a number of dark brown cylindrical mussels (Lithophaga bisulcata) that bore into the calcareous shells of oysters. It always amazes me how many different animals can be found living within the structurally complex habitat created by species like oysters.
I remember on one of the last days of our trip, I kayaked out to our St. Augustine reefs for a final service and check while David finished up the dremeling. I remember looking upon reef #5, seeing our newly deployed, spat-covered tiles and cages, our cleaned tidal data logger housing, and our newly replaced spat stick, arranged so neatly on our marked reef, and feeling delighted at our accomplishment, knowing how much effort has gone into this setup. I remembered that in my position it’s easy to get sucked into the details, but it’s equally important to remember the big picture, and how this research will contribute to our greater understanding of oyster reef ecology.
After our field trip, as we recover from battle wounds and wait for the mud to work its way out from under our fingernails, work on the oyster project continues at the lab. For me this has meant entering lots of data and starting to process our many samples. Before you know it though, it’s time to start to preparing for our next journey onto the reefs and the adventures that await.
The Kimbro, Hughes, et al. biogeographic oyster study is funded by the National Science Foundation.