Tag Archives: marine ecology

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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:

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

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

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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!

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

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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.

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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!

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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.

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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!

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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?).

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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.

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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.

Looking for Limpkin

Rob Diaz de Villegas WFSU-TV

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When the video above aired on dimensions, several individuals in our community took note of a statement made by George Weymouth.  He was explaining how hydrilla, an invasive plant species overtaking rivers in our state, had led to Limpkins entirely abandoning the Wakulla River (which has its source at Wakulla Springs).  He said that herbicides used to control the plant led to a die off of apple snails, the limpkin’s main food source.

The reaction to this statement started me on a quest, with the several aforementioned individuals guiding me closer, and at times seemingly further, from an answer to what happened to the limpkins at Wakulla Springs.

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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.”

Dude, where’s my water?

Rob Diaz de Villegas WFSU-TV

IGOR chip- human appreciation 150

St. Joe Bay is really jumping in the summer. People are everywhere; scalloping, fishing, kayaking and snorkeling. The people are mostly gone in the autumn, as they head back to work and school, and the weather is a little cooler. With less people to scare them off, you see more blue crabs, stingrays, and sharks swimming closer to the shore. It’s my favorite time of year to get footage there. When winter rolls around, the only people out on the water either have to be because they’re working (like Randall and her crew), or they’re just hardcore ecowarriors. It can make for difficult paddling in the winter (though this December is much milder than last year, when we shot this footage).

Super-low tide in St. Joe Bay.

The difficulty doesn’t so much stem from the cold, though it can get cold (especially for a native Floridian who thinks Massachusetts beach water is too chilly in July). The real challenge is the wind and the tides. It makes for a surreal landscape.  It’s mostly devoid of living animals, at least on the surface, but that north wind does push some interesting seagrass bed denizens onto the marsh with the seagrass wrack.

As I noted earlier, it has been milder this year.  Hopefully that holds for our next few EcoAdventure shoots, which include trips down the Wacissa and St. Marks rivers.  And I’ve already started planning some of next year’s shoots as well, so stay tuned!

Dan and Debbie VanVleet, who we interviewed in the video, are the proprietors of Happy Ours Kayak and Canoe Outfitter.
The music in the video was by Bruce H. McCosar.