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Revisiting the Ecology of Fear

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR_chip_predators_NCE_100Since 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

Reviewing the Oyster Study in 2010


IGOR chip_ predators_NCE 150IGOR chip- biogeographic 150IGOR chip- habitat 150IGOR chip- employment 150

Dr. David Kimbro FSU Coastal & Marine Lab
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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:

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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?

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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:

Jeb cuts blue crab from shark belly

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.

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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.

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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.

Ciao,

David

David’s research is funded by the National Science Foundation.
We want to hear from you! Add your question or comment.

Way Back When On the Reef

IGOR chip- employment 150Along with David’s remembrances of his early life in marine biology, we have a video on one of David’s collaborators in this oyster study, Jeb Byers. Like all of the collaborators on the study, Jeb attended the University of North Carolina, where he overlapped with Jon Grabowski.  Alicia Brown was sent up to help Jeb’s team during the October Oyster Push, so we lent her a Flip camera to document the proceedings.  She got footage of some of the fish they caught, including the sharks that predate their reefs.

Dr. David Kimbro FSU Coastal & Marine Lab

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L to R- Tanya Rogers, Dr. Jon Grabowski, Hanna Garland, and Dr. David Kimbro. Here you have three "generations" of researchers and techs. Just as David was once Jon's lab technician, Hanna and Tanya help David today with his projects.

Burrrrr….it’s cold down here and I love it…a nice break from the no see’ums! We are gearing up to hit the road for some regular sampling (water/sediment sampling and down load instrumentation) as well as to check on the tile experiment that began 6 weeks ago. Props again to Tanya for getting us organized to go! Although, I have some anxiety about what I’ll see on the tiles because the adhesive we used to affix the oysters may not be working as planned; more on that that in the next post after we get a visual on things.

For now, I want to pick up where Randall last left off by reminiscing about how I first got into the research/oyster business and how it’s all Jon’s fault. Like Randall, I graduated from the University of North Carolina at Chapel Hill and was equally clueless about what I wanted to do in life. However, I did know that the coast was where I wanted to be.

While Randall, Jon, and many others where schlepping around tons of oyster shell in the hot North Carolinian summer, I was having a good time surfing by day and waiting tables by night.  All in all, I’d say that my summer was much more relaxing than theirs!

But after spending lots of time enjoying the coastal environment, I realized that I needed to look into this whole marine science thing. So, I began to nose around UNC’s marine lab and volunteered a little bit. By this time, Randall had taken off to teach middle school and Jon just got a prestigious offer to conduct research in Antarctica. But there was one glitch: who was going to run his oyster project in NC? He couldn’t just push the pause button on this research. Luckily, he had one last greater helper (Meg) whom he began training to be the boss. But she needed an underling. Enter me. Because they could not find a qualified research technician within three counties to hire, Jon decided to give ignorant me a shot. I was immediately told that the work was grueling and that the pay was peanuts. But I figured it had to be better than sitting indoors and watching the clock. Plus, Randall had already done the hard work by building all of those reefs; thank goodness I wasn’t on board for that madness!

Reaping the rewards from all the hard work that Randall and Jon exerted to build the oyster reefs, I got the easy work of just monitoring them and it was fun. When Jon returned from Antarctica, he saw that I hadn’t messed up anything too badly. That, coupled with my always asking him research questions made him decide to give me a little project of my own. And it is this experience that really sent me on my way into marine ecology. So, as I paddle my kayak out to the oyster reefs, think about interesting research questions, and enjoy the scenery, I often think back about the wonderful and fortuitous opportunity that Jon first gave me.

mud crab on Alligator Harbor oyster reef

Mud crab (Panopeus herbstrii)

Ok, do I have any stories? Of course. One classic story that seems to get re-told every time Jon and I get together concerns our ripping up his restored oyster reefs to see what critters lived within them. Now, Jon was really interested in mud crabs, how they affected oysters by eating them, and how larger predators affected this dynamic by eating or scaring the mud crabs. So, while I (the rookie) was working through samples, he was a bit concerned that I was missing many of the smaller crabs. Knowing about his concern as well as being a little bit grumpy about being over worked and being a little naughty, I decided to leave about 5 or so pretty large mud crabs in my sieve. I then said, “hey Jon, to make sure I’m doing this correctly, will you check over my sample to see if I missed any crabs?”. By this time, I had already processed many, many hours worth of samples. So, when Jon looked at my sieve, he immediately freaked out and thought about how many of the other samples I must of messed up. Oh, I had such a good laugh. Thirteen years later, I think this story still gets Jon’s blood pressure up.

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Years later, David heads his own team, and he and Randall are colleagues and collaborators with Dr. Grabowski.

What else…well, the winter work was so boring in North Carolina (lots of indoor time spent going through sediment samples) that I had to turn to coffee to help me make it through the late afternoon; with Meg’s persuasion (she was an addict and wanted some company). I stubbornly refused this drug all throughout college because I did not want to be an addict with smelly coffee breathe. But Meg was very persuasive and she started me out with small doses of Dunkin Donuts froofy, flavored coffees. Boy, this and some good 80’s music really helped me survive the late afternoon hours of sorting Jon’s samples in the lab. Next thing you know, I’m asking Jon for a coffee break (“hey man, can I take a quick trip to the Double D?”) every afternoon. Because Jon was a stingy boss (I say this with love), my and Meg’s new afternoon routine really annoyed Jon. But gosh, had I been open-minded about the joys of coffee back in college, I would have graduated with honors! In summary, the boringness of Jon’s project during the winter gave rise to my love of coffee (as Tanya eloquently captured in her last post), and it bugged the crap out of Jon…that and my caffeinated singing of 80’s songs in his lab during the later winter afternoons.

I could keep going with more stories, but I don’t want to give Tanya and Hanna any ideas or ammunition, so I’ll stop here.

Talk soon,
David

David’s research is funded by the National Science Foundation.
We want to hear from you! Add your question or comment.

Yes We Did!

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- biogeographic 150The following is the first of three or so videos on the big October oyster trip.  In this one, you get a long busy day in the field condensed into two minutes (it’s much less exhausting that way).  We’ll have videos in the next couple of weeks on David’s co-collaborators (including video of the Georgia/ S. Carolina team and all the sharks they caught) and a video on David’s own team.

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The "October Oyster Push" had many objectives, but none took as much time to implement than the tile experiment. Seeing how these baby oysters- spat- grow over the next few months will give David an idea how oysters typically fare at each reef over the course of their lives.

I spent most of this past week feeling pretty darn good about having just finished our October sampling and experimental objectives out on the oyster reefs.  Of course, this glow continued into the weekend as my football team pulled out a W in Tallahassee.

But back to the science.  Although Rob chronicled each day of our crazy road trip, I want to relive it once more just to give the trip from my perspective.  So, here are my top-ten thoughts:

Number 1: Planning the details of the road trip (housing, which team is going where and when) as well as figuring out how to set up the tile experiment (see video) was pretty stressful.  Thank goodness I had Tanya around to bounce scheduling ideas off of.  Because I kept chaning my mind, I think Tanya made like 6 different versions of our schedule.

Number 2: I talked the NC and SC/GA teams into doing the aforementioned experiment with oyster spat to examine how actual predation and the fear of being eaten affects oysters up and down the coast.  I successfully convinced the teams partly because I  emphatically claimed that the additional work load would only be five hours of more work at each site.  Well, I got that wrong.  It was probably triple that estimate.  That’s one of my flaws: I always underestimate how long research tasks take, which is bad because you constantly feel behind as a result of being over-scheduling.  Rule of thumb: always multiply my work estimates by at least 2.

Number 3: I never want to see a dremel again.  With dremel in hand one evening at Saint Augustine, I had only extracted ¼ the spat I needed for the experiment but the time spent on this task had already surpassed my previous estimate.  That’s when coffee and the ability to lose yourself in the task become extremely important.  I guess I took it one oyster spat at a time.

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(L to R) Tanya, Hanna, and Cristina pick up the slack while David dremels away back at the lab space.

Number 4: I could not have lost myself in the task of setting up the experiment if it hadn’t been for Tanya, Hanna and Cristina.  Knowing that they were fully trained to carry out the sampling objectives, I did not have to busy myself with those numerous tasks, such as setting gill nets and traps (and retrieving the catch), taking sediment and water samples, etc.  In fact, after finishing the sampling objectives and follow-up lab work, they would immediately begin helping me with the experiment by cleaning adult oysters and identifying spat for me to extract with the dremel.  With that help, I was able to focus solely on dremeling.

Number 5: Dremeling 1080 spat out of adult oyster shell stinks.  Did I already say that? Well, this task deserves two spots on the top-ten list.  In tact, I probably attempted to extract over 2,000 oysters because I would often slip with the dremel and accidentally kill the oyster spat that I had spent five or so minutes on.

Catfish of Alligator Harbor

Hardhead and sail catfish seem to be the dominant predator of the Florida Gulf sites. By eating mud crabs that predate oysters, these fish perform an important function on oyster reefs.

Number 6: we couldn’t have asked for better weather.  In fact, I think there were some temperature records being set.  Despite these warmer than usual temperatures, there was about ½ the diversity and number of predatory fish on our reefs.  So, going against my expectations, these Florida sites are experiencing some seasonality in the assemblage of predators.  Interestingly, all teams were catching red drum on their reefs; guess it’s their time of year.  The red drum mostly had smaller fish in their stomachs.  The SC/GA team was still catching lots of sharks.  And catfish was still the most abundant predator on our reefs.  Those slimy things are definitely major players on southern oyster reefs because they had lost of mud crabs (who eat oysters) in their guts.  Final detail about the Florida sites is that my northern locations (Alligator Harbor on Gulf and Jacksonville area on Atlantic) had more predatory fishes than did the more southern sites in Florida…. intriguing.

Number 7: We had to change plans at the end of the week and this mid-course change actually went smoothly.  This change came about because the housing space near our Jacksonville site was not conducive for setting up the tile experiment.  Luckily, Hanna and Cristina ventured up to Jacksonville to figure all of this out for me.  This “divide and conquer” strategy allowed Tanya and me to finish up the sampling and experimental objectives in Saint Augustine, while Hanna and Cristina began sampling in Jacksonville to keep us on schedule.  And rather than resting up in Jacksonville, Hanna and Cristina ripped up oyster habitat and drove it back down to Saint Augustine.  They looked pretty rough upon that later return to Jacksonville.  But after a good dinner and a few hours of sleep, their oyster delivery allowed us to work on the materials for the Jacksonville experiment in a much better laboratory setting.

Number 8: Team morale and will to finish objectives hit a low point once we reached Jacksonville.  The lodging for the first evening was haunted with cockroaches: this is Hanna’s kryptonite.  Luckily, Tanya whipped us up some good pasta to help keep our minds off of the roaches.  The next morning, cockroaches began to seem not so bad.  When we got to the boat-launch and found there to be no wind, I knew it was trouble because this site had the reputation for being particularly buggy.  So, we headed into the mouth of our creek and hit the first reef.  Not too bad… actually, no fish in the nets.  Only a few bugs and two free hands to swipe them away.  But as we ventured further into the belly of the creek/bug hell and found tons of fish in our nets, I began to worry about mutiny.  As I was exhorting the crew to extract tons of fish from the next set of nets, I realized that freeing this many fish would take twice as long because we needed to spend an equal amount of time cursing the no-see’ums and keep them out of our ears and noses; kind of hard to do with fish in your hands.  While taking fire from the no-see’ums, we then began sustaining additional injuries from other natural agents.  I suffered my first good-sized oyster cut.  Hanna got her finger nearly cut off by a large stone crab.  For the pain finale, a decent sized catfish stabbed my hand with the barb of its dorsal fin.  I don’t blame it, but daggum that hurt.  At this point, the unpleasantness was almost comical.  Note to self: buy hats with bug nets to combat no-see’ums.

Number 9: All of the pain and stress of that week is now good fodder for the lab to laugh about and bond over.  That’s one of the perks of conducting research as a team.  And that’s one of the reasons why Big Jon, Randall and I are still collaborating.

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David walks away from the tiles he and his team spent so much time putting together. He won't know how successful the experiment was until he travels back to these sites.

Number 10: Now that we have all caught up on sleep, have relived our stories, and have begun to look at the data, I now stress about whether the tile experiment will actually work.  Like most experiments I conduct, I put a lot of effort into something that has a 50% chance of not succeeding.  For example, the spat that I extracted and adhered to tiles may have been overheated by the dremel/extraction process…are they dead already?  And then, oh boy…what if the glue doesn’t hold?  That’s what really keeps me up at night.

Till next time,

David

Roctober!

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- biogeographic 150I went to graduate school in northern California. Locals along the coast of NorCal used to refer to the month of October as Roctober because it was the most beautiful time of the year.  Well, I think the Forgotten Coast should also be privy to this monthly description because things have been beautiful around here this month.  Looking at the oyster reefs, I get the sense that things are really starting to get busy in there.  But I wonder if the ecology on oyster reefs in NC is starting to slow down.  Where are predators really having a big effect? We shall soon see.

For the past week, we have been trying to figure out how to do a lot of ambitious seeing and learning on all of our reefs.  All three teams (i.e., NC, SC/GA, and FL) need to not only sample fish and invertebrate predators on reefs (for the second time and in the dark…all because of the timing of tides in the autumn), but each team also needs to simultaneously squeeze in an experiment.  Oh, I just remembered that we also need to pay attention to other things that can explain oyster patterns: oyster food in the water (phytoplankton), water temperature, tides, and sediment properties.  So, add those to our to-do list as well!

Because this will be a ton of work to do in a short amount of time, we are sending a new crew member of the Florida team (Alicia Brown) up to help out the South Carolina/GA team.  We are going to send her up with a video camera, so it will be fun to get a glimpse into their lives over the next week.

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Jon Grabowski holds up a fish for Tanya to measure. David was Jon's lab tech at UNC.

In addition, one of the leaders from North Carolina (Jon Grabowski) has been down with us in Florida for the past week to help make sure that all three teams are doing the same thing.  While he was here, we also worked with a wonderful assistant up in Georgia (Caitlin Yeager) to figure out how to manufacture our experimental products.  The first part of this experimental puzzle involved figuring out how to remove baby oysters (spat) from oyster clumps in the field and to attach them to a standardized surface (tile).  Across all of our sites, we all want to start out with oysters of roughly the same size and age; otherwise, differences in our experiments among sites could simply be due to differences in starting oyster size or density, rather than to differences in predator diversity etc.   After we get all the spat attached to our tiles, we then built (well Tanya built most of them- thanks Tanya!) structures to put around our tiles, or not…

Tile Experiment

A partially open cage (cage control) that lets predators eat the oyster spat.

Our first structure was built to exclude all predators from munching on our oysters (i.e., predator cage).  Our second structure was a modified exclosure that mimics physical characteristics of the exclosure, but still allows predators to munch oysters (cage-control).  Finally, we have naked tiles that receive no structure or cage.  At 2 sites in NC, 2 in Georgia, and 3 in Florida), we will put each of these ‘treatments’ on all of the reefs (15 tiles/estuary or 105 tiles total).

But why do this crazy experiment thing?  Well, we will come back each month and monitor the traits of oysters and their survivorship.  With these results, we will compare survivorship or oyster traits from cages to that of the naked tile (“control”) to see if excluding predators improved oyster survivorship.  But because any improvement of oyster survivorship by the cage could simply be due to the physical structure (not to predator absence) providing shade during low tide or somehow changing flow (and food delivery), we will then compare cage results to that of the cage-control; now we can tell just how important predators are.

Another cool thing about the cages is that it may exclude predators from eating oysters, but they will not prevent predators from affecting traits of the oysters through intimidation.  So, do the traits of oysters surrounded by cages in Florida (maybe more oyster consumers) differ when compared to caged oysters in NC (maybe fewer oyster consumers).   Or, perhaps it’s that FL has more oyster food this time of year than NC and that better explains trait differences in oysters, not predators.  Or, maybe larger fish predators in Florida means less oyster consumers and less influence of oyster predation in Florida compared to NC, where there may be fewer large fish predators to eat the smaller crabs that love to munch on oysters.

To pull off this extra work, my Florida team will divide and conquer over the next week and a half.  Out of a team of four, 2 people will trap and gill net while the other two folks will set up the experiment.   This will involve ½ the team moving a head of the other team members at certain points.  But we’ll all overlap at each site for at least a few hours, which will then result in interesting stories about what each team has been observing.  Because we want to share this circus show with you over the next week, we’ll post updates every day.  We hope that this gives you a feel of what it’s like to get all of this done (both the good and the bad!).

Well, I need to go stockpile some sleep.

See ya,

David

David’s research is funded by the National Science Foundation.
We want to hear from you! Add your question or comment.

Why do we eat Apalachicola oysters instead of those from Alligator Harbor?

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- gastronomy 150IGOR chip- biogeographic 150In my previous post, I described how tides could influence the oyster patterns that we are observing throughout the Atlantic and Gulf coast.  But throughout the Gulf coast, can tides explain why most of the oysters sold in restaurants come from subtidal reefs?  Are subtidal oysters healthier, happier and thus more abundant?

Well, before I attempt to address this issue, let’s first talk about the difference between subtidal and intertidal oyster reefs.  The term intertidal refers to a habitat that spends part of the day submerged by water and the other part of the day out of the water.  In contrast, the term subtidal refers to habitats that are constantly submerged by water.  Interestingly, along the NW coast of Florida, oyster reefs are subtidal from Pensacola to Apalachicola Bay.  And east of Apalachicola, oyster reefs become intertidal.

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Fouling organisms grow on hard surfaces under water.

Now back to the second question above: are subtidal oysters happier and healthier than intertidal oysters?  Research by Dr. Charles Peterson at the University of North Carolina at Chapel Hill suggests the answer is no because both reef types have different costs and benefits that keep growth and health roughly the same.  For example, subtidal reefs may get the benefits of being inundated all the time by food-rich water, but this constant submergence also has costs that include: getting covered by fouling invertebrates (i.e., animals commonly found on the bottom of boats that look like silly puddy) that compete with oyster for food and being exposed to more marine parasites and disease.  In contrast, the harsh sun baking that intertidal oysters receive during every low tide can be painful and they may also get exposed to less food, but the sun baking also cooks off the silly-puddy competitors and it also keeps the parasites away.  In the end, these different costs keep growth rates about the same between subtidal and intertidal oyster reefs.  This is why intertidal oysters from Cedar Key, Florida can be just as big and delicious as subtidal oysters from Apalachicola.

Now I’m ready to tackle the first question  from above: why do so many more oysters come from subtidal reefs in Apalachicola than from the intertidal reefs to the east and why aren’t intertidal oysters always equally as large and tasty as subtidal oysters?  After talking with an extremely knowledgeable biologist who has been studying and working with Gulf coast oysters for nearly thirty years (John Gunter), I can fairly confidently say that the answer deals with the size of the fresh water input entering an estuary and diversity.  This is because good oyster production requires a tricky balance between fresh and salty water that keeps marine predators/disease at bay and fuels phytoplankton for growth and reproduction.  So, a larger source of fresh water input creates a larger portion of an estuary suitable for oysters to achieve this delicate balance.  But the amount and timing of fresh water input, along with the weather, varies from year to year.  As a result, one set of fresh-water input and weather conditions may be good for one portion of the estuary and not so good for the other portion of the estuary.  But the next year, this situation could become reversed, maintaining a constant level of production through varying levels of fresh water input and climate.  In other words, Apalachicola has a relatively large and diverse oyster portfolio.

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Without a steady influx of freshwater, intertidal reefs have no assurance of being consistently healthy and abundant.

In contrast to the subtidal oyster reefs in Apalachicola, the size of fresh water sources that influence intertidal oyster reefs to the east are significantly smaller.  Consequently, there are only a few spots where oysters can thrive.  When conditions are just right, these intertidal reefs produce oysters just as tasty and large as the subtidal ones form Apalachicola.   But when conditions are sub-par, those intertidal oyster reefs shut down and there are no other reefs to make up for this loss in production; these estuaries have small and non-diverse oyster portfolios.

Ok, now that I waved my arms about the difference between subtidal and intertidal oyster reefs and why restaurants mostly serve subtidal oysters, I need to go get ready for our next big outing onto the oyster reefs, which should be extremely busy, but fun.

Talk soon,
David

David’s research is funded by the National Science Foundation.
We want to hear from you! Add your question or comment below.

Searching for alternative explanations

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- biogeographic 150In many of our previous posts, we focused on how predator patterns may dictate why oyster reefs look different from NC to Florida. While a cursory look at results thus far supports this hypothesis, we’ve yet to consider alternate explanations. And failing to consider alternatives would not be very objective or scientific. After all, our job is to collect a lot of data and perform a lot of experiments that could possibly refute our predator hypothesis. Only by surviving all of these data and tests can our hypothesis gain strength, and of course it can never be proved. Continue reading

On the Road Again

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- biogeographic 150As my assistant Tanya eloquently wrote in our last post, our July efforts produced interesting data on the predatory fish and crabs that hang around oyster reefs from North Carolina to Florida.

CK_exposed_reef

Cedar Key reefs, like the one above, tended to be sparser with slightly larger oysters than those in Alligator Harbor

After working on our sleep deficits, we dialed up some Willie Nelson on the iPod and were on the road again during the second week of August.  Our goal: to determine if predator patterns on oyster reefs from NC to Florida were associated with any patterns in oysters (e.g., number and size) and smaller animals that both use oyster reefs as habitat (e.g., polychaetes and crabs) and as food (e.g., crabs).

This destructive sampling involved ripping up large sections of our reefs and placing them in large bins while trying to prevent any crabs or other critters from falling out.  Because these are marine organisms, we had to work fast and quickly get them into a temperature-controlled room (50 degrees F) back at FSU’s Marine Lab.  Easy when collecting samples from nearby Alligator Harbor, but not so easy when collecting samples at our other three sites in Florida.

KImbro Team oyster reef sitesBut before dashing back to the lab, we deployed some instrumentation and took lots of sediment and water samples (more about this stuff later).  Then, the race to keep our samples fresh commenced and mostly occurred on I-95 and I-10; I’m still seeing lane dividers and road reflectors when I close my eyes at night.  After a few hours of sleep, we would drive back across the state to another site and start the process all over again.  All of this sleep deprivation and highway racing against biological clocks made me feel like I was Smokey the Bandit boot-legging some Coors Beer across state lines (maybe I’m showing my age here, but a classic movie nonetheless).

Luckily, we had some great volunteers to help process these samples back at the lab while I was out ripping up oyster reefs, because processing each sample took a long, long time.

processing

Liz and Hanna sort the reef samples.

After a week and a half of sample processing, it was really cool (or so I hear, because I was mainly on the road) to see all the animals living within the oyster reefs and how they and the reefs themselves differed from site to site.  For instance, Alligator Harbor seemed to have dense reefs of small oysters while Cedar Key had sparse reefs with slightly larger oysters; both had few mud crabs (maybe due to the abundance of big fish?).  We also noticed that animals north of Jacksonville must be on growth hormone supplements because everything is gigantic (bigger mussels, bigger crabs, and bigger oysters).  Meanwhile, the crown conch population in St. Augustine is huge and appears to be mowing down the oysters.  So, now I have new side-project: why are crown conchs an abundant nuisance for oyster reefs in St. Augustine but not at other sites?

From one week of field work, we now have about a month or so of associated lab work that will involve counting, measuring, and identifying every organism.  I’m really excited to see how all the predator, intermediate consumer, and oyster reef data correlate from estuary to estuary.

Best,

David

David’s research is funded by the National Science Foundation.
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Rehearsal is Over

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- biogeographic 150Although we’ve busied ourselves this summer by selecting research sites and practicing various aspects of our sampling program, we have still not collected any ‘real’ data concerning the objectives of our biogeographic oyster project.  Well, this post will be short because as I write this we are hectically preparing to begin said research.  Coincidentally, tropical storm Bonnie has also decided to begin her work in the Gulf at the same time!

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You can’t enjoy watching the game if you don’t know who the players are

Dr. David Kimbro FSU Coastal & Marine Lab

See David and his crew in action, and see what animals are on Alligator Harbor reefs.

IGOR chip- habitat 150The title of this blog (a sports metaphor) is how my teacher first introduced me to marine ecology. For our oyster project, this essentially means that we need to establish who is on the oyster reefs before we can begin to make connections among predators, oysters, and their water filtration services….as well as (unfortunately) the impacts of oil.

So far, we’ve identified the organisms on the bottom rung of our food web (think of it has a pyramid): oysters, clams, amphipods, and polychaetes on the bottom rung of the food web and mud crabs and snapping shrimp on the next higher rung of the food web. Our goal this week was to begin quantifying who is at the top of this food pyramid. To do this, we deployed crab traps, bait-fish pots, and gill nets onto each of our reefs during low tide. Following the ensuing flood tide, we returned the next day to count our catch and then promptly release everyone.

hardheaded catfish

the hardhead catfish was the most abundant species trapped during this survey

Although we caught a couple of interesting things (e.g., adult stone crabs, mullet, spot, as well as juvenile pinfish, pigfish and silver perch), I was surprised by the low abundance and diversity of our catch and that the most abundant species was catfish!

But after running out of fresh water to drink and profusely perspiring all the moisture out of my body while out on the reefs, it dawned on me that nature of this catch is likely an interesting seasonal pattern (again, I’m new here!): only hardy organisms that can tolerate really hot and low oxygen waters are going to be on Florida reefs right now. Once the rest of this research team begins collecting similar data from Virginia to Florida, it will be interesting to see if these low abundance-diversity patterns might last longer in some areas (e.g., Florida with longer summer) than in others (e.g., NC with shorter summer). If that’s the case, then the cascading effects of higher order predators (things at the top of our food web) down to oysters and their water filtration services may be occur more consistently during the summer in northern than in southern estuaries.

Hmmm…..good thing we are conducting a relatively long-term study and will consistently repeat this sampling in the future to rigorously detect interesting patterns like this one.

Until next time…

The Music in the video was by Jim Crozier.  As always, we welcome submissions from local musicians. WFSU’s kayak was provided by Wilderness Way.

David’s research is funded by the National Science Foundation.

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