Thursday, August 29, 2013

Life at Sea - Emily O'Connor

This past spring semester I spent 90 days on a 112ft Schooner called the S/Y Argo. 25 Shipmates and I sailed from Tortolla, BVI to Tahiti via the Panama Canal and the Galapagos. We covered 6804 nautical miles and passed through the furthest point on Earth away from land. Life on board ship was organized by watch team and much of the day was taken up by cleaning, sitting in lectures, and cooking meals. However, the tasks always seemed to be put on hold for the frequent, but always exciting, visits from dolphins swimming at the bow or whales spotted off in the distance. 
One stop we made was to the island of Dominica in the Caribbean. There we  went on an all day hike to the second largest boiling lake in the world. Our fearless guide, Pancho, walked the whole thing barefoot. He brought a carton of eggs to show us just how hot the water was, and 8 minutes later we were snacking on hard boiled eggs cooked right in the stream. We also filled our water bottle with water from a fresh spring. Dominica's mountainous landscape was described by Christopher Columbus as a crumbled up piece of parchment paper. On the hike we learned a lot about the island's history and culture. We also got to see some of the places where the second Pirates of the Caribbean movie was filmed.
We did some diving  and saw first hand how abundant the lion fish are on the Caribbean reefs. Our guide killed 8 of them on just one dive. Similarly, on Bonaire, the lion fish have become a problem. They have lion fish festivals where people can cook and taste the fish prepared in different ways in an effort to promote fishing for the fish. Along the entire caribbean lion fish have become a problem and many of the islands are trying to battle the issue. In Dominica they would  try to feed the dead lion fish to eels in an effort to create predators for this otherwise unchallenged species.
Another unique experience we had was going though the Panama Canal. The Canal is set up with 3 locks on the Atlantic side, followed by a 50 mile long lake, and 3 locks on the Pacific side. For my research project we looked at the change in salinity going through the canal. There was a drastic change going through the locks because the lake is freshwater in contrast to the saltwater oceans. The range of the pH values went from 32-34 ppt at the entrances of the canal to less than 1 ppt in the lake. Through our data we were able to confirm the idea of the canal acting as a biological barrier due to pH that could prevent species from crossing from one ocean to the other.
One stop on our trip was to the Galapagos Islands. Because of a rather unfortunate mix up with the Ecuadorian Government and our permit we only got to spend three days on Santa Cruz. However, we were able to go diving and do some land tours. We saw giant tortoises, sea lions, hammerheads, Galapagos sharks, white tip sharks, eels, an electric ray, spotted eagle rays and even two orcas. We learned that sailors would stop in the Galapagos and pick up tortoises to keep in the hold of the boat for long passages across the Pacific. Because they could go for several months without food or water, they were a source of fresh meat for the sailors on the long passage across the Pacific.
Overall this trip was unforgettable. We were lucky enough to dive and visit some of the most amazing places in the world. It was an experience of a lifetime.

Summer Diving and Cassiopea Project

Every summer, my dad and I go on a dive trip to a different location. This year it was Cozumel, Mexico. It was such a beautiful place; the water was crystal clear every day we dove. Out of all the things we saw, my favorite was all of the sea turtles. There were a bunch of Loggerheads, and a few smaller green turtles. I think we even saw eight of them on one dive. The currents can be a bit strong, so it takes a lot of fighting to stay in one place and watch them. We always have a lot of fun swimming along, pretending to be one of the fish. I particularly enjoy diving more now that I’ve learned to identify many of the species that I see, including all of the different species of parrotfish.

Over the summer, I went down to the Key Marine Lab with Dr. Childress’ Marine Ecology class. My personal project was to count the number of Cassiopea jellyfish along transects, and compare the density to factors such as salinity and nutrients in the water. As the water was so shallow, we weren’t able to snorkel above the transects, as we’d just be kicking all the jellyfish and getting stung. So instead, we canoed down the line, counting the jellyfish on either side. This was tricky, because if you went too slowly, the canoe would shift around and float off course, but too fast, and you would zoom by and be unable to count all the jellyfish. I’m not sure how accurate our count was, because there were hundreds. The whole bottom was a carpet of jellyfish in some areas. Despite the difficulties, it was a fun day of data collection.

After we counted the jellyfish, and took water samples at each site, we were left with the task of analyzing each water sample for nitrates, and using the YSI to take the salinity, pH and dissolved oxygen. All of the tests behaved as they should, with the exception of dissolved oxygen. I’m not entirely sure what the issue was, but we ended up waiting a long time on each sample, but the reading would not settle out at any reasonable number. Eventually we just surrendered, and stuck to pH and salinity. If there’s one thing I learned from this project, it’s to never expect things to go according to plan. We ended up finding that as salinity increased, so did the jellyfish density. pH, on the other hand, had a negative correlation with jellyfish density. Interestingly, we also found that the higher the salinity was, the lower the pH, which was opposite from what we expected. 

Katie's Summer 2013

I spent the beginning part of my summer studying abroad in Panama and Costa Rica. For most of the month of May, I joined 36 pre-med and pre-dental students from Clemson University to set up clinics in less fortunate parts of the countries. We assisted local doctors and dentists in providing free medical and dental care. Over the seven days of clinics, we saw hundreds of patients and learned so much about the careers we are hoping to pursue.

As part of the dental team, I was given many incredible opportunities to perform dental procedures, like routine cleanings, fillings, and tooth extractions. This was an experience that definitely solidified my decision to pursue dentistry as a career. I also enjoyed getting to experience the cultures of Panama and Costa Rica. I met so many new people from Clemson, Panama, and Costa Rica, and my experience abroad is something I will always remember.

           The rest of the summer was spent studying for the Dental Admissions Test, applying to schools, and working at a restaurant in my hometown. Though these past few months have been memorable, I am so excited to be back at Clemson for the start of a new school year and to once again be a part of the Childress Lab!

Marine Ecology Summer 2013

This summer I spent time living on Long Key, FL as a part of the inaugural Marine Ecology class of Clemson University. After a three week lecture portion of the course, covering subjects from physical oceanography to a more in depth study of the harmful algal blooms occurring in the Keys, the class headed south to experience the Keys in person. We lived in the city of Layton and worked out the Keys Marine Lab, often out on the water snorkeling a number of Florida Bay sites as well as venturing Oceanside into the warm waters of the Atlantic.

            In the lab portion of this class we learned various techniques for collecting and analyzing data. For example, we did plankton tows at a number a sites through the Florida Bay as well as Oceanside. In addition to plankton tows, we took YSI readings and collected water samples, performing tests such as pH, ammonia concentration, nitrate concentration and alkalinity in order to observe a trend in the overall water quality. In analyzing this data, we were able to form some hypotheses about the trend in water quality moving throughout various portions of the Bay into Oceanside.

            In addition to the exercises completed in Lab, we were also tasked with designing and completing an independent research project. For this portion of the lab I chose to look at the distribution of Queen Conch in relation to the distance from shore as well as the substrate composition. We sampled these variables by laying out a 25 M x 25M grid at two sites and snorkeled them, measure population density and substrate composition at 5M intervals in 25M columns. Although we found no significant data comparing the population density to the substrate composition or distance from shore, we did find a significant difference between the two sites we sampled. We found that in these sites, identical in substrate composition and distance from shore, one had a very high population density and one had a very low population density. We can most likely attribute this to the congregating behavior of Queen Conch. Because movement is limited in this species, it is beneficial for Queen Conch to congregate in order to successfully find a mate and reproduce.

            In my time in the Keys, I found one overlying theme to be true and that is the need for close monitoring of trends in the marine environment. From events such as Global Warming to an increase in boat traffic and pollution, it is our responsibility to help manage and preserve marine species and habitats in order to maintain a healthy, functioning ecosystem.

Sunday, August 4, 2013

Congratulations Scott Miller and Katherine Heldt

Scott Miller completed his Calhoun Honors College BS Thesis
Katherine Heldt completed her Biological Sciences MS Thesis

Effects of disease and ocean acidification on the den sharing behavior of juvenile Caribbean spiny lobster, Panulirus argus

Scott Donald Miller

Calhoun Honors Undergraduate Thesis
Department of Biological Sciences
Clemson University

Dr. Michael Childress
Thesis Advisor


Chemical cues play important roles throughout marine ecosystems, and different factors can alter the way that organisms detect or interpret these cues.  Diseases in populations and global water quality changes, such as ocean acidification, can greatly alter the behavior associated with information gathered from olfaction.  The Caribbean spiny lobster, Panulirus argus, is an organism that relies on chemical cues to find protective shelters and to mediate social behavior, and both disease and ocean acidification have the potential to impact its ability to rely on these cues for these behaviors.  Our study sought to see how disease would influence lobsters’ ability to compete for shelters and how ocean acidification impacts den sharing and social behavior in these lobsters.  This study comprised of three parts. 

The first portion of the study examined the interactions between diseased and healthy lobsters in a shelter-limited environment.  A healthy lobster was placed inside of the only den in an experimental aquarium, a diseased lobster was introduced, and physical interactions were observed.  This was repeated with the same lobster inside the den, but with a healthy lobster as the intruder.  We found that the presence of a diseased lobster lowered the aggression of both healthy and diseased lobsters and that in diseased trials, the healthy lobster spent more time in the den compared to the diseased individual.

In the second part of the study, the effects of ocean acidification on lobsters’ den sharing and aggressive behavior were examined.  Lobsters were housed in pairs and observed nightly for a week in both normal and lowered pH, where aggressive acts, den sharing, and olfactory sampling behaviors were measured.  Y-maze odor preference trials were run simultaneously to determine lobsters’ odor preferences.  The Y-maze trials were conducted in three rounds.  During the first round, lobsters were kept in normal pH water and the Y-maze contained normal pH water.  In the second round, home aquaria were kept the same, but the Y-maze contained lowered pH water.  For the third round, both home aquaria and the Y-maze pH were lowered.  During behavioral observations, we found lobsters to show less aggressive acts, less den sharing, less antennule flicks, and more antennule wipes after prolonged exposure to depressed pH.  Lobsters showed some evidence of altered odor preference when the Y-maze pH was reduced.

In the final portion of the study, scanning electron microscopy was used to determine if exposure to pH damages the sensory organs of the lobsters.  At the completion of the study, lobsters’ antennules were removed, fixed, and observed under SEM.  We found similar counts of setae in both groups.  There was evidence of damage in the group exposed to lower pH, but due to a small sample size, this was inconclusive.  This study provides evidence for significantly altered den sharing and social behavior in P. argus when exposed to various stressors that are projected to continue to be an issue in the future.

Individual behavioral variation of juvenile spiny lobster (Panulirus argus) denning behaviors and the role it plays in shelter competition during habitat loss

A Thesis Presented to the Graduate School of Clemson University
In Partial Fulfillment of the Requirements for the Degree Master of Science In Biological Sciences

Katherine A Heldt

Michael J. Childress, Committee Chair


Variation in juvenile spiny lobster (Panulirus argus) aggressive and gregarious behaviors may play an important role in structuring population level interactions.  Since aggressive and gregarious behaviors were not repeatable and were found to be highly correlated with size, these behaviors were found to be largely driven by a combination of behavioral plasticity and ontogeny.  Although larger individuals were found to be the most aggressive individuals, least gregarious and often occupied crevice shelters by themselves, they did not exclude smaller, less aggressive lobsters from crevice shelters.  Surprisingly, in shelter limited situations, small, less aggressive individuals were more likely to use dens and remain in dens, while large, more aggressive individuals were more likely to remain outside of dens and disperse.  In general, larger individuals are able to walk longer distances in less time and are less likely to be preyed upon while away from shelter, suggesting that vulnerability may play an important role in the decision to share dens or disperse.  Effects of prior experiences in natural shelter-rich or natural shelter-poor habitats were also found to influence denning behaviors with individuals from natural shelter-poor habitats better responding to sudden shelter loss. Therefore, prior experiences may also play an important role in denning behavior.  This thesis provides evidence for behavioral ontogeny and plasticity in juvenile spiny lobster social behavior and is an important first step in understanding the role of individual behavioral variation in den competition and behavioral mitigation of habitat loss.

Congratulations to our Creative Inquiry Graduates

Congratulations to the Childress and Ptacek lab graduations for 2013!

Scott Miller, Eric Rice, Tyler Collins, Larissa Clarke, Kelsey McClellan

With their official B.E.E.R. mugs!
(Behavioral Ecology and Evolution Research)

Focus on Creative Inquiry 2013

Poster # 85
Personality in Lobsters: Do Juvenile Spiny Lobsters Show Repeatability in Their Social and Anti-social Behaviors?
Mentor: Dr. Michael Childress, Biological Sciences
Students: Larissa Clarke, Katie Cunningham, Katherine Heldt

Caribbean spiny lobsters are attracted to conspecific odor cues which lead to den cohabitation. However, recent studies have found that den sharing is also influenced by aggression toward conspecifics. Since aggression differences among individuals are often a result of distinct behavioral phenotypes, we wanted to test if such phenotypes occur in juvenile lobsters. Our study investigates whether gregarious and/or aggressive behaviors are repeatable for juvenile lobsters. We measured aggression by observing the number of aggressive acts (antennae flicks/pushes and body pushes) exhibited for 7 nights. We measured gregariousness by observing conspecific odor preferences in y-maze choice tests. These behaviors were measured one week after capture (time 1) and again after three months in captivity (time 2). Repeatability was determined by comparing the change in behaviors from time 1 to time 2. A significant correlation between the expression of these behaviors is evidence for repeatability and potentially fixed behavioral phenotypes. This project was partially supported by the Creative Inquiry Program.

Poster # 148
Who says Intermediacy is a Bad Thing? Influences of Community Factors on Coral Diversity in the Florida Keys
Mentor: Dr. Michael Childress, Biological Sciences
Students: Kelsey McClellan, Brandt Quirk-Royal, Kylie Smith

The patch reefs of the Florida Keys contain a diversity of coral species, which provide a foundation for a community of organisms. The intermediate disturbance hypothesis is an ecological model that suggests intermediate levels of disturbance allow for high species diversity. Based on this hypothesis, we examined if coral species diversity was related to various community factors on 14 patch reefs throughout the Florida Keys National Marine Sanctuary. Survey data of the reef was used to evaluate the complexity and species composition. We found coral species diversity was unrelated to depth or topographic complexity. Coral species diversity was negatively related to macroalgal cover. Additionally, coral species diversity was highest for intermediate levels of parrotfish abundance and parrotfish species diversity. These results suggest that parrotfish may play an important role in coral ecosystems. This project was partially supported by the Creative Inquiry program.

Poster # 73
Effects of Ocean Acidification on Aggression and Den Sharing Behavior of Juvenile Caribbean Spiny Lobsters, Panulirus argus.
Mentor: Dr. Michael Childress, Biological Sciences
Students: Scott Miller, Katherine Heldt

Acidification of seawater has been shown to impair chemoreception ability in marine crustaceans, yet no work has been done on how this may affect social behavior. We examined the effects of lowered pH on aggression, cleaning, and den sharing behavior in social, juvenile Caribbean spiny lobsters, Panulirus argus. Lobsters were observed to determine the number of aggressive acts, antennule wipes (cleaning behavior), and antennule flicks (“sniffing” behavior) in normal and acidified conditions. Y-maze trials were conducted in normal and acidified environments to determine if acidification impacts lobster activity levels and attraction to conspecific odors. We found that lobsters performed fewer aggressive acts and shared dens less frequently in the acidified environment. Decreased antennule flicks and increased antennule wipes were also observed in lower pH. Our study suggests that ocean acidification impairs lobster aggression, den sharing, and cleaning behaviors, which could have wide-ranging impacts on this ecologically and commercially important species. This project was partially supported by the Creative Inquiry program.

Benthic Ecology Meeting - Savannah, GA

 Had a great time catching up with old friends such a Dr. Dan McCarthy!

Paid a visit to Paula Deen's restaurant and had a great meal.

Enjoyed seeing the sights and sounds of Savannah.

Even the strange guitar bar the Wormhole.

Everyone seemed to be relieved to have their presentations finished.  Good work team!