by Katrina Lohan

Sherry Reed (in pink) and Kristina Hill pick through clumps of oysters removed from the seawall at the Harbor Branch Oceanographic Institute. (Katrina Lohan)

It was my job to hold the boat against the seawall while Kristy and Sherry hammered oysters off the wall. I also kept track as they called out numbers of Ostrea sp.—we didn’t bother counting Crassostrea virginica because they were everywhere! Unfortunately for us, there were no Isognomon sp. along the wall, which we all found odd given that this habitat was so similar to the seawall we had previously sampled, where we found that species.

After about an hour of sampling, we were all wishing for the breeze! Without that breeze, the sun intensity felt more brutal and it was stiflingly hot. Once we had enough C. virginica and Ostrea sp. we drove around to a few other spots within that inlet to see if the Isognomon sp. were more localized, but no luck. I wanted another sediment sample from this site, but it was too deep along the wall, so Sherry found a spot in the mangroves that wasn’t too dense. I hopped out of the boat and took my sediment and water samples. I started looking for Isognomon sp. on the mangrove branches, but only found a handful… We had one last look on the rocks on our way out of the inlet, but no luck there either. Bummer! Well, two out of three species isn’t too bad!

by Katrina Lohan

When Kristy and I go on these sampling excursions, we generally pack in a lot of sampling and processing into a short amount of time. We work every day, including weekends, and average 11-12 hour workdays for the two-week timeframe. So you can imagine our surprise when we finished processing all of the oysters from the second sampling location and realized that we had time in this trip for a day off!

What do two marine biologists do on their day off in Florida? Go to the beach! We inquired with the local staff as to the best place to go and were told that the Florida Inlet State Park beach was preferred as they had bathrooms and showers. We took the advice and headed to the beach for a day of R&R. I realized while sitting on the beach, mesmerized by the pounding of the waves, that it doesn’t take much for me to remember why I wanted to be a marine biologist. I am still awed by the power of water, watching the waves roll into the shore, crest, then fall, pounding into the sand and churning the shell fragments, turning them into smaller and smaller bits. I still stare at the ocean with wonder, imagining the vast and curious creatures that live in a world so completely different from the one that is familiar to me. Having these moments helps me to rejuvenate, so I can get back in the lab, continue processing my samples, and, hopefully, add to the body of knowledge about the ecology and evolution of marine creatures.

by Katrina Lohan

Microscopic cysts inside a Crassostrea virginica oyster. (Katrina Lohan)

The highest prevalence and density of parasites occurred in Crassostrea virginica oysters. So far, I have seen copepods, turbellarians (probably Urostoma sp.), pea crabs, gill parasites, and cysts (probably from cestodes). I even saw what looked like a fish embryo, which was probably just brought into the gills, and an insect larva. Seeing all these critters under the microscope has made me contemplate why oysters are considered an aphrodisiac!

by Katrina Lohan

Sea wall coated with oysters at South Bridge Marina. (Kristina Hill)

Just as before, finding enough Crassostrea virginica oysters was easy, but finding the other oysters…took a lot more scraping. The Isognomon sp. at this location were fairly small and tucked into the crevices created by C. virginica, so they could be harder to spot. I took a step-wise approach, collecting the easiest species first, then making sure I had enough Isognomon sp., and only then did I move on and attempt to locate Ostrea sp., which easily took up the majority of our time. Most of the individuals in this species were dime-sized or smaller, tucked into the crevices or even in the dead shells of other oyster species, and they were covered in turf algae and mud. It took me (and the others) about an hour to find a sufficient number of these little guys at each of our respective sampling sites along the wall.

The funniest part of sampling along this wall was that there were lots of people around who did not hesitate to yell out! I am grateful to the multiple individuals who were concerned for our safety and mentioned the pilings in the water near the wall. (The water was clear enough to see them and we walked very slowly. Also, we all wore hard-bottomed water shoes and thick gloves.) We also had multiple boaters that were traveling in and out of the marina ask what we were doing, though I think some of them probably thought that we were just there to clean off the seawall!

Once all the oysters were collected, I took one water and one subtidal sediment sample and put them on ice. Then it was back to the lab to process more oysters.

by Katrina Lohan

A dolphin surfaces in Indian River Lagoon, Fla. (Kristina Hill)

I have to admit that I really, really want to see a manatee, another commonly spotted marine mammal in the lagoon. I haven’t spotted one yet, but I’m keeping my fingers crossed!

More on dolphin courtship >>

View manatee spotted in Florida mangroves >>

by Katrina Lohan

Kristy Hill uses cable ties to secure a “biofilm collector” (a.k.a. microscope slides in a container) to a cage suspended from a local dock. (Katrina Lohan)

I have been collecting water samples at all of the oyster sampling locations, but I decided that I wanted a larger diversity of habitat types. Thus, after discussing this idea with my advisors, I have decided to also sample subtidal marine sediments at the oyster sampling locations and collect biofilm samples. I will use the same genetic techniques on all the sample types to examine the diversity and distribution of marine parasites associated with the different habitats.

To collect the biofilm samples, we are using microscope slides, which were secured into a slide holder and suspended off of a local dock. The plan is to them scrape the biofilm off the microscope slides at scheduled intervals during our trip. I can’t wait to see what’s growing on them in a few days!

Read more on parasites surviving in disease reservoirs >>

by Katrina Lohan

Jack’s Island oyster reef in Indian River Lagoon, Fla. (Katrina Lohan)

On Tuesday, we headed out to our first field location. We hopped in a small boat owned by the Smithsonian and went to Jack’s Island, an oyster reef surrounded by mangrove trees. We were able to easily find Crassostrea virginica, as it is the species that makes up the reef, and then had to spend a little more time searching for Isognomon sp. at each site to get the numbers we needed. Also, it’s virtually impossible to tell which oysters are Ostrea sp. without opening the shells, so hopefully we have enough of those….

We also had a new first at this site—this is the first time that we have had a tour boat pass us while we were collecting!

Read accounts of marine biologists hunting for oyster parasites in Panama >>