As the halfway mark for our research projects approaches, this week I started trying to answer some of the questions that I outlined in my research proposal. Now that we have a better idea of the types of prey that actinotroch larvae frequently eat in the lab, we’re starting to focus in on how they actually capture and swallow their prey and hopefully we’ll see how this process changes throughout larval development. I used high speed video to record young larvae capturing algal cells and older larvae capturing ciliates to compare how the process of prey capture changes with the development of tentacles. At this point it appears that tentacles act as a sensory organ and functionally help with ingestion by trapping prey in the hood and moving it towards the mouth. However, it seems like the hood is still the star of the show throughout development. It can suck in water to create a current which draws in nearby prey it detects and manipulates prey with surprising dexterity. It can also cinch itself to a certain extent to trap prey within the hood (with the help of the tentacles) until the prey is swallowed. It's exciting to think about how much (we think) we understand about actinotroch feeding now versus just a few weeks ago and how much I’ve learned just from observing the larvae in action. To get a better idea of what’s changing in an actinotroch larval body during development, we fixed a couple hundred actinotroch larvae at different stages of development and added dyes that will bind to DNA and actin so that we can visualize cell boundaries and muscle fibers in the larvae. We haven’t taken images of the larvae yet, but hopefully when we do we’ll see how things are changing during development of tentacles in early larval stages. I was surprised this week when I found one of the actinotroch larvae beginning to settle and metamorphose into its adult form. It seems like it found a tiny bit of dead algae in the bottom of the dish that it latched onto and began to evert its metasomal sack. If this larva was in the wild, it likely would have been looking for some adequate substrate on the sea floor to settle down and build its adult body and tube to live in, but in the lab it seems like a little bit of dead algae was enough to do the trick. To give you a better idea of what’s going on, the metasomal sack looks kind of like an arm extending from the larval body now but it will eventually move all of its organs into that arm and elongate it to turn it into its adult body. Now I’m curious if the other actinotrochs are also ready to settle and are just waiting for a substrate cue that they aren’t getting in an empty glass bowl. Actinotroch development is crazy! They say you win some you lose some, and unfortunately it wasn’t all wins in lab this week. Either through a computer glitch or some mistake on my part I ended up recording over my best actinotroch predation video that I’ve been able to capture so far. So that wasn’t great. But that’s science, I guess! Nevertheless, I shall persist in my actinotroch recording endeavors. Aside from lab work, this weekend we visited the city of Coos Bay and visited some of the cool shops in town. There were a lot of vintage and thrift stores to check out, a coffee shop where I tried a sparkling espresso at Randi’s recommendation (it’s just an iced Americano with sparkling water – it was good!), and some souvenir shops with art from local artists. Afterward, we went to Seven Devils Brewery to see another local band perform. It was fun to explore the city (small as it is, it definitely feels like a city compared to Charleston). We also got to host interns and students from Oregon State University this weekend. We showed them around our labs and explored the Charleston Marine Life Center with them! It was fun to get to meet other students who are interested in marine research and get to share some of our own research with them.
Until next week :)
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This weekend our REU cohort ventured out to camp at Sunset Bay for two nights. We explored the tide pools in the morning, hiked along the cliffs during the day, made s'mores at night, and celebrated Shreyaan's 20th birthday! It was a lot of fun getting to spend time with everyone away from OIMB and to explore a new area of the coast. We made a lot of new friends in the tide pools - the gumboot chiton, sculpin, red and purple urchins, and leptasterias (a six-legged sea star) to name a few. There were also so many species of marine plants and algae that I kept bugging Riley (our REU liason and TA for the seaweed course being taught at OIMB this semester) to help me identify all of the new ones I came across. Coming from an area where our marine life is mostly subtidal, it always amazes me to have such a close look at life under the sea. The actinotroch larvae in lab have been happily gobbling up a variety of prey items we offered them this week. Our most popular menu items include the spindle-shaped, shelled ciliate Tiarina fusus and shockingly...their own siblings! Well, at least their younger conspecifics. And perhaps it's not so shocking either, as the larger actinotrochs are likely just identifying a tasty "ciliated blob" as George puts it, and likely don't actively seek out or even frequently encounter conspecifics naturally in the plankton. However, under lab conditions they take these prey frequently enough that it is very likely that zooplankton do make up an important part of their diet in larval development. Moving forward with this research project, we're planning to focus on a few key aspects of actinotroch diet and predation to help us understand the role that carnivory plays in phoronid larvae: 1. Capture - how do actinotrochs take their prey items? 2. Swallowing - how do actinotrochs ingest prey that seem to be bigger than their esophagus? 3. Digestion - how long does it take actinotrochs to digest different kinds of food? 4. Growth - how well/how quickly do larvae grow on different diets? I'm also planning to investigate how capture method changes throughout larval development and to try to determine when larvae are able to take prey as opposed to just single-celled algae. This week was a lot of chasing some pretty speedy larvae around on camera, and I think I'm finally starting to get the hang of the lab equipment and the actinotrochs' swimming behavior which makes it a little easier to capture predation events. Since this is mostly qualitative research (i.e. we're not really measuring anything here), most of my work for this project will mainly focus on recording larvae in real time and with a high-speed camera mounted to a microscope to try to capture all of the nuance that is involved in catching dinner as an actinotroch and to fill in the knowledge gap about life as a phoronid larva. That's all for now! See you next week! Hi everyone! This week the sun came out just in time for our day at Hall Lake. We took kayaks and paddle boards across the lake and climbed the giant sand dunes on the other side. After a week of getting used to the overcast weather and freezing Pacific water, no one was expecting the lake to be warm enough to swim in, so when it was, we all jumped in wearing whatever combination of clothing and bathing suits we had with us. It was great getting to see more of the natural resources that Oregon has to offer inland. As a note: it turns out the sun burns just as hot in Oregon and I got an awful sunburn on my back to prove it – I’d say it was worth it though. We also spent the Fourth of July in Coos Bay, where we got to watch fireworks over the water! One of the questions that the von Dassow lab has been looking at (and that I'll be working on this summer) is whether the large, betentacled, large-stomached, actinotroch larvae of the phoronids (a tube-building marine worm) eat more than just the single-celled algae that is currently documented in literature about their diets. In other words, whether these comparatively ferocious-looking larvae may want to eat meat in addition to their veggies. In lab this week, we took more plankton tows and filtered out just the smallest zooplankton to offer to the phoronid larvae as prey. We’ve started to see the larvae taking larger prey items and are beginning to develop a menu of items that the larvae are taking regularly. With observation and video recording, we hope to determine whether these larvae really mean to eat these plankton, and if so, how they catch and swallow them. We also went out into the field to a couple of different spots this week to collect more adult phoronids plus another tube-building worm called owenia, a variety of colorful nudibranchs, and a different genus of flatworm, notocomplana. Once they all spawn, we’ll have lots of larvae to feed and lots of larvae to feed to other larvae – it’s a larva eat larva world it seems. El and I also learned how to use the microinjector to inject tiny sea star eggs! We injected the eggs with a mix of synthetic RNA, one encoding Ect2 (a Rho activator) and the other a probe that detects active Rho. The goal is to simultaneously excite and visualize contractile movements on the egg surface during development. To give you a little behind-the-scenes view into the von Dassow lab, George uses a CRT TV as a monitor for the microinjector. A mix of old and new technology, science of the past vs. science of the future…maybe there’s something poetic here. Anyway, it was new technology for me all around. Last night (at the recommendation of George & Svetlana) a bunch of us went out to the 7 Devils Brewery in Coos Bay to see the semi-local Hot Damn Scandal band perform. They’re an awesome band! Kind of a vintage, folk-y, travelling circus, stomp-and-holler, semi-spooky vibe with a killer lead singer and a musical saw! I followed them on Spotify and bought a sticker at the show. Would recommend. That’s all for this week! See you in the next one. Hi everyone! My name is Chloe Goodsell and I'm from Richmond, Virginia. I go to William & Mary where I'm a Biology & English double major. At school, I'm a student in Dr. Jonathan Allen's marine invertebrate lab where I study the oyster flatworm, Stylochus ellipticus. I was super excited to join Dr. George von Dassow's lab this summer after reading his publications about planktonic larval carnivory as part of my own research with Dr. Allen. I'm still feeling out potential projects I might take on for the summer, but I plan to continue George's work with larval carnivory and hopefully learn more about cellular biology while I’m here! This week I’ve been getting to know Charleston, OIMB and the students and faculty I’ll be working with for the summer. Research-wise, this week was about getting familiar with some of George’s many microscopes, practicing lab techniques, and meeting some of the critters I’ll be researching at OIMB. Since George’s lab studies embryology and larval biology, we looked at eggs from sand dollars, flatworms, and barnacles to observe and record embryonic development and practiced capturing feeding behaviors of developed larvae using a high-speed camera. There are lots of precise adjustments on both the microscope itself and the processing software that can make a big difference in the final image you can produce – so far, it’s all a little intimidating but hopefully with practice I’ll get more confident in my microscopy skills! We also went out into the field a couple of times to collect adult Phoronopsis harmeri (a tube-building marine worm), barnacles, and flatworms, and to sample the plankton at the marinas nearby. After lab each day, I’ve been exploring the Coos Bay area with some of the other students here. We’ve gone on lots of walks through the woods, along the beach, and into the town of Charleston. Along the way, we’ve met some local celebrities like Pat from the ceramic shop in town (who has been making pottery in Charleston for 23 years!) and even some biological celebrities like the infamous rough-skinned newt. The Oregon coast is so beautiful and completely different than Virginia’s coast. The rocky intertidal ecosystem is home to an amazing diversity of marine life which we're only just scratching the surface of. I’m constantly impressed by the giant evergreens here, and even the life on the side of the dock is so colorful and diverse that it looks beautiful too! I’m still adjusting to feeling cold in June (and jealous about the 80+ degree weather at home in Virginia), but the fog has started to grow on me. I can’t wait to see what else Coos Bay has to offer both on land and underwater and to start focusing in on my research for the summer! See you next week :) |
AuthorHello! My name is Chloe and I am from Richmond, Virginia. I am a rising senior at William & Mary studying Biology & English. This summer, I'll be working in Dr. George von Dassow's lab studying larval carnivory. I am excited to learn lots about larval biology and the coastal Oregon ecosystem at OIMB this summer! ArchivesCategories |
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