When we look up at the stars our imagination is captured by their power, great distance, and, of course, stellar size. But equally impressive in a different way are the stars that crawl along the sea bottom here in the Antarctic and around the world – sea stars!
Sea stars are marine animals that belong to the echinoderm phylum. This makes them relatives of other marine invertebrates such as feather stars, brittle stars, sea cucumbers, sea urchin, and sand dollars. Sea stars, along with their echinoderm relatives, may not resemble us very much at first glance. But they in fact sit on our side of the branch, as what would be the ancestor to both of our lineages split from the rest of the animal kingdom around the Cambrian explosion. Adult sea stars exhibit radial symmetry, meaning their appendages are arranged around a central axis, contributing to that distinctive star-like look. Their relationship to us and other animals is more easily seen by looking at their larval development. Sea star larvae develop certain early embryonic structures in the same order that we do, and exhibit bilateral symmetry, the left side mirroring the right side.
Sea stars belong to the class Asteroidea, which roughly translates to star-like. Many sea stars are commonly seen with five arms, but some species can have up to 40 arms. Sea stars can readily regenerate lost arms. In many circumstances, species can re-grow an entire body from a lost arm. In addition to their distinctive shape and varied sizes, sea stars come in a variety of colors, as you see from the photos. This Ice Inverts expedition has given us a wonderful opportunity to see their colorful diversity firsthand.
As we move across the Southern Ocean, each sample site presents its own interesting and colorful species of sea stars, many of them endemic to Antarctica. Some of them, even within the same species, vary wildly in color. “I am not sure if these are the same thing,” is quite a frequently heard comment during our sorting process. In most cases, it is not clear why these organisms have such stunning colors or how it helps them survive down here. But whether it is for camouflage, plays into a chemical defense system, or simply a byproduct of their diet, these asteroids ‘shine’ bright in the dark depths of the Antarctic.
Latitude -63 39.4 Longitude -55 11.7
Waking up shortly after the sun has set to briefly join the members of the opposite shift for a meal, it often feels surreal. Midrats, the 11:30 pm-12:30 am night meal is what I start my day to, while for others it is their last meal of the day. This often causes minor confusion as to the correct way to discuss time. While some greet each other with good mornings, simultaneously good nights can be heard. I have even heard greetings simplified to “how is?” to be inclusive of different circadian rhythms.
Once on shift my day can be simplified to a few faucets: obtaining samples, sorting samples, and processing organisms. Though this sounds straight forward, each day does bring new surprises. When sampling via trawl, for example, it is hard to know what exactly will be in the net when it comes up. The only data we can receive about what is going on when the trawl is in the water is based on how much cable is out and what sort of force is exerted on the cable. No matter how many trawls you experience coming up, there is always a nervous excitement of what the next trawl will bring. Sometimes the net comes up overly full, sometimes it comes up practically empty, sometimes it is filled with primarily large fauna, and sometimes it comes up with what appears to be just a giant ball of mud. Despite this process being a near daily occurrence, the excitement occasionally still brings out scientists from the other shift, who want to at least see what was brought to the surface, despite the need to sleep.
Once the net comes up and the fauna is emptied from the net, scientists all gather around to coo at the various amazing animals that are seen. These animals then get sorted and processed. For the much smaller fauna, microscopes are needed. When sampling, there is often mud that comes up with the animals. This mud has a treasure trove of unique organisms as well. For some people, myself included, the mud is where their target animals reside. While some scientists groan at the muddiest samples which come up, other scientists rejoice. While from the exterior, muddy samples may not look like much, under a microscope a whole other world can be seen. There is huge amounts of biodiversity from animals that spend their lives between the sand grains. Some of these animals are younger ones of a larger, full grown counterpart, like baby brittle stars (pic). Others look far different than anything that you would expect to see of larger organisms, like Terrebellids (pic) or Aplacophora (pic).
After samples are sorted and are about to be processed, the scientists work together to try to ID the animals to the best of their abilities. Everyone has slightly different knowledge of different organisms, and no one is truly an expert in all the taxa seen. Though it was much different even only a few decades ago, many scientists rely heavily on the ability to use DNA to “barcode” animals after the cruise is complete. Though sorting based purely on morphology can be useful for processing and organizing samples and data, using DNA to identify animals is the most reliable.
Sampling the deeper reaches of the ocean is costly and time consuming. In comparison to terrestrial fauna and their ecology, marine benthic organisms are relatively unknown. With new terrestrial species being described every year, it’s no wonder why new invertebrate species are often able to be described from most sampling cruises that focus on benthic invertebrates. This cruise is unlikely to be any different. There have already been a few taxa which have been questioned as being new, but all of these will have to be further analyzed in the lab along with a thorough comb through past literature to be certain.
Ph.D. student in the Kocot Lab
University of Alabama
Latitude : -63 21. 5941 Longitude : -53 24.2078
Has anyone else heard this time and time again? It is very rare that we, as scientists (or people in general for that matter) get things exactly right the first time we try something. Whether it be an experiment, such as trying to get worms to glow on a ship (more on that later), or simply tying your shoes. When it comes to running experiments, we usually just say something along the lines of well you learned one way that it doesn’t work, now you just need to find one way that it does following Thomas Edison’s famous quote, “I have not failed. I’ve just found 10,000 ways that won’t work”. This idea rings as true today as it did in the late 1800s. The scientific method is a process and requires research, several preliminary trials to test out our ideas, more research, a failed attempt (or 2), and sometimes just going back to the drawing board to redesign a whole project. These. Things. Happen. I am not saying that you can never do anything right the first time, just that it is not common. I used to think that everything needed to be perfect before I could even start an experiment, but when I was a brand new graduate student, my advisor at the time told me that I should just try what I had and see what needed to be fixed. Trial and error. It seems like a simple idea, but when you’re passionate about a subject, it can sometimes be a tough pill to swallow.
Since we have reached the ice on the RVIB Nathaniel B. Palmer, we have been collecting so many awesome invertebrates! I am still quite partial to the annelids, or segmented worms as can be seen in the photos here (look at the iridescent one :) ) and especially the ones that glow! When we were on deck going through a sample last week in the dark during wee hours of the morning, Damien said, “Candace look! I think this worm is glowing!”. Sure enough, it was! If it hadn’t been for the dark, I am not sure we ever would have seen them glow, but we did and hopefully sometime soon, I will be able to share nice photos or videos of them glowing or bioluminescent (but not yet… we are still in the trial and error stage – see red light photo of sample containers). Currently, I just like to go enjoy the bright flashes of yellow in the dark and freezing cold room on the ship that we call Big Antarctica. This room allows us to keep animals alive in an environment that they are accustomed to I have a few different methods to try to record the bioluminescence going forward, but until then I am remaining in the mindset of, “Hmm well that’s interesting… Maybe try this instead?”
Dr. Candace J. Grimes
Postdoctoral Researcher in the Halanych Lab
Latitude: 63˚ 24’ S Longitude: 53˚ 04’ W
Today, like many other days, the RVIB Nathaniel B. Palmer and the #icyinverts crew arrived on station—this time several hundred miles off the coast of James Ross Island—and collected animals from the Antarctic seafloor by trawl. While the many of us busied ourselves identifying and sorting latest exciting batch of critters, the ship’s crew prepared to deploy our CTD. The CTD (an acronym standing for “Conductivity, Temperature, Depth”) is an ingenious instrument, lowered off the side of the ship and used to measure physical properties of the water around it as it descends. In addition to measuring the properties in its name, it can be loaded with other sensors—for example, this CTD also measures chlorophyll concentration, important for knowing where plant-like phytoplankton are in the water. The CTD can even collect seawater from particular, pre-programmed depths in specially designed tubes (called Niskin bottles) that surround the sensor array. We typically deploy the CTD as a final procedure before we begin moving to a new sampling site. Even though the data the CTD collects is often very useful, both for the scientists on the ship and others back on shore, its deployment and retrieval is not usually cause for much fanfare, but yesterday’s CTD cast was a bit different…
That’s because yesterday, our CTD went down with a rather unusual payload attached to its frame. Bags and bags of Styrofoam cups! No, not for an exciting new experiment, but rather the last step in a long arts and crafts project familiar to many veterans of oceanographic cruises—CTD cups! It is a tradition on cruises like this one to decorate Styrofoam cups for friends and family back home then send them down on a particularly deep CTD cast. Yesterday’s CTD went down to a depth of 1,800 meters (or just over a mile) below the surface. At depths that great, the Styrofoam cups experience pressures hundreds of times greater than they do on the surface, causing the plastic foam to collapse on itself. The decorated cups shrink several times over in size and the designs on them become condensed—essentially like a shrinky-dink, but substituting pressure for heat! As we steamed away to our next site, we not only had new data to pore over, but numerous adorable tiny cups to admire and compare, with thoughts of sharing these mementos and the many memories of this trip with loved ones back on land rising to the surface amidst the excitement of our ongoing adventures.
Dr. James Townsend
Providence College/Marine Biological Laboratory
Latitude: -062 40.4665 Longitude: -049 58.6846
With a week of sampling under our belt, and now having seen some really cool marine invertebrates, one of the things that has been on my mind lately is just how large the critters can be! Animals living in the Arctic and Antarctic can have unusually large body sizes compared to those in warmer waters – this phenomenon is known as polar gigantism. A similar phenomenon, abyssal (deep-sea) gigantism, is when organisms are larger at depth than those closer to the surface.
There are several possible explanations for gigantism. For instance, invertebrate body sizes are limited by how much oxygen is available in the water – since more oxygen can be held in cold water, body size is able to increase. Metabolism also isn’t as fast in colder waters, so while size may ultimately be larger, the animals live longer and grow more slowly. Bigger body sizes can help guard against starvation, so it might be beneficial in that way. Both slow metabolism and resistance to starvation allows polar organisms to withstand periods without food due in low productivity waters. Another factor leading to bigger body sizes could be less predation. Not getting eaten means more time to grow! All of the above have probably been in play over the course of millions of years, evolving certain groups to get larger and larger because the benefits outweigh the risks.
In any case, we have seen a lot of big animals and I think we’ll be seeing a lot more. There are large amphipods, sea spiders, sea mice, sea stars, sponges, and leeches, to name a few! Every time our sampling equipment returns from the depths comes new excitement for what we might find. Sometimes it’s hard to resist not going out on the main deck during off-shift hours to get a first look every time we pull in a trawl or epibenthic sled – we can call this FOMO (Fear of Missing Octopuses) or FOMF (Fear of Missing Fauna).
I look forward to the next three-ish weeks of sampling and all the Icy Inverts left to see!
Collections Manager, Non-molluscan Invertebrates
North Carolina Museum of Natural History
Latitude: -63 29.121 Longitude: -52 58.645
It’s hard to truly encapsulate all the colors of an Antarctic sunset in a picture. During the early mornings when we start the night shift, members of the Icy Inverts team often take a sunrise and sunset break, about 2 and a half hours apart. I’ve never heard the phrase “pictures don’t do it justice” more times in my life, and it couldn’t be more true. Large strokes of orange reflect off absolutely still sheets of ice, illuminating both the sea and sky with the yellow hue of the frozen sunset, or is it sunrise?
As a PhD student in the Kocot lab, I’m here to assist with the collection of the many animals that live hidden not just below the surface of the Southern Ocean but also within the sediment at the bottom. After the large macrofauna have been sorted and taken inside the dry lab to be identified, the Kocot lab can be found just next door with seemingly uninteresting buckets of sediment and scraps of miscellaneous organisms. Our sediment and scraps, however, contain a vast world of animals from the suspension feeding entoprocts (a personal favorite), to the tusk shaped Scaphopoda, and the infamously cryptic Aplacophora. Members of our team look for both animals within the sediment and even animals living on other, larger animals!
My interests in the biodiversity of this hidden world are twofold, I wish to both discover new species within the ever-changing Antarctic seas but also understand how these and others are related. While the biggest sea creatures and largest bottom dwellers are important to understanding how life has evolved on Earth, so are the small, hidden, animals almost invisible to the naked eye. Some of the world’s most charismatic and noteworthy creatures are closely related to those living in the invisible world between grains of sand. The next time you are at your favorite beach or perhaps have a sample of Antarctic sediment take a closer look. As we say in the Kocot lab, sometimes you have to… sweat the small stuff.
University of Alabama
Today (18 November) marks the first Polar Pride – a celebration of the contribution of LGBTQ+ people to polar science. 18 November is the international day of LGBTQ+ people in STEM (science, technology, engineering, and math) and Polar Pride was organized by Huw Griffiths and others and has grown into an international phenomenon with polar scientists celebrating today all over the globe (see the social media hashtag #polarpride). The Icy Inverts team includes several LGBTQ individuals and we, surrounded by our amazing allies, got together for a photo on the helicopter deck to celebrate this dimension of diversity in STEM.
The Icy Inverts team has reached Antarctica and we have seen some incredibly beautiful sights. Yesterday we saw incredible mountains, icebergs, penguins and seals (photo). This morning I watched sunrise... beginning at 2:30 AM. The last six days have been *intense* with sampling. The ship operates around the clock with two research teams alternating 12-hour shifts each day. My team relies on an instrument called an epibenthic sled to collect small animals living on top of or in the top couple centimeters of sediment on the sea floor. The net comes up looking like it is full of mud, but when we wash this material through mesh sieves, it reveals the small molluscs, worms, crustaceans, and other organisms living in this habitat (photos). We spend most of our time sorting this catch under a microscope using special cooling stages with ice water pumped through them to keep or animals at the near-freezing temperatures they are used to. We can spend hours on the deck of the ship sieving mud from a sample and then many more hours sitting at the microscope (on a rocking ship that is breaking ice!) sorting specimens.
It's been really fun for me to be back in Antarctica but especially because this time I am the leader of a team rather than a student. I've gotten so much enjoyment out of watching my students see their first giant sea spider and add new phyla to their life list (the invertebrate zoologist's equivalent to a birder's species list). I'm fortunate to have a fantastic team who have bent over backwards to help ensure the success of this expedition not only for their own research interests but to help others in their research objectives as well.
Presently, we are steaming east in the Weddell Sea to sample along the continental slope for deep-water organisms. This will be a different fauna then we have seen so far (and I am very excited). After that, we hope to head south, deeper into the Weddell Sea to collect specimens for the Halanych and Mahon population genetics projects. Hopefully the sea ice cooperates.
University of Alabama
Latitude: -063 46.154 Longitude: -057 49.085
The question “what’s for dinner?” happens to be one of the least favorite question for my wife and I to answer. As we are both scientists, we would prefer to talk about the electrons that come from our food but planning out meals and getting groceries are a much less exciting. Thankfully, my research focus on this cruise is more about electrons and metabolism as it will look at what the microbial community in the sediments are having for “dinner.”
My work in Antarctica started with a collaboration between Andrew Mahon and Ken Halanych a few years ago. Together, we pushed two papers that examined the bacteria, archaea, and meiofaunal diversity of Antarctic benthic sediments from the Ross Sea all the way to the northern tip of the Antarctic Peninsula. Both studies shared a finding: the diversity within these sediment communities were heavily influenced by the quantity and quality of organic matter. The microbial community data implicated both heterotrophs and lithotrophs in these sediments. This is also currently being invested, as our group is actively analyzing metagenomic data to investigate lithotrophic metabolism. The samples from the Ross, Amundsen, and Bellingshausen Sea have a diverse array of lithotrophic metabolism as the metagenomic data contains genes that would support hydrogen, nitrogen (both ammonium and nitrite) and sulfur oxidation.
The goal for this work is to examine the detritus degrading community in sediments from the north side of the Antarctic Pennisula and the Weddell Sea. Our past work documented more organic matter at sites in the Antarctic Peninsula, with possible sources being phytoplankton. This cruise will allow us to collect new samples from areas we expect to have relatively high and low concentrations of organic matter. These will then be investigated with metagenomics and extracellular enzyme assay to determine the genetics that are driving organic matter degradation in these benthic sediments.
Dr. Deric Learman
Central Michigan University
Hey! My name is Kyle Donnelly, a recent graduate from Texas A&M. This is my first time in the Antarctic, and I am stoked to be here. It’s also my first time south of the equator. This whole experience is crazy. The Antarctic is fascinating; It’s such a strange otherworldly environment, nothing like anything I've seen before. When I woke up, I looked out the porthole and saw icebergs for miles. After weeks out at sea with nothing on the horizon, the icebergs are a very welcome change. Earlier in the day I was out on deck working when I saw a decent sized iceberg approaching with some small black dots on it, and when it floated closer I saw that it was penguins! I wish I had a camera on me. Seeing penguins made my day. People here tell me that I’m going to get bored of seeing them but I don’t believe that’s going to happen. Its crazy seeing them for real, in the wild instead of in a zoo or aquarium. At the beginning of 2020 I would not have guessed I’d be seeing wild penguins by the end of the year, but here I am! It’s been a blast.
The trip down here was full of different experiences. Sailing down here I was able to see the stars on cloudless nights, and the stars were the brightest I had ever seen them. The zodiac constellations in the sky at the time were beautiful and in full view; Capricornus the Sea-goat, Aquarius the water bearer, especially Sagittatius, the centaur hunter with his giant bow stretching across the night sky. Saturn, Jupiter and Mars were all visible as well; I was able to watch them slowly move across the night sky, seeing them in different positions each night. They say the stars at night are big and bright deep in the heart of Texas, but that doesn’t hold a candle to the beauty of the ocean sky at night.
The change in the weather has been fun; A few weeks ago I was standing out on the bow in a t-shirt and light pants, now out there I need to get all bundled up if I’m spending any long period of time out there. It really started getting cold once we entered the straits of Magellan, which was easily the most beautiful scenery I’d ever seen. Beautiful white capped mountains accompanied by glaciers and clouds; we could not have asked for a more beautiful day to sail through the Straits.
Last night we went through our first patch of sea ice, which was a much louder experience than I was expecting! It sounded like a giant white noise machine was outside the boat. I was in the galley eating when it happened the first time, and when I heard it I wasn’t quite sure what was happening, I assumed someone on the boat was moving heavy equipment across the floor. When it happened again the boat rocked a little bit; I got up and went to the porthole. Outside I saw a sea of ice chunks surrounding the boat.
Sampling is going very well, we're seeing such fascinating creatures. There is a wonderful biodiversity here in the Antarctic, I've added some photos of my favorites like a large stony coral (Flabellum) we found, along with some very orange anemones and these neat snails (Harpovoluta charcoti) that have anemones (Isocisionis alba) on their backs! We're finding more neat stuff every day!
I couldn’t be happier to be a part of the Icy Inverts expedition. This whole experience is one I’ll remember the rest of my life.
Latitude: -63 20.091 Longitude: -53 12.789
One of the most longstanding questions in biology is “why are there so many species?”. In fact, I strongly suspect most biologists are primarily motivated by this essential question once you take all the fancy words out. Charles Darwin answered this question in part with his theory of evolution but in doing so raised many more. Of particular interest to those of us currently onboard the RVIB Nathaniel B. Palmer is where are there so many species? Or, more formally, how is biodiversity distributed across space? One interesting trend in particular that has emerged is that, generally, the most species rich areas tend to be near the equator, with biodiversity dropping off as you move farther away toward the poles. This phenomenon is known as the latitudinal diversity gradient, or LDG for short. Scientists have known about the LDG for a long time, but we still don’t understand exactly what causes it. One theory is that environments are more unstable at extreme latitudes, with cycles of glaciation leading to higher rates of extinction, and therefore fewer species. Others think that the higher temperatures near the equator create faster generation times and mutation rates, resulting in higher rates of diversification, and therefore more species.
Given the LDG one might expect Antarctica to be relatively species poor, however this is far from the case. In fact, there are some groups of animals, especially among marine invertebrates, that appear to follow the opposite trend, with more species the farther away from the equator they are. ~20% of all sea spider species, for example, are found in Antarctica. One of the trickiest things about studying the LDG is that it assumes we have a complete record of global biodiversity, when in fact ~80% of species remain undiscovered. Much of this undiscovered diversity is found in places that are very hard for humans to reach, such as Antarctica and the deep sea. Indeed, species are constantly being found in these environments making them some of the most active regions in the world for the discovery of new species. Antarctica in particular also has a large percentage of endemic species, that is species that are found nowhere else in the world, due to its unique environment as well as a circumpolar current that keeps it isolated from the rest of the world’s oceans.
All these factors make Antarctica an extremely unique and interesting environment to study, especially if you are as interested in broad patterns of species diversity and evolution as I am. But before I can start the really fun work of exploring big ideas like the LDG I need to get a better idea of how many species there are in the first place. How can we say polar regions have fewer species when we have only just started looking for them? This is one of the reasons collection trips like this one is so important, discovering new samples from all across the animal tree of life will help us chip away at the ignorance surrounding one of the most enigmatic environments on the planet. As I write this, we are currently approaching our very first sampling site, a tiny strip of land off the very tip of the Antarctic peninsula. We will begin sampling around 0600 ship time, and since I am on the night shift (lucky me!) I will be on deck to start processing our first haul. After more than two months of quarantining and weeks at sea I am extremely excited to be one the privileged few that is able to perform the important work of exploring and documenting the unique organisms that inhabit one of the most extreme (by human standards at least) and rapidly changing environments on the planet.
Ph.D. student in the Halanych Lab