Just to the east of the Ross Sea lies Cape Colbeck, our next destination. Here, ecologist Dr. Gitte McDonald is hoping to find some Emperor Penguins. In the past, Gitte has had some of her Emperors come to this area to molt. But, no one knows where they go or what they do after molting, until they are seen heading back across the Ross Sea for breeding. Gitte and her team are hoping to catch and tag Emperor Penguins to shed some light on this mystery.
Whereas we were mostly in open water during our Ross Bank surveys, now the N.B. Palmer is heading into the ice. At this time of year (e.g., late summer in the Southern Hemisphere), we didn’t know what the ice conditions would look like at Cape Colbeck. Luckily, the ice cover was more than we expected – and the ice was covered with penguins!
Ice flows off Cape Colbeck. On the look out for penguins!
Spotting penguins on the bridge. Colin, one of the Marine Technicians, makes a plan for how to safely reach the penguins.
Gitte and her team off to an ice flow to tag Emperor Penguins.
One tagged Emperor and others waiting to be tagged! Photo courtesy of Sarah Peterson, ACA permit #: 2023-003.
It’s important to note that not just anyone can jump into a zodiac and get onto the ice with penguins. Well before the cruise, Gitte had to secure the necessary permits and training to handle Emperor Penguins. And, there are a lot of rules to follow to ensure both the scientists and the penguins stay safe! So, that means that we couldn’t join Gitte’s team out on the ice, but we did have some important jobs onboard!
While the penguin ecologists were out, we geologists were wrapping up sample processing and moving our samples into the cargo hold for shipping. However, we did get some chances to be penguinologists! While “penguinologist” isn’t an actual term, it’s one we’ve adopted on the Palmer. As penguinologists, we watched from the bridge to look out for groups of Emperors and to keep eyes on the zodiac in the ice. I’m definitely adding this to my CV!
After some successful penguin tagging at Cape Colbeck, we moved more east into Marie Byrd Land, towards the Saunders Coast. While at Cape Colbeck, the N.B. Palmer could either drift in open water or use dynamic positioning to stay in the same spot if there were some large icebergs nearby. Here, the ice cover was too patchy to drift so the Captain decided to “park” in the ice to save fuel.
Parked in the ice overnight.
While Gitte and her team were out with the penguins and we were not on official penguinologist duties, we had the opportunity to take out the zodiacs for a spin. Part of the adventure is actually getting INTO the zodiac (you climb into via a rope ladder hanging over the side of the ship). These trips were probably the closest we got to being “tourists” in Antarctica, but they were also training runs for some of the crew who were interested in driving the zodiac on future expeditions. While we maintained distance from the penguins, especially the ones Gitte and her group want to tag, we did get up close and personal with some cool icebergs.
Obligatory “Hey, Mom! I’m on a zodiac in Antarctica!” picture.
Our home away from home, the Palmer, with a group of Emperor Penguins.
Gitte and her team brought 33 penguin tags with them, and used all 33 of them! Once they completed tagging, they deployed net tows (much larger than our plankton nets) to figure out what the penguins were eating. In fact, they used up all their tags ahead of schedule, so we were able to squeeze in a mini multibeam survey around the Eastern Ross Sea, which is one of the most poorly mapped regions of the Ross Sea. Unfortunately, we had to cut our bonus survey short and head north to avoid storms that were forming in our transit path across the Southern Ocean back to Lyttleton, New Zealand.
After 10 days completing multibeam surveys and Super Sites along our North-South transect of Ross Bank, we switched directions to conduct our East-West transect and finish our science days.
While mapping the shallowest portion of Ross Bank, called the bank crest, we noticed a large iceberg. Normally along our transects, we notice icebergs here and there but we kept coming across the same iceberg at the same spot. As a refresher, when you see an iceberg, you are only seeing the top 10% of the actual berg that is floating above sea level. The other 90% is below the surface. When icebergs encounter a shallow region like Ross Bank, they can get stuck – or grounded. We think this berg is grounded! Since we’ve only been seeing water for a bit, it was nice to have a landmark to keep track of during our survey.
Iceberg grounded on Ross Bank. Photo courtesy of Rachel Meyne.
After finishing our initial multibeam and subottom survey, we chose coring sites. Because the Jumbo Piston Core (JPC) was still configured from our last transect, we cored all the sites where we wanted JPCs first, before conducting the remaining super site coring (e.g., multi and kasten coring). However, before we core, we conduct water sampling to ensure we aren’t sampling mud from our coring operations. The shipboard chemists had quite a sampling marathon.
Chemical Oceanographer: Samantha Schwippert
Sam is a first year Masters Student in Dr. Kanchan Maiti’s lab at Louisiana State University. Dr. Maiti is also sailing with us! As chemical oceanographers, they are interested in understanding carbon flux in the Ross Sea, especially in the coastal regions and at the ice-shelf edge. In the Ross Sea, the formation of cold bottom waters and phytoplankton blooms act together to move inorganic and organic carbon from the atmosphere and surface ocean into the deep ocean, where it is removed from exchange with the atmosphere. Together, these processes make the Southern Ocean, and especially the coastal regions of Antarctica, an important global carbon sink (30-40% of the global CO2 uptake occurs in the Southern Ocean). Why is this important? Well, studies indicate that, within the Southern Ocean, the Ross Sea region is an important sink for anthropogenic (human derived) CO2. This means that, presently and in the past, the Southern Ocean plays an important role in regulating atmospheric CO2 concentrations and Earth’s climate system.
On the Palmer, Sam samples water from Niskin bottles on the CTD rosette, McLane Pumps, and underway sampling – plus sediment from the multicores. During CTD casts, Sam tells each bottle on the rosette to close at a different depth in the water column, resulting in a suite of samples from the water column. When the rosette is recovered, she samples the water from the bottles for nutrient content, oxygen isotopes, and natural uranium series isotopes that can track sinking particles; she also filters samples for particulate organic carbon. Sam’s favorite part about life on the Palmer is meeting everyone, the penguins, being able to experience Antarctica, midrats (a term for the midnight meal on our 24 hour ship) -really everything!
Sam sampling from the CTD rosette.
Back to Ross Bank. Once water sampling was finished at a site, we deployed the JPC! Since the JPC core barrel is typically longer than the Kasten core barrels, we can collect longer sedimentary records that extend. However, we have to wait to open these cores until they’re back at the repository. We do get a look at the sediments as we cut the core into sections onboard, but we’ll have to be patient to see the rest of it!
Cutting the Jumbo Piston Core liner as it’s pushed out of the core barrel. That’s me using the pipe cutter to cut the core linter into 1.5m sections – thankfully, I didn’t drop anything in the drink!
While JPCs are usually lined with white high density PVC pipe, we got the chance to try out clear PVC tubes similar to those used in the International Ocean Discovery Program (IODP)! Here we are (above) showing Phil, the Principal Investigator on our cruise, one of the JPCs we recovered. It is not a full barrel, as you can see from the muddy water visible at the top of the tube.
After finishing all of our JPC stations, the marine technicians reconfigured the winch for our other coring objectives. While the JPCs were a nice break from sampling, we were ready to get muddy again and jumped right into multi- and Kasten coring.
Opening the last Kasten core of our cruise! We had a lot of work ahead of us. Because the previous core was still on the table, we had to finish that sampling before we could start sampling the new core.
And with that, we finished up our science days onboard the RVIB Nathaniel B. Palmer. Over our 30 science days spread across NBP23-01 and NBP23-02, we:
acquired 7,740 square kilometers of new multibeam bathymetry data
collected >30 meters of sediment core – over 1,000 lbs of sediment,
sampled >3.5 TONS of seawater,
cleaned out the Palmer’s ice cream freezer.
But, it’s not goodbye to Ross Bank for Phil and his team – they’ll be back next year to expand our initial multibeam survey and obtain more sediment cores. For now, we will head west across the Ross Sea towards Cape Colbeck, where the penguin ecologists hope to find some Emperor Penguins to tag.
We are halfway through our allotted science days on NBP23-02, the second leg of our cruise. During our McMurdo port call, we were joined by a new group of scientists: marine ecologists who study Emperor penguins! While we are collecting our geophysical and geologic data, they are surveying the wildlife we encounter as we map Ross Bank. Their science days are at the end of the cruise, before we transit back to Lyttleton, New Zealand. We still have a lot of science to do between now and then!
Before we continue our geophysical survey, we picked up two oceanographic gliders that spent the last few months measuring different ocean water properties around McMurdo. Gliders are a type of Autonomous Underwater Vehicle (AUV) that can be outfitted with different sensors to measure water column properties. When a glider is deployed, it is given a series of waypoints. The glider will change its buoyancy to move up and down through water column, collecting data that, upon surfacing, is transmitted to researchers via satellite. Once we got word that the gliders had surfaced, it was all hands-on deck trying to spot the yellow cylinder in the vast ocean. After recovering the gliders via zodiac (a small inflatable boat), we were on our way towards Ross Bank.
Two Marine Technicians and Meredith Meyer, a scientist from the Virginia Institute of Marine Science, recovered the glider from the zodiac.
Our main objective on this expedition is to complete a sea floor bathymetric survey with multibeam sonar on and around Ross Bank. In essence, we are creating a topographic map of the seafloor. We are also collecting sub-bottom data using CHIRP sonar. This technique allows us to see the uppermost layers of sediment below the seafloor. While we are on our 12-hour shifts, one of our jobs is “watchstanding”, which involves monitoring the multibeam, CHIRP, and any other underway data we are collecting. While this job is essentially watching monitors while everyone else is off taking cores or analyzing samples, the watchstander is actually seeing newly mapped areas for the first time. As a geophysicist, Dr. Phil Bart, the chief scientist on our cruise, and his students are very interested in studying the geomorphic features on Ross Bank, and to understand past glacial activity.
As I type this post, I am watching new data coming in from the multibeam echo sounder. The rainbow lines are the previously collected data and the black space has yet to be mapped! We really are in “uncharted’ territory.
In addition to multibeam surveys, we completed a series of 5 Super Stations (SS) on a North-South transect across Ross Bank. At each SS, similar to those I described earlier during NBP23-01, we deployed the CTD, McLane water pumps, a plankton net, the MultiCorer, and a Kasten Corer. Check out my previous post to read about what these instruments and devices do! Each site takes about 6-10 hours to complete – if everything works out as planned!
Another exciting part of our cruise is the Yo-Yo Camera. Much like the name suggests, the camera moves up and down just above the seafloor. A weight hanging from the camera triggers a photo when it hits the seafloor. These photos are useful for understanding the benthic community and helps us to avoid large rocks while we are coring!
One of the many Yoyo camera photos featuring the seafloor of Ross Bank. The red dots (also circled in red) are 10 cm apart, so we can determine the size of different features/organisms.
Once we completed all 5 Super Stations on our North-South transect, the marine technicians began to configure the Jumbo Piston Corer (JPC). The JPC is similar to the Kasten Core, but it can penetrate much deeper into the sediments beneath the seafloor. Unlike the Kasten Core, on this cruise, we don’t sample the JPCs onboard. We will have to wait a few months to see what we found! At the end of our transect, we started to get into quite a bit of weather, making deck work difficult. Since configuring the JPC takes some time, we got permission to take shelter right in front of Ross Ice Shelf!
Me-half a mile from the Ross Ice Shelf!
While the troughs around Ross Bank are filled with mud that is easy to core, the Bank itself is mostly capped with sands and diamicts (mixtures of sediment with grain sizes that range from clays to cobbles), which are notoriously difficult to core and recover. Large rocks, deposited as the ice retreated, are nearly impossible to core and we had to replace more than a few cutter noses (see image and caption below).
This is what happens when you core in rocky areas. This part of the gravity/piston coring device, called the cutter nose, is located at the tip of the core pipe and “cuts” though the sediment as the pipe moves through the sediment layers. The cutter nose on the bottom left is what this component is “supposed” to look like; the other 3 rammed into rocks.
Unlike the cores we took during NBP23-01 (pre-McMurdo Station), which were generally muddy soft sediments, the cores we have collected on Ross Bank are sandier – BUT filled with foraminifers (forams, for short)! If you’re new to Expedition Antarctica, or need a reminder, I’ve been on the hunt for forams to include in my dissertation since the beginning of the expedition. These microfossils are extremely useful for micropaleontological and geochemical analyses that can help us reconstruct past ocean temperatures. With the naked eye, they look like a grain of sand. But, under the microscope, forams come in all shapes and sizes. The forams I am familiar with make their shells (called “tests”) out of calcium carbonate, but I’ve encountered a new type of foram that I haven’t seen before – the agglutinated type. The word “agglutinated” contains the Latin word agglitinare which means “to glue together”. Agglutinated forams build their tests (shells) out of sand grains or even parts of other forams! In the dry lab, where we sample the cores, I have a little microscope station set up right next to a porthole – best view in the house! Since forams are zooplankton, I can use a standard binocular microscope to see them (think: the dissecting microscopes you may have used in science class. Some scientists onboard need much more powerful microscopes to see the critters they’re after.
The two types of foraminifera I’m finding: calcareous and agglutinated. Look at all of these different shapes!
Meet the Scientists
In an earlier post, I introduced you to several scientists currently sailing on the NB Palmer. However, there are many more scientists who need introductions. Let’s meet some new people:
Geologist: Matthew Danielson
Matthew is a 3rd year PhD student in Dr. Bart (the chief scientist)’s lab at Louisiana State University. His research uses geophysical and geological methods to reconstruct ice retreat in the Ross Sea. Specifically, he’s exploring the geomorphology of Ross Bank via the multibeam and CHIRP data we are currently acquiring. Most of the features that Matthew looks for were either eroded or deposited by past glacial activity and are now covered by post-glacial sediments. For example, we can resolve a feature – such as a grounding zone wedge – with multibeam, but to see the structure of the sedimentary units in and around that feature, we use CHIRP. Exploring the spatial distribution of these features is necessary context for the other data we collect, including sediment cores. Matthew’s favorite part of this expedition is seeing all the wildlife and the Ross Ice Shelf.
Matthew cleaning multibeam data. He has to go through each line and delete any errant pings, outliers, a process that ensures that we are looking at real seafloor features.
Rachel is a first year Masters student studying paleoceanography in Dr. Molly Patterson’s lab at Binghamton University. Before this expedition, I met Rachel via email, when she was an undergraduate researcher in Dr. Amy Leventer’s lab at Colgate University. It was in Dr. Leventer’s lab that Rachel learned all about diatoms – tiny photosynthetic algae that live in the surface ocean around Antarctica, and even near the sediments in shallow waters. She is keeping VERY busy onboard, taking water samples every 6 hours to characterize the living phytoplankton assemblage in our study area. She’s also sampling water from the CTD to look at phytoplankton community depth profile. These phytoplankton also are very useful environmental indicators that are preserved in the sediment records we collect. In addition to sampling water, Rachel samples each sediment core for fossilized diatoms. One type of sample she takes is called a toothpick sample, where she collects the smallest amount of mud with a toothpick. She smears the sediment on a microscope slide and can look at and identify all the diatoms in a sample! Since these critters are TINY, Rachel has to use a microscope with 100x magnification. The Palmer has an entire Microscope Room! While the science is awesome, Rachel admits that her favorite part about life onboard the Palmer is the really nice espresso machine in the Marine Project Coordinator’s office.
Rachel looking into the microscope in the Palmer’s microscope room. Around here are examples of what she sees in the microscope: living plankton from the CTD and fossilized plankton from the cores – even microplastics (probably from our fleece jackets or sweaters- oops)!
We will finish our survey of Ross Bank by completing an East-West transect with 5 more Super Stations (water + sediment sampling). Fun fact from the penguin folks: apparently a lot of their tagged penguins like to hang out around Ross Bank!