Unique foraminiferal diversity trends in the North Atlantic by Maya Prabhakar

Foraminifera are very small, amoeboid ocean protists (single celled, amoeba-like organisms) which live in the upper portion of the water column. Their tests (shells) are calcareous and are left in the fossil record after they die. While alive, they can be seen in the water column, especially in the lower latitudes where the ocean temperatures support growth (fig. 1). Though they have little to do with this particular cruise, they are the focus of my research. I use planktic foram fossils to study past climate with a current focus on the Arctic. I suspect I could start an entire blog about stable isotope geochemistry, so I'll keep my explanation here brief. Essentially, foram tests are made of calcium carbonate with oxygen obtained from the seawater they inhabit; therefore, they are representative of the isotopic ratios of the seawater. On larger scales this includes land ice mass changes, but on smaller time—and geographic—scales, these environmental changes are dependent on local seasonal and annual variables which can include freshwater input from rains and rivers and changes in sea ice, as examples. To provide further context, we can take the example of land ice mass. Understanding isotopes are the variations in atomic weight which exist in nature for a singular element (¹⁸O, ¹⁷O, ¹⁶O), we can look at what happens to the oceans during an ice age. All the ice on land has to come from precipitation over time. That precipitation comes from water vapor, which comes from the ocean. Lighter isotopes require less energy to evaporate to become that water vapor, leaving the oceans with more heavy isotopes and "enriching" the oceans in ¹⁸O. Subsequently, we can think about the precipitation, now lighter (containing more ¹⁶O relative to ¹⁸O) in isotopic ratio than the ocean. If we have a lot of rain, like a monsoon, over the ocean, the surface of the ocean will be flooded with "lighter" water, causing the mixed layer to become overall lighter than it previously was. Within that environment, forams live for approximately one month and thus represent one average month of the isotopic value of the water they inhabit and, by extension, can tell us about these influences. We can then ask questions like "how has Southeast Asian monsoon intensity changed in the last 50,000 years" or "how far has sea ice migrated into the Atlantic in geologic history" to look at the fluxes of water over time (and sometimes its origin). With modern methods, we're able to reach a seasonal resolution in some studies. It's absolutely astounding!

My interest in the North Atlantic mostly relates to its influence on the Arctic and is typically restricted to the subpolar Atlantic and the Fram Strait, but the N. Atlantic is, of course, interconnected and ocean currents do not pertain to one particular latitude, so gaining a more in-depth insight into the physical oceanography of the ocean as a whole greatly adds to my understanding of its influence on my research sites. Additionally, I use CTD data often in my work and learning the methods and the limitations of the collection process is beneficial as a CTD watch-stander on this leg. I planned on independently sampling for foraminifera on board, but, unfortunately, with the pandemic slowing shipping and making plans uncertain, I was unable to obtain the necessary equipment. Instead, I am collecting water samples to create a stable isotope record and targeting depths useful in foraminiferal research. I hope it will be informative and perhaps I, or someone else, will have another opportunity to pair the data with modern foraminiferal isotopic data in the future.

Our leg, A22, provides a unique opportunity to observe changes in real time through four ecologically important water masses: the Equatorial Warm Peripheral Water (EWPW), the Southern Sargasso Central Water (SSCW), the Northern Sargasso Central Water (NSCW), and the Non-equatorial Warm Peripheral Water (NWPW). These are not physical water masses, but relatively surficial demarcations defined by Ruddiman in 1969 based on patterns of foraminiferal diversity (fig. 2). The SSCW and NSCW have exceedingly low diversity while the NWPW and EWPW have high diversity. Foraminiferal diversity relates to the general state of zooplankton and productivity at a given site as well, extending the potential scope of the paper to others on the cruise.

 Degree of diversity is measured as the number of species that constitute ≥2% of site assemblages. If a singular species constitutes half an assemblage (a randomly generated, fractional representation of the species present), it is considered dominant. The strength of that dominance is reflected in the actual percentage of that species. For example, Globigerinoides ruber makes up 45-60% of the ship's current location (25.47', -65.69'), while at my sites of study in the Arctic, Neogloboquadrina pachyderma (the typical cold dwelling foram) makes up 85-95% of site assemblages. G. ruber and N. pachyderma thus represent opposite ends of the temperature dominance scale. Typically, we expect a trend of increasing diversity from pole to equator, but the N. Atlantic doesn't follow this expected pattern. The equatorial Atlantic has many diversity minimums and maximum diversity is found around the periphery of the N. Atlantic gyre where nutrients levels are high, salinity is intermediate, and forams are moved by the currents creating lateral mixing of species. Otherwise, salinities below 30^oN are too high to support any species besides G. ruber and any waters above 30^oN are dependent on winter nutrient dumps to support productivity.

This brings us to another interesting change we'll traverse: latitude 30^oN. Though this is an artificially drawn line, it represents the change from perpetually deep thermoclines with well mixed upper ~20m to seasonally variable, shifting thermoclines in the higher latitudes with much smaller (~5-10m) mixed layers. As it is spring going into summer, I am interested in noting zooplankton activity towards the end of our leg since this is the time of year where nutrient levels should be low up north. As we near this marked latitude, we've already seen a gradual shoaling of the thermocline and decreasing underwater vision profiler (UVP) activity (suggesting decreasing zooplankton presence). UVPs allow us to get real time, in-situ photographs of a wide range of organisms in the water column, courtesy of Stephanie O'Daly. Stephanie also very generously answers all my questions and shares papers and photos with our group. Despite the inability to absolutely identify the forams we've seen in her photos, I would hazard most of them would be G. ruber.

Figure 1 : Planktic, spinose foram at station 10, 576.2m depth. Scale bar is 2mm. Photo provided by Stephanie O'Daly.

 

Figure 2: Ruddiman (1969), ecologically distinct water masses in the N. Atlantic. Red overlay indicates the course of leg A22.

 

 

Reference: Ruddiman, William. "Recent Planktonic Foraminifera: Dominance and Diversity in North Atlantic Surface Sediments." Science 294, (June 6, 1969): 1164–67.

Societal lessons from a floating research lab by Holly Olivarez

The synergy on a hydrographic cruise is an excellent analogy for community life in any circumstance. Sixty people are on the ship for the purpose of taking measurements from a "vehicle" (more on that later) that holds many instruments to measure or collect various things in the ocean (temperature, saltiness, oxygen levels, etc.). This means we all work together towards a common, agreed-upon goal.

 

People on board the ship are identified as either part of the ship crew or the science party. The ship crew know and maintain the ship, feed everyone on the ship, provide support as needed (including medical and moral support), and keep things in order. The ship crew also deploys, runs and recovers the "vehicle" I mentioned above. The work of the ship crew graciously allows the science party to focus on their duties of collecting, measuring, recording and organizing their measurements and samples. The science party also cares for the "vehicle" we are on board for. The "vehicle" I keep referring to is called a rosette (see photo). The rosette holds 36 bottles for collecting water samples, as well as many different instruments.

Moonrise photo taken by winch operator Pam Blusk.

Humans have basic needs we all can quickly name: needs of food, water, and sleep. But humans also need acknowledgement and respect, especially in the way of being respected for our skills. This is where I am so impressed by the environment of being on this floating research lab for 30 days: each person on the ship knows their purpose and responsibility. Each person knows the shared goal of our on-board community, each person understands their role in accomplishing that goal, and each person is respected for their particular skill in working towards that shared goal.

 

As an example, the winch operator and scientist handling the rosette during the same shift acknowledge and respect each other for their individual skill. The scientist respects the winch operator for their ability to carefully lower the rosette into the water and then balance the tension on the cable carrying the rosette while lowering and then bringing back up the rosette to and from the sea floor. The winch operator respects the scientist for their skill of ensuring all of the instruments are ready to go into the water, as well as keeping track of the various depths the water bottles will be tripped so as to collect sea water on the bottles' way back up to the surface on the rosette.

 

As I walk the halls of the ship every day, I can name every person I encounter for their skill. I recognize how critical their presence is in order to ensure the shared goal is met. From engineer to steward, from captain to a first-time scientist-at-sea like me, each of us is dependent on every other person on board in order to eat, remain safe, and collect the most precise measurements from the rosette that we can. Over the course of 30 days, sixty people work and live together as a community. The synergy of it all, combined with our basic needs being met here, is admirable. I am thrilled to have had the opportunity to not only learn what a floating research lab is like but also to have witnessed what I consider an ideal community setup with principles that communities across the world could benefit from.

Quarantine in St. Thomas: A tale of love by Ali Siddiqui

As the A20 was underway in the North Atlantic, simultaneously, there was a bunch of people from all over the country scrambling to get to the end point of the 1st leg, which was the St. Thomas island.

 

Just like the 1st leg, we were also asked to be in quarantine for 2 weeks, before we could board the ship. In this post, I will try and paint a picture about how all of us managed to complete our isolation.

 

Like most places that call themselves home to a population of around 50,000 people, St. Thomas has a small airport, which for some reason was situated right at the south-west corner of the island. The thrill of entering the island, was soon overshadowed by a split second of fear, when I thought that the plane was going to land in the water. Such is the makeup of the airstrip, which is located right at the edge of the island. Meanwhile, once you enter the airport, you can see people who look like they've dressed for a carnival, greet you as you enter baggage claim. Propped up on stilts, they were dancing for the incoming passengers. I remember thinking to myself whether this was a traditional welcome dance or were they just excited to see tourists coming back to the island after the longest year that anyone of us had ever managed to live through.

 

I soon realized that even though the island is a United State territory, its soul belonged to the people of the Caribbean. St. Thomas, like other island communities in its vicinity, seems to be in love with the surrounding ocean. Even as we finished our quarantine and set sail, we were able to spot a number of boats out in the open ocean, with a single occupant, bobbing and drifting away to sea. It almost felt like long lost lovers meeting each other after an eternity, only to be separated with the passing of a wave.

 

I still had to find my way to my accommodation. The only glimpses that I could capture, as I rode in a taxi towards my Airbnb, were those of hills with tropical growth, among which were scattered houses, all of whom it seemed to me, were built to capture the best possible view of the ocean. As I understood, some of them even succeeded in doing so. Since I too wanted to witness the beauty of the island, I made sure to book my Airbnb, which overlooked the ocean from the northeast part of the island. It was the least I could do, given that we had strict instructions to not even leave our apartments for a midnight stroll.

 

 

 

And so quarantine started. Armed with food and grocery supplies for two weeks, we were all hopping to finish it as soon as possible. The euphoria of staying on the island with a spectacular view, soon turned into debilitating loneliness. It was as if the only friends I could see were the birds and the bees outside my window. And they often came to visit. Just like good friends. Life in quarantine soon became a race to finish my pending research work and coursework before boarding the ship. It also revolved around taking our temperature, twice a day and logging it. However, possibly the best day of the week used to be when we were allowed to go for Covid-19 testing and could meet other members of the A22 leg, even if for a few minutes, with social distancing. As we would drive back and forth to the testing center, we would catch glimpses of the beautiful harbor with sailboats humming in the distance. 

 

Even though St. Thomas is undeniably beautiful, but to stay inside an apartment for two weeks straight without any outside interaction, made us all wish for getting off this island at the first opportunity.

 

Now, that we're all safely onboard, maybe I don't want to be unreasonable to the island. In fact, in retrospect, it is with absolute certainty that I think I would love to come back here and explore the markets of Charlotte Amalie, the golden sand of the Magens bay beach and even the mysterious Blackbeard's castle. I think I might be falling in love.

 

 

Imaging the Ocean by Stephanie O’Daly

I'm a PhD student at the University of Alaska Fairbanks and I'm sailing on the A20/A22 US Go Ship cruises. As a part of my research working under Dr. Andrew McDonnell, I'll be deploying an instrument attached to the CTD Rosette called an Underwater Vision Profiler (UVP). This instrument helps us understand carbon cycling in the global oceans, particularly the biological carbon pump. The biological carbon pump is one part of carbon cycling in the ocean where carbon dioxide in transformed into particulate organic carbon (like phytoplankton cells) through photosynthesis at the surface of the ocean. This organic carbon then can be consumed by bacteria or zooplankton or sink to deeper depths through the effects of gravity to deeper depths. Eventually nearly all the particulate organic carbon will be transformed back into carbon dioxide through respiration. However, the deeper the particulate organic carbon can sink in the ocean will result in the longer that carbon is stored away from the atmosphere. Understanding how carbon moves and is stored in the oceans is critical during this time of rapid climate change as a result of anthropogenic carbon dioxide emissions.

The UVP consists of a camera and tiny computer contained within a pressure case that can withstand pressure of up to 6000m of water. Additionally there are lights that illuminate a known volume of water. The camera takes an image every second while the CTD rosette moves down through the ocean to just above the sea floor. The tiny computer identifies where in the image there are particles and saves that information. The UVP tells us information on particle sizes and concentration for particles as small as one tenth of a millimeter up to a few centimeters in length. For larger particles, the computer saves a photo of the particle itself. When I'm back on land I'll use machine learning software to predict and validate particle type. Most particles will be detritus (or dead or dying material), some will be fecal pellets from zooplankton or tiny animals that live in the ocean. I also will be able to identify different types of zooplankton like crustaceans, sea snails, and worms. All of this information helps us better understand how the biological carbon pump functions and help us predict how those functions may change with further climate change.

It's really exciting to be partnered with the US Go Ship project as an ancillary project. It's only through recent improvements in technology that we can collect all of this information without using precious resources like water or time on cruises like the US Go Ship project. I'm looking forward to collaborating with the physicists and chemists who have been working on this project for decades as I'm working with new types of data. Additionally, the US Go Ship program is a great platform for this type of research as it is one of the few programs that samples such large swaths of the global oceans.

Day 16 by Ben Freiberger

This is the first blog post I have ever considered writing, and well outside my comfort zone, so here goes. Hi Mom.

My name is Ben Freiberger. In August of last year, I was hired on as a lab tech for Dr. Todd Martz at Scripps Institution of Oceanography. For this cruise, I am farmed out to the Oceanographic Data Facility to collect and run discrete oxygen samples. I am sailing on both legs, A20 from Woods Hole to the Virgin Islands, and the subsequent A22 back up to Woods Hole. I am enjoying my time here and feeling like I am finally getting in the swing of things. I am excited to look at the Virgin Islands from the R/V Thompson bubble, and am really hoping to get some fish on the boat sometime soon.

Last night, April 1st, we attached a mesh bag full of Styrofoam cups, a Styrofoam head, and a few Styrofoam easter eggs to the rosette. Then, they were sent on down to ~5800m. This is typically done one cast per cruise as a neat demonstration of the immense pressure at depth, and a welcome break to the monotony. Station 43 was chosen as the cups station because it is just about as deep as we will get on this cruise. I myself shrunk three Maruchan Instant Lunch cups, and one decorated cup. These will be my souvenir gifts for family and friends. I hope they think it's as cool as I do! I am hoping we have the opportunity to make a few more on the trip back up north.


 

 Another souvenir we got is a vial of salt. The folks in the galley asked for the extra water from the deepest bottles on the station 14 cast and boiled it down to salt crystals. This salt was then split into vials for scientists and crew to take as a memento. What a wonderful gift! I went ahead and took a taste of the stuff, and it is salty alright. I am hoping we will get a second vial on the trip back up north.

 

Finally, I would like to sincerely thank the crew of the R/V Thomas G Thompson for all their hard work. The folks in the galley, the deck department, the marine technicians, and the engine department work tirelessly to make sure things are going smoothly for the scientists and everyone else on board. The vast majority of this work goes on behind the scenes and seems, from the outside, to be somewhat thankless. I think it is important for them to know that their efforts do not go unnoticed. If any of the crew of this or any other research vessel ends up reading this, thank you for all your hard work!

The Ebbs and Flows of the Atlantic by Cassondra DeFoor

Figure 1: Myself in my foul weather bib and boots standing next to the
Rosette that is equipped with 36 Niskin bottles and the CTD which are
used to collect oceanographic data.

 

This is my first time on a research cruise and thus far, I have
thoroughly enjoyed it. The first few days were spent in transit to the
first station so we were able to relax and get our sea legs. I spent
most of my time reading, watching Netflix shows that I downloaded on
my phone, and getting to know some of the science and ship crew.
During this time one of my favorite things to do was to visit the
bridge, which is where the crew operates the ship. They never turn on
any lights in the bridge even as night falls. They let their eyes
adjust to the dark night so their night vision is as keen as possible.
When they need extra light, they use a red light flash light because
it is longest in wavelength and it does not cause the eyes to readjust
much. Standing up in the bridge at night watching the ship slowly bob
with the waves is incredibly peaceful.

We are allowed to use 150 MB of WiFi data usage each day, which has
resulted in my technology habits changing drastically. Whereas I was
once addicted to the zombie scroll through social media that consumed
hours of my day, I am now filling my time in other ways. I have been
reading, playing a ton of solitaire, and solving Sudoku puzzles during
my downtime. The constant text messages, social media posts, and world
news have not been missed and I have found that some days I don't even
reach my data limit. The relaxed life on the ship has been a wonderful
and much needed recharge from normal, chaotic life. I am always so
excited when we get the chance to watch the sunset during our shifts.
It is breath taking to watch the sun change the color of the sky and
the wave crests as it sets over the horizon.

 

Figure 2: the sunset on 3/22/2021. Some of the crew and I sat on the
back deck to watch the sunset.

 

 

It's a huge plus that the food on the ship, which is served buffet
style three times a day, is so incredible. We've even be so lucky as
to have a few between meal charcuterie boards (thank you Nikki and
Liz!!). As if they weren't already going above and beyond, they boiled
seawater from one of the casts and bottles sea salt for everyone to
take home.

 

Figure 3: this was one of my favorite meals we've had so far. Pictured
is shrimp creole, Mac n cheese, and brussels sprouts. Yes, I went back
for a second serving of Mac n cheese!

 

Figure 4: The sea salt sample that I am taking home. It shows the cast
number, the depth (over 13,000 feet deep!!), and the coordinate point.

 

 

I will leave you with some things to think about if you are going on a
research cruise:

• Pack for the appropriate weather. Going on this Northern Atlantic
cruise I came prepared for cold, rough, foul weather. I did not
anticipate that by the middle of the second week, it would be T-shirt
weather and I only packed about 5 short sleeve shirts.
• Scopolamine patches are the worst of anti-nausea medications. It
gives you a horrible dry mouth and blurry vision. Instead, opt for
meclizine. It doesn't make you nearly as drowsy as Dramamine and it
lasts for 24 hours.
• Head outside to the bow or the stern in your free time as much as
you can. Maybe do an exercise outdoors. Yoga out in the sun and in the
middle of the ocean is serene.
• Bring more books and more downloaded movies than you think you'll
need. I'm already on book 4/4 and trying to make it last.
• Ask questions. I am still relatively new to this field and I've
learned so much from the people around me (not only about oceanography
but also about sailing, pirates, card games, and ships).
I am hoping these next two and a half weeks crawl by so I can soak up
as much sun as possible and enjoy this unique moment.

Life on the TGT by Francesca Alatorre

Life thus far on the R/V Thomas G. Thompson has been one of the most exciting experiences of my academic and emerging research career in oceanography. I have a large variety of experience on water-crafts, including board sports, kayaking, outrigger canoeing, and sailing small boats under 14'. But this has been the longest amount of time I have spent on a ship, especially on a ship exceeding 200'. My excitement remains as we work our way into the second week aboard. Thus far, I very fortunately have not had significant issue with motion sickness, but I will count that toward my preventive medication use on occasion. Additionally, this being my first experience on a large ship research cruise, I have also experienced my first few storms aboard the R/V Thomas G. Thompson. The first occurred during our steaming days to our first station; we waited on station for roughly 36 hours waiting for the swell and winds to calm enough for the CTD rosette to have its first cast.



Figure 1: The CTD rosette in the staging bay, after the test cast.  Figure 2: One section of the ARGO float; my contribution is the smiley face. Photo By Francesca Alatorre

 

I worked as the CTD operator for the first cast. Although, I was under extreme pressure from those above me to make sure the cast went without issues, the CTD analyst walked me through the process and answered all questions I had. Now working on the 17 cast of this cruise, I have grown the confidence I have in my new operating skills, but still will default to the knowledge of my more experienced colleagues. Consequently, the CTD rosette has run into a few rather interesting issues of the past week. Including changing out the bottle-releasing carousel when some bottles refuse to respond to the software, switching out the oxygen sensor when the data came back with too many errors, and some bottles misfiring due to insufficient tension to keep them open when needed. Despite the constant level of stress my shift partner and I feel due to being almost entirely responsible for the water samples most others will use for analysis, I still feel well supported during this wonderful adventure.

One of the activities the student watchstanders had the pleasure of doing was decorating the ARGO floats that this cruise (TN-389) will be deploying. Each float was "adopted" by various schools across the country and each float is decortated per the instructions and ideas left by the students and teachers. My contribution to one of the floats is limited to my drawing ability, pictured is my smiliey face in Figure 2. The final image I have added was taken from the stern of the ship looking toward the bow during a particularly wonderful sunrise just a few days ago. I feel this image captures my excitement to be on such an incredible adventure.

 



Figure 3: Sunrise on the R/V Thomas G. Thompson. Photo by Francesca Alatorre