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NAAMES-III Expedition: September 13, 2017

September 15th, 2017 by Kristina Mojica

A variety of things during a day at sea
The motion woke me up this morning around 10 am. We finally have some weather after days of calm seas. First things first, I made a B-line for the coffee machine in the galley. If you’ve never had a cup of coffee on the deck of a ship during a weather system I don’t know what you’re doing with your life. A group of five of us shot the breeze for a while on the fan-tail, discussing the weather, the plan of the day etc… Someone mentioned that hurricane Jose may spin up the coast and meet us on our way back to port.
After coffee, I made my way up to the trailer park on the 02-deck. This is where we measure atmospheric trace gases, complain about poor instrument sensitivity and plot world domination of course. Tom Bell and Mike Lawler are trying to measure amines in our instrument, an exploratory venture on this cruise. Tom and I discuss some recent trends in our data and sends me off to do some processing. This I accomplish with a heavy dose of coffee and Grateful Dead (Europe 72’). Pete Gaube stopped by and mentioned he needed some help deploying his fishing nets (you thought this was a science cruise?). He drops this long skinny net down to some 1000’s of meters and brings up the most ridiculous looking creatures. It’s pretty dam entertaining. On my way to crush some left-over pizza from lunch I ran into Jim who’s an AB on board the Atlantis. Over a game of cribbage, he tells me he’s been sailing for 37 years. Jim’s a cool dude.
Back in the main lab Cyril was staring intently at a circuit board as a variety of bolts rolled around his desk in response to the ship heave. The carcass of what used to be mass flow controller box was on the floor. I remember yesterday I mentioned I wanted to switch a valve remotely using the software on the instrument computer. This was the result of that request. In my mind, it was simple; grab a valve from the spares box and plug that bad boy in…not the case.
Later in the evening some of the grad students broke out guitars, our debut album hits the shelves this November. That’s all for now, I need to work on my dissertation.
Written by Jack Porter

NAAMES-III Expedition: September 14, 2017

September 15th, 2017 by Kristina Mojica

Here we are again, sailing, sampling, studying the ocean, and overall enjoying the adventure of living on a floating island with a diverse group of people and learning from them.  Today we are working on the most northern station and ready to bring back home samples and measurements. During my second cruise and third in the NAAMES project saga, I have developed this feeling of getting familiarized to our long transect through the North Atlantic. I will expand this, last year was like driving for the first time on a new highway or being in a different country, at the beginning it’s uncertain but at the same time exciting to be in a new place. That first time I tried to be aware of different references during the trip. Different to a new highway or city, our references are not transit signs, gas stations or a grocery store; ocean scale is just a little bit bigger. Ocean references can be as big as the Gulf Stream, eddies, or even the different population of organisms living in different regions.  Paradoxically, because of the ocean’s big scale, it is hard to see them. Standing outside on the ship’s deck while sailing through our transect without any information, you will see the magnificent blue ocean four weeks straight with some subtle temperature, wind and motion changes, but without noticing the whole different ocean ”worlds” we are passing by.  Reading ocean characteristics is a huge task that needs a wide collection of tools from thermometers to satellites. With the collected information my colleagues on board can accurate map and unravel ocean complexity.

From a microbiologist perspective, the ocean can be an intricate universe.  Microbial diversity and their interactions in the different ocean “worlds” is the main focus of my research.  Analysing the correlations and links between the micro and macro scale dynamics is a challenging feature of our work, but also the most fascinating.  How can these tiny but numerous creatures influence earth and its geochemical cycles? Well, for example, some ocean microbes can harvest sun light as energy source and create their own “food”, we called them photosynthetic organisms (yes, just like the plants) and most of the ocean life and the food chain rely on these hard-working organisms.  As you can imagine, this crucial first step in the micro scale universe affects the organisms that graze them and also the organisms that eat these grazers and so on. We can trace this chain up to macro populations of organisms as fish or whales and analyse how the amplified disturbances of the microbial scale are affecting them.  As this example of micro – macro interactions, we can find many more that seem to be science fiction, but they aren’t. For example, ocean microbes can affect cloud formation and also the transformation and sinking of atmospheric carbon into the bottom of the ocean in a global scale.  In a changing planet, how microbes behave under global disturbances will dictate in great proportion the future of earth, just as they did creating an oxygen atmosphere around 2.4 billion years ago.

Meanwhile, we will keep an eye close to these organisms and looking forward for our next cruise in March 2018.

Written by Luis Bolanos

NAAMES-III Expedition: September 11, 2017

September 15th, 2017 by Kristina Mojica

When we think about the ocean the first reflex is to imagine the blue of a paradise tropical island or massive waves hitting remote cliffs on a stormy night. The most adventurous may think about submarines exploring the deep ocean and rovers sampling underwater volcanoes. There is something extremely fascinating that sits right “in the middle” of these two worlds and that is largely unexplored. The so-called mesopelagic extends between depths of 200 and 1,000 m below the ocean surface, between the daily lit epipelagic, where famous sea-life such as phytoplankton and dolphins live, and the dark bathypelagic, where no sun light penetrates. Being far from the ocean surface, where photosynthesis empowers epipelagic ecosystems, one would expect the mesopelagic to be relatively empty. Instead, sonar operators and scientists found out that the mesopelagic hosts an extremely rich ecosystem, so dense in life that layers of fish and zooplankton (planktonic animals that include small crustaceans (including krill), jelly-like organisms, arrow worms that feed mainly on phytoplankton) can foul sonars creating the illusion of a shallower bottom! Recent studies estimate that the mesopelagic is likely to host about 10^9 tons (yes, it’s 10 with other 8 zeros behind it) of fishes, without counting crustaceans, squids and other animals that inhabit the so-called deep scattering layer.

The mesopelagic is also called the “ocean twilight zone” because it is located between the epipelagic ocean, closer to the ocean surface and the deep sea, that is never reached by the light. (Credit: Wikipedia/Creative Common)

To make things even more mysterious, part of the organisms that create the deep scattering layer migrate every sunset from the deep sea to the epipelagic, where they are tought to feed on phytoplankton and are eaten by a range of ocean predators. (Some predators actually feed on them also during the day, by performing extremely deep dives in the mesopelagic). Then, when the sun rises again, they swim back to the deep ocean. This phenomenon is called diel vertical migration and is one of the largest animal migrations on Earth. Even if it involves “only” displacements of hundreds of meters, it is experienced by small (of a thumb-size and less) animals and it happens every day. I will never complain about my commute again.

Very little is known about this “world” and its interaction with the ocean epipelagic. What are mesopelagic organisms eating exactly? And how much? What do they do during the day? What triggers their migrations? How does their movement affect the cycles of different elements (especially carbon, the building blocks of life)? How are they affected by the variability in the ocean conditions at the surface? Are they distributed in the same way in different regions in the ocean? There is a lot of work to do!

During the NAAMES research voyage we are trying to learn something about the mesopelagic in the North Atlantic in different ways. Every time the ship slows down to ~ 4 knots, we put in the water our acoustic system: the echosounder. The idea is similar to the one behind a fancy fish finder, a sonar or the way bats find their dinner: our instrument sends sound towards the deep ocean and some of the signal is reflected by surfaces with different density (for example fish bladders). By measuring the time between when the sound is sent and when it is received back and the intensity of the reflected signal, we can estimate how much “stuff” is at which depth. We do that at different frequencies so that we can describe the distribution of organisms of different sizes, but unfortunately we cannot visually “see” what’s there.

An example of the output from the echosounder from NAAMES 2 (May 2016). The x-axis shows time (in particular, the time of the day) and the y-axis shows depth. Different colors refer to the intensity of the reflected signal from different depths (i.e. red and yellow mean that there is a lot of “backscatterers”/ stuff that reflects sound, white that there is very little / nothing and blue and green represent intermediate values. This plot shows the output of the echosounder for 2 days and it’s possible to see the vertical migration of some mesopelagic organisms at sunset and sunrise.

Another tool we use to explore the mesopelagic is a net. At each station, we have a look at our echosounder and we decide at which depth we will tow our net. SSSG and crew members team up with us to put our big net at the right depth and dre the winch to tow it for a time between 40 minutes and 2 hours. When the net is brought back up to the surface it is hard not to be excited: the net is coming from the mesopelagic and we could find anything in there! After taking out our “catch” and rinsing the gear (that tends to be vaguely stinky for a while), it’s time to look at what we got: according to the location and the “layer” we targeted, so far we got a good selection of shrimp-like crustaceans, jelly-like zooplankton and a good collection of mesopelagic fish.

Examples of mesopelagic fish and zooplankton from our net tow.
(1- Hatchetfish, 2- Myctophid, 3- Bristlemouth, 4- A crustacean).
Photos by Stuart Halewood

It will be definitely fun and interesting to compare the results from our net-tow from different stations, with patterns in the echosounder and with the results of the “imaging team” that are taking snapshots of zooplankton at different depths during the water sampling sessions (if you are curious you can have a look here: ).

 

Written Alice Dellapenna

NAAMES-III Expedition: September 10, 2017

September 11th, 2017 by Kristina Mojica

The response of cloud characteristics to increasing aerosol concentrations represents one of the largest uncertainties in our current understanding of climate change. We need to better understand the ability of aerosol particles to act as cloud condensation nuclei (CCN) under relevant atmospheric conditions. CCN activation is determined by particle size, composition, and water vapor supersaturation. Texas A&M University is gathering CCN data throughout the NAAMES III cruise. This data can be compared to data collected on the previous two cruises and can be compared to the CCN data collected by the C-130 aircraft. During NAAMES III the C-130 flight patterns were altered to provide better aerosol data that can be utilized by aerosol groups on the R/V Atlantis.

Texas A&M CCN Located in Aerosol Van on board the R/V Atlantis

In our current setup, there is a condensation particle counter (CPC) located before the CCN. The CPC detects and counts aerosol particles by first enlarging the particles. The particles come into contact with butanol and then expand to a size that is more easily detected. This setup allows us to see the total number of particles being counted compared to the number of particles that are able to activate as CCN. The data will provide information on the conditions when particles are more easily activated as CCN.

Written by Brianna Hendrickson

NAAMES-III Expedition: September 9, 2017

September 11th, 2017 by Kristina Mojica

The Small Stuff Matters

The most important form of life in the ocean also happens to be the smallest. Phytoplankton provide the foundation of marine food webs, regulating global climate and the transport of nutrients and carbon. Phytoplankton populations fluctuate, sometimes growing high in numbers if they receive plenty of sunlight or nutrients. Other times, phytoplankton experience mortality, mainly from hungry grazers called microzooplankton (slightly larger carnivorous plankton) or from infectious viruses. As such vital components of the marine ecosystem, it is important to understand the balance between phytoplankton growth and death.

This is where we come in – our research team, which includes oceanographers from URI and UGA, are working to measure how often phytoplankton grow or die in the North Atlantic Ocean. Ultimately, we hope to link these findings of phytoplankton dynamics to larger-scale ocean and atmospheric measurements being made on the cruise.

On the cruise, we perform 24-hour incubation experiments with seawater collected from the water column. We sample the seawater the day its collected and a day later, measuring changes in the phytoplankton community using a range of instruments on board. One such instrument, the flow cytometer, allows us to count microscopic phytoplankton cells one-by-one. The flow cytometer takes up a sample and uses a laser to shine each cell as it passes by, distinguishing them based on specific size and fluorescence properties. After running a sample, we circle the populations, add some color to easily distinguish them and count the number of cells within each population. By comparing the number of cells gained or lost in a population each day, we can directly measure their growth and mortality rates!

Flow cytometry is just one technique we are employing on this cruise, but it is already helping to advance our knowledge of phytoplankton in the North Atlantic.

The flow cytometer we have on board the ship (left) and a typical plot (right) we see after a sample run, showing the different phytoplankton populations by color.

Written by Sean Anderson

Notes from the Field