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NAAMES-III Expedition: September 20, 2017

September 23rd, 2017 by Kristina Mojica

A drifter decorated in illustrations of plankton organisms

Almost a month at sea. It’s not the first time. I have been at sea several times in these years but every time is special and unique. It is unique for the research we conduct, for the people we meet, the seas we cross, and the infinite things we still learn from each other at the most odd hours of the night. Yes, night! Nights are a big thing in plankton research. Collection, sampling and setting up of the experiments need to be done all before sunrise to prevent alteration in phytoplankton florescence as response to sunlight. The lab starts getting crowed at 1.00 AM when the first biological cast goes down to collect our precious tiny planktonic friends. I run upstairs to the galley for a quick cup of coffee and, maybe, a super fast PJ. Others are already in the galley enjoying the dinner that was put aside for them by our excellent cooks. I say good morning, we look at each other, we laugh. I run downstairs to the lab, the CTD is on deck. My colleagues and I gather all our bottles and containers and go out to collect the water to start measurements and experiments. All the water manipulations are done under dim light and since we crossed the 48°N, at very low temperature (11°C) to avoid plankton a temperature shock. We freeze but at least our creatures are happy! We start the music, bottles are filling up, a dance move contagiously run thru the lab as a remedy to the cold, we all move (some more then others) and chat and discuss each other’s ideas, methods, or sleeping troubles. Time to incubate the bottles. We call the bridge: “Hi, this is Françoise, Gayantonia, Sean and I are going to the back deck incubators, I’ll call you when we are back”. We are at sea after all, the ship is moving fast, the waves are splashing the deck, the wind is blowing and you sure want someone to know that you are out there!

Photo collage of the incubation team.

We meticulously place the bottles in the incubators based on six selected light levels that plankton communities experience in the water column. We tie up the bottles, and strap down the incubators. All wet and cold we go back to the lab, the initial analysis needs to be run, no time to stop. After a couple of hours, when cold, lack of sleep and hunger start to build up, Ben shows up with a plate full of muffins or pieces of apple cake or some other delicacies the cooks decided to prepare for us “night watchers”. We all stop for 5 minutes, we enjoy our second breakfast, and if the morning is clear I go out to experience some of the most amazing sunrise I have ever witness. Then, full of beauty and new energy, I go back in to finish up, just in time for the third (and real) breakfast!

One of the many beautiful sunrises seen on board the R/V Atlantis during NAAMES III.

It only 8 AM, the day is still long ahead of us, measurements, analysis, cleaning. It’s 12 PM, I remember I signed up to help launching one of the atmospheric balloons that collect data on wind speed, humidity and temperature. I run to the second deck, the launch is perfect, the balloon rises up in the sky but wait…did we prepare the 180 tubes for chlorophyll?!?!?!?

Launching of a radiosonde, an balloon driven sensor that measures atmospheric conditions.

Written by Gayantonia Franze

NAAMES-III Expedition: September 19, 2017

September 23rd, 2017 by Kristina Mojica

Tumbling along like a tumbling tumbleweed

Ok, so the title might just have outed my love for all things Lebowski, but hopefully I will be able to make a link, irregardless of how tenuous it might be, between tumbleweeds and and the subject of this post, drifters.

First things first, we have to remind ourselves what is a drifter, and how does it differ from a float.  First, drifters float and floats sink, yes, this is correct, floats sink, drifters don’t.  Drifters, or more precisely, passive Lagrangian drifters (PLD), are the kind we deploy during NAAMES in the North Atlantic. These are basically big bobbers which are “anchored” to the surface ocean by an amalgamation of fabric (at times brightly colored in pink camouflage), metal and plastic that is called a “holy sock drogue.”  Maybe a picture will help, with the visual aid of me in the holy sock drogue.

Peter Gaube inside a drifter. The “sock” is about 10 m long and helps to anchor the drifter into the ocean surface currents.

Ok, so what do these drifters do?  Think of them as a breadcrumb trail that we drop and leave behind the boat.  We drive this big ship through the ocean and choose what might seem to be random spots to stop and sample.  The truth is these spots are not random. They are the result of the integration of lots of satellite observations, and at times, data we get from the floats (that sink), all which help us decide where we want to sample.  Once we arrive “on station”, we drop three of these drifters.  I’ll go into details as to why we drop three of them later, but for now, think of this as the breadcrumbs we drop to mark the water mass where we have sampled.  Since the ocean is always moving, the drifter moves along with the surface layer of the ocean and allow us to follow them in time in order to stay with the same “water mass” that we initially sampled.  During the NAAMES project, we also have a big airplane that samples not only the air, but also shoots a laser into the ocean to measure phytoplankton from the surface to about 50 m.  Using the drifters, the plane can sample the same water mass that we sampled with the ship a few days prior.

So why drop three of the $3,000 drifters at once you may ask?  Well, these drifters allow us to measure something that is actually really hard to measure in the ocean, that is diffusion.  Diffusion is basically how fast do things spread apart, and how does this “rate of spreading” change based on where we dropped the drifters.  Together with other members of the (Sub)mesoscale Group, we will use the rate at which these drifters spread in time to estimate how mesoscale eddies influence the diffusion of the oceans surface waters.  To do this, we get hourly updates on the positions of all the drifter and compute the evolution of the area between the three drifters over time.  All this fun stuff won’t get analyzed for some time as we need to allow enough time for all the drifters to spread apart.

Deploying drifters is fun!  The (Sub)mesoscale Group is all about having fun while doing cutting-edge science.

In addition to dumping drifters on station, Ali and I have designed a few diffusion experiments.  We deployed (fancy word for dumped) triplicate drifters: outside of eddies, on the edge of eddies, at the point in the eddy where currents are at a maximum, and at the eddy center.  This will allow us to compute how eddies influence diffusion and compare how the impact of these eddy varies between cyclones and anticyclones (i.e., the cold and warm core eddies).

But enough with all this science, we also have fun.  It’s cool to deploy drifters as it’s a neat feeling to put out an instrument that talks with a satellite every hour for the next few years!  For example, we deployed drifters in the middle of a warm core ring, which is a really big and strong eddy that is shed from the Gulf Stream (see some details about our warm core ring project here).  One of these drifter stayed in the ring for a few days making larger loops around the eddy.  In addition, superimposed on the big loops, were small little loops that are the result of what we call inertial motions.  Basically, because the Earth rotates, surface water in the ocean oscillates in little circles all day, every day.  After a few days, the drifter was spit out of the eddy and started heading clear across the Gulf Steam.  The resulting drifter track was a very pretty pattern reminiscent of a rose.

A drifter traces a rose in a warm core ring.

To wrap up, drifters drift, just as the proverbial tumbleweed, allowing us to follow a mass of water to sample with the ship and plane.  Sometimes the patterns made by the drifters are really pretty, like our rose.

Written by Peter Gaube

NAAMES-III Expedition: September 18, 2017

September 23rd, 2017 by Kristina Mojica

Cloud formation depends on several factors, and one of those is the presence of aerosols.  Marine aerosols come from a number of sources (sea salt, biogenic aerosols, continental aerosols that are carried over by wind) and differ in size and composition.  We’ve collected CCN and CPC data to determine, respectively, the concentration of particles that activate as cloud condensation nuclei at various supersaturations, and the concentration of total aerosols encountered across the RV Atlantis’s path over the course of NAAMES III.

Marine air is relatively “clean” and contains fewer particles per cubic centimeter than continental air.  The number of particles changes during certain events: for example, the North Atlantic phytoplankton bloom (the reason we’re all here) may result in an increase in aerosol production.  Wind blown in from continents can also increase aerosol concentration.  Rain, on the other hand, may decrease aerosol concentration as particles are scavenged by falling water droplets.

Preliminary results for aerosol concentration (CPC) and cloud condensation nuclei concentration (CCN, various supersaturations) for unsized data from NAAMES III.

Our preliminary results for aerosol concentration (CPC) and cloud condensation nuclei concentration (CCN, various supersaturations) are shown above for unsized data from the current NAAMES cruise.  The fraction of aerosols that activated as CCN are shown in the plot below.  This data also consists of unsized aerosols, so differences in activated fraction could be the result of particle diameter, chemical composition, or both.

Preliminary results for the aerosol activated fractions from NAAMES III.

Over the next few months, we will pair quantitative aerosol data with weather observations, aerosol composition analysis, and biological/oceanography measurements in order to determine why changes in particle concentration and activation were observed over the course of the bloom.

Written by Jessica Mirrielees

NAAMES-III Expedition: September 15, 2017

September 23rd, 2017 by Kristina Mojica

All Quiet in the Main Lab

Oceanography is a bunch of tired people filtering the ocean.

It reminds me of a Norse story I read a long time ago:

Thor was mad at someone so he went to their place to confront them. They were scared of him and his advanced musculature, so they decided to belittle him targeting his lack of smarts. They challenged him to a drinking competition. He drank and drank and drank, but could not even finish his first cup. He got sad and, humiliated, went home. It turns out that they had hooked up the Ocean to his glass. Tricky. Unknown to him, Thor had drunk several feet of ocean. Nowadays, Thor is diminished, but every day there are tired people huddled on ships around the world making small homages to this godly act.

I wonder how many inches of seawater Oceanographers have drawn off and filtered over the century-long history of the field. I wonder how much coffee was drunk to sustain the action.

Anyways. For the past couple of weeks, we woke up to quiet alarms in dark cabins. Some of us woke up at midnight, some at 5pm. The time of day became a relative thing. Sometimes you’d share dinner with someone having breakfast. So we dressed quietly to avoid waking cabin mates on other schedules. We’d walk into the brightness of fluorescent bulb-lit halls, weaving down the narrow passageways to the movement of the ocean. We’d organize our bottles in the wintery lab air, set cold to mimic sea surface temperatures. We’d milk niskins – the bottles that collect water from set depths for us to analyse – that had been thousands of vertical metres down to the depths of the ocean, a truly mind blowing thing. I often wonder what tales the niskins could tell of life and events in the deep. Chatter at the niskins changed with the mood of the cruise: mostly lively and light hearted, sometimes grumpy and tired, sometimes entirely absent as people focused on sampling and the day ahead, silent while the wind and salty air blew by.

CTD going down to collect water for filtration. Photo credit: Gayantonia Franze

Then into the lab and the loud music and the vacuum pumps and the coffee and pounding of Oreos. And the filtering. Always the filtering. You get to know a lot about a person while they are filtering for hours a day. You get to see them at their best and worst. You get to see how they solve problems while alert or groggy. You find out about their passions and drives. You find out that they like Miley Cyrus. A lot. Nothing makes a group come together like filtering.

But now the last vacuum pump has fallen silent. The last desperate nap has been had. No more sleeping in chairs next to the filtrationrig. No more fevered conversation about whether muffins will be put out in time to keep us going: the ritual of Muffin O’clock. We made it through a whirlwind two weeks of 16 hour days, sampling like people possessed, when all you had to do was keep going.

Your world shrinks when you are at sea. You make friends quickly. You acclimate quickly. Muffin O’clock becomes one of the major events of the day. But there is no place for Muffin O’clock on land. Muffins are just food there, devoid of their symbolism, their ritualized anticipation. Simple things get lost in the transition back to the richness of our lives. Now we are coming back to reality. We are remembering loved ones, as if for the first time. We are organizing events once the ship docks. We are filling hours we had forgotten we even had. We are eating Oreos for pleasure, not survival.

Written by Ben Knowles

NAAMES-III Expedition: September 12, 2017

September 18th, 2017 by Kristina Mojica

Sleep.  I don’t mean to say it is taken for granted, but it is dependable. Dependable in the sense that after the day’s activities, we go to sleep. Each and every night.  That’s how it works at home at least.  Here on the ship, work is being conducted 24 hours per day to get the most out of our short 26 day cruise.  The detailed happenings of each day are different and a “full” night’s sleep generally comes in two or three (or more!) segments and is not necessarily during the nighttime hours.  The daily challenge becomes fitting these sleep segments around the required work.  And regardless of the sum total hours slept, two 3-hour segments is never equivalent to one 6-hour stretch.

The scientists and crew onboard R/V Atlantis have all manner of daily schedules.  For many, including me, the day begins by waking around midnight in order to be ready for the first water sampling by 1am.  Work begins in earnest and continues throughout the day until later in the afternoon.  Thankfully, some days are a little lighter than others, but there is always more work to do.  If not collecting or processing samples, then recording and transcribing sample logs, analyzing data where possible, helping others, troubleshooting problems, and preparing for whatever comes next.  The Plan of the Day (POD) is posted each day and provides the necessary structure for the day.  When things are going well, the POD is predictable, thus sleep is predictable as well.  However, any changes to the POD often require changes to sleep schedules.  Imagine not knowing when your sleep will come in the ensuing 24 hours!

The infamous Plan of the Day (POD).

We force ourselves to take a nap when it fits.  This is not always successful because of a racing mind, daylight hours, interruptions, or the constant bump and buzz of the ship.  Of course, sleeping becomes even more difficult during rough weather.  Luckily, we have had great weather on this particular cruise, excepting our entry into the North Atlantic in the wake of Tropical Depression Ten (it didn’t develop into a named storm, but still provided some exciting weather right out of the gates).

Blog author Toby Westberry trying to catch some sleep in between tasks.

One critical decision that those who share my schedule are faced with toward the end of each day is whether or not to stay up for dinner!  Going without allows a bit of extra sleep, but also means no real food until the following breakfast.  Yet, while it can be satisfying eating a big meal moments before lying down to sleep is the greatest idea either.  Well, you can see how even simple decisions like this are more difficult than they should be after long, oddly placed work hours.

Of course, there are some benefits to being awake more and during the wee hours.  A sense of comradery exists amongst those who work the “night shift”.  We see each other in all states of being: bleary eyed, unshowered, bed-headed, half awake, etc.  Sunrise viewings are a daily affair (when not cloudy) and always provide new energy.  Early morning baked goods taste better than ever after working up an appetite all night.

Sigh …….Despite all that, you’ll have to excuse me because I’m going to try and get some sleep now …

Written by Toby Westberry

Notes from the Field