Sunday, July 17, 2011

Winding Down

This cruise is coming to an end.  The science party and crew are excited to get back to solid ground.  Scientifically, we achieved nearly all of our goals and collected a great data set for studying air-sea gas exchange. The process of analyzing the data will continue once we are back home.  In the process, we have learned a lot about our own measurements and those of the other groups on the cruise.  Bringing in a diverse group resulted in new collaborations and discussions of future research.

For us, the blog has been a way to document this experience, and to keep family and friends updated on where we have been.  It has also been a way to communicate what we do to a broader audience.  The blog has been more successful than expected.  Over the course of the cruise we had over 1600 hits from 10 countries.  Having a lot of young scientists onboard who are savvy with social media was helpful.  Thanks for reading and sharing this experience with us!
Complete BLOOMCRUISE 2011 track totaled more than 7500 km.

Saturday, July 16, 2011

Sensory Overload

- Phil Bresnahan

Life on a research vessel is a strange conflation of simplicity and almost overwhelming stimulation. On the one hand, it’s essential that we bring only what we need to avoid excess clutter. In the labs, we tend to bring spare components for just about everything possible in preparation for the inevitable malfunctions but there’s always much more that we need to leave behind (such as our highly-inclined-to-seasickness advisors). Personal belongings are even more constrained:
-“Hey, isn’t that the same shirt I saw you wearing a few days ago?”
-“Um, nope. That was yesterday…”
Despite our attempt at modest packing, though, the sensory environment on board is far from limited, in every category.

Let’s start with taste. Mike, Erskin, and Thomas have done a deliciously fantastic job of fattening us up with every style of cuisine and an incessant supply of desserts and freshly baked breads (we have regularly scheduled breakfast, lunch, and dinner, a snack before lunch, cheese and freshly baked bread before dinner, and an evening snack every day—I’m not kidding). I have a difficult enough time making my meals taste fresh after I’ve had the food stored for a week so I’ve been amazed by how fresh everything has been here, especially now that we haven’t seen land for three full weeks. I am very impressed with the variety, too. I expected to be eating variations of the same meals after the first few days but I don’t think I’ve seen the same thing twice at any lunch or dinner. Matt talks about this culinary phenomenon more in his post, below.

In the olfactory and vision categories, the stimuli can bring either a flooding calmness or an emptying loneliness. We see the same ship, same faces, same clouds, and same five foot waves every day, accompanied by an irreplaceable smell that only the open ocean can bring. At times, this can be the best combination imaginable. It’s quite peaceful to be out in the middle of nowhere with new friends and an infinite view of the horizon yet there are times when it’s easy to forget the soothing feeling and wish to be back on land, back in a more familiar setting where it’s possible to walk more than fifty steps in one direction (without falling off of a boat into near-iceberg-temperature (or, freezing) water).

The feelings sensed on board can create some strange problems. With the ship’s constant rocking, the disconnect between what we feel and what we see can be quite an uncomfortable combination. Even for those who don’t get seasick, it takes a few days to get used to the rolling and pitching. And no matter how much you adjust to the feeling, it’s simply impossible to learn how to predict the onslaught of every rogue wave and avoid stumbling into the nearest wall. These waves, by the way, have an incredible ability to know exactly when you’re carrying soup or a recently refilled mug of tea.

And finally, we have the sounds, without a doubt the most overwhelming of the five. A complete list of these would span pages, so I’ll highlight just a few. The obvious ones include the sound of the water buffeting against the hull, the whirring of the motors in everyone’s instruments, and the steady hum of the ship’s engines. The ones for which I wasn’t as well prepared include the cacophonous drilling, rust removing, sanding, and paint chipping of the non-stop boat maintenance (don’t get me wrong, I’m not complaining, I’d much prefer a well-maintained ship and a little extra noise than the opposite), the gym’s radio dialed all the way up, the fog horn that blasts every two minutes, Cyril’s chatter, and, of course, the dragon. We must have acquired the dragon when we were up near Iceland (naturally). The dragon’s quarters, apparently, are directly below mine and she is clearly not happy to be on board. She intermittently roars loader than I could have imagined possible, bangs into the walls, and occasionally hisses (letting the built-up steam escape, presumably). I mentioned my discovery to the Captain and he looked at me strangely and quickly mumbled something about stern thrusters, large waves hitting the hull, and the engine’s cooling system. I shouldn’t be surprised; I’m sure I’d manufacture a response like his too if I were trying to smuggle a dragon into the United States. Anyway, this new addition to our ship has kept me wide awake during the past two nights, it being far too noisy to consider sleeping or even thinking, for that matter.

After three weeks of nonstop sensory overload, I’m looking forward to a real bed in a silent, dragonless room but I’ll certainly miss the peacefulness of the open ocean. Twenty-four hours left! (But who’s counting?)

Thursday, July 14, 2011

Hardtack and spam

- Matthew Czikowsky

One of the first questions I’ve been asked about being at sea is “How is the food?” Well, contrary to what might come to mind, anything but what’s on the title of this post, even after over two weeks at sea! Actually, the food has been quite good, with a wide variety of meat, fish, fruits, and vegetables at each meal, and don’t forget the dessert and fresh-baked breads! Here’s a sample menu I penciled down from last Sunday’s dinner:

Braised leg of lamb with its own sauce
Lightly breaded grouper fillet
Summer squash steamed in white wine
Confetti rice pilaf
Cauliflower with green onion
Mixed fresh fruit compote baked with filo pastry

Photo courtesy of Brett Stacy

Pictured above was the Fourth of July Dinner which featured King Crab Legs and Prime Rib, a very nice meal indeed!

While at sea meals are served promptly at 0730-0815 (breakfast), 1130-1215 (lunch), and 1700-1745 (dinner). Since most of the day people are working in their respective parts of the ship, either in one of the labs, lab vans, or out by the mast, the meal times also provide a time for folks to get together and take a break and discuss how their day is going, or just about anything else!

Back in Woods Hole while unpacking and starting the setup for this cruise, we heard the call “All hands on deck” and we saw that the pallets of rations for this cruise were being craned on deck. Members of the science party helped the crew to form a human chain and where we passed along every box of food and supplies needed for this cruise along the line from the deck down to the ship’s storage hold, including flour, sugar, eggs, drinks, potatoes, etc. Without any stops at port, these supplies were everything that was going to keep us going for this month. Hats off to the Steward’s Department for their fine work in preparing fine meals from these supplies during this cruise!

Tuesday, July 12, 2011

Q & A

- Phil Bresnahan

Some of our many fans on land have been e-mailing us with questions pertaining to this trip, so I’d like to take a moment to answer them. It's hard to respond to all of you out there, but I'll do my best.

Q: Have you seen any interesting wildlife?
A: There is an amazing number of seabirds out here. They’re everywhere you look. This caught me by surprise, expecting to find a vast emptiness in the middle of the Atlantic. We’ve seen a few gaggles of pilot whales passing by (up to fifteen in a group!) and there was a swarm of bottlenose dolphins this morning. We were rolling around in the twenty foot swell and they just came over to check us out and play in the waves. We occasionally capture some copepods, nearly-microscopic zooplankton whose name means “oar feet” (fun fact of the day—you’re welcome), in our testing systems as well. It’s very nice to see other living creatures out here so that we have something to look at other than clouds, waves, rain, and Cyril (see photo below (just kidding, we love Cyril!)).

Q: What do you do for fun?
A: Science!

Q: No, seriously…
A: Oh, well, there are a few recreational options on board. We have a nice movie theatre with a selection of over five hundred movies, very up to date. We watch one movie every day. There is a small gym with space for about two people at any given time, but plenty of options (bicycle, ergometer, free weights, pull-up bar). We also play the British pie game occasionally or listen to Vasili shred it up on the accordion. My favorite thing to do is hang out on the bridge with the captain and mates and listen to some of their stories that they’ve accumulated—and sometimes embellished ;-) –over many years at sea.

Q: What shift do you have to work?
A: I have the blessing and curse of running my own automated equipment; when things are working properly, I can relax but when they’re not, I have to figure out how to fix them. In other words, I’ve had days where I’ve essentially finished working before dinner and others when I’ve still been puzzling over problems until 3am, if not later. I’ve woken up before 6am to start work and I’ve slept until 10:20 (quickly awoken by our weekly fire drill which, unfortunately, slipped my mind until I heard the ship’s alarm bell buried seemingly somewhere inside my skull).

Q: Is most of your work self-contained or is the labor on board shared?
A: A little of both. As I mentioned above, my project is independent, but certainly related to the other work on the ship. We all try to help each other out when possible, share components, and compare data patterns. Most people on the ship are with larger research groups and many of them have collaborated before. The crew is always around to help us if we have specific needs with which they can help us. The bottom line is that there is always someone willing to offer a helping hand.

Q: Do you miss me?
A: Yes, of course.

Bonus question: What is the escutcheon?
A: Hmmm… a good one for parties. Where did you learn that word? Escutcheon, according to the Wikipedia, has many meanings, several of which I will not write here. However, I think the one which you were going for is “a plate on the stern of a ship inscribed with the ship’s name.” Apparently, that is the least commonly used meaning of the word, following “coat of arms,” “an item of door furniture” (sic… door furniture??), “a decorative plate that surrounds a faucet,” other decorative material, and so on…

That's all for now. We love hearing from our fans, so if you have more questions/comments, send 'em over!

Saturday, July 9, 2011

Storm Forecast Update

- Scott Miller
The forecast storm should begin early Sunday morning with 30+ knot sustained winds for 36 hours.  Figure 1 shows the extreme surface wind forecast index for Monday.  At our location (the “x”) we are high on the index.  We are looking forward to collecting the high-wind data, but not to the conditions on the ship during the storm.  There will likely be a lot of motion to deal with, though we will be on station and not underway, which reduces the motion.  It is important to note that these ships are designed to operate in these conditions and do so all the time, so it is not dangerous.   Hopefully the equipment will survive the storm!

Friday, July 8, 2011

Sea Changes

During this cruise, we have already seen some marked changes in the physical appearance of some of the science party. We have therefore re-taken the personal photos of the science team (Figure 1). Feel free to compare with the pre-cruise science team photos (Figure 2) to see what a few weeks at sea has done to us!

Figure 1.  Science team after 2 weeks at sea.

Figure 2. Science team before cruise.

Thursday, July 7, 2011

Making the Plan

--Scott Miller (SUNY Albany)

The science team meets nightly in the Knorr Theatre to discuss the current status of the measurement systems and to shape the sampling strategy for the upcoming days.  Since a main goal has been to find a high-DMS phytoplankton bloom (see Tom’s earlier post), the ship track is a topic of nightly discussion.   
The remote sensing images (e.g, chlorophyll – see Fabricio’s post) are displayed on the bigscreen TV, and we spend a fair bit of time trying to understand what’s in the images (besides clouds), and to project where we can find high DMS and high dpCO2 (see Matt’s post).  The recent image shows our ship track (Figure 1, thick black line), with 24-hour periods on stations marked with an “S”.  As Tom will detail in a later post, we eventually found a high-DMS bloom at station S4.  Great news!  

Figure 1. Chlorophyll-a
So, you might think that after searching for 10 days and finding the bloom we would remain in it to sample for an extended period.  But… we also need to consider the weather.  We are trying to collect data over a broad range of conditions (i.e., wind speeds) to better understand factors controlling gas exchange.  Figure 2 shows results from our 2007 cruises.  You can see that most all of our data is for wind speeds below 10 m/s (or about 20 knots).  During this cruise we would like to extend this to higher wind speeds where whitecaps are thought to be important (see Brett’s post).   

Figure 2. Knorr 2007 results.
The weather forecast for the next 4 days at station S4 predicts very low wind speed (below 15 knots) – not interesting for our measurements.  Alternatively, the forecast for our next station (S5, 50N, 048W) is more “interesting”, with a low-pressure system moving in and the potential for gale force winds.   So, we are now in transit with an estimated arrival time at S5 of Saturday morning.  The low pressure system is projected to pass over that location on Sunday and Monday.  Stay tuned…

Wednesday, July 6, 2011

An argument

- Joao Almeida [NUI Galway]

Believe it or not, the ocean and the atmosphere are having a chat. And we’re out here to listen to their conversation. We want to hear their arguments, for we have good reasons to think that what they’re talking about concerns us all. They sure speak in mysterious ways, whispering most of the time. And before we can understand them we must understand the syntax of their language, which is a much easier task when we can hear them talking out loud. That’s what brings us here, in this very region of the North Atlantic at this very time of the year, where the atmosphere sometimes screams at the ocean.

So all we need is a sophisticated headset, to allow us to listen to the very specific range of frequencies they both use to communicate, and a recorder, so we can listen to their dialogue later and eventually translate it. What we need also is one big boat with a crew, to carry our gear on site and bring us - the linguists, or interpreters, but mostly plumbers, by affinity - out there right where the argument is about to occur, and take us back home, safe and sound.

Our headsets can be tricky to handle, for they conduct air and seawater, and sometimes we even have to throw them out in the ocean and leave them there overnight, trusting them to bring us all the right numbers. Yes, numbers! The funny thing is we’re trying to understand how the atmosphere and the ocean communicate looking at numbers. And numbers constitute the most valuable currency onboard, for their scarcity, and for being the only window we have into the problem that brought us here.

That’s where it gets even trickier, or say, challenging. We’re literally trying to anticipate an ocean of numbers, permanently changing in time, by looking carefully at a handful of them. Richard Feynman once brought up an insightful analogy where he compared the work of a scientist in understanding the laws of Physics to the one of an observer of a chess game trying to understand the rules of the game by looking at a limited area of the board only. It might sound impossible but it sure is enjoyable. And it is what brings us all on this journey. Cause for all we know, and to finish with Shakespeare’s fine words , ‘The Earth has music for those who listen’.

July 4th, Independence day celebration

We are sailing on an American ship. And so we couldn't miss to celebrate the Independence day. Special lunch of the day was Pizza in all variations served with ice cold soda drinks. Then we all met on deck and burned a small firework, consisting in hand held and rocket flares. This was of course not just for fun, but rather an other lesson in safety.


Tuesday, July 5, 2011

Lessons from the crew

- Phil Bresnahan [Scripps Institution of Oceanography]

Sailing is one of the oldest professions that exists; there is indubitably a tremendous amount of wisdom contained within the collective knowledge of those who practice it. Over the past weeks on the ship, one of the crew's habits has really stood out, a way of life from which we can all learn a tremendous amount. It is what I would call focused patience. It was not entirely surprising for me to realize that the crew is focused nor that they possess some level of patience after years of being on the open ocean but this particular combination seems much more powerful than either of the traits individually. Focused patience is the recognition that there might be only one chance to get something right and therefore lending it your full attentiveness but at the same time approaching it calmly, slowly, and deliberately.

An example: every three days, we lower an 8 foot, 200 lb piece of extremely expensive equipment (ASIP – see Graig Sutherland's post below) into the water inside a smaller powerboat driven by two crew members and at least one science member. The passengers are lowered about fifteen feet over the side of the ship into whatever conditions the day has in store for them; they've been in up to ten foot waves (still small by open ocean standards, but far from negligible) and a significant amount of wind chop. The small boat swings in the crane's grip until it hits the ocean after which it is entirely at the mercy of the waves. It's a safe but still quite tense process every time.

When they return from ASIP's deployment, they have to drive up alongside our enormous ship, catch the crane hook (which happens to be a nearly fifty pound chunk of swinging metal), attach it to their own boat's harness, wait to be raised out of the water, back onto the ship, and into the powerboat's slings on the deck. This seems like a process that I'd want to rush through; extra time in this procedure is extra time for something to go wrong in a scenario where something going wrong is quite simply not an option. Contrarily, though, the crew executes this procedure with a slow, deliberate concentration every time – with a focused patience. It takes approximately three eternities to get the group from the incessant slapping of the careless waves back into the safety of the ship's deck and, every time, I want to grab the crane's controls from its operator and get the passengers out of the water as quickly as possible, then grab the lines from the deck hands and pull the boat into its slings. The first time I saw the process, I was convinced that the crane operator must have fallen asleep and that the crew on the deck had decided they didn’t want the small boat back on board after all. Maybe they’re just tired of sharing the food with these other passengers...

Yet after watching this process a few times, I've picked up a small piece of wisdom that sailors have ingrained within them from centuries, millennia even, of trial and error. They know that it is in rushing that careless mistakes are made. There are no second chances, really, so they take the time to make sure that every detail of every step is executed with absolute perfection.

It's easy to be focused, I believe, and most of us can find the capacity to exercise a little patience from time to time, but I believe it's rare that we are successful at combining the two. We either focus on getting through something as quickly as possible (“get it over with!”) or we pretend to be patient while sitting in traffic on the way home from work but these are always two separate instances. We don't focus on driving when we're trying to be patient and we're certainly not patient when we're intently trying to rush to the end of some project. I’m certain everyone has rushed through something (with or without focus) and finished with a far from perfect project.

The fact that the crew can afford to (or, more accurately, is forced to) exercise extreme focused patience while performing what is perhaps one of the most important jobs imaginable – protecting human lives in a highly variable environment – is a convincing argument for our own adoption of the practice in our lives. I think there is something to be learned from the habits of those who don’t have the luxury of the option of mistakes. A little more focused patience in all of our lives would certainly lead to higher success rates, fewer accidents, and, most importantly, a more rewarding experience along the way. So even though this process takes about seventeen times longer than my naive outlook would suggest, I now realize that it’s no accident that they don’t make mistakes. For now, I’ll leave the crane controls to its operator and watch from the deck to see what else I can learn from the wisdom of the crew.

Sunday, July 3, 2011

Nice sunset

Scientists are enjoying beautiful sunset scenery after one day's hard work. It's worthy to stand there for a while even though it's chilling outside.

Sampling CO2 in the air and sea

- Matt Czikowsky [SUNY Albany]

During this cruise, concentrations of carbon dioxide in the surface seawater and atmosphere are being monitored with the goal of continuously measuring the difference in these concentrations, known as ΔpCO2 (or delta pCO2).
The difference in CO2 concentrations between atmosphere and sea is important in terms of the CO2 flux between the surface ocean and atmosphere: CO2 levels in the surface seawater greater than those in the air (positive delta pCO2) results in a release of CO2 into the atmosphere, while CO2 levels in the seawater that are less than atmospheric (negative delta pCO2) result in the ocean taking up CO2.
The air-sea CO2 flux can be estimated by multiplying the delta pCO2 level by an empirical exchange coefficient called the “piston velocity.” Since the measured CO2 fluxes vary as a function of wind speed and atmospheric stability, the piston velocity is a function of these atmospheric variables as well. Since our group from the State University of New York at Albany is making direct CO2 flux measurements using eddy covariance on the mast during this cruise, we can make estimates of the piston velocity using these delta pCO2 measurements.

Our group is deploying two systems to measure delta pCO2. The primary system consists of an electronics box (Figure 1, built at UAlbany by Jim Albrecht) which contains a CO2 gas analyzer, valves to control system flows, and a logger to collect the data as well as a showerhead equilibrator used for sampling the surface seawater CO2 concentration. The system performs a measurement by flowing seawater from the ship’s intake into the showerhead equilibrator where it is sprayed through nozzles into a volume partially filled with water. Mixing occurs between the seawater and air in the equilibrator chamber, resulting in the CO2 level in the headspace of the equilibrator to be in equilibrium with that of the seawater. video
The equilibrated air stream containing the CO2 level of the seawater is then pumped to the electronics box, where some of the air is sent to gas analyzer, while another portion of the sample is returned to the equilibrator chamber to form a closed loop. A water manometer is located at the top of the equilibrator, which helps to regulate the pressure and water level in the equilibrator chamber. Once the seawater CO2 measurement is complete, a series of valves switch in the electronics box to allow atmospheric air from the foremast of the ship to be sampled.

Saturday, July 2, 2011

An ocean view from space

- Fabrício S. C. Oliveira (University of Sao Paulo, Brazil)

Firstly, I'd like to thank our Chief Scientist, Scott Miller, for the invitation to participate on this cruise. This will be an opportunity to learn techniques for making air-sea interaction measurements and applying these techniques in studies of the same nature in Brazil. I was extremely curious in participating on a cruise that has as its purpose measuring air-sea gas exchange, since that is totally new for me.  At the moment, I don't work with air-sea gas flux (yet), so what am I doing here?

I'm a physical oceanographer specialized in ocean remote sensing meso- and large-scale and a beginner in ocean modeling. However, if we are studying areas with high primary productivity (phytoplankton blooms) nothing is better than satellite data to monitor these blooms. The main advantages in using satellite data are the wide spatial coverage, synopticity, and the high sample frequency of the data. Regions with a high oceanic primary productivity can be easily monitored from space using ocean color images. The oceans are composed of different kinds of components, dissolved or particulate. They can be optically active, that is, interacting with electromagnetic radiation from the sun; they are responsible for the different colors in the oceans.

The majority of sensors monitoring the ocean color operate in the visible band, a narrow band of the electromagnetic spectrum that is used for us to distinguish the color of the objects. The most important application of these sensors is the estimation of chlorophyll-a concentration, because from it is possible to estimate the phytoplanktonic biomass and primary productivity in an area. Good… it seems intuitive to use this data for monitoring bloom regions, right? Gotcha!!! As nothing is perfect, a big problem is that the clouds are totally opaque to the radiation in these wavelengths and a high cloud coverage means no data. This high cloud coverage has been common along the cruise. To minimize the effect of the cloud coverage I have tried to do some simple image processing, such as an averaged composite between two different ocean color sensors.

Finally, as an oceanographer, it is fair that I participate on the team charged with making the CTD casts, the CTDers, as we are known. I'm totally familiar with this operation, but I've never seen a CTD cast so organized (congrats to the crew and SSSG team). Also, I've never seen such fast CTD casts in the deep-sea because the CTD only goes down to 100m, but I'm not complaining because the sooner the better. The CTDers are always in a good mood, event at 1am, when we are closely monitored by the squids and small fishes (maybe needlefishes, i'm not sure about that).

Friday, July 1, 2011

Just below the surface

- Graig Sutherland [NUI Galway]

By now you, our faithful blog readers, have been introduced to marine aerosols, eddy correlation fluxes, and gas transfer rates and now I’m going to tell you a little bit about why I’m here. My name is Graig Sutherland and I’m a PhD candidate from the National University of Ireland, Galway (NUIG) studying the physical oceanography in the upper ocean. Surprisingly the upper ocean, even though it’s the most accessible part of the ocean, is one of the most under-sampled regions in physical oceanography. I’m interested in the physics of the upper ocean and how this interacts with the atmosphere. To measure this we use an autonomous vertical profiler ASIP (Air-Sea Interaction Profiler), which was developed by my supervisor Dr. Brian Ward (now at NUIG). ASIP is an ideal instrument for upper ocean physics in that it profiles upwards, making measurements at sub centimetre scales, through the water column to the water surface. ASIP measures temperature, salinity (inferred from the conductivity of seawater), the dissipation due to turbulence (inferred from the small-scale shear), water velocity, ambient sound, and solar radiation coming through the water surface. These measurements can be related to effects from the atmosphere (such as wind, gas transfer, etc.) and vice versa (i.e. effects from the atmosphere can be related to physical aspects of the upper ocean).
The high precision sensors fitted on ASIP are extremely fragile and offer some challenges in how we get ASIP into the water without breaking everything. This is no small feat as ASIP is 2.5 metres long and weighs in at 100 kilograms (that’s 8 feet 4 inches and 220 lbs respectively). To achieve this we need to go out in a small boat and gently place ASIP into the water. The first photo (courtesy of Phil Bresnahan) shows ASIP (with the yellow top) getting ready to go to sea. This is usually a good time (as long as nothing breaks!) and there is never a shortage of volunteers to go out for a little scientific expedition on a small boat. Once in the water ASIP is all on it’s own to make measurements. It descends through the water with the work of three thrusters which pull it down to a pre-programmed depth at which point it freely rises to the surface. Once ASIP reaches the surface it tells us it’s location via iridium satellite so we can track it until it’s time to go out and recover it.
With just over two weeks to go there is ample opportunity to investigate air-sea interactions and to keep looking at what is going on just beneath the surface.

Oh, the beauty of a CTD cast!

- Cristina Schultz [National Space Institute, Brazil] (figures by Ryan Kennedy)

I believe all oceanographic research cruises must count on its magic to keep up the good work. It consists of sensors of conductivity, needed for the calculation of salinity, temperature, depth (hence the name CTD), and any other sensors able to help with the understanding of the vertical structure of the ocean beneath the ship. Here we are also measuring oxygen concentration and fluorescence (which helps to see where the phytoplankton are). Attached to the CTD are 24 bottles to collect water samples at different depths, and the combination of the bottles with the sensors is what we know as the Rosette system.

At sea it is easier to picture many of the phenomena that we so much study while in land: the waves, wind-forcing the water in many directions, temperature gradients forcing heat transfer between air and sea. But even when we are so used to it that the days go by following the motion of the waves instead of the clock, what lies under our feet would still be a mystery if it weren’t for the CTD.

The understanding of the big picture is a task for the CTD. Which water masses are swimming between the surface and the sea floor can easily be identified by its sensors, and the variation of these water masses is important for air-sea interaction. All that motion going on right below our feet is available for us in real-time through a computer monitor as the CTD swims down into the cold waters, rapidly increasing in pressure, to give us such valuable data.

It is surely not the only way to measure vertical structure (as you will see on Graig's post, coming soon), but it is used as a guide for the other measurements going on at the cruise. Once the CTD has explored the water column’s gradients we can evaluate how certain properties should behave and at what depth other measurements can get what they are looking for.

On our cruise we are not torturing the CTD with hours of cold water and intense pressure until it almost reaches the bottom. We are doing casts only to depths of 100 meters (length of an American football field). By profiling to this depth we can see what we call the 'mixed layer': a layer of water where temperature and salinity (from which we can get density values) are quite homogeneous. This layer’s characteristics can be determined by temperature gradients between air and sea, and wind forcing. In the fluorescence signal, we see how the attenuation of light by the water makes it hard for phytoplankton to synthesize chlorophyll. Oxygen (and also CO2) is affected by the values of salinity, which “competes” for space in the water, temperature (the colder, the more gas can be dissolved) and by phytoplankton respiration and photosynthesis. So yep! A lot of processes are seen with much excitement on the screen!

Today, as we moved north from where we were yesterday, the mixed layer got a little bit deeper (it is still around 20 meters), but the phytoplankton, that had been hiding below it, probably protecting themselves from too much turbulence or light, have approached the surface by inhabiting the mixed layer.

We do daily casts at 1 pm, and a cast every 6 hours when on station. So, on 24 hours of station we can get 5 casts, and that helps to see how heat transfer and wind can change the mixed layer on a daily basis at the given latitude.

Interesting changes perceived by our casts will be reported to the blog as soon as we see them!


- Brett Stacy [Humboldt State University]

When one imagines the open ocean, they may picture it as a constantly dynamic and often ferocious landscape. With huge crashing waves, high speed winds, and ship-dwarfing storms. Even looking at the background to this blog gives a viewer that impression. One of the many goals of this cruise is to document one of these features of the ocean, moreover the effect of one of these features on the state of the sea surface: The wind and the white caps they induce.

White caps hold special significance to our world. Besides being a surfer’s worst enemy and a kite-surfer’s best friend, white caps have a profound influence on, you guessed it, climate change. They contribute to gas exchange between the ocean and atmosphere, they affect the reflectivity of solar radiation reaching the earth’s surface, and they serve as a visual byproduct of the transfer of energy from wind to ocean surface currents.

Throughout this cruise, my job is to quantify the proportion of white caps covering the sea surface in order to later relate their influence on relative flux measurements between and DMS made by others on the ship. How do I do this? Using state of the art cameras mounted on the highest point of the ship, images of the sea surface and the white caps on it are automatically collected once every second during the daylight period. These images are then processed to discover what proportion of their contents include white caps. The process includes converting the image to black and white, with a threshold for the color white determined by observation of the color characteristically exclusive to white caps. The final result is a White Cap Fraction (WCF) for each image.

Being the ocean’s personal photographer has been a blast. Participating on the Knorr in general has been great. This cruise is my first time on a significant (more than one day) research voyage and so far it’s been an adventure. Every day something interesting happens and new challenges arise bringing everyone on the ship closer together. It has only been one week on the Knorr since leaving Woods Hole, but already it feels like we are all part of a big family. Every ones’ positivity and enthusiasm makes life at sea fun and easy-going. I can’t wait to see how our family develops and what exciting events are in store for us at higher latitudes!