After just over a full week at sea, we have found the rhythm of our life and work routines. We collect water with the CTD rosette, deploy instruments over the side of the ship, work in the lab, eat, and sleep. That might sound like a lot of work and no play, but we do manage to have fun while we work (think lab dance party while filtering water samples). We’ve also taken time to observe the vast blue around us from the upper deck of the ship, where we recently watched a gorgeous sunset. No green flash sightings yet but I continue to hold out, hoping to see this optical phenomenon – a green flash of light that can sometimes be seen just before the sun disappears below the horizon.
Left: View of the sunset from the top deck. Right: Deck operations just after sunset, which includes deploying two instrument packages that measure a variety of optical parameters, and the CTD rosette, which collects water samples from different depths. Credit: Ali Chase
Several days ago we crossed into the Sargasso Sea, which is an area of very clear blue water due to low amounts of phytoplankton and dissolved matter which absorb light and make the water in some areas, such as coastal regions, a greener color. But here the water is an amazing deep blue color, which is the color of ocean water when there is not much there besides the water itself. One life form that is prevalent is a seaweed called Sargassum, which we frequently see floating by.
The very blue water of the Sargasso Sea, with a few floating pieces of Sargassum. Each piece is roughly the size of dinner plate, for scale. Credit: Ali Chase
Speaking of things that absorb light in the ocean, much of the work we do in the “wet lab” is related to the absorption and scattering of light by different particles in the ocean. This optical oceanography work allows us to measure the way light interacts with particles, in particular phytoplankton, which absorb and scatter light differently depending on the types and amounts of phytoplankton present. Throughout this cruise we are collecting water continuously using a system involving a boom that extends over the side of the ship with a hose hanging from it into the water. A pump on deck constantly brings water from approximately three meters depth through the hose and into the wet lab, where it then flows through several instruments and provides us with constant information about the optical properties of whatever is in the water.
But, the ocean is a massive place, something that we are very much reminded of while working at sea with no land to be seen in any direction. Even sampling the water continuously during this three-week trip will just give us a small snap shot of ocean conditions. This is where satellites come into play, as they can provide a much broader spatial view of the world’s oceans. However, work in the field is necessary to “ground-truth” what the satellites tell us, to be sure that such expansive information can be accurately related to what is present in the ocean. During this research cruise we will pass through several types of water, such as the warm/salty/fewer phytoplankton water like we see here in the Sargasso Sea, versus cooler/nutrient rich/lots of phytoplankton water in coastal areas such as the Gulf of Maine. Understanding the differences between these regions can be useful for interpreting satellite information about phytoplankton and their role in the earth’s carbon cycle.
Left: The flow-through intake system; the hose hanging from the end of the black boom sucks up water continuously using the pump located in the black box on deck. Right: The wet lab in all its glory – the tubing with the water pumped from outside can be seen running up near the ceiling; it then flows through several instruments positioned both in the sink and on the bench top. Credit: Ali Chase
A couple of days ago a storm system passed over us, and the winds came up to about 30 knots. With winds that high, waves crash onto the deck and it is unsafe to deploy instruments over the side of the ship, so our work was put on hold for a day. I spent some time on the bridge (where the ship’s captain and crew navigate from) and watched the bow of Endeavor ride the waves like a roller coaster. Every now and then the bow came down against a big wave and an impressive spray of ocean water was sent flying, with water reaching as far as the windshield of the bridge where we were watching!
The ship crashes into a large wave during high seas. Credit: Ali Chase
To document our work and life on board we have been putting GoPro cameras on everything, including hard hats and instruments that are deployed over the side of the ship. Recently a GoPro went for a ride on the “Polarimeter”, an instrument that measures the polarization state of light, which Robert mentioned in the previous blog post. While the GoPro was underwater, a big group of dolphins came to say hi, and the GoPro caught it on camera – very cool! We also lowered Styrofoam cups down with the CTD to a depth of 1,000 meters, where the pressure compresses them, along with any writing or pictures that have been drawn on. We sent down a bunch of cups from a school group that had visited the University of Maine’s Darling Marine Center, and we added a few that we decorated ourselves for souvenirs to bring home.
Left: A selfie I took while wearing the GoPro on my hardhat. Credit: Ali Chase; Right: Dolphins near the Polarimeter deployed with a GoPro attached. Credit: Wayne Slade
Styrofoam cups that were attached to the CTD and lowered to 1,000 meters, where the pressure compresses them (top = before, bottom = after; box of tea shown for scale). Credit: Ali Chase
I feel very fortunate to be included in this adventure at sea with such a great group of scientists and crew. I am constantly learning about the ocean and how we understand it as oceanographers, as well as all of the techniques and logistics that go into the collection of quality data. It is certainly humbling to be out on the ocean with nothing but blue all around, and I am reminded of why I am drawn to this field of study and how much of our planet is covered in this blue expanse. Thank you for taking the time to read our blog and I hope you’ve enjoyed this glimpse into our life and work at sea!
Ali Chase is a graduate student in oceanography at the University of Maine’s School of Marine Sciences.
Text by Robert Foster City College of New York – CUNY
Here we are ending the 4th full day aboard the R/V Endeavor, and I can hardly believe it! Time really does fly when you’re having fun! Amid the rush of running cables, installing sensors, learning new and exciting science and making new friends, I couldn’t be happier. I am a 3rd year Ph.D student in the Electrical Engineering department of The City College of New York, and through extremely fortunate circumstance I found myself working in the Optical Remote Sensing Lab of NOAA-CREST.
Life aboard the R/V Endeavor is both exhilarating and exhausting! During our safety briefing I jumped into an immersion “Gumby” suit for the first time, giving my colleagues a good laugh as I tried to close the face flap with my lobster claw gloves.
I’m trying on the immersion suit for the first time and posing “mannequin-style” for the safety briefing Friday morning. Photo courtesy of Ivona Cetinic, University of Maine
Although we’re currently 18 miles off the shore of New Hampshire, we’ve already had several visitors!
On Saturday morning we spotted a pod of whales in the distance. They were too far away to photograph, but we could clearly make out their sprays and tailfins when they dove.
And the dolphins! This was the best part. Just a couple hours after leaving port on Friday the entire science team was on deck learning how to deploy the CTD when a pod of dolphins started leaping out of the water not 20 feet from the ship! It was almost as if they wanted to see us off on our journey! We managed to snap some really fantastic photos.
Dolphins jumping out of the water to see us off! Photo courtesy of Ivona Cetinic, University of Maine
Slightly more numerous than dolphins are the tiny phytoplankton which provide us with so much of the oxygen we breathe. Inside Endeavor’s main lab is an amazing instrument that can actually take pictures of these microscopic creatures and count them! Since one of SABOR’s primary science goals is to quantify how much carbon is being converted into oxygen by marine life, it is vital that we know exactly what species are present and in what concentrations.
Of course it’s impossible for the R/V Endeavor to be everywhere at once, so we must rely heavily on satellite observations. Current sensors such as MODIS (Moderate-Resolution Imaging Spectroradiometer) aboard the Aqua satellite and VIIRS (Visible-Infrared Imaging Radiometer Suite) aboard the Suomi NPP platform are designed to observe the ocean and atmosphere. Although they do it quite well in a general sense, there is still too much uncertainty to make absolute assessments of climate change and carbon cycling.
When we as humans look at an object, what is it that we’re actually seeing? (No, it’s not a philosophical question!) We see color and brightness. Seems sufficient, doesn’t it? But it turns out that there is actually another hidden property of light that we can’t see with our eyes, and it’s called polarization.
So if we can’t see the polarization of light, why do we care about it? Why is it a major focus of SABOR? The answer is because it’s becoming more and more difficult to increase the accuracy of satellite measurements using color and brightness alone. By incorporating polarization into our measurements, we are opening up a whole new dimension of information that was previously inaccessible. Our laboratory at the City College of New York is studying the way light becomes polarized in various conditions both above and below the surface of the ocean.
The first of the two instruments that we designed at City College is called HyperSAS-Pol. It is designed to automatically look at a fixed angle relative to the sun, regardless of the direction the ship is facing. HyperSAS-Pol measures both the polarization of sky light, and also light coming from the ocean.
I’m setting up HyperSAS-Pol on the bow tower of the R/V Endeavor. Photo courtesy of Alex Gilerson, City College of New York
Our second instrument floats on the surface of the ocean and measures the polarization of light underwater. We can rotate the instrument by using propellers that are attached to its arms. The sensors themselves are attached to a stepper motor which can look up or down in the water. With these two motions we can measure polarized light in any direction. By the way, this instrument doesn’t have an awesome code name like HyperSAS. We just call it the polarimeter… pretty boring name, I know. Maybe you can think of a better one? Post a comment!
Our floating polarimeter. Photo courtesy of Alex Gilerson, City College of New York
While we are taking measurements on the R/V Endeavor, a plane will be crossing our path several times with a sensor capable of measuring polarization, as well as a LIDAR. During their test flight on Sunday afternoon we were able to watch the plane corkscrew down from the clouds to circle the ship! Too cool. They even took a picture of us!
The NASA Langley plane circling the R/V Endeavor on Sunday afternoon. Photo courtesy of Wayne Slade, Sequoia Scientific
The R/V Endeavor as seen from the sky! Photo courtesy of David Harper, NASA Langley Research Center
Between the combined efforts of everyone onboard the R/V Endeavor and in the sky, we will be able to trace the complete path of polarized light coming from the sun, down through the atmosphere, into the water, interacting with all the little sea critters and finally emerging back into space to be captured by one of NASA’s Earth Observing satellites. If successful, our work here will be instrumental in the design of next generation satellites, such as the PACE mission.
We have one final visitor who is here in spirit, and his scientific value is without doubt. He makes sure that no light gets reflected off the white buoys and contaminates our underwater sensors. He is a childhood friend of mine, but I’m sure that you’ve met him before too!
Our very special colleague. Photo courtesy of Chris Armanetti, R/V Endeavor
Starting July 2014, scientists with NASA’s Ship-Aircraft Bio-Optical Research (SABOR) experiment will make observations from ship and aircraft off the U.S. Atlantic Coast aimed at advancing the technology needed to measure microscopic plankton in the ocean from space. For the next three weeks, follow SABOR researchers as they work toward finding out how and why plankton are changing around the planet, and where the carbon associated with plankton goes. Plankton play an important part of the climate system and deliver oxygen to the atmosphere, absorb carbon dioxide, and form the base of the marine food chain.
The following post is by Nerissa Fisher
Oregon State University
Clockwise from top left: a zooplankton species with a thalssiosira chain in the background; Paralia spp.; a colony of what may be dinoflagellates, and; a ciliate in a protective house — it is most likely that the ciliate ate the phytoplankton that made this outter shell and it now using the shell for protection against zooplankton.
Only three days until the SABOR cruise and I couldn’t be more excited! I have just finished my first year of graduate school in the Microbiology department at Oregon State University where I am pursuing my Master’s degree. I have been on several cruises before, one in the Gulf of Mexico and a couple in Bermuda, but this will be the longest cruise I have ever been on. This is also the first cruise where I have not worked at the research station where the cruise departs, so the entire process of preparing and packing for this cruise that is on the opposite coast has been a much different experience. In past cruises I was not so involved with preparation and my biggest concerns were making sure I had the right clothes and shoes for ship work or the packing list had already been determined and I made sure everything on the list got on the ship. Our research team has had several meetings to discuss the experiments and materials we need to pack. It seems like no matter how far in advance we started packing for this cruise we are still shipping boxes to the east coast. Silly things, like making sure we have beakers to mix solutions in, and all the little knick-knacks that are required for experiments have to be thought of in advance, because once you have left the dock there is no supply closet to run to if materials are missing.
Our research group is measuring how efficiently light energy is converted into phytoplankton biomass. To do this, we are making a number of different measurements simultaneously. Some of these measurements use a state-of-the-art flow cytometer, some use radioisotopes, and some are much simpler and involve filtering seawater and measuring chlorophyll, the pigment that phytoplankton use to absorb light for photosynthesis.
My life in the days leading up to this cruise has been most exhilarating. This past Friday and Saturday were completely booked doing phytoplankton bio-fractionation experiments for my thesis research. I wanted to finish those experiments so that I have data to analyze while on the cruise. Then Sunday, I absolutely HAD to watch the world cup final, which was a fantastic game!! As often as I could pull my attention away from the match, I was also sewing garments that will be used to shade seawater incubation bottles that will allow me to measure primary production at various light intensities.
An SEM picture of Thalassiosira pseudonana provided by Alfred Wegener Institute.
Ok, so maybe this doesn’t sound all that exhilarating, but I love phytoplankton ecophysiology, and I could not be more excited to have this opportunity to be at sea for three weeks collecting data that could provide much clearer insights into marine carbon cycling and meet other scientists in the same field. I will have a unique opportunity to apply the measurements I have collected for my research in the laboratory to understand how photosynthetic energy is allocated to different cell compartments, to field samples. This work could potentially be the second chapter of my thesis and broaden my current findings for a single diatom species (Thalassiosira pseudonana, see image above) to natural populations. Without these amazing primary producers of the sea, life on Earth would not exist as we know it and I can’t think of more important work than trying to better understand their physiology, especially in a world that is changing more rapidly than ever before. I am ready to be surrounded by great people, fun, yet exhausting, experiments, and nothing but blue.
A beautiful day in the trade winds zone, with its typical cumulus clouds.
From the shipboard perspective, all we really see of the sea is the surface. Of course we can see into the water a short way, right close to the ship, but not very far. The horizon is 360 degrees and the great dome of sky seems endless.
Being that we are about a thousand miles from the nearest port, it is also fair to say that all we see from the ship is sea surface and sky. These are the shades of blue that I referred to in an earlier post. When this is all one has to see aside from the Knorr, our shipmates, and interesting oceanographic data (OK, we watch movies too!), it should come as no surprise that everyone becomes sensitive to the moods of the sea and sky. When you want a moment alone, the likely place to go is on deck, and there you are confronted with some new variation of the sea and sky.
We are working in what is called the trade winds zone. It is a belt of generally east and northeast winds north of the equator and east or southeast winds south of the equator that are quite steady and global in extent (in the days of sail, one’s trade depended on using routes through these reliable wind zones). In the trades zone, we might expect relatively steady 10-15 mph winds and fair skies with broken clouds. One characteristic of the fair weather cumulus clouds in the trades is that they lean over because of wind shear in the atmosphere. The blue sky dominates the evenly scattered puffy white leaning clouds that seem to all have the same base (maybe 3,000 feet above the sea).
The trade wind cumulus clouds break up the bright shades of blue on the sea surface by casting rapidly evolving shadows across the sea. The color of the sea surface certainly depends on the light reflected from the sky (a gray sky can give the ocean a grayer look) but also depends on the intrinsic color of water, which is blue.
We had few days where there seemed to be a pink hue to the sky (especially at the low sun angles of morning and late afternoon). This is likely the result of having more Saharan dust suspended in the atmosphere. It is quite common for dust storms to carry thousands of miles out over the ocean.
Sunset in the Sargasso, with hints of Saharan dust.
The color of the water depends on the angle at which you view it and the height of the sun. One of the cool things I see in the open ocean is that when you look down into the deep waters in the middle of a sunny day there is a radiation of sunbeams seemingly coming back at you from the depths. It gives the blue ocean a kind of jewel-like quality.
SPURS Chief Scientist Ray Schmitt has been thinking about the salt in the ocean for a long time. He did his PhD thesis on an unusual form of mixing called “salt fingers,” which we will discuss in a later post. This small scale mixing process led him to consider the origins of the ocean salinity contrasts that we see around the world.
It’s fairly obvious that salty waters arise from high evaporation regions and fresher waters originate from high rainfall areas or river flows into the ocean. But it turns out that accurate estimates of evaporation and rainfall over the ocean were hard to come by. For a long time, it was a relatively neglected research topic. Many meteorologists were only concerned about how much it rained on land and few seemed to care if it rained on the ocean. Pulling together the best data he could, Ray found that, in fact, the ocean completely dominated the global water cycle. The terrestrial part, so important to us on a daily basis, is a much smaller piece. The oceans hold 97 percent of the Earths free water, the atmosphere only 0.001 percent. The oceans provide 86 percent of global evaporation and receive 78 percent of all rainfall. The total of all river flows into the ocean sums to less than 10 percent of global ocean evaporation. Clearly, if one wants to find out what the water cycle is doing, one should be looking at the oceans. The traditional fixation on the terrestrial water cycle is understandable, but risks missing the big picture. It seems that the tail is wagging the dog in terms of research on the global water cycle!
A traditional view of the water cycle.
The oceanographers’ view of the water cycle.
Of course, one of the most important questions for climate change is what the water cycle will do with continued warming. Basic physics tells us that a warmer atmosphere will hold more water vapor, so an intensified water cycle is expected. Oceanographers should be able to assess any trend in the water cycle if we do a good job in monitoring ocean salinity. On land, man has altered every watershed with dams, groundwater irrigation, deforestation and human consumption. But the ocean’s mostly unaltered and its salinity field provides insight into the vast majority of the pristine natural water cycle. The ocean has its own rain gauge in the form of salinity, and our task in SPURS is to learn how to read it.
The combination of the global coverage from Aquarius for surface salinity, detailed process studies in the ocean like SPURS, and sophisticated high-resolution computer models working in concert open up the oceanic water cycle to careful scientific examination.
Aquarius salinity data from the first week of September 2012. (Credit: Oleg Melnichenko at University of Hawaii IPRC.)
A SPURS Waveglider begins its journey to study upper ocean salinity.
We are beginning to deploy the array of instruments on the ship and they are starting their year-long mission to examine the ocean salinity variations. Our challenge is to understand the detailed picture of salinity that will be painted by the various sensors and to make sense of this in the larger picture of the global water cycle.