Notes from the Field

Expedition Planning and Flying Fish

October 23rd, 2017 by Eric Lindstrom

I try not to make this blog a travel diary, but sometimes an event is worth a sidebar. So, before I launch into words about our voyage planning, I must tell you about the flying fish.

No matter how many times you go to sea, flying fish are a wonder of nature. Just the fact that we see individual fish scooting above the surface for long distances (many 10s of yards) is amazing enough. However, there are times when the deep blue surface of the water transforms to a shimmering silver and miraculously turns into hundreds of small flying fish launching themselves as one in the same direction. It’s amazing to watch and hard to capture on film from a moving ship. The fish don’t fly as much as glide with “skitter,” as they touch the water intermittently and then buzz their tail at the surface like an outboard motor. With this added energy they keep themselves gliding above the water surface using their outsized pectoral fins as glider wings. They must have a tough life—with large fast fish like tuna and mahimahi stalking them from below and birds stalking them from above. However, they must have a keen sense for when to be in the water and when to launch into the air—and evolution has provided them with the means to act on the threats. How they coordinate their mass takeoffs and landings as a school is, I would guess, a mystery. It is certainly awesome!

Kyla Drushka, chief scientist.

So, I digress! Our Chief Scientist, Kyla Drushka, from the Applied Physics Lab at University of Washington has been coordinating planning and logistics for this voyage for about a year—since the end of the SPURS-2 deployment voyage in 2016. She has a complex assignment because there are 24 distinct scientific instruments or suites of instruments aboard the vessel—each with a different responsible scientist either ashore or aboard. Coordination of the sampling from all these instruments and how it interacts with the location and speed of the ship is the primary job of the chief scientist. It is akin to conducting a symphony orchestra of oceanographic measurements—all of which require special interaction with the symphony hall in order to operate properly—to make good scientific “music.” Some sensors require us to be moving fast, some slow, some upwind, some downwind, some stopped. Some require our full attention and some operate autonomously. On site, here in the tropical ocean, we are recovering instruments deployed from the ship last year, deploying and recovering a variety of devices that sample only the weeks we are here, and deploying permanently some instruments that become part of the sustained Global Ocean Observing System. From the ship itself we are making a wide variety of detailed measurements of the ocean as we move about. Kyla has listened to everyone’s requirements and delivered a symphonic arrangement that sounds wonderful in our mental rehearsal of the scientific findings. All we have to do now is execute the arrangement in the real world.

SPURS-2 cruise plan.

Overall this SPURS voyage, like others before, seeks a balance in the overall plan of action. Ultimately the goal is to learn how to interpret satellite measurements of surface salinity. This cannot be done without assessing the ocean physics that effect surface salinity and the “forcing” of signals by evaporation and precipitation. Thus, the expedition includes the ways and means for us to assess upper ocean mixing, the role of eddies in stirring the upper ocean, a detailed look at all scales of precipitation, and estimates of evaporation. Of course we cannot measure everything everywhere, so the primary role of the experiments and expeditions are to collect observations that can help us perfect computational models of surface salinity behavior that accurately mimic our satellite observations. Models can deliver estimates of what is happening around the globe and over long stretches of time – scales out of reach from ship observations. Good models lead to better prediction and we certainly need better predictions of ocean behavior for high quality predictions of climate. That kind of impact is what motivates the SPURS team.

The video below shows the view from a small boat as scientists approached a mooring in order to change some batteries. The R/V Revelle is visible in the background. (GoPro video by Raymond Graham/WHOI Mooring Group.)

Finally, as I was drafting the paragraphs above, a sea bird landed on the stern of Revelle. Not just any sea bird but a Peruvian booby. This bird is either blown of course and needs a rest or I need to go back to Booby identification school! I bid you farewell for the day and hope offended birders will tell me how unusual it is to find a Peruvian Booby at 125W, nearly 20 degrees north of the equator.

An off-course Peruvian Booby?

Safety at Sea

October 20th, 2017 by Eric Lindstrom

One of the issues that is never far from one’s thoughts on a ship is preparation for emergencies.  We are a long way from first responders or help of any kind. Therefore, crew and passengers (us scientists) need to be prepared to help ourselves and our mates. This blog is meant to reassure those ashore that your friends and family on Revelle are safety conscious and prepared for emergencies.

Revelle is a very safe and capable platform. It is outfitted with an enormous array of equipment whose sole purpose is to save lives and alert the world if we have any emergency aboard. On Revelle we have weekly drills to rehearse actions in case of the three most likely emergencies.  Those three things are fire, man-over-board, and abandonment of the ship. If we were in some other place in the world a fourth emergency would also be on our rehearsal agenda – piracy! Piracy is not a concern out here in the open Pacific Ocean, but in some areas of the world it would an urgent issue for crew and passenger training.

Life rings at the ready on the aft deck.

During drills we learn where to go for various alarms, what to bring, and what we (passenger scientists) might be expected to do for that particular emergency. In case of fire, the crew is highly trained and the science party would likely be moved out-of-the-way to a safe spot. However, we do need to know how to raise the fire alarm and the different kinds of fire extinguishers available. Obviously initial action can be critical to stopping a small situation from becoming a major crisis. In case of man-over-board, someone must alert the bridge immediately, keep eyes on the person in the water, and begin getting floating objects into the water (kind of trail of breadcrumbs that can lead the ship back to the person). In case we are called to abandon ship, everyone needs to know how to launch a life raft (we have plenty!) and be familiar with the communications equipment available in the rafts.

It is not hard to find a life raft should we need one.

Another issue entirely, and more of a daily concern, is working safely on deck at sea. Oceanography often involves movement of heavy equipment on a platform that may be rocking and rolling and slippery with rain or sea water. Common sense safety requires everyone to be outfitted with a floatation vest and a hard hat during deck operations. It is also common sense to take precautions at night NOT to work alone.

A bin of hard hats ready for a hardworking scientist.

Finally, there is the issue of how our personal safety impacts all aboard. We are in a confined space so illness can spread fast.  That means that we must all pay attention to the public health, such as hand washing and reporting health issues. One must pay careful attention to the hazards one may create in our work spaces. The illness or injury of one person potentially impacts everyone’s projects and the overall expedition. So, overall, there is a increased awareness and devotion to safety when at sea.

I don’t think anyone on the home front should worry about us. All of us are looking out for one another and the crew of Revelle has an awesome commitment to safety and functioning of the ship.

The sunset as seen from the ship on October 18, 2017.

The Commute to Work

October 19th, 2017 by Eric Lindstrom

Going to sea slows one down from the hectic sprint of modern city life and car travel.  We travel slowly (~12 mph) over the vast Pacific Ocean. It is a five-day journey to get to our “office” in the Inter-Tropical Convergence Zone (ITCZ).  The “work day” will change from 8 hours per day to 24 hours per day. There are no weekdays and weekends, only workdays and off-hours. As your blogger, I look into all the projects aboard ship and fill my day with writing, photographing action, and fact-finding for my reporting. I aim to provide a new blog four days-per-week (Tuesday-Friday). If needed I serve on a shift where extra hands are required.

A highlight of our departure from San Diego was being greeted by a large pod of small toothed-whales (porpoise/dolphin family). They seemed as curious of the ship as we were curious of them. We had slowed the ship as we passed the Coronado Island group (off northern Baja, Mexico) to deploy a 42-foot boom off the starboard bow. This is the support structure for Julian Schanze’s “salinity snake” that provides a “clean” intake of surface water outside the wake of the ship.  I imagine the whales had never seen such an operation before!

The 42-foot boom for the salinity snake.

The first two days at sea have been calm and sunny. This has been great for the newbies to get their sea legs. As far as I know no one has suffered severe sea sickness.

In the midst of our five-day commute we stop or slow down for training on occasion. Everyone needs to learn or refresh their knowledge on how instruments are deployed from the ship and safely recovered. This is the time to make sure all gear and personnel are ready for action. I will tell you more about the instruments and projects over the next month. Shipboard life is best when everyone is busy and every project is assisted to full success. During these initial days at sea there is much “cross-training,” you come to sea for one project, but you immediately train to assist on other projects.

Training class at the underway CTD winch.

As we move slowly south to the tropics we also have some small assignments to accomplish on behalf of the oceanographic community.  We will deploy some Argo floats along the 125W meridian. These temperature and salinity profiling devices join a global array of nearly 4000 floats that monitor the upper 2000m of the ocean.

We know our 24/7 work begins when we reach 11N, 125W and begin the process of recovering the NOAA mooring that has been there for the last 13 months.  There are three moorings in the SPURS-2 array and all will be recovered on this voyage. Generally, these moorings become teeming islands of life in the open ocean environment, attracting their own ecosystem of fish.  So, fishing gear will also be at the ready and we can expect tuna and mahi-mahi for dinner the day of a mooring recovery.

Finally, it looks like there will be some Halloween celebration aboard R/V Revelle.  The Captain has brought pumpkins for a carving contest. I hear that some people have costumes at the ready. I am sure some unique nautical and oceanographic twists can be brought to Halloween. We shall see. Never underestimate the imagination of people confined to a ship for five weeks!

Pumpkins at the ready for the Halloween pumpkin carving contest.

Searching for the Bluest

September 20th, 2017 by Joaquín E. Chaves-Cedeño, NASA/SSAI

It doesn’t take a lot of technology to see that the ocean is blue. And when it comes to the blueness of the ocean, it doesn’t get much more blue than where I am. I’m sitting on the research vessel Nathaniel B. Palmerthe largest icebreaker that supports the United States Antarctic Program—on an oceanographic expedition across the South Pacific Ocean, my current home, office, and laboratory. On this voyage, however, the Palmer has broken no ice.

Our Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP) P06 campaign departed Sydney, Australia, on July 3, successfully ending the first leg of this journey on August 16 in Papeete, French Polynesia (Tahiti). This is where our team from NASA Goddard Space Flight Center (Scott Freeman, Michael Novak, and I) joined dozens of other scientists, graduate students, marine technicians, officers and crew members, for the second and final leg that will end in the port of Valparaiso, Chile, on September 30.  The GO-SHIP program is part of the long history of international programs that have criss-crossed the major ocean basins, gathering fundamental hydrographic data that support our ever-growing understanding of the global ocean and its role in regulating the Earth’s climate, and of the physical and chemical processes that determine the distribution and abundance of marine life. This latter topic regarding the ecology of the ocean is what brings our Goddard team along for the ride.

The P06 ship track, for the most part, follows along 32.5° of latitude south. That route places our course just south of the center of the South Pacific Gyre—the largest of the five major oceanic gyres, which form part the global system of ocean circulation. The Gyre—on average—holds the clearest, bluest ocean waters of any other ocean basin. This blueness is the macroscopic expression of its dearth of ocean life. We have seen nary a fish nor other ships since we departed Tahiti—this is not a major shipping route. Oceanic gyres are often called the deserts of the sea. On land, desert landscapes are limited in their capacity to support life by the availability of water. Here, lack of water is not the issue. Water, however, is at least the co-conspirator in keeping life from flourishing. Physics, as it turns out, is what holds the key to this barren waterscape.

This map (above) shows the MODIS chlorophyll climatology with the ship track superimposed.

Due to the physics of fluids on a rotating sphere, such as our planet, the upper ocean currents slowly rotate counterclockwise around the edges of the center of the Gyre–as a proper Southern Hemisphere gyre should—and a fraction of that flow is deflected inward, towards its center. With water flowing towards the center from all directions, literally piling up and bulging the surface of the ocean–albeit, by just a few centimeters across thousands of miles–gravity pushes down on this pile of water. This relentless downward push puts a lock on life. The pioneers of life in the ocean, the tiny microscopic plants, known as phytoplankton, which drift in the currents, and grow on a steady mineral diet of carbon dioxide, nitrogen and phosphorus, and a dash of iron—and expel oxygen gas as a by-product, to the great benefit of life on Earth—must obtain most of their material sustenance from the ocean below. Layers of denser water trap the nitrogen and phosphorus-rich water at depth, keeping it too far down, where not enough light can reach it to spark the engine of photosynthesis that allows plants to grow.

Why are we here and where does NASA come into this story? Since the late 1970s, NASA has pursued—experimentally at first, and now as a sustained program—measuring the color of the oceans from Earth-orbiting satellites as a means to quantify the abundance of microscopic plant life. Microbiology from space, in a way. Formally, though, we call it “ocean color remote sensing.”  Whizzing by at altitudes of several hundred miles, atop of the atmosphere, bound to polar orbits that allow satellites to scan the entire surface of the globe every couple of days, carrying instrument payloads of meticulously engineered spectro-radiometers—cameras capable of measuring the quantity and quality, or color, of the light that reaches its sensors. This is where our work aboard the R/V Palmer comes into the story. The data the satellites beam down from orbit do not directly measure how much plant life there is in the ocean. Satellite instruments give us digital signals that relate to the amount of light that reached their sensors. It is up to us to translate—to calibrate—those signals into meaningful, and accurate, measurements of plant life—or temperature, salinity, sediment load, sea level height, wind and sea surface roughness, or any other of the many environmental or geophysical variables satellite sensors can help us detect at the surface of the ocean. To properly calibrate a satellite sensor and validate its data products, we must obtain field measurements of the highest possible quality. That is what our team from NASA Goddard is here to do.

Around midday, typically the time of the ocean color satellite flying over our location, we perform our measurements and collect samples. We measure the optical properties of the water with our instruments to compare what we see from the R/V Palmer to what the satellites measure from their orbit above Earth’s atmosphere. At the same time that we perform our battery of optical measurements, we also collect phytoplankton samples to estimate their abundance, species composition as well as the concentration of chlorophyll-a, the green pigment common to most photosynthesizing organisms like plants, including phytoplankton. By collecting these two types of measurements at once, light and microscopic plant abundance, we are able to build the mathematical relationships that make the validation of the satellite data products possible.

The optical instrument being lowered into the South Pacific Ocean. Credit: Lena Schulze/FSU

Scott Freeman of NASA works with a R/V Nathaniel Palmer crew member to prepare an instrument for deployment over the side of the ship to collect opHcal measurements. Credit: Lena Schulze/FSU

Mike Novack of NASA studies the optical and biological characteristics of seawater samples in the ship’s laboratory. Credit: Joaquin Chavez/NASA

The waters of the South Pacific Gyre are an ideal location for gathering validation quality data, perhaps one the most desirable to do so, because there are few complicating factors and sources of uncertainty that blur the connection we want to establish between the color of the water and phytoplankton life abundance. Our measurements will extend NASA’s ocean chlorophyll-a dataset to some of the lowest values on Earth.  The water here is blue; in fact, it’s the bluest ocean water on Earth.

This false-color image is a composite, assembled from data acquired by the the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite between September 10-17, 2017. Yellow represents areas with the highest chlorophyll concentrations and purples are the lowest. Credit: Norman Kuring/NASA

Back On Dry Land

October 25th, 2016 by Maria-Jose Viñas

By Alek Petty

A mix of old and new sea ice floating through the northern Beaufort Sea during one of the last days of the cruise that we observed sea ice.

A mix of old and new sea ice floating through the northern Beaufort Sea during one of the last days of the cruise that we observed sea ice.

After 65 Rosette casts, 59 XCTD probes, 61 Bongo tows (nets that collect zooplankton samples), 212 surface water profiles, 40 ocean drifters released, three buoys deployed, one buoy recovered, three deep sea moorings collected and redeployed, eight ice cores collected, and 27 scientists deployed and partially recovered, our expedition around the Beaufort Gyre is finally over! The cruise was a huge success, with virtually all instruments operating successfully. The only downer was the lack of sea ice and our inability to get out onto the ice after Ice Station 1. The lack of ice wasn’t actually a problem for most of the scientists onboard, as they were more focused on measuring the state of the ocean, with the lack of sea ice providing interesting, albeit worrying, context for their measurements compared to previous years.

Final Joint Ocean Ice Study 2016 cruise map (Sept. 22-Oct. 18, 2016)". Courtesy of Chief Scientist Sarah Zimmermann.

Final Joint Ocean Ice Study 2016 cruise map (Sept. 22-Oct. 18, 2016)”. Courtesy of Chief Scientist Sarah Zimmermann.

As I said back in my first blog entry, one of the key objectives of the expedition was to produce an up-to-date assessment of the freshwater content of the Beaufort Gyre. Based on a preliminary analysis of the data collected on this cruise, my colleagues reckon the total freshwater content of the Gyre could be at a record high. A chemical analysis of the ocean surface suggests that sea ice melt contributed around 20 percent of the fresh water mixed up within the surface waters, compared to around 80 percent from Canadian and Russian rivers flowing into the Arctic. The sea ice contribution was thought to be neutral a few decades ago, but the ice is now melting more than it’s growing, as we clearly witnessed, causing an imbalance. The wind circulation is also important in driving the ocean circulation that sucks in fresher surface waters into the Gyre (see an earlier blog of mine for more details).

Why does this all matter? Well, some scientists posited that the Beaufort Gyre oscillates between periods of spinning up and sucking in freshwater, and spinning down and releasing fresh water. A kind of breathing, if you like. The Gyre has been spinning up and sucking in fresh water for a few decades now (2008 saw a big increase) and we keep waiting, with similarly bated breath, for this trend to reverse. If the Gyre does reverse (breathe out), the Arctic Ocean will likely dump a load of fresh water into the Atlantic Ocean (as we think it did in the 1970s), which could cause some big impacts on weather patterns across the Northern Hemisphere. We’re not expecting a scene out of The Day After Tomorrow, but we’re not entirely sure what could happen either.

Hacky sack on the helideck. You can spot me by the bright orange hat.

Hacky sack on the helideck. You can spot me by the bright orange hat.

It will take scientists a while to pour through all the data collected on this cruise and place this year’s findings into context. We spent our last few days compiling reports to summarize and document the data collected (in between games of hacky sack on the helideck). I’ve taken a look at some atmospheric data since I got back, and it appears the Beaufort Sea region was experiencing really warm, maybe even record warm, air temperatures throughout October. The data collected this year could therefore offer us a glimpse of what might be a new normal for the Beaufort Gyre and other regions across the Arctic Ocean.

I wasn’t able to cover all the science that happened on the ship during this blog series, but I hope you got a flavor for some of our primary scientific activities and have a better understanding of why it is we keep coming back to profile the Beaufort Gyre. I’m not sure if I will be out again next year, but I’ll be sure to let you know if I do. Thanks for reading, and do get in touch if you have any questions!

The Joint Ocean Ice Study  is a collaboration between the Department of Fisheries and Oceans Canada (DFO) researchers with colleagues in the USA from Woods Hole Oceanographic Institution (WHOI). The scientists from WHOI lead the Beaufort Gyre Exploration Project,  which maintains the Beaufort Gyre Observing System as part of the Arctic Observing Network. In addition to WHOI and DFO, the 2016 participants (those on board plus those on shore) come from three Japanese, five American, and six Canadian universities and research laboratories. Annual sampling of set oceanographic stations and mooring re-deployments since 2003 aboard the CCGS Louis S St-Laurent have built a time-series of physical and chemical properties of seawater, phytoplankton, zooplankton, and ice observations reaching from shelf waters to 79N across the Beaufort Sea. More information can be found on the Fisheries and Oceans Canada website.