We dropped 17 ocean bottom seismometers today, making 26 in all. The weather is cloudy but bright. There is 2-3 m of swell and this is not a very big ship, so when we were steaming eastwards into the weather there was plenty of water arriving on deck. Later on we turned to the west, which was more comfortable and drier. Scientist cabins are partially below the water-line and my port-hole gets a regular wash.
24th May 2013
Seventy-two OBS will be deployed in a grid of 18 x 4 instruments across the 3-D seismic survey box. Six OBS will be deployed on a profile extending farther west, to try to locate the boundary between continental and oceanic crust.
An OBS is deployed. Photo by Dean Wilson.Gaye Bayrakci, a postdoctoral researcher at the University of Southampton, sent this email update today:
"Yesterday (23/05/2013) the weather was ok. We tested 24 acoustic units first. Then, we deployed 9 OBSs along the regional profile. Before the finish of the day, we tested 24 more acoustic units. Food is good. Thursday is the seaman's day, so we had some cake at 5pm at the coffee break.
"Today (24/05/2013) the weather is darker but its normal for this period of the year in this area. We started at 06am (utm). We just finished the deployment of 8 OBSs on the southernmost profile and reach the eastern end of regional profile. We deployed a 9th OBS here and now we are heading westward along the regional profile."
The international team of scientists aboard the Poseidon includes two GEOMAR geophysicists, two University of Southampton geophysicists, and five OBIC personnel from University of Southampton and Durham University.
The internet connection on board the Poseidon is not good enough at the moment to post to this blog or send photos, so the above photo is from a separate OBS deployment in the Indian Ocean.
Stay tuned for more updates soon!
24th May 2013
One of the goals of Andy Juhl’s and Craig Aumack’s Arctic research is to determine the role of ice algae as a source of nutrition for food webs existing in the water column and at the bottom of the Arctic ocean. During their fieldwork these Lamont-Doherty Earth Observatory scientists are deploying a plankton net, a common tool used by ocean scientists to catch tiny marine plants and animals in the water column, to collect live plankton for identification and examination in the lab. They’re hoping to determine the different kinds of organisms active in this part of the Arctic Ocean and their food web feeding connections, or who’s eating whom by testing the organisms to see if they contain algae in their guts and muscle tissues.
This information is important because it will provide a baseline understanding of the connection between the algal community in the sea ice and the underlying ecosystem, and how it functions. Once this is understood, scientists may be able to better understand and predict changes that could occur in the marine food web as Arctic snow and ice cover changes.
A few days ago we caught the comb jellies in this video near shore at a depth of about four meters. Though comb jellies have the same type of gelatinous body as a jellyfish, they belong to a completely different phylum called ctenophores. Known for being vicious carnivorous predators, ctenophores use rows of comb-like cilia to propel themselves through the top of the water column and prey on smaller organisms, such as zooplankton. Ctenophores are found throughout the world’s oceans, including Arctic waters — quite a few of appeared in the holes we’ve bored into the ice this week.
These two comb jellies were filmed under a microscope in our lab. Each one is just a few millimeters long, though they can grow to be about 10 cm, sometimes larger. You can also see small copepods, a type of zooplankton and favorite food of ctenophores, zipping around the screen. Seeing a lot of ctenophores in the upper water column is a good indicator that they are feeding extensively on copepod larvae, who in turn are feeding on ice algae. This is an example of a few of the connections that make up the foundation of the food web in this fragile, yet biologically productive ecosystem.
On Wednesday Andy and Craig answered responded to questions about their research during a Reddit “Ask Me Anything” session. While the event is over, the session remains on Reddit and we encourage you to check it out to learn about our research and life in Barrow, Alaska.
Our team spent most of Friday on the Arctic sea ice, drilling and sampling ice cores at our main field site. For each core collected, Lamont-Doherty Earth Observatory scientists Andy Juhl and Craig Aumack take a number of different physical, chemical and biological measurements that characterize the ice and the organisms living inside it. Some of these measurements are recorded right away in the field, others will be taken later using pieces of the cores that we bring back to the lab.
Two of the physical measurements Andy and Craig record are the temperature and salinity of the ice. “Temperature is a critical parameter that controls the rate of almost all biological processes in the ice — almost everything happens slower when it’s colder, and parts of the ice can be colder than others. And if you know the temperature and the bulk salinity of the ice you can calculate how much brine volume there is within a given layer in the ice,” Andy explained.
Brine volume is an important measurement because algae live in brine channels in the ice. As ice gets colder, there’s less brine volume within it, meaning there’s less room for algae to grow. Andy and Craig also measure the concentrations of plant nutrients in the ice cores, including nitrate, ammonia, phosphate and silicate – some of the same elements that plants growing on land need. And, as with terrestrial plants, nutrient availability in sea ice is a factor that controls the growth of algae inside the ice.
Other measurements, such as particulate organic carbon (POC) and dissolved organic carbon (DOC), Andy and Craig take in the lab will reveal the amount of carbon, or organic material in the ice. In addition to algae, carbon found in the ice comes in the form of non-living materials, such as bits of organic detritus from the tundra that become trapped in the ice. Finally, samples are collected for microscope work so that project scientists can identify the different types of organisms found throughout the ice.
All of this information varies in any single ice core from the top to the bottom, and based on where it is drilled. By taking consistent measurements from each ice core in different locations, project scientists can develop an in-depth understanding of the dynamics of the Arctic algal ice ecosystem – and how it may be changing.
Our group spent Saturday and Sunday in the lab processing samples from last week and preparing equipment, including mounting a camera system on our small remotely operated vehicle (ROV). We’re heading back onto the ice early Monday morning with the ROV and are looking forward to working in temperatures that may reach 35F.
On Thursday we lowered a camera into an ice borehole to get a look at the underside of the ice. In the following video, you can clearly see the algae living in the bottom of the ice due to their pigments, which they use to harvest light.
These organisms are not frozen into the ice; they’re living creatures that grow and thrive in tiny pockets of brine inside the ice. You might notice in the video that the underside of the ice is not flat, this is probably a reflection of variability in physical conditions in and above the ice, such as snow cover thickness.
While watching this video, Andy Juhl and I discussed how cool it is that there are vibrant communities growing in extreme environments. “One of the lessons that research in polar regions has taught us is that we need to broaden our definition of where life exists and thrives. In the Arctic, we have life growing inside ice, at below freezing temperatures. This means that we know to look in more unusual places for science of life and that’s one of the interesting things we learn by doing this kind of work,” Andy said. “Ice is not necessarily an inhospitable habitat, and on other planets where we see ice, that’s a place where we should probably look for signs of life.”
The second film shows a bit of life on the seafloor. This video was shot near shore where the water depth is about 8 meters, so it’s fairly shallow; water temperature here is -2C. The bottom consists of soft mud and it looks like there are deposits of algae that probably came from the ice on the surface of the bottom (those are the darker areas). There’s a variety of bottom dwelling organisms that live in the mud, such as the isopod that wanders across the mud in this clip. We don’t yet know how large the isopods are or what they eat; scientists on our team are trying to figure out a way to measure an isopod in situ or capture one to examine in the lab.
As our work in Barrow progresses, we’ll continue to post more videos so that you can get a sense of the life that makes up this fascinating ecosystem.
Fieldwork is exciting and inspiring, leading scientists to new ideas, places and observations about how the world works. Spring on Alaska’s North Slope provides an especially productive environment for fieldwork. When the sun never sets, it’s easy to linger in the field and the lab long into the well-lit night.
Our team spent about six hours on the Arctic sea ice Thursday, enjoying blue skies and temperatures in the low teens, while making observations, maintaining sampling sites and taking measurements. Most of our time was spent at two different field sites Andy and Craig established near Point Barrow, a narrow spit of land that’s the northernmost point in the United States. Traveling to these sites involves loading up two sleds with all of the sampling equipment, hitching the sleds to snowmobiles and carefully traversing the sea ice on said snowmobiles, which, I discovered today, is extremely fun.
One of the research questions Andy and Craig are exploring in Barrow is how the amount of snow covering sea ice might affect the diverse species of algae living in and just below the ice. A thin snow cover allows more sunlight to reach the algae; a thicker snow cover creates a darker environment. As in any ecosystem, many different species are competing for light and nutrients. For this study, Andy and Craig want to see how changing one factor in the Arctic sea ice ecosystem – the amount of available light – might allow some organisms to grow better and become more prevalent than others.
Last week Andy and Craig set up an artificial snow gradient at our first field site, where different snow depths cover the ice in a small, isolated area. Ice cores were drilled here on their first day and Andy and Craig will repeat this same exercise later in May. Collecting data over these specific time intervals will enable them to see how snow depth and distribution affect the community of organisms living in the ice. This information will provide an idea of what might happen to the entire ecosystem if more light is introduced via less snow cover in the future.
At the second field site, scientists used an auger to drill a hole in the ice, which is currently about four feet thick. Then a camera was lowered into the hole, with a live feed to a computer so we could see what was happening in the sea directly below us. A thick layer of algae covered the underside of the sea ice and once lowered eight meters to the sea floor, the camera revealed isopods (small crustaceans), jellyfish and a few unrecognizable members of the Arctic marine ecosystem.
“We do the camera work because there’s no substitute for seeing the ecosystem intact. We need to get cores in order to collect samples, but you get a really different impression of the ecosystem with the camera,“ Andy explained.
Later in the afternoon we searched the ice for a sampling station Andy and Craig used last year, but were unable to find it. The area had become covered with huge pressure ridges, large fragments of ice that pile up when sheets of ice collide, which are hard to cross on a snowmobile. At one point fresh polar bear tracks meandered among the ridges, but we never caught sight of the bear who made them.
While I arrived in Barrow, Alaska on Tuesday, Lamont-Doherty Earth Observatory scientists Andy Juhl and Craig Aumack, and graduate student Kyle Kinzler from Arizona State University, got here one week ago. They took a few days to unpack and set up their lab (everything they need to work here must be shipped to Barrow in advance), scout locations for sampling on the ice and ensure that their tools and equipment are working properly before they begin their fieldwork.
Our team alternates days in the lab and days on the ice. The lab space we’re using is a bit north of town at the Barrow Arctic Research Center (BARC), a newly constructed facility where the National Science Foundation leases space for its researchers. Scientists wishing to work in and around Barrow can use BARC as their home base. At the moment the building is fairly quiet as the only other occupants are a group of international graduate students being trained on how to conduct sea ice research.
Today was a lab day, where recently collected samples were processed, experiments performed and preliminary data analyzed. Fieldwork is just the beginning of a research process that can take several years. The majority of the samples and data collected here won’t be examined until scientists are back at their respective institutes, where it can take months or longer to analyze all of their samples and data and then write up the results. But, to ensure that their research is on the right track, a few experiments and analyses are done while in Barrow.
This afternoon I spent time in a zero degree walk-in freezer talking with Craig Aumack, who’s conducting experiments to learn more about the organisms living in Arctic sea ice. Each year, as soon as any light is available, algae start growing in the ice and continue to bloom through the onset of spring and the Arctic’s long summer days. Algae prefer to live in the bottom of the ice, because, like all plants, they need light and nutrients, and these are plentiful at the sea-ice interface.
Craig’s experiments are called settling experiments, and these help him learn what happens to the organic materials and organisms living in the sea ice when they’re released into the ocean. Craig wants to determine the rate at which these particles sink down through the water column; this information reveals whether particles are more likely to be consumed while falling through the water column or once they accumulate on the seafloor. Particles that sink slowly are more likely to be eaten by zooplankton, tiny marine animals, while those that fall to the bottom will be consumed by worms, crustaceans and mollusks.
Settling experiments must be done in a freezer because organisms that call ice home would quickly die if exposed to a 70-degree temperature difference. Though extreme temperatures can also cause humans to become a bit uncomfortable, we’re able to don parkas and puffy jackets to protect us; algae don’t have this luxury. So, Craig replicates the conditions in which ice algae thrive, and bundled up, works in a frigid environment.
Andy Juhl was happy to explain this experiment and their research further, fortunately outside of the freezer. “There’s a whole ecosystem living inside the ice. Ultimately, we want to know what the dynamics of this special ecosystem are and how this is connected to the rest of Arctic ecosystem,” he said.
“We know the Arctic is changing very rapidly in terms of ice cover, duration of ice cover and extent of ice cover. One of the things we need to understand if we’re going to try to predict what will happen to the Arctic in the future is the ice ecosystem and its importance to the functioning of the entire Arctic,” Andy said.
Tomorrow, Thursday, we head out onto the ice to sample. This afternoon I received my land use permit from the Ukpeaġvik Iñupiat Corporation, the organization that owns the land we’ll be working on, and successfully completed my snowmobile training, so I’m officially ready for fieldwork.
Andy Juhl and Craig Aumack, microbiologists from Columbia University’s Lamont-Doherty Earth Observatory, are spending a month in Barrow, Alaska studying algae in and below sea ice, and how our warming climate may impact these important organisms. They’re investigating the factors that control the growth of algae inside of sea ice, how these algal communities are connected to other Arctic marine organisms and what happens to the organic matter that builds up inside sea ice. I’ve joined them to document and tell stories about their research, how it’s done, why and what they’re learning.
Barrow is the northernmost point in the United States and is situated where the Chukchi Sea meets the Beaufort Sea. Throughout the long winter, these waters are covered with a thick layer of ice. This ice is home to many different microscopic algae, which form the base of the polar food web.
During late winter and spring, large communities of these algae flourish, or bloom, inside and on the undersurface of the sea ice. As the ice melts, algae are released into the nutrient rich waters, feeding plankton and higher trophic levels, including fish, whales and seals.
The Arctic is warming faster than any other place on the planet, shortening winter and causing pack ice to thin and break up earlier and earlier each year. How will these changes impact the Arctic marine food web? Answering this question and understanding how the ice algae respond to our warming climate will inform resource managers and policymakers, as well as local residents, of how the larger Arctic marine ecosystem may be impacted.
Andy and Craig hope to learn how our fast-warming climate and the resulting dissipation of sea ice affect the entire marine food web. This knowledge is essential to assessing the value of the ice community in the Arctic and is paramount to predicting ecosystem-wide consequences to rapidly changing Arctic environments.
We’re based at the UMIAQ field station in Barrow, which provides logistics support for NSF-funded scientists conducting research in the area. From Barrow, we’ll travel across the sea ice by snowmobile to nearby Point Barrow, where we’ll establish sampling stations and drill and remove cores of ice. Samples will be analyzed back in the lab to investigate the flux of the algal organisms and organic matter from the sea ice to the water column during the spring melt.
Over the next few weeks we’ll share stories from the ice about our research, the role sea ice algae play in Arctic ecosystems and how that’s changing, and what’s it’s like to live at the top of the planet. And, if we’re lucky, a few pictures of whales and polar bears.
The Lamont IcePod team is a blended mix of engineers and scientists learning from each other through the design and testing of this new instrument. With a range of talents and backgrounds, the project mixes seasoned field workers with those new to field work; experienced instrument developers with those newly learning this end of engineering; and scientists with countless hours spent pouring over Greenland ice sheet data with those exploring the ice sheet for the first time. It is the opportunity for mentoring and development that comes from this mix of early career with experienced personnel that has made the IcePod Instrument Development Project a good fit for its American Recovery and Reinvestment Act funding.
So who makes up the IcePod engineering and science team? As we work through data and examine the products collected in the first part of our field season there is an opportunity to introduce members of the team and the data and instruments they operate.
Chris Bertinato trained as an aerospace engineer before joining the IcePod team. In the air he is the team’s connection to the flight decisions made by the crew. Like the members of the flight crew he dons a headset as soon as aircraft begins its warm up. The headsets are connected into the plane electronics through lengthy cabling that trails behind each set. The cabling necessitates a threading and weaving between the crew as they move about the aircraft, testing and checking equipment and switches. Watching them work one can imagine a class devoted to practicing safe maneuvering about the plane while tethered to the electronics system – something like a Maypole dance!
Chris is a main operator of the equipment rack and has responsibility for the Laser Imaging Detection And Ranging (LIDAR) system part of the optical package in the pod taking constant measurements to find the surface elevation, and the inertial navigation system (INS) used to locate or “georeference” the data. The INS is a critical navigation aid that employs several accelerometers (motion sensors) and gyroscopes (rotations sensors) to continuously calculate the position, orientation, direction and speed of the plane as it moves through space. INS were first developed for rockets, but have become essential instruments for collecting referenced data in an aircraft, since the pitch, roll and yaw of the plane (see drawing) as it moves through the air can make it difficult to correctly locate and orient the data for processing. For those of us used to flying on commercial airliners, movies and music can provide enough of a distraction that we don’t notice the regular rolling of the aircraft as it responds to buffeting by the air around it.
The cylindrical housing for the laser sits snugly in one of the pod bays with the INS sitting atop in the small grey box. The laser focuses down through a clear panel, and scans back and forth in a swath that at 3000 ft. of altitude swings approximately 3000 ft. wide collecting elevation information. The data is then fed through a processor that turns it into elevation data.
The image above shows a swath of laser data over the airbase, and can be used to help explain the instrument. The color in the image shows the reflectance of different surfaces to the laser. You will see three of the LC130 aircraft lined up across the front of the airfield, cleaned from snow and clearly outlined in the data. There are two additional aircraft positioned in the middle of the image that are still surrounded by snow and therefore remain somewhat obscured. Trees, roads and other features in the adjacent area are clearly imaged.
In Greenland Lidar will be used to assist with locating features of interest in the ice sheet. The image above of meltwater channels in Greenland will be important to track during the summer season as these channels can reactivate seasonally, becoming a blue stripe on the otherwise white landscape. These darkened blue sections will absorb more heat energy from the sun due to their altered reflectivity (albedo) encouraging additional surface melt. In an upcoming post we will discuss how the infrared camera carried in the pod will allow us to track the heat energy in the channel both in its current state, and as it begins to melt later in the season.
Lidar will also be used to detect openings in the ice sheet (crevasses). Many of the crevasses are deep yet not wide, making them difficult to detect without the assistance of instruments. Detecting crevasses is important as they pose danger for pilots attempting to land and deliver support to ground crews, can be deadly for overland traverses that are carry scientists and support staff across the ice, and can provide us with critical information on changes in the ice sheet. Lidar data collected in our IcePod flights can be used to help in all of these situations.
For more on the IcePod project: http://www.ldeo.columbia.edu/icepod