10/26/2011

Today is our last day at sea before returning to Dutch Harbor. Along with a few pictures of ice in the McClure Strait that are included with this post, you will see the result of the traditional “shrinking of styrofoam cups”. Scientists and crew decorate cups and then enclose them in a laundry bag that is tied to our seawater sampling apparatus and then lowered into the deep. The colorful cups that you see in the picture – about 20 to 30% of their normal size – were crushed by the pressure of more than one vertical mile of seawater.

    

~ A little chemistry for the curious ~

One of the principal reasons for the joint USF-UAF research on this cruise is that a portion (~25%) of the carbon dioxide (CO₂) added to the atmosphere each year from human activities becomes dissolved in seawater. About 95% of the CO₂ added to the ocean reacts with carbonate (CO₃^2-) to form bicarbonate (HCO₃^– ). This chemical reaction that occurs in the ocean is written as CO₂ + CO₃^2- + H₂O = 2HCO₃^–. In this process, an essential shell-forming component of seawater (CO₃^2-) is consumed and the pH of seawater decreases. This lowering of pH is known as ocean acidification.

Ocean acidification and removal of carbonate from seawater is bad news for organisms that form shells (solid CaCO₃) by combining dissolved calcium (Ca²⁺) and dissolved carbonate (CO₃^2-). When the concentration of CO₃^2- in seawater is decreased, shell formation is impeded. In addition to problems for clams and oysters (both have shells made of CaCO₃), the bad news extends to organisms such as salmon, whose larval forms use organisms made of CaCO₃ as a food source, and even organisms such as crabs and lobsters that use CaCO₃ as a shell hardener.

The ocean acidification process is particularly worrisome in polar regions because cold waters are especially effective at removing carbon dioxide from the atmosphere. This makes Arctic waters particularly rich in CO₂, acidic, and depleted of carbonate. The surface seawater pH for much of our Arctic cruise was 7.7 or lower. In warmer waters, such as those off Florida, a typical pH might be 8.0. This 0.3 difference in the logarithmic pH scale translates to a near doubling of the acid concentration at pH 7.7 compared to pH 8.0.

Studies of changes in ocean chemistry that result from increases in atmospheric carbon dioxide, along with studies of the responses of organisms, are required to interpret and better predict the changes that will be seen in ocean ecosystems in the coming decades and centuries. For more information on ocean acidification, please see the NOAA website: http://pmel.noaa.gov/co2/story/Ocean+Acidification .

Goodbye from the USF team

Bob Byrne

Regina Easley

Matthias Elliott

Sherwood Liu

Jian Ma

10/17/2011

After departing our sampling transect in the McClure Strait we steamed south to sample the Amundsen Gulf. On the morning of 10/18 the sea became covered in “sea smoke”. Air turbulence generated by the ship especially enhanced the effect. Fine snow condensed out of the clear air surrounding the ship and formed a wake of low-lying clouds. At 12:00 the ship’s horn, which announces noon each day, froze open in the icy conditions and had to be cleaned.

 The following day (10/19) we began sampling near the delta of the Mackenzie River, the second largest river in North America. The seawater turned turbid and somewhat green for the first time on the cruise. Three Snowy Owls were seen circling the ship and one member of our owl entourage briefly landed on the upper deck.

After completing our stations along the Mackenzie River delta we proceeded to our final mooring retrieval/deployment site northeast of Point Barrow. We are currently (10/22) analyzing the chemical data that we obtained on the cruise, and are waiting for the weather to allow safe retrieval of the final three moorings. Winds are currently around 35 mph.

Eight Ross’s Gulls were seen today mobbing a Snowy Owl. Ross’s Gulls spend their lives in the Arctic and can occasionally be somewhat colorful due to their diet of carotenoid-containing euphausids and copepods.

The Arctic science being conducted on this research cruise includes deployment and retrieval of moorings devoted to acoustics. Some sounds of the sea included with this post were provided by Josh Jones of the Whale Acoustics Laboratory at Scripps Institution of Oceanography.

Photo taken by Luke DeCicco

Photo taken by Luke DeCicco

The Healy had this extra passenger for about two hours.

 

   

Sounds of Artic Ice

Sounds of Arctic Ice – Part II

Sounds of a Gray Whale

Sounds of a Bearded Seal

North shore of Banks Island at Sunset

Arctic Sunset

Looking for seals south of Prince Patrick Island

Map showing location of Prince Patrick Island, just north of Banks Island

Overnight we headed to our next series of sampling stations. We entered the ice in McClure Strait late in the morning, and saw a few Bearded Seals hauled out on ice floes enjoying the 14 degree temperatures. We began our sampling less than a kilometer north of the high cliffs of Banks Island just as the sun was setting (~2:45pm).

Sunday’s transect across McClure Strait was accompanied by the loud crunching of breaking ice, and the temperature dropped to around 5 degrees Fahrenheit. As we approached Prince Patrick Island, heading north, we encountered a solitary polar bear headed south. The bear seemed indifferent to our presence, while the scientists on board scrambled for a good look at the great white nomad. The transect ended slightly south of latitude 76 degrees north. Shadows of people, cast by the sun at noon here, are fifty to sixty feet long and are growing longer as the year progresses. The entire day looks like a sunset or sunrise, and the reflections of the low sun off myriad patterns of sea ice are, to say the least, enchanting.

Deck operations for sensor deployments

Sensor deployments off the stern of the USCGC Healy

Wednesday (10/12/2011)
was devoted almost entirely to mooring operations. The day included deployment of a pair of USF-UAF sensors for measurement of pH and pCO2. These sensors were placed at a depth of 127 meters, 25 meters above the sea floor. The pH sensor will provide an account of ocean acidity in response to variations in ocean currents, ice formation, respiration and photosynthesis in the area. The pCO2 sensor, in conjunction with salinity and temperature sensors, provides direct measurements of CO2 concentrations at the sensor site.

After the sensors were deployed, we left for a 36 hour steam towards a new transect for collection and analysis of water samples. When we arrived on station Friday morning we had no internet service, with none expected for some time. Our east to west transect along ~74 degrees north began off the west side of Banks Island. The vessel has become cloaked in ice from relatively high seas, nearly 30 knot winds, and temperatures around 20 degrees Fahrenheit. The ice buildup on the bow caused one of our instruments that measures CO2 in the air to shut down.

Tuesday 10/11/2011

Today shipboard operations have largely involved retrieval and deployment of sensor packages that have been located on subsurface moorings for approximately one year. Nothing can be located on the sea surface here because it would be destroyed by winter ice. During the previous two days, the sea state was too high for mooring recovery operations. Such operations can be difficult because they involve small boat operations to attach retrieval lines to the array of floats, lines and instruments. When mooring operations are postponed, and the sea state is not too high, work on collection and analysis of water samples continues – sometimes at a rate, and for a duration of time, that creates substantial sleep deprivation. Such has been the case for the previous few days. The USF team has found itself working, on average, 15-hour work days with the greatest amount of sampling occurring throughout the night.

Snow has begun to accumulate on the decks of the Healy. This makes travel fore and aft on weather decks somewhat more hazardous. The scientists’ quarters are approximately sixty yards forward of, and two decks above, the science laboratory. Travel to and from the staterooms to the main lab involves a choice between the outdoor route, through wind and snow, and the inner route, which involves opening and closing five water tight hatches. The outer route is generally faster, and is the near equivalent of a cup of coffee.

Luke DeCicco took this photograph as we passed this walrus family in the Chukchi Sea.

Sun angles are always low this time of year in the Arctic.

Buoy Recovery Operations.

Jian, Sherwood and Regina draw samples for pH, carbonate, total inorganic carbon and alkalinity.

Taken by our US Fish and Wildlife Bird Observer, Luke DeCicco. Snowy Owls are a nomadic species with a range on the order of a thousand miles. They often venture a hundred miles or more onto the arctic ice in search of prey.

We've been sampling vertical profiles in the water column along a several transects near point barrow.

Nearly all of Friday night and Saturday morning was spent collecting and analyzing water samples. The afternoon of Saturday was filled with operations involving retrieval and deployment of moorings. The first of two moorings was acoustically released but never rose to the surface. If it cannot be retrieved by another vessel at a later date, this will amount to the loss of not only expensive equipment but also a year-long acoustic record of whale activities, the sounds of ice formation and movement, and other sounds of the arctic including those made by seals and fish.

Dark eyed Junco's are typicaly a temperate arboreal species. This one has flown far out of its normal range and has taken refuge on our ship.

We began a new transect for collection of water samples in the early morning darkness with the bright lights of Barrow, the northernmost city in the United States, on the horizon to the south. As our line of sampling stations took us north, the bright city lights faded and disappeared. Dawn brought a lighter shade of gray clouds than the previous two days, and afternoon bought snow squalls.

On Friday night, Jessica Cross, one of the two University of Alaska Fairbanks (UAF) students of Dr. Jeremy Mathis, was seen wearing an Oceanography Camp for Girls (USF) tee shirt. It turns out that as a middle school student in 1998, Jessica graduated from our College of Marine Science summer oceanography camp program. It is amazing that Jessica was one of the enthusiastic young “campers” who I saw, and heard, outside my office nearly every summer day so many years ago. Dr. Teresa Greely, who runs the program, can be proud of this graduate, now in her fourth year of Doctoral studies at UAF.

10/06/2011

Thursday was filled with analyses of seawater for the USF group. Water depths have generally been less than 60 meters, and water temperatures near the bottom are below minus 1 degree Celsius. Some of the ship’s rails have a rim of ice at night and thin accumulations of snow occasionally appearing in places on the deck. Since we are north of 71N, the sun is never high in the sky, accentuating the slate-greyness of the low cloud layer. We are often in sight of land, and there have been sightings of Walrus and even a snowy owl. The aurora was once again spectacular in the early morning.

10/5/2011

Wednesday night was dark with a good display of the Aurora Borealis around 3am. Clouds moved in before dawn and sunrise changed the sky from black to gray. The Healy recovered a meteorological buoy in the afternoon, and afterward the ship’s seawater sampling system collected water samples for practice measurements prior to our first real hydrocast scheduled for shortly after midnight the following day.