One afternoon a young adult female polar bear wandered by the ship. She appeared out of the blowing snow and walked past the stern, fairly close to the ship. An hour later she reappeared and approached the ship, walking up the fantail until she was directly below the railing. Scientists and personnel from the ship were pressed at the railing above, and she just seemed to be curious, sniffing the wind and looking back at us, occasionally pawing the broken ice at the ship’s waterline.

This young adult female bear walked past the ship, eventually coming right up to the ship.

The polar bear, standing just below us at the stern of the ship.

The railing of the fantail where folks are standing is about 5 meters, 15 feet, above the ice where the bear was standing, at the aft end of the ship, the fantail. It was a wonderful chance for people to see this bear up close.

The wind finally dropped below 20 knots for a day and we flew for the bear – only to encounter heavy fog that prevented us from finding her. We located another bear that was a lower priority and we successfully captured her, yielding good data. The next day the fog dissipated and we flew for our priority bear again, but she had moved over 30 miles and we could not locate her until we received a satellite transmission at the end of the day. We remained in the area because this bear was one of the two top priority recaptures remaining, and we successfully located her twice, but both times she was traveling in large areas of broken ice which were unsafe for captures. The temperatures remained warm throughout this period, rarely dropping below 25 degrees; the water temperature remained warm as well, and sea ice simply was not forming very fast.

Poor ice near one of our priority bears.

This is a frustrating aspect of field work: success relies heavily on weather, and the bad luck of encountering stretches of poor weather can put an entire field season on hold. The only thing that can be done is planning. We planned a long field season to provide multiple opportunities to recapture each bear, and we planned on capturing secondary target bears as necessary. Thus, even though strong winds and fog really reduced our flight opportunities and poor ice reduced our capture opportunities, we had successful recaptures of target bears and we were able to process new bears as well.

The poor ice conditions we have encountered are remarkable. Air and water temperatures remained very warm throughout October, slowing the formation of new ice as winter begins. The current distribution of sea ice in the Beaufort is much more typical of late summer than early winter – we have not had to break heavy ice at all in the last 10 days. It is inaccurate to state that this warm October has been caused by climate change; climate refers to long-term patterns of average conditions, not day-to-day weather. Even in a world with an enhanced greenhouse gas effect, some autumns will be colder than normal and others will be warmer than normal. However, climate change is changing what is considered “normal.” As the earth’s climate warms, particularly in the Arctic, the type of weather we are experiencing may become common.

Graph from National Snow and Ice Data Center. Extent of sea ice over the entire Arctic is currently low compared to the 1979-2000 average, in fact, it is nearly as low as the same date in 2007, when the extent fell to a record low.

Today we disembarked from the ship, using helicopters to ferry people and luggage back into Barrow. Although the trip ended on a frustrating note, overall, it was a very exciting success. Every piece of data we gathered is unique – almost nothing is known about polar bears during this time of year, particularly bears out here on the pack ice far out at sea. I cannot wait to return to Laramie and receive data from our shore-based capture crew, which recaptured bears on the coast during the last several weeks. Before any in-depth analyses, it will be informative simply to compare data sets from the bears on ice to the bears on the coast, to see if differences are striking.

It took several hours to sort, weigh, and tag all of the personal luggage going out to the ship. It took several more hours to ferry the personnel by helicopter, and the luggage by landing craft. I stayed with the luggage to help keep it organized and insure that no pieces were mixed in with the outgoing science party. The day was windy with several snow squalls, and the landing craft rolled and crashed over large swells during the 20 minute ride out – it was a lot of fun.

Wearing a cold-water survival suit, waiting on the beach for the landing craft launched from the icebreaker.

It was surreal to pull up next to the icebreaker (399 feet long) in the launching craft (perhaps 35 feet long). Our little boat was getting pummeled by the waves – I had to brace myself against the handrail during the entire ride – and spray from smashing into waves had been washing over the open deck. However, as we pulled into the leeward side of the icebreaker, the immense ship sheltered us from the wind. I’m not sure, but the icebreaker must be at least 6 stories tall; it was like pulling the boat up to the base of an immense cliff. The Coast Guard personnel threw heavy lines up to the ship and secured the boat then we clambered up a rope ladder and onto deck. A different crew member immediately helped us gather our luggage, and showed us to our rooms.

The rest of the day was spent organizing (no surprise there). We hurriedly unpacked our own gear into our rooms then began the long process of finding all of the project gear in the cargo hold and bringing it up to the lab spaces. Somehow, in the narrow hallways and cramped stairs (more like ladders) of the ship, everyone managed to maneuver their equipment into the labs.

We left the Barrow area and cruised west then north, to avoid the waters near Barrow during whaling season. We then traveled east then north again; by this morning we were passing – and occasionally crushing – large pieces of floating ice. We have not cruised through any solid ice yet, only fields of floating ice. This morning I ducked out onto a side deck before breakfast to take this picture of dawn. Temperatures have been hovering around 30 degrees (Fahrenheit).

This morning we launched for captures for the first time. As we flew to the north, trying to radio track some bears for recaptures, I looked back and saw the icebreaker sitting in the trail of open water it had created. The ship that looked awesomely large from the water looked small from above. The deck from which we launched is visible at the stern. Unfortunately, because we did not encounter large areas of solid pack ice as we flew there were no safe places to perform captures. After short flights, we returned to the ship. We are currently underway and we plan to cruise north for about two days, towards different collared bears, in hopes of working on better sea ice.

The pace of work has continued to be frenetic – our lab is finally up and running, and all of the instruments seem to have made their journey intact. All of the capture equipment was in place for the flight today, and hopefully we will use it soon. Tonight is chance to catch up on some rest.

Open water is appearing as the sea ice breaks up and begins melting. I took this photo from our helicopter yesterday, about twenty miles north of the Arctic coastline.

Polar bears mate in the spring. Females undergo delayed implantation; the fertilized egg does not implant into the wall of the uterus and begin development until autumn. Delayed implantation is unusual, but a surprisingly large number of mammal species do it. Despite much research, there is no consensus on the function of delayed implantation. Pregnant female polar bears dig dens in snow (and in some parts of the Arctic, into earth) in the fall then spend the winter in the den. They give birth to young sometime in December-January then the entire family emerges from the den in the spring.

This little bear is known as a C.O.Y. for “cub of the year.” Most of the COYs we have caught weigh around thirty pounds, and are still nursing. Usually, they will remain with their mothers until they are just over 2 years old, when they become independent. At this capture we have anesthetized both the mother and, with a very light dose, the cub; that is why the tip of his tongue is sticking out.

This is a one year-old that is still with its mother; it weighs 220 lbs. Around this time next year, it should become independent.

Research published in 2007 found that the subunit of polar bears in western Hudson Bay was a declining population. There are many mechanisms that can lead to population decline; in western Hudson Bay, survival of very young and very old polar bears has fallen over about the last 20 years, in concert with an advancing date of sea ice breakup in the spring. It is unknown exactly how sea ice decline affects polar bears, although it is likely that poorer ice conditions reduces the ability of bears to hunt. A goal of our project is to track changes in the physiology of polar bears during the summer, with particular attention to how changes may be affected by declining sea ice. This will help us understand why the western Hudson Bay population is declining, and how other subunits may be affected.

As the warm weather continues, we also have clear skies and good visibility, so we have been getting out for a lot of captures. Very long days – typically we fly out in the morning, perform captures throughout the day, then finish up lab work around midnight – but we are getting a lot of great data.

Of what I speak is a seabird colony existing where the marine ecosystem has not been subject to wide-scale pollution from agricultural and civic runoff, fish depletion, introductions of alien species, harmful plankton blooms (“red tides”) and lots of other things that currently ravage most marine ecosystems of the “civilized” world. I speak of the Ross Sea, the last ocean on Earth where seabirds are capable of being too successful in their breeding. Hmmmm, yes, you heard me right. That is a statement that should give you pause for contemplation, and refers to a concept foreign to most marine ecologists. And what could I possibly mean by this? How can a colony of seabirds ever be too successful?

If you’ve been following my previous dispatches to Ice Stories for this recent Antarctic summer, one was called “Royds Tranquility” and another was “Beaufort Chaos”. In those I reported on the contrast between the Royds penguin colony (one “city” in this story, 2000 penguin pairs) and the more populous colony at Beaufort Island, the other city (60,000 pairs). The Royds colony was very quiet but at the time miserably failing owing to the 70 km walks that most parents were making to find the ocean and food…and 70 km back. The extent of fast ice was very unusual owing to very calm winds last winter and spring. Other than birds attempting to remain resolute on their nests, no others were present. Deserted eggs were everywhere, as more and more adult penguins giving up and going off to feed, their mates choosing not to return.

At Beaufort Island, where the ocean was at the penguins’ doorstep, just a short skip away, penguins were coming and going in multitudes, and because many nested in suboptimal habitat– being forced to do so because the good spaces had all been taken– some were losing their eggs too. But there were huge numbers of eggs still under other parents, being warmly incubated. In addition, due to a short journey from wintering areas just before nesting, all colonies, Royds included, began the season with their respective breeding populations at maximum, i.e. above normal. “Everybody”, it seems, attempted to nest! [If you’ve not read the earlier dispatches, perhaps do so before proceeding further in this one.]

About 40 km to the east of Beaufort, the colony at Cape Crozier was in a similar state to Beaufort: maximum proportion of a large colony, twice the size of even Beaufort (150,000 pairs), attempting to breed. Well, we could not follow up at Beaufort (couldn’t get there at the end of the season) but did have the opportunity in regard to Crozier. I think the stories for both Beaufort and Crozier were pretty much the same, although, being smaller, likely Beaufort didn’t have quite the problem experienced at Crozier.

At all our penguin colonies, there are the “super breeders” who almost always produce young– despite conditions– and then there are the “other” penguins. Mainly the super breeders have learned, through experience, about the vagaries of factors that penguins need to know about. This involves just 25% of the population, or thereabouts; the remainder of penguins almost always fail unless conditions are really easy. This season, the super breeders came front and center at Royds. Not only did they successfully hatch their eggs (unlike the klutzes) but also raised the maximum of two chicks. Therefore, even though 75% of nests failed, the total average chick production of the colony was 0.6 chicks per nest, which isn’t all that bad, given that in good years, an average 0.9 chicks are produced among all nests in which eggs are laid.

What these super breeders had figured out was that they could feed through narrow cracks in the ice and not walk all the way to the open ocean. Then, the ice opened into a polynya [patch of open water in the ice] off Royds, as I described in the “Minke Friends” dispatch. From then on, foraging was easy and the Royds chicks ballooned to become heavier than even last season, averaging around 3800 grams by the time they were 6-7 weeks old and within a week or so of fledging. That’s BIG for an Adélie penguin chick! As is the usual, the Royds chicks didn’t form crèches [groups of penguin chicks] because almost all the time, at least one parent was present to protect them.

Below are two images of Royds, taken on 17 January 2009, showing all the adults present. The reason that there are an equal number or more chicks than adults is because most chicks had a sibling…so two chicks for every successful nest.

Chicks and adults at Royds.

Penguin adults and chicks at Cape Royds, Antarctica.

So now, what about the other penguin city, the one at Crozier (standing in for Beaufort in this tale)? At Crozier, not only did a maximum number of birds attempt to breed, but almost all successfully hatched their eggs. This was because initially finding food was easy, as long as a parent only had its own mouth to feed. Not long after peak hatching, though, the parents began to make longer and longer foraging trips as they depleted food nearby. Of course these seabirds had help from whales and fish in this consumption, unlike the case for any other place in the World Ocean.

Chicks at first did ok, but once they reached the age of maximum growth rate, around 3 weeks of age, troubles began for Crozier. Eventually, parents’ trips reached three days long and less food was returned as some was digested on the trip back (these penguins hold the food in their stomachs, and then regurgitate it to their chicks — see previous dispatch — and once that cold wad begins to heat up in the parents’ stomach, it begins to digest, a common occurrence when the trip back to the colony is more than a day long). Well, basically the chicks at Crozier, though reaching appropriate size (height) for their age, became way under weight. At week 7 they were more than 1 kilogram (1000 g) lighter than Royds birds, and their feather development was halted. In fact, average weight was lower than we’d ever measured it at Crozier. Many chicks began to die of starvation. There were just way too many of them to be fed with the result that almost all were under-fed. In fact, breeding “success” at Crozier was 1.0 chicks crèched per original nest (it’s usually no better than 0.9). Wow! That’s a lot of chicks when you consider there were 150,000 nests to begin with.

Looking to the immediate future, it would seem that the chances for eventual survival of the Crozier chicks is close to zero, quite in contrast to the fat, vigorous but many fewer chicks at Royds. The Royds chicks should have a great chance for survival.

Below are images from Cape Crozier taken on 20 January. The contrast with Royds is dramatic, as almost no adults are present, even though the chicks are just a few days older than those shown in the images above from Royds. Sad.

Cape Crozier chicks with few adults in sight.

Cape Crozier chicks with few adults in sight.

Here you can see lots of chick carcasses. These chicks, unfortunately, have died of starvation. Also sad.

Crozier chicks and carcasses.

So, this is all pretty amazing, but we had to go through the entire season to see how things played out, and flip-flopped Royds vs Crozier. In the last several seasons (2001-2005), we witnessed somewhat similar events at Crozier, but chalked it up to effects of the big icebergs that were present then. The icebergs occupied a large portion of the Crozier colony’s foraging area.

Those icebergs have been gone now for two seasons. So, we have to consider other ideas to explain what is going on now. Perhaps, it seems, Cape Crozier has grown too large!! This rarely could happen to a seabird colony elsewhere in the world. Mostly this is so, because the population is kept low by pollution, toxic die-offs, invasions of feral animals or other type events; or breeding success is low owing to difficulty in finding food early in the season (over-fishing). In some warmer-water colonies of seabirds, where the environment allows the population to be present year round, a portion of large populations may just hang out in waters nearby and not participate in breeding. That doesn’t seem to be an option for migratory seabirds nor for seabirds that live in extreme environments, in both cases like is the case for Adélie penguins.

Well, ok, it was a very “educational” season for us, as are many. To complete our education, though, we have to be present in 4-5 seasons hence to tally the winners and losers among the penguin cities. That’s because young Adélie penguins spend their first years at sea and don’t visit the colonies.

For this season we are done, and here is what our camp at Cape Royds now will look like through the winter darkness. (See dispatch, “So, You Want to Be a Penguin Researcher?” for a view of the camp all set up.) In a couple of months you’ll need a flashlight to see this, our camp in a small box….well, a slightly large one.

Our camp.

The reason we go to Beaufort is that it appears to be the true “penguin pump” in this cluster of colonies in the southern Ross Sea. We want to confirm this. The colony at Cape Crozier produces lots of chicks, like Beaufort, but it has a huge area for expansion, if the penguins are up to that. Mostly they are not, because more and more penguins in one area leads to more competition for food in nearby waters. To avoid that, young Crozier penguins might want to find a territory elsewhere, or not, like at Cape Bird.

The Beaufort colony also regularly produces a lot of chicks, but until recently there was no room for the young prebreeders that result from that to find a spot, except in very poor habitat (see below). That’s why young Crozier birds didn’t want to move there either. The Beaufort breeding area has been hemmed in by vertical cliffs behind, and open ocean the other way. Penguins would be everywhere where they possibly could be, wall-to-wall so to speak. Penguins that didn’t want to tussle for a spot definitely would show up elsewhere like Cape Royds: lots of space there and no competition for food. We know this because we’ve been making the icebreaker trips almost every year since 1996 in order to band a bunch of chicks at Beaufort. In later years, we see these banded birds at Beaufort but in disproportionate numbers we see them at the other colonies, too…until recently.

Beaufort, 2001.

Here’s a shot of Beaufort from the air taken in 2001; west is towards the background. You can see the ‘shelf’ of gravel on which the colony nestles, hemmed in by precipitous cliffs in the back, snow fields to the west, and the ocean. Penguins are everywhere that there is level ground and no ice (there are about 60,000 nests crammed into this area). The west end of the colony is hemmed in by ice fields (see next photo).

Yes, disproportionate numbers of penguins raised at Beaufort have been going elsewhere until a few years ago when global climate change began to kick in around here. Then, with slightly warmer temperatures the snow and ice fields on Beaufort began to rapidly retreat [sound familiar? Hey, I drove up to see Glacier National Park this past summer to see the glaciers before they are gone….maybe by 2015 they say.] This warming caused the ice to retreat at Beaufort also, thus exposing lots of terrain with lots of small pebbles, ideal for nests.

A new breeding area at Beaufort.

Here is a picture of penguins setting up territories at the west periphery of the colony that until recently, 2001 (see aerial Beaufort photo) was covered (probably for the last 20,000 years) by snow and ice. These penguins were not here in 2001. So, you see, that bad-ee, Global Climate Change, can be “good” sometimes!

Well, there are so many penguins trying to find a nest at Beaufort, and so little space and not enough rocks, that, actually, Global Climate Change is not happening fast enough!! As a result, many penguins are nesting in suboptimal habitat and more than likely they will lose their nests and its eggs. This will force them to be more prudent next season. Either they will set up nests at the west end of Beaufort (see photo above)…the most likely….or many will seek out places like Cape Royds, where lots of stones are to be had along with lots of space (and usually open water; see next blog dispatch).

With stones in short supply, some penguins turn to nesting in guano (penguin poop).

These penguins are nesting in scoops in the guano with almost no stones. All of the stones have been used up by other penguins! More than likely their eggs will roll out of the nest and, in fact, on our next visit following this one, we found eggs EVERYWHERE.

With an insufficient number of rocks holding a nest together, penguins’ eggs roll out and are lost.

There are well over 30 whole eggs in this picture that have rolled out of nests. There simply were not enough rocks for the penguins to build the protective “basket” to hold them.

Still lots of nests had eggs but lots had rolled away– so many that the skuas had too many to eat! The other thing that happens when a penguin has a scoop but no stones, is that it fills up with water. That’s bad for eggs and chicks.

Penguins with drowned nests.

Here are penguins who built nests, and laid eggs, in a depression that initially was dry but now is filled with melt water. There was no room for them on high ground. Yes, there are eggs underneath these birds!! This is a demonstration of how staunch penguins are, in spite of adversity. They won’t give up until the conditions become impossible. These are impossible conditions, and yes, these penguins gave up!

Ill-fated nests.

Here are a bunch of penguins that have built their nests on a nice sandy beach (above). How idyllic! It’s the kind of place that people would hang out; all we need are some palm trees. However, when all that ice in the background eventually melts later in the summer, then the sea is going to come pouring in, waves crashing, to wash the penguins’ feet, but also their eggs and chicks, too. These penguins, too, next season will be looking elsewhere for making a nest!

So you see, and I know you’ve been told this before, Nature works in strange ways. It takes some adversity to convince penguins, and people, to alter their behavior…that is, to stay in higher or safer ground!!!! This is going to be the same for people beginning very soon, as global climate change REALLY gets going. I hear that insurance companies no longer are insuring houses on the US Gulf Coast, owing to increasing numbers of hurricanes and rising sea level. See, if the insurance companies can’t afford this, neither can the rest of us. Where are all those Floridians going to be living? In Georgia, I guess. Penguin Insurance Companies, to stay in business, would not insure these penguins’ homes shown above. (Penguins don’t get government bailouts for bad decisions.)

Every season, we band a lot of chicks at each colony, and in later seasons spend a huge amount of time looking for them when they come back as pre-breeders (teenagers) and then adults. The numbered metal bands are placed around their left wing and this will identify each bird, as well as the year the bird was born and its natal (birth) colony. Once a banded bird begins to breed (its mate or itself laid an egg), we mark its nest with a plastic tag and nail driven into the permafrost. Then we keep track discovering what happens to each banded bird during the course of its lifetime, at least here at the colonies.

Wing Band. Numbered metal bands are attached to the birds when they are chicks. It identifies which colony the bird was born in and what year.

The banding process takes place at the end of the breeding season just before the chicks do their final molt and head out to sea for the winter: 400 chicks each at Royds and Beaufort, 1000 each at Bird and Crozier, each year. We’ve been doing this since 1996 full-scale, with a few banded in 1994 and 1995. So, in total, more than 33,600 chicks banded to date. This banded “sample” of the colony population will serve as an indicator for the movements and survival rate for each colony.

Some of the things we have learned so far are: Adélie penguins do not always return to the colony of their birth and will move from one colony to another to breed and raise their chicks. This is why we call this complex of colonies a “metapopulation”…no colony is independent of the others. What causes penguins to relocate is mainly due to, as we said, access to the ocean, but also the difficulty of finding food or nest stones where there are a lot of penguins. Thus as colonies grow, and resources become harder to come by, penguins are encouraged to move to smaller colonies….just like people!

Beaufort Island Adélie Penguin colony. These grounded icebergs have been here for several years. They are about 1 km off shore and dwarf everything in the area.

Here is the Ross Sea and the coast of Victoria Land in a NASA image taken last week (below). The red stars show the members of the colony cluster that we are investigating. The blue stars show the other Ross Sea Adélie Penguin colonies.

Penguin colonies in the Ross Sea. Photo courtesy of NASA.

Only the Terra Nova Bay (2 colonies) and Cape Hallet colonies have been thoroughly search for our banded birds, thanks to colleagues in the Italian Antarctic Program (Silvia Olmastroni and friends) and New Zealand Antarctic Program (BJ Karl and friends), who camped at each for several weeks. They found one of our banded birds at each of these three colonies. So, now we know that birds within our metapopulation exchange readily among themselves, but also we know that a few, but not many, intrepid penguins go much farther afield in search of a breeding spot. Tourists with sharp eyes have also noted single banded birds at Franklin Island and at Coulman Island.

At Cape Royds, where we are camped, there are about 2000 nests, so looking for bands takes one person about an hour to complete. However at one of the other colonies in our group, Beaufort Island, there are 60,000 nests and the other day it took four of us four hours to search, and doing so without pause. In fact, we were walking more rapidly in search for bands than is our norm.

In past years there has been open water between Cape Royds and Beaufort so helicopter transport was not possible and band searching could not occur at Beaufort. However, this year the ice is thick so helo transport is possible. From Cape Royds it is a 30 minute helicopter ride to the Island and on this day we stopped to pick up help from Cape Bird: Katie Dugger (co-PI on the project) and Len Doel (volunteer from NZ). Unlike the birds at Cape Royds, the Beaufort Island birds walk less than one mile to open ocean. Why then do the Cape Royds birds make the 50 mile trip when they could nest at Beaufort? We’ve given some hints to the answer, but this is a question for another day.

To establish a breeding colony, Adélie Penguins need ice-free land with a supply of small rocks to build their nest. Beaufort Island has a large beach area with plenty of rocks, but also always easy access to the ocean. So this colony is larger than Royds.

Beaufort Island Colony. A large, ice-free beach with lots of small rocks. The brown areas are where the penguins are. This colony has about 60,000 nests.

Searching for bands requires binoculars and a good eye as you walk along the nesting areas. When we found a banded bird at Beaufort we recorded its number and whether it is on a nest, alone or paired and if the nest has eggs we record the location using a GPS.

Searching for bands. It takes patience and good binoculars to find the banded birds in these large groups.

Color anomalies are rare in penguins, but with a colony this size there is bound to be one, today we found a blond penguin. Its color does not seem to affect its ability to survive.

Blonde Adélie Penguin. A rare color anomaly.

A good days work; about 80 banded or known age birds were identified representing all four colonies of birth, Cape Crozier, Cape Royds, Cape Bird and of course Beaufort Island. The vast majority of banded birds were banded as chicks at Beaufort. We found 5 that were hatched and banded at Cape Royds. In another 7-10 days we will visit Beaufort Island again, because by then all the females will have replaced their mates on the nests. Thus, we’ll probably find another 80 banded birds who were not there a few days ago.

End of day. Searching for bands is hard work in the cold and wind. We are ready to head home.

Kate pictured with large mooring float.

Recovering a mooring of any significant size essentially amounts to getting it to the surface and picking it up with a ship using a crane. Recall that one of the key items contained on the mooring is the acoustic release. The release is essentially a chain link that opens up when it receives a particular acoustic waveform placed into the water.

An acoustic release with integrated beacon.

Many, such as the one Kate is using, also send out a beacon or “ping” when acoustically interrogated. So, to recover a mooring, one steers the ship to the GPS location closest to where the mooring was deployed, places the appropriate set of tones in the water which will induce the release to start sending beacon tones and release the mooring from the anchor, and then home in on the mooring’s location using the beacon. At this point, the mooring can be reached at the surface, and only the anchor remains at the bottom.

To physically perform the recovery on a big ship such as Healy, a rigid inflatable boat (RIB) is dispatched from the recovering ship to find the top float(s). Of course, if the top float(s) ascended under a blanket of sea ice, there are more details to handle, but we didn’t have to deal with this particular problem on this cruise. We avoided it by electing not to recover a particular mooring on the first day and coming back later to recover it (when the ice had moved on).

Rigid inflatable boat (RIB) used to recover moorings.

The small boat will locate the mooring by looking for the float(s). Floats are typically painted in colors or contained within painted containers that are relatively easy to see, even in poor weather conditions (e.g., optic yellow or orange). One of the more common float arrangements is to strap together a collection of glass spheres each of which provides a certain amount of buoyancy and can resist the high pressures of submergence at depth. Such spheres can also be used to house instruments. Floats for less extreme depths, made of plastic or foam materials, can be used for applications involving less pressure (foam compresses at high pressure and loses its buoyancy; glass does not). In some applications the float is allowed to bob around on the water surface (called a “surface expression”), but in cold areas such as the arctic this can be a problem because floating ice can damage a float or, worse, carry off the entire mooring.

Once the small boat operators get a hold of the recovery line attached to the float, they maneuver to the stern of the recovering ship and connect the recovery line to the ship’s crane line. At this point, the small boat gets out of the way so the ship’s mooring crew on deck can recover the mooring. This is accomplished by winching in the line and moving the A-frame, which is a large metal inverted-U-shaped hoist attached to the ship. It is operated by hydraulic lifters and is used to position moorings or other equipment beyond the stern of the ship over the water.

Crane and A-frame used to hoist mooring (floats and audio recorder are visible).

Deploying a mooring, or re-deploying a mooring, involves placing the mooring into the water top-to-bottom (there are other ways, but all the moorings deployed on this cruise were done top-to-bottom), with the recovery line first and anchor last.

Mooring with acoustic release, audio recorder, CTD and float ready for deployment; the recovery line and its floats are already in the water.

If the mooring is sufficiently small (like Kate’s) it is possible to lay the entire mooring out on deck ahead of time.

Kate awaits the ship to be positioned for the next deployment. The full mooring is visible on deck.

First, the top float(s) are placed in the water, then the instrument(s), then any additional floats and finally the anchor. The anchor is placed in the water by careful use of the ship’s crane. It may be partially lowered into the water and released at just the right time so as to land on the ocean floor at the desired location. After the anchor is released, it sinks to the bottom pulling the rest of the mooring along with it. It is thus possible to see the primary float(s) rapidly approaching the stern of the ship until they are pulled below the surface.

Anchor weights are deployed by the winch. John holds a line that when pulled releases the weights from the crane.

Although the recovery and deployment of moorings may seem conceptually simple, there are many details to get just right. Errors in mooring design or deployment execution could mean a costly waste of ship time, a loss of data or equipment, or possible injury to the scientists or crew. This is true of most heavy work on ships, but is exacerbated when working in the Arctic due to the hostile conditions. For this set of scientists and crew, mooring recovery and deployment is conducted by the Woods Hole Oceanographic Institution’s Mooring Operations Engineering and Field Support Group, led here by John Kemp, a legend in the “mooring community.”

Emblem of WHOI Mooring Ops.

John Kemp, WHOI’s expert at mooring design/recovery/deployment.

Although I personally lack the level of sea experience this crew has by many orders of magnitude, I have been around ships and small boats for most of my life, and I can appreciate a virtuoso at getting work done at sea, and John is definitely one.

(Thanks to Dale Chayes (LDEO) and Kate Stafford (APL) for helpful comments on this article).

Placing a Mooring

Kate’s moorings, like most others, are constructed to be placed on the sea floor at a particular location and depth. Locating nearly anything on the surface of the Earth has become much easier with the widespread use of the Global Positioning System (GPS) and its relatives (assisted GPS, differential GPS, carrier-phase GPS, Real-Time Kinematic (RTK) GPS, etc). Knowing the depth (and associated bottom contours) at a point in the ocean is less straightforward, yet these details are important for designing and manufacturing moorings, as these details affect certain aspects of a mooring’s design such as the amount and strength of cable required, the weight of the anchor to be used, the amount of buoyance required, etc.

Ocean depths are typically measured with an echosounder (see below) and then recorded on bathymetric maps. Contour lines of the same depth are called isobaths. The map below indicates our ship’s cruise track, mooring deployment/recovery locations, geopolitical data, plus a number of isobaths (black lines) and bathymetric data (salmon-colored tracks).

Cruise track, made available to the science party underway, had a number of optional overlays. This shows the track, geopolitical map, bathymetric data, and mooring deployments/recoveries.

The bathymetric data used to create such maps are measured using either airborne platforms (e.g. satellites) or ships’ sonar systems. Healy has a multibeam sonar system. Using multiple sound beams allows the ship to map out more sea floor information per unit time than would a single beam.

In Healy’s multibeam, sound is emitted through hull-mounted projectors in the form of short acoustic “pings” (which sound a bit like bird chirps when you are on one of the lower decks– bring earplugs if you have to sleep there!). The pings are 12KHz acoustic waveforms that bounce off the sea floor and are picked up by an array of hydrophones (also mounted on the hull). The amount of time between when a ping is sent and when it is received gives an estimate of how long it takes sound to travel to the bottom and back. If the speed of sound in sea water is assumed to be 1500m/s, then the depth (in meters) can be estimated as (1500)(t)/2, where t is the time (in seconds) between the sending and receiving of the ping. However, this calculation really isn’t good enough. The reason is because the speed of sound in water varies based on a number of factors, including temperature, salinity and depth. So, data collected from onboard instruments: an expendable probe (see XBT, below), a CTD that is repeatedly cast into the water (see my previous dispatch that describes the CTD), and archived data, are used to form a sound speed profile which is then used as input to the ship’s SeaBeam 2112 control computer to make corrections to the simple formula above. Using all this information, while also taking into account motion of the ship itself when estimating the time between sent and received pings, the computer can form an accurate bottom map that is made available to anyone on the ship and also shared with others back on shore through one of the various archives at LDEO.

WHOI Mooring Ops. Engineering and Field Support Group logo.

As you can probably see, there is a considerable amount of subtlety in how this works inside the computer. For example, the ship may be experiencing rolling, pitching, or yawing. Movements such as these (especially roll and pitch changes) affect how the beams are reflected back to the hydrophones, and all this must be considered when creating an estimate of far away the bottom is and what features it has. In addition, the temperature of the water varies as a function of depth and can change over time. To determine the temperature/depth relationship at a moment in time, a device called an expendable bathythermograph (XBT) and/or a CTD (described last in my dispatch) is used (e.g., once daily or when the ship moves into an area with different ocean characteristics) to measure the temperature/salinity/depth profile.

An expendable bathythermograph sitting on its launcher.

An XBT looks like a small rocket that is launched by a fixed or hand-held launcher off the ship; the ship can be still or moving. The XBT itself remains attached to the launcher by means of a very fine 2-conductor copper wire that unspools as the XBT descends toward the sea floor. As it descends, it measures temperature while its depth is estimated using an assumed falling rate. The resulting information is displayed to the user and used in forming the sound speed profile for the multibeam echosounder (and for a few other things). To learn more about the finer points of estimating sound speed in water, this link provides a number of more detailed references as a starting point.

Cruise track for HEALY Arctic West Summer Cruise 2008, Leg 4.

The principal work of the first evening included the project of Kate Stafford from the University of Washington, who is retrieving and redeploying moorings placed on the seafloor which are equipped with hydrophones to listen for the sounds of various marine mammals, including seals, walrus, and beluga whales, but with particular emphasis on recording the sounds of bowhead whales (Balaena mysticetus), the sounds of which can be heard at: http://www.dosits.org/gallery/marinemm/15.htm.

The bowhead whales are one of the key marine species in the ecosystem, and important for traditional Inuit culture — their meat and blubber a source of food, and their bones used as sled runners and in house construction. Their baleen (the horny plates in their mouths with which they filter the small shrimp-like euphausiids and copepods — their main food), as shown in the baleen model boat in Day One’s blog, was put to many traditional uses in Inuit culture: as a tough cordage for seal and fish nets; for short lanyards and lashings on sleds; as the tip of dogsled whips; for hunting snares for birds and rabbits; bent into boxes for keeping harpoon heads; made into traditional Inuit snow goggles to prevent snow blindness from glare off snow and ice; as a brow on hats for kayakers to keep spray out of their eyes; as fletching on spears and arrows instead of feathers; and as large knives for cutting ice for igloos, and smaller story knives used to tell stories by ‘drawing’ in snow or dirt. Baleen was also woven together without being cut to form racks hung from the ceiling for general storage, and as floorboards in the traditional semi-subterranean Inuit houses shown in the Day One blogs: a sort of Inuit linoleum! And, in earlier times when warfare between native groups existed, it was also used as plates woven together in the construction of armor. Making of woven baleen baskets was an innovation of the late nineteenth century begun by Barrow resident Charlie Brower.

The bowhead whale is still the principal whale hunted off Barrow. Getting an accurate count of bowhead whales has been a key issue for scientists and the Inuit people for many decades to ensure their proper management and conservation. Preliminary information on the results of the annual aerial survey, along pictures of bowhead whales may be found at: http://www.afsc.noaa.gov/nmml/cetacean/bwasp/index.php. Kate’s hydrophone arrays are deployed offshore of the 100 meter depth line at two locations along the coast in groups of three to allow tracking of whales passing along the coast. Their batteries allow them to operate for a year. In the first day of science, the arrays already deployed from the previous year are retrieved by positioning the ship over their location and generating a specific series of tones which activates an acoustic release. Floats which had remained submerged with the hydrophones are then released from their bottom weights, and the hydrophone and floats drift up to the surface where they are located by a small boat, and passed off to the ship, which then hoists them back onto the deck.

Coast Guard small boat used to retrieve moorings by snagging their floats after release from seafloor.

Once the hydrophones are retrieved, Kate downloads the data from the past year collected by the hydrophones, changes out the batteries and data recording computer hard drives, and later in the cruise will redeploy them. Of concern when retrieving the hydrophones is the ability to find them if there is heavy ice. High resolution (100 meter) satellite images have been requested by the ship showing where the ice is located.

100 meter resolution Radarsat satellite image showing ice concentrations in Beaufort Sea off Barrow, Alaska.

This imagery is from a Radarsat satellite, which is particularly useful as it can see through the ubiquitous fog. In areas where ice concentrations are heavy, hydrophone retrieval can be delayed until the ice has moved away, and the likelihood of retrieving the moorings is more certain: better to wait a bit for conditions to improve than risk a full year’s data.

The principal components of hydrophone mooring array, shown in the photo below being disconnected from the cable by Kate Stafford of the University of Washington and John Kemp of the Woods Hole Oceanographic Institution, are the hydrophone and acoustic release. When the mooring array is redeployed, a float is put over the side first. It is the float which provides the lift to allow the hydrophone and acoustic release to surface, be located by a small boat and retrieved. After the float goes over the side, the hydrophone, and then acoustic release go over, and last of all the weight for the mooring anchor is put over the side. When everything is in the water, the ship is positioned precisely over the desired mooring location, and a manual release is used which, when a rope attached to it is pulled, drops the weight at the correct location, and the entire array is pulled downward to the bottom, where it remains until the ship returns to ‘ping’ the acoustic release with the precise acoustic series of tones to retrieve it a year hence.

Hydrophone and acoustic release mooring components.

Float, weight, hydrophone and acoustic release.

Manual release for weight.

Bowheads were among the whales fairly heavily hunted during the golden days of whaling in the second half of the nineteenth century. Bowhead populations in advance of this period have been cited as about 16,000 animals, although of course, it is impossible to know for certain their historical abundance. The current estimate of the Beaufort-Chukchi-Bering Sea bowhead population is about 8,000-10,000 animals. The numbers of these whales seems to be stable and actually increasing. It is important to get good data on their numbers and habitat use as changes occur in sea ice and ship traffic in the Beaufort and Chukchi Seas.

Each year the bowhead whales migrate south through the Bering Strait in the winter to avoid seas completely covered with heavy ice, so that they can continue to surface and breathe. In the spring they migrate north from the ice edge in the Bering Sea into and through the Chukchi Sea, and many migrate north around Barrow and then east along the coast toward the Canadian arctic and Northwest Passage channels. Maps of the migration routes of some whales tagged by Alaska Fish and Game Department personnel can be seen at http://www.wildlife.alaska.gov/index.cfm?adfg=marinemammals.maps&name=8-10.jpg. As winter arrives, the whales return south along the coast to the Bering Sea.

Interestingly, the bowhead whales are often accompanied north by beluga whales (Delphinapterus leucas), the truly “white whales” of the northern seas. Because of their much smaller size, the belugas cannot easily break through the ice to make breathing holes themselves, and follow the bowhead whales using them as their own ‘icebreaking vessels’ to access more northerly waters in spring. Once in the Beaufort Sea the bowhead whales appear to distinctly prefer the waters closer to shore along the Alaskan North Slope, while aircraft sightings and tagged animals show that belugas remain further offshore in deeper waters, with a fairly distinct separation of habitat use. The fact that bowheads prefer the more nearshore waters along the North Slope makes them potentially more susceptible to increased human activities, and Kate’s project all the more important to contribute to continued monitoring of population levels.

Hunting whales by certain arctic peoples is much more than simply an avocation or way of harvesting food. This is perhaps difficult for outsiders to fully comprehend, but whaling in traditional Inuit and other arctic whaling cultures was, and still is, almost a religious or deeply spiritual enterprise, surrounded with rituals of moral purification and behavioral restrictions. It is still emphatically pointed out that one does not actually hunt whales, but one simply goes hunting for whales: it is the whale that gives itself to the hunter and whaling crew which has strictly maintained the traditions associated with successful whaling. In the arctic this invariably includes, among many other things, widespread distribution of the animals taken to everyone in the community, and other communities as well, practices which are still sustained. George Naekok, who is with us as an Inuit observer on this cruise, has been whaling most of his life.

Barrow resident George Naekok.

Insignia of the Barrow crew which includes George Naekok.

Ice at sea.

My friend Peter Wadhams has an excellent webpage describing how sea ice forms and decays, and its differences from freshwater ice (to see, click here). As he points out, because of the critical importance of sea ice to planetary climate, it is important for all of us to better understand the dynamics of sea ice. The principal difference of sea ice and freshwater ice is that when it forms initially sea ice includes salt from seawater. This makes it much more flexible and weaker than freshwater ice. But this changes over time as the ice ages and salt is gradually eliminated, so that second year ice which persists over a summer season is both fresher and much harder, particularly on our icebreaking ships when they are forced to break through zones of second year ice.

As a quick backgrounder to how much ice forms each year, and how much of it persists more than one year, I have collected several animations from colleagues which show some of this information. First, here is an animation which shows a typical annual cycle of ice in the Arctic for the first half of the year from Wieslaw Maslowski of the Naval Postgraduate School in Monterey, California:

Next, here is an animation by Wieslaw of sea ice thickness showing the area off the Canadian Arctic and northern Greenland where second year or multi-year ice commonly persists, and few if any ships, even icebreakers, dare venture:

Finally, here are two animations by Wieslaw that show cycles of stress in the ice. This one shows shear in the ice, arising from storms that open leads (cracks in the ice), which later close to form ice ridges:

And this one shows the stress as areas of convergence (blue) and divergence (red) in the pack ice of the Arctic during the winter months:

Ocean mixing and the effects of storms on sea ice are key components of the research being done by the scientists on this cruise. We are hoping to better understand the mixing of the waters in the Arctic and heat transport from lower latitudes and coastal Arctic waters to the depths of the Arctic Ocean.

The first science operations on HEALY began shortly after everyone was aboard, in the traditional way: by ‘grabbing water.’ This is done using a circular metal frame called a rosette, from which water sampling bottles, called Niskin bottles (named after their inventor) are lowered in an open position into the ocean, and a closure mechanism is electronically activated to capture water from various depths.

A CTD cast.

Niskin bottles.

Along with the Niksin bottles, the rosette includes a CTD. CTD stands for conductivity, temperature and depth; a CTD “cast” (vertical lowering and raising) allows a profile of salinity with depth to be calculated from conductivity of seawater once corrected for temperature and depth. These vertical casts profile the heat content of the Arctic Ocean, and mixing of coastal waters freshened by rivers with the deeper ocean waters. Whereas this is one of the main goals of this cruise, the work is underway: not bad for a first day at sea. And on the morrow the science will start in earnest, hopefully still amid the ever-fascinating ice.