Scott Inlet - trawling and long lines

One of the glaciers

This is the forth installment on my field work in Scott Inlet, Baffin Island. Previous installments can be found here, here and here.

17 Sept 2013 – the ship spent the night just outside Scott Inlet starting out out at anchor, but wind and swell caused it to endlessly rub against the anchor chain. The mate, who was on watch, decided to start up the engines, pull the anchor and motor around for the night. All the while, small chunks of ice butted against the hull right beside my bunk which left me with visions of the sinking Titanic. No sleep was to be had, leaving us all looking rough around the breakfast table in the morning.

Over the course of the day we completed 5 trawls – the first time the Nuliajuk had done a bottom trawl. With each trawl, the turn-around time with the equipment sped up as everyone figured out what they were doing. Each trawl was slightly deeper than the last as no one knew exactly how much cable the trawl net had (it turns out around 900m worth). The catch included: Greenland Halibut, Flounder, Arctic Cod, Polar Cod, Alligator Fish, Snail Fish, Northern Shrimp, Striped Shrimp, other assorted shrimp, 2 species of skate, Hookear Skulpin, Eel Pout, and assorted jellies, sponges and stars. I saw none of the animals as I stayed on the bridge taking notes on times, locations and depths while trying not to get sea-sick (I could have popped down to the lab – but didn't think my stomach could take it).

For the night, we retreated to anchor in Refuse Bay. It was nice not to have to dance around to get my socks off at the end of the day.

18 Sept 2013 – We took the day to circumnavigate Sillum Island, one of two islands that Scott Inlet branches around. The aim was for me to do CTD casts while the long-lines were being set up for sharks. The occasional depth sounding of the chart didn't even hint at how complex the bottom topography is, multiple deep pools of 700 m and more are separated by shallower sills. Bumps and dips break the flat of the deeper pockets. Mostly, the depth sound returned a hard signal meaning the bottom was probably rock, but occasionally, the signal would return spread out suggesting isolated muddy patches (or something else).

Against the electric blue of the glaciers, the fresh snow looked dirty. In gullies where glaciers reached the water, calved off chunks floated away. These bergy-bits often sported whimsical shapes reminiscent of ancient monsters or partly submerged houses.

I finished the day with 47 CTD casts over a wide area, downloaded and backed up to three places (I'm mildly paranoid about losing data).

Greenland Shark complete with copepod (shark is on its back)

19-20 Sept 2013 – Over the next two days we fished for Greenland Shark deep within Scott Inlet (it was delightfully calm in the sheltered Inlet, I could set a cup of coffee cup down and not have it instantly spill everywhere). We used a long-line bated with squid for the sharks. A long-line is exactly as it sounds, a several hundred metre long line with shorter lines attached every few metres ending in hooks. Anchors weight down both ends keeping it on the bottom, which in our case was around 600 m. Off of the anchors at both ends were buoyant ropes attached to floats so we could recover everything (both ends in case we encountered a snarl and had to cut the line – then we could start again at the other end). Both days, the whole mess of lines, anchors and hooks was left in the water for 24 hours.

While I was there (shark fishing continued after I left), we caught 14 live shark and several more that had been snacked on. Sizes ranged from 1.6 m (baby size) to over 3 m with a good mix of males and females. We didn't catch anything else, so why were the shark even there? And what were they eating? The sharks were measured, tagged and tissue and blood samples were taken. The question as to why we needed the centrifuge was answered since the blood was spun to separate out the plasma.

Most sharks had a copepod parasite (Ommatokoita elongata) attached to their corneas. Each parasite dangled a finger-length yellowish egg case from the shark's eye, no doubt impairing the shark's vision (but, they live so deep, vision is probably not critical for their survival).

We brought on board a couple of shark heads (the assumption was that other sharks had eaten the rest of them). I took the opportunity to get a close up look. The Greenland Shark doesn't have flashy teeth like a Great White Shark does. Instead, it has tiny teeth reminiscent of a saw blade or razor wire. These shark bite and twist, effectively removing chunks of its prey. Up close, the teeth looked deadly.

Scott Inlet - Getting to work

The bear looking annoyed with us

This is my third installment about this years field work. First is here, second is here.

A polar bear sleeping on a rock greeted us the first morning in Scott Inlet. The bear wasn't happy to see us as we rudely brought the ship in close to get a good look at him (a young male). The bear got up and moved further up the slope, casting disdainful glances our way. So far, I've seen a polar bear every time I've gone to the Arctic.

Steep faces on each side of the inlet bracket the narrow band of water of the inlet. The orange and black stained cliffs are high enough that base jumpers use the area – how they get up the cliffs in the first place baffles me, gaps to climb up were rare and filled with glaciers dripping in slow motion towards the sea. The inlet walls would fit the landscape in 'Game of Thrones' north of the wall, or exist in Middle Earth. Off one of the cliffs flows the most peculiar waterfall I've ever seen. It cascades off the top, then vanishes mid way down. Does the water freeze into snow? Where does the water come from? Below the water was just as shear - our depth sounder listed depths around 200 m and greater only a short distance form the cliffs.

Cliff face at Scott Island

The inlet appeared strangely devoid of life. A few Arctic Fulmars glided by, but never conglomerated around our ship even when we were offering up a free lunch (excess bait squid). Olive green jellyfish about the size of baseballs bobbed in the water. We knew narwhal were in the area, but never saw them – perhaps our depth sounder scared them off.

In 2012, three lines of receivers to listen for tagged fish, plus my two oceanographic moorings and some marine mammal listening devices were left in the water (to a total of 36). We came prepared to re-install these moorings plus add four additional receiver lines. As a result, the back deck of the ship was consumed with 200lb anchors weighing the aft end down. The first order of business was to deploy a batch of new receiver moorings before recovering any.

Instead of depth contours, the chart only listed a few depth soundings leaving most of the bottom topography to the imagination until mapping could be completed (the Nuliajuk is heavily involved in mapping when not doing our work). Depths for the mooring locations were needed to ensure we used the right type of float (non-compressible floats for the deeper moorings). As we checked depths, I did a line of CTD casts. Then we turned around and deployed a line of moorings. A process we repeated several times over several days.

Once the deck was cleared a bit we began recovering the previous year's moorings. Each mooring was fixed to its anchor with an acoustic release, essentially a hook with enough electronic brains to respond to a code sent from the surface and open the hook. Attached to the release is a length of rope holding the instruments ending in a float. From the ship, we call the release and have it uncouple – then the instruments are pulled to the surface by the float.

Several of us kept look out for the floats as they popped up. When a float was spotted, the zodiac zipped over and pulled in the mooring then transferred it over to the ship. Once the mooring was on board, we cleaned them up – an easy task as nothing much grew on the mooring lines and instruments. If we had put these instruments in temperate waters we'd be scrubbing matts of seaweeds and mussels off. Instead, there was a light growth of algae that wiped off with a towel.

One of my moorings - nothing fancy

One of my thermistors flooded. When I opened it up the batteries we so corroded I couldn't read any of the writing on them (batteries were removed carefully avoiding the battery acid). The rest of the instruments were fine. I downloaded each instrument, changed the batteries and re-programmed for a another year. I only briefly looked at the data to check if each instrument worked properly (I'll spend the next while looking at the data in more detail).

Kevin (another scientist) and I tackled the marine mammal recorders, instruments I had never worked with before that use large numbers of D cell batteries. By actually reading the instructions, we readied most of them for re-deployment. Unfortunately, one instrument needed a specialized wrench, which we didn't have. The wrench was to arrive with our replacements, so I assume it has been dealt with by now.

The mooring work was a success – all the moorings from 2012 were recovered and more moorings were put out.

Next up, some fishing...

Heading up the Baffin Island Coast

A view of Clyde River from the sea

The first step before heading to Scott Inlet was getting approval from the local HTA (hunting and trapping association) to tag fish, install moorings and collect data. Before leaving solid ground, the four of us (as there is only room for four scientists on the ship) waded through the fresh snow to the HTA office located in a red shack beside the community freezer.

The office was utilitarian, lit by florescent lights and a lone incandescent bulb. An uncomfortably low ceiling made me feel it was risky to stand up tall. Once white vinyl tiles covered the floor. In an economy of surfacing, the same tiles covered the chipped white painted conference table – edges held down with masking tape. Most of the table surface was consumed with a big map of the area. The walls were decorated with maps, a variety of posters including a graphic one on caribou diseases, and a wanted add for narwal tusks from someone in Vancouver who “will pay a good price.” Lined up along the walls were boxes of ammunition, rubber boots, ropes, and bolts of dull coloured fabric.

A few moments later, a group of men and one woman arrived. Introductions were made and we all sat around the conference table. We worked through a translator, an HTA member with good English, to explain our work. The group kept stern faces as we explained how the acoustic receivers work and our interest in the Greenland Halibut and Greenland Shark. The HTA members were very interested in if our instruments affect the marine mammals – an important food source for them. The agreed that knowing more about the local Greenland Halibut would help them in setting up a commercial fishery, a potential income source for the community.

However, they were baffled as to why we were interested in Greenland Shark. To them the shark were at best a nuisance. You can't eat Greenland Shark without serious preparation as the flesh is toxic and contains high amounts of urea. If you have time, these sharks can be fermented and rendered safe to eat, but this is not something the Inuit traditionally do. Nigel, our shark expert, made a compelling explanation as to why we should care about these shark. I've been working with Nigel for a few years, his shark work takes him from Africa to the Arctic and his passion for these animals rubs off on me, so even with cold feet I'm excited to see them. The Greenland Shark are the top predator on the bottom of the polar seas and are needed to keep the ecosystem in balance. The HTA members appeared to remain skeptical, but willing to humor us. Ironically, the HTA chair's last name translated to English means 'shark'.

The HTA granted their permission asked for a community wide meeting to show everyone what we had accomplished when we finished. While in Scott Inlet, a local community member was to accompany us to see what we were doing, which has happened in previous years. We were also asked to bring back some Greenland Halibut back for the community and to take supplies to a group of hunters stranded in Scott Inlet. After the meeting, we begged a ride (there is a taxi in town, but its availability is never certain) to get our gear down to the water's edge and then transferred to the Nuliajuk (the ship).

We couldn't leave until the next afternoon as gale force winds and 4 metre waves were pounding the Baffin Island coast. Once conditions improved, we pulled anchor and headed north. I looked around the ship, which consists of a bridge, small lab the size of an en-suite bathroom, a kitchen/eating area, two tiny cabins and a v-berth designed to sleep six with less floor space than my bathroom. This was the total inside space to be shared with 10 others. In the v-berth, I had the bottom bunk of three on the starboard side, it took a special sort of un-graceful yoga move to get in.

On the 12th of September, Jacob, the local observer, joined the ship, we loaded groceries and headed north. On our way out of Clyde Inlet, Jacob pointed out a passing cliff with three red streaks running down the face. He said that there was an old story about a man, a dog and a bear. All three fell off the edge of the cliff leaving the red streaks, but only the man and bear survived. Occasionally, sled tracks are found behind bear footprints, as though the bear now pulls the man's sled. I took pictures of the cliff, but the snow obscured the three red streaks.

As expected, it was rough out in Baffin Bay, the large swells tossing the ship about (and spilling vanilla in the galley, giving the ship a pleasant odor of fresh baking). The Nuliajuk is very bouncy and I tend to get sea-sick. To keep a horizon in view, I stayed up on the bridge – which also gave me a nice view of passing icebergs (I'll write a whole post about the icebergs later).

By midnight we arrived in Scott Inlet to start work in the morning. More to follow...

Getting closer; report from Clyde River

Iqaluit airport - it looks like a dissected pelican
case to me.

It was snowing when we landed in Iqaluit - just lightly, but it was snowing. Our layover was short and were expecting some critical equipment to be dropped off. Stress levels increased as our departure time approached without our equipment arriving. We were waiting for a centrifuge (not sure what we need that for) and the transmitter for the acoustic releases (absolutely critical for our work). At the last minute the equipment arrived, we handed it off to the airline and hopped on the plane.

As I walked through the gate a sticker was put on my boarding pass that said: "First Air regulations provide that no hotels, meals or transportation will be supplied if you are over or under carried from your destination" and we were told that weather in Clyde River looked bad and we were likely headed to Pond Inlet instead. A few hours into the flight we joked that it would be nice to see Pond Inlet, then the pilot came on and told us were would be landing in Clyde River in a few minutes.

It was snowing harder when we arrived, a snow that has arrived about a month earlier than expected. I hope it doesn't last. The clouds were low, so I couldn't see much of the surrounding area. The ground is strewn with massive boulders, no doubt dropped off long ago by a retreating glacier. The airport is a small building with a single common room. We stepped inside and watched our luggage be dumped on the ground in the muddy slush in the parking lot. Fortunately, I pack for that sort of thing. As we went outside to collect our gear, a stranger offered us a lift into town and we accepted.

The one hotel in town is closed for renovations, so we are staying at the Inuit Cultural Centre. When I was called to make a reservation I got the impression I was signing on to stay in a barrack style group accommodation with rows of bunk beds - I was totally wrong. I have a spiffy room to myself with a bathroom (I didn't expect the luxury of my own bathroom). The centre is only a few years old and absolutely lovely. We arrived a 4pm on a Sunday, and I didn't know there is no food available at the centre and the Northmart, the only store in town, is closed for the day. Fortunately, another guest took pity on us and gave us chicken noodle soup.

The windows in the common room over look the water (a bay I think). A fuel tanker is at anchor replenishing the town's fuel supply for the winter. Our research vessel isn't here yet - we hope it will arrive soon. We don't have permission yet for our work in Scott Inlet. Monday we meet with the local HTA (hunting and trapping association), the group that can authorize our work, hopefully, they grant us their approval and we can set sail for Scott Inlet.

As a tangent: Since I've been just waiting around looking out to the bay (the town is out of sight) I've spotted a Raven, a Lapland Longspur and an Iceland Gull.

Where I'm heading...

Might see some of these

I'm heading up north again in a few weeks – I won't believe I'm actually going until I get on the plane as delays are typical, even expected. Excess ice has already pushed our schedule back and it's impossible to predict what else might come up before I leave.

This year I'm conducting oceanographic sampling in Scott Inlet, a remote fjord on northern Baffin Island. Two moorings were installed on my behalf last summer (I couldn't go because I was 8 months pregnant at the time). If luck is with me, I'll get those moorings back, download the data, then put them back into the water for another year. Additionally, my plan is to take as many CTD casts as I can and help out with the other work that will be going on (fish tagging, acoustic moorings and maybe shark wrestling).

I fly into Clyde River, a small town I've never been to. All I know so far about the town is the only guest house is closed for renovations. After a night there, I'll be getting on a small research vessel. I've been on this ship before and learned that it gets quite bouncy in rough weather and I tend to get sea-sick (will pack gravel).

To get to Scott Inlet, we'll have to skirt the edge of Baffin Bay a place I've read a lot about. Baffin Bay is a large body of water bound by Greenland to the east, Baffin Island to the west, Ellesmere Island to the north and Davis Strait to the sound. Obviously, locals have known about this place for as long as they have lived there (since about 500 BC). Wikipedia says that John Davis was the first European there in 1585, but I wonder how far the Vikings got exploring the area as I recently saw a documentary about a potential norse trading post on southern Baffin Island (no idea if the show was presenting a fringe idea or not).

Even though Baffin Bay is choked with ice in winter, European whalers frequented the area early in the age where European powers sent sail boats exploring the Arctic. There's a large polyna (the North Water Polyna), much further north than I will go, that's highly productive and home to many marine mammals. Baffin Bay is one possible starting point for the North West Passage and many explorers passed through including Sir John Franklin. Interestingly, a B-52 crashed on the ice in 1968 with its nuclear payload.

A couple hundred km north of Clyde River is Scott Inlet, a narrow fjord filled with large islands which I know little about. This time of year the daily mean temperature is 0 degree Celsius, so it could be quite cold. I'll have to pull out my fuzzy gloves and wool long johns. I wonder if I'll see northern lights?

Tilting Isopycnals (the simplified version)

Sunset over Cumberland Sound

One of the things I’m attempting to determine is if the Baffin Island Current*, which passes outside of the mouth of Cumberland Sound, bends into the sound. Last summer, we were able to conduct two rounds of CTD** casts at regular intervals across the sound's mouth. Unfortunately, I wasn’t actually there as I was too pregnant to be at sea. I doubt I would have fit in the bunk as the ship we used is a particularly cramped research vessel (picture here).

Even though it was cramped, the ship had a hull-mounted current meter. Unfortunately, the instrument wasn’t turned on. No one on board had the knowledge to fiddle with it, so I missed out on that data (that’s the way it goes sometimes). Without measured currents, how does one infer water flow from CTD data?

The Baffin Island Current is geostrophic, that is, the pressure gradient force is balanced by the Coriolis force. In this case, friction and tides become unimportant and can be ignored when calculating current flows.

The pressure gradient force is the weight of water as the sea surface height is not at the same everywhere. This force is always directed from areas with high pressure to areas of low pressure. Without a balancing force, a parcel of water will move from the area of high pressure to the low one. But, there is another force out there to balance with - the Coriolis force.

Actually, the Coriolis force isn’t a real force; instead it is like an imaginary friend that shows up to solve a problem. It pops up when we treat our rotating planet as though it’s an inertial frame of reference to use Newton’s laws. Newton's laws form the base of ocean physics - and most other things that aren't moving too fast or are too small. Now, we’ll move on to pretending the Coriolis force is real. This force acts in different directions depending on the hemisphere, since I work in the northern hemisphere, I’ll take it as acting to the right.

As soon as the parcel of water from above starts to move because of the pressure gradient force, it will be acted upon by the Coriolis force and deflected to the right. The result will be a current that flows along an isobar (line of constant pressure) - a geostrophic flow.

In the ocean, pressure is difficult to measure. Fortunately, pressure is related to density and density depends on salinity and temperature which I measured. In the Arctic, where Cumberland Sound is, density depends mostly on the salinity, however, since I measured both I used both. I’ve calculated density and plotted up lines of constant density, which are called isopycnals. From plotting a cross-section of density, isopycnal slopes tell us if water flows in or out of the section, which is exactly what I’m looking for (note: isobars and isopycnals have opposite slopes).

From isopycnal slopes, a relative velocity can be calculated as currents move faster where the isopycnal slopes are steeper. Actual velocities would have been nice to get, leaving me wishing I had been on the ship to turn on the current meter. However, relative velocities still answer my question of whether the Baffin Island Current bends into my site. The answer is yes it does.

*The Baffin Island Current is the official name of this current which passes along the coast of Baffin Island (a nice diagram showing it can be found in this paper). Many currents have assigned names, the Gulf Stream and Kuroshio are perhaps more familiar examples. 

**CTD stands for Conductivity Temperature Depth. From conductivity, salinity is calculated. This instrument samples the water as it descends directly down from the ship resulting in profiles of these properties with depth.

Waves in the Ocean - redone

A photo of waves taken from the safety of the shore

Some time back, I wrote about how, once you are out of sight of the shore, waves in the ocean look the same at different heights (original post is here). I reworked the post, removing the helicopter scariness for the UVic Ocean Student Society's blog - find the post here.

Something on glass sponges...

Here I am building a mooring

For my masters work I looked at flow over a local glass sponge reef. It turns out that how the tides interact with a sub-surface ridge may influence the conditions the sponge reef lives in. I wrote a little about it for the UVic Ocean Student Society here.

Getting a sample of water

one alternative to taking water samples...

As an oceanographer, I often think about how to sample the water I’m interested in. Generally, I prefer using instruments that measure a property in place returning just an electronic data file, but sometimes, water must be taken for analysis which raises the question: how do you get water from the ocean and into a lab? The simplest solution is a bucket at the end of a rope - a technique I’ve found myself using in the past. This equipment is easy to find and easy to use. The downside is you can only get surface water this way. Getting waters from intermediate depths takes fancier gear, and it took a long time of trial and error to develop the instruments needed to collect water from these depths.

A theoretical idea…

Water sampling equipment started from an idea presented at the British Royal Society early in its history from someone who never went to sea. Robert Hook designed a box of wood to be lowered on a line. Water flow held the end valves open on the way down. When the instrument reached the desired depth, it would be hauled up, and the change in direction would close the end valves. This design ultimately evolved into our modern water sampler, however, the original wasn’t practical. The wood would swell in the water and no seal was maintained - if you hauled back the sampler and it actually contained water, there was no way to know it came from the targeted depth.

A reality check…

To reliably work, water sampling instruments made the leap from theoretical designs to functional equipment via multiple design iterations (I often wondered how much of this occurred on a deck of a ship where some poor technician was trying to make this theoretical, lab-built equipment work).

By the time of the Challenger Expedition (1872-76) a working instrument existed - a stop-cock water bottle. This sampler had spring-loaded stoppers for both ends. When it was being lowered into the ocean the stoppers would be open, allowing water to flow freely through the bottle. At the desired depth, the bottle being lowered, was pulled up slightly, allowed to fall back and then jerked to a stop - action that would close the stoppers and trap the water inside.

Several design iterations later, and still in common use, is the Niskin bottle (designed in the 1960’s). Niskin bottles are made of plastic to reduce sample contamination and the end caps have rubber washers to improve their seal. These bottles are lowered down a wire in the open position. When the bottle reaches the desired depth a metal messenger, basically a metal bead that clips onto the wire, is sent down the wire to trip the bottle closed. An added advantage is these bottles can be used in series, allowing for multiple samples to be taken at one time. They can even be arranged in a rosette for more detailed water collection schemes.

Do we need to take the water…

“To replace the laborious analysis of recovered water samples the marine scientist may employ a single sensing unit which will telemeter back to him, or record on tape, data on the temperature, salinity, conductivity, oxygen content and sound velocity of the water in which it is placed.”
                   - Historical Instruments in Oceanography by Anita McConnell, 1981

Water sampling is still necessary for many things, however, electronic sensors can be deployed for long periods of time, reporting back parameters which can provide an ongoing record at that location. Ocean networks like Venus and Neptune provide ongoing reporting that could never be obtained from water sampling alone.

As a tangent - the photo is a simple mooring I built with electronic recording instruments (salinity and temperature) that was deployed for a year, part of that under ice. Yes, it looks like a pile of rope.

The book I haven’t read

my copy looks exactly like this

This week marks 50 years since Rachel Carson’s ‘Silent Spring’ was published.

I care about the environment in part because it's the only environment we have to support us, thus it's our lifeline. I agree with Carl Sagan when he wrote “the simple fact is that we are performing unprecedented experiments on the global environment and in general hoping against hope that the problems will solve themselves and go away.” I’ve been aware of Rachel Carson’s book and how it is credited with starting the environmental movement since I was in high school - yet I’ve never read it (yes I should read it - as soon as I find a copy in a used bookstore I’ll pick it up).

I can’t comment on ‘Silent Spring’, I have however, read another book by Rachel Carson, ‘The Sea Around Us.’ My grandfather gave me his copy of the book when I switched into oceanography for my undergrad. In the front cover the inscription says ‘this book is presented to H.B. Hunt as an award for excellent meteorological observations carried out in S.S. Lakemba on a voluntary basis during the year 1951.’ He must have been presented the book when it was brand new as it was published in 1951. By the early 90’s, it looked slightly ratty on my book shelf and I didn’t read it then, but I kept it. A few years ago I realized who the author was, so I decided to pull it out and finally read it.

The acknowledgments read like a who's who of early oceanography - all names of people who made major contributions to the field. In addition to her background in marine biology, she did her homework. I found it an easy read that made the ocean seem magical. Consider her description of the tides:

There is no drop of water in the ocean, not even in the deepest part of the abyss, that does not know and respond to the mysterious forces that create the tide … no other force that affects the sea is so strong.

Or surface waves:

It is a confused pattern that the waves make in the open sea – a mixture of countless different wave trains, intermingling, overtaking, passing, or sometimes engulfing one another; each group differing from the others in the place and manor of its origin, in its speed, its direction of movement; some doomed never to reach any shore, others destined to roll across half an ocean before they dissolve in thunder on a distant beach

What I also enjoyed about the book is what she didn’t mention. Places like hydrothermal vents hadn’t been discovered yet - so the belief at the time was that the abyss was barren of life. Ideas like plate tectonics were not yet widely accepted so, the ocean floor was presented as static. We have learned so much in the time since the book was published.

Note: the picture came from Wikipedia

Some icy bits

A different menace to shipping

I’ve been sitting at my desk with the view of the beautiful summer day on my island in the Pacific thinking about sea ice. The ice in Cumberland Sound is still delaying science work there. On top of real life ice woes, I’ve been reading about sea ice.

Sea ice is surprisingly complex. After a morning’s reading I’ve had to look up three terms I hadn’t run across before: lamella, nilas and breccia. But, if I take a step back, ice in the Arctic can be broken into four categories:

1 - Polar Ice Cap - this makes up about 70% of ice found in the Arctic Ocean. This ice stays year round, however it isn’t static. New ice is being included into the cap while older ice is carried away. Overall, the cap is rotating in a disjointed fashion clockwise.

2 - Pack Ice - Wind blew this type of ice into my path when I was up in the Beaufort Sea a few years ago. There was pack ice as far as I could see in every direction at a time when clear sea was expected. This ice is made up of floes, which are separate chunks of ice. About 25% of the Arctic Ocean is covered in pack ice.

3 - Fast Ice - No, it isn’t moving anywhere, in fact, it’s land fast. The ice extends to the bottom where it attaches. This ice type is seasonal, thickening to 1-2 m in winter while disappearing entirely in summer. As an aside, funky things can happen when pack ice and fast ice meet.

4 - Ice Bergs - These are mostly found in the North Atlantic and come from chunks of glaciers on Greenland and Elsemere Islands breaking (or calving) away. They then drift south becoming a menace to shipping.

Image is from here.

What isn’t happening...

Last summer, I was oceanographic (CTD) sampling in Cumberland Sound by 23 July. This year work was scheduled to start 18 July. As I’m over 6 months pregnant, an undergraduate student was hired to do the field work in my place. He helped me in a lab class last fall, so I know he's a good, reliable worker. This trip is his first field work of this kind (other scientists will be there to help him out). No matter how things work out, it's a good opportunity for him to see a part of the world that not many people get to see.

It turns out that Cumberland Sound is almost completely covered in ice. For comparison, this time last year all we saw were a few icebergs. At the moment, the ship can’t even get into the sound - so the ship is going somewhere else to do some mapping until conditions change.

It’s amazing how different conditions are just a year later, I’ll have to look for some satellite photos to compare. I’ve prioritized my sampling plan, so hopefully the most important stations still get sampled. All I can do now is wait and see. Unfortunately, my student is stuck sitting in Pangnirtung with the other scientists waiting...

At this point no-one knows when sampling will begin.

Ice holes

Out in the middle of the frozen Arctic and Antarctic waters are pockets of open water called polynyas (Russian for ‘ice hole’). I first ran across polynyas when I read ‘Ice Station Zebra’ by Alistair MacLean as a teenager - I understand the book was made into a movie in 1968, but I haven’t seen it. A cold war thriller, the novel centers on a nuclear submarine traveling under the Arctic ice pack on a supposed rescue mission that results in sabotage. Getting through the ice becomes critically important to the submarine’s crew - and normal pack ice is much too thick to break through. A polynya provides the perfect way through the ice, but why are they there?

It seems paradoxical that open water can co-exist with below freezing air temperatures. Shouldn’t the water just freeze? Polynyas form only under very special conditions. First, a physical barrier is needed to stop ice from moving in. A point of land or ice bridge would do the trick. Next, mechanisms to stop ice formation must occur which can be broken into two broad categories.

If the forming ice is removed by some mechanical process, it’s called a mechanically forced polynya. Appropriate mechanical processes include wind, currents and tides. Because ice is being formed, then moved away, the surface waters would become extra-salty - as sea ice forms it rejects the brine. This salty, cold water would then sink.

The second type of polynya is formed by convection. Convection is a common heat-transfer process that can be found in any kitchen. It explains how a pot of water is brought to the boiling point from a heat source below. The element heats the bottom layer of water (conduction) and this water rises heating water further up (convection).

In Arctic waters (and Antarctic waters I think - I haven’t been looking into what happens in the Antarctic), the lowest layer of water is quite warm, about three degrees Celsius. It stays on the bottom because it’s dense (i.e. heavy). If a process, like tides or upwelling, brought this warmer water up to the surface, it would keep the surface waters from freezing. An added bonus when deep waters are brought to the surface is that they tend to be nutrient rich, supporting diverse life.

As with everything in nature, polynya formation is complex. Typically, they form due to a combination of factors and can even create their own feedback loops.

making ice

Sea ice in the Beaufort Sea

I took thermodynamics in 1992 - just the other day was the first time I needed it. Formulas memorized 20 years ago are long gone from my head forcing me to crack open old textbooks. I've been moving these books around for years, so it's good to finally need them.

The first book I looked at was a first year oceanography textbook where the authors seemed confused about the difference between heat and temperature. An undergrad physics textbook turned out to be much clearer.

Heat and temperature are related, but they are not the same thing - a point that is often blurred in our everyday language. Temperature is a physical property of an object and easy to measure with a thermometer. For my project, I spent a lot of time last summer measuring this property in seawater and I'm planning on gathering more of this data in a few weeks. Temperature puts a number to ‘hotness’ or ‘coldness’.

We know that the molecules making up everything are in constant motion. The energy found in this motion is know as heat which is reported in joules.

Why am I suddenly looking at heat and temperature? I want to know if cold winter waters produced in Cumberland Sound will form the bottom water which is over one kilometre deep. If I can’t make this water locally, then it must come from somewhere else. To see if bottom waters are being made in winter (as I don’t have data from that time) I’m cooling down the summer water (which I measured) to the freezing point, making it denser. Then, I’m looking at the denser water to see if it will sink to the bottom. The temperature difference between the summer value and the freezing point is related to the heat loss - so I’m also able to look at the amount of heat that needs to be removed and see if that number relates to winter conditions.

These calculations are very rough as ice formation is much more complex than just cooling surface waters to the freezing point - but, it's a place to start.

Getting tangled in jargon

A crab drawing of mine - completely unrelated to the text

Since I spend most my days with people in ocean science and people who have been around ocean scientists long enough to understand what they say, I often don’t notice ocean science specific jargon as such. I got caught out the other day using ‘water column’ when asked what I do - I didn’t even realize I was using jargon until she said she didn’t know what that meant.

Imagine you are out on the ocean on a rubber raft. If you looked straight down over the side, from the surface of the water all the way down to the bottom would be considered the water column.

On another note - a blog post I wrote about how we measure temperature in the ocean has been posted here.

talks about climate change

I'm still at the Ocean Sciences Meeting. So far, every session of talks I attend are in rooms with a capacity for a great number more people than show up. As I look around, there is always an uneven sprinkling of people throughout the room.

Wednesday, 22 February 2012 - Day 3

An interesting point came up that I hadn’t considered: coral reefs are studied with much more frequency than the equally (or more so) common eelgrass beds. I wonder if the colourful fish make are simply more appealing? Although, fascinating creatures live in eelgrass.

One of the sessions I attended was titled ‘Imaging the Ocean Interior’ - I was excited about one of the last talks that hinted at exploring underwater ice caverns with acoustics. Two of these talks focused on re-using the seismic survey data collected by oil and gas companies. This is data collected to look at what is beneath the ocean floor, but it can provides interesting information about the structure within the water column such as internal waves and boundaries between layers.

A cool use of acoustics is looking at really small things. One group is able to ‘see’ targets down to 0.8 mm in size. This same group has simultaneously developed an optical system, essentially an underwater microscope, that sees to 25 micrometers giving a clear view of phytoplankton. Both these techniques can be deployed into the ocean, reducing the need to bring samples back to the lab.

The afternoon wasn’t without disappointment. The under ice exploring talk focused on a project they wanted to do, not one already completed. I’ll have to attend the next conference to see their results.

Thursday, 23 February 2012 - Day 4

Melting glaciers are an iconic symbol of climate change

- J. Bamber, Nature, February 2012

Another early start with ‘Dynamics of Fjords and High Latitude Estuaries’. A lot of focus is being put on the fjords in Greenland because of the melting ice sheet there. As this ice sheet melts it adds about 0.09 mm each year into the oceans contributing to rising sea levels. The majority of fresh water released from a glacier is due to calving icebergs and melting from beneath the glacier that passes over sea water, only a small portion if due to run off. Increased fresh water can change the dynamics of fjords making an interesting basis for a scientific study.

As a tangent - I wish I brought my camera so I could include some pictures!

my brain is full!

I’m at the Ocean Science Meeting in Salt Lake City Utah. After the end of day two, I can officially say my brain is full.

Monday, 20 February 2012 - Day 1

I got up early to attend one of the first sessions of talks titled ‘Integrating Oceanography and Animal Tracking - the Ocean Tracking Network’ as my work is part of this project. An interesting point was raised: “results will not reflect the properties of fish ‘untouched’ by the hand of man.” Putting a tag inside the fish will alter its behavior, at worst the surgery could kill it at best it might swim away after a really bad day.

Tagging fish can answer questions like: how long a fish remains in an area, if they make daily migrations or movement related to tides, or how many of a population stays put compared to numbers that go wandering.Tracking projects were discussed from South Africa to Australia to Canada.

The migrations of the American eel made an interesting tracking example. These eels spend most their lives in fresh water ranging from Greenland to the north coast of South America. At the end of their lives, all of these eels migrate to the Sargasso Sea to spawn. We know close to nothing about this migration, but we do know their population dropped dramatically in the last 30 years.

To learn more and potentially take preservation measures, eels were tagged in the St Lawrence River. 145 eels were tagged in 2010 and 2011. From the acoustic signals recorded we learned that they don’t migrate as a group, and they take advantage of tides and darkness to move. Temperature data showed that unlucky eels were eaten by Tuna and shark as their stomachs are warmer than the surrounding waters.

A twist on finding tagged animals is in testing off the coast of Nova Scotia. Receivers are put on a big enough animal. Since, grey seals range over large areas, they are ideal predators to lead us to feeding hotspots while recording signals of other tagged fish.

Other talks I went to delved into how energy is dissipated from surface waves, decay rates of white cap foam and temperature fronts in the ocean. I found the images of currents that form jets in the southern oceans fascinating as I had no idea it was so complex - the pictures looked like a chaotic mass of snakes.

Tuesday, 21 February 2012 - Day 2

I started with attending Arctic talks in a session titled ‘The Arctic and subpolar North Atlantic as the pacemakers for climate change.’ I’m aware that there is a sea surface height difference between the Pacific, which is higher, and the Atlantic, this results in flow across the Arctic to the Atlantic. What I didn’t know is that fresh water is accumulating in the Arctic, specifically in the Beaufort Sea as a gyre. This gyre as increased in fresh water content significantly since 2003 by 5400 square kilometers. What happens when this fresh water is released? This and other fresh water anomalies could potentially impact our climate if they stop or slow down the Meridional Overturning Circulation - this is a basin wide process in the Atlantic that includes the warm water from the Gulf Stream the keep Europe warm.

I also found it interesting that Arctic observations peaked in the 1980s - cold war related?

My afternoon was filled with talks on flow/topography interactions, an area I looked at in detail for my masters work. The room was packed, meaning this area is very much the focus of active research.

How deep is it?

Once a lead line was the only way to figure out how much water was beneath your ship. Now, there are all sorts of options for determining ocean depths from echosounders to satellite images. I suppose one could even venture out with reel of line and a weight, but not me as spooling in kilometres of line is quite tiring.

I wrote about how our technology evolved for determining ocean depths here.

Plastic in the ocean – a depressing thought

A myctophids (photo by G. Hanke RBCM)

“No scientist would ever use the state of Texas as a unit of measurement” 

       - Captain Charles Moore

My husband and I went to a talk by Captain Charles Moore recently. He wrote 'Plastic Ocean', a book I'll read and write a review of (we have been planning to get the book for some time). He brought up some interesting and depressing points about how much plastic is in our oceans and what it's doing to the life there.

Only about 10% of the garbage that gets into the oceans washes ashore; the rest is concentrated into the mid-ocean gyres. An unfortunate side effect of our convenience-based consumer lifestyle is that much of the garbage produced is plastics, which float and don't breakdown. It takes approximately 6 years for the garbage to travel around a gyre and the average life of the garbage in a gyre is 10 revolutions – that is 60 years.

At first the plastics resemble what they started as – a milk crate, a laundry basket, etc. Since plastic presents a hard substrate, algae eating fishes claim larger chunks as shelter and keep the surface fairly algae free. This clean plastic eventually gets colonized by barnacles and corals creating a new multi-level trashy ecosystem - with algae as the base, then on to herbivores, planktivores, secondary invertebrate consumers, and so on ending at the top predators (large fishes, birds, dolphins and relatives).

As hard-shelled invertebrates grow, their mass overcomes the buoyancy of the plastic. The reef sinks, and over time, the attached organisms decay or dissolve in the cold ocean depths. Buoyant once again, the plastic floats to the surface and the cycle of colonization can begin anew.

In the long run, this plastic garbage will rub up against other debris or be broken by wave action. The plastic pieces get smaller and smaller. A ruby-red bottle cap might be scooped up by an albatross to be fed to its chick or the plastic rings holding a six-pack together might end up around a sea turtle, restricting normal shell growth. Captain Moore mentioned myctophids, an abundant group of lantern fishes which are a vital part of the open ocean food web. Dissections of their stomachs show some of these fish are eating as much plastic as food. Even the tiniest pieces can be ingested by filter feeders.

Plastics are known to absorb pollutants. Species low on the food web eat plastic scraps, creating another way for pollutants to end up in our food. I wonder, what that tuna I ate for lunch ate for its lunch?

So what can we do? I try to use as little as plastic as possible. I have my own metal water bottle and ceramic coffee cup. I keep food in glass containers, and use re-fillable bottles for shampoo and cleaning products. Any other ideas?

as a tangent: thanks to my husband for helping me with this one.

Down on the beach

Breaking waves on a sandy beach

I took a group of students down to a local beach last week – it turned out to be the only day that week that poured rain (I often have that kind of luck). As the students were doing their work, I walked up and down the beach to check on them. Since I was dressed for the rain I didn't mind the weather, in fact I found it pleasant to be away from my computer for a few hours. In addition to my rain jacket, I wore my rubber boots so I could walk through the shallowest waves and feel their strength tugging at my ankles. Okay, the real reason I wore my rubber boots was because they were dirty and I hoped the wave action would clean them.

Most of the beach was cobble, that is, composed of golfball to baseball sized smooth stones. With each step shifting rocks allowed my foot to sink in a bit, it almost felt like I was wading. Off shore, breaking waves (less than 1 metre) formed perfect curls along their tops before crashing down. Beneath the crashing waves, rocks tumbled with the moving water adding their own sound to that of the waves. Constant wave action was moving the rocky beach, in fact, all beaches exist in a constant state of change. At different time of year a beach may look completely different. In summer, gentle waves bring more sand on shore while in the winter, larger waves can remove the sand entirely.

Beaches are made from loose sediments like rock and sand or even ground up hardened lava (Hawaii has beaches like this) that are deposited. A sheltered place in between headlands is ideal as the headlands will take the brunt of wave energy. Beach sediments can originate from a far off river or from right close by. The cliffs overlooking the beach I was on provided all the sediments needed for the beach to form.

As a tangent – my rubber boots are now nice and clean.