Behavior of Cetaceans in Response to Salinity in Maryland and Greenland

Having spent my whole life in Maryland, I know very little about narwhals or Greenland. When presented a figure of the distribution of 12 tracked narwhals (Figure 1), I noticed that these mammals spent the majority of their time away from the mouth of the fjord (Heide-Jørgensen et al., 2020), and that the fjord looked similar to the geography of the Chesapeake Bay in Maryland. To understand why the narwhals may prefer water near the tributaries to the fjord, I compared it to recorded locations of dolphins in the Chesapeake Bay.

Narwhals migrating through Lancaster Sound, Canada. Photo Credit: Paul Nicklen, https://paulnicklen.com/stills/narwhals/

            Data collected during a study on temperature-dependent habitat selection for narwhals displays 10 locations per day of 12 narwhals in Scoresby Sound in Greenland for a total of 1,000 positions (Heide-Jørgensen et al., 2020). The narwhals were tracked using satellite-linked time-depth recorders. The mapped positions of the narwhals (black dots) are more concentrated away from the mouth of the fjord complex where Atlantic water enters. Instead, they gather in tributaries on the western side of the fjord where there are active glaciers (red arrows).

Figure 1: Positions of 12 narwhals (black dots) tracked in Scoresby Sound fjord, Greenland. Positions were recorded 10 times per day, then resampled to 1,000 positions. Red arrows indicate active glaciers and yellow dots indicate positions where CTD profiles were collected (Heide-Jørgensen et al., 2020).

            The University of Maryland’s Chesapeake Dolphin Watch program (https://www.umces.edu/dolphinwatch) maps citizen dolphin sightings throughout the Chesapeake Bay. Figure 2 below displays the locations of dolphin sightings in 2017 (purple dots), 2018 (blue dots), and 2019 (orange dots). The figure also divides the bay into the upper bay, middle bay, and lower bay, with the lower bay closest to the Atlantic Ocean (Rodriguez et al., 2021). Within these divides, the majority of dolphin sightings are recorded in the upper bay, and overall more dolphins were sighted on the western side of the bay. The dolphin sighting distribution in the Chesapeake Bay in 2017-2019 resembles narwhal distribution in Scoresby Sound, Greenland. Both dolphins and narwhals appear to be found away from the mouth and instead in the tributaries.

Figure 2: Dolphin sightings in the Chesapeake Bay in 2017 (purple dots), 2018 (blue dots), and 2019 (orange dots). The bay is divided into upper, middle, and lower sections with the lower section being closest to the Atlantic Ocean (Rodriguez et al., 2021).

            Because of my familiarity with the Chesapeake Bay, I know that fresh water enters the bay from the tributaries and meets with salty water that enters from the Atlantic Ocean, which can be confirmed with salinity data available from the Chesapeake Bay Program (Reynolds, 2019). Applying this understanding to the Scoresby Sound, salinity is lowest where fresh glacial melt enters the fjord from the tributaries, as marked by red arrows in Figure 1, and salinity is highest where salty ocean water at enters the fjord at the mouth. Because the distribution of dolphins in the Chesapeake and narwhals in Scoresby Sound appear similar, and the bay and fjord have a similar pattern of salinity, I hypothesize that narwhals and dolphins prefer low salinity water.

Bottlenose dolphins in the Potomac River, a tributary of the Chesapeake Bay. Photo Credit: Ann-Marie Jacoby, Potomac-Chesapeake Dolphin Project, https://potomac.org/blog/2021/10/4/dolphin-disease-blog

            However, while the narwhals in Scoresby Sound were tracked using satellite-linked time-depth recorders, the dolphins in the Chesapeake are mapped from civilian sightings. In Maryland, most people that live along the Chesapeake Bay live in cities and suburbs along the western shore of the Bay (U.S. Census Data from 2020, https://www.census.gov/data.html). Of the approximate 986,305 people that live along the western shore, there were 90 dolphin sightings in 2017, or about 0.912 dolphins per 10,000 people. Fewer people live on the eastern shore of the Chesapeake Bay, and of the approximate 244,798 people, 29 dolphin sightings were reported in 2017, or about 1.18 dolphins per 10,000 people. From this data, more dolphin locations were recorded on the western shore of the Chesapeake Bay as a result of more people living there.

            Due to sampling bias, this citizen sighting data from the Chesapeake DolphinWatch program cannot be used to support the hypothesis that dolphins and narwhals tend to stay away from incoming salty water from the ocean because they prefer low salinity water. To better test the hypothesis, more accurate data of dolphin positions in the Chesapeake Bay would need to found by using satellite tracking devices similar to the ones used on the narwhals in Scoresby Sound.

Editor’s Note: Ms. Eleanor Smith wrote this essay as an extra-curricular activity developed from a science communication assignment for MAST383 – Introduction to Ocean Sciences. The editor teaches this course at the University of Delaware and was assisted by Ms. Terri Gillespie in a final formal edit.

References

Exchange for Local Observations and Knowledge of the Arctic. (n.d.). About Narwhals. Retrieved from ELOKA: https://eloka-arctic.org/communities/narwhal/about_narwhals.html

Heide-Jørgensen, MP, Blackwell, SB, Williams, TM, et al.: Some like it cold: Temperature-dependent habitat selection by narwhals. Ecol Evol. 2020; 10: 8073– 8090. https://doi.org/10.1002/ece3.6464, 2020.

Reynolds, D.: Bay health impacted by record flows. Chesapeake Bay Program, https://www.chesapeakebay.net/news/blog/bay-health-impacted-by-record-flows, 2019.

Rodriguez LK, Fandel AD, Colbert BR, Testa JC, Bailey H.: Spatial and temporal variation in the occurrence of bottlenose dolphins in the Chesapeake Bay, USA, using citizen science sighting data. PLoS ONE 16(5): e0251637. https://doi.org/10.1371/journal.pone.0251637, 2021.

Greenland Glacier-Driven Ocean Circulation

Greenland’s coastal glaciers melt, shrink, and add to globally rising sealevel. They also drive local ocean currents that move icebergs around unless they are stuck on the bottom. The glaciers’ melt is cold fresh water while the adjacent ocean is both salty and warm. Checking on what we may expect against observations, I here use data from NASA’s Ocean Melts Greenland initiative that dropped ocean probes from an airplane into the ice waters off coastal Greenland to measure ocean temperature and salinity.

For six years these data show how the coastal ocean off Greenland varies from location to location next to glaciers as well as from year to year. More specifically, I picked Melville Bay in North-West Greenland for both its many glaciers and many dropped NASA ocean sensors. The ocean data allow me to estimate ocean currents by using a 100 year old physics method. I just taught this to a small class of undergraduate science students at the University of Delaware. My students are strong in biology, but weak on ocean physics. This essay is for them.

Melville Bay is a coastal area off north-west Greenland between the town of Upernavik (Kalaallisut in Greenlandic) near 73 N latitude where 1100 people live and the village of Savissivik (Havighivik in Inuktun) at 76 N latitude where 60 Inuit live. There are no other towns or settlements between these two villages that are about as far apart as Boston is from Philadelphia, PA. Imagine there were no roads from Boston to New York to Philadelphia but only one large glacier next to another large glacier. This is Melville Bay.

Below I show an excellent set of photos of Savissivik by a French husband and wife team who visited in 2013/14. Their photographic gallery captures elements of contemporary subsistence living in remote Greenland where animals like seals, birds, fish, narwhal, and polar bears provide food, fuel, clothing, and income.

NASA dropped some 50 ocean sensors into Melville Bay froma plane during the short summer seasons each year 2016 through 2021. I met NASA pilots, engineers, and scientists doing their experiments when I was doing mine from a snowmobile in April of 2017 and again with Danish friends from a Navy ship in August of 2021, but these are stories for another day.

Let me start with a map of where NASA dropped their ocean profiling floats into Melville Bay and thus introduce the data. While the surface waters are usually near the freezing point, waters 300-400 meters deep down are much warmer. They originate from the Atlantic Ocean to the south and one of the goals of NASA’s “Ocean Melts Greenland” campaigns was to determine if and how these Atlantic waters reach the coastal glaciers. Most glaciers of Melville extend into this warm ocean layer and thus are melted by the ocean.

In the map above I paint the maximal temperatures in red and the bottom depths in blue tones. The profile on the right shows data for all depths at one station. As salinity increases uniformly (red curve) the temperature increases to a maximum near 300-m depth (black curve). It is this maximal subsurface temperature that I extract for each station and then put on the contour and station map on the left. The straight blue line connects Upernavik in the south with Sassivik in the north. It is an arbitrary line, coast-to-coast cutting across Melville Bay.

The warmest warm waters we find near Upernavik in the south and within a broad submarine canyon that brings even warmer waters from Baffin Bay towards the coast. Temperatures here exceed 2.4 or even 2.7 degrees Celsius. Most coastal waters along Melville Bay have a temperature maximum of about 1.5 to 1.8 degrees Celcius (about 35 Fahrenheit) and this “warm Atlantic” ocean water melts the coastal glaciers. The ocean melts the glaciers summer and winter while the warm air melts it only in summer.

There is more, because the glaciers’ melt also discharge fresh water into the ocean where it mixes to to form a layer of less dense or buoyant water. The buoyant waters create a local sealevel that is a little higher along the coast than farther offshore. The map above indicates that this “little higher sealevel” comes to about 4 cm or 2 inches. If this pressure difference across the shore is balanced by the Coriolis force, as it often does, then an along-shore coastal current results. This coastal current would move all icebergs from south to north unless they get stuck on the bottom. Along the northern coastline of Melville Bay the surface flow is from east to west. The coastal current is strongest near Savissivik where we find a (geostrophic) surface current larger than 40 cm/s. At that speed an iceberg would move more than 21 miles per day. Such strong surface flows are exceptional and diminish rapidly with depth. Hence a freely floating iceberg with a draft of several hundred meters would move much slower than the surface current.

I met a hunter from Savissivik in April of 2017 and for a fast-moving night we discussed the state of local fishing, hunting, living, traveling, and working on the sea ice next to the glaciers of Melville Bay. He invited me to become his apprentice. As such I would now ask him about the surface currents outside his home. Which way does he observe the icebergs to move in summer or winter? Has hunting on the sea ice in winter changed over his life time? When is it safe to travel there with a dog-sled? Could he and I perhaps work together during the spring to deploy ocean sensors through the sea ice? I am dreaming again …

Adaptations of Genetically Isolated Polar Bears in Southeast Greenland

Ms. Amanda Winton wrote this essay as an extra-curricular activity developed from a science communication assignment for MAST383 – Introduction to Ocean Sciences. The editor teaches this course at the University of Delaware and was assisted by Ms. Terri Gillespie in a final formal edit. ~Editor

“… The intense winds blow against my white fur. The chunks of white, frosty glacial ice float below me. I lift my eyes, scanning my surroundings for my next meal. I see a dark gray mass sliding along the ice a few hundred feet away. My mouth waters as my paws ready for the hunt. I have not eaten, nor seen any prey, in 12 days. I begin my slow and steady pursuit. The terrain below me is rough, unlike the abundant flat sea ice that was my ancestors’ hunting grounds.

It is a little bit more difficult to maneuver, taking more time to get to my prey than I would have hoped. Minutes later, I jump into the water, about to swim to the ice my prey is lounging on. Unfortunately, I grossly underestimated how far away it is, and by the time I swim to this meal, it’s gone. Now I am left with no food, and my stomach grumbles for the fifth time today.”

This short, first-person narrative is written from the perspective of a Greenland polar bear in the summertime. In particular, this polar bear is part of a subpopulation that hunts on a glacial mélange within fjords, rather than on larger frozen ice caps. Of course, I do not know what polar bears think in their pursuits, migration, or other actions. I can only use my own experiences and compassion to imagine their point of view and desires. Based on my biocentric view, all animals have their own importance in the world and are worthy of preservation. Since human intervention causes polar bears to struggle in their own environment, people have the responsibility to save them and recover their habitat.

Figure 1. This depicts the types of glaciers that can be present in different places, depending on the snow and ice available as well as the pressure and heat present. [adapted from National Snow and Ice Data Center]

Polar bears are losing their land due to the indirect and direct effects of human interaction with the environment, called climate change. Atmospheric warming leads to scarce and thinner glaciers, as well as less advancement in the growth season. The breakup of ice in the spring due to melting occurs nine days earlier than it did before global warming was identified in 1938 (Maslin, 2016), and the freezing of ice in the fall occurs ten days later (EPA, 2022). Not only is there less ice, but the ice exists for a shorter period of time. This leads to less territory, which can be detrimental to any species.

When Glacier National Park in Montana was established in 1910, about 150 glaciers existed. Now, less than 30 remain (Glick, 2021). Polar bears are forced to look for land and food elsewhere because they do not have as much space to hunt and breed. There is not much land or food present, so the natural selection rate for this animal is increasing dramatically every day, at a rate as fast as climate change (Peacock, 2022). Polar bears are forced by their environment to either die or adapt. This is not an easy adaptation, either.

Polar bears are forced to adapt quickly, since glacier ice is very limited in the Arctic. On the southeast coast of Greenland, polar bears have implemented a new habitat: fjords. These bears live at the front of glaciers in fjords, called the glacial mélange, which is a mixture of sea ice, icebergs, and snow. Only polar bears in southeast Greenland live there all year round, using this habitat to breed, hunt, and sleep.

Figure 2. This Glacier-Ocean-Mélange System depicts the forces acting upon this mechanism at all times. These forces are important for keeping the system at equilibrium and habitable for polar bears. [adapted from Amundson et al. (2020)]

In a recent research study led by Kristin Laidre, Northeast and Southeast Greenland polar bear population migrations were tracked. The median distance of the polar bears in the northeast was 40km per four days. The median distance traveled for the southeast population was 10km per four days, which is statistically significantly lower. Laidre et al. (2022) found that the southeast polar bears traveled between neighboring fjords, or stayed in the same fjord all year. This adaptation shows behavioral plasticity (Peacock, 2022), as Southeast Greenland bears have not become locally extinct.

This subpopulation of polar bears is one out of 20, and is very small. They are smaller in size and have a slower reproduction rate, most likely due to trouble finding a mate in a small population, as well as their long generation time and low natality. It’s important to preserve this genetically isolated population to preserve their genetic diversity. Without this element, birth defects, either mental or physical, will occur. This leads to a population less fit for its environment. Genetic diversity is necessary for surviving natural selection and thriving in an ecosystem. 

Figure 3. This photograph presents polar bears walking in the snowy fjords. Fjords are not flat, which makes it harder for these bears to travel, versus the flat ice that other polar bears have been hunting on for centuries. [adapted from Laidre et al. 2022]

“… I leave my fjord the next day, hoping to find another nearby, hopefully unoccupied. To my luck, one appears in my field of vision a few hundred meters away. To my surprise, a bob of seals rests on the glacial mélange. They are oblivious and unsuspecting of my presence. Minutes pass, and my stomach no longer rumbles. A successful hunt is always satisfactory. Now I can focus on my next need: my desire to find a mate and pass on my strong genes. It will not be too hard for me as I am a big male, with thick, insulated fur. I advance through the neighboring fjord, hopeful and confident. My story is just beginning.”

References:

Amundson, J., Kienholz, C., Hager, A., Jackson, R., Motyka, R., Nash, J., Sutherland, D., 2020: Formation, flow and break-up of ephemeral ice mélange at LeConte Glacier and Bay, Alaska. Journal of Glaciology, 66(258), 577-590. doi:10.1017/jog.2020.29.

Environmental Protection Agency, 2022: Climate Change Indicators: Arctic Sea Ice, https://www.epa.gov/climate-indicators/climate-change-indicators-arctic-sea-ice.

Dunham, W., 2022: Isolated Greenland Polar Bear Population Adapts to Climate Change. Reuters, Thomson Reuters, https://www.reuters.com/business/environment/isolated-greenland-polar-bear-population-adapts-climate-change-2022-06-16.

Glick, D., 2021: The Big Thaw. National Geographic, https://www.nationalgeographic.com/environment/article/big-thaw.

Greenfieldboyce, N., 2022: In a Place with Little Sea Ice, Polar Bears Have Found Another Way to Hunt, KTOO, https://www.ktoo.org/2022/06/20/in-a-place-with-little-sea-ice-polar-bears-have-found-another-way-to-hunt/.

Laidre, K. L. and 18 others, 2022: Glacial Ice Supports a Distinct and Undocumented Polar Bear Subpopulation Persisting in Late 21st-Century Sea-Ice Conditions, vol. 376(6599), 1333–1338, https://doi.org/10.1126/science.abk2793.

Maslin, M. , 2016: Forty years of linking orbits to ice ages, Nature, 540, 208–209, https://doi.org/10.1038/540208a.

Ogasa, N., 2022: Some Polar Bears in Greenland Survive on Surprisingly Little Sea Ice, Science News, https://www.sciencenews.org/article/polar-bear-greeland-sea-ice-glacial-melange-climate-change.

Peacock, E., 2022: A new polar bear Population, Science, vol. 376(6599), 1267–1268, https://doi.org/10.1126/science.abq5267.

National Snow and Ice Data Center, 2022: Glaciers, https://nsidc.org/learn/parts-cryosphere/glaciers/science-glaciers.

My own private Iceland

Reading Halldor Laxness’ epic novel “Independent People,” I am in Iceland for the last 10 days. I re-discovered this author after reading a small essay the New Yorker published last week. This book is set in Iceland of the early 1900s to the mid 1920ies. Sheep, starvation, and spirits evil and otherwise all play roles as does time that changes people, politics, and procreation. Finishing it sunday, I feel I have been here before.

Lifted from fioncchu,blogspot.com

My first Laxness novel “Islandklukken” (Iceland’s Bell in English) I read as a 20-year old during the Cold War when I served my country for 16 month more than 40 years ago. At the time I dreamt of the world as it had not yet revealed itself to me. My pre-college mind had a romantic notion of walking remote and wild areas of Norway and Iceland after an unromantic 1981 motorcycle trip across southern Norway the prior summer. I now worked as a paramedic in the drizzly gray German town of Husum by the North Sea. During this first winter away from parents and High School friends I bought my first Laxness and immediate afterwards “Die Saga von Egil” (Egil Skallagrimsson Saga). This Icelandic saga was written about 1200 AD and it chronicles the life of a viking poet farmer who killed many men for the 91 years after his birth in 904 AD. Along with this book I also bought a topographic map of Iceland published by the Touring Club of Iceland at a scale of 1:750,000 printed in 1979 in Reykjavik. It cost me 29.90 Deutsche Mark or about 10% of my monthly income at the time. Such armed, I followed Egil Skallagrimsson across Iceland starting at his place of birth about 35 miles north of Reykjavik.


Oil on canvas: “Summer in the Greenland coast circa the year 1000” painted by Danish painter Carl Rasmussen in 1874.

The same map follows me on my current travels across Iceland until I find the many databases of the Icelandic Geodedic Survey. High-resolution (1:50,000 scale, say) are generated instantly whereever I want. For days now I am hiking for days across the Icelandic highlands in the East and West, across interior deserts in the center, and wet coasts in the North. My first trip was across the Highlands from Pingvellir to Reykir past the glacier Langjoekull to the North and West and the glacier Hofsjoekull in the East and South. My maps locate many backcountry huts where I stay or pitch my tent. I here follow Dieter Graser’s excellent descriptions, photos, and GPS waypoints when he hiked the “Kjalvegur” alone in 2007. I even stole this map from his content-rich web-site where I spent the last 2 days traveling with finger on maps, books, and internets

Dieter Graser’s hike from Pingvellir in the south-west to Maellfell near Reykir in the north-east. It took him 19 days to complete this hike in August of 2007. [Credit Dieter Graser]

I even got a first intinary: My direct Iceland Air flight leaves Baltimore on Aug.-16 at 8:30 pm in the evening and arrives in Reykjavik the next morning at 6:25 am. A Grey Line bus gets me into the Highland for less than $48 in 2 1/2 hours, but it does not leave until 8 am on the next day. Hence there is plenty of time in iceland’s capital city to explore, get provisions, and perhaps visit the Landsbjoerg which is Iceland’s Search and Rescue organization. It is good practice to let someone local know when you will be where and back as one heads into the backcountry. The bus will let me off in Hviternes from where it is a 40 km hike to Hveravellir where there are two web-cams: the first points to the West while the second points East. I got 5 days to do this 3-day hike, so there is time for a day or two to do nothing, read, or just soak in the scenery and/or a hot spring and/or both at the same time. The bus will pick me up at the hot springs of Hveravellir at 2:30 pm on Aug.-22 to get me back to Reykjavik at 7:30 pm which is plenty of time to catch my plane back home the next day at 5:10 pm with an arrival 6 hours later. The return flight comes to $746 and even includes my backpack (<50 lbs).

There is just one problem … my passport expired.

P.S.: The three photos below are all from Dieter Graser who shared them at his outstanding web-site at http://www.isafold.de/

The hut Þverbrekknamúli along the “Kjalvegur.” The view is to the east with the Kerlingarfjöll in the back. [Credit Dieter Graser]
Dieter Graser at Hvítárnes in 2007. [Credit Dieter Graser].
Hveravellir in August 2007. [Credit Dieter Graser]

Ice, ocean, and glacier change in northern Greenland

Steffen Olsen is a Danish physical oceanographer with a skill to present beauty to an artist like my wife and a scientist like me. Three days ago he posted a photo on Twitter with these words

Local hunters from Qaanaaq navigating our CTD system in the frozen ice mélange in front of Tracy Galcier 66W 77N to measure the ocean below. Heat loss to melting of glacial ice leaves the ocean at sub-zero temperatures down to 400m @arctic_passion @dmidk @ruth_mottram

Photo: Dogsled from Qaanaaq near the northern edge of Tracy Gletscher in Inglefield Fjord April 2022. [Credit: Dr. Steffen Olsen, Danish Meteorological Institute.]

Steffen’s photo shows his study area, research platform, and mode of transportation. There is a glacier in the background between the rocks on the left (north) and unseen mountains to the right (south). Equally unseen is the ocean under all this crushed and broken and piled up sea ice covered by fresh snow. We see tracks of people walking to the vantage point from where the photo is taken. The dogs rest on a small patch of level sea ice perhaps 3-5 feet (1 to 1.5 meters) thick.

There are boxes on the sled that contain gear to drill through the sea ice and then to send a probe down towards the ocean bottom to measure ocean temperature, saltiness, and oxygen during its decent. I did similar work with a snowmobile in 2017 based at Thule Air Base for 6 weeks. Steffen and I work together on such data. He collected these every year since 2011 both adjacent to Tracy Gletscher and along most of the ~120 km long and ~1000 meter deep fjord. I am grateful to Steffen to share this photo: It helps me to focus on my passions rather than my outrage at soldiers and leaders of the Russian Federation in their war to destroy Ukraine and its people building a free, vibrant, and democratic country for themselves. There is more, but I stop here now.

Let me start with a map of where in Greenland the photo was taken and where Steffen collected his data each since 2011. The red star in the insert top-right shows the location of the map between Canada and Greenland. I color ocean bottom depths in blue shades and land heights in green, yellow, and brown shades. The glacier in Steffen’s photo is at the north-eastern end of Inglefield Fjord where I placed the label Tracy. The label Qaanaaq shows where about 650 Inughuit live along the coast near the center of the fjord. It probaby took the dogs about 2-3 days to travel with their cargo from Qaanaaq to Tracy Gletscher. Red dots are stations served by a Danish Navy ship in the summer of 2015, but I here only talk about the blue dots.

Figure: Map of the study area with ocean sampling stations in Inglefield Fjord (blue dots) and adjacent northern Baffin Bay. [Unpublished own work.]

The blue dots are stations where Steffen and his companions drilled through the sea ice in 2018. Note that some of those ocean stations appear on land. This cannot be, but the glacier has retreated between the time the topographic data was collected and 2018 when Steffen collected the ocean data. Three LandSat satellite images below show how the glacier changed from 1973 to July and August of 2021. Icebergs are visible, too. A citizen scientist with the handle “Espen” at the Arctic Sea Ice Forum extracted these satellite photos from public U.S. databases. He is part of an online international community of Greenland and sea ice enthusiasts who posts at this forum for over a decade making daily discovers. These are people with regular jobs that in their spare time post satellite imagery and open data they found which they share openly often with insightful interpretations. It is citizen science at its very best. I go there often to read, ask, and learn. I even met a prominent member once for lunch when visiting Copenhagen on my way to Greenland. He gifted me LandSat imagery of my favorite glaciers printed on cloth that I framed for its scientific and artistic beauty. Thank you, Espen 😉

Gallery: Space photography (LandSat) of glaciers terminating from the Greenland ice sheet in Inglefield Fjord in 1973 (right), July 2021 (center), and August 2021 showing the retreat of Tracy but not Heilprin Gletscher. [Credit: Espen Olsen at Arctic Sea Ice Forum.]

So how does the ocean below all this ice next to a glacier look? Well, lets look at a set of station from Qaanaaq to Tracy Gletscher that shows how temperature, salinity, and oxygen of the water changes both with depth and along the fjord. We always find very cold, somewhat fresher, and highly oxygenated water near the ocean surface about 40 m (near glacier) to 100 m (near Qaanaaq) below the sea ice and warmer, saltier, and less oxygenated water below with a temperature maximum of 1 degree Celsius near 300 m depth. It is this warm water that melts the adjacent glacier. As Dr. Olsen says “… Heat loss to melting of glacial ice leaves the ocean at sub-zero temperatures …” In other words, the deeper waters 1. enter the fjord at temperatures above zero degrees Centigrade, 2. reach the glacier, 3. cool down as they melt the glacier, and 4. leave the fjord at temperatures below zero degrees Centigrade. This is why the two stations near the glacier show slightly fresher and cooler waters between 300 and 500 m depth. This water contains the glacial melt. The section represents the 10 year average from 2011 through 2020.

Figure: Section of salinity (bottom), temperature (center), and dissolved oxygen (top) along Inglefield Fjord as an average of data collected annually between 2011 and 2020. [Unpublished own work.]

Earlier this year I tried to visit Copenhagen to finish this work that places this emerging story into both a historical and spatial context, but Covid restrictions derailed this and other plans. Nevertheless, have excellent data from 1928 when this fjord was first surveyed by Danish oceanographers. At that time the waters had dramatically different temperatures (much colder) and salinities (a little fresher) both inside the fjord and in Baffin Bay adjacent to it. The changes are probably related to a much changed sea ice cover and perhaps ocean circulation that relates how the winds impact the ocean with and without sea ice. For the 1979 to present satellite record, we can quantify how much sea ice covers both the fjord and adjacent ocean. I made the graph below last week from 14073 almost daily satellite images whose data the U.S. National Snow and Ice Data Center distributes freely. I show annual averages for each of the 42 years that these SSM/I satellites have been measuring sea areal coverage from space.

Figure: Annual averages of sea ice cover 1979 through 2021 with linear trend lines for two 21-year subsets (blue) and the entire 42-year record (red). [Unpublished own work.]

Before the year 2000 the sea ice cover fluctuated between 26,000 and 39,000 km2 and if one for how these changes are trending between 1979 and 2002, one finds a slight increase in the blue line, however, this increase is not significantly different from zero at a high 95% level of confidence. For the second period after 2002, the ice covered area fluctuates much less, from about 22,000 to 28,000 km2 and the trend line in blue now indicates decreasing sea ice cover. As before, however, this blue trend line is no different from zero at the same high level of confidence. We also notice that there is a red trend line that I derive from using all 42 years of data. This line is very different and statistically significant, but it does not quiet do justice to the almost step-like change that appears to happen around 2000 through 2005. What happened then? I do not know, yet, but this is the fun of doing science: There is always more to discover. The sea ice cover in northern Greenland does not always follow a straight line. This is not different from our climate or life. Expect the unexpected, adjust, and keep moving. Or in Dr. Olsen’s words:

“… you have a number of years where conditions don’t follow the more linear track of (predicted) scenarios,” explained Dr. Olsen. “A warming tendency can be reversed for some years, for example.” [From https://phys.org, Oct.-13, 2021]