THE LABRADOR CURRENT NEWFOUNDLAND – SECONDARY
The Labrador Current
Lesson Overview:
The main points covered in this lesson are the characteristics of the Labrador Current and:
§ The importance to fish and other marine species
§ Its climate influences on coastal areas
§ Influences of climate variation and change in the Arctic
§ Significance to Newfoundland and Labrador
Grade Level:
Grades 9-12
Time Required:
Two classes maximum
Curriculum Connection (Province and course):
Atlantic Provinces Education Foundation curriculum for Social Studies
People, Place and Environment General Curriculum Outcome:
Students will be expected to demonstrate an understanding of the interactions among people, places and the environment
Grades 10-12, Newfoundland and Labrador, Canadian Geography 1202
GCO 2.1.1: Basic patterns of land and water forms, which comprise the landscape of Canada.
GCO 2.1.2: Elements of weather and climate and how they account for diverse climate patterns in Canada.
GCO 2.1.3: Natural interrelationships in selected Canadian ecosystems and how they are typical of a northern environment.
GCO 2.1.5: Activities and issues related to how Canadians use resources in the ocean environment.
GCO: 2.2.1: Retrieving information from a variety of information-access tools, such as maps, globes, databases, newspapers, periodicals, videotapes and graphics.
GCO 2.2.3: Convergent and divergent thinking to develop spatial and temporal patterns in geographic phenomena.
GCO 2.2.6: Organizing information according to an acceptable format.
Links to Canadian National Geography Standards:
Essential Element #1: The World in Spatial Terms
Study of the Labrador Current involves linkage to its spatial position, involving usage of maps/globe/ atlas. Conic projections are appropriate here. Location of coastal communities with respect to the current, and allocation of marine resources can also be discussed.
Essential Element #2: Places and Regions
The Labrador Current is the dominant physical factor shaping coastal Labrador and northeastern Newfoundland. Its interaction with the Gulf Stream over the Grand Banks has provided the basis for the fishery that sustained much of Newfoundland and impacted all societies around the North Atlantic Ocean, in a mutually interdependent manner, for more than 500 years. The Labrador Current shapes the social and cultural identity of all the communities from Iqaliut to Fortune. Changes in the fisheries associated with the Current, due both to human activity and climate variations, have had, and continue to have, significant socio-economic impacts. Study of the Labrador Current can involve analyses at local (community), regional (coastal Newfoundland & Labrador), national and Northern Hemispheric scales.
Essential Element #3: Physical Systems
The Labrador Current is a key component of the physical environment of eastern Canada. It is linked to the global ocean current system, which in turn is linked to atmospheric systems and climate. The Labrador Sea and Grand Banks are important and distinct biogeographical regions. The North Atlantic and Arctic Oscillations, analogous to El Niño in the Northern Hemisphere, influence it.
Essential Element #4: Human Systems
The Labrador Current influences the fishery-dependent communities of Newfoundland and Labrador. Its importance in the fishery trade throughout the northern North Atlantic is indicative of the concept of Global Economic Interdependence.
Essential Element #5: Environment and Society
The effect of climate change on the Labrador Current creates changes in the climate of the coastal communities and in marine habitats. Thus, it serves as an example of an effect on the human environment resulting from a change in the physical environment. Relationships can be drawn to sustainability concepts and resource management.
Essential Element #6: Uses of Geography
Study of the Labrador Current represents an example of the value of a regional analysis in the context of the North Atlantic region as a whole.
Geographic Skills: Asking Geographic Questions
Study of the Labrador Current involves asking geographic questions on a number of levels, from the purely descriptive and locational, through to questions of marine processes, effects of human activity (e.g. fisheries), the influence of natural and human-induced climate change and the response of the system, to questions concerning human and community response to and interaction with the natural environment. Answering the questions will require acquisition, organization and assessment of geographical information, including that presented in this lesson as well as information obtained from other sources.
Additional Resources, Materials and Equipment Required:
§ Pictures of icebergs
§ Atlases/maps normally used in class.
§ Additional resources could include: Detailed map of Labrador; Topographic map of NL; Bathymetric chart
Main Objective:
§ Understand the physical characteristics of the Labrador Current
§ Understand the interactions between the current and other elements of the physical environment
§ Understand the socio-economic and cultural significance of the Labrador Current
Learning Outcomes:
§ In addition to fulfilling the objectives above, students can apply the same analytical techniques to the understanding of the characteristics, impact, influences and significance of any other current worldwide;
§ Understanding the interplay between biophysical and socio-economic geographical concepts;
§ Understanding that the concepts presented in “Oceans for Life” can be applied to any marine environment.
The Lesson:
Introduction / In common with all ocean basins, the water of the northwestern North Atlantic circulates vigorously. The major influences driving surface currents include wind stresses and pressure gradients on the sea surface.
In the North Atlantic, the Gulf Stream is the best-defined and strongest current.
As the Gulf Stream proceeds across the North Atlantic, it branches into several currents. A main branch, the Norwegian Current, flows northwards along the western coasts of Ireland, Scotland and Norway.
As the Norwegian Current flows northward, it is gradually diverted to the west through the Barents Sea, and along the Kalaallit Nunaat (Greenland) coast. This water circulates along the eastern shore of Davis Strait and Baffin Bay, extending to approximately 75°N (an area referred to as “North Water”).
Augmented by cold, fresh water from glaciers in Kalaallit Nunaat, the flow returns southward along the Labrador and eastern Newfoundland coast as the Labrador Current. It continues southward along the Avalon Peninsula to the Grand Banks, where it interacts with the Gulf Stream. / Locate on map:
North Atlantic Ocean
Locate on map:
Route of Gulf Stream; offshore of Florida, North Carolina; south of Sable island; south of Grand Banks
Calculate how long would a water molecule take to travel from Miami to the Grand Banks in the Gulf Stream?
Locate on map: Ireland, Scotland, Norway, Barents Sea, Kalaallit Nunaat, Davis Strait, Baffin Bay
Locate on map:
Route of Labrador Current from Cape Chidley south to Grand Banks
Lesson Development / The Labrador Current is not the strongest, largest or fastest current in the world. It transports approximately 6 million cubic metres of water each second southward, approximately 10% of the volume of the Labrador Current. The fastest-flowing belt normally is between 10 and 20 km wide.
Part of the reason for the low velocity is the atmospheric low-pressure system situated over Baffin Bay and to the south of Kalaallit Nunaat (‘Icelandic Low’). As the Labrador Current is flowing south, away from the low-pressure system, it is working against the atmospheric pressure gradient.
The Low Pressure system is intensified in some years and weakened in others. This cyclic process is referred to as the ‘North Atlantic Oscillation’ (analogous to ‘El Niño/La Niña’ cycle). A positive NAO phase (strong pressure gradient) results in stronger northeasterly winds blowing onto the shore, and a weakening of the Labrador Current. We have been in a positive phase of the NAO cycle since the late 1980s.
Surface temperatures increase from north to south along the current. In August, the surface temperatures off Nain are typically 5-6ºC, increasing to 12-13°C off Cape Race. (“Cold water” from a faucet typically is 15-20ºC).
The amount of salt in ocean water is controlled by temperature. Cold water can hold less salt than warm water (as cold coffee holds less sugar than warm coffee). Typically, the Labrador Current has a salt content (‘salinity’) of 32 parts per thousand (i.e. 32 g of salt per kg of water). Biological productivity is enhanced in zones where cold currents (e.g. Labrador) meet warm currents (e.g. Gulf Stream, with a typical August temperature of 17°C on the Grand Banks). This meeting of the waters triggers large amounts of sinking and upwelling. This results in the distribution of nutrients throughout the water column over the shallow Banks and Flemish Cap, and is the primary factor that made these areas among the richest fishing grounds in the world.
Sea ice reaches maximum extent and thickness in early February, more than 1000 km seaward of Nain and Hebron.
During the spring, the ice in the north retreats towards the land, but the ice extends further southward at the same time. In late March, sea ice extends more than 800 km offshore of Hopedale and Makkovik.
Approximately 2000 icebergs pass Cape Chidley each year. The number has been increasing slowly due to the gradual melting of glaciers on Baffin Island and Kalaallit Nunaat.
Ongoing climate change is melting the glaciers of Kalaallit Nunaat. This feeds more icebergs and cold water into the Labrador Current, causing it to get colder. Thus, one of the effects of ‘global warming’ is to make the Labrador Current colder and less saline, and to produce more icebergs and temporary sea ice along the coastlines of Labrador and northeastern Newfoundland.
Prevailing winds along the Labrador and Newfoundland coastline are westerly (from the southwest). As the winds in Labrador are blowing from land to water, the result is to bring dry air from the interior of North America to the Labrador coastline. Thus, the influence of the Labrador Current on coastal climate in Labrador is limited to the fringe of the shoreline.
The effect of the cool Labrador Current adjacent to the coastline results in cooling of exposed coastal areas. There are local differences in ‘continentality’ between exposed coastal sites (e.g. Battle Harbour) and more sheltered sites (e.g. Port Hope Simpson).
The effect of the North Atlantic Oscillation (NAO) is to intensify the seasonal differences during positive phases. This means that northeasterly winds (blowing from water to land) are stronger, leading to increases in wave height and coastal storms.
Climate Change, changing water temperatures, will influence these fish and mammal populations primarily by changing the distribution of the species that they need for food. Seals will be less affected than will whales and the walrus. / Calculate how long it takes a water molecule to travel from Nain to Cape St. Francis along the Labrador Current.
Speculate how variations from year to year could affect the Labrador Current.
Add salt to 1 litre of water. Continue to add salt until no more salt dissolves. Compare the mass of salt that can be added to cold water with the amount that will dissolve in warm water.
Locate on map:
Cape Chidley, Hebron, Nain, Hopedale Makkovik
If the sea ice were to leave northern Labrador earlier in the summer, what would be the effect on the coastline? What changes would people in the area notice? How would this change their lives?
Lesson Development / Nunaat.
Ongoing climate change is melting the glaciers of Kalaallit Nunaat. This feeds more icebergs and cold water into the Labrador Current, causing it to get colder. Thus, one of the effects of global warming is to make the Labrador Current colder and less saline, and to produce more icebergs and temporary sea ice along the coastlines of Labrador and northeastern Newfoundland.
Prevailing winds along the Labrador and Newfoundland coastline are westerly (from the southwest). As the winds in Labrador are blowing from land to water, the result is to bring dry air from the interior of North America to the Labrador coastline. Thus, the influence of the Labrador Current on coastal climate in Labrador is limited to the fringe of the shoreline.
The effect of the cool Labrador Current adjacent to the coastline results in cooling of exposed coastal areas. There are local differences in ‘continentality’ between exposed coastal sites (e.g. Battle Harbour) and more sheltered sites (e.g. Port Hope Simpson).
The effect of the North Atlantic Oscillation (NAO) is to intensify the seasonal differences during positive phases. This means that northeasterly winds (blowing from water to land) are stronger, leading to increases in wave height and coastal storms.
Climate Change, changing water temperatures, will influence these fish and mammal populations primarily by changing the distribution of the species that they need for food. Seals will be less affected than will whales and the walrus. / Look at photographs of icebergs.
For what can icebergs be used?
Should icebergs be used for economic purposes, or should they be left for tourists to look at?
How long does it take to melt an ice cube in tap water?
Study a map of NL. Explain how the prevailing winds, Torngat Mountains and Labrador Current combine to influence coastal Labrador’s climate?
On the island of Newfoundland, there are no large mountains to block the prevailing southwesterly winds; but northeasterly winds are more common. Does this allow the Labrador Current to influence coastal Newfoundland more than it influences coastal Labrador?
What impacts will changes in fish species have on the people?
What options are available for fishing communities, fish harvesters, fishing companies, and government managers of these fisheries?
Which species will benefit from climate change? Which will be adversely affected?
Look at water depths on a bathymetric chart
What could be the effects on particular whale species or on walrus?
Conclusion / Summarize key points.
Initiate discussion of the importance of marine resources to the communities, and to the region (and wider areas)
Initiate discussion as to the relative importance of climate and human activities on the fisheries of the Labrador Current / Discussion of any of the above points; or of the points listed in the Conclusions
Lesson Extension:
§ Any of the concepts presented here can be discussed in further detail, emphasizing local circumstances or going into greater depth.
§ Research the history of Battle Harbour; Black Tickle; Mary’s Harbour; St. Lewis; or other Labrador coastal community where ‘transhumance’ occurred
§ Can you think of any other types of communities where ‘transhumance’ was a feature of life in the historical past?