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Labrador Current

The Labrador Current is a major cold-water boundary current in the North Atlantic Ocean, flowing southward from the Arctic along the eastern coast of Canada, transporting frigid, low-salinity waters that significantly influence regional climate, marine ecosystems, and global ocean circulation.^[1]^[2] Originating primarily from the Baffin Island Current and a branch of the West Greenland Current, the Labrador Current forms in Baffin Bay and merges on the western side of the Labrador Sea, carrying Arctic-influenced waters southward through Hudson Strait along the Labrador continental shelf and slope.^[3]^[4] It splits into an inshore branch that hugs the Newfoundland coast and an offshore branch that follows the edge of the Grand Banks, eventually retroflecting near 45°N where approximately 60% veers northeastward to join the North Atlantic Current, while the remainder continues westward or recirculates.^[1]^[4] Characterized by surface temperatures around -1.5°C and relatively low salinity compared to surrounding Atlantic waters, the current features a shallow shelf component (Labrador Shelf Water) that is the coldest and freshest, and a deeper slope branch (Labrador-Subarctic Slope Water) extending to about 2,500 meters, with total volume transport estimated at up to 40 Sverdrups for the broader subpolar gyre system.^[3]^[2] Its flow speed averages around 14-15 cm/s in the southeastern segments, and it interacts dynamically with the warmer Gulf Stream, creating sharp oceanographic fronts, fog-prone zones, and the transport of icebergs southward into "Iceberg Alley" near the Grand Banks.^[3]^[1] The Labrador Current plays a critical role in the Atlantic Meridional Overturning Circulation by exporting fresh, oxygenated waters that affect deep convection in the Labrador Sea and influence salinity anomalies across the subpolar North Atlantic, with variations linked to the North Atlantic Oscillation impacting nutrient distribution and fisheries productivity in the Northeast U.S. Shelf ecosystem.^[4]^[2] It also carries an average of about 479 icebergs annually into North Atlantic shipping lanes, posing navigational hazards while preserving Arctic climate signals that propagate southward.^[1]

Overview

Description

The Labrador Current is a cold, southward-flowing peripheral current of the North Atlantic subpolar gyre, originating from the Arctic Ocean via inflows through the Canadian Arctic Archipelago and Davis Strait.^[4] It forms a narrow boundary current along the continental shelf, primarily fed by the West Greenland Current and augmented by Arctic exports.^[5] This current plays a fundamental role in the regional ocean circulation by transporting cold, low-salinity water southward along the western boundary of the Labrador Sea, thereby influencing the distribution of freshwater and heat in the subpolar North Atlantic.^[6] Its southward advection helps maintain the salinity gradients essential for the basin's thermohaline dynamics.^[7] Within the broader Atlantic Meridional Overturning Circulation (AMOC), the Labrador Current serves as a key component of the upper limb, exporting relatively fresh, oxygenated waters southward that influence deep convection and the formation of dense waters in the subpolar region for the equatorward deep return flow.^[6] This positioning underscores its importance in the global thermohaline conveyor belt, where it facilitates the southward flux of relatively fresh, oxygenated waters.^[4]

Geographical Extent

The Labrador Current originates in the Davis Strait and Baffin Bay, where it forms from the merging of cold waters from the Baffin Island Current and a branch of the West Greenland Current near Hudson Strait on the western side of the Labrador Sea.^[3] It then flows southward along the Labrador coast, closely following the continental shelf and upper slope, with an inshore branch hugging the coastline and an offshore branch extending along the western boundary of the Labrador Sea.^[8] This path continues past the Grand Banks of Newfoundland, where the current broadens and interacts with the shelf topography, before reaching the Tail of the Grand Banks southeast of Newfoundland.^[9] The current maintains a width of approximately 100–200 km, centered primarily over the shelf break and extending seaward, which allows it to influence a significant portion of the continental margin along eastern Canada.^[3] Its proximity to the coast—often within 50–100 km offshore in the northern sections—directly affects the coastal regions of Labrador and Newfoundland by constraining warmer waters to the east and shaping local marine environments.^[8] Near 42°N latitude at the Tail of the Grand Banks, the Labrador Current begins to veer eastward, retroflecting and merging its waters with the warmer North Atlantic slope water, marking the transition from its dominant coastal southward flow to broader oceanic influences.^[9] This spatial extent contributes to cooling effects along the Atlantic provinces of Canada and the U.S. Northeast coast.^[3]

Physical Characteristics

Temperature and Salinity

The Labrador Current exhibits characteristically low temperatures, with surface waters typically ranging from 0°C to 5°C, reflecting its origin in cold polar regions. The core of the cold intermediate layer maintains temperatures below 0°C, typically around -1°C, while subsurface layers in the offshore slope branch can reach 3–4°C.^[10]^[11] The current consists of Labrador Shelf Water (coldest and freshest on the shelf) and Labrador Slope Water (warmer and more saline along the slope).^[3] Salinity in the Labrador Current is notably low, ranging from 31 to 34.5 practical salinity units (psu), primarily due to dilution by freshwater inputs that distinguish it as a low-density water mass relative to the surrounding North Atlantic waters, which often exceed 35 psu.^[11] This reduced salinity contributes to the current's overall buoyancy and influences regional density stratification. Seasonal variations are pronounced, with waters becoming cooler and saltier in winter—surface temperatures dropping to near -1.5°C—due to atmospheric cooling and brine rejection during sea ice formation, which increases surface salinity through salt expulsion.^[12]^[13] In contrast, summer conditions feature warmer surface temperatures up to 6–7°C and lower salinities from river runoff and ice melt, though the core remains cold. Vertically, the current displays a gradient with fresher, lighter surface layers overlying saltier, denser deep waters, enhancing baroclinic structure in the flow.^[12]

Velocity and Transport

The Labrador Current exhibits average surface velocities ranging from 20 to 50 cm/s (0.2 to 0.5 m/s), with measurements indicating typical values around 23–27 cm/s along its core path.^[9]^[14] In narrower channels, such as Flemish Pass, maximum speeds can reach up to 100 cm/s due to topographic constriction enhancing flow intensity.^[15] These velocities are primarily directed southward along the continental shelf break, though the current features prominent meanders and eddies that introduce variability in flow direction and contribute to offshore recirculation.^[9] The total volume transport of the Labrador Current is estimated at 5–10 Sverdrups (Sv), with specific sections showing values up to 10.7–11 Sv near Hamilton Bank.^[15]^[14]^[9] Transport exhibits seasonal variations, generally peaking in winter and reaching minima in spring, but with enhanced freshwater flux in summer attributable to meltwater inputs from Arctic and Greenland sources.^[15]^[16] The current's barotropic component allows southward flow to extend to depths of approximately 2500 m, comprising up to 65% of the total transport in shelf regions and facilitating deep western boundary current dynamics.^[9] Density-driven variations, arising from the current's cold, fresh characteristics, further modulate these velocities by influencing baroclinic shear.^[14]

Origin and Sources

Polar and Arctic Inputs

The Labrador Current receives its primary cold, saline inputs from the Arctic Ocean through the Davis Strait, where the Baffin Current exports a mixture of water masses originating from northern gateways. This outflow primarily carries Polar Surface Water (PSW), which enters Baffin Bay via Lancaster Sound (transport of 0.77–0.85 Sv) and Nares Strait (0.75–0.83 Sv), characterized by low salinities of 33.0–33.2 and undergoing transformation through sea ice formation into denser forms before southward export.^[17] Additionally, Arctic Intermediate Water contributes significantly, with deep inflows through Nares Strait (0.62 Sv) and the West Greenland Current (0.41–0.54 Sv) mixing in Baffin Bay and resulting in a net export of 0.34–0.65 Sv via Davis Strait, forming a key component of the Labrador Current's intermediate layer.^[17] A substantial contribution also arises from the West Greenland Current, which integrates polar waters by merging with the East Greenland Current around Cape Farewell at Greenland's southern tip. The East Greenland Current, transporting cold Arctic waters southward along Greenland's eastern coast, partially retroflects and combines with the East Greenland Coastal Current to form the shelf-based West Greenland Current system, carrying both Arctic-origin water and local influences northward before diverting southward to join the Labrador Current offshore.^[18] This merger enhances the polar signal in the Labrador Current's offshore branch, with the West Greenland Current contributing an estimated 0.4–0.5 Sv of intermediate water that mixes into the overall flow.^[17] The circulation within Baffin Bay plays a crucial role in conditioning these polar inputs, as cyclonic gyre dynamics mix Arctic inflows from the north with recirculating waters, producing relatively uniform cold characteristics in the exported Baffin Current. This Baffin Bay-influenced outflow through Davis Strait accounts for approximately 30–40% of the Labrador Current's total volume transport, based on typical Davis Strait exports of 1.5–2.0 Sv upper-layer water relative to the Labrador Current's overall 5–7 Sv.^[17]^[19] These inputs establish the current's core polar signature before further modifications occur downstream.

Freshwater Contributions

The Labrador Current receives substantial freshwater inputs primarily from Baffin Bay via Davis Strait and from Hudson Strait, which together account for a significant portion of its low-salinity characteristics. These inputs, derived from river runoff and glacial melt, contribute up to 50% of the total freshwater flux in the current, with Hudson Strait alone providing approximately 78–88 mSv of freshwater transport relative to a reference salinity of 34.8. River discharge into the Hudson Bay system totals around 900 km³ per year, while glacial melt and precipitation further dilute the waters entering through Hudson Strait. Similarly, Baffin Bay waters, influenced by Arctic river inputs and local glacial sources, flow southward through Davis Strait, enhancing the freshwater signal in the Labrador Current's coastal branch.^[20]^[21] Seasonal sea ice melt from the Arctic Ocean and Greenland's periphery adds low-salinity surface layers to the Labrador Current, particularly during late spring and summer when melting peaks. This meltwater, estimated at an additional 8 mSv from Arctic sea ice since the 1990s, originates from accelerated ice loss and is transported southward via the East Greenland Current before integrating into the Labrador system. Greenland ice sheet melt contributes another ~12 mSv of freshwater flux, which reaches the Labrador Sea within months and forms a buoyant cap over deeper waters, with peak effects observed in early summer on the Labrador shelf. These seasonal inputs create fresher surface waters that propagate downstream over approximately 180 days from Davis Strait to the Newfoundland shelf.^[22]^[21] Recent studies indicate continued increases in freshwater export, with projections of enhanced flux from Davis Strait at about 1.4 mSv per year over the 21st century due to anthropogenic warming, contributing to freshening events and potential weakening of Labrador Sea convection as of 2024.^[6]^[23] The cumulative freshwater from these sources reduces the overall density of the Labrador Current, enhancing its buoyancy and positioning it as a primary conduit for Arctic freshwater export to the subpolar North Atlantic. This export, totaling around 20 mSv of increased flux in recent decades, stabilizes the current's stratification and influences downstream salinity levels, typically maintaining surface values below 32 in the core flow. By transporting low-density water equatorward along the western North Atlantic boundary, the Labrador Current plays a critical role in modulating regional ocean circulation and heat exchange.^[22]^[24]

Path and Trajectory

Surface Flow Route

The Labrador Current originates in the Labrador Sea, where it forms from the confluence of cold waters from the Baffin Island Current and a branch of the West Greenland Current, primarily near the western side of the basin. From there, its surface flow proceeds southward along the western boundary of the Labrador Sea, hugging the continental slope and shelf break parallel to the Labrador coast. This coastal path maintains a relatively narrow corridor, typically within 50-100 km of the shoreline, as the current transports Arctic and subpolar waters equatorward.^[3] As it continues southward, the current skirts the eastern edge of Newfoundland, intensifying between the 200-2000 m isobaths upstream of Flemish Pass around 49°N, before extending along the outer shelf and slope of the Grand Banks. The flow remains coherent over this stretch, with the main axis centered near the shelf break, carrying significant volumes of cold, low-salinity water southward. Upon reaching the Grand Banks, the current begins to exhibit more variability, passing around the bank's periphery while some portions interact with the bathymetry to generate localized features. The typical surface speeds along this route range from 10 to 25 cm/s, averaging around 15 cm/s in southeastern segments, varying with seasonal and topographic influences.^[25]^[26] The surface trajectory culminates at the Tail of the Grand Banks near 42°N, approximately 50°W, where the current encounters a southeastward-extending ridge from the main bank plateau. Here, it undergoes initial mixing with warmer waters and begins to veer southeastward, transitioning toward broader North Atlantic circulation patterns. Along the entire path, the flow is characterized by meanders and eddies, particularly around topographic features like Hamilton Bank and Flemish Cap, which contribute to offshore dispersion. Notably, branches detach eastward toward the Flemish Cap (around 46°N, 45°W), where some water anticyclonically circulates before joining the subpolar front.^[25]^[27]

Vertical Structure

The Labrador Current exhibits a distinct vertical structure characterized by layered water masses with varying densities, leading to differential flow dynamics across depths. The surface layer, extending from the sea surface to approximately 200 m, consists of cold, fresher water primarily derived from Arctic and polar sources, which drives a buoyancy-dominated (baroclinic) flow with relatively weak vertical shear.^[28] This layer experiences high-frequency variability, with mean velocities around 0.125 m/s directed southward along the western boundary.^[28] Below the surface layer, the intermediate depths from about 200 m to 1500–2500 m encompass the Labrador Sea Water (LSW) layer (density σθ ≈ 27.68–27.80 kg/m³), where the flow transitions to a more uniform, pressure-driven (barotropic) character with minimal vertical shear.^[28] This layer carries denser, saltier water masses, contributing to a significant portion of the current's total transport, estimated at around 20 Sv.^[28] Deeper still, from 2500 m to the seafloor, the current incorporates overflow waters such as the Denmark Strait Overflow Water (DSOW), exhibiting renewed baroclinicity with peak velocities of up to 0.27 m/s near the bottom and strong density-driven shear.^[28] In the Labrador Sea, the current's vertical extent reaches up to 3000–3500 m, aligning with the basin's bathymetry, where the deep western boundary current (DWBC) component dominates the lower layers.^[29] Vertical shear between layers arises primarily from density gradients induced by temperature and salinity differences, with the fresher surface waters overlying saltier intermediate and deep waters.^[28] Overall, the structure reflects a hybrid baroclinic-barotropic regime, with baroclinicity prominent in the buoyant upper and dense deep layers, while barotropic flow prevails in the mid-depths.^[28]

Interactions

With Gulf Stream

The Labrador Current and the Gulf Stream converge at the Tail of the Bank, near the southeastern tip of the Grand Banks of Newfoundland, where the Shelf Break Front marks a critical transition zone along the continental shelf edge.^[30] This interaction creates a sharp thermal boundary approximately at 40°N latitude, separating the cold, fresh waters of the Labrador Current from the warm, saline waters of the Gulf Stream, with temperature contrasts often exceeding 10–15°C across the front.^[2] The boundary's position varies seasonally and interannually, influenced by Gulf Stream meanders and wind forcing, but it consistently delineates the northwestern limit of the subtropical gyre's influence.^[30] In the resulting frontal zone, intense mixing occurs through shear instabilities, generating a high density of mesoscale eddies—particularly anticyclonic eddies that increase by about 15% during periods of strong Labrador Current retroflection.^[30] This dynamic region facilitates cross-frontal exchange, with approximately 60% of the Labrador Current's transport retroflecting eastward along the Shelf Break Front rather than continuing southward.^[30] The mixing also drives persistent fog formation over the Grand Banks, as warm, moist air advected from the Gulf Stream condenses upon encountering the colder Labrador Current surface waters, creating one of the world's foggiest marine areas with visibility often reduced to less than 1 km.^[2]^[1] The reciprocal influences between the currents are profound: the Labrador Current cools the western edge of the Gulf Stream by entraining cold intermediate waters into its slope branch, reducing sea surface temperatures by up to 2–3°C locally, while the Gulf Stream warms the outer path of the Labrador Current through eddy shedding and heat flux, moderating its southward cooling effect on the shelf.^[30]^[2] These exchanges contribute to enhanced biological productivity in the frontal zone, supporting rich fishing grounds, though the details of marine life impacts are addressed elsewhere.^[2] Over recent decades, a northward shift in the Gulf Stream since around 2008 has intensified this retroflection, with a trend of +2.4% per decade in the retroflection index, altering salinity patterns in the adjacent Slope Sea and subpolar North Atlantic.^[30]

With North Atlantic Gyre

The Labrador Current, upon reaching the vicinity of the Grand Banks off Nova Scotia, undergoes partial retroflection, with a significant portion—approximately 60% of its transport—diverting eastward to integrate into the North Atlantic subpolar gyre.^[31] This retroflected branch feeds directly into the North Atlantic Current, enhancing its eastward flow across the basin and facilitating the gyre's counterclockwise circulation.^[3]^[31] Within the subpolar gyre, the Labrador Current plays a crucial role in closing the circulation loop by connecting the southward western boundary flow to the northward return pathways. Water influenced by the Labrador Current joins the North Atlantic Current and circulates through the Irminger Current toward the southwest coast of Greenland, before integrating into the East Greenland Current for southward transport along the eastern flank of the gyre.^[3] This connectivity ensures the gyre's integrity, with the overall subpolar gyre transport estimated at around 40 Sv.^[3] The current's integration into the gyre significantly influences the region's thermohaline balance by exporting cold, fresh water southward, which offsets the northward advection of warmer, saltier waters via the North Atlantic Current.^[3]^[24] This southward export, primarily through the deep western boundary current component, helps sustain the density-driven overturning by removing heat and excess salinity accumulated in the subpolar domain, with variations in retroflection strength altering gyre-wide salinity by up to 0.10 units.^[31]

Environmental Impacts

Iceberg Transport

The Labrador Current plays a critical role in the southward transport of icebergs calved from tidewater glaciers along the west coast of Greenland, carrying them through the North Atlantic shipping lanes and posing significant navigational hazards. Approximately 90% of these icebergs originate from western Greenland glaciers, where massive ice sheets calve into the ocean due to glacial dynamics. A prominent example is Jakobshavn Glacier (now officially Ilulissat Glacier), which annually releases around 20 billion tons of ice, with resulting bergs entering the Baffin Bay and subsequently being entrained by the current's surface flow.^[32]^[33] This transport occurs primarily during spring and early summer, when the current's offshore branch flows southward along the Labrador continental shelf, reaching the Grand Banks of Newfoundland after a journey of about 1,800 nautical miles that typically spans 2-3 years from calving. On average, around 400-800 icebergs per year enter the transatlantic shipping lanes south of 48°N, though numbers vary widely by season and year, with historical peaks exceeding 2,000 in exceptional cases like 1984. The peak influx happens between April and June, driven by seasonal strengthening of the current and reduced sea ice interference, funneling the bergs into "Iceberg Alley" off Newfoundland's coast.^[1]^[34]^[1] Oceanic eddies within the Labrador Current can occasionally divert icebergs from their primary southward trajectory, steering them eastward toward regions like the Azores or southward to Bermuda, thereby extending potential hazards beyond the typical Grand Banks area. These eddies form at the interface with warmer currents such as the Gulf Stream, capturing and redirecting bergs in rare instances, as documented in historical drift records. Such deviations, while infrequent, highlight the dynamic nature of the current's influence on iceberg distribution and maritime safety.^[32]^[35]

Climatic and Weather Effects

The Labrador Current transports cold Arctic waters southward along the eastern coast of Canada, exerting a significant cooling influence on the overlying atmosphere and contributing to lower air temperatures across eastern Canada and the northeastern United States. This cooling effect is particularly pronounced during winter, where the frigid surface waters enhance heat loss from the atmosphere to the ocean, resulting in colder winters in the Labrador region and adjacent areas.^[36]^[37] In summer, the current's cold waters interact with warmer, moist air masses advected from the south, promoting the formation of advection fog over the Grand Banks of Newfoundland. The Labrador Current maintains sea surface temperatures as low as 5–10°C in this region during the warmer months, causing the air to cool below its dew point and condense into fog, with occurrence rates peaking at around 45% in July and remaining high from May to August.^[38] The current facilitates intense air-sea interactions in the Labrador Sea, where strong upward heat fluxes—often exceeding 600 W m⁻² during winter storms—transfer energy from the ocean to the atmosphere, invigorating storm tracks across the North Atlantic. These enhanced fluxes contribute to the development and intensification of extratropical cyclones along the primary storm path, influencing precipitation patterns by increasing moisture availability and leading to higher rainfall in downstream regions such as western Europe and eastern North America.^[39]^[40] Through its transport of freshwater from Arctic sources, the Labrador Current can create a buoyant surface cap in the Labrador Sea, suppressing deep convection and potentially slowing the Atlantic Meridional Overturning Circulation (AMOC) by reducing the formation of dense Labrador Sea Water. This feedback mechanism may amplify North Atlantic weather variability, as a weakened AMOC diminishes poleward heat transport, leading to shifts in storminess and temperature extremes across the basin.^[22]

Ecological Role

Nutrient Distribution

The Labrador Current transports nutrient-rich waters originating from the Arctic southward along the eastern Canadian continental shelf, delivering elevated concentrations of nitrate, phosphate, and silicate to subarctic regions. These Arctic-sourced waters are characterized by high nutrient levels due to limited biological uptake in the cold, low-light environments of the Arctic Ocean, allowing the current to act as a conduit for nutrient export into the North Atlantic. As the current flows southward, it maintains these nutrient signatures, with typical winter concentrations of nitrate exceeding 10 μmol/L and phosphate around 0.8 μmol/L in the upper water column along the Newfoundland Shelf.^[41] Upwelling processes at the fronts of the Labrador Current further elevate nutrient availability, particularly phosphate and nitrate, by drawing deeper, nutrient-replete waters to the surface. These fronts form where the cold, dense Labrador Current interacts with adjacent warmer water masses, generating cyclonic eddies and vertical mixing that enhance nutrient fluxes to the euphotic zone. Such upwelling is most pronounced along the shelf break and over submarine banks, where topographic steering amplifies the supply of nutrients like nitrate (up to 15-20 μmol/L in upwelled parcels) and phosphate (0.9-1.2 μmol/L), supporting elevated primary production. Interaction-driven upwelling at the boundary with the Gulf Stream contributes to this nutrient elevation, as detailed in studies of their convergence. On the Grand Banks, the influx of cold, nutrient-laden Labrador Current waters mixes with warmer inflows from the Gulf Stream, fostering conditions for extensive phytoplankton blooms. This mixing stratifies the water column while injecting nutrients into sunlit surface layers, triggering rapid algal growth dominated by diatoms and coccolithophores. The enhanced nutrient availability from the Labrador Current sustains these blooms, which are visible as large chlorophyll patches in satellite imagery. Seasonal nutrient flux peaks in spring, coinciding with increasing daylight and shoaling of the mixed layer, leading to high biological productivity rates of approximately 193 g C m⁻² year⁻¹ across the Banks.^[42]^[43]^[44]

Influence on Marine Life

The Labrador Current's influx of cold, nutrient-rich waters to the Grand Banks fosters high primary productivity, underpinning a robust food web that sustains key commercial fisheries for Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), and capelin (Mallotus villosus). Capelin acts as a central forage species, converting planktonic production into energy for predatory fish like cod and haddock, thereby supporting predator biomass and fishery viability in this region. This nutrient-fueled dynamic has historically enabled substantial harvests, with capelin serving as a linchpin in the ecosystem's energy transfer from lower to higher trophic levels. As of 2025, the total allowable catch (TAC) for capelin in NAFO divisions 2J3KLPs remains at 14,533 metric tonnes, consistent with 2024 levels.^[45]^[46]^[47]^[48] The current's cold water masses also facilitate the southward extension of Arctic species, such as polar cod (Boreogadus saida), which preferentially inhabit sub-zero temperatures and low-salinity Arctic inflows along the Labrador shelf. Polar cod, often comprising a dominant portion of fish biomass in these frigid zones, feeds primarily on copepods and amphipods, linking ice-associated and pelagic food webs. This results in a pronounced biodiversity gradient: sub-Arctic communities near the current's core feature high abundances of cold-adapted species like polar cod, transitioning southward to more diverse temperate assemblages influenced by mixing with warmer Gulf Stream waters.^[49]^[50] Climate-driven alterations to the Labrador Current, including potential weakening or eastward shifts due to stronger winds, pose significant risks to these marine communities by promoting deoxygenation and warming, which could displace cold-water species like polar cod and cod toward the north. Such distributional shifts may disrupt food webs, reduce habitat suitability for Arctic biota, and exacerbate declines in commercial stocks, threatening fisheries yields in Newfoundland and Labrador that historically exceeded 1 million tonnes annually across groundfish and forage species prior to the 1990s collapses. Ongoing warming is already linked to smaller body sizes in affected species like cod due to hypoxic stress, further impacting fishery productivity and economic viability. However, as of 2025, Northern cod stocks show signs of recovery, with the TAC increased to 18,000 tonnes for the 2025-26 season, reflecting a biomass estimate rise of approximately 100,000 metric tons from 2024.^[36]^[51]^[52]^[53]

History and Research

Early Discovery

The Labrador Current was first noted during 19th-century whaling voyages in the Arctic, where explorers encountered persistent cold waters flowing southward along the eastern coast of North America. These observations described cold coastal waters influenced by Arctic inflows, carrying icebergs southward and creating hazardous navigation conditions due to abrupt temperature contrasts with warmer Atlantic waters. Formal recognition of the Labrador Current as a distinct oceanic feature came in the mid-19th century through systematic hydrographic surveys along the North American coast. These efforts integrated ship-based observations, highlighting temperature gradients and salinity differences, and established the current's path from Arctic sources through Hudson Strait, as well as its influence on regional climate and maritime safety. By the 1870s, early nautical charts began to delineate the Labrador Current's trajectory with greater precision, relying on aggregated data from ship drifts and temperature measurements. Matthew Fontaine Maury, superintendent of the U.S. Naval Observatory's Depot of Charts and Instruments, incorporated such observations into his influential wind and current charts of the North Atlantic, portraying the current as a southward-flowing stream of icy water hugging the Labrador coast before veering offshore near the Grand Banks. Maury's mappings, derived from thousands of logbooks submitted by mariners, underscored the current's velocity—typically 0.5 to 1 knot—and its basis in empirical drift patterns, providing navigators with essential guidance while advancing scientific understanding of subpolar circulation.

Modern Monitoring and Studies

The International Ice Patrol (IIP) was established in 1914 in response to the sinking of the RMS Titanic, with the mandate to monitor iceberg threats in the North Atlantic shipping lanes, including those transported southward by the Labrador Current.^[54] Operating under the U.S. Coast Guard, the IIP employs a combination of ship-based observations from Coast Guard cutters and aerial reconnaissance using HC-130J aircraft equipped with radar and visual detection systems to track iceberg positions and drift patterns along the Labrador coast and Grand Banks.^[54] These methods provide real-time warnings to mariners, with annual reports documenting thousands of icebergs detected, primarily originating from Greenland calving and carried by the current's flow.^[54] Advancements in satellite technology have enhanced monitoring of the Labrador Current's dynamics since the 1990s. The TOPEX/Poseidon mission, launched in 1992, utilized radar altimetry to measure sea surface height anomalies, enabling estimates of geostrophic currents and volume transport variations in the Labrador Sea, such as a decline of approximately 6.3 Sv in the 1990s followed by a partial rebound of 3.2 Sv in the early 2000s.^[55] Complementing this, the Argo float array, deployed globally since 2000, provides autonomous, real-time profiles of temperature, salinity, and velocity in the upper 2000 m of the ocean, including the Labrador region, where floats drifting at parking depths of around 1000 m reveal seasonal overturning patterns and water mass transformations driven by the current.^[56] The Overturning in the Subpolar North Atlantic Program (OSNAP), initiated in the 2010s, has advanced understanding of the Labrador Current's role in Atlantic Meridional Overturning Circulation (AMOC) variability through moored arrays and repeat hydrographic sections across the subpolar gyre.^[57] Key findings indicate that anomalous dense Labrador Sea Water production drives multidecadal AMOC fluctuations, with the current projected to export increased freshwater southward at rates of approximately 0.014 Sv per decade for the Davis Strait component under greenhouse warming scenarios through 2100, contributing to broader ocean circulation changes.^[6] These observations underscore the current's influence on regional climatic patterns, such as altered heat transport.^[57] Recent OSNAP studies (2020–2025) have further refined transport estimates across the subpolar North Atlantic, showing simulated and observed overturning transports consistent with ongoing monitoring.^[58] Additional research highlights the Labrador Current's role in restricting Arctic freshwater spread, limiting impacts on open-ocean convection and AMOC, alongside evidence of AMOC weakening coupled with strengthened deep convection in the Labrador Sea due to freshening.^[6]^[59] As of 2025, surface drifter data (1990–2023) reveal detailed pathways of Baffin Bay and Hudson Bay waters on the Labrador Shelf.^[21]

References

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Aug 8, 2010 · In this paper, we synthesize satellite altimetry sea surface height observations with CTD data to calculate the total geostrophic current and to ...Missing: gravimetric, | Show results with:gravimetric,
[15]
Origin and Composition of Seasonal Labrador Sea Freshwater
The depth of winter convection in the central Labrador Sea is strongly influenced by the prevailing stratification in late summer.
[16]
Volume and freshwater transports through the Canadian Arctic ...
Nov 2, 2011 · [1] Baffin Bay connects the Arctic Ocean and the Labrador Sea. It receives Polar water through the Canadian Arctic Archipelago and by the ...1. Introduction · 2. A Baroclinic Approach · 4. A Barotropic Correction
[17]
Seasonal Cycle of the Coastal West Greenland Current System ...
May 6, 2021 · The shelf based West Greenland Current System carries both Arctic Water and Greenland meltwater around Cape Farewell, the southern tip of Greenland.
[18]
Annual Velocity Variations in the Labrador Current
The surface layer of salinities lower than 33.0 and temperatures warmer than -1.5°C are typical of midsummer conditions. In the surface layer over the shelf ( ...
[19]
The outflow from Hudson Strait and its contribution to the Labrador ...
The Hudson Strait outflow accounts for approximately 15% of the volume and 50% of the fresh water transports of the Labrador Current.
[20]
Circulation of Baffin Bay and Hudson Bay waters on the Labrador ...
Jan 28, 2025 · Our results suggest that if an increasing amount of freshwater reaches the Labrador shelf, it would not directly affect the Labrador Sea ...
[21]
Recent increases in Arctic freshwater flux affects Labrador Sea ...
Jan 22, 2016 · ... Cape Farewell; melt water from southwestern Greenland joins the West Greenland Current, similarly merging with the Irminger Current (Fig. 1) ...<|separator|>
[22]
Freshwater export from the Labrador Current to the North Atlantic ...
Recent studies indicate that as much as 90% of the total volume and freshwater transport that arrives on the Labrador Shelf in the shelfbreak current is lost ...
[23]
[PDF] North Atlantic Ocean surface currents
Large average currents are found near its northern flank southeast of Flemish Cap. ... traced westward to the Labrador Current, and near the tail of the bank near ...
[24]
Labrador Sea Boundary Currents and the Fate of the Irminger Sea ...
Above the northern slope of the basin, the surface drifters have two preferential paths: one between the 1000-m and 2000-m isobaths and the other close to the ...Missing: route | Show results with:route
[25]
[PDF] Temporal Variability of the Labrador Current Pathways Around the ...
Feb 18, 2023 · We found that the Labrador Current can be completely blocked by Gulf Stream eddies and meanders that impinge on the shelf break along the Grand ...Missing: description | Show results with:description
[26]
Interannual to decadal variability of outflow from the Labrador Sea
Dec 31, 2010 · ... Labrador Current (LC) with its strong baroclinic structure and ... Four depth levels have been selected: Upper Layer (200 m), Labrador ...
[27]
Boundary Circulation at the Exit of the Labrador Sea in - AMS Journals
Maximum flow in the LSW layer is located at 2500-m water depth, seaward of the traditional Labrador Current and with weak vertical shear. The record from ...
[28]
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010GL045321
[29]
Large-scale control of the retroflection of the Labrador Current - Nature
May 6, 2023 · We examine the retroflection of the Labrador Current from Lagrangian tracking experiments where virtual particles are tracked using velocity ...<|control11|><|separator|>
[30]
Iceberg migration - Canada.ca
Sep 10, 2017 · Icebergs travel in the Baffin Island Current and then the Labrador Current south of Hudson Bay. Finally, they reach the Grand Banks of Newfoundland.<|control11|><|separator|>
[31]
A Greenland glacier is growing. That doesn't mean melting is over.
Mar 25, 2019 · Twenty billion tons of ice dump into the sea from Jakobshavn annually, more than anywhere besides Antarctica, with bergs scooped by the Labrador ...
[32]
Newfoundland and Labrador Iceberg Facts
90% of icebergs seen off Newfoundland and Labrador come from the glaciers of western Greenland. ... Labrador Current which carries them south into Iceberg Alley.Missing: transport | Show results with:transport
[33]
The North Atlantic Ice Menace and the Work of Protection ...
There are records of phenomenally far southern drifts in which Arctic ice has been sighted near the Azores and Bermuda, but such cases are exceedingly rare. The ...Missing: transports | Show results with:transports<|separator|>
[34]
What controls the pathways of the Labrador Current?
Jun 28, 2023 · According to the researchers, winds over the Labrador coast appear to play a role, with stronger winds veering the Labrador Current eastward.Missing: joins gyre
[35]
Cold Ocean: Newfoundland and Labrador Heritage Web
Over the Grand Bank it turns southwest and a branch current flows westward along the south coast of the island and into the Gulf of St. Lawrence through the ...
[36]
https://www.mcgill.ca/newsroom/channels/news/what-controls-pathways-labrador-current-348902
[37]
[PDF] The Labrador Sea Deep Convection Experiment - Oceans at MIT
dimension 500 km × 700 km × 2 km deep has devel- oped in response to this ... southwestward flowing Labrador Current that even- tually makes its way ...
[38]
Atmospheric forcing during active convection in the Labrador Sea ...
Sep 1, 2016 · Well-defined storm tracks toward Greenland result in the largest heat fluxes in the Labrador Sea; The canonical low-pressure system that drives ...
[39]
Seasonality of the inshore Labrador current over the Newfoundland ...
Aug 8, 2025 · In terms of nutrients, the LC transports Arctic water particularly rich in nitrate, phosphate, and especially silicate to subarctic regions ...
[40]
Persistent Phytoplankton - NASA Earth Observatory
Sep 21, 2020 · The recent blooms have occurred near the edge of the Grand Banks and ... Those abundant nutrients can enhance the productivity of phytoplankton.Missing: flux 100-200 gC/ m²/<|control11|><|separator|>
[41]
Timing and magnitude of spring bloom and effects of physical ...
Aug 2, 2013 · In this study, we investigate temporal and spatial variations of spring-bloom timing and intensity over the Grand Banks of Newfoundland
[42]
Satellite-derived primary production estimates from the Grand Banks
For the entire Banks, production is estimated to be 193 g C m−2 y−1, which compares well with measured values of annual primary production on the Grand Banks ( ...Missing: gC | Show results with:gC
[43]
[PDF] A Multispecies Size-Spectrum Model of the Grand Banks - EcoEvoRxiv
The Grand Banks is a dynamic system,. 52 shaped by the nutrient-rich Labrador Current and the warmer North Atlantic Current,. 53 supports distinct seasonal ...<|separator|>
[44]
Decadal changes in biomass and distribution of key fisheries ...
Apr 1, 2024 · The Grand Banks is a highly productive region where two distinct water masses, the Labrador Current and the Gulf Stream, converge. The ...
[45]
Comparative Modeling of Cod-Capelin Dynamics in the ... - Frontiers
Mar 8, 2021 · Capelin availability and fishing are common and important drivers of cod dynamics in NL and BS (e.g., Rose and O'Driscoll, 2002; Lilly et al., ...
[46]
Polar cod (Boreogadus saida) and capelin (Mallotus villosus) as key ...
Both polar cod and capelin are key species in the Arctic marine food web, although the polar cod is more important in the high-Arctic systems and capelin ...
[47]
[PDF] Stateof the Arctic Marine Biodiversity
2011): polar cod, Greenland halibut and the capelin complex. Polar cod is an Arctic species with a circumpolar distribution whereas capelin and Greenland.
[48]
Environmental control on the productivity of a heavily fished ecosystem
Jun 6, 2025 · We show that cyclical changes in the Newfoundland and Labrador (NL) ecosystems productivity, from primary producers to piscivorous fish, coincide with changes ...
[49]
The northern cod crisis (BP-313E) - à www.publications.gc.ca
(15) It is noteworthy that the TAC of 235,000 tonnes for 1989 was exceeded because of foreign fishing on the Nose of the Grand Bank (NAFO area 3L) despite a ...
[50]
The Gulf Stream and Its Problems - jstor
the Coast Survey under the superintendency of Alexander Dallas. Bache, a ... of the Labrador Current across the Great Bank, but that it "turns sharply ...
[51]
[PDF] Report of the International Ice Patrol in the North Atlantic - navcen
Similar to 2020, which saw 169 icebergs entering the shipping lanes, slow formation of sea ice and warm temperatures at the end of 2020 created environmental ...
[52]
Decline and partial rebound of the Labrador Current 1993–2004 ...
Dec 4, 2010 · Using the TOPEX/Poseidon (T/P) and Geosat altimeter data, Han and Ikeda [1996] found the predominance of the steric height effect over the wind- ...
[53]
Seasonal Overturning of the Labrador Sea as Observed by Argo ...
Argo floats are used to investigate Labrador Sea overturning and its variability on seasonal time scales. This is the first application of Argo floats to ...
[54]
An outsized role for the Labrador Sea in the multidecadal variability ...
Oct 6, 2021 · Multidecadal AMOC variability can be traced to anomalous production of dense Labrador Sea Water with buoyancy forcing in the western subpolar gyre playing a ...