scholarly journals Regional and temporal variation of Oithona spp. biomass, stage structure and productivity in the Irminger Sea, North Atlantic

2007 ◽  
Vol 29 (12) ◽  
pp. 1051-1070 ◽  
Author(s):  
C. Castellani ◽  
X. Irigoien ◽  
R. P. Harris ◽  
N. P. Holliday
Keyword(s):  
Temporal Variation ◽  
North Atlantic ◽  
Stage Structure ◽  
Irminger Sea

scholarly journals Dissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)

2018 ◽  
Author(s):  
Manon Tonnard ◽  
Hélène Planquette ◽  
Andrew R. Bowie ◽  
Pier van der Merwe ◽  
Morgane Gallinari ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
Sea Water ◽  
North Atlantic Ocean ◽  
Deep Convection ◽  
Labrador Sea ◽  
Intermediate Water ◽  
The North ◽  
Irminger Sea ◽  
The North Atlantic

Abstract. Dissolved Fe (DFe) samples from the GEOVIDE voyage (GEOTRACES GA01, May–June 2014) in the North Atlantic Ocean were analysed using a SeaFAST-picoTM coupled to an Element XR HR-ICP-MS and provided interesting insights on the Fe sources in this area. Overall, DFe concentrations ranged from 0.09 ± 0.01 nmol L−1 to 7.8 ± 0.5 nmol L−1. Elevated DFe concentrations were observed above the Iberian, Greenland and Newfoundland Margins likely due to riverine inputs from the Tagus River, meteoric water inputs and sedimentary inputs. Air-sea interactions were suspected to be responsible for the increase in DFe concentrations within subsurface waters of the Irminger Sea due to deep convection occurring the previous winter, that provided iron-to-nitrate ratios sufficient to sustain phytoplankton growth. Increasing DFe concentrations along the flow path of the Labrador Sea Water were attributed to sedimentary inputs from the Newfoundland Margin. Bottom waters from the Irminger Sea displayed high DFe concentrations likely due to the dissolution of Fe-rich particles from the Denmark Strait Overflow Water and the Polar Intermediate Water. Finally, the nepheloid layers were found to act as either a source or a sink of DFe depending on the nature of particles.

scholarly journals Mean circulation and EKE distribution in the Labrador Sea Water level of the subpolar North Atlantic

2018 ◽  
Author(s):  
Jürgen Fischer ◽  
Johannes Karstensen ◽  
Marilena Oltmanns ◽  
Sunke Schmidtko
Keyword(s):  
Flow Field ◽  
North Atlantic ◽  
Sea Water ◽  
Labrador Sea ◽  
Mean Flow ◽  
Southern Boundary ◽  
Mapping Algorithms ◽  
Iceland Basin ◽  
Irminger Sea ◽  
Labrador Sea Water

Abstract. A long term mean flow field for the subpolar North Atlantic region with a horizontal resolution of approximately 25 km is created by gridding Argo-derived velocity vectors using two different topography following interpolation schemes. The 10-d float displacements in the typical drift depths of 1000 m to 1500 m represent the flow in the Labrador Sea Water density range. Both mapping algorithms separate the flow field into potential vorticity (PV) conserving, i.e. topography following contribution and a deviating part, which we define as the eddy contribution. To verify the significance of the separation, we compare the mean flow and the eddy kinetic energy (EKE), derived from both mapping algorithms, with those obtained from multiyear mooring observations. The PV-conserving mean flow is characterized by stable boundary currents along all major topographic features including shelf breaks and basin-interior topographic ridges such as the Reykjanes Ridge or the Rockall Plateau. Mid-basin northward advection pathways from the northeastern Labrador Sea into the Irminger Sea and from the Mid Atlantic Ridge region into the Iceland basin are well-resolved. An eastward flow is present across the southern boundary of the subpolar gyre near 52° N, the latitude of the Charlie Gibbs Fracture Zone. The mid-depth EKE field resembles most of the satellite-derived surface EKE field. However, noticeable differences exist along the northward advection pathways in the Irminger Sea and the Iceland basin, where the deep EKE exceeds the surface EKE field. Further, the ratio between mean flow and the square root of the EKE, the Peclet Number, reveals distinct advection-dominated regions as well as basin interior regimes in which mixing is prevailing.

scholarly journals Feeding of Calanus finmarchicus and Oithona similis on the microplankton assemblage in the Irminger Sea, North Atlantic

2008 ◽  
Vol 30 (10) ◽  
pp. 1095-1116 ◽  
Author(s):  
C. Castellani ◽  
X. Irigoien ◽  
D. J. Mayor ◽  
R. P. Harris ◽  
D. Wilson
Keyword(s):  
North Atlantic ◽  
Calanus Finmarchicus ◽  
Oithona Similis ◽  
Irminger Sea

scholarly journals Mean circulation and EKE distribution in the Labrador Sea Water level of the subpolar North Atlantic

Ocean Science ◽  
2018 ◽  
Vol 14 (5) ◽  
pp. 1167-1183 ◽  
Author(s):  
Jürgen Fischer ◽  
Johannes Karstensen ◽  
Marilena Oltmanns ◽  
Sunke Schmidtko
Keyword(s):  
Flow Field ◽  
North Atlantic ◽  
Sea Water ◽  
Labrador Sea ◽  
Mean Flow ◽  
Southern Boundary ◽  
Mapping Algorithms ◽  
Iceland Basin ◽  
Irminger Sea ◽  
Labrador Sea Water

Abstract. A long-term mean flow field for the subpolar North Atlantic region with a horizontal resolution of approximately 25 km is created by gridding Argo-derived velocity vectors using two different topography-following interpolation schemes. The 10-day float displacements in the typical drift depths of 1000 to 1500 m represent the flow in the Labrador Sea Water density range. Both mapping algorithms separate the flow field into potential vorticity (PV) conserving, i.e., topography-following contribution and a deviating part, which we define as the eddy contribution. To verify the significance of the separation, we compare the mean flow and the eddy kinetic energy (EKE), derived from both mapping algorithms, with those obtained from multiyear mooring observations. The PV-conserving mean flow is characterized by stable boundary currents along all major topographic features including shelf breaks and basin-interior topographic ridges such as the Reykjanes Ridge or the Rockall Plateau. Mid-basin northward advection pathways from the northeastern Labrador Sea into the Irminger Sea and from the Mid-Atlantic Ridge region into the Iceland Basin are well-resolved. An eastward flow is present across the southern boundary of the subpolar gyre near 52∘ N, the latitude of the Charlie Gibbs Fracture Zone (CGFZ). The mid-depth EKE field resembles most of the satellite-derived surface EKE field. However, noticeable differences exist along the northward advection pathways in the Irminger Sea and the Iceland Basin, where the deep EKE exceeds the surface EKE field. Further, the ratio between mean flow and the square root of the EKE, the Peclet number, reveals distinct advection-dominated regions as well as basin-interior regimes in which mixing is prevailing.

scholarly journals Observations of Irminger Sea Anticyclonic Eddies

2013 ◽  
Vol 43 (4) ◽  
pp. 805-823 ◽  
Author(s):  
Xue Fan ◽  
Uwe Send ◽  
Pierre Testor ◽  
Johannes Karstensen ◽  
Pascale Lherminier
Keyword(s):  
North Atlantic ◽  
Velocity Structure ◽  
Kinematic Model ◽  
Labrador Sea ◽  
Core Diameter ◽  
Norwegian Sea ◽  
Irminger Sea ◽  
Salinity Anomaly ◽  
Anticyclonic Eddies ◽  
Clear Increase

Abstract Mesoscale anticyclonic eddies in the Irminger Sea are observed using a mooring and a glider. Between 2002 and 2009, the mooring observed 53 anticyclones. Using a kinematic model, objective estimates of eddy length scales and velocity structure are made for 16 eddies. Anticyclones had a mean core diameter of 12 km, and their mean peak observed azimuthal speed was 0.1 m s−1. They had core salinities and potential temperatures of 34.91–34.98 and 4.48°–5.34°C, respectively, making them warm and salty features. These properties represent a typical salinity anomaly of 0.03 and a temperature anomaly of 0.28°C from noneddy values. All eddies had small (≪1) Rossby numbers. In 2006, the glider observed two anticyclones having diameters of about 20 km and peak azimuthal speeds of about 0.3 m s−1. Similar salinity anomalies were detected throughout the Irminger Sea by floats profiling in anticyclones. Two formation regions for the eddies are identified: one to the west of the Reykjanes Ridge and the other off the East Greenland Irminger Current near Cape Farewell close to the mooring. Observations indicate that eddies formed in the former region are larger than eddies observed at the mooring. A clear increase in eddy salinity is observed between 2002 and 2009. The observed breakup of these eddies in winter implies that they are a source of salt for the central gyre. The anticyclones are similar to those found in both the Labrador Sea and Norwegian Sea, making them a ubiquitous feature of the subpolar North Atlantic basins.

Deep-water life cycle of Anisakis paggiae (Nematoda: Anisakidae) in the Irminger Sea indicates kogiid whale distribution in north Atlantic waters

Polar Biology ◽  
2011 ◽  
Vol 34 (6) ◽  
pp. 899-906 ◽  
Author(s):  
Sven Klimpel ◽  
Thomas Kuhn ◽  
Markus W. Busch ◽  
Horst Karl ◽  
Harry W. Palm
Keyword(s):  
Life Cycle ◽  
North Atlantic ◽  
Deep Water ◽  
Irminger Sea

scholarly journals Variability in North Atlantic marine radiocarbon reservoir effects at c. AD 1000

The Holocene ◽  
2006 ◽  
Vol 16 (1) ◽  
pp. 131-136 ◽  
Author(s):  
P. L. Ascough ◽  
G. T. Cook ◽  
M. J. Church ◽  
A. J. Dugmore ◽  
S. V. Arge ◽  
...  
Keyword(s):  
Temporal Variation ◽  
North Atlantic ◽  
Climatic Conditions ◽  
Spatial And Temporal Variation ◽  
Archaeological Sites ◽  
Driving Mechanism ◽  
Reservoir Effect ◽  
The North ◽  
The North Atlantic ◽  
Precision And Accuracy

14C age measurements made on samples from three archaeological sites located on North Atlantic coasts were used to investigate the marine reservoir effect (MRE) at c.AD 1000. This is an important period within human cultural and palaeoenvironmental research as it is a time when Norse expansion to the North Atlantic islands occurred, during what appears to be a period of ameliorating climatic conditions. This makes improved chronological precision and accuracy at this time highly desirable. The data indicate a potential latitudinal variation in MRE at c. AD 1000 from a ΔR of-142±16 14C yr at Omey Island (53° 32' N) to 64±13 14C yr at Undir Junkarinsfløtti (61° 51' N). The results are compared with modern assessments of MRE values within the context of oceanographic and climatic regimes that provide a possible driving mechanism for spatial and temporal variation in MRE.

Sign in / Sign up

Export Citation Format

Share Document