Template for Submission of Scientific Information to Describe Areas Meeting Scientific Criteria for Ecologically or Biologically Significant Marine Areas
The North-Atlantic Current and mid-Atlantic sub-polar frontal system
Abstract (in less than 150 words) The North-Atlantic Current (NAC) dominates the ocean circulation of the North Atlantic (Miller et al. 2013). This is an area of intense mesoscale activity with near stationary eddies and numerous thermal fronts aligned in zonal bands (Read et al. 2010). These fronts and eddies enhance primary production, and retain and concentrate secondary productivity both vertically and horizontally, and the combination of localised high intensity mixing in the eddies results in patchy but high surface productivity at fine scales (Vecchione et al. 2015). Seabird tracking data confirms this is an area of high productivity, with a high intensity of foraging activity in the area, suggesting that productivity cascades to higher trophic levels.
Introduction (To include: feature type(s) presented, geographic description, depth range, oceanography, general information data reported, availability of models) The North-Atlantic Current (NAC) is the main northward branch of the Gulf Stream (Krauss 1986) Rossby 1996), transporting warm water towards higher latitudes. After splitting from the Gulf Stream near the Tail of the Grand Banks of Newfoundland and extending north into the Labrador Sea, the NAC turns east at the so-called Northwest Corner and flows eastward. The front associated with the NAC is called the Subpolar (or Subarctic) Front (Belkin & Levitus 1996). The Subpolar Front is a relatively wide region that separates the subtropical gyre from the subpolar gyre and where the main thermocline shoals to the surface (Rossby 1996). The NAC is different from surrounding areas and can be visualised through satellite altimetry and NEMO (Nucleus for European Modelling of the Ocean) ocean models (e.g., Miller et al. 2013; Marzocchi et al. 2015) and oceanographic sections (Belkin & Levitus 1996) (Figure 1). The NAC pathways are not randomly located but remain between a number of preferred latitudes, with surface thermal fronts appearing in a banded structure, aligned west to east in the area south of the Charlie-Gibbs Fracture Zone (CGFZ), and aligned roughly SW to NE in the north. This alignment follows the direction of the NAC (Miller et al. 2013). The NAC is a transition zone and has a wide banded structure with distinct water types that get progressively cooler and fresher from south to north separated by the three branches and their density fronts. The fronts are associated with vigorous vertical velocities (bringing nutrients to the surface) and some horizontal exchange, especially southward from the subpolar region (Dutkiewicz et al. 2001). Density contrasts across the fronts lead to instability and the development of eddies (Volkov 2005). These eddies enhance and concentrate primary production and represent an important habitat for oceanic higher predators, including seabirds. The importance of this area for oceanic higher predators is evident from tracking data of seabirds, turtles, whales, sharks and tunas, which frequently target areas of higher prey availability. A large quantity of seabird tracking data confirms this is an area of high productivity, with a high intensity of foraging activity in the area (Figure 2). Seabird tracking data shows 21 species of seabird foraging in the area including Endangered Zino's Petrel Pterodroma madeira, Endangered Bermuda Petrel Pterodroma cahow, Vulnerable Atlantic Puffin Fratercula arctica, and Vulnerable Black-legged Kittiwake Rissa tridactyla. This site is identified from in situ and remote sensing (or satellite) data, and validated with biological data (seabird tracking data).
Location (Indicate the geographic location of the area/feature. This should include a location map.) The NAC has a well-defined western boundary (front) defined by the continental shelf slope. It extends north along the east flank of the Grand Banks where it forms a loop called the Northwest Corner and continues to the east. The northern boundary is defined by the northern extent of the Subpolar Front at 54°N. The North Subarctic Front is topographically fixed at CGFZ (Belkin & Levitus 1996), and could
The North-Atlantic Current and mid-Atlantic sub-polar frontal system 1 be set at 30°W. It is known that the NAC and frontal branches vary strongly, with latitudinal shifts up to 250-300km (Belkin & Levitus 1996), thus maps of annual means have been used to ensure the full temporal variability has been captured (Marzocchi et al. 2015). Figure 1.
Feature description of the proposed area (This should include information about the characteristics of the feature to be proposed, e.g. in terms of physical description (water column feature, benthic feature, or both), biological communities, role in ecosystem function, and then refer to the data/information that is available to support the proposal and whether models are available in the absence of data. This needs to be supported where possible with maps, models, reference to analysis, or the level of research in the area)
Feature condition and future outlook of the proposed area (Description of the current condition of the area – is this static, declining, improving, what are the particular vulnerabilities? Any planned research/programmes/investigations?)
Assessment of the area against CBD EBSA Criteria (Discuss the area in relation to each of the CBD criteria and relate the best available science. Note that a proposed area for EBSA description may qualify on the basis of one or more of the criteria, and that the polygons of the EBSA need not be defined with exact precision. And modeling may be used to estimate the presence of EBSA attributes. Please note where there are significant information gaps)
CBD EBSA Description Ranking of criterion relevance Criteria (Annex I to decision IX/20) (please mark one column with an X) (Annex I to No Low Medi High decision informat um IX/20) ion Uniqueness Area contains either (i) unique (“the only one of or rarity its kind”), rare (occurs only in few locations) or endemic species, populations or communities, and/or (ii) unique, rare or distinct, habitats or ecosystems; and/or (iii) unique or unusual geomorphological or oceanographic features. Explanation for ranking (must be accompanied by relevant sources of scientific articles, reports or documents) This area features numerous fronts that form an extremely rich frontal pattern (Belkin and Levitus 1986; Read et al. 2010; Miller et al. 2013). In terms of richness, this frontal pattern rivals the multi- frontal pattern of the Antarctic Circumpolar Current and Kuroshio-Oyashio region in the Northwest Pacific.
Special Areas that are required for a population to X importance survive and thrive. for life- history stages of species Explanation for ranking (must be accompanied by relevant sources of scientific articles, reports or documents) The area is a globally important migratory seabird foraging area, primarily used during the non- breeding or winter season. Tracking shows 21 species foraging in the area (Figure 2). Birds travel to the area from colonies in both the North and South Atlantic. Important site for seabirds including Black-legged Kittiwake Rissa tridactyla, Thick-billed Murre Uria lomvia, Audubon’s Shearwater Puffinus lherminieri (OSPAR listed threatened and/or declining species) (OSPAR 2009a-c).
Importance Area containing habitat for the survival and X for recovery of endangered, threatened, declining threatened, species or area with significant assemblages of endangered such species. or declining
The North-Atlantic Current and mid-Atlantic sub-polar frontal system 2 species and/or habitats Explanation for ranking (must be accompanied by relevant sources of scientific articles, reports or documents) Seabird tracking data shows 21 species of seabird foraging in the area including Endangered Zino's Petrel Pterodroma madeira, Endangered Bermuda Petrel Pterodroma cahow, Vulnerable Atlantic Puffin Fratercula arctica, and Vulnerable Black-legged Kittiwake Rissa tridactyla. In addition to Thick-billed Murre Uria lomvia and Audubon’s Shearwater Puffinus lherminieri listed by OSPAR as threatened and/or declining species.
Vulnerability, Areas that contain a relatively high proportion X fragility, of sensitive habitats, biotopes or species that are sensitivity, or functionally fragile (highly susceptible to slow recovery degradation or depletion by human activity or by natural events) or with slow recovery. Explanation for ranking (must be accompanied by relevant sources of scientific articles, reports or documents) The area is of high importance to numerous Globally Threatened Species that have suffered significant population declines – including Endangered Zino's Petrel Pterodroma madeira, Endangered Bermuda Petrel Pterodroma cahow, Vulnerable Atlantic Puffin Fratercula arctica, and Vulnerable Black-legged Kittiwake Rissa tridactyla. In addition, the area is used by Thick-billed Murre Uria lomvia and Audubon’s Shearwater Puffinus lherminieri, which are listed by OSPAR as threatened and/or declining species. Black-legged Kittiwake Rissa tridactyla (BirdLife International 2019) is listed as Vulnerable because of declines due to the depletion of food resources (e.g. through over-fishing) (Frederiksen et al. 2004, Nikolaeva et al. 2006), marine oil spills (Nikolaeva et al. 2006) and chronic oil pollution (Nikolaeva et al. 2006).
Biological Area containing species, populations or X productivity communities with comparatively higher natural biological productivity. Explanation for ranking (must be accompanied by relevant sources of scientific articles, reports or documents) Both satellite altimetry and numerous thermal fronts show this is an area of high mesoscale activity with near stationary eddies and thermal fronts aligned in zonal bands (Read et al. 2010). The fronts retain and concentrate productivity both vertically and horizontally, and the combination of localised high intensity mixing in the eddies results in patchy but high surface productivity at fine scales (Vecchione et al. 2015). Seabird tracking data confirms this is an area of high productivity, with a high intensity of foraging activity in the area (BirdLife International, in prep).
Biological Area contains comparatively higher diversity of X diversity ecosystems, habitats, communities, or species, or has higher genetic diversity. Explanation for ranking (must be accompanied by relevant sources of scientific articles, reports or documents) This area comprises a transition from the subtropical ocean to the subpolar (subarctic) ocean. As such, this area features several well-defined water masses separated by well-defined fronts. Each water mass contains a distinct ecosystem, while fronts act as ecotones, ensuring the high diversity of ecosystems and habitats in this area (Read et al. 2010; Miller et al. 2013). Analyses of tracking data from over 2,000 individual seabirds indicate that the area is intensively used by 21 species (BirdLife International, in prep): - Arctic Tern Sterna paradisaea (LC) - Atlantic Puffin Fratercula arctica (VU) - Audubon’s Shearwater Puffinus lherminieri (LC) - Bermuda Petrel Pterodroma cahow (EN) - Black-legged Kittiwake Rissa tridactyla (VU) - Bulwer’s Petrel Bulweria bulwerii (LC)
The North-Atlantic Current and mid-Atlantic sub-polar frontal system 3 - Common Murre Uria aalge (LC) - Cory’s Shearwater Calonectris borealis (LC) - Desertas Petrel Pterodroma deserta (VU) - Great Shearwater Ardenna gravis (LC) - Great Skua Catharacta skua (LC) - Little Auk Alle alle (LC) - Long-tailed Jaeger Stercorarius longicaudus (LC) - Manx Shearwater Puffinus puffinus (LC) - Northern Fulmar Fulmarus glacialis (LC) - Razorbill Alca torda (NT) - Sabine’s Gull Xema sabini (LC) - Sooty Shearwater Ardenna grisea (NT) - South Polar Skua Catharacta maccormicki (LC) - Thick-billed Murre Uria lomvia (LC) - Zino’s Petrel Pterodroma madeira (EN)
Naturalness Area with a comparatively higher degree of x naturalness as a result of the lack of or low level of human-induced disturbance or degradation. Explanation for ranking (must be accompanied by relevant sources of scientific articles, reports or documents)
Sharing experiences and information applying other criteria (Optional)
Other Description Ranking of criterion relevance Criteria (please mark one column with an X) Don’t Low Medium High Know Add relevant x criteria
Explanation for ranking (must be accompanied by relevant sources of scientific articles, reports or documents)
References (e.g. relevant documents and publications, including URL where available; relevant data sets, including where these are located; information pertaining to other relevant material, models, etc.) Belkin, I. M. & Levitus, S. (1996) Temporal variability of the subarctic front near the Charlie‐Gibbs fracture zone. Journal of Geophysical Research: Oceans 101(C12): 28317-28324. BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 30/08/2019. Dutkiewicz, S., Rothstein, L. & Rossby, T. (2001) Pathways of cross‐frontal exchange in the North Atlantic Current. Journal of Geophysical Research: Oceans 106(C11): 26917-26928. Frederiksen, M., Wanless, S., Harris, M. P., Rothery, P., Wilson, L. J. 2004. The role of industrial fisheries and oceanographic change in the decline of North Sea black-legged kittiwakes. Journal of Applied Ecology 41: 1129-1139. Krauss, W. (1986) The north Atlantic current. Journal of Geophysical Research: Oceans 91(C4): 5061-5074.
The North-Atlantic Current and mid-Atlantic sub-polar frontal system 4 Marzocchi, A., Hirschi, J. J. M., Holliday, N. P., Cunningham, S. A., Blaker, A. T. & Coward, A. C. (2015) The North Atlantic subpolar circulation in an eddy-resolving global ocean model. Journal of Marine Systems 142: 126-143. Miller, P. I., Read, J. F. & Dale, A. C. (2013) Thermal front variability along the North Atlantic Current observed using microwave and infrared satellite data. Deep Sea Research Part II: Topical Studies in Oceanography 98: 244-256. Nikolaeva, N.G.; Spiridonov, V.A.; Krasnov, Y.V. 2006. Existing and proposed marine protected areas and their relevance for seabird conservation: a case study in the Barents Sea region. In: G. Boere, C. Galbraith and D. Stroud (eds), Waterbirds around the world, pp. 743-749. The Stationery Office, Edinburgh, UK. OSPAR (2009a). Background document for Black-legged Kittiwake Rissa tridactyla. Biodiversity Series. OSPAR (2009b). Background document for Audubon’s Shearwater Puffinus lherminieri. Biodiversity Series. OSPAR (2009c). Background document for Thick-billed Murre Uria lomvia. Biodiversity Series Read, J., Pollard, R., Miller, P. & Dale, A. (2010) Circulation and variability of the North Atlantic Current in the vicinity of the Mid-Atlantic Ridge. Deep Sea Research Part I: Oceanographic Research Papers 57(3): 307-318. Rossby, T. (1996) The North Atlantic Current and surrounding waters: At the crossroads. Reviews of Geophysics 34(4): 463-481. Vecchione, M., Falkenhaug, T., Sutton, T., Cook, A., Gislason, A., Hansen, H. Ø., Heino, M., Miller, P. I., Piatkowski, U. & Porteiro, F. (2015) The effect of the North Atlantic Subpolar Front as a boundary in pelagic biogeography decreases with increasing depth and organism size. Progress in Oceanography 138: 105-115. Volkov, D. L. (2005) Interannual variability of the altimetry-derived eddy field and surface circulation in the extratropical North Atlantic Ocean in 1993–2001. Journal of Physical Oceanography 35(4): 405-426.
Maps and Figures
The North-Atlantic Current and mid-Atlantic sub-polar frontal system 5
Figure 1. Surface velocity in ORCA12 (5-day mean from the highest resolution model), considered the “best” representation of the NAC, showed with panel h for comparison with satellite altimetry. Adapted from Figure 8 F & H: Marzocchi, A., Hirschi, J. J. M., Holliday, N. P., Cunningham, S. A., Blaker, A. T. & Coward, A. C. (2015) The North Atlantic subpolar circulation in an eddy-resolving global ocean model. Journal of Marine Systems 142: 126-143 https://www.sciencedirect.com/science/article/pii/S0924796314002437
The North-Atlantic Current and mid-Atlantic sub-polar frontal system 6 Figure 2. Intensity of use by seabirds, identified by tracking data for 21 species (BirdLife International, in prep). The results are shown here are cropped to the OSPAR ABNJ area (Region V: wider Atlantic). This is the weighted average of the bird distribution during the stages associated with its respective year quarter, for all species and year quarters combined. (In order to facilitate the comparison of the relative importance of the areas, and only for mapping purposes, the average density index values were standardized to obtain values varying between 0 and 1, by dividing by the maximum value). The analysis was co
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The North-Atlantic Current and mid-Atlantic sub-polar frontal system 7