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The North-Atlantic Current and Mid-Atlantic Sub-Polar Frontal System

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The North-Atlantic Current and Mid-Atlantic Sub-Polar Frontal System 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
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