| 英文摘要: | The emergence of new Arctic trade routes will probably change the global dynamics of invasive species, potentially affecting marine habitats and ecosystem functions, especially in coastal regions. With striking reductions in Arctic sea-ice coverage in recent years1, 2, a long-anticipated opportunity for modern interocean shortcuts is being realized. The first commercial bulk carrier loaded with British Columbian coal successfully transited the Northwest Passage in September 20133. Perhaps more importantly, ships in larger numbers are already navigating the icy waters of Norway and Russia through the Northeastern Passage, also known as the northern sea route (NSR) — a 3,000 mile passage along Russia's northern coast that connects the Barents and Bering seas. The Russian Federation's Northern Sea Route Administration, which issues permits, provides icebreaker escort and regulates commercial ships traversing the NSR, is now open for business4, 5. Among many potential environmental effects, the continued expansion of Arctic shipping will alter the risk of biological invasions in coastal ecosystems on both regional and global scales. Commercial ships are a dominant mechanism for the introduction of non-native marine species6, 7. A diverse range of organisms is unintentionally transferred in ballast tanks and on the hulls of ships8, 9, 10. A major shift in trade-routes will alter the current landscape of marine invasion dynamics, affecting the transfer, establishment and potential consequences of invasions. There are two categories of commercial Arctic shipping: (1) trans-Arctic voyages, whereby ships use the Arctic as a thoroughfare for interocean passage; (2) destination shipping that moves goods to and from the Arctic (for example, import of oil extraction equipment and export of liquefied natural gas; LNG). Increased opportunity for invasions of the Arctic are an important concern, but trans-Arctic shipping will also change global commerce patterns significantly, connecting world ports and their biota in unprecedented ways. The melting of Arctic sea ice is connecting the North Pacific and North Atlantic oceans for the first time in several million years11. Although an ice-free Arctic provides a new interocean corridor for natural dispersal of marine biota across the region, it also represents a new route for long-distance transport of organisms by ships. Ratification of the maritime delimitation and cooperation in the Barents Sea and the Arctic Ocean treaty, between Norway and Russia in 2011, has settled a decades-long dispute over territorial waters and opened a 175,000 km2 region of the Barents Sea and Arctic Ocean to oil and gas exploration12. This pivotal international agreement paves the way for less politically and legally complicated NSR passage while increasing the opportunity for shipping-related activities in petroleum-rich Arctic waters. The volume of trans-Arctic shipping traffic is increasing rapidly. Using NSR shipping statistics5, we plotted annual transits for the 2009–2013 shipping seasons and fitted a growth curve (Fig. 1). In 2013, 71 vessels were reported to have made transit through the NSR, and at least 481 were issued permits to operate inside the NSR5. Although the current volume of NSR traffic is still meagre compared with other major shipping routes, it is expanding as quickly, with a projected average annual increase of 20% per year over the next 25 years. At this rate, an estimated 5,600 trans-Arctic transits per year could occur by the year 2040 through the NSR alone. Although this projection provides an initial base function, it will no doubt be strongly affected by three important economic factors: (1) the substantially shorter route between Asia and Europe than afforded by either the Suez or Panama canals; (2) increasing predictability, duration and safety of ice-free conditions; (3) the opportunity for exploration, extraction and exportation of the Arctic's natural resource reserves.
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