Oceanographic geographical features
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The MODIS marine chlorophyll a product provided, similar to SST, is a 4 km global monthly composite based on smaller resolution daily imagery compiled by NASA. The imagery is reliant on clear ocean (free of clouds and ice) so only months from March to October have been provided, as the chlorophyll levels in the Arctic diminish during the winter months, when sea ice is prevalent. The marine chlorophyll a is measured in mg/m3
We present the first digital seafloor geomorphic features map (GSFM) of the global ocean. The GSFM includes 131,192 separate polygons in 29 geomorphic feature categories, used here to assess differences between passive and active continental margins as well as between 8 major ocean regions (the Arctic, Indian, North Atlantic, North Pacific, South Atlantic, South Pacific and the Southern Oceans and the Mediterranean and Black Seas). The GSFM provides quantitative assessments of differences between passive and active margins: continental shelf width of passive margins (88 km) is nearly three times that of active margins (31 km); the average width of active slopes (36 km) is less than the average width of passive margin slopes (46 km); active margin slopes contain an area of 3.4 million km2 where the gradient exceeds 5°, compared with 1.3 million km2 on passive margin slopes; the continental rise covers 27 million km2 adjacent to passive margins and less than 2.3 million km2 adjacent to active margins. Examples of specific applications of the GSFM are presented to show that: 1) larger rift valley segments are generally associated with slow-spreading rates and smaller rift valley segments are associated with fast spreading; 2) polar submarine canyons are twice the average size of non-polar canyons and abyssal polar regions exhibit lower seafloor roughness than non-polar regions, expressed as spatially extensive fan, rise and abyssal plain sediment deposits – all of which are attributed here to the effects of continental glaciations; and 3) recognition of seamounts as a separate category of feature from ridges results in a lower estimate of seamount number compared with estimates of previous workers. Reference: Harris PT, Macmillan-Lawler M, Rupp J, Baker EK Geomorphology of the oceans. Marine Geology.
Critical to the successful implementation of EBM in the Arctic is the existence of a cohesive circumpolar approach to the collection and management of data and the application of compatible frameworks, standards and protocols that this entails. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/marine" target="_blank">Chapter 2</a> - Page 29 - Box Figure 2.2
Harvest marine mammal Focal Ecosystem Component stocks in Arctic Marine Areas. Harvested without quotas, with quotas or not harvested. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/findings/marine-mammals" target="_blank">Chapter 3</a> - Page 158 - Figure 3.6.4
Trends in abundance of marine mammal Focal Ecosystem Components across each Arctic Marine Area. STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - Chapter 4 - Page 182 - Figure 4.6
A total of 95 areas of heightened ecological significance have been identified within the Arctic LMEs. The areas were identified primarily on the basis of their ecological importance to fish, birds and/or mammals, as these species are the most widely studied Arctic groups. The majority of areas identified are used by birds (85) and marine mammals (81), with a lower number used by fish (40, most of them spawning areas). About 70 areas are used both by birds and mammals, and only two of the areas identified are used only by fish.The areas of heightened ecological significance comprise a total area of about 12 million km2, or more than half the total area of the ice-covered part of the marine Arctic. The areas are generally not homogenous but comprise subareas used by fish, birds or mammals. Based on the approach used, subareas were identified separately for fish, birds, and mammals, or information on the use of the larger areas by these groupswas summarized. The subareas often overlap and are also often used by two or more species of birds or mammals, such as for breeding in seabird colonies or for staging by waterfowl and shorebirds. Information on species present and the times and purposes of use are given in summary tables for each LME. Thus, while the areas identified as being of heightened ecological significance cover a large total area, this is the aggregate area used over all seasons throughout the year. The area used at any one time is lower due to the strong seasonal pattern in the annual migratory cycles of fish, birds and mammals.
Some features of the sea ice environment. Marine areas seasonally or permanently covered by sea ice are a globally unique habitat. Ice edges and open water areas favour wind-driven mixing of the seawater that enhances local production and can create biological hotspots. Adapted from Eamer et al. (2013). STATE OF THE ARCTIC MARINE BIODIVERSITY REPORT - <a href="https://arcticbiodiversity.is/marine" target="_blank">Chapter 2</a> - Page 20 - Box Fig 2.1