| Title | Multi-decadal coastal evolution of a north Atlantic shelf-edge vegetated sand island - Sable Island, Canada |
| |
| Author | Eamer, J B R ;
Didier, D; Kehler, D; Manning, I; Colville, D; Manson, G; Jagot, A; Kostylev, V E |
| Source | Landscape and seascape responses to Canada's changing climate; Canadian Journal of Earth Sciences 2021 p. 1-14, https://doi.org/10.1139/cjes-2020-0194  Open
Access |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20200520 |
| Publisher | Canadian Science Publishing |
| Document | serial |
| Lang. | English |
| Media | paper; digital; on-line |
| File format | pdf; html |
| Province | Eastern offshore region; Nova Scotia |
| NTS | 10; 11 |
| Area | Sable Island |
| Lat/Long WENS | -60.2500 -59.5000 44.0833 43.8333 |
| Subjects | marine geology; surficial geology/geomorphology; environmental geology; geophysics; Nature and Environment; Science and Technology; continental margins; continental shelf; coastal environment; shoreline
changes; offshore islands; barrier islands; sands; dunes; climate effects; sea level changes; vegetation; remote sensing; photogrammetric surveys; airphoto interpretation; modelling; sediment transport; coastal erosion; oceanography; geological
evolution; Sable Island Bank; Climate change; marine beach sediments; Wind; Trends |
| Illustrations | location maps; geoscientific sketch maps; profiles; photographs; tables; aerial photographs; plots |
| Program | Climate Change Geoscience Coastal Infrastructure |
| Released | 2021 05 28 |
| Abstract | Impacts from a changing climate, in particular sea-level rise, will be most acutely felt on small oceanic islands. A common configuration of mid-latitude islands is the sandy barrier island. Sable
Island, Nova Scotia, Canada is a vegetated sand island near the shelf edge, 160 km from the nearest point of land, that is morphologically similar to a barrier island. This study uses 60 years of airphoto records to analyse changes in coastline
position through digitized shore and vegetation (foredune proxy) lines. Rates of coastal movement are analysed to model the future (2039) coastal configuration. The analyses suggest that the majority of the coastline on Sable Island is in retreat,
with net retreat on the south side of the island only partially offset by modest net advance on the north side. The different morphologies of the beach-dune systems of South Beach and North Beach, driven by incident wind and waves, yield these
different coastline responses. Projected loss of 10 ha by 2039 of the climax heath vegetative community to shoreline retreat suggests a trend toward island instability due to coastline migration. Island-wide data set trends show support for two
different but complementary hypotheses about whole-island evolution: (1) the island is mobile via bank migration driving southern coastline changes and experiencing sediment transport toward the east, or (2) the island is generally immobile and
losing subaerial sediments (and thus shrinking) likely due to ongoing (and accelerating) sea-level rise. |
| Summary | (Plain Language Summary, not published)
Sable Island is a small island composed almost entirely of sand located ~160 km from mainland Nova Scotia, Canada. Only a few tens of metres in elevation
at its highest point and at most 1.5 km wide at its widest, the island is particularly susceptible to sea-level rise and increased storminess. We used historical airphotos and modern digital imagery to look at how the shoreline evolved over the last
~60 years. We found that, in general, shorelines are retreating, particularly on the south-facing shoreline. Impacts on infrastructure are expected to occur within the next 20 years, and the stable heath vegetation community (and to a lesser extent
the rare freshwater ponds) will experience irreversible losses. The island as a whole may be either migrating northeastward or is more or less immobile and eroding. |
| GEOSCAN ID | 327523 |
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