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Antarctic Marine Biodiversity: Adaptations, Environments and Responses to Change
Published in S. J. Hawkins, A. J. Evans, A. C. Dale, L. B. Firth, I. P. Smith, Oceanography and Marine Biology, 2018
Seabed patchiness in shallow water is primarily caused by variations in ice impacts (Barnes & Conlan 2012). Average annual wind speeds are highest globally in the latitudes between 50°S and 70°S, reaching values around 10 m s−1, and average oceanic wave heights are also the largest in these latitudes at around 4 m (Barnes & Conlan 2007). These factors combine with the presence of ice in its many forms to make the shallow Southern Ocean seabed massively disturbed and only the most human-impacted seabeds due to trawling approach these levels of disturbance (Barnes & Conlan 2012). At depths of around 10–15 m, a site in North Cove, Rothera Point on Adelaide Island, Antarctic Peninsula was monitored for iceberg impacts, and over 90% of the site was impacted within one year, with several areas in the study experiencing multiple impacts. In another nearby bay, however, only around 40% of the area monitored was impacted per year (Brown et al. 2004). Shallower exposed sites are impacted more often. Other forms of ice also have strong effects on shallow benthos, with anchor ice growing from cold seabed extending down to 30 m depth at the highest latitudes. An ice foot often forms in the shallowest 2–3 m depth that can be several metres thick and persists for much of the year in some sites (Barnes & Conlan 2007).
Environmental Influences on the Distribution and Composition of Wetlands in the Great Lakes Basin
Published in Harold H. Prince, Frank M. D’Itri, Coastal Wetlands, 1985
A zone of grounded ice linking the shoreline to the ice pack and incorporating frozen sediments occurs consistently along the St. Lawrence River. It may extend 40 to 50 meters outward from wetlands in protected bays and 5 to 10 meters outward along rocky shorelines where bottom gradients are steeper. This ice foot zone forms initially through direct freezing of exposed bottoms and later through the accumulation of ice and snow as the winter progresses.
Assessing bank erosion hazards along large rivers in the Anthropocene: a geospatial framework from the St. Lawrence fluvial system
Published in Geomatics, Natural Hazards and Risk, 2021
Jean-François Bernier, Léo Chassiot, Patrick Lajeunesse
In contrast to the RS wetlands, results show that tidal marshes are the most sensitive riverbank type of the FES, with 58% showing GI of erosion and with continuous segments up to 3.2 km with an erosive tidal cliff (Figures 6(B) and 7(B)). The majority of these segments with a high EI are located in the channel north of Île d’Orléans (Figure 12(B)). In this sector, erosion results from the joint action of storm surges, anthropogenic pressure, ice foot duration, tidal cycles and relative sea level fluctuations (Forbes and Taylor 1994; Argus Groupe-Conseil 1996; Bernatchez and Dubois 2006; Drapeau 2007; Bhiry et al. 2013). The suspension of eroded fine sediments linked with tidal range maximum close to 6 m make the northern arm of Île d’Orléans, especially Cap Tourmente mudflats, the most dynamic area of the FES (Sérodes 1980). Located in a fetch-limited environment (<50 km), these marshes are less exposed to high-energy wind, but wind-generated waves remain the primary mechanism of tidal marsh shoreline change (Houser 2010; Nordstrom and Jackson 2012; Prahalad et al. 2015). Low-energy waves could also impact marshes, especially after a storm-induced breach in the vegetation cover (Prahalad et al. 2015). Bhiry et al. (2013) monitored tidal marshes in the FES and have also observed that the height of a marsh tidal cliff greatly influences the rate of retreat, i.e. the higher the slope, the greater the rate of retreat.
A novel statistical model for flood prediction in the Eel River watershed, New Brunswick, Canada
Published in Water Science, 2023
Ali Faghfouri, Achraf Hentati, Guillaume Fortin, Daniel Germain
Climate change can induce local variability in the amount, duration, frequency, and distribution of precipitations which causes a change in flooding regimes (Gaur, Gaur, & Simonovic, 2018; Mladjic et al., 2011). In the summertime, warming of the Atlantic Ocean related to global warming impacts the Atlantic provinces such as NB by producing more hurricanes or stronger ones. Hurricanes eventually diminish in intensity as they make landfall and become post-tropical storms that bring intense rainfall and damaging winds causing major flooding to the southern part of the province of NB. Also, due to the complex system of storm-flooding, prediction and tracking of these events might become more difficult (Collins et al., 2014). Climate change could also alter the hydrologic cycle and its components (physical parameters) so this study will be helpful to improve the knowledge of how flood patterns could be affected by climate change in NB for the future time frame. Coastal flooding is expected to increase in many parts of the province (e.g. the Eel River watershed) because of rising sea levels. Environmental changes need to be integrated not only at local sea levels but also into the global sea-level rise and local land uplift or subsidence. Local sea level is predicted to rise and increase flooding, in most parts of the Atlantic, and Pacific coasts of Canada and the Beaufort coast in the Arctic, where the land is subsiding or slowly uplifting. The loss of sea ice in Atlantic Canada and the Arctic further increases the risk of damage to coastal infrastructures and ecosystems due to the larger storm surges and waves (Bush & Lemmen, 2019; McGrath, Stefanakis, & Nastev, 2015) and the absence of an ice foot on the coast. This issue must be considered for analyzing floods in NB because most of the large rivers (e.g. the Eel River) that end their course in the Atlantic Ocean or the Gulf of St. Lawrence are tidally influenced.