Vulnerability assessment of nearshore clam habitat subject to storm waves and surge

Abstract

Present work studied the lesion mechanism of coastal clam and its vulnerability assessment subject to the hydrodynamic disturbance of extreme storm events. A clam habitat at the northeast coast of China was chosen for the demonstration study. Relocation failure after passive transport due to excessive substrate erosion or suffocation in anoxic burial under overburdening sedimentation was identified the major cause of negative biomass responses during the storm. Based on the biological propensity and physiological sensitivity of the clam, a tunable loss probability function correlating the mortality with the shell length and the seabed change was proposed. A hydrodynamic model was then adopted to compute the sediment transport and net changes in the seafloor in response to the comprehensive process of storm waves and surge. The spatial distribution of the damage states was evaluated based on the numerical results incorporating the loss probability function. The estimated damage was mainly concentrated along the wave shoaling and breaking belts parallel to the shoreline. High surge levels pushed the “damage belt” shoreward, in which case large waves were able to propagate close to the shoreline before breaking. The scientific findings are helpful to better understand the vulnerability of the clam habitat to the storm disturbance. The study result as well provides a practical methodology of the storm risk assessment for benthic communities in broader ecological and geophysical scopes. The methodology are expected to be further validated and improved by more widespread sampling on coastal ecosystem or mariculture that will withstand future storms.

Seasonal Shift in Storm Surges at Brest Revealed by Extreme Value Analysis

“…Detecting shifts in the storm surge season can be important, as storm surges and waves greatly impact the ecosystems. Storm events can increase mortality of benthic species, due to movements (i.e., erosion, deposition) of the substratum where the benthos live (Zhang et al, 2021). For the south of the North Sea, Nehls and Thiel (1993) reported that the number of mussel beds were divided by nearly two between 1989 and 1990, due to severe storms in early 1990.…”

“…For the Gulf of Mexico, Posey et al (1996) reported that one third of benthic fauna exhibited a significant decline after a severe storm. Along the coasts of China, Zhang et al (2021) reported strong mortality of shellfish (clams) during storms. These studies underline the vulnerability of benthic species to storm events.…”

Shoreline change dynamics along the Augusta coast, eastern Sicily, South Italy

“…Around 60% of the world's population that lives in coastal areas is vulnerable to erosional phenomena (Cai et al, 2009; Wang et al, 2021; Zhang et al, 2021). Coastal morphology is modelled by the interaction between sediment budget and physical oceanographic conditions (Cao et al, 2020; Distefano & Gamberi, 2022; Laksono, Widagdo et al, 2022; Todd et al, 2019).…”