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Banana is often grown in coastal-regions, and while known for its sensitivity towards seawater, little is documented on the effect of sea-salt on the growth, physiology and metal homeostasis. Here we report that banana plantlets exposed to sea-salt at extreme (average seawater concentration; 52.7 dS m−1), severe (28.5 dS m−1) or moderate (10.2 dS m−1) salinity levels had reduced root length (2.0–6.0-fold), plant height (1.2–1.6-fold), leaf number (2.0–2.3-fold) and leaf area (3.3–4.0-fold) compared to control plantlets. Degradation of pigments (total chlorophyll: 1.3–12.3-fold, chlorophyll a: 1.3–9.2-fold; chlorophyll b: 1.3–6.9-fold lower and carotenoids: 1.4–3.7-fold lower) reflected vulnerability of photosystems to salt stress. Relative water content showed a maximum decrease of 1.5-fold in salt stress. MDA analysis showed sea-salt exposure triggers 2.3–3.5-fold higher lipid peroxidation. Metal content analysis showed a 73-fold higher Na value from roots exposed to extreme salinity compared to control plantlets. While phenotype was clearly affected, moderate salinity showed no significant alteration of macro (N, P, K and Ca) and micro (Fe, Mn and Cu) metal content. The antioxidant enzymes: SOD (3.2-fold), CAT (1.7-fold) and GR (6-fold) showed higher activity at moderate salinity level compared to control plantlets but lower activity at severe (SOD: 1.3-fold; CAT: 1.5-fold; GR: 2-fold lower) and extreme seawater salinity (SOD: 1.5; CAT: 1.9; GR: 1.3-fold lower). Mild changes in growth and physiology at sea-salt levels equivalent to moderate seawater flooding, indicate that banana will survive such flooding, while extreme seawater inundation will be lethal. This data provides a reference for future salinity-mediated work in banana. [ABSTRACT FROM AUTHOR]

Storm Xynthia crossed France’s western coast between 28th February and 1st March 2010. It hit the Vendée and Charente-Maritime departments hardest, as storm surge flooded up to 23,000 ha of coastal agricultural areas (i.e. polders), causing severe damage to farming operations. However, farm-level damage in the aftermath of seawater flooding is an issue that has rarely been explored in the literature. Here we investigated the effects of storm Xynthia on agriculture at the farm scale. We focused on the case study of Saint Laurent de la Prée research farm, a mixed crop-livestock system that was severely hit. All damages were described and economic losses were quantified for the years 2010 and 2011. The results show numerous consequences of the storm in terms of crop and fodder production losses, but also farm infrastructure repairs, crop restoration and animal health problems. Economic damage costs were high, reaching €71,720 in 2010 (€500/ha flooded) and €56,195 (€390/ha) in 2011 for the case study farm. The discussion highlights the farm-level impacts of seawater flooding and the crucial factors that can explain the damage caused to agriculture by storm events in coastal areas. The results are also discussed in the wider context of global warming which is expected to cause sea level rise and more frequent storm events in the future. The vulnerability of coastal agricultural areas to storms thus exposes broader issues of coastal flooding risk management and specifically the allied protection-remediation-adaptation measures. The conclusions underline the need for future research to address prospective scenarios and subsequent adaptive strategies. [ABSTRACT FROM AUTHOR]

An unprecedented set of hydrologic observations was collected after the Dec 2008 seawater-flooding event on Roi-Namur, Kwajalein Atoll, Republic of the Marshall Islands. By two days after the seawater flooding that occurred at the beginning of dry season, the observed salinity of water withdrawn by the island’s main skimming well increased to 100% seawater concentration, but by ten days later already decreased to only 10–20% of seawater fraction. However, the damaging impact on the potability of the groundwater supply (when pumped water had concentrations above 1% seawater fraction) lasted 22 months longer. The data collected make possible analyses of the hydrologic factors that control recovery and management of the groundwater-supply quality on Roi-Namur and on similar low-lying islands. With the observed data as a guide, three-dimensional numerical-model simulation analyses reveal how recovery is controlled by the island’s hydrology. These also allow evaluation of the efficacy of basic water-quality management/mitigation alternatives and elucidate how groundwater withdrawal and timing of the seawater-flooding event affect the length of recovery. Simulations show that, as might be expected, by adding surplus captured rainwater as artificial recharge, the freshwater-lens recovery period (after which potable groundwater may again be produced) can be shortened, with groundwater salinity remaining lower even during the dry season, a period during which no artificial recharge is applied. Simulations also show that the recovery period is not lengthened appreciably by groundwater withdrawals during recovery. Simulations further show that had the flooding event occurred at the start of the wet season, the recovery period would have been about 25% (5.5 months) shorter than actually occurred during the monitored flood that occurred at the dry-season start. Finally, analyses show that artificial recharge improves freshwater-lens water quality, making possible longer use of groundwater as a water supply throughout each year, even when no seawater flooding has occurred. [ABSTRACT FROM AUTHOR]

Jeong, Y.H.; Lee, S.Y.; Lee, J.; Lee, T.K., and Lee, W.D., 2021. Characteristics of seawater intrusion in coastal aquifers due to seawater flooding: A numerical study. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 96–100. Coconut Creek (Florida), ISSN 0749-0208. In typical coastal aquifers, dense brine infiltrates under freshwater in a wedge form. However, during seawater flooding due to storm surges or tsunamis, dense brine infiltrates from the surface into the ground. In this study, to investigate the characteristics of seawater intrusion in coastal aquifers. we simulated seawater intrusion by seawater flooding using the Navier–Stokes solver based on the porous body model. The numerical analysis results showed that when the hydraulic gradient of the coastal aquifers was small, salt diffusion by seawater flooding occurred throughout the groundwater, and the infiltrated seawater remained in the freshwater layer for a long time. However, when the hydraulic gradient of the coastal aquifers was large, the salt damage by seawater flooding was relatively small, and the amount of infiltrated seawater that escaped into the sea through the groundwater flow increased. In other words, a larger hydraulic gradient of coastal aquifers leads to a lower salt diffusion in the groundwater by seawater flooding and a faster recovery. The results of this study will be useful for the preservation of coastal aquifers in the event of tsunamis and flooding. [ABSTRACT FROM AUTHOR]