Salinization effects on coastal ecosystems: a terrestrial model ecosystem approach

Abstract

In coastal areas, intrusion/irrigation with seawater can threaten biodiversity along with crop yields, and the leaching of salts from areas affected by these processes can increase the salinity of water bodies nearby. The aims of this study were to evaluate the effects of salinization on coastal soil ecosystems due to saline intrusion/irrigation. Terrestrial model ecosystems were used to simulate two soil salinization scenarios: (i) seawater intrusion and irrigation with distilled water and (ii) seawater intrusion and irrigation with saline water. Three sampling periods were established: T0—after acclimation period; T1—salinization effects; and T2—populations' recovery. In each sampling period, the abundance of nematodes, enchytraeids, springtails, mites and earthworms, and plant biomass were measured. Immediate negative effects on enchytraeid abundance were detected, especially at the higher level of saltwater via intrusion+irrigation. Eight weeks after the cessation of saline irrigation, the abundance of enchytraeids fully recovered, and some delayed effects were observed in earthworm abundance and plant biomass, especially at the higher soil conductivity level. The observed low capacity of soil to retain salts suggests that, particularly at high soil conductivities, nearby freshwater bodies can also be endangered. Under saline conditions similar to the ones assayed, survival of some soil communities can be threatened, leading to the loss of biodiversity. This article is part of the theme issue ‘Salt in freshwaters: causes, ecological consequences and future prospects’.

Assess Effectiveness of Salt Removal by a Subsurface Drainage with Bundled Crop Straws in Coastal Saline Soil Using HYDRUS-3D

“…By flooding with a large amount of water, solute salt from the soil above the subsurface pipes was leached and finally discharged through the drainage pipe, which keeps the saline water table under a critical depth. However, the desalination capacity of subsurface drainage largely depend on the quality of the leaching water and it is unsustainable to employ a very large amount of freshwater for leaching practices since the coastal area is also facing the shortage of fresh water due to seasonal seawater intrusion and pollutants emission from human activities [6]. In recognition of this fact, desalinated or diluted seawater could be adopted as an abundant and steady water source to remove the hydrological constraints for soil leaching during the reclamation process of the coastal area [7].…”

Salt in freshwaters: causes, effects and prospects - introduction to the theme issue

“…For example, seawater intrusion will expose aquatic and terrestrial organisms to high NaCl concentrations in coastal areas, and their potential response remains largely unexplored. In this issue, Pereira et al [63] and Venâncio et al [64] show that increased salinity can considerably affect aquatic organisms (especially cyanobacteria and zooplankton), but may have little effect on soil organisms.…”

Geographical origin determines responses to salinity of Mediterranean caddisflies

“…Also, we expect that organisms adapted to higher salinity levels will reduce their survival under low salinity. On the other hand, several studies indicate that freshwater organisms are negatively affected by increased salinity [28,29]. According to this hypothesis, we would expect that low-salinity adapted organisms will be more affected by higher salinity levels both in behavioral responses and survival, as compared to organisms adapted to higher salinity levels.…”