Effect of cations on the removal rate of chloride ions and mechanism analysis in high-salt wastewater

The potential of different medicinal species as alternative crops for saline conditions needs to be explored. Comparative physiological responses of germinating seeds and mature plants of three genotypes of anise (Pimpinella anisum L.), fennel (Foeniculum vulgare Mill.), and ajwain (Trachyspermum ammi L.) to salt were studied in a 2-year field experiment using 0 and 100 mcM, and a laboratory experiment using 0, 25, 50, 75, 100, and 125 mM NaCl. Catalase and ascorbate peroxidase activities increased in the salt-stricken plants of all genotypes, but only peroxidase activity of the salt-treated plants of anise genotypes and two of the fennel genotypes increased under field conditions. Chlorophyll and K+ concentrations of all genotypes decreased, but proline and Na+ concentrations and Na+/K+ increased under saline conditions. Dry mass, grain yield, and essential oil yield decreased in the salt-exposed plants across all genotypes and species. Germination, root, and shoot length were suppressed upon exposure to saline water. Despite the increasing trend of the proline and polyphenol concentrations and catalase and peroxidases activities, ascorbate peroxidase activity of germinating seeds decreased with an increase in NaCl concentration. Smaller adverse effects of salt on fennel germination attributes, grain and essential oil yields were evident. Moreover, greater activities of antioxidative enzymes and maintained Na+ and Na+/K+ of salt-stricken fennel plants were observed. These findings indicate that germinating seeds and mature plants of fennel have a greater ability to withstand salinity than the other examined species.

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Fennel outperforms ajwain and anise in saline environment: physiological response mechanisms in germinating seeds and mature plants

The spread and cost of saltwater intrusion in the US Mid-Atlantic

Species-specific variation in response to stress is a key driver of ecological patterns. As climate change alters stress regimes, coastal plants are experiencing intensifying salinity stress due to sea-level rise and more intense storms. This study investigates the variation in species’ responses to presses and pulses of salinity stress in five glycophytic and five halophytic species to determine whether salinity intensity, duration, or their interaction best explain patterns of survival and performance. In salinity stress exposure experiments, we manipulated the intensity and duration of salinity exposure to challenge species’ expected salinity tolerances. Salinity intensity best explained patterns of survival in glycophytic species, while the interaction between intensity and duration was a better predictor of survival in halophytic species. The interaction between intensity and duration also best explained biomass and chlorophyll production for all tested species. There was interspecific variability in the magnitude of the interactive effect of salinity intensity and duration, with some glycophytic species (Persicaria maculosa, Sorghum bicolor, and Glycine max) having a more pronounced, negative biomass response. For the majority of species, prolonged stress duration exacerbated the negative effect of salinity intensity on biomass. We also observed an unexpected, compensatory response in chlorophyll production in two species, Phragmites australis and Kosteletzkya virginica, for which the effect of salinity intensity on chlorophyll became more positive with increasing duration. We found the regression coefficient of salinity intensity versus biomass at the highest stress duration, i.e., as a press stressor, to be a useful indicator of salinity tolerance, for which species’ salinity-tolerance levels matched those in the literature. In conclusion, by measuring species-specific responses to stress exposure, we were able to visualize the independent and interactive effects of two components of a salinity stress regime, intensity, and duration, to reveal how species’ responses vary in magnitude and by tolerance class.

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Distinguishing the Effects of Stress Intensity and Stress Duration in Plant Responses to Salinity

The effects of saltwater intrusion on germination success of standard and alternative crops

Food resources in marine food webs are often concentrated into patches within biological hotspots, separated by large expanses of barren ocean. Inhomogeneous, or “patchy” distribution of plankton is in part due to mesoscale and submesoscale oceanographic features transporting and locally concentrating plankton. Concentrations of plankton at the base of the food web increase prey availability for intermediate and upper trophic levels creating productive regions known as biological hotspots. Submesoscale oceanographic features within coastal biological hotspots occur at spatiotemporal scales that can be resolved by coastal High Frequency Radars (HFR). To identify areas with enhanced passive particle (plankton) transport and concentration, four popular mathematical techniques known as Coherent Structure Analyses (CSA) are applied to HFR observed ocean surface currents. Each CSA technique quantifies the stretching (pulling drifters apart) and shrinking (pushing drifters together) of the flow, yet each has its own unique calculation of “stretching” and “shrinking”. All four CSA have been applied to ocean datasets in previous studies, however results from the four techniques have not been compared and evaluated as valid ecological metrics in energetic coastal flows. The following study will bring clarity to what makes each type of coherent structure differ from the others when applied to plankton transport and concentration in a coastal marine ecosystem. Results show some coherent structures define boarders of transport while others define centers of attraction. The following study uses HFR observed surface currents around a known biological hotspot, Palmer Deep Antarctica to quantify prey concentrating ocean features, and describe their ecological significance by comparing them to biological observations. Transport features quantified by CSA have the potential to be transport hubs, delivering and concentrating constant supplies of plankton. Results have the potential to inform the identification of prey concentrating features in larger, more complex food webs, and expand the use of coastal HFR data.

Jacquelyn Veatch

Papers

The effects of saltwater intrusion on germination success of standard and alternative crops

High Frequency Radars as Ecological Sensors: Using Lagrangian Coherent Structures to Quantify Prey Concentrating Features