Stress ecology: interactive effect of temperature and salinity on early life stages of the barnacle, Amphibalanus improvisus

Marine Ecolog

Population and life-stage specific sensitivities to temperature and salinity stress in barnacles

Temperature and salinity shape the distribution and genetic structure of marine communities. Future warming and freshening will exert an additional stress to coastal marine systems. The extent to which organisms respond to these shifts will, however, be mediated by the tolerances of all life-stages and populations of species and their potential to adapt. We investigated nauplius and cypris larvae of the barnacle Balanus (Amphibalanus) improvisus from the Swedish west coast with respect to temperature (12, 20, and 28 °C) and salinity (5, 15, and 30) tolerances. Warming accelerated larval development and increased overall survival and subsequent settlement success. Nauplii developed and metamorphosed best at intermediate salinity. This was also observed in cypris larvae when the preceding nauplii stages had been reared at a salinity of 30. Direct comparisons of the present findings with those on a population from the more brackish Baltic Sea demonstrate contrasting patterns. We conclude that i) B. improvisus larvae within the Baltic region will be favoured by near-future seawater warming and freshening, that ii) salinity tolerances of larvae from the two different populations reflect salinities in their native habitats, but are nonetheless suboptimal and that iii) this species is generally highly plastic with regard to salinity

4-Aryl-4H-Naphthopyrans Derivatives: One-Pot Synthesis, Evaluation of Src Kinase Inhibitory and Anti-Proliferative Activities

Background: A series of 2-amino-4-aryl-4H-benzo[h or f]chromene-3-carbonitrile derivatives were synthesized and evaluated for inhibition of Src kinase and cell proliferation in breast carcinoma (BT-20) cell lines. Methods: The one-pot, three-component reaction of α or β-naphthol, malonitrile and an aromatic aldehyde in the presence of diammonium hydrogen phosphate was afforded the corresponding 2-amino-4-aryl-4H-benzo[h or f]chromene-3-carbonitrile derivatives, All target compounds were evaluated for inhibition of Src kinase and cell proliferation in breast carcinoma (BT-20) cell lines. Results: Among all tested compounds, unsubstituted 4-phenyl analog 4a showed Src kinas inhibitory effect with IC50 value of 28.1 μM and was the most potent compound in this series. In general, the compounds were moderately active against BT-20. 3-Nitro-phenyl 4e and 3-pyridinyl 4h derivatives inhibited the cell proliferation of BT-20 cells by 33% and 31.5%, respectively, and found to be more potent compared to doxorubicin (25% inhibition of cell growth). Conclusion: The data indicate that 4-aryl-4H-naphthopyrans scaffold has the potential to be optimized further for designing more potent Src kinase inhibitors and/or anticancer lead compounds

Being young in a changing world: how temperature and salinity changes interactively modify the performance of larval stages of the barnacle Amphibalanus improvisus

The fate of key species, such as the barnacle Amphibalanus improvisus, in the course of global change is of particular interest since any change in their abundance and/or performance may entail community-wide effects. In the fluctuating Western Baltic, species typically experience a broad range of environmental conditions, which may preselect them to better cope with climate change. In this study, we examined the sensitivity of two crucial ontogenetic phases (naupliar, cypris) of the barnacle toward a range of temperature (12, 20, and 28°C) and salinity (5, 15, and 30 psu) combinations. Under all salinity treatments, nauplii developed faster at intermediate and high temperatures. Cyprid metamorphosis success, in contrast, was interactively impacted by temperature and salinity. Survival of nauplii decreased with increasing salinity under all temperature treatments. Highest settlement rates occurred at the intermediate temperature and salinity combination, i.e., 20°C and 15 psu. Settlement success of “naive” cyprids, i.e., when nauplii were raised in the absence of stress (20°C/15 psu), was less impacted by stressful temperature/salinity combinations than that of cyprids with a stress history. Here, settlement success was highest at 30 psu particularly at low and high temperatures. Surprisingly, larval survival was not highest under the conditions typical for the Kiel Fjord at the season of peak settlement (20°C/15 psu). The proportion of nauplii that ultimately transformed to attached juveniles was, however, highest under these “home” conditions. Overall, only particularly stressful combinations of temperature and salinity substantially reduced larval performance and development. Given more time for adaptation, the relatively smooth climate shifts predicted will probably not dramatically affect this species

Sensitivity Analysis of AquaCrop Model for Winter Wheat in Different Water Supply Conditions

AquaCrop, a water-driven model, has been developed to simulate the response of crops, including wheat, to the amount of irrigation water. To estimate crop yield using this model, the calibration stage is applied first, employing the available data. Calibration accuracy guarantees the validation accuracy of this model. For this reason, before the calibration stage, the response of the AquaCrop model to changes in input parameters is investigated using sensitivity analysis. Most researchers use additive-subtractive methods. However, these methods do not provide much information about model sensitivity. In this research, three methods were used to analyze the sensitivity of AquaCrop to simulate winter wheat grain yield under different irrigation requirements. The methods included (1) an increasing-decreasing method; (2) a limit method; and (3) a Gamma test that was based on the nonlinear relationship between inputs and outputs. The irrigation treatments were 100%, 75%, 50%, and 0% of the irrigation requirement and were designated as I1, I2, I3, and I4. Six input parameters consisting of normalized water productivity (WP*), maximum crop coefficient for transpiration (KCTR), initial canopy cover (CCo), crop canopy growth coefficient (CGC), crop canopy decline coefficient (CDC) and harvest index (HI) were evaluated for sensitivity analysis. The results showed that the sensitivity of the AquaCrop model was extremely high to WP* changes and moderate to CCo changes. An inverse relationship between wheat grain yield and CDC and a direct relationship between wheat grain yield and other input parameters were observed. The sensitivity of the AquaCrop model to the CCo parameter was the same in all irrigation treatments. The increase in water stress decreased the sensitivity of the AquaCrop model to the input parameters. Therefore, in the case of large differences between simulated and observed grain yield, it is suggested to change WP* and Kctr values. In the condition of moderate difference, it is better to change two parameters, HI and CDC. To reduce the slight difference between the simulated and observed grain yield, it is suggested to change the two parameters, CGC and CCo. It should be noted that the results of the sensitivity analysis are specific to the experimental conditions, such as plant density, soil texture, and water supply, and may vary when applied to different regions. Therefore, it is recommended to obtain region-specific results and determine the sensitivity of the AquaCrop model to input parameters