Salinity Titration Protocol

The purpose of this resource is to measure the salinity of the water using a salinity titration kit. Students will measure the salinity of saltwater using a salinity titration kit. Educational levels: Primary elementary, Intermediate elementary, Middle school, High school

Differential Effects of Increasing Salinity on Germination and Seedling Growth of Native and Exotic Invasive Cordgrasses

Soil salinity is a key environmental factor influencing germination and seedling establishment in salt marshes. Global warming and sea level rise are changing estuarine salinity, and may modify the colonization ability of halophytes. We evaluated the effects of increasing salinity on germination and seedling growth of native Spartina maritima and invasive S. densiflora from wetlands of the Odiel-Tinto Estuary. Responses were assessed following salinity exposure from fresh water to hypersaline conditions and germination recovery of non-germinated seeds when transferred to fresh water. The germination of both species was inhibited and delayed at high salinities, while pre-exposure to salinity accelerated the speed of germination in recovery assays compared to non-pre-exposed seeds. S. densiflora was more tolerant of salinity at germination than S. maritima. S. densiflora was able to germinate at hypersalinity and its germination percentage decreased at higher salinities compared to S. maritima. In contrast, S. maritima showed higher salinity tolerance in relation to seedling growth. Contrasting results were observed with differences in the tidal elevation of populations. Our results suggest S. maritima is a specialist species with respect to salinity, while S. densiflora is a generalist capable of germination of growth under suboptimal conditions. Invasive S. densiflora has greater capacity than native S. maritima to establish from seed with continued climate change and sea level rise.Ministerio de Educación, Cultura y Deporte (FPU14/06556

Offsetting with Salinity Credits: An Alternative to Irrigation Zoning

Irrigation induced salinity is a serious problem in many countries around the world. In Australia, this type of salinity is most pronounced in the valley of the River Murray in South Australia. Location of irrigation enterprises has been identified as a key factor that needs to be taken into account by policies aimed at mitigating salinity. This article compares and contrasts two such policies: an irrigation zoning policy, where new irrigation enterprises are only allowed in low salinity impact zones, and an offsetting with salinity credits policy, where new irrigation enterprises can locate in high salinity impact zones, provided they offset their salinity impact with salinity credits. Key findings are that the offsetting policy will be both less costly and more effective in reducing salinity than a standalone irrigation zoning policy. This is due to the presence of incentives for choosing "optimal" location of irrigation enterprises when costs of salinity credits are taken into account.irrigation, least-cost, offsets, salinity, Land Economics/Use, Q15, Q18, Q25, Q50,

Quantitative RNA-seq Analysis Unveils Osmotic and Thermal Adaptation Mechanisms Relevant for Ectoine Production in Chromohalobacter salexigens

Quantitative RNA sequencing (RNA-seq) and the complementary phenotypic assays were implemented to investigate the transcriptional responses of Chromohalobacter salexigens to osmotic and heat stress. These conditions trigger the synthesis of ectoine and hydroxyectoine, two compatible solutes of biotechnological interest. Our findings revealed that both stresses make a significant impact on C. salexigens global physiology. Apart from compatible solute metabolism, the most relevant adaptation mechanisms were related to “oxidative- and protein-folding- stress responses,” “modulation of respiratory chain and related components,” and “ion homeostasis.” A general salt-dependent induction of genes related to the metabolism of ectoines, as well as repression of ectoine degradation genes by temperature, was observed. Different oxidative stress response mechanisms, secondary or primary, were induced at low and high salinity, respectively, and repressed by temperature. A higher sensitivity to H2O2 was observed at high salinity, regardless of temperature. Low salinity induced genes involved in “protein-folding-stress response,” suggesting disturbance of protein homeostasis. Transcriptional shift of genes encoding three types of respiratory NADH dehydrogenases, ATP synthase, quinone pool, Na+/H+ antiporters, and sodium-solute symporters, was observed depending on salinity and temperature, suggesting modulation of the components of the respiratory chain and additional systems involved in the generation of H+ and/or Na+ gradients. Remarkably, the Na+ intracellular content remained constant regardless of salinity and temperature. Disturbance of Na+- and H+-gradients with specific ionophores suggested that both gradients influence ectoine production, but with differences depending on the solute, salinity, and temperature conditions. Flagellum genes were strongly induced by salinity, and further induced by temperature. However, salt-induced cell motility was reduced at high temperature, possibly caused by an alteration of Na+ permeability by temperature, as dependence of motility on Na+-gradient was observed. The transcriptional induction of genes related to the synthesis and transport of siderophores correlated with a higher siderophore production and intracellular iron content only at low salinity. An excess of iron increased hydroxyectoine accumulation by 20% at high salinity. Conversely, it reduced the intracellular content of ectoines by 50% at high salinity plus high temperature. These findings support the relevance of iron homeostasis for osmoadaptation, thermoadaptation and accumulation of ectoines, in C. salexigens.España Ministerio de Economía y Competitividad BIO2015-63949-RJunta de Andalucía P11-CVI-729

Dynamics of a salinity-prone agricultural catchment driven by markets, farmers' attitude and climate change

An agent-based simulation model has been developed with CORMAS combining simplified bio-physical processes of land cover, dry-land salinity changes, rainfall, farm profitability and farmer decisions on land uses in a dry-land agricultural catchment (no irrigation). Simulated farmers formulate individual decisions dealing with land use changes based on the combined performance of their past land cover productivity and market returns. The willingness to adapt to market drivers and the ability to maximize returns varies across farmers. In addition, farmers in the model can demonstrate various attitudes towards salinity mitigation as a consequence of experiencing and perceiving salinity on their farm, in the neighborhood or in the entire region. Consequently, farmers can adopt land cover strategies aiming at reducing salinity impact. The simulation results using historical rainfall records reproduces similar trends of crop-pasture ratios, salinity change and farm decline as observed in the last 20 years in the Katanning catchment (Western Australia). Using the model as an explorative tool for future scenarios, the simulation results highlighted the importance of rainfall changes and wide-spread willingness of farmers to combat dry-land salinity. Rainfall changes as a consequence of climate change can lead to prolonged sequences of dry and wet seasons. Adaptation to these sequences by farmers seems to be critical for farm survival in this catchment. (Résumé d'auteur

Measuring the Long-Term Regional Benefits of Salinity Reduction

Approaches for evaluating salinity management benefits are generalized and extended to incorporate consideration of desalination and long-term changes in salinity concentration and water use patterns. Previous research indicates urban users incur the vast majority of salinity-related damages in affected regions, suggesting municipalities may benefit by considering mitigating actions independent of agriculture. However, previous studies have included no consideration of desalination. Earlier studies have also considered stepped increases in salinity, assuming a single future concentration when estimating the long-term benefits of salinity reduction, an approach inconsistent with the incremental nature of these increases. Long-term changes in water use patterns (urban vs. agricultural), when considered at all, have often been treated in the same stepwise fashion. For this analysis, a suitable region is selected and the benefits of a hypothetical salinity management program are estimated using the approach described. These results are then compared with those obtained through the use of several previous methods. Findings suggest that consideration of desalination and incremental variations in salinity and water use patterns can substantially lower the estimated benefits of regional salinity management programs.benefits, regional water resource modeling, salinity, water quality management, Resource /Energy Economics and Policy,

Spatiotemporal variability in the O-18-salinity relationship of seawater across the tropical Pacific Ocean

The relationship between salinity and the stable oxygen isotope ratio of seawater (δ18Osw) is of utmost importance to the quantitative reconstruction of past changes in salinity from δ18O values of marine carbonates. This relationship is often considered to be uniform across water masses, but the constancy of the δ18Osw-salinity relationship across space and time remains uncertain, as δ18Osw responds to varying atmospheric vapor sources and pathways, while salinity does not. Here we present new δ18Osw-salinity data from sites spanning the tropical Pacific Ocean. New data from Palau, Papua New Guinea, Kiritimati, and Galápagos show slopes ranging from 0.09 ‰/psu in the Galápagos to 0.32‰/psu in Palau. The slope of the δ18Osw-salinity relationship is higher in the western tropical Pacific versus the eastern tropical Pacific in observations and in two isotope-enabled climate model simulations. A comparison of δ18Osw-salinity relationships derived from short-term spatial surveys and multiyear time series at Papua New Guinea and Galápagos suggests spatial relationships can be substituted for temporal relationships at these sites, at least within the time period of the investigation. However, the δ18Osw-salinity relationship varied temporally at Palau, likely in response to water mass changes associated with interannual El Niño–Southern Oscillation (ENSO) variability, suggesting nonstationarity in this local δ18Osw-salinity relationship. Applying local δ18Osw-salinity relationships in a coral δ18O forward model shows that using a constant, basinwide δ18Osw-salinity slope can both overestimate and underestimate the contribution of δ18Osw to carbonate δ18O variance at individual sites in the western tropical Pacific.We are grateful for the dedicated water samplers who enabled this research: Lori J. Bell and Gerda Ucharm of the Coral Reef Research Foundation, Palau; Rosa Maritza Motoche Gonzalez and the Fuerza Aerea Ecuatoriana, Santa Cruz, Galapagos, Ecuador; Taonateiti Kabiri and the students of Tennessee Primary School, London, Kiritimati; and the Manus Weather Observers, U.S. Department of Energy ARM Climate Research Facility, Manus, Papua New Guinea. We would like to thank the Galapagos National Park, the Kiritimati Ministry of Environment Lands and Agricultural Development for sample permits, and the Charles Darwin Research Station for logistical support. Funding sources for this work includes NSF-AGS-PF 1049664 to J.L.C., NSF P2C2-1203785 to K.M.C., J.L.C., and D.N. This research was also supported by the Office of Biological and Environment Research of the U.S. Department of Energy as part of the Atmospheric Radiation Measurement Climate Research Facility. Isotope data are available as supporting information associated with the manuscript. (1049664 - NSF-AGS-PF; P2C2-1203785 - NSF; Office of Biological and Environment Research of the U.S. Department of Energy as part of the Atmospheric Radiation Measurement Climate Research Facility

Water calcium concentration modifies whole-body calcium uptake in sea bream larvae during short-term adaptation to altered salinities

Whole-body calcium uptake was studied in gilthead sea bream larvae (9–83·mg) in response to changing environmental salinity and [Ca2+]. Calcium uptake increased with increased fish size and salinity. Fish exposed to calcium-enriched, diluted seawater showed increased calcium uptake compared with fish in diluted seawater alone. Calcium uptake was unchanged in Na+- enriched, diluted seawater. Overall, [Ca2+], and not salinity/osmolarity per se, appears to be the main factor contributing to calcium uptake. By contrast, drinking was reduced by a decrease in salinity/osmolarity but was little affected by external [Ca2+]. Calculations of the maximum contribution from drinking-associated calcium uptake showed that it became almost insignificant (less than 10%) through a strong decrease in drinking rate at low salinities (0–8‰). Diluted seawater enriched in calcium to the concentration present in full-strength seawater (i.e. constant calcium, decreasing salinity) restored intestinal calcium uptake to normal. Extra-intestinal calcium uptake also benefited from calcium addition but to a lesser extent

Strategy of Nannochloropsis Against Environment Starvation: Population Density and Crude Lipid Contents

Nannochloropsis sp., an unicellular marine microalgae, has potential function as a food source for fish larvae and in chemical industry. Microenvironmental conditions, especially nitrogen and salinity stress in marine ecosystems, became major factor affecting the growth of Nannochloropsis sp.The aim of the experiment was to study effect of different salinities and nitrogen dosages to the growth and lipid contents of Nannochloropsis sp. cells.The experiment was arranged in factorial with three replicates. The first factor was salinity (28 ppt and 38 ppt), and the second factor was nitrogen dosage (100% and 50%). Results of the experiments indicated that nitrogen starvation and high saline concentration affected cell density of Nannochloropsis sp. in different level. The results showed that combination treatments of nitrogen starvation and salinity reduced cell density (treatmant A, B, and D), except in treatment C. Combination of high salinity and high N dosages resulted ini steady growth of Nannochloropsis sp. These results suggest that Nannochloropsis sp. are able to overcome salinity stress (38 ppt) in the presence of optimum concentration of nitrogen in the growth cultures.The results also shows that there were no significant differences of crude lipid content between treatments and no correlation between population density and crude lipid content. These results suggest that no simple correlation between population density and crude lipid concentration. On the other hand, population density was not the only factor affected crude lipid concentration in the microalgae cell

Behavioural effects of hypersaline exposure on the lobster Homarus gammarus (L) and the crab Cancer pagurus (L)

There is scarce existing information in the literature regarding the responses of any marine species, especially commercially valuable decapod crustaceans, to hypersalinity. Hypersaline discharges due to solute mining and desalination are increasing in temperate areas, hence the behavioural responses of the edible brown crab, Cancer pagurus, and the European lobster, Homarus gammarus, were studied in relation to a marine discharge of highly saline brine using a series of preference tests. Both species had a significant behavioural response to highly saline brine, being able to detect and avoid areas of hypersalinity once their particular threshold salinity was reached (salinity 50 for C. pagurus and salinity 45 for H. gammarus). The presence of shelters had no effect on this response and both species avoided hypersaline areas, even when shelters were provided there. If the salinity of commercial effluent into the marine environment exceeds the behavioural thresholds found here, it is likely that adults of these species will relocate to areas of more favourable salinity. In management terms it is advisable to ensure that any hypersaline discharges are limited to the lowest tolerance of all the economically valuable species in the area to avoid loss of revenue in fishery areas