Elevated Salinity Levels Research Articles

Maximizing leaf carbon gain in varying saline conditions: An optimization model with dynamic mesophyll conductance

While the adverse effects of elevated salinity levels on leaf gas exchange in many crops are not in dispute, representing such effects on leaf photosynthetic rates (A) continues to draw research attention. Here, an optimization model for stomatal conductance (gc ) that maximizes A while accounting for mesophyll conductance (gm ) was used to interpret new leaf gas exchange measurements collected for five irrigation water salinity levels. A function between chloroplastic CO2 concentration (cc ) and intercellular CO2 concentration (ci ) modified by salinity stress to estimate gm was proposed. Results showed that with increased salinity, the estimated gm and maximum photosynthetic capacity were both reduced, whereas the marginal water use efficiency λ increased linearly. Adjustments of gm , λ and photosynthetic capacity were shown to be consistent with a large corpus of drought-stress experiments. The inferred model parameters were then used to evaluate the combined effects of elevated salinity and atmospheric CO2 concentration (ca ) on leaf gas exchange. For a given salinity level, increasing ca increased A linearly, but these increases were accompanied by mild reductions in gc and transpiration. The ca level needed to ameliorate A reductions due to increased salinity is also discussed using the aforementioned model calculations.

Effects of road salt on microbial communities: Halophiles as biomarkers of road salt pollution.

Increased use of salting to de-ice roadways, especially in urban areas, is leading to elevated salinity levels in soil as well as surface- and ground water. This salt pollution may cause long-term ecological changes to soil and aquatic microbial communities. In this study, we examined the impact on microbial communities in soils exposed to urban road salt runoff using both culturing and 16S amplicon sequencing. Both methods showed an increase in halophilic Bacteria and Archaea in samples from road salt-exposed areas and suggested that halophiles are becoming persistent members of microbial communities in urban, road salt-impacted soils. Since salt is a pollutant that can accumulate in soils over time, it is critical to begin assessing its impact on the environment immediately. Toward this goal, we have developed a facile semi-quantitative assay utilizing halophilic microbes as biomarkers to evaluate on-going salt pollution of soils.

Salinity Tolerance and Recovery Attributes of Warm-season Turfgrass Cultivars

As population growth places greater pressures on potable water supplies, nonpotable recycled irrigation water is becoming widely used on turfgrass areas including golf courses, sports fields, parks, and lawns. Nonpotable recycled waters often have elevated salinity levels, and therefore turfgrasses must, increasingly, have good salinity tolerance to persist in these environments. This greenhouse study evaluated 10 commonly used cultivars representing warm-season turfgrass species of bermudagrass (Cynodon spp.), zoysiagrass (Zoysia spp.), st. augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], and seashore paspalum (Paspalum vaginatum Swartz) for their comparative salinity tolerance at electrical conductivity (EC) levels of 2.5 (control), 15, 30, and 45 dS·m–1. Salinity treatments were imposed on the grasses for 10 weeks via subirrigation, followed by a 4-week freshwater recovery period. Attributes, including turf quality, the normalized difference vegetation index (NDVI), canopy firing, and shoot biomass reductions were evaluated before and after salinity stress, as well as after the 4-week freshwater recovery period. Results showed considerable differences in salinity tolerance among the cultivars and species used, with the greatest tolerance to elevated salinity noted within seashore paspalum cultivars and Celebration® bermudagrass. In comparison with growth in 2.5-dS·m–1 control conditions, increased shoot growth and turf quality were noted for many bermudagrass and seashore paspalum cultivars at 15 dS·m–1. However, st. augustinegrass and some zoysiagrass cultivars responded to elevated salinity with decreased growth and turf quality. No cultivars that had been exposed to 30- or 45-dS·m–1 salinity recovered to acceptable levels, although bermudagrass and seashore paspalum recovered to acceptable levels after exposure to 15-dS·m–1 salinity. More severe salinity stress was noted during year 2, which coincided with greater greenhouse temperatures relative to year 1.

Salt tectonism and distribution of brackish-water trace fossils in the Cretaceous McMurray Formation, Athabasca Oil Sands, Alberta Foreland Basin

A proposed salt tectonism-saline seep model provides a novel alternative to the two widely accepted but irreconcilable depositional models for middle McMurray Formation strata of the Lower Cretaceous Athabasca Oil Sands deposit. Established interpretations of a fluvial axial channel belt along the eastern Alberta Foreland Basin contrast with a hundreds-of-kilometres long estuarine marine–fluvial transition zone setting that was characterized by brackish-water trace fossil laden beds. The architecture of a highly sinuous fluvial meander channel belt with bank-full depths of 30–40 m furthermore is not compatible with an estuary having a tens-of-metres thick salt wedge extending hundreds-of-kilometres upstream. This new model proposes that the removal of the underlying 100 m thick Middle Devonian salt section occurred across thousands of square kilometres and resulted in voluminous saline seeps up-section into river channel fills of the middle McMurray Formation. Southward transgression by a Boreal Sea tongue terminated fluvial lower McMurray Formation deposition, and transported brackish-water larvae inland along the tide-impacted backwater length. This zoology was sustained along the fluvial channel belt by the saline seeps that elevated salinity levels in channel muds as the fluvial system dominance reasserted. Brackish-water macroinvertebrates rapidly adapted to new terrestrial food sources in these fluvial channels, precluding the necessity for a salt wedge to have extended inland for hundreds of kilometres. This research presents the first quantitative analysis of the McMurray Formation trace fossil distribution patterns. Quaternary saline surface seep trends are proposed to represent intermittent seepage up-section since the Early Cretaceous.

Evaluation of subtropical ornamental trees for reclaiming salinity affected lands

This study was conducted to evaluate the tolerance of 1-year-old seedlings of ten subtropical ornamental tree species against a range of salinity levels of NaCl from May 2015 to October 2015. The levels were further enhanced from November to April 2017 as 100% survival was observed in the initial concentrations for all species. The seedlings were grown during the first week of April 2015 in 10″ earthen pots containing soil: farmyard manure (2:1), irrigated with tap water for 1 month followed by saline irrigation in May by maintaining electrical conductivity at 0.75, 1.00, 1.25, 1.50, 2.25, and 3.00 dS/m for 30, 40, 50, 60, 90, and 120 mM NaCl. Every 3 months, heights, relative leaf water content, and percent survival were determined; total soluble sugars of the upper leaves of each tree were quantified. All species exhibited consistent early growth and survival when supplied with 30, 40, 50 and 60 mM of NaCl. Koelreutaria paniculata, Ficus benjamina, Putranjiva roxburghii, Bauhinia purpurea and Millettia ovalifolia were sensitive to elevated salinity levels and did not survive at the highest salt concentrations of 90 and 120 mM.

Response of Four Shrub Species to Different Water Source Components in an Arid Environment

Shrubland species in the Great Basin (USA) depend on soil water recharged from precipitation and/or groundwater for survival and growth. Climate warming and possible basin water diversion could alter the amount and timing of water availability to these plants. The objective of this study was to quantify the extent to which each of four co-occurring shrub species, big sage [Artemisia tridentata], rabbitbrush [Ericameria nauseosus], greasewood [Sarcobatus vermiculatus] and shadscale [Atriplex confertifolia)) acquired water from different sources (precipitation, soil vadose zone and/or groundwater) during a growing season. Soil salinity increased linearly with depth over the upper 1.5 m of soil, with salinity ranging from 0.84 to 31.70 dSm-1 in saturation extracts (R2=0.78, p<0.001). Changes in soil water both with depth and time during the growing period indicated that all species accessed soil water from precipitation recharge. Evapotranspiration totals for the growing period exceeded total precipitation by 137 mm, indicating that plants also used water stored deeper within the vadose zone and/or from groundwater (particularly) by the phreatophyte greasewood. Delta18O in the soil solution declined linearly with depth over the upper 100 cm (R2=0.80, p<0.001). Delta18O values in greasewood corresponded closely to Delta18O values measured deeper in the vadose zone and groundwater. Output from a mixing model indicated a decrease in groundwater reliance for greasewood from 30% in July to 2% in September, with a major shift to deeper soil water in the vadose zone (180 cm depth) (38% in July to 97% in September). Our data suggested that the four shrub species at our site were able to coexist because of their different spatial, temporal, and physiological uses of available soil water, reflecting possible water resource partitioning based on differences in response to precipitation, ability to extract water at deeper depths and variable tolerance to elevated levels of soil salinity to access groundwater.

Does salt source matter? Comparing growth of Hydrilla verticillata (L.f.) Royle and Vallisneria americana Michx. under elevated salinity levels induced by different salt sources

Does salt source matter? Comparing growth of Hydrilla verticillata (L.f.) Royle and Vallisneria americana Michx. under elevated salinity levels induced by different salt sources

Application of zeolite in removing salinity/sodicity from wastewater: A review of mechanisms, challenges and opportunities

Elevated salinity levels in wastewater usually have negative consequences to soil quality and crop growth if used directly in irrigation without proper treatment. Though many techniques have been developed to solve the problem, high capital costs or energy consumption have hindered their application in wider regions. One economical solution of reusing the wastewater of high salinity is applying natural or synthetic zeolites as ion exchanger and adsorbent. Chemically modified natural zeolites or synthetic zeolites have been utilized to reduce Na+ in various kinds of saline/sodic waters. In this paper, we reviewed the recent technical improvements of using natural or modified zeolites in the field of water salinity reduction. The mechanisms governing the salt removal process by zeolites are mainly ion exchange, adsorption, and salt storage. Factors such as zeolite's geochemical properties, pH, co-existing anions, concentration, valency, surface charge, and experimental conditions all influence the ion exchange process. Adsorption isotherm of Na+ ions on zeolites, mostly reported to follow either Langmuir or Freundlich isotherm, has a composition-dependent behaviour. The adsorption kinetics of Na+ on zeolites is mostly a pseudo-second-order type with an exothermic nature. Sodium removal by zeolites appears to be an effective water treatment technology for maximizing the beneficial use of poor-quality saline/sodic wastewater. However, challenges still remain and further work is required in areas of lowering operational cost and improving zeolite's regenerability. To overcome these challenges, researchers could make more efforts in technical improvements, including alterable surface properties and the incorporation of other approaches to achieve better salt removal outcome.

Responses of Four Rice Varieties to Elevated CO2 and Different Salinity Levels

Abstract: This study was carried out in 2014 at Isfahan University of Technology, Iran, to evaluate the responses of four rice varieties (Neda, Deylamani, Shiroudi and Domsorkh) to ambient (360 ± 50 μmol/mol) and elevated (700 ± 50 μmol/mol) air carbon dioxide (CO2) concentrations under four salinity levels (0, 30, 60 and 90 mmol/L NaCl). There was significant variation among rice varieties in response to elevated CO2 concentration under the four salinity levels. Under non-saline condition, elevated CO2 increased the dry weight of Neda, Deylamani and Domsorkh by 8%, 50% and 8%, respectively, but reversely decreased that of Shiroudi by 34%. Increasing CO2 concentration significantly reduced the negative effects of salinity on Shiroudi, but these effects were even increased in Deylamani and Domsorkh under all the salinity levels and in Neda only under 30 and 60 mmol/L NaCl. Significant correlations were established between plant dry weight, SPAD value and leaf area under both CO2 levels. However, this trend was observed only at ambient CO2 concentration in the presence of soluble carbohydrates. The results revealed the genotype and salinity dependence of the effects of CO2 concentrations on the rice traits investigated.

Hydrogeochemical and isotopic evaluation of groundwater with elevated arsenic in alkaline aquifers in Eastern Punjab, Pakistan

Geochemical investigation was carried out for delineating factors responsible for the mobilization of arsenic (As) from aquifer material into the groundwater. Four sites along Ravi River, (Samada, Sarai Chimba, Kot Maiga and Chah Fatehwala), were selected based on the blanket survey. Groundwater-rock interaction and evaporation were the key phenomena controlling groundwater chemistry, as shown by the hydrogeochemical data. Groundwater was predominantly Na-Cl type, with other principle facies being Na-HCO3, Na-Ca-HCO3 and Ca-Mg-Cl. The groundwater As concentration ranged between below detection level (2 μg/L) to 548 μg/L with 59% samples exceeding the World Health Organization (WHO) guidelines for As in drinking water (10 μg/L) and 31% having higher concentrations than the National Environmental Quality Standard (NEQS, 50 μg/L). Moderate to high concentrations of SO4−2 averaged at 244 mg/L and moderate NO3− concentrations averaged at 8 mg/L, together with alkaline pH (7.3–8.8) and high Eh values (113–402 mV) suggest partial oxidizing nature of the aquifers. The values for δ 18O and δ 2H in groundwater varied between −9.14 and −5.51‰, and −56.57 to −39.5‰ respectively, and suggests meteoric origin of the groundwater with some evaporative loss. This effect could be partly responsible for elevated levels of pH and salinity in groundwater. Based on geochemical and isotopic composition of groundwater, desorption of As from metal surfaces under alkaline environment might be the factor causing As enrichment in study area.

Disturbance-driven changes in fish assemblages caused by a sudden increase in salinity in a perennial desert stream

Disturbance is a key factor in structuring fish assemblages in rivers; characterizing reactions to disturbance is especially important in systems containing endangered species due to their vulnerability to extinction. A natural disturbance event occurred in the Virgin River in 1985, when normal flow patterns changed due to the appearance of a sinkhole upstream of the hot saline Pah Tempe Springs. This led to abnormally elevated levels of temperature and salinity that propagated downstream. We examined changes in fish assemblages at five sites in a 21 km reach downstream from the hot springs in the mainstem Virgin River, which were monitored monthly (with the exception of 1 site monitored biannually) between 1984 and 1987. Specifically, we compared the responses of the different fish species in space and time. Of the six native species investigated, speckled dace, spinedace, and the endangered woundfin experienced declines in abundance at sites closest to the disturbance. In contrast, Virgin River chub, another endangered species, experienced increases in abundance in sites nearest the disturbance, and desert sucker and flannelmouth sucker showed no change. Redundancy analysis confirmed that changes in assemblage structure were significant. Differential responses to the disturbance appeared to correlate with differences in feeding ecology, with insectivores being the most affected group. In terms of recovery, species with higher abundances in neighboring sites experienced faster recoveries than those with lower abundances. This study characterizes disturbance reactions in the Virgin River, and emphasizes the susceptibility of rare species to natural disturbances and subsequent depression of recolonization rates.

Changes In Antioxidant Enzyme Activity In Turfgrass Cultivars Under Various Saline Water Irrigation Levels To Suit Landscapes Under Arid Regions

ABSTRACTTurfgrass cover is an inevitable component in the urban landscapes of the United Arab Emirates. Tolerance to abiotic stress like salt, drought, and high temperature is a potential factor to be considered in the selection of turfgrass for the landscapes in the arid regions. Three Seashore paspalum genotypes, four Bermudagrass cultivars along with tall fescue as a control were screened for enzymatic changes under four different saline irrigation levels of 5,000, 10,000, 15,000, and 20,000 mg L−1 of salinity. Irrigation with potable water served as the control. Turfgrasses were maintained in a field experiment under factorial randomized block design for a period of two years under sustained saline conditions by working out the leaching fraction to maintain the precise level of salinity in each treatment throughout the experimental period. The activities of antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), polyphenol oxidase (PPO), and catalase (CAT) were assayed in each of the saline water treated turfgrass types. The SOD activity was found to be high in Yukon (bermudagrass) and Sea Dwarf paspalum. In the paspalum group, Salam and Sea Dwarf showed the highest SOD activity under saline condition. In Bermuda types, Yukon and SR 9554 showed the highest SOD activity compared to other bermuda types. Compared to other cultivars, Sea Isle 2000 (Paspalum type), SR 9554, and Yukon (Bermuda types) exhibited more APX activity without any significant differences among themselves. There was an elevated activity of POD initially, followed by gradual reduction upon increasing the salinity level. Salam cultivar maintained stable POD activity even at the elevated salinity levels. The paspalum types showed relatively high level of PPO activity compared to other types under salinity. Yukon cultivar showed a significantly higher activity of PPO when the salinity level was raised from 15,000 to 20,000 mg L−1. A significant increase with respect to CAT activity was exhibited in Sea Dwarf under elevated level of salinity. Saline water irrigation brought about a significant effect on the antioxidant enzyme systems to impart oxidative stress tolerance in turfgrass species.

Bacterial and Archaeal Diversity in Hypersaline Cyanobacterial Mats Along a Transect in the Intertidal Flats of the Sultanate of Oman.

Hypersaline intertidal zones are highly dynamic ecosystems that are exposed to multiple extreme environmental conditions including rapidly and frequently changing parameters (water, nutrients, temperature) as well as highly elevated salinity levels often caused by high temperatures and evaporation rates. Microbial mats in most extreme settings, as found at the coastline of the subtropical-arid Arabian Peninsula, have been relatively less studied compared to their counterparts around the world. We report, here, for the first time on the diversity of the bacterial and archaeal communities of marine microbial mats along an intertidal transect in a wide salt flat with strongly increased salinity employing Illumina MiSeq technology for amplicon sequencing of 16S rRNA gene fragments. Microbial communities were dominated by typical halotolerant to halophilic microorganisms, with clear shifts in community composition, richness, and diversity along the transect. Highly adapted specialists (e.g., Euhalothece, Salinibacter, Nanohaloarchaeota) were mainly found at the most extreme, upper tidal sites and less specialized organisms with wide tolerance ranges (e.g., Lyngbya, Rhodovibrio, Salisaeta, Halobacteria) in intermediate sites of the transect. The dominating taxa in the lower tidal sites were typical members of well-stabilized mats (e.g., Coleofasciculus, Anaerolineaceae, Thaumarchaeota). Up to 40% of the archaeal sequences per sample represented so far unknown phyla. In conclusion, the bacterial richness and diversity increased from upper towards lower tidal sites in line with increasing mat stabilization and functional diversity, opposed to that of cyanobacteria only and archaea, which showed their highest richness and diversity in upper tidal samples.

Chemical fingerprinting of saline water intrusion into sewage lines.

High salinity in sewage sludge can affect not only the operation of wastewater treatment plants (WWTPs) but also the quality of treated water generated, thereby limiting its downstream reuse. Using data on geochemical parameters, both for the central WWTP in Abu Dhabi, UAE, and literature values for potential regional saline water sources (e.g., shallow groundwater and regional Arabian Gulf seawater), a variety of chemical fingerprinting diagnostic ratios were calculated and plotted in order to determine the source of salinity in the municipal sewage. Data were compared with data from a regional WWTP that was not impacted by salinity. Monitoring data demonstrated persistently elevated levels of salinity in the municipal wastewater arriving at the central WWTP from the city. Dilution/concentration analysis using a conductivity vs. chloride plot showed both potential sources, i.e. Arabian Gulf seawater and coastal hypersaline groundwater, as feasible sources of wastewater salinization. Further diagnostic analysis using a Panno Plot indicated that coastal groundwater was the only likely source of salinization of municipal sewage. Additional confirmation of the identity of the source and the extent of mixing using different lines of evidence like stable isotope ratios is recommended for future study.

Chemical assessment of dam water irrigation effects on groundwater qualities in Bigherd plain, Fars Province, Iran

In this study the effect of irrigation by dam water in Bigherd area (Fars Province, Iran) on groundwater quality 1 and 3 years after dam construction was investigated. To conduct this study the major ion concentrations, including HCO3−, Ca2+, Mg2+, Na+, K+, SO42− and Cl− and water levels in ten water wells and the dam reservoir were measured during two periods (June 2009 and June 2011), analyzed by factor analysis and plotted in water quality charts. The results of factor analysis show that most of the dissolved ions including Mg2+, Ca2+, SO42−, Cl− and HCO3−, particularly in 2009, were mainly originated from carbonate and evaporitic formations as well as from the playa lake (Factor 1). In 2011, elevated salinity levels were found to be mainly related to intense evaporation during irrigation that are proportional to Na+ and K+ concentrations (Factor 2) and depend on the type of crop and irrigation method. It was also found that the surface waters from deeper origins had less of an effect on groundwater recharge compared to upstream carbonate aquifers.

Water quality, seasonality, and trajectory of an aquaculture-wastewater plume in the Red Sea

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 10:61-77 (2018) - DOI: https://doi.org/10.3354/aei00254 Water quality, seasonality, and trajectory of an aquaculture-wastewater plume in the Red Sea Aya Hozumi1,*, Pei-Ying Hong2, Stein Kaartvedt3, Anders Røstad1, Burton H. Jones1 1King Abdullah University of Science and Technology (KAUST), Red Sea Research Center (RSRC), Biological and Environmental Sciences & Engineering Division (BESE), Thuwal 23955, Saudi Arabia 2King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center, Biological and Environmental Sciences & Engineering Division (BESE), Thuwal 23955, Saudi Arabia 3Department of Biosciences, University of Oslo, 0316 Oslo, Norway *Corresponding author: aya.hozumi@kaust.edu.sa ABSTRACT: As aquaculture activity increases globally, understanding water mass characteristics of the aquaculture-wastewater plume, its nutrients, and its organic matter load and spatial distribution in the coastal recipient, is critical to develop a more sustainable aquaculture operation and to improve coastal management. We examined wastewater (estimated 42-48 m3 s-1) discharged from the largest aquaculture facility in the Red Sea and surveyed the area around the aquaculture outfall to characterize the biogeochemical properties of the wastewater plume and its spatial distribution. In addition, we assessed its associated microbial community structure. The plume was characterized by elevated levels of salinity, density, and turbidity, and traveled along paths determined by the bathymetry to form a dense, 1-3 m thick layer above the seafloor. The effluent was observed at least 3.8 km from the outfall throughout the year, but up to 8 km in early autumn. The total nitrogen concentration in the plume was more than 4 times higher than in surface waters 1.4 km from the outfall. High-throughput sequencing data revealed that bacterial and cyanobacterial communities significantly differed, and flow cytometry results showed that total cell counts were significantly higher at the outfall. Arcobacter, a genus associated with opportunistic pathogenic species (e.g. A. butzleri), was more abundant, while Prochlorococcus sp. was significantly less abundant at the outfall. This dense, bottom-flowing plume may have a detrimental impact on benthic and demersal communities. KEY WORDS: Anthropogenic effluent · Microbial biomarkers · Nutrification · Coastal management Full text in pdf format PreviousNextCite this article as: Hozumi A, Hong PY, Kaartvedt S, Røstad A, Jones BH (2018) Water quality, seasonality, and trajectory of an aquaculture-wastewater plume in the Red Sea. Aquacult Environ Interact 10:61-77. https://doi.org/10.3354/aei00254 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 10. Online publication date: February 19, 2018 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2018 Inter-Research.

Evaluating soil salinity and water management in Chaco Canyon, New Mexico

Previous studies in Chaco Canyon, New Mexico suggested that water management systems constructed during periods of increased aridity resulted in elevated salinity levels to the point that soils were no longer viable for growing cultigens. Salinity, pH, powder X-ray diffraction, and inductively coupled plasma atomic emission spectroscopy analyses of sediments and water collected from Chaco Canyon between the years 2013 and 2015 demonstrate conclusively that soils were suitable for the cultivation of maize by Ancestral Puebloans. Our findings clearly indicate that the salts are non-deleterious sulfate minerals. All of the cations and anions needed to form these minerals occur in the water of Chaco Canyon. Thus, increased soil salinity was not a critical factor in the abandonment of Chaco Canyon by Ancestral Puebloans. Sulfate and volcanogenic minerals increased soil fertility that allowed for the development and maintenance of an agricultural urban center in this dryland environment. Water management of sulfate and volcanic mineral rich soils created an environ ideal for maize agriculture. The occurrence of non-local Ancestral Puebloan maize in Chaco Canyon can be explained in terms of kinship mobility, the distance that goods and services move between extended families.

Investigation into the Potential use of Inland Saline Groundwater for the Production of Live Feeds for Commercial Aquaculture Purposes

Traditional agricultural methods and practices have rendered over 100 million hectares of land throughout the world, and over 5.7 million hectares in Australia, unsuitable for most forms of agriculture due to elevated salinity levels. Inland saline aquaculture is an adaptive approach to this environmental problem, and represents a potentially lucrative use for salt-affected land, with many economic, social and environmental benefits possible. Perhaps surprisingly, to date there has been relatively very little research conducted into the suitability (or otherwise) of inland saline aquaculture for the production of various species of microalgae and live feeds, which represent a crucial segment of the aquaculture industry. The key aim of this investigation was to test the hypothesis that all saline waters (natural sea water, artificial sea water and inland ground saline water) would produce uniform growth amongst the live feeds tested. This study expanded on the live feed species being tested to include Artemia (Artemia salina) rotifers (Brachionus plicatilis) and copepods (Cyclop ssp). While there were significant differences in the performance of all the tested live feed species, Nannochloropsis oculataand Brachionus plicatilisshowed better growth rates than those observed for natural seawater. It is hoped that these results can be used proactively by farmers seeking to diversify their crops to include the aquaculture of finfish in salt-affected areas of Australia and elsewhere.

Differences in impacts of Hurricane Sandy on freshwater swamps on the Delmarva Peninsula, Mid-Atlantic Coast, USA

Hurricane wind and saltwater surge may have different influences on the subsequent composition of forests. During Hurricane Sandy, while damaging winds were highest near landfall in New Jersey, inundation occurred along the entire eastern seaboard from Georgia to Maine. In this study, a comparison of damage from salinity intrusion vs. wind/surge was recorded in swamps of the Delmarva Peninsula along the Pocomoke (MD) and Nanticoke (DE) Rivers, south of the most intense wind damage. Hickory Point Cypress Swamp (Hickory) was closest to the Chesapeake Bay and may have been subjected to a salinity surge as evidenced by elevated salinity levels at a gage upstream of this swamp (storm salinity=13.1ppt at Nassawango Creek, Snow Hill, Maryland). After Hurricane Sandy, 8% of the standing trees died at Hickory including Acer rubrum, Amelanchier laevis, Ilex spp., and Taxodium distichum. In certain plots of Hickory, up to 25% of the standing trees were dead, corresponding with high soil salinity. The most important variables related to structural tree damage were soil salinity and proximity to the Atlantic coast as based on Stepwise Regression and NMDS procedures. Wind damage was mostly restricted to broken branches although tipped-up trees were found at Hickory, Whiton and Porter (species: Liquidamabar styraciflua, Pinus taeda, Populus deltoides, Quercus pagoda and Ilex spp.). These trees fell mostly in an east or east-southeast direction (88–107°) in keeping with the wind direction of Hurricane Sandy on the Delmarva Peninsula. Coastal restoration and management can be informed by the specific differences in hurricane damage to vegetation by salt vs. wind.

Induced production of brominated aromatic compounds in the alga Ceramium tenuicorne.

In the Baltic Sea, high concentrations of toxic brominated aromatic compounds have been detected in all compartments of the marine food web. A growing body of evidence points towards filamentous algae as a natural producer of these chemicals. However, little is known about the effects of environmental factors and life history on algal production of brominated compounds. In this study, several congeners of methoxylated polybrominated diphenyl ethers (MeO-PBDEs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and brominated phenols (BPs) were identified in a naturally growing filamentous red algal species (Ceramium tenuicorne) in the Baltic Sea. The identified substances displayed large seasonal variations in the alga with a concentration peak in July. Production of MeO-/OH-PBDEs and BPs by C. tenuicorne was also established in isolated clonal material grown in a controlled laboratory setting. Based on three replicates, herbivory, as well as elevated levels of light and salinity in the culture medium, significantly increased the production of 2,4,6-tribromophenol (2,4,6-TBP). Investigation of differences in production between the isomorphic female, male and diploid clonal life stages of the alga grown in the laboratory revealed a significantly higher production of 2,4,6-TBP in the brackish water female gametophytes, compared to the corresponding marine gametophytes. Even higher concentrations of 2,4,6-TBP were produced by marine male gametophytes and sporophytes.