Effects of temperature and salinity on survival and growth of the amphipod Hyale crassicornis (Gammaridea,Hyalidae)

This study explored the survival and growth of the marine amphipod Hyale crassicornis under different conditions of ambient temperature and salinity in the laboratory. In 96‐h exposure experiments at a salinity of 30, H. crassicornis tolerated temperatures between 6 and 28°C (>90% survival). The 96‐h LT₅₀ value (median lethal temperature) at high temperature range for the amphipod was 32°C. The values at low temperature range for adults and juveniles were 3.2 and 4.2°C, respectively, indicating that adults have a higher tolerance to low temperature than juveniles. At 25°C, the amphipods tolerated salinities between 10 and 50 (with >80% survival in 96?h). The 96‐h LS₅₀ values at high and low salinity ranges were 56 and 2, respectively. Growth of the juveniles from instars 1 to 6 was determined under different combinations of temperature and salinity. Growth rate of juveniles cultured at 25°C and a salinity of 20 was the highest (0.114?mm?day^?1) among the combinations of 15–25°C and 10–40 salinity. The moult increment of body length was affected by both temperature and salinity. Yet the intermoult duration of the amphipods was affected by temperature only but not by salinity.     

Temperature and high salinity effects in germinating dimorphic seeds of Atriplex rosea

Atriplex rosea L. (Chenopodiaceae; tumbling orach), an annual herb, is a widely established weedy species of disturbed sites in all counties of Utah. Seeds of Atriplex rosea were collected from a salt marsh in Faust, Utah, and are dimorphic, light brown, and 2-2.5 mm wide, or black and 1-2 mm wide. Seed germination responses of the black and brown seeds were studied over a range of salinity and temperature. Both brown and black seeds germinated at 1000 mM NaCl, and the optimal temperature for germination of both types was 20°-30°C. Variation in temperature, however, affected germination of black seeds more than brown seeds. At lower thermoperiod only 40%-50% black seeds germinated in nonsaline control, and germination was almost completely inhibited with the inclusion of salinity. However, all brown seeds germinated in control at temperatures above 5°-15°C, and inhibition caused by salinity was comparatively lower. Brown seeds had a higher germination rate than black seeds at all temperature and salinity treatments. The highest rate of germination of both seeds occurred at the temperature regime of 5°-15°C. Recovery of germination for black seeds when transferred to distilled water after being in various salinity treatments for 20 days was quite variable. Recovery decreased with increase in salinity at lower temperature regimes, increased with salinity at optimal thermoperiod, and had no effect at 20°-30°C. Brown seeds recovered poorly from salinity at all thermoperiods except 5°-15°C, where recovery decreased with an increase in salinity. Brown seeds are adapted to germination in the early part of the growing season, whereas black seeds are capable of surviving harsher conditions and can germinate in later time periods. Characteristics of the dimorphic seeds increase chances for survival in the harsh saline desert environment.     

Aquatic habitats, life history observations, and zoogeographic considerations of the spotted frog ( Rana pretiosa ) in Tule Valley, Utah

Four populations of the spotted frog, Rana pretiosa , occur in western Bonneville Basin. Only the Tule Valley populations occupy aquatic habitats associated with warm (28°C) and slightly saline (1700-2700 μmhos/cm) springs. The spotted frog in Tule Valley breeds in cold-water portions of the peripheral wetlands, which exhibit maximum temperature variations (1-25°C), maximum conductivity up to 3200 μmhos/cm, and maximum pH values up to 9.7. Adult frogs are found in habitats with temperatures of 29°C, conductivity of 4700 μmhos/cm, and pH above 9.0 in the summer. The increased summer salinity and pH in frog habitats returns to lower values by the next breeding season due to underground recharge. Breeding in Tule Valley occurs earlier than in other Bonneville locations because of the warm-water sources. Spatial and temporal distribution of the spotted frog since the regression of Lake Bonneville 15,000 years ago and threats to present habitats are discussed.     

The inland mangroves of Inagua

Summary

Mangroves located 50 km inland in the Lake Windsor basin in Inagua are described and compared with the island coastal mangroves. Measurements of soil and surface water salinity yielded high values typical of arid climates. Avicennia germinans and Laguncularia racemosa were found growing in the higher salinity soils while Rhizophora mangle was found fringing inland ocean holes with low salinities. Conocarpus erecta grew in elevated ridges. Scrub mangroves grow in the most extreme conditions of high salinity or over rocky soils. It is postulated that fresh sea water flows from ocean holes into the large Lake Windsor basin where high evaporation concentrates salts. Storms leach salts and maintain stable salinity conditions. Thus, the inland mangroves are not isolated from the sea but critically dependent on it as a source of fresh sea water. A critical examination of the data presented for the island of Barbuda by Stoddart, Bryan and Smith (1973) supports the idea that inland mangroves are connected to the sea.     

Carbon isotope discrimination and water relations of oak hybrid populations in southwestern Utah

The evergreen oak Quercus turbinella and the deciduous Q. gambelii form natural hybrids in southwestern Utah and northern Arizona. Hybrid individuals also are found in northern Utah in a region where only Q. gambelii currently exists, indicating that Q. turbinella has recently retreated southward. Our objectives were to (1) examine the ecophysiology of parental taxa and hybrids under natural conditions in southeastern Utah, and (2) investigate the level of integration between leaf carbon isotope discrimination (a synthetic gas exchange trait) and structural and chemical traits of leaves in morphologically variable hybrid populations. Leaf length, width, mass-to-area ratio (LMA, g m -2 ), and nitrogen concentration (N, g g -1 ) within 2 hybrid populations near New Harmony, Utah, were highly intercorrelated. Variation within the hybrid populations spanned mean values for these traits observed in parental taxa from adjacent ""pure"" populations of each species. Carbon isotope discrimination (Δ), an integrated measure of the ratio of intercellular to ambient CO 2 concentration, ranged from 16.1‰ to 19.6‰ within the 2 hybrid populations and was positively correlated with leaf nitrogen concentration and negatively correlated with LMA; individuals in hybrid populations with leaves resembling Q. gambelii had the highest leaf Δ and N concentrations and lowest LMA compared with leaves from plants that resembled Q. turbinella . CO 2 uptake is limited by stomatal conductance and possibly by mesophyll resistance to a greater extent in Q. turbinella phenotypes than in intermediate or Q. gambelii phenotypes. δD of stem xylem water (an indication of active rooting depth) and predawn water potential during the peak monsoon period in August were not correlated to leaf Δ values within the hybrid populations. Several individuals that were morphologically similar to Q. turbinella in the hybrid populations maintained high predawn water potentials and derived moisture from winter recharge that presumably was taken from deep soil layers. Apparently, a few adult individuals of the Q. turbinella phenotype in hybrid populations accessed water from deep in the soil profile, which enabled them to avoid summer drought. Reduced monsoonal activity may have been an important, but not the single, determinant of Q. turbinella s retreat from northern Utah during the recent Holocene.     

Effect of salinity and planting density on physiological responses of Allenrolfea occidentalis

Physiological responses of Allenrolfea occidentalis to salinity and seedling density were investigated. Effects of salinity (0, 200, 400, 600, 800, and 1000 mM NaCl) and 3 planting densities (2000, 4000, 6000 plants m -2 ) on the growth, survival, and ecophysiology of A. occidentalis , a stem succulent inland halophyte, were studied under controlled greenhouse conditions. Plants were grown in a sand culture using subirrigation. Dry mass of roots was highest at 600 mM NaCl at low density (2000 plants m -2 ), but declined as salinity increased. Tissue water content was highest at the 200 mM NaCl treatment and decreased with increased salinity. Water potential of the plants became more negative with increasing salinity due to the accumulation of NaCl in the leaves. Inorganic ions, especially Na + and Cl - , contributed substantially to dry mass. Na + and Cl - concentration in shoots and roots increased when NaCl level was increased while K + , Ca ++ , Mg ++ , SO 4 -- , and NO 3 - contents decreased. Net photosynthesis increased at low salinity (200 mM), but photosynthesis at other salinities was not significantly different from the control. While A. occidentalis is very salt tolerant and photosynthesis functioned reasonably well at high salinities, extremely high salinity did decrease dry mass of roots and shoots.     

Effect of salinity on seed germination of Triglochin maritima under various temperature regimes

Triglochin maritima L. (arrow grass), an herbaceous perennial in the family Juncaginacea, is widely distributed in inland and coastal salt marshes of North America. Triglochin maritima seeds from a population growing in a salt marsh at Faust, Utah, were germinated at 4 temperature regimes (12-h night/12-h day, 5-15° C, 10-20° C, and 15-25° C) and 5 salinities (0, 100, 200, 300, 400, and 500 mol m -3 NaCl) to determine optimal conditions for germination and level of salt tolerance. Ungerminated seeds were returned to distilled water after 20 d to determine whether seeds could recover from salinity treatments. Maximum germination occurred in distilled water, and increases in NaCl concentration progressively inhibited seed germination. No seeds germinated at concentrations higher than 400 mol m -3 NaCl. A temperature regime of low night (5° C) and high day (25° C) temperature yielded maximum germination; all other temperature regimes significantly inhibited seed germination relative to this optimum. Recovery of germination was highest at 5-25° C and lowest at 5-15° C. Recovery of seed germination when seeds were transferred to distilled water from salt solutions was highest at 5-25° C (72%) for seeds exposed to the 500 mol m -3 NaCl pretreatment and significantly reduced at other temperature regimes. The recovery germination response indicates a synergistic inhibitory interaction effect on germination when seeds were exposed to high salinities at suboptimal thermoperiods.     

Seed germination characteristics of Chrysothamnus nauseosus ssp. viridulus (Astereae, Asteraceae)

Rubber rabbitbrush ( Chrysothamnus nauseosus [Pallas] Britt. ssp. viridulus ) may prove to be a source of high-quality cis-isoprene rubber, but its establishment is limited by a lack of information on seed germination. Consequently, seeds were germinated at alternating temperatures (5–15, 5–25, 15–25, and 20–30 C) in light and dark as well as constant temperatures (15–40 C with 5-C increments) to determine temperature response. Seeds were also germinated in solutions of polyethylene glycol 6000 (0 to –5 bar), salinity regimes (1, 17, 51, and 86 mM) at all the above-mentioned temperatures to determine salinity and temperature interaction. The hormones GA 3 (0, 2.9, 29.0, and 58.0 um) and kinetin (0, 4.7, 23.5, and 47.0 um) were used to study their effect on overcoming salt- and temperature-induced germination inhibition. Seeds of C. nauseosus ssp. viridulus were very sensitive to low temperature. Best germination was achieved at 25 and 30 C, but these seeds also germinated at a higher temperature (35 C). The seeds of rabbitbrush germinated at both constant and alternating temperatures. Light appears to play little or no role in controlling germination of the seeds of rubber rabbitbrush. However, seeds of rabbitbrush were sensitive to salinity, and seed germination was progressively inhibited by increase in salt concentration, although a few seeds still germinated at the highest saline level. Progressively higher concentrations of polyethylene glycol also progressively inhibited germination. Suppression of seed germination induced by high salt concentrations and high temperatures can be partially alleviated by the application of either GA 3 or kinetin.     

The salinity during larval development affects the dispersion in adults of the tree-climbing crab Aratus pisonii

Adults of the tree-climbing crab Aratus pisonii occur in estuarine regions with a range of salinity of 0–35. However, the larvae cannot complete the development in a wide range of salinities. A study about the effect of salinity on the larval development was conducted in order to infer about adult dispersion and occurrence in a wide range of salinity. Two experiments were conducted: (1) from zoae I to megalopae stage and (2) from megalopa to juvenile stage. Larvae from eight females from Paranaguá Bay, Paraná, Brazil were obtained. After eclosion, for the first experiment, 100 zoea larvae from five females were acclimated, individualized and transferred to small aquariums with five distinct salinity treatments (S0, S5, S15, S25 and S35). For the second experiment, 50 megalopae from three females were individualized in aquariums in the same salinity treatments. Both experiments were conducted in incubator BOD with a constant temperature of 25°C and photoperiod of 12 hours (light/dark). Larvae were fed daily with eggs and naupli newly hatched of Artemia sp. The salinity affected the survival rate during the development in both experiments. Higher survival from zoea I to megalopa stage occurred in salinities 25 and 35 PSU, while from megalopa to juvenile stage in salinities 15 and 25 PSU. In both experiments the larvae did not tolerate low salinities as adults, with total mortality in S0 and S5. Our results suggest that the species have a larval export strategy of zoae larvae to oceanic regions (higher salinities) and megalopae needed to return to estuarine areas with intermediate salinities to complete the development. The occurrence of adults in estuarine areas with low (< 5 PSU) or high (> 25 PSU) salinities most likely occur after the metamorphosis to the juvenile stage by terrestrial dispersion or at the stage of megalopa (marine dispersion) during favourable weather events.     

High nitrogen availability does not improve salinity tolerance in Sarcobatus vermiculatus

Natural and anthropogenic changes in basin lake levels in the western U.S. expose saline, alkaline substrates that are commonly colonized by shrubs in the Chenopodiaceae. On a chronosequence of recently exposed substrates at Mono Lake, California, Sarcobatus vermiculatus has greatest biomass accrual, seed production, seedling establishment, and leaf N at younger sites where soils are extremely saline and alkaline. These field observations and an understanding of the role of N-containing compatible solutes in salinity tolerance of halophytes led to our prediction that Na and N interactions stimulate Sarcobatus performance. To test this, we grew Sarcobatus juveniles for 2 years in the greenhouse at 4 levels of NaCl (5, 100, 300, and 450 mM) and 3 levels of N (0.04, 0.4, and 8 mM) in a randomized, complete-block design. Contrary to our expectations, high N availability did not induce salt-stimulated growth nor did it increase salinity tolerance in Sarcobatus . Increased N nutrition also had no significant effect on leaf cation ratios or selectivity. Plants grown at high salinity had significantly lower leaf K:Na, Ca:Na, and Mg:Na ratios than plants grown at lower salinity. However, plant selectivity for the macronutrient cations remained high, even at 450 mM NaCl. Without such high selectivity, the cation nutrition of Sarcobatus would decline to even lower levels, resulting in severe nutrient deficiencies. This study suggests that the ability of Sarcobatus to attain high leaf N, rather than an interaction between Na and N, enhances its performance at saline sites. In addition, the ability of Sarcobatus to maintain high macronutrient cation selectivity despite high salinity allows its distribution to extend to extremely saline and alkaline substrates in this arid system.     

C 3 and C 4 Species Changes Identified by δ 13 C values of soil organic matter in a Colorado prairie

We measured carbon isotope signatures (δ 13 C) from 0-10 cm and 10-20 cm soil depth intervals for grassland soils near Boulder, Colorado. These grasslands included tall-, short-, and mixed-grass prairies that were grazed, ungrazed, or hayed. Soils exhibited δ 13 C signatures consistent with observations that current sites are a mix of C 3 and C 4 species, with C 3 plants more abundant in mixed-grass than in native tall- or shortgrass prairies. The δ 13 C signatures were not significantly different for grassland types; however, management treatments (grazing, no grazing, haying) significantly influenced changes in soil δ 13 C signatures from the 0-10 cm to 10-20 cm soil depth intervals. We observed a correlation ( r = 0.63) between isotopic values of surface soils and percent native species in total vegetation cover. Overall, the community type with the lowest percentage of nonindigenous species cover had the most enriched δ 13 C signature. Sites currently grazed by prairie dogs, cattle, or both herbivores had stronger C 3 signatures, indicating that grazing may have increased C 3 plant productivity in these communities at the expense of C 4 grasses. This finding differs from studies of native shortgrass steppe where grazing has the opposite effect on the relative abundance of these 2 functional groups of plants. This result, along with the correlation between C 3 isotopic values and nonnative vegetation abundance, provides evidence that management practices that maintain dominance of C 4 grasses should be encouraged.     

Planktonic copepod community of a reef zone in the southern Gulf of Mexico

ABSTRACT

In this study, the variation of seasonal and inter-annual density and diversity of the copepod community in the Parque Nacional Sistema Arrecifal Veracruzano (PNSAV) was analysed. Samples were collected under nortes, rainy and dry weather conditions in 2011, as well as under nortes and dry weather conditions in 2012 and 2013 in four transects. Surface trawls with 330-μm conical nets were made. The temperature, salinity and dissolved oxygen were measured in situ. The values obtained were 23.07 ± 0.53 to 29.29 ± 0.27°C for temperature, 33.43 ± 0.49 to 35.91 ± 0.09 for salinity, and 2.52 ± 0.08 to 6.56 ± 0.08 mg l^?1 for dissolved oxygen. The copepods collected belonged to 19 families, 28 genera and 62 species. Copepods represented between 69.74% and 76.79% of the abundance of crustaceans present in zooplankton. The highest number of copepods occurred under nortes weather conditions in 2011 with 401,885 ± 28,092 copepods/100 m³ of the species Temora stylifera. In 2012, 256,325 ± 76,872 copepods/100 m³ of the species Paracalanus aculeatus were obtained and in 2013, 311,526 ± 76,872 copepods/100 m³ of the species T. turbinata. The highest specific richness was found in the southern zone with 28 species. In 2013 the highest density was found in the northern zone with 100,323 ± 28,888 copepods/100 m³. The highest diversity was found under dry weather conditions in 2011 with 3.71 bits/individual. In the 3 years of study, 24 species were dominant; 12 of these, appeared in the 3 years of sampling: T. stylifera, T. turbinata, Labidocera scotti, P. aculeatus, O. latus, Pontellopsis villosa, Centropages velificatus, Parvocalanus crassirostris, Corycaeus speciosus, Undinula vulgaris, Oithona plumifera, and Farranula gracilis. Canonical correlation analysis showed the formation of five groups explained by the neritic or oceanic affinity of the species and their tolerance to changes in salinity or temperature.     

Relating abundance of purpleback flying squid Sthenoteuthis oualaniensis (Cephalopoda: Ommastrephidae) to environmental parameters using GIS and GAM in south-eastern Arabian Sea

The distribution pattern of purpleback flying squid and the relationship between its abundance and environmental variables in the south-eastern Arabian Sea were analysed using a geographical information system (GIS) and a generalised additive model (GAM). Highest abundances were observed during December and January within 10 and 13°N and 71 and 72°E around the Lakshadweep Islands. The mean abundance in the area was 4.21 tonnes/km² and the maximum sustainable yield (MSY) was estimated as 0.63 million tonnes. GAM indicated that very high squid abundance was associated with low values of dissolved oxygen (6.01–6.27 mg/L), sea surface temperature (28.03–28.62°C), pH (7.75–8.56), salinity (30.42–34.48 psu), chlorophyll-a (0.4–0.6 mg/m³), zooplankton biomass (0.23–0.64 mL/m³), and shallow 20°C isotherm (101.2–134.7 m) and mixed layer depth (17.8–29.8 m). As a carnivore from paralarval stages, S. oualaniensis depends on secondary and tertiary production to sustain its population for which primary production is used up. In the tropical Arabian Sea where temperature differences are not so pronounced, S. oualaniensis distribution was found to be related to a low but very narrow sea surface temperature (SST) band. There is sufficient fishable biomass in the area to possibly launch a new targeted oceanic squid fishery from the western seaboard of India.     

Relationships between insolation and rattlesnake hibernacula

We examined the relationship between insolation, climate, and hibernacula of black-tailed ( Crotalus molossus ), Great Basin ( Crotalus lutosus ), and western diamondback ( Crotalus atrox ) rattlesnakes at 4 sites in Arizona, Nevada, and Utah. Hibernacula were located through a combination of visual searches and radio telemetry from 1995 to 2003. We used global information systems to calculate insolation and compared hibernaculum insolation values with random points representing available insolation of the surrounding habitat. Insolation reflects soil temperatures, and we predicted that hibernacula in cool climates, at high elevations, and at high latitudes would have higher insolation relative to their surroundings, while hibernacula in warmer climates would not differ from their surroundings in insolation. Coolest temperatures, highest elevations, and highest latitudes occurred on the C. lutosus and C. molossus sites, where hibernaculum insolation was higher than surrounding insolation. Temperatures were intermediate on the high-elevation C. atrox site, where hibernaculum insolation did not differ from random-point insolation. Temperatures were highest on the low-elevation C. atrox site, where hibernaculum insolation was unexpectedly lower than random-point insolation. Our observations suggest that rattlesnakes in cool climates utilize hibernacula with insolation values higher than those of their surroundings. Rattlesnakes in warm climates utilize hibernacula with insolation values lower than or similar to those of their surroundings.     

Microhabitat selection by the johnny darter, Etheostoma nigrum Rafinesque, in a Wyoming stream

Microhabitat selection by the johnny darter ( Etheostoma nigrum ) was examined in the North Laramie River, Platte County, Wyoming, where it does not occur with other darter species in the same stream reach. Electivity indices based on microhabitat observations indicate that E. nigrum avoids riffles and selects certain microhabitats characterized by intermediate water depths in pools and slow-moving runs with a substrate composed primarily of silt and sand. Niche breadth and electivity values for total depth, bottom water velocity, and substrate measurements from this study indicate that E. nigrum is a habitat generalist, except at the extreme ends of the habitat gradient. Habitat use here is generally similar to other studies where E. nigrum occurred with one or more other darter species. This study found little evidence for competitive release in the absence of other darters.     

Response of tree ring holocellulose δ 13 C to moisutre availability in Populus fremontii at perennial and intermittent stream reaches

We measured δ 13 C of tree ring holocellulose to assess intra- and interannual variation in integrated leaf gas exchange responses of Frémont cottonwood ( Populus fremontii ) to monsoonal moisture inputs in southeastern Arizona. We predicted that δ 13 C of trees growing along drought-susceptible intermittent reaches of this semiarid river system would be more responsive to monsoonal moisture inputs than trees found along perennial reaches, where groundwater is consistently available. We sampled stem xylem cores from 7 trees, each at an intermittent and perennial reach of the San Pedro River near Tombstone, Arizona. We identified and subdivided individual rings from 1990 to 2000. δ 13 C of holocellulose from these subdivisions was compared with precipitation amount, atmospheric vapor pressure deficit ( D a ), and 90% exceedence flows ( Q 90 ) calculated from seasonal flow duration data. δ 13 C values were higher at the intermittent reach than at the perennial reach. Furthermore, annual ring δ 13 C values at the perennial reach were not correlated with stream flow, precipitation, or D a . δ 13 C values for trees at the intermittent reach were negatively correlated with monsoon stream flow, precipitation, or D a . δ 13 C values for trees at the intermittent reach were negatively correlated with monsoon season (1 July-15 September) Q 90 ( r 2 = 0.50, P = 0.015) and positively correlated with D a ( r 2 = 0.45, P = 0.03). Shifts in δ 13 C between the inner- and outer-third of the annual ring were used as a measure of intra-annual variation. These shifts were correlated with monsoon season D a ( r 2 = 0.57, P = 0.01) and Q 90 ( r 2 = 0.59, P = 0.005) for trees growing along the intermittent reach. Intra- and interannual variation in integrated photosynthetic response exists at the population-scale for these native, riparian forests. Changes in monsoonal precipitation and stream flow may differentially alter photosynthetic gas exchange of P. fremontii and function of these riparian ecosystems.     

Tropical cyclones and reproductive ecology of Crocodylus acutus Cuvier, 1807 (Reptilia: Crocodilia: Crocodylidae) on a Caribbean atoll in Mexico

Crocodylus acutus, a coastal species nesting in sand beaches, could be affected by increasing tropical cyclone frequency. We studied key characteristics of C. acutus reproductive ecology on Banco Chinchorro atoll from 2006 to 2009, including the impact of two tropical cyclones. Hurricanes increased canopy openness causing earlier nesting the following year. Crocodiles nested at the beginning of the wet season with hatching in mid-wet season; this could represent a compromise between risking nest flooding and increasing freshwater availability for hatchlings. Tropical cyclones dramatically reduced nesting success by cooling and flooding clutches. Nursery sites were usually hypersaline, but heavy rainfall from tropical cyclones can likely benefit hatchling survival by decreasing salinity. While tropical cyclones have negative short-term impacts on crocodile nesting, they likely have an overall beneficial effect by creating and maintaining open sandy nesting areas used by C. acutus and they may explain its widespread distribution in Caribbean coastal areas.     

The complete larval development of the Mangrove Ocypodid crab Macrophthalmus depressus Ruppell, 1830 (Brachyura: Macrophthalminae) reared in the laboratory

Macrophthalmus depressus larvae were reared in the laboratory using filtered estuarine water of salinity 25±1 ppt and temperature 29–31°C. M. depressus reaches the first crab stage after passing through five zoeal and a megalopa stage requiring 22–23 days. Each stage is described in detail and compared with other known species of the genus.     

Improving seed germination of Salicornia rubra (Chenopodiaceae) under saline conditions using germination-regulating chemicals

Salicornia rubra Nels. (Chenopodiaceae) is a salt-tolerant annual species occurring in salt playas of the Great Basin desert in western United States. It forms pioneer communities on the most saline location of an inland salt playa at Goshen, Utah. Seeds of Salicornia rubra are capable of germinating at 1000 mM NaCl at 25-35° C alternating temperature regime. Dormancy-regulating chemicals were evaluated for their ability to alleviate the innate and salinityenforced dormancy in seeds of Salicornia rubra . Betaine, GA3, kinetin, fusicoccin, ethephon, thiourea, proline, and nitrate had no effect in alleviating primary dormancy. Increases in NaCl concentration progressively inhibited germination of Salicornia rubra seeds. Ethephon, fusicoccin, GA3, kinetin, thiourea, and nitrate promoted germination under low saline conditions. At high salinity fusicoccin had no effect, whereas GA3, kinetin, and ethephon substantially alleviated salinity effects. Application of these dormancy-regulating compounds could be of practical value in seeding a saline area for restoration purposes, particularly under high saline conditions.     

Zoeal development of Ethusa microphthalma smith, 1881 (Brachyura,Dorippidae) reared in the laboratory,with a comparison of other dorippid zoeae

The complete zoeal development of a dorippid crab in the subfamily Ethusinae is described for the first time from a known parental female. The ovigerous Ethusa microphthalma was collected in the northern Gulf of Mexico off Louisiana. Larvae passed through four zoeal stages, and the megalopa was reached in 59 days at 20°C and 35 ppt salinity. The larvae differ from those of the few other dorippids for which a zoea is known. Salient distinguishing features include long lateral carapace spines, the presence of six setae on the endopod of the maxillule and maxilla, and a spinose antennal exopod lacking projecting mid-length spines or setae. Zoeal characters are compared to those known for the allied subfamily Dorippinae, and all references to zoeae of the Dorippidae are tabulated.