scholarly journals Effects of Different Salinities on Juvenile Growth ofGammarus aequicauda(Malacostraca: Amphipoda)

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Lídia Delgado ◽  
Guillermo Guerao ◽  
Carles Ribera

Gammarus aequicaudais a euryhaline amphipod that is a common inhabitant of brackish environments of the Mediterranean Sea. In the Ebro delta, the population density ofG. aequicaudais highly variable throughout the year. The main objective of this study is to investigate the effect of salinity on the growth ofG. aequicaudajuveniles.G. aequicaudaembryos and juveniles can survive and grow in the laboratory between 2 psu and 40 psu salinity, depending on the previous acclimation period for the reproductive individuals. Adults acclimated at 34 psu produced embryos and juveniles that survived and developed at salinities between 9 psu and 40 psu; adults acclimated at 9 psu produced embryos and juveniles that could develop in oligohaline conditions. The lower growth rate values were 10.9 μm d−1and 13.5 μm d−1at 40 psu and 2 psu, respectively, with the higher values of 18.0 μm d−1and 18.5 μm d−1at 19 and 34 psu, respectively.


2004 ◽  
Vol 313 (1) ◽  
pp. 63-73 ◽  
Author(s):  
O. Chomsky ◽  
Y. Kamenir ◽  
M. Hyams ◽  
Z. Dubinsky ◽  
N.E. Chadwick-Furman


2007 ◽  
Vol 152 (2) ◽  
pp. 351-361 ◽  
Author(s):  
Stefano Goffredo ◽  
Erik Caroselli ◽  
Elettra Pignotti ◽  
Guido Mattioli ◽  
Francesco Zaccanti


2002 ◽  
Vol 74 (1) ◽  
pp. 135-144 ◽  
Author(s):  
A. Belenguer ◽  
J. Balcells ◽  
M. Fondevila ◽  
C. Torre

AbstractThe present study compares estimates of caecotrophes production from urinary purine derivatives (PD) excretion with that from preventing caecotrophy by using a neck collar. A total of 64 New Zealand growing male rabbits were used to study the effect of diet composition on caecotrophes production. Diets were formulated using two sources of structural carbohydrates (fibre): alfalfa hay (AH) and sugar-beet pulp (SBP), mixed at two constant proportions, (0·75: 0·25) AH diets and (0·25: 0·75) SBP diets. Both diets included either barley or maize grain at two fibre: grain ratios (F/G, 80: 20 and 45: 55). Diets were given ad libitum. Growth rate, dry matter intake and digestibility were not modified by the grain source, although high F/G diets resulted in a lower growth rate (19·8 v. 26·4 g/day; P < 0·001). Between fibre sources, dry-matter intake and growth were higher in AH than in SBP diets (122·5 and 25·6 v. 101·6 and 20·4 g/day, respectively, P < 0·001 and P < 0·01). Rabbits given high F/G ratio and AH diets excreted more caecotrophes than those given low F/G ratio and SBP diets (19·5 and 20·9 v. 16·3 and 14·85 g/day, respectively). Microbial-N recycling through the caecotrophy process was higher when considering data from PD excretion (1·33 g/d) than when estimated by preventing caecotrophy (0·72 g/day).



2016 ◽  
Vol 30 (06) ◽  
pp. 1650059
Author(s):  
Jingjing Gao ◽  
Mingwen Chen ◽  
Zidong Wang

The convection of ambient flow field has a significant influence on the pattern formation of growing particles. In this paper, we investigate the shape evolution of particles growing in supersaturated solution affected by straining flows. By using the multiple variable asymptotic expansion method, we obtain the asymptotic solution. The solution indicates that the interface microstructure is greatly affected by the straining flows. The flow results in a higher growth rate in the surface where it is incoming and a lower growth rate where it is outgoing. Besides, the flow also has effects on the concentration distribution.



Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2196 ◽  
Author(s):  
Vinet ◽  
Bigot ◽  
Petrucci ◽  
Papagiannaki ◽  
Llasat ◽  
...  

Recent events in Western Attica in Greece (24 deaths in November 2017), in the Balearic Islands (13 deaths in October 2018), and in southern France (15 deaths in October 2018) show that flood-related mortality remains a major concern in Mediterranean countries facing flash floods. Over the past several years, many initiatives have arisen to create databases on flood-related mortality. An international initiative started in 2011 pooling regional and national databases on flood mortality from region and/or countries bordering the Mediterranean Sea. The MEditerranean Flood Fatality Database (MEFF DB) brings together, in 2018, six Mediterranean regions/countries: Catalonia (Spain), Balearic Islands (Spain), Southern France, Calabria (Italy), Greece, and Turkey, and covers the period 1980–2018. MEFF DB is on progress and, every year, new data are included, but for this study, we kept only the preliminary data that were geolocated and validated on 31st of December 2018. This research introduces a new step in the analysis of flood-related mortality and follows the statistical description of the MEFF DB already published. The goals of this paper are to draw the spatial distribution of flood mortality through a geographical information system (GIS) at different spatial scales: country, NUTS 3 (Nomenclature of Territorial Units for Statistics. Level 3) regions, catchment areas, and grid. A fatality rate (F: number of deaths/year/million of inhabitants) is created to help this analysis. Then, we try to relate mortality to basic (human or physical) drivers such as population density, rainfall seasonality, or rainfall frequency across the Mediterranean Basin. The mapping of F shows a negative mortality gradient between the western and the eastern parts of the Mediterranean Sea. The south of France appears to be the most affected region. The maps also highlight the seasonality of flood-related deaths with the same west–east gradient. It confirms that flood mortality follows the climatological seasonal patterns across the Mediterranean Basin. Flood-related fatalities mainly occur during the early fall season in the western part of the Mediterranean area, while the Easter Basin is affected later, in November or during the winter season. Eastern Turkey introduces another pattern, as mortality is more severe in summer. Mortality maps are then compared with factors that potentially contribute to the occurrence of flood fatalities, such as precipitation intensity (rainfall hazard), to explain geographical differences in the fatality rate. The density of a fatal event is correlated to the population density and the rainfall frequency. Conversely, the average number of deaths per event depends on other factors such as prevention or crisis management.



Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 438-444 ◽  
Author(s):  
William H. Ahrens ◽  
E. W. Stoller

Triazine-susceptible (S) and -resistant (R) biotypes of smooth pigweed (Amaranthus hybridusL.) were grown in the field under competitive conditions at varying initial proportions of S and R plants. R plants were less competitive than S plants as measured by accumulation of total above-ground dry weight and seed dry weight. S and R plants were also grown in the field under non-competitive conditions at 100, 40, and 10% light. Growth rate at 10% light did not differ between S and R plants. At the two higher light intensities, dry-matter accumulation 11 weeks after seeding was about 40% less in the R plants. At 100% light, relative growth rate and net assimilation rate were lower in the R plants by about 3.5 and 19%, respectively. The light- and CO2-saturated rates of CO2fixation in intact leaves of glasshouse-grown R plants were 20% less than those in S plants. An apparent 10 and 20% greater number of chlorophyll molecules per photosystem II reaction center in R plants (as compared with S plants) grown in the field at 40 and 100% light, respectively, did not explain differences between the S and R biotypes in photo synthetic capacity. The S and R plants did not differ in specific leaf weight or chlorophyll content on a leaf-area basis. Lower growth rate of R plants may be responsible for inferior competitive ability of R biotypes and could be the result of an impaired photosynthetic capacity.



2013 ◽  
Vol 79 (13) ◽  
pp. 4145-4148 ◽  
Author(s):  
Takanori Awata ◽  
Mamoru Oshiki ◽  
Tomonori Kindaichi ◽  
Noriatsu Ozaki ◽  
Akiyoshi Ohashi ◽  
...  

ABSTRACTThe phylogenetic affiliation and physiological characteristics (e.g.,Ksand maximum specific growth rate [μmax]) of an anaerobic ammonium oxidation (anammox) bacterium, “CandidatusScalindua sp.,” enriched from the marine sediment of Hiroshima Bay, Japan, were investigated. “CandidatusScalindua sp.” exhibits higher affinity for nitrite and a lower growth rate and yield than the known anammox species.



2006 ◽  
Vol 73 (2) ◽  
pp. 432-441 ◽  
Author(s):  
Olle Rengby ◽  
Elias S. J. Arnér

ABSTRACT Release factor 2 (RF2), encoded by the prfB gene in Escherichia coli, catalyzes translational termination at UGA and UAA codons. Termination at UGA competes with selenocysteine (Sec) incorporation at Sec-dedicated UGA codons, and RF2 thereby counteracts expression of selenoproteins. prfB is an essential gene in E. coli and can therefore not be removed in order to increase yield of recombinant selenoproteins. We therefore constructed an E. coli strain with the endogenous chromosomal promoter of prfB replaced with the titratable PBAD promoter. Knockdown of prfB expression gave a bacteriostatic effect, while two- to sevenfold overexpression of RF2 resulted in a slightly lowered growth rate in late exponential phase. In a turbidostatic fermentor system the simultaneous impact of prfB knockdown on growth and recombinant selenoprotein expression was subsequently studied, using production of mammalian thioredoxin reductase as model system. This showed that lowering the levels of RF2 correlated directly with increasing Sec incorporation specificity, while also affecting total selenoprotein yield concomitant with a lower growth rate. This study thus demonstrates that expression of prfB can be titrated through targeted exchange of the native promoter with a PBAD-promoter and that knockdown of RF2 can result in almost full efficiency of Sec incorporation at the cost of lower total selenoprotein yield.



2011 ◽  
Vol 183 (9) ◽  
pp. E527-E528
Author(s):  
R. Collier


2016 ◽  
Author(s):  
Matteo Nannini ◽  
Maurizio Florio ◽  
Maria Chiara Manauzzi ◽  
Agnese Marchini ◽  
Giancarlo Raiteri ◽  
...  

The concentration of Green House Gasses and specifically the concentration of CO2 in the atmosphere is continuously increasing since the industrial revolution and it is the most relevant anthropic cause driving climate changes. Two of the strongest symptoms of those changes are the Global Warming and the Ocean Acidification which are progressively altering marine ecosystems and the populations of living organisms they support. The Mediterranean Sea is widely considered a 'laboratory basin' by suffering dramatic changes in its oceanographic and biogeochemical conditions derived from natural and anthropogenic forces. Calcifying seaweeds are the most important 'bioconstructors', from mesolittoral to circalittoral fringe, providing habitats and ecological niches for other species (i.e. biodiversity promoters) but also are good 'recorders' of the environmental condition they experience (i.e. biondicators). In this study we focused on the reef-forming Ellisolandia elongata from the Gulf of La Spezia (N-W Mediterranean Sea) by comparing the physical properties, growth rate and abundance of associated fauna in natural and experimental conditions (temperature and pH expected for 2050-2100). Four sampling sites were chosen in the intertidal zone. Reef samples were bring in the laboratory and put in experimental conditions for a month. Four aquaria simulated the actual conditions of temperature and pH, other 4 aquaria simulated temperature (+3°C) and pH (7.7) expected for the year near future. E. elongata grown in the natural and experimental conditions withstand mechanical stress in slightly different ways. The study of the effect of temperature and pH variations on growth rate and associated fauna of E. elongata reef is still in progress.



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