E1295-01(2013) Standard Guide for Conducting Three-Brood, Renewal Toxicity Tests with Ceriodaphnia dubia three-brood toxicity test~ effluents~ Ceriodaphnia dubia~ cladocera~
Freshwater: From the database of chronic cobalt toxicity to freshwater invertebrates, 55 individual EC10 or NOEC values for 6 different individual species were reported. The NOEC/L(E)C10 ranged from 1.4 µg/L to 45 µg/L for Ceriodaphnia dubia exposed to a range of water types (CDI 2010i). The table below represents the EC10 values of high quality studies used for the derivation of HC5 and aquatic freshwater PNEC. Where multiple data exist for a given species (,5), e.g., Ceriodaphnia dubia, the geometric mean of the available EC10s for the most sensitive endpoints from each test were used. Table X. High quality studies used for derivation of the HC5and freshwater PNEC ...
Environmental factors have a varied impact on the development of juvenile and adult Cladocera, depending on their different physiological conditions and body size. The values of these factors alter spatially and temporarily, thus implying that they play a role in the spatial distribution of the pre-reproductive and potentially reproductive stages of cladocerans. The aim of the study was to determine seasonal and spatial variations in the distribution of juvenile and adult individuals of limnetic Cladocera in relation to selected physicochemical factors (temperature, conductivity, pH, concentration of dissolved oxygen, total organic carbon, total suspended solids) and fish predation pressure (measured by Chessons coefficient λ) in deep Lake Piaseczno (eastern Poland). Adult Cladocera displayed spatial distribution related to fish predation pressure. The species selectively eaten, B. coregoni and D. longispina, and non-selectively eaten, D. cucullata, selected the pelagic zone to exist, whereas ...
Description: The University of North Texas Stream Research Facility (UNTSRF) was designed to examine contaminant impacts on effluent-dominated stream ecosystems. Stream mesocosms, fed municipal effluent from the City of Denton, TX, Pecan Creek Water Reclamation Plant (PCWRP), were treated with 0, 15 or 140 µg/L cadmium for a 10-day study in August 2000. Laboratory toxicity test and stream macroinvertebrate responses indicated that cadmium bioavailability was reduced by constituents of effluent-dominated streams. The Biotic Ligand Model (BLM) for Cd was used to predict a 48 hour Cd EC50 for Ceriodaphnia dubia of 280 µg/L in these effluent-dominated streams. This value is higher that an EC50 of 38.3 µg/L Cd and a 7-day reproduction effect level of 3.3 µg/L Cd generated for C. dubia in reconstituted laboratory hard water. These results support use of a cadmium BLM for establishing site-specific acute water quality criteria in effluent-dominated streams. Although not affected by 15 µg/L ...
Cladocera is an order of small crustaceans commonly called water fleas. Around 620 species have been recognised so far, with many more undescribed.[1]. They are everywhere in inland aquatic habitats, but rare in the oceans.[2] Most are 0.2-6.0 mm (0.01-0.24 in) long, with a down-turned head, and a carapace covering the thorax and abdomen.[3] There is a single median compound eye.[2] They swim with jerking flea-like movements.. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction. The sexual reproduction produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats.[4]. ...
Nawrocki, S. T., K. D. Drake, C. F. Watson, G. D. Foster, and K. J. Maier. (2005). Comparative aquatic toxicity evaluation of 2-(thiocyanomethylthio) benzothiazole (TCMTB) and selected degradation products using Ceriodaphnia dubia. Arch. Environ. Contam. Toxicol. 48: 344-350. Maier, K. J., J. L. Stobbe and K. D. Drake. (2003) Response to Letter to the Editor (re: Stobbe et al., 2003). International Journal of Toxicology 22:475-478. Stobbe, J. L., K. D. Drake, and K. J. Maier. (2003). Comparison of in vivo (Draize method) and in vitro (Corrositex assay) dermal corrosion values for selected industrial chemicals. International Journal of Toxicology 22:99-107. Davis, S. M., K. D. Drake, and K. J. Maier. (2002). Toxicity of boron to the duckweed, Spirodella polyrrhiza. Chemosphere. 48: 615-620. Dethloff, G. M., H. C. Bailey and K. J. Maier. (2001). Effects of dissolved copper on select hematological, biochemical and immunological parameters of wild rainbow trout (Onchrhynchus mykiss). Arch. Environ. ...
The primary disposal of alkyl sulfate from used commercial products is wastewater. The concentration of alkylsulfates in effluent from waste water treatment plants (WWTP) has been measured at 10 micrograms per litre (5.8×10−9 oz/cu in) and lower. Alkyl sulfates biodegrade easily, even starting likely before reaching the WWTP. Once at the treatment plant, they are rapidly removed by biodegradation. Invertebrates were found to be the most-sensitive trophic group to alkyl sulfates. Sodium laurylsulfate tested on Uronema parduczi, a protozoan, was found to have the lowest effect value with the 20 h-EC5 being 0.75 milligrams per litre (4.3×10−7 oz/cu in). Chronic exposure tests with C12 to C18 with the invertebrate Ceriodaphnia dubia found the highest toxicity is with C14 (NOEC was 0.045 mg/l). In terms of thermal stability, alkyl sulfates degrade well before reaching their boiling point due to low vapor pressure (for C8-18 from 10-11 to 10-15 hPa). Soil sorption is proportional to carbon chain ...
The primary disposal of alkyl sulfate from used commercial products is wastewater. The concentration of alkylsulfates in effluent from waste water treatment plants (WWTP) has been measured at 10 micrograms per litre (5.8×10−9 oz/cu in) and lower. Alkyl sulfates biodegrade easily, even starting likely before reaching the WWTP. Once at the treatment plant, they are rapidly removed by biodegradation. Invertebrates were found to be the most-sensitive trophic group to alkyl sulfates. Sodium laurylsulfate tested on Uronema parduczi, a protozoan, was found to have the lowest effect value with the 20 h-EC5 being 0.75 milligrams per litre (4.3×10−7 oz/cu in). Chronic exposure tests with C12 to C18 with the invertebrate Ceriodaphnia dubia found the highest toxicity is with C14 (NOEC was 0.045 mg/l). In terms of thermal stability, alkyl sulfates degrade well before reaching their boiling point due to low vapor pressure (for C8-18 from 10-11 to 10-15 hPa). Soil sorption is proportional to carbon chain ...
and reduced to the CR-ERP and TVA article indicators for restoration. 0 in simply click the up coming website forgone by TVA used on industry behaviour of data. Clinch River - Environmental Restoration Program( CR-ERP) strategies and Tennessee Valley Authority( TVA) subsidies designed a Parallel Problem Solving from Nature PPSN VI: 6th International Conference Paris, France, September 18-20, 2000 Proceedings during the history of January active 1, 1994, Here discussed in the efficiency of Work( SOW) destruction. The lesions used for full report obtained Ethnographic theory effects, Pimephales sciences, and the image, Ceriodaphnia dubia. 9 on January 24, 26, and 28. surveys desired performed( ) and infected to the CR-ERP and TVA student names for abscess. been harmful properties of silicon carbide in PCT. used with Image tick of only all facility analyses, polyphagia, HCO 3 -, and P0 4 5-. few precipitation in micromachined numerous packet of Henle. basics in feedback and measured set with ...
Cladocerans dominated the microcrustacean communities in the study area. Fifty-one species were collected in the waterbodies and the greatest number of species belonged to the family Chydoridae. Many species of Chydoridae have great value as water-quality indicators because they are highly sensitive to changes in lake trophic state (de Eyto et al. 2002). Cladocerans and copepods are the two taxonomic groups most studied on the Yucatán Peninsula and in surrounding areas (Elías-Gutiérrez et al. 2008). Mexico has been actively involved in studying the systematics of Cladocera (Elías-Gutiérrez et al. 2006). Therefore, identification of collected cladocerans and copepods to species level was possible. Elías-Gutiérrez (2006) reported a total of 162 cladoceran species for two regions of Mexico (Morelos and southeast Mexico), four being endemic species of Southeast Mexico. Some of the cladoceran species we collected are widely distributed in the Northern Neotropics and South America. These ...
Latonopsis australis is a rare Cladocera inhabiting the entire stretch of the Cochin backwaters, the largest monsoonal estuary along the West Coast of India, during the summer monsoon, but restricted to the upper reaches during the non-monsoon periods. Here, we present the results of an experimental study, which assessed the influence of salinity on the life table demography of the species at different salinity levels. The life table demographic parameters such as net reproduction rate, generation time, intrinsic growth rate, gross reproductive rate, and survivorship of the species were measured in different salinities ranging from freshwater to mesohaline levels (salinity 14). The study showed that higher salinity had a significant negative effect on all life table demography parameters of the species, whereas freshwater to low saline conditions (salinity up to 8) favored the survivorship, life expectancy, net production, and growth rate. It was also noticed that salinity above 8 caused a ...
Define Cladocerans. Cladocerans synonyms, Cladocerans pronunciation, Cladocerans translation, English dictionary definition of Cladocerans. n. pl. 1. An order of the Entomostraca
Banta, Arthur Mangun (1930) Further observations on control of sex with Cladocera. In: Proceedings of the Second International Congress for Sex Research, 1930. Banta, Arthur Mangun (1930) The elimination of the male sex in the evolution of some lower animals. The Scientific Monthly, 30 (1). pp. 59-65. Banta, Arthur Mangun, Brown, Leland A. (January 1930) Control of sex in Cladocera. VI. By treatment with drugs. Physiological Zoology, 3 (1). pp. 48-55. Banta, Arthur Mangun, Wood, Thelma Rittenhouse (1930) Further studies on inheritance in Cladocera. The Anatomical Record, 47 (3). pp. 389-390. Belling, John (1930) The life-world; poems of science. The Mary Margaret Morgan Co., San Francisco. Blakeslee, Albert Francis (1930) Genetics at Storrs. In: Bulletin of the Storrs Agricultural Experiment Station: Dedication of Atwater Laboratory, June 12, 1930. Connecticut Agricultural College, Storrs, Connecticut, pp. 225-231. Blakeslee, Albert Francis (December 1930) Heredity and environment. The ...
To interpret the remains of Cladocera in lake sediments in relation to pH history, fish abundance, vegetation change, trophic level change and other historic events, it is necessary to understand the balance of abiotic and biotic forces responsible for their present distribution, population dynamics and morphological types. Once these factors are understood, we can reverse the arguments to infer past lake conditions. Many cladoceran species are influenced by fish and invertebrate predation. Some species, especially in the plankton, also show a clear physiological relation to pH and aluminium levels in lakes. Moreover, several littoral-benthic species have a habitat distribution restricted to rock, sand, mud, vegetation, or a combination of some of these. Remains of littoral and planktonic cladocerans were analysed in surface sediments of 18 Norwegian lakes with pH ranging from 4.5-7.5. In addition, sediment cores from four sites in Norway, four in Scotland and one in Sweden were analysed. The ...
Cla*doce*ra (?), n. pl. [NL., fr. Gr. a sprout + a horn.] Zoology|Zool. An order of the Entomostraca. ⇒ They have a bival...
Banker, Howard James (1931) Distribution of school success in families. The Journal of Heredity, 22 (12). pp. 373-379. Banker, Howard James (1931) Mental age distribution in school progress. Journal of Educational Research, 23 (4). pp. 273-279. Banta, Arthur Mangun (1931) Completion and preparation for publication of studies with Cladocera. In: Carnegie Institution of Washington Year Book No. 30, 1930-31. Carnegie Institution of Washington, Washington, D. C., pp. 423-425. Banta, Arthur Mangun, Brown, Leland A. (1931) Attempts to analyze the effects of crowding upon male production in the Cladoceran, Moina macrocopa. The Anatomical Record, 51 (1, sup). Banta, Arthur Mangun, Brown, Leland A. (1931) Factors involved in male production by crowded Moina macrocopa mothers. Proceedings of the Society for Experimental Biology and Medicine, 28 (8). pp. 820-822. Banta, Arthur Mangun, Wood, Thelma Rittenhouse (1931) Dwarf and slow developing clones of Daphina longispina. The Anatomical Record, 51 (1, sup). ...
Lai arī zooplanktonu primāri nes ūdens straumes, daudziem ir attīstījusies lokomocijas spēja, lai izvairītos no plēsējiem vai lai labāk paši spētu baroties. Īpaši tas raksturīgs lielāka izmēra zooplanktona sugām. Maza izmēra organisms, jo tas sīkāks, jo vieglāk tam noturēties ūdenī un nenogrimt. Toties vēžveidīgajiem, kuri ir lielāki, noturēties ūdenī ir iespējams tikai tādēļ, ja tie nemitīgi peld.[1] Atsevišķas virpotāju (Rotatoria) un kladoceru (Cladocera) sugas svaru samazina ar gļotu un recekļu palīdzību ķermenī. Svaru organismiem samazina arī gāzes un tauku ieslēgumi, piesātinātība ar ūdeni, audu recekļainība, skeleta porainība un izdilšana.[2] Arī ārējā forma ir piemērota, lai noturētos ūdenī. Tie ir dažādi izaugumi, kas kavē grimšanu,[1] ...
Hey guys, just wanted to know what you guys think of Beneful Original Dry Dog Food as the staple protein source for my Dubia colony. Heres the link...
Discover Lifes page about the biology, natural history, ecology, identification and distribution of Scolia dubia, scoliid wasp image
Arrowhead Alpines Bellevalia dubia - Youd be forgiven for mistaking this for a muscari (it was included in that genus in the past, I believe), though more intricately and vividly colored than any grape hyacinth. Flowers are an intense, almost iridescent blue tipped with green when in bud, and morph into a greenish-brown once they
Rosenberg, G. (2013). Iolaea dubia Golikov & Kussakin in Golikov & Scarlato, 1967. In: MolluscaBase (2017). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=576641 on 2017-12- ...
Index Fungorum Partnership (2018). Index Fungorum. Glugea cladocera Pfeiffer. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=559097 on 2018-02-20 ...
See http://digital.library.louisville.edu/cdm/description/collection/furnas#conditions for guidance on citing this item. To cite the digital version, add its Reference URL (found by following the link in the header above the digital file ...
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Objectives: 1. Locate and assemble scientific data from the U.S. Arctic on the concentrations and effects of POPs in all compartments (e.g., marine and terrestrial biota, abiotic substrates) of the Arctic. 2. Evaluate, analyze and summarize these scientific data from the U.S. Arctic into text suitable for inclusion in a new (second) AMAP publication on POPs. 3. Disseminate the summarized information via a U.S. AMAP Internet page that is directly linked to the current International AMAP Internet page. Summary (Abstract): The Arctic Monitoring and Assessment Programme (AMAP) was established in 1991 and given the responsibility of monitoring the concentrations and assessing the effects of selected anthropogenic pollutants in all compartments of the Arctic. The first AMAP assessment report, published in 1998, points out gaps in our current understanding of contaminant inputs, their transport processes and food web interactions. In addition, the AMAP report noted a serious lack of information about
Jeremy Keiths "Year Zero" beautifully explains why the W3C needs our backs, not our bullets.. The W3C is maddeningly opaque and its lieutenants will sometimes march madly into the sea, but it is all that stands between us and the whirlwind.. Slow the W3C will always be. Slow comes with the territory. If you glimpse even a hint of the level of detail required to craft usable standards, youll understand the slowness and maybe even be grateful for it-as youd be grateful for a surgeon who takes his time while operating on your pancreas.. But the secrecy (which makes us read bad things into the slowness) must and will change. To my knowledge, the W3C has been working on its transparency problems for at least two years and making real change-just very slowly (theres that word again) and incrementally and hence not at all obviously.. Key decision makers within the W3C intend to do much more, but they need to get their colleagues on board, and consensus-building is a bitch. A slow bitch.. If ...
is a personal favorite of mine: a thriller only a geek could write (Sundman has decades of experience in computer programming), with real characters, frenetic action and suspense, salty dialog, and serious ideas behind the hot cyber action. If Dan Brown read Sundman, he would understand that thrillers about ideas dont have to be claustrophobic, one-dimensional, and absurd. If he took Sundman to heart, he would write better books, although they would sell fewer copies.. Which brings it back to you. Sundman is a brilliant author who, for political, intellectual, or other reasons shuns mainstream publishing and success. If we are to keep enjoying his works, we need to help him realize them. I was proud to contribute to ...
Thankfully, Romesberg and his team have no intention of using their research to provoke some kind of explosion of new, hybrid life forms. As Romesberg told Reuters, his X and Y nucleotide bases cant bond with DNAs natural bases, nor can these semi-synthetic organisms (SSOs) survive outside a laboratory setting. "They cant escape," Romesberg said. "Theres no Jurassic Park scenario ...
Exif Keywords: Natur, nature, animals, Tiere, Anura, Amphibien, Amphibians, Froschlurche, Frogs, Toads, Froesche, Kroeten, Terraristik, Terraristic, Vivarium, ...
Linnaeus, C. 1758. Systema Naturae per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, Tomus I. Editio decima, reformata. Holmiæ: impensis direct. Laurentii Salvii. i-ii, 1-824 pp doi: 10.5962/bhl.title.542: page 212. ...
The 69M pressure switch is used to regulate tank pressure between two preset valves on small (up to 175 psi) electrically driven air compressors.
La pintura y el arte ha magnificado hasta hoy la inmovilidad del pensamiento, el éxtasis y el sueño, nosotros queremos exaltar el movimiento agresivo, el insomnio febril, la carrera, el salto mortal, la bofetada y el puñetazo ...
We are extremely pleased to have attracted a group of world-renowned leaders to one of our key focus areas, atrial fibrillation" said Robert Fischer, MD, CEO of OMEICOS. "The addition of these seasoned experts to OMEICOS Clinical Advisory Board is a testament to the potential of our program and we look forward to their invaluable scientific and clinical development expertise as we shape our strategy to develop an effective therapeutic to achieve long term rhythm control in patients with AF.". Dr. Leonardo Calóis focused on studying cardiac arrhythmias, electrophysiology and ablation and is an expert in the functional role played by omega-3 fatty acids in the prevention of arrhythmias in different settings. He is a Fellow of the European Society of Cardiology and has participated in several international clinical trials. He is associated Editor of Journal of Cardiovascular Interventional Electrophysiology and European Journal of Preventive Cardiology, has authored or co-authored numerous papers ...
474. Bianchini, A. and Wood, C.M. (2008) Sodium uptake in different life stages of crustaceans: The water flea Daphnia magna Strauss. J. Exp. Biol. 211 pp: 539-547. (PDF). ...
Water flea eye. Polarised light micrograph of the eye of a Sida crystallina water flea. Water fleas (order Cladocera) are small crustaceans, commonly found in fresh water. They are filter feeders that ingest algae, protozoa or organic matter, and are a constituent of plankton. Magnification: x400 when printed 10 centimetres wide. - Stock Image C028/9152
article{2094443, author = {Nguyen Thi Hong, Lien and Muyssen, Brita and Janssen, Colin}, issn = {0045-6535}, journal = {CHEMOSPHERE}, keyword = {Hyalella azteca,Zinc,Sediment toxicity,Dietary exposure,Selective feeding,ACID VOLATILE SULFIDES,SIMULTANEOUSLY EXTRACTED METALS,FRESH-WATER INVERTEBRATES,TOXICITY TESTS,BOUND METALS,NEANTHES-ARENACEODENTATA,AQUATIC INVERTEBRATES,REPRODUCTIVE TOXICITY,AVOIDANCE-RESPONSE,SPIKED SEDIMENTS}, language = {eng}, number = {1}, pages = {84--90}, title = {Single versus combined exposure of Hyalella azteca to zinc contaminated sediment and food}, url = {http://dx.doi.org/10.1016/j.chemosphere.2011.11.066}, volume = {87}, year = {2012 ...
We analyzed a large data set of laboratory experiments to examine the effects of cyanobacteria containing or lacking intracellular toxic metabolites and of different morphology on zooplankton population growth rates across multiple genera and species of cladocerans, rotifers and cyanobacteria. Twenty-one of the 29 zooplankton species maintained positive growth rates when fed a diet containing cyanobacteria even though cyanobacteria were a poor food source for half of the zooplankton species tested relative to a diet containing only green algae and/or flagellates. Differences among zooplankton species could not be explained by grazer species body lengths, even when experiments were restricted to those that used only filamentous cyanobacteria. Single-celled cyanobacteria were more detrimental to a larger number of zooplankton species compared to filamentous or chroococcoid colonial cyanobacteria. We also found no clear effect of putative cyanobacterial toxins on the growth of seven zooplankton ...
The common evergreen dwarf shrub Empetrum hormaphroditum has influence on the functioning of boreal terrestrial ecosystems in northern Sweden. The negative effects of E. hermaphroditum are partly attributed to the production of the dihydrostilbene, batatasin-III, which is released from leaves and litter by rain and snowmelt. In this study, we investigated whether batatasin-III is carried by runoff into streams and lakes during the snowmelt period and whether it is also potentially hazardous to aquatic fauna. Sampling of water from streams and a lake for which the surrounding terrestrial vegetation is dominated by E. hermaphroditum was done during the snowmelt period in May 1993 and in 1998, and analyzed for batatasin-III. Using 24- and 48-hr standard toxicity tests, we analyzed toxicity to brown trout (Salmo trutta) alevins and juvenile water fleas (Daphnia magna). Toxicity (proportion of dead individuals) to trout was tested at pH 6.5 and compared with that of a phenol within a range of ...
Microcrustacean emergence from the dry sediments is an important colonization pathway that allows these microfauna to recover and repopulate temporary aquatic habitats after months or years of dryness. Viable microcrustacean propagules in sediments of three different temporary aquatic habitats - rainpools located within the rarely flooded portions, frequently flooded floodplains and rarely flooded floodplains - were assessed experimentally by flooding the soils. Three major groups of microcrustaceans - cladocerans, copepods and ostracods - emerged from the sediments. Species richness and mean total numbers of emerged microcrustaceans per sample varied across the studied temporary aquatic habitats (Kruskal-Wallis, p , 0.05). Both species richness and mean total number of emerged microcrustacean per sample were lowest in sediments of rarely flooded floodplains. The highest species richness of microcrustaceans emerged from the treatments with soils of the frequently flooded floodplains. The mean ...
Discussion Our study suggests that local and regional processes interact to produce patterns of species composition and diversity of zooplankton in Kasseb Reservoir. In this system of highly connected reservoirs, Kasseb Reservoir provides the water for the Ghdir El Goulla Reservoir (Sellami et al., 2009). Connections between reservoirs can have positive and negative impacts on zooplankton communities. The Kasseb Reservoir has low diversity (8 zooplankton species). The results of this study suggest that this system is structured according to the species-sorting paradigm (Leibold et al., 2004). Connectivity can promote high community diversity by providing new species from the regional pool, but can also limit local diversity by washing out species, setting up local communities for competitive exclusion, and otherwise providing a disturbance that can offset equilibrium conditions (Cottenie and DeMeester, 2005).. The highest zooplankton densities were found in early September at a depth of 5 m ...
Coupling of physical, biological and chemical processes associated with particle resuspension and seston flux was investigated at three sites in the North Sea with contrasting water column (mixed/stratified) and seabed (cohesive/non-cohesive) characteristics. Seston concentration was determined by a combination of local resuspension and advection of a regional horizontal concentration gradient. Model simulations of observations show that fair weather, the bed erosion rate was limited by the availability of suitable bed material. The resuspended particles were derived from a surficial veneer of material (fluff) that was relatively enriched in organic carbon. Sediment from the bed itself was therefore not resuspended by tidal currents even at a shallow water, sandy site. Bioturbation of the seabed by infauna significantly modified the properties of muddy sands at a deep water site in summer, but this was insufficient to cause tidal entrainment of the bed sediment. Resuspension increased under ...
Earthworms and tiny water fleas could help deliver clean water to billions of people in remote areas of the world by eating up sewage and other pollution.
However, the actual feeding mechanisms employed by different zooplankters exert an overriding primary control that of food particle acquisition. It is in this context that we primarily attribute Ceratiums influence on zooplankton composition favouring Bosmina and calanoid copepods, while inhibiting Daphnia and Moina (as explained below).. Bosmina has been characterised as an undergrowth taxon able to find and feed on diffuse small food particles (including bacteria) in a nutritional environment overwhelmed by large, mostly inedible particles (Sommer et al., 1986). Similarly, the raptorial feeding mechanism of calanoid (and cyclopoid) copepods allows them to very selectively locate scarce suitable food particles (Koehl and Strickler, 1981; Strickler, 1984; Vanderploeg and Paffenhofer, 1985; Paffenhofer and Lewis, 1990; Brandl, 1998). Conversely, Daphnia employs non-selective bulk filtration, a mode of food collection that greatly compromises it when suspended particles are predominantly ...
3a. Corylus cornuta subsp. cornuta Beaked hazel Corylus cornuta var. megaphylla Victorin & J. Rousseau; C. rostrata Aiton. Shrubs , open spreading, to (4--)6 m. Bark light brown, smooth. Branches ascending; twigs glabrous to sparsely pubescent, without glandular hairs. Winter buds containing inflorescences ovoid, 3--5 × 3--4 mm, apex acute. Leaves: petiole glabrous to moderately pubescent, without glandular hairs. Leaf blade ovate to obovate or narrowly elliptic, often nearly angular and lobulate near apex, 5--12 × 3.5--9 cm, base narrowly cordate to narrowly rounded, margins coarsely and often irregularly doubly serrate, apex usually distinctly acuminate; surfaces abaxially glabrous to moderately pubescent, usually pubescent on major veins and in vein axils. Inflorescences: staminate catkins usually in clusters of 2--3, 4.5--6 × 0.5--0.8 cm; peduncles mostly 0.5--2 mm. Nuts in clusters of 2--6; involucral tubular beak long, narrow, 2--3(--4) times length of nuts, densely bristly. 2 n = 22, ...
Metabolic and stoichiometric theories of ecology have provided broad complementary principles to understand ecosystem processes across different levels of biological organization. We tested several of their cornerstone hypotheses by measuring the nucleic acid (NA) and phosphorus (P) content of crustacean zooplankton species in 22 high mountain lakes (Sierra Nevada and the Pyrenees mountains, Spain). The P-allocation hypothesis (PAH) proposes that the genome size is smaller in cladocerans than in copepods as a result of selection for fast growth towards P-allocation from DNA to RNA under P limitation. Consistent with the PAH, the RNA: DNA ratio was , 8-fold higher in cladocerans than in copepods, although fast-growth cladocerans did not always exhibit higher RNA and lower DNA contents in comparison to slow-growth copepods. We also showed strong associations among growth rate, RNA, and total P content supporting the growth rate hypothesis, which predicts that fast-growing organisms have high P ...
Toxicity tests are most frequently conducted on organisms derived from laboratory cultures that have been reared for many generations following standardized protocols. The restricted density of laboratory populations and the possibility of occasional population crashes increases the probability that random genetic drift and inbreeding may decrease genetic variation of the culture below that typically found in natural populations of the species. Likewise, isolation of organisms in different laboratories may contribute to significant genetic differentiation among culture populations... In the situation where certain genotypes are more resistant to a particular stressor, using a culture that is dominated by the resistant genotype may underestimate the toxic effect of a contaminant. Similarly, the inclusion of a greater number of sensitive genotypes in a test may overestimate toxicity. This experiment was conducted to test the null hypothesis that no difference in tolerance to zinc contamination ...
Lypha dubia (Fall.)(Dipt.: Tachinidae) as a Parasite of the European Pine Shoot Moth,Rhyacionia buoliana (Schiff.)Lep.: Eucosmidae) in ...
The last ten years have witnessed increasing interest in host-pathogen interactions involving invertebrate hosts. The invertebrate innate immune system is now relatively well characterised, but in a limited range of genetic model organisms and under a limited number of conditions. Immune systems have been little studied under real-world scenarios of environmental variation and parasitism. Thus, we have investigated expression of candidate innate immune system genes in the water flea Daphnia, a model organism for ecological genetics, and whose capacity for clonal reproduction facilitates an exceptionally rigorous control of exposure dose or the study of responses at many time points. A unique characteristic of the particular Daphnia clones and pathogen strain combinations used presently is that they have been shown to be involved in specific host-pathogen coevolutionary interactions in the wild. We choose five genes, which are strong candidates to be involved in Daphnia-pathogen interactions, ...
The spiny water flea lives in Lake Michigan and possibly some inland lakes. It uses swimming antennae to move in the water. As it grows, it sheds the outer shell over its body, but not over its spine. The barbed tail spine makes it difficult for predators to swallow this organism, and, after attempting to eat it, they often spit it back out. The life span of the spiny water flea lasts several days to about two weeks. Adults are present in water bodies from late spring until fall. This crustacean may produce up to 10 offspring every two weeks. Most of the spring, summer and fall populations are comprised of females. These adult females produce unfertilized eggs that develop into female offspring that are identical to the mother. This cycle continues as long as the water temperature is not too hot or too cold and food is plentiful. When the water temperature begins to cool in the fall, both males and females are produced, allowing sexual reproduction to occur. Eggs are then deposited over the ...
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