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1.
Typically, the most abundant group of shrimp larvae in the German Bight is formed by representatives of the family Crangonidae.
Larvae of the remaining species have been largely ignored, and only scarce information concerning their ecology is available.
Thus, the purpose of the present study was to determine the species composition, distribution and abundance of noncrangonid
shrimp larvae in the German Bight in July 1990, after the mildest winter of the century. The material is based upon plankton
samples collected at 77 stations, covering the entire German Bight. Eight species were identified, as well as larvae of Palaemonidae
andProcessa-juveniles.Processa nouveli holthuisi (53.0%) andP. modica (31.3%) were predominant in the collection. The distribution of the two species was clearly separated: the main concentration
ofP. nouveli holthuisi (peak concentration of 1.94 larvae per m3) was confined to the northwest corner of the German Bight, while a majority ofP. modica larvae (peak concentration of 0.54 larvae per m3) occurred at the southwesterly stations. The spatial distribution ofCaridion steveni andEualus occultus around Helgoland indicates the presence of an adult population at the only rocky island in the study area. Other taxa, such
as larvae of Palaemonidae and juvenilePandalina brevirostris were collected exclusively in estuarine habitats. Based upon both the results of the present study and comparable data, we
conclude that developmental stages of ten non-crangonid species, as well as representatives of Palaemonidae, can be expected
to occur in the plankton of the German Bight. The extremely mild temperatures of the preceding winter may have been, in part,
responsible for the relatively high densities of some taxa encountered during our plankton survey. We assume that warm winter
temperatures favour the immigration, reproduction and survival of cold-sensitive species. 相似文献
2.
Amir Neori 《Journal of applied phycology》2011,23(1):143-149
Freshwater fish culture is generally considered the largest sector in world aquaculture. Several of the leading species consume
“green water” plankton. This plankton—mostly microalgae (phytoplankton) and also bacteria, protozoa and zooplankton—grows
in man-made fertilized water impoundments. The quantity of “green water” microalgae consumed by fish and shrimp is estimated
here at a quarter billion ton fresh weight a year, about three and a half times as much as the entire recognized aquaculture.
This estimate is based on the quantities of the microalgae consumed and the efficiencies of their use for growth by the main
species in aquaculture. The cost of producing “green water” microalgae by the aquaculturists—mostly in SE Asia—is low. The
populations in “green water” are biologically managed by the cultured fish themselves. The fish with their different feeding
habits help “manage” the composition of the plankton and the overall water quality as they grow. The aquaculturists further
manage “green water” through simple means, including water exchange and fertilization. Cost is remunerated partially by the
income from sales of the fish and partially by bio mitigation services that “green water” polyculture ponds provide the aquaculturists
in treating farm and household waste. A comprehension of the scale and importance of the microalgae sector to world aquaculture
should lead to more research to improve understanding of algal population dynamics, growth factors, and efficiency of food
chains. The consequent improved control of the plankton’s interaction with fish and shrimp production in “green water” will
undoubtedly contribute much to the expansion in production of seafood. 相似文献
3.
Rocket line immunoelectrophoresis was used to study the taxonomy ofAzotobacter andAzomonas assessed by reaction with antiserum to the AVO2 strain ofAzotobacter. Forty-five cultures, comprising seventeen species in five genera, showed that antigen “β”, like high-titer somatic agglutination,
was restricted to all 11 strains ofAzotobacter vinelandii and to one strain which has been namedAzotobacter macrocytogenes (10EM). A thermoresistant antigen (“γ”) was found to be shared by all strains and species ofAzotobacter andAzomonas investigated. 相似文献
4.
In the population “Herrenmühle” ofChironomus plumosus 11% of the individuals contain one supernumerary chromosome. This B-chromosome is present both in germ-line and somatic cells.
— InChironomus melanotus 6% of the larvae of the population “Falkau” carry supernumerary chromosomes. These B-chromosomes cannot be found in all nuclei
of testis and soma, their number varies between cells within the individual. In both species the B-chromosomes represent centromeric
fragments of chromosome IV as can be shown by their structure and pairing behaviour. — The polytene B-chromosome ofCh. plumosus exhibits a banding pattern in the salivary gland nuclei. Furthermore it is able to form an additional nucleolus in the nuclei
of the malpighian tubules. InCh. melanotus band structures can be seen only in the B-chromosome of malpighian tubules. The larvae ofCh. melanotus, carrying B-chromosomes, show heterochromatic bodies in the salivary gland nuclei, varying in number and size in the nuclei
of the same gland. These bodies are interpreted to be polytenic B-chromosomes divided into subunits.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
5.
Ingo S. Wehrtmann 《Helgoland Marine Research》1989,43(1):87-112
Plankton samples were collected from January 1985 to January 1986 three times per week at Helgoland to study seasonal occurrence
and abundance of caridean shrimp larvae. A total of eleven species were obtained. Ninety-one % of all larvae collected during
the sample period belonged toCrangon crangon L. andCrangon allmanni Kinahan, 6% toPhilocheras trispinosus Hailstone and 3% to the remaining eight species. Collections were generally dominated byC. crangon larvae. However,C. allmanni larvae were most abundant in June coinciding with hatching activities of the population near Helgoland.C. allmanni was observed to have the highest density of all species with approximately 8 larvae per m3. Larvae ofEualus occultus (Lebour),Eualus pusiolus (Kroyer),Hippolyte varians Leach andAthanas nitescens Leach were most likely released by populations inhabiting the rocky intertidal zone around Helgoland. The presence ofProcessa modica Williamson & Rochanaburanon andProcessa nouveli holthuisi Al-Adhub & Williamson in the German Bight was verified by observations of a series of different developmental stages. Larvae
of the rare speciesCaridion steveni Lebour were also recorded. The observed shrimp species were placed into three different groups with respect to their seasonal
occurrence. Possible advantages of the timing of larval dispersal relative to predation and food availability are given. The
results on seasonal occurrence and relative abundance are discussed in relation to environmental factors (temperature, salinity)
as well as to the geographical distribution of the species. 相似文献
6.
The human impact in the German Bight, in the form of anthropogenic eutrophication, has been documented by a 30-year time-series
measurement near the island of Helgoland. Since 1962, the Biologische Anstalt Helgoland has measured inorganic nutrients and
phytoplankton abundance from daily samples at Helgoland Roads, a position 60 km off the main source of eutrophication, the
River Elbe. Since the early sixties, phosphate concentrations rose for about a decade, levelling off to about twice the former
concentrations for another decade, and then decreasing (since 1982) as a result of phosphate-reducing measures. Nitrate concentrations,
however, have only increased since 1980/81, following Elbe river flood events. In 1987, three times the former concentrations
were reached. A decrease has been observed only since 1991. This different development of phosphorus and nitrogen eutrophication
led to a shift of inorganic N/P-ratios in the German Bight. The phosphate increase was more pronounced in the late summer
“regeneration mode” conditions, the nitrate increase in the winter months. The eutrophication is not restricted to the inner
German Bight and coastal waters of a salinity of <33, but has also occurred in more saline waters at S>33 psu (practical salinity
unit), as characteristic for the outer German Bight. In this more saline water, phosphate and nitrate maximum levels occurred
three years later, compared with the average Helgoland data, which are more representative of the inner German Bight. It is
suggested that suspended particulate organic matter, as a long-distance carrier of nutrients, might have caused this delayed
eutrophication in the outer German Bight waters. While the human impact is obvious as to nutrient concentrations, it is less
obvious in phytoplankton stock enhancement. A general increase in phytoplankton biomass (about 3–4 times) was found, but this
was mainly due to unidentified nanoflagellates of unknown trophic state, and subject to methodological errors. The causal
relationships of phytoplankton stocks and eutrophication are not clearly understood, as natural variability is large and hydrographical
factors possibly dominate. Additional nutrient input by Elbe river floods did not always result in elevated phytoplankton
stocks near Helgoland, while extended periods of vertical density stratification of the German Bight water caused large plankton
blooms. 相似文献
7.
Jonathan J. Henry 《Development genes and evolution》1989,198(3):129-136
Summary The light emitting photocytes ofChaetopterus variopedatus larvae are bilaterally situated within the ectoderm of the post-trochal region. Their histological appearance is similar
to that of the adult photocytes. The larval photocytes contain a large quantity of membranous secretory vesicles (photosomes),
which probably contain the photoluminescent protein. The two-cellChaetopterus embryo contains a small AB and a large CD blastomere. Previous studies have shown that only the “larvae” resulting from isolated
CD blastomeres are able to luminesce. Consistent with these findings, morphologically distinct photocytes are only found in
the CD larvae. The removal of the small polar lobe that forms during first cleavage leads to the production of a “larva” that
is unable to produce light. All delobed larvae contain morphologically distinct photocytes, which are identical to those in
normal larvae except they appear to contain only a small quantity of photosomes. Experimental equalization of first cleavage
leads to the production of a double embryo. While photocytes are found in both of the duplicated post-trochal regions, usually
only one of these is capable of emitting luminescence. Apparently, the highly localized vagetal material (determinants) responsible
for functional light emission is distributed to both halves in only a few cases when first cleavage is experimentally “equalized”.
These results indicate that the determinative action of the polar lobe is not required for the formation of the photocytes
themselves, but rather for their ability to function as emitters of light. The determinants in the polar lobe ofChaetopterus may control some aspect of the photoluminescence reaction itself, such as the production of the photoprotein. 相似文献
8.
Field grown foliage from the resistant soybean [Glycine max (L.) Merrill] breeding line GAT “81–327” and the susceptible cultivar “Ransom” was used to rear unparasitized larvae of the
soybean looper (SBL),Pseudoplusia includens (Walker), and larvae parasitized byCopidosoma truncatellum (Dalman). SBL larvae, whether parasitized or not, consumed more foliage when fed “Ransom”. Unparasitized larvae reared on
“81–327” had longer developmental times and suffered greater mortality than unparasitized larvae reared on “Ransom”. Parasitization
of SBL larvae byC. truncatellum increased total foliage consumption of both soybean lines. Parasitized larvae reared on the resistant “81–327” weighed less
and yielded fewer parasitoid adults.
Résumé Des larves dePseudoplusia includens (Walker) parasitées ou non parCopidosoma truncatellum (Dalman) ont été nourries des feuilles de deux lignées de soja [Glycine max (L.) Merrill] l'une, GAT “81–327” résistante et l'autre, “Ransom” sensible. Les larves deP. includens qu'elles soient parasitées ou non consommaient plus de feuillage lorsqu'elles étaient nourries de la lignée “Ransom”. Les larves non parasitées élevées sur “81–327” avaient un cycle de développement beaucoup plus long et un taux de mortalité beaucoup plus élevé que les larves non parasitées élevées comparativement sur feuilles de “Ransom”. Par contre, les larves parasitées manifestaient une consommation accrue du feuillage des deux lignées de soja. Les larves parasitées élevées sur les feuilles de la variété résistante GAT “81–327” pesaient moins et produisaient moins également de parasites adultes.相似文献
9.
P. Martens 《Helgoland Marine Research》1995,49(1-4):553-562
A statistical analysis was performed to determine environmental factors of significant influence on the mesozooplankton in
the northern Wadden Sea of Sylt (German Bight) in 1991. The total mesozooplankton (>76 μm) was significantly correlated with
water temperature as was the case with the calanoid copepodAcartia sp.;Pseudo- andParacalanus sp. were influenced by the amount of rainfall, whereas the amount of the meroplanktonic larvae of the cirripedia was related
to the amount of particulate organic nitrogen in the water. A comparison of the years 1984 and 1991 demonstrates the positive
effect of temperature on the copepod speciesAcartia sp. in summer. 相似文献
10.
Ellis L. Yochelson 《Pal?ontologische Zeitschrift》2002,76(2):297-304
Dentalium antiquum is one of two moderately well-known Devonian “scaphopods” in the German literature. Examination of the type material and
a few specimens in other institutions indicates more individual variability than is to be expected in species of the molluscan
class Scaphopoda. The species is transferred with question toColeolus
Hall, a fossil presumed to be a calcareous “worm” tube.
相似文献
11.
Yuzuru Hamada 《Primates; journal of primatology》1984,25(4):485-506
A method based on the Fourier analysis is proposed, which describes and analyzes the contour morphology of carpal bones by
separating morphology into factors of shape and size. Here, “size” refers to the average diameter of the contour. The “shape”
is expressed byshape factors which are derived from the Fourier series and the “shape” of a monkey is expressed by ashape index which is calculated fromshape factors. The age change in the morphology of the lunate and capitate ofMacaca fuscata fuscata was analyzed by this method. The development of “shape” approximately completes by 3 years of age, whereas increase in “size”
begins its spurt at that age as do body weight and anterior trunk length. By applying this method to other macaque species,
it was found thatM. mulatta, M. f. yakui andM. cyclopis exhibit similar patterns of growth and development of carpal bones to those ofM. f. fuscata. Patterns found inM. fascicularis differ in that its bones develop faster than in the other macaques with respect to the “shape,” but remain small with respect
to the “size.” 相似文献
12.
Dr. Erich Kessler 《Plant Systematics and Evolution》1985,151(1-2):67-71
The upper limit of temperature for growth is a species-specific character in the genusChlorella. The limits of 14Chlorella species range from 26–30°C (C. saccharophila) to 38–42°C (C. sorokiniana), withC. fusca var.vacuolata (34°C) andC. kessleri (34–36°C) assuming an intermediate position. Thus, there is no wide gap in the temperature limits between the normal (“low-temperature”)
species ofChlorella and the “high-temperature” species,C. sorokiniana. 相似文献
13.
Patrick J. Brennan 《Journal of biosciences》1984,6(5):685-689
There is now a considerable body of evidence to suggest that the phthiocerol-containing lipids, including the phenolic glycolipids,
comprise the so-called “peribacillary substance”, “spherical droplets”, “foamy structures” and “capsular materials” ofMycobacterium leprae. Thus, the phthiocerol-containing lipid capsule may be directly responsible for the intracellular survival ofMycobacterium leprae. 相似文献
14.
Keith Johnson 《Journal of biological physics》2012,38(1):85-95
Water nanoclusters are shown from first-principles calculations to possess unique terahertz-frequency vibrational modes in
the 1–6 THz range, corresponding to O–O–O “bending,” “squashing,” and “twisting” “surface” distortions of the clusters. The
cluster molecular-orbital LUMOs are huge Rydberg-like “S,” “P,” “D,” and “F” orbitals that accept an extra electron via optical
excitation, ionization, or electron donation from interacting biomolecules. Dynamic Jahn–Teller coupling of these “hydrated-electron”
orbitals to the THz vibrations promotes such water clusters as vibronically active “structured water” essential to biomolecular
function such as protein folding. In biological microtubules, confined water-cluster THz vibrations may induce their “quantum
coherence” communicated by Jahn–Teller phonons via coupling of the THz electromagnetic field to the water clusters’ large
electric dipole moments. 相似文献
15.
C. M. M. Meireles M. I. C. Sampaio H. Schneider M. P. C. Schneider 《Primates; journal of primatology》1992,33(2):227-238
The electrophoretic patterns of 15 protein systems codified for 20 genetic loci were investigated using horizontal electrophoresis.
A total of 150 blood samples, from five species of the genusCallithrix were analyzed. Polymorphic variation was observed in 10 out 20 loci analyzed. The genotypic distributions are in Hardy-Weinberg
equilibrium. The average heterozygosity (H) varied from 1% to 5%, similar to those observed for other Neotropical primates.
The genetic distance coefficients revealed a phylogenetic separation of these species into two groups: (1) “argentata” (C. humeralifer andC. emiliae); (2) “jacchus” (C. jacchus, C. penicillata, andC. geoffroyi). This arrangement is according to the taxonomic arrangement proposed byHershkovitz (1977),de Vivo (1988), andMittermeier et al. (1988). The results in each group are compatible with the subspecies values recorded for the Platyrrhini. These values
showed that:C. humeralifer andC. emiliae are subspecies ofC. argentata;C. jacchus, C. penicillata, andC. geoffroyi are subspecies ofC. jacchus. These results also suggest thatC. j. geoffroyi is the “jacchus” group taxon, most similar genetically to the “argentata” group. 相似文献
16.
Gathered food plants in the mountains of Castilla-La Mancha (Spain): Ethnobotany and multivariate analysis 总被引:1,自引:0,他引:1
Diego Rivera Concepción Obón Cristina Inocencio Michael Heinrich Alonso Verde José Fajardo José Antonio Palazón 《Economic botany》2007,61(3):269-289
Gathered food plants (GFPs) (wild and weeds) are crucial for understanding traditional Mediterranean diets. Combining open
interviews and free-listing questionnaires, we identified 215 GFP items, i.e., 53 fungi and 162 from 154 vascular plant species.
The variation in frequency and in salience among the items follows a rectangular hyperbola. Highly salient species were Silene vulgaris (Moench) Garcke, Scolymus hispanicus L., and Pleurotus eryngii (DC.: Fr.) Quélet. Salience and frequency showed no correlation with the expected health benefits of each species. Regional
frequency in the Mediterranean and local frequency are directly related. Thus, local food plants are much less “local” than
expected.
Different types of culinary preparations provide the most information in the cluster analysis of variables. The cluster analysis
of items produced a tree with 10 clusters that form culture-specific logical entities, allowing people to structure their
environment. Within each cluster, plant species are replaced and incorporated provided they resemble the general profile.
This allows innovation and adaptation on a local level and explains the differences between adjacent localities in the list
of species. Two types of clusters or species complexes are described: “species-labeled” and “uses-labeled.” Lastly, we discuss
the underlying empirical basis of the ethnoclassification in the Mediterranean area. 相似文献
17.
The finding ofErwinia herbicola (Enterobacter agglomerans) in blood cultures of 15 inpatients, during a 53/4-year period in a nonepidemic context, was analyzed for clinical significance.
Mixed cultures were seen in 5 patients; multiple sets were taken in 10 patients. In only 6 patients couldErwinia be significantly correlated with clinical septicemia; in 9, it was of doubtful significance, more likely reflecting transient
bacteremia than skin contamination or laboratory handling. These findings contrast to previous reports that stress a preponderance
of clinically significant strains ofEnterobacter species andErwinia from blood cultures. The only bacteriological differences between the “significant” and “doubtful” groups involved the time
required to detectErwinia. 相似文献
18.
Phenetic analyses of 218 OTUs belonging toVaccinium sectionMyrtillus and scored for 13 characters generated five robust clusters.Vaccinium parvifolium is the most distinct cluster, followed by the “myrtillus-scoparium” complex, thenV. membranaceum, V. caespitosum, and the “ovalifolium-deliciosum” complex. Biosystematic studies suggest that the five clusters comprise seven taxa that possess many of the properties that
define biological species. Indeed, the recognition of the seven taxa as species is supported by cytological, phenological,
biogeographical and ecological as well as chemical data. A detailed taxonomic treatment for all these taxa is presented. 相似文献
19.
Two associated partial skeletons, one from the McCarty ranch (MOTTU site 0690) near Kalgary, Texas, Tecovas Formation, and
the other from the Petrified Forest Member of the Chinle Formation, outside the Petrified Forest, Arizona, represent the most
complete specimens ofPoposaurus gracilis found to date, and increase our understanding of the osteology of this rare pseudosuchian archosaur. The cervical centrum
of TTUP-10419 possesses an accessory dorsal parapophyseal rib facet, as in “Lythrosuchus”. The ilia of these new fossils are the first ofPoposaurus to preserve the complete preacetabular blade, which is long and “blade-like” rather than “paddle-shaped” as previously thought.
These specimens also confirm that isolated elements previously referred toPoposaurus (fused sacral vertebrae, the pubes and the ischia), but not present in the holotype indeed belong to that taxon. The morphology
of the cervical centrum and the preacetabular blade of the ilium are identical to the much larger type of“Lythrosuchus” langstoni, suggesting that “Lythrosuchus” is a junior synonym ofPoposaurus. However, we retain the speciesPoposaurus langstoni nov. comb. on the basis of larger size, absence of a distinct ridge on the lateral surface of the ilium, and the lack of
a pit on the proximal end of the ischium. A phylogenetic analysis suggests a monophyletic Poposauroidea and a paraphyletic
“Rauisuchia”. 相似文献
20.
Four strains of the phytopathogenic bacteriumCorynebacterium fascians (Tilford)Dowson were selected from our isolates and deposited in the Czechoslovak National Collection of Type Cultures (CNCTC) of the Institute
of Hygiene and Epidemiology in Prague. Two very virulent (Cor 83/82 “UPR” and Cor 82/81 “UP”) and one avirulent (Cor 81/80
“CP1b”) pelargonium strains, producing acid from rhamnose, were isolated from fasciations onPelargonium zonale W. One avirulent celery strain ofC. fascians (Cor 80/80 “CF4a”) was isolated from a root expiant ofApium graveolens L. growing on a nutrient mediumin vitro. Morphological, cultural, physiological and biochemical characteristics of these selected Czechoslovak isolates were compared
with the American patented strain cotype ATCC 12974. 相似文献