Seasonal and Annual Variations in Quantity of Pelagic Net Plankton, Cultus Lake, British Columbia

1938 ◽  
Vol 4a (1) ◽  
pp. 33-47 ◽  
Author(s):  
William E. Ricker
Keyword(s):  
Environmental Conditions ◽  
Dry Weight ◽  
Common Species ◽  
Early Spring ◽  
Seasonal Distribution ◽  
Fish Food ◽  
Annual Variations ◽  
Annual Changes ◽  
Spring Maximum ◽  
Definite Correlation

Intermittently over a 13 year period the net plankton of Cultus lake has been sampled, at a central representative station. Net plankton was not particularly rich in common species. Of the entomostracans important as fish food, only four occurred. Seasonal distribution of the various species is of two principal kinds: unimodal, with one peak of abundance in late spring or summer—various green algae, Protozoa, Rotatoria, Cladocera and Epischura; and bimodal with peaks in early spring and in autumn—diatoms, mostly Rotatoria and Cyclops. Among bimodal species the spring maximum is ordinarily the greater. Marked differences in abundance of a plankter occur from year to year and affect both the maximal numbers attained and duration of time of proliferation. The available data do not show these annual changes to be cyclic and no definite correlation with environmental conditions has been made. The total nitrogen content of net plankton varied from 2 to 10 mg. per l. in 1932, the dry weight from 30 to 210 mg.

Function of coprophagous beetles (Coleoptera: Scarabaeidae, Geotrupidae, Hydrophilidae) in cattle pastures inferred from pitfall trapping data

2010 ◽  
Vol 27 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Martin Šlachta ◽  
Jan Frelich ◽  
Tomáš Tonka
Keyword(s):  
Seasonal Variation ◽  
Spatial Variation ◽  
Dry Weight ◽  
Seasonal Distribution ◽  
The Other ◽  
Pitfall Trapping ◽  
Other Hand ◽  
Nested Anova ◽  
Species Groups ◽  
Dung Decomposition

Function of coprophagous beetles (Coleoptera: Scarabaeidae, Geotrupidae, Hydrophilidae) in cattle pastures inferred from pitfall trapping dataAn analysis of data on the dry weight biomass of coprophagous beetles in standardized dung (4.5 l) was conducted in order to characterize the spatial and the seasonal distribution of the beetles' biomass in cattle pastures and to elucidate their function in dung decomposition. Nested Anova with factors of farm, site (nested in farm), seasonal period and year was used to evaluate the effect of these factors on the biomass of four functional species groups: the dung dwellers ofScarabaeidae(subfamilyAphodiinae), the dung dwellers ofHydrophilidae, the small tunnellers ofScarabaeidae(subfamilyCoprinae) and the large tunnellers ofGeotrupidae. The spatial variation of biomass (between the sites and the farms) was insignificant (P>0.05) in the two dung-dweller groups and in the large-tunnellers group. On the other hand, a significant (P<0.05) seasonal variation of biomass was found in all but the large tunneller group. In dung dwellers, the spring biomass was formed mainly by two species,Aphodius prodromusandA. sphacelatus. In summer, most of the biomass was accounted for bySphaeridium lunatum, S. scarabaeoidesandA. rufipes. In the two tunneller groups,Onthophagus fracticornis, Geotrupes stercorariusandG. spinigerformed a majority of the biomass in dung.

Observations on moulting in Antarctic Krill (Euphausia superba Dana)

1982 ◽  
Vol 33 (1) ◽  
pp. 71 ◽  
Author(s):  
T Ikeda ◽  
P Dixon
Keyword(s):  
Phaeodactylum Tricornutum ◽  
Antarctic Krill ◽  
Dry Weight ◽  
Euphausia Superba ◽  
Dunaliella Tertiolecta ◽  
Antarctic Ocean ◽  
Fish Food ◽  
Antarctic Waters ◽  
The Antarctic ◽  
Antarctic Krill Euphausia Superba

Live E. superba were transported from Antarctic waters to a tropical laboratory where observations at the temperature of -0.5�C (0 to - 1.0�C), were made of intermoult period of specimens fed a mixture of microalgae (Dunaliella tertiolecta and Phaeodactylum tricornutum) or artificial pet fish food or starved. Mean intermoult period was 26.4-27.1 days for fed specimens and 29.6 days for starved specimens, with no relation to the size of specimens. The moult accounted for a loss of 2.63-4.35% of animal dry weight, which is equivalent to 1.1-1.8% of animal nitrogen or 1.4-2.3% of animal carbon. The contribution of moults to detritus in the Antarctic Ocean was estimated as 0.11 g C m-2 per year.

scholarly journals Intra-Annual Variability of the Radiocarbon Content of Corals from the Galapagos Islands

Radiocarbon ◽  
1993 ◽  
Vol 35 (2) ◽  
pp. 245-251 ◽  
Author(s):  
T. A. Brown ◽  
G. W. Farwell ◽  
P. M. Grootes ◽  
F. H. Schmidt ◽  
Minze Stuiver
Keyword(s):  
Southern Oscillation ◽  
Galapagos Islands ◽  
Ocean Current ◽  
Galápagos Islands ◽  
Ocean Water ◽  
Annual Variations ◽  
Surface Ocean ◽  
Annual Variability ◽  
Annual Changes ◽  
Detailed Record

We report AMS 14C measurements on subannual samples of coral from the Galapagos Islands that span the period, 1970–1973. Both the major 1972 El Niño/Southern Oscillation event and intra-annual changes in regional upwelling of 14C-depleted waters associated with alternation of surface-ocean current patterns are evident in the record. Our data show that the corals preserve a detailed record of past intra-annual variations of the 14C content of surface ocean water.

Annual variations in body-size spectra of planktonic ciliate communities and their relationships to environmental conditions: a case study in Jiaozhou Bay, northern China

2012 ◽  
Vol 93 (1) ◽  
pp. 47-55 ◽  
Author(s):  
Henglong Xu ◽  
Yong Jiang ◽  
Wei Zhang ◽  
Mingzhuang Zhu ◽  
Khaled A. S. Al-Rasheid ◽  
...  
Keyword(s):  
Body Size ◽  
Water Temperature ◽  
Environmental Conditions ◽  
Jiaozhou Bay ◽  
Northern China ◽  
The Body ◽  
The Yellow Sea ◽  
Size Spectra ◽  
Annual Variations ◽  
Planktonic Ciliate

The annual variations in body-size spectra of planktonic ciliate communities and their relationships to environmental conditions were studied based on a 12-month dataset (June 2007 to May 2008) from Jiaozhou Bay on the Yellow Sea coast of northern China. Based on the dataset, the body sizes of the ciliates, expressed as equivalent spherical diameters, included five ranks: S1 (5–35 μm); S2 (35–55 μm); S3 (55–75 μm); S4 (75–100 μm); and S5 (100–350 μm). These body-size ranks showed a clear temporal succession of dominance in the order of S2 (January–April) → S1 (May–July) → S4 (August–September) → S3 (October–December). Multivariate analyses showed that the temporal variations in their body-size patterns were significantly correlated with changes in environmental conditions, especially water temperature, salinity, dissolved oxygen concentration (DO) and nutrients. In terms of abundance, rank S2 was significantly correlated with water temperature, DO and nutrients, whereas ranks S4 and S5 were correlated with the salinity and nutrients respectively (P < 0.05). These results suggest that the body-size patterns of planktonic ciliate communities showed a clear temporal pattern during an annual cycle and significantly associated with environmental conditions in marine ecosystems.

scholarly journals Grain filling parameters in high-yielding ns wheat cultivars

2008 ◽  
pp. 53-58
Author(s):  
Milka Brdar ◽  
Marija Kraljevic-Balalic ◽  
Borislav Kobiljski
Keyword(s):  
Multivariate Analysis ◽  
Nonlinear Regression ◽  
Environmental Conditions ◽  
Dry Weight ◽  
Grain Filling ◽  
Grain Weight ◽  
Cultivar Differences ◽  
Wheat Cultivars ◽  
Estimated Parameters ◽  
Grain Filling Duration

Grain yield of wheat is dependent on grain weight, which is the result of grain filling duration and rate. The study was undertaken to examine the relation between grain weight and rate and duration of grain filling in five high-yielding NS wheat cultivars. Stepwise multivariate analysis of nonlinear regression estimated grain filling parameters was used to examine cultivar differences in grain filling. On the basis of three-year average, the highest grain dry weight had cultivar Renesansa, and the lightest grains were measured for cultivar Evropa 90. Stepwise multivariate analysis indicated that all three nonlinear regression estimated parameters (grain weight, rate and duration of grain filling) were equally important in characterizing the grain filling curves of the cultivars studied, although sequence of their significance varied in different years, which is probably caused by different environmental conditions in three years of experiment.

scholarly journals Convergence in wing coloration between orange underwing moths (Archiearis spp.) and tortoiseshell butterflies (Aglais spp.)

2001 ◽  
Vol 12 (2) ◽  
pp. 65-71 ◽  
Author(s):  
Jens Rydell ◽  
Joakim Fagerström ◽  
Staffan Andersson ◽  
Gabriela Stille ◽  
Magnus Gelang ◽  
...  
Keyword(s):  
Common Species ◽  
Early Spring ◽  
Colour Pattern ◽  
Flight Period ◽  
Defence System ◽  
Bright Orange ◽  
Predator Defence ◽  
Wing Coloration

We analysed the wing coloration of the orange underwing moth Archiearis parthenias (Geometridae, Archiearinae) in comparison with the small tortoiseshell butterfly Aglais urticae (Nymphalidae). Both species fly in early spring and occur sympatrically in the northern Palaearctic. Aglais, the more common species, has a longer flight period and uses a broader range of habitats. Both species show a camouflaged colour pattern on surfaces exposed at rest but a bright orange signal in flight. Although the evolution of its coloration is constrained by its geometrid morphology, Archiearis is functionally similar to Aglais both while resting and in flight. Archiearis has presumably evolved from nocturnal geometrid ancestors. Its shift to diurnality has included a change in the predator defence system from one based on ultrasonic hearing, functional against bats, to one presumably functional against birds. Preliminary palatability tests showed that Aglais is distasteful to birds (chicken), while Archiearis seems to be palatable. The function of the convergent coloration is unknown, but several possibilities are discussed.

Ammonium Sulfate Increases Efficacy of Sethoxydim Through Increased Absorption and Translocation

Weed Science ◽  
1992 ◽  
Vol 40 (3) ◽  
pp. 351-358 ◽  
Author(s):  
Anne M. Smith ◽  
William H. Vanden Born
Keyword(s):  
Ammonium Sulfate ◽  
Environmental Conditions ◽  
Dry Weight ◽  
Model Systems ◽  
Short Term ◽  
Wild Oats

The effect of ammonium sulfate (AMS) on efficacy and on absorption and translocation of sethoxydim in wild oats and barley was investigated under controlled environmental conditions. Increases in efficacy in the presence of AMS were relatively small. The rate of sethoxydim required to reduce dry weight 50% was reduced from 0.08 kg a.i. ha−1, for both species, to 0.07 and 0.06 kg ha−1for wild oats and barley, respectively, in the presence of added AMS. In short-term experiments, uptake of14C from14C-labeled sethoxydim 0.5 and 1 h after application was increased approximately twofold with the addition of AMS. AMS had little effect on sethoxydim absorption beyond 1 h after application. Translocation at 1 h after application was unaffected by AMS. However, translocation 12 and 24 h after application was increased with AMS. It is postulated that the translocation increase results indirectly from the increase in absorption. The observed increase in absorption with the addition of AMS is evident only when crop oil concentrate (COC) is also present In model systems, the addition of AMS enhanced sorption of sethoxydim into Isolated cuticles but had no effect on movement into excised roots.

Biomasse et espèces de lichens terrestres disponibles pour le caribou dans le nord du Québec

1990 ◽  
Vol 68 (10) ◽  
pp. 2047-2053 ◽  
Author(s):  
Michel Crête ◽  
Claude Morneau ◽  
René Nault
Keyword(s):  
Plant Cover ◽  
Ground Cover ◽  
Dry Weight ◽  
Common Species ◽  
The West ◽  
The North ◽  
Precipitation Zone ◽  
Annual Consumption ◽  
Mat Thickness ◽  
Primary Unit

Following a two-stage sampling plan, 44 1-km2 primary units were systematically allocated between 53 and 59 ° latitude throughout northern Québec to estimate the biomass of terrestrial lichens. Lichens were collected in two secondary units (0.25 m2) located in parts of each primary unit where lichens were visible from a helicopter (lichen stratum). Overall, the lichen stratum covered 51% of the study area and lichen biomass averaged 1223 kg/ha (dry weight; SE = 201; n = 44). Almost 85% of the variance of this mean was attributable to variability between primary units. The biomass in the west was greater than in the east; it was the highest in the [Formula: see text]700-mm precipitation zone and the lowest in the 500- to 599-mm zone. Data on percent plant cover indicated mat mosses increased in importance over lichens in the east. There was a clear relationship between lichen biomass in secondary units on one hand and mat thickness and percent lichen ground cover on the other. Cladinia stellaris (Opiz) Brodo was the most common species; Alectoria ochroleuca (Hoffm.) Mass. and Cornicularia divergens Ach. were typical of the north, whereas Cladina mitis (Sandst.) Hustich characterized the south of the study area. The annual consumption of lichens by caribou was probably 0.5-0.9% of the available biomass in 1987. Key words: biomass, caribou, Cladina, lichens, Quebec.

Control of common cocklebur (Xanthium strumarium L.) in corn

2010 ◽  
Vol 90 (6) ◽  
pp. 933-938 ◽  
Author(s):  
N. Soltani ◽  
C. Shropshire ◽  
P.H. Sikkema
Keyword(s):  
Environmental Conditions ◽  
Dry Weight ◽  
Field Trials ◽  
Xanthium Strumarium ◽  
Corn Yield ◽  
Shoot Dry Weight ◽  
Herbicide Treatments ◽  
Excellent Control

Nine field trials (five with PRE and four with POST herbicides) were conducted in 2006 to 2009 on various Ontario farms with heavy common cocklebur infestations to determine the effectiveness of PRE and POST herbicides for the control of common cocklebur in corn. There was no commercially significant corn injury from the PRE herbicides evaluated. Saflufenacil, saflufenacil/dimethenamid-p, isoxaflutole + atrazine, mesotrione + atrazine and dicamba/atrazine, applied PRE provided 85, 85, 76, 73 and 67% control of common cocklebur in corn 8 wk after emergence (WAE), respectively. Common cocklebur shoot dry weight was reduced 84, 80, 79, 75 and 68% with saflufenacil/dimethenamid-p, isoxaflutole + atrazine, mesotrione + atrazine, saflufenacil and dicamba/atrazine, respectively. There was no effect on corn yield compared with the weedy control with the PRE herbicides evaluated. The application of 2,4-D/atrazine POST resulted in unacceptable injury (28%) in corn. Dicamba/atrazine, dicamba/diflufenzopyr, dicamba and mesotrione + atrazine provided up to 98, 95, 90 and 90% control of common cocklebur 8 wk after application (WAA), respectively. All POST herbicide treatments increased corn yield compared with the non-treated control. Saflufenacil and saflufenacil/dimethenamid-p applied PRE and dicamba, dicamba/diflufenzopyr, dicamba/atrazine or mesotrione + atrazine applied POST have potential to provide good to excellent control of common cocklebur in corn under Ontario environmental conditions.

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