scholarly journals Seasonal variation in the vertical distribution of zone over Oakshin Gangotri, Antarctica

MAUSAM ◽  
2021 ◽  
Vol 42 (3) ◽  
pp. 275-278
Author(s):  
A.L. KOPPAR ◽  
S.C. NAGRATH
Keyword(s):  
Seasonal Variation ◽  
Vertical Distribution ◽  
Early Spring ◽  
The Other ◽  
Late Winter ◽  
Double Peak ◽  
The Vertical Distribution

Ozone soundings made from Dakshin Gangotri, Antarctica during 1987 are presented. The vertical distribution of ozone over Antarctica is characterised by a double peak profile, one around 200-150 hPa and the other around 50 hPa. During late winter-early spring the upper peak is considerably depleted. Tropospheric ozoe remains low and nearly constant throughout the year.  

scholarly journals Seasonal variation of the crustacean fauna in the belowground and aboveground strata in a Halodule wrightii meadow of northeastern Brazil

2017 ◽  
Vol 107 (0) ◽  
Author(s):  
Kcrishna V. S. Barros ◽  
Jesser F. Souza-Filho ◽  
Ricardo J. C. Paiva ◽  
Catarina L. Araújo-Silva ◽  
Alexandre O. Almeida ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Seasonal Variation ◽  
Vertical Distribution ◽  
The Other ◽  
Northeastern Brazil ◽  
Halodule Wrightii ◽  
The Vertical Distribution

ABSTRACT The different microhabitats provided by seagrasses and the habit of the species determinate the vertical distribution of crustaceans. This study verified the influence of the seasonality on the spatial distribution of the crustacean community associated with a Halodule wrightii meadow. From April 2006 to July 2007, we performed fifteen samplings in Goiabeiras Beach, Ceará State, each with five sectioned replicates in belowground and aboveground. Cumaceans and the amphipod Hyale media (Dana, 1853) had a higher frequency, density, and dominance than the other taxa, in both strata. The community exhibited gradual changes along the study, in both the belowground and aboveground strata, but the seagrass structure was not sufficient to explain the vertical distribution of the crustacean fauna along the time.

Daily inundation induced seasonal variation in the vertical distribution of soil water salinity in an estuarine mangrove forest under a tropical monsoon climate

2020 ◽  
Vol 35 (4) ◽  
pp. 638-649
Author(s):  
Akira Komiyama ◽  
Sasitorn Poungparn ◽  
Suthathip Umnouysin ◽  
Chadtip Rodtassana ◽  
Shogo Kato ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Vertical Distribution ◽  
Soil Water ◽  
Mangrove Forest ◽  
Water Salinity ◽  
Monsoon Climate ◽  
Tropical Monsoon ◽  
The Vertical Distribution

Reproduction in the Macropod Marsupial Potorous tridactylus (Kerr).

1962 ◽  
Vol 10 (2) ◽  
pp. 193 ◽  
Author(s):  
RL Hughes
Keyword(s):  
Post Partum ◽  
Cell Types ◽  
Early Spring ◽  
The Other ◽  
Late Winter ◽  
Polymorphonuclear Leucocytes ◽  
Marsupial Species ◽  
Heat Period ◽  
Breeding Seasons ◽  
Made In

Thirty-five female Tasmanian rat-kangaroos, Potorous tridmtylus (Kerr), were studied. This marsupial is both polyoestrous and monovular. The length of the oestrous cycle is approximately 42 days (range 39-44 days). Study of vaginal smears over intervals that included 14 oestrous periods revealed that the proportions of cornified cells reached a maximum of over 80% at oestrus, and conversely the other cell types (i.e. nucleated epithelial cells and polymorphonuclear leucocytes) were at minimal concentrations. In four females copulation was apparently permitted at any time during the period of rapid increase in the proportion of cornified cells. One female repeatedly received a male over a 12-day heat period. Copulations were brief and were observed only between 4.00 p.m. and 1.45 a.m. In two females coitus was found to precede ovulation. The gestation period (defined as the interval between copulation and parturition) varied between 30 and 43 days in four animals. In one instance parturition was witnessed 37.5 days after copulations that were restricted to a 12-hr period. A marked increase in pouch vascularity occurred a few hours prior to parturition. Parturition was witnessed on one occasion and is described. The time taken to reach the pouch was 10 min; attachment was made in a further 12 min. On another occasion a neonatus removed from a teat shortly after parturition took 5 min to locate the teat and a further 15 min to complete reattachment. Permanent attachment of the offspring to a teat occupied 64 days in one instanc; in another it lasted 46 days but as the offspring died 6 days later it may be that the teat was vacated prematurely. The manner in which permanent nipple attachment is achieved is discussed and a description of the development of external features of pouch young is given. Nipples increased in both length and diameter during the first 115 days of suckling, after which regresslon began. The regresslon was correlated wlth the process of weanlng. An indication of three successive lactations was obtained from nipple dimensions. Pregnancy (occupying about 38 days) did not prevent oestrus from appearing at the normal time (i.e. approximately 42 days after the preceding oestrus). Mating occurred at the post-partum oestrus but lactation inhibited further oestrous cycles as well as delaying the development of the resultant uterine embryo. The period of delayed pregnancy can be as long as 4+ months. During most of this period the embryo remained free in the uterus as a dormant blastocyst, diameter 0.25-0.28 mm. Embryonic development was resumed during the weaning period when suckling was intermittent and diminishing or when the offspring was prematurely lost. Observations on both captive and wild populations suggested the existence of two breeding seasons, one in late winter and early spring, the other in summer. However, the evidence on which these breeding seasons are based is extremely limited. Reproduction in Potorous is compared with that in other marsupial species.

Vertical distribution of forms of potassium in major soil series of Tamil Nadu

2003 ◽  
Vol 51 (3) ◽  
pp. 339-346 ◽  
Author(s):  
S. Natarajan ◽  
A. Renukadevi
Keyword(s):  
Organic Carbon ◽  
Vertical Distribution ◽  
Tamil Nadu ◽  
Water Soluble ◽  
The Other ◽  
Soil Series ◽  
Exchangeable K ◽  
The Relationship ◽  
The Vertical Distribution ◽  
Total Potassium

Fifteen major soil series at the rate of three for each soil group, namely red non-calcareous, red calcareous, black calcareous, brown calcareous and alluvial soils, were studied for the vertical distribution of different forms of potassium. The total potassium content varied from 515-5513 ppm and generally increased with depth. It was positively related with clay, silt, CaCO3, CEC and total Ca. Non-exchangeable K ranged from 340-1326 ppm and did not exhibit any uniformity in its distribution in soil profiles. The exchangeable K varied from 45-684 ppm and was positively related to organic carbon. NH4OAc-K ranged from 15-298 ppm. Soil properties like clay, silt, CaCO3 and organic matter were positively related to available K. Water-soluble K varied from 2-33 ppm and was found to decrease with the depth of the soil profile. It was positively correlated with organic carbon and negatively related to clay plus silt. Studies on the relationship between the above forms of potassium indicate that, except for total K, the other forms were closely related, indicating the possibility of predicting one from the other.

Vertical distribution, seasonality and troposphericity of ice-supersaturated air masses in the northern mid-latitudes from regular in-situ observations by passenger aircraft

2020 ◽  
Author(s):  
Andreas Petzold ◽  
Susanne Rohs ◽  
Mihal Rütimann ◽  
Patrick Neis ◽  
Berkes Florian ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Vertical Distribution ◽  
North Atlantic ◽  
Observation Data ◽  
European Research ◽  
Air Masses ◽  
The North ◽  
The North Atlantic ◽  
Passenger Aircraft ◽  
The Vertical Distribution

<p>The vertical distribution and seasonal variation of water vapour volume mixing ratio (H<sub>2</sub>O VMR), relative humidity with respect to ice (RH<sub>ice</sub>) and particularly of regions with ice-supersaturated air masses (ISSR) in the extratropical upper troposphere and lowermost stratosphere are investigated at northern mid-latitudes over the regions Eastern North America, the North Atlantic and Europe for the period 1995 to 2010.</p><p>Observation data originate from regular and continuous long-term measurements of H<sub>2</sub>O VMR, temperature and RH<sub>ice</sub> by instrumented passenger aircraft in the framework of the European research program MOZAIC which is continued as European research infrastructure IAGOS (from 2011; see www.iagos.org). The observation data are analysed with respect to the thermal and dynamical tropopauses, as provided by ERA-Interim. Additionally, collocated O<sub>3</sub> observations from MOZAIC are used as tracer for stratospheric air masses.</p><p>Our key results provide in-depth insight into seasonal and regional variability and tropospheric nature of ice-supersaturated air masses at various distances from the tropopause layer. For the vertical distribution and seasonal variation of ISSR occurrence we show a comparison of our results to radio soundings and to satellite observations of cirrus cloud occurrence from AIRS and TOVs Path B instruments. Finally, for all three regions, we investigate the trends and the dependencies of ISSR occurrence on the North Atlantic Oscillation (NAO) index.</p>

Travelling disturbances in the ionosphere

1950 ◽  
Vol 202 (1069) ◽  
pp. 208-223 ◽  
Keyword(s):  
Seasonal Variation ◽  
Vertical Distribution ◽  
Sudden Change ◽  
Frequent Occurrence ◽  
Vertical Movements ◽  
Short Period ◽  
The Mean ◽  
The Vertical Distribution

Methods have been developed for the examination of the horizontal and vertical movements of short-period disturbances in the ionosphere. It has been found that quasi-periodic travelling disturbances with periods of from 10 to 60 min. are of frequent occurrence in the F region by day. They appear as temporary variations in the vertical distribution of ionization which show a horizontal progression and a vertical progression downwards. The horizontal directions of travel have a well-defined mean direction on most days. The mean direction shows a marked seasonal variation with a sudden change at each equinox. The horizontal rate of travel is usually between 5 and 10 km./min., and the rate of vertical progression downwards is approximately half the horizontal rate. The disturbances are considered to be variations of a compressional type in the atmosphere resulting in changes in the distribution of ionization.

scholarly journals Seasonal Dynamics of Taphrina deformans Inoculum in Peach Orchards

2007 ◽  
Vol 97 (3) ◽  
pp. 352-358 ◽  
Author(s):  
V. Rossi ◽  
M. Bolognesi ◽  
S. Giosuè
Keyword(s):  
Life Cycle ◽  
Relative Humidity ◽  
Early Spring ◽  
The Other ◽  
Late Winter ◽  
Parasitic Stage ◽  
Tree Canopies ◽  
Trap Plants ◽  
Second Period ◽  
Curled Leaves

The dynamics of the inoculum of Taphrina deformans were studied during a 4-year period by (i) inspecting curled leaves for the presence of asci, (ii) placing deposition spore samplers within the tree canopies, and (iii) exposing potted peach plants (trap plants). These three approaches produced consistent results. Four main periods characterized the dynamics of the inoculum: the first period coincides with the parasitic stage of the pathogen's life cycle and the other periods with the saprophytic stage. Mid- to late spring (first period) was characterized by the presence of asci on infected leaves which produced and ejected large quantities of ascospores in 96% of the samplings. Rainfall was not necessary for ascospore dispersal, which was favored by air temperature <20°C and relative humidity ≥80% or wetness duration >8 h. In summer and autumn (second period), blastospores were trapped in 54 and 24% of samplings, respectively, with low spore numbers. In the winter (third period), blasto-spores were trapped in the lowest numbers and in only 6% of samplings. In late winter to early spring (fourth period), blastospores were found in 56% of samples, with increasing numbers. Rainfall significantly influenced blastospore dispersal and temperature was correlated with the seasonality found during the saprophytic stage.

scholarly journals Assembly history modulates vertical root distribution in a grassland experiment

2021 ◽  
Author(s):  
Inés M. Alonso-Crespo ◽  
Emanuela W.A. Weidlich ◽  
Vicky M. Temperton ◽  
Benjamin M. Delory
Keyword(s):  
Vertical Distribution ◽  
Functional Groups ◽  
Plant Communities ◽  
Functional Group ◽  
Species Level ◽  
The Other ◽  
Priority Effects ◽  
Rooting Depth ◽  
Distribution Of Roots ◽  
The Vertical Distribution

The order of arrival of plant species during assembly can affect the structure and functioning of grassland communities. These so-called priority effects have been extensively studied aboveground, but we still do not know how they affect the vertical distribution of roots in the soil and the rooting depth of plant communities. To test this hypothesis, we manipulated the order of arrival of three plant functional groups (forbs, grasses and legumes) in a rhizobox experiment. Priority effects were created by sowing one functional group 10 days before the other two. Rhizoboxes in which all functional groups were sown simultaneously were used as controls. During the experiment, the mean rooting depth of plant communities was monitored using image analysis and a new methodological approach using deep learning (RootPainter) for root segmentation. At harvest, we measured aboveground (community and species level) and belowground (community level) biomass, and assessed the vertical distribution of the root biomass in different soil layers. At the community level, all scenarios where one functional group was sown before the other two had similar shoot and root productivity. At the species level, two forbs (Achillea millefolium and Centaurea jacea) benefited from arriving early, and one legume (Trifolium pratense) had a disadvantage when it was sown after the grasses. Priority effect treatments also affected the vertical distribution of roots. When grasses were sown first, plant communities rooted more shallowly than when forbs or legumes were sown first,. In addition, roots moved down the soil profile 24% more slowly in grasses-first communities. Our results highlight that plant functional group order of arrival in grassland communities can affect the vertical distribution of roots in the soil and this may have implications for species coexistence.

Coping with darkness and low temperatures: foraging strategies in Steller's eiders, Polysticta stelleri, wintering at high latitudes

2001 ◽  
Vol 79 (3) ◽  
pp. 402-406 ◽  
Author(s):  
Geir Helge Systad ◽  
Jan Ove Bustnes
Keyword(s):  
Low Temperatures ◽  
Early Spring ◽  
The Other ◽  
Foraging Strategies ◽  
Winter Period ◽  
Late Winter ◽  
Feeding Time ◽  
High Latitudes ◽  
Late Autumn ◽  
Polysticta Stelleri

To examine how Steller's eiders, Polysticta stelleri, wintering at 70°N cope with adverse winter conditions in terms of darkness and low temperatures, we studied their feeding behaviour during four periods between late autumn and early spring. Steller's eiders were most likely to feed during daylight and twilight, but they also fed during darkness. The incidence of feeding was highest at low tide, and there was a significant interaction between tidal cycle and winter period. Hence, the birds fed more intensively at low tide in midwinter (January) than during the other periods. Air temperatures were between 8 and 10°C lower in midwinter than during the other periods, and during this period the eiders also fed more by means of nondiving techniques (up-ending, surface feeding). The total estimated feeding time was highest in late autumn and midwinter (5.9 and 6.3 h were spent actively feeding, respectively) and lower in late winter and spring (5.1 and 4.6 h, respectively). Thus, as energy requirements increased as a result of low temperatures, Steller's eiders increased their feeding effort, but also reduced feeding costs by reducing diving depth. The results of this study suggest that the Steller's eider is behaviourally well adapted to survive winter at high latitudes at relatively low stress.

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