scholarly journals Annual and seasonal variation in the food supply harvestable by knot Calidris canutus staging in the Wadden Sea in late summer

1992 ◽  
Vol 83 ◽  
pp. 129-139 ◽  
Author(s):  
L Zwarts ◽  
A-M Blomert ◽  
JH Wanink
Keyword(s):  
Seasonal Variation ◽  
Food Supply ◽  
Wadden Sea ◽  
Late Summer ◽  
Calidris Canutus

scholarly journals Contrasting recruitment seasonality of sea urchin species in Gran Canaria, Canary Islands (eastern Atlantic)

2014 ◽  
Vol 15 (3) ◽  
pp. 475 ◽  
Author(s):  
S. GARCIA-SANZ ◽  
P. G. NAVARRO ◽  
F. TUYA
Keyword(s):  
Community Structure ◽  
Seasonal Variation ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Late Summer ◽  
Paracentrotus Lividus ◽  
Abundant Species ◽  
Late Winter ◽  
Gran Canaria ◽  
Arbacia Lixula

Despite sea-urchins can play an important role affecting the community structure of subtidal bottoms, factors controlling the dynamics of sea-urchin populations are still poorly understood. We assessed the seasonal variation in recruitment of three sea-urchin species (Diadema africanum, Paracentrotus lividus and Arbacia lixula) at Gran Canaria Island (eastern Atlantic) via monthly deployment of artificial collectors throughout an entire annual cycle on each of four adjacent habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds) within a shallow coastal landscape. Paracentrotus lividus and A. lixula had exclusively one main recruitment peak in late winter-spring. Diadema africanum recruitment was also seasonal, but recruits appeared in late summer-autumn, particularly on ‘urchin-grazed’ barrens with large abundances of adult conspecifics. In conclusion, this study has demonstrated non-overlapping seasonal recruitment patterns of the less abundant species (P. lividus and A. lixula) with the most conspicuous species (D. africanum) in the study area.

scholarly journals Seasonal Patterns of Carbohydrates in Mandarin cvs. ‘Fremont’, ‘Nova’ and ‘Robinson’ on Different Rootstocks

2013 ◽  
Vol 41 (1) ◽  
pp. 255 ◽  
Author(s):  
Ercan YILDIZ ◽  
Mustafa KAPLANKIRAN ◽  
Turan Hakan DEMIRKESER ◽  
Celil TOPLU
Keyword(s):  
Seasonal Variation ◽  
Starch Content ◽  
Late Summer ◽  
Carbohydrate Content ◽  
Poncirus Trifoliata ◽  
Soluble Carbohydrate ◽  
Total Carbohydrate ◽  
Fertilization Program ◽  
Total Carbohydrate Content ◽  
Continuous Decrease

The study was conducted at the experimental farm of Mustafa Kemal University, Dörtyol, Turkey during the 2010 and 2011 growing seasons. The aim of this study was to investigate the effect of ‘Troyer’ and ‘Carrizo’ citranges (Poncirus trifoliata Raf. × Citrus sinensis Osb. var. ‘Troyer’ and ‘Carrizo’), and common sour orange (Citrus aurantium L. var. common), rootstocks on the seasonal variation of carbohydrate content in the leaves of cvs. ‘Fremont’, ‘Nova’, and ‘Robinson’ mandarin. The seasonal variation of carbohydrate content of the three cultivars budded on different rootstocks was nearly same. Soluble carbohydrate concentration showed a continuous decrease from January to mid or late-summer, and then slowly began to increase after early autumn till winter. The sucrose was the dominant soluble carbohydrate in leaves. The seasonal evolution of starch content in leaves increased initially during January to March, and then decreased in April. The starch concentration showed a continuous decrease slowly until the mid-autumn, and then accumulation began during late-autumn and winter. The total carbohydrate content differences among the rootstocks were significant, but the content was changed among the cultivars and according to the season. The change in the total carbohydrate content of leaf tissues showed a strong similarity in cultivars budded on different rootstocks throughout the year. The total carbohydrate content reached their lowest levels in July for cv. ‘Robinson’, in August for cv. ‘Fremont’ and cv. ‘Nova’. The total carbohydrate content in leaves increased from the mid- or late-summer to winter. It is suggested that the seasonal variation of carbohydrate content in plant tissues can be considered during fertilization program in mandarin trees.

A Chart-recording Weighing Machine for Beekeeping or other Research

1927 ◽  
Vol 18 (1) ◽  
pp. 63-65
Author(s):  
C. B. Williams
Keyword(s):  
Seasonal Variation ◽  
Late Summer ◽  
Chart Recording

In the course of the beekeeping work of this Department we have had a number of hives weighed at regular intervals of about a week by means of a steelyard and tripod, and two permanently standing on platform weighing machine and weighed every day. The information obtained from these has been of great value in showing the seasonal variation in activity, the periods of honey flow, and the effect on the hives of the presence of enormous numbers of hornets in the late summer.There were, however, many problems, such as the daily periods of activity and honey-collecting, the effect of high midday temperature, etc., that could only be dealt with by more frequent weighings, and it was felt that a machine to record continuously the weight of the hive by means of a rotating clock drum and pen would be a most valuable instrument of research.

Movements of Australian flying foxes (Pteropodidae: Megachiroptera).

1965 ◽  
Vol 13 (1) ◽  
pp. 53 ◽  
Author(s):  
JE Nelson
Keyword(s):  
Food Supply ◽  
Late Summer ◽  
Early Summer ◽  
Summer Camps ◽  
Surrounding Area ◽  
Flying Foxes ◽  
Coastal Species ◽  
Pteropus Poliocephalus ◽  
Immature Form

Evidence is presented to show that the coastal species Pteropus poliocephalus and P. gouldi congregate in large camps from early until late summer. In these large summer camps the young are born and raised, the sexes become associated, and conception occurs. The numbers within these camps are influenced by the availability of blossom in the surrounding area. The adults are normally dispersed during the winter while the immature form winter camps. These camps contain a larger percentage of adults in those winters in which blossom is more abundant. The inland species P. scapulatus forms large camps in early summer but the young are born in autumn when the population is dispersed. Since the food supply of P. scapulatus is less dependable and undergoes greater fluctuations than that of the coastal species, P. scapulatus is more nomadic than P. poliocephalus and P. gouldi.

scholarly journals The seasonal cycle of ice-nucleating particles linked to the abundance of biogenic aerosol in boreal forests

2020 ◽  
Author(s):  
Julia Schneider ◽  
Kristina Höhler ◽  
Paavo Heikkilä ◽  
Jorma Keskinen ◽  
Barbara Bertozzi ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Boreal Forest ◽  
Seasonal Cycle ◽  
Weather Forecasting ◽  
Late Summer ◽  
Active Surface ◽  
Ambient Air ◽  
Ice Nucleation ◽  
Forest Environment ◽  
New Findings

Abstract. Ice-nucleating particles (INPs) trigger the formation of cloud ice crystals in the atmosphere. Therefore, they strongly influence cloud microphysical and optical properties, as well as precipitation and the life cycle of clouds. Improving weather forecasting and climate projection requires an appropriate formulation of atmospheric INP concentrations. This remains challenging, as the global INP distribution and variability depend on a variety of aerosol types and sources, and neither their short-term variability nor their long-term seasonal cycles are well covered by continuous measurements. Here, we provide the first year-long set of observations with a pronounced INP seasonal cycle in a boreal forest environment. Besides the observed seasonal cycle in INP concentrations with a minimum in wintertime and maxima in early and late summer, we also provide indications for a seasonal variation in the prevalent INP type. We show that the seasonal dependency of INP concentrations and prevalent INP types is most likely driven by the abundance of biogenic aerosol. As current parameterizations do not reproduce this variability, we suggest a new parameterization approach, which considers the seasonal variation of INP concentrations. For this, we use the ambient air temperature as a proxy for the season which affects the source strength of biogenic emissions and by that the INP abundance over the boreal forest areas. Furthermore, we provide new INP parameterizations based on the Ice Nucleation Active Surface Site (INAS) approach, which specifically describes the ice nucleation activity of boreal aerosols particles prevalent in different seasons. Our results characterize the boreal forest as an important but variable INP source and provide new perspectives to describe these new findings in atmospheric models.

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