A Study of the Diatoms of the Ouse Estuary, Sussex III. The Seasonal Variation in the Littoral Epiphyte Flora and the Shore Plankton

1964 ◽  
Vol 44 (3) ◽  
pp. 613-644 ◽  
Author(s):  
J. T. Hopkins
Keyword(s):  
Littoral Zone ◽  
Sea Water ◽  
Limiting Factors ◽  
Diatom Species ◽  
Growth Phases ◽  
Lethal Temperatures ◽  
Planktonic Diatom ◽  
Coastal Sea ◽  
Temperature Records ◽  
The Relationship

SUMMARYAnalyses have been made of some of the constituents of the coastal sea water and the river water, and the results have been correlated with the growth phases of some planktonic diatom species and littoral epiphytes, although for most species the sea-water temperature and light intensity were limiting factors.The factor determining the death of an epiphytic diatom community in the littoral zone has been considered to be the air temperature in conjunction with desiccation and a summary of the limiting temperatures for each of the four substrata is given in Table 7. Table 10 is a summary of all the distribution and temperature records. The heat itself is not lethal in many cases but the desiccation of the epiphyte in the littoral zone is accelerated at higher temperatures. Diatoms in damp situations were found to occur at temperatures which in a dry site were limiting, and further work indicating the relationship between relative humidity and lethal temperatures is needed.The ability of a diatom to survive depends upon the water-retaining ability of the substratum. Chalk and large algae favoured the growth of most solitary epiphytes, and filamentous epiphytes grew particularly well on algae except the filamentous Navicula, which were best suited by chalk. The Achnanthes blue-green community was most frequent on wood. Concrete makes a firm substratum and allows rapid growth in winter but it is easily dried and most diatoms on it are destroyed in the summer.Four diatom genera (Fragilaria, Grammatophora, Biddulphia and Melosira) are able to exist in the epiphyte flora and the shore plankton and the term facultative epiphyte is suggested to describe the behaviour of at least some of the species of these genera.

THE VALUE OF STANDARD WEATHER DATA IN YIELD–CLIMATE STUDIES OF TWO OAT VARIETIES

1966 ◽  
Vol 46 (1) ◽  
pp. 27-34 ◽  
Author(s):  
P. Dermine ◽  
H. R. Klinck
Keyword(s):  
Correlation Coefficients ◽  
Limiting Factors ◽  
Weather Data ◽  
Growth Phases ◽  
Eastern Canada ◽  
Temperature And Precipitation ◽  
Temperature Records ◽  
Precipitation Records ◽  
Relationship Of ◽  
Climate Studies

Temperature and precipitation records during various growth phases of oats were studied in relation to the yields of two varieties, Ajax and Roxton, collected at five locations in Eastern Canada, over the 1940–1956 period.Available temperature records consisted of mean maximum, mean minimum, and mean temperature range, taken in standard shelters at 4 ft above ground. Simple correlation coefficients between oat yields and the weather records were small and seldom significant. No marked improvement in correlation sensitivity was gained by separating mean daily temperature into its two components, mean maximum and minimum temperature, nor by considering weather records in relation to given growth phases of the crop. The two oat varieties belonging to opposite maturity ranges, produced correlations of similar signs with the weather data. The relative position of one variety to the other did not display any consistent or significant correlation with the weather data.On the basis of these results, standard weather records were shown to be inadequate to measure the true climate–yield relationship of a widely adapted crop such as oats, in a climate where temperature and precipitation are seldom limiting factors per se.

SITE-SPECIFIC EQUATIONS OF STATE FOR COASTAL SEA AREAS AND INLAND WATER BODIES

2017 ◽  
Author(s):  
Natalia Andrulionis ◽  
Natalia Andrulionis ◽  
Ivan Zavialov ◽  
Ivan Zavialov ◽  
Elena Kovaleva ◽  
...  
Keyword(s):  
Equation Of State ◽  
Black Sea ◽  
Water Samples ◽  
Equations Of State ◽  
Sea Water ◽  
Ionic Composition ◽  
Water Bodies ◽  
Aral Sea ◽  
The Black Sea ◽  
Coastal Sea

This article presents a new method of laboratory density determination and construction equations of state for marine waters with various ionic compositions and salinities was developed. The validation of the method was performed using the Ocean Standard Seawater and the UNESCO thermodynamic equation of state (EOS-80). Density measurements of water samples from the Aral Sea, the Black Sea and the Issyk-Kul Lake were performed using a high-precision laboratory density meter. The obtained results were compared with the density values calculated for the considered water samples by the EOS-80 equation. It was shown that difference in ionic composition between Standard Seawater and the considered water bodies results in significant inaccuracies in determination of water density using the EOS-80 equation. Basing on the laboratory measurements of density under various salinity and temperature values we constructed a new equation of state for the Aral Sea and the Black Sea water samples and estimated errors for their coefficients.

MEASUREMENTS OF PRIMARY PRODUCTION IN COASTAL SEA WATER USING A LARGE-VOLUME PLASTIC SPHERE

1961 ◽  
Vol 6 (3) ◽  
pp. 237-258 ◽  
Author(s):  
C. D. McAllister ◽  
T. R. Parsons ◽  
K. Stephens ◽  
J. D. H. Strickland
Keyword(s):  
Primary Production ◽  
Large Volume ◽  
Sea Water ◽  
Coastal Sea ◽  
Plastic Sphere

scholarly journals Peculiarly pleasant weather for US maize

2018 ◽  
Vol 115 (47) ◽  
pp. 11935-11940 ◽  
Author(s):  
Ethan E. Butler ◽  
Nathaniel D. Mueller ◽  
Peter Huybers
Keyword(s):  
Climate Change ◽  
Growing Season ◽  
Crop Model ◽  
World Population ◽  
Growth Phases ◽  
Climate Trends ◽  
Historical Trends ◽  
Yield Trends ◽  
The Relationship ◽  
Temperature Responses

Continuation of historical trends in crop yield are critical to meeting the demands of a growing and more affluent world population. Climate change may compromise our ability to meet these demands, but estimates vary widely, highlighting the importance of understanding historical interactions between yield and climate trends. The relationship between temperature and yield is nuanced, involving differential yield outcomes to warm (9−29 °C) and hot (>29 °C) temperatures and differing sensitivity across growth phases. Here, we use a crop model that resolves temperature responses according to magnitude and growth phase to show that US maize has benefited from weather shifts since 1981. Improvements are related to lengthening of the growing season and cooling of the hottest temperatures. Furthermore, current farmer cropping schedules are more beneficial in the climate of the last decade than they would have been in earlier decades, indicating statistically significant adaptation to a changing climate of 13 kg·ha−1· decade−1. All together, the better weather experienced by US maize accounts for 28% of the yield trends since 1981. Sustaining positive trends in yield depends on whether improvements in agricultural climate continue and the degree to which farmers adapt to future climates.

scholarly journals Agroecological Determinants of Potato Spatiotemporal Yield Variation at the Landscape Level in the Central and Northern Ukraine

2021 ◽  
Vol 4 (2) ◽  
pp. 34-47
Author(s):  
Anastasiia Zymaroieva ◽  
Tetiana Fedoniuk ◽  
Svitlana Matkovska ◽  
Olena Andreieva ◽  
Victor Pazych
Keyword(s):  
Crop Yields ◽  
Climatic Factors ◽  
High Sensitivity ◽  
Potato Yield ◽  
Limiting Factors ◽  
Forest Steppe ◽  
Yield Parameters ◽  
Bioclimatic Variables ◽  
Potato Yields ◽  
The Relationship

Global food security largely depends on the crop yield increase, so the study of the yield-limiting factors of potato (the second bread) is a pressing issue today. This study determines the contribution of the agroecological factors, namely, bioclimatic variables, soil indicators, and factors of landscape diversity, to the variation in potato yields. Conducted in Polissya and Forest-steppe zones of Ukraine during 1991–2017, this study has not only addressed the relationship between ecological determinants and potato yields, but also considered crop yields as a dynamic system. The dynamics of potato yields from the mid-1990s to the present is described by a log-logistic model. There are statistically significant regression dependencies between potato yield parameters and agroecological factors. Potato yield is dependent on the diversity of landscape cover. The relationship between yield parameters and landscape-ecological diversity is non-linear, which determines the presence of optimal landscape structure for the highest potato yields. Among climatic factors, the continental climate is of the greatest importance for potato yield. The high sensitivity of potato yield parameters to soil indices was found, and mostly the soil texture components (silt content), which largely determines the potato yield spatial variation.

scholarly journals COASTAL SEA SURFACE TEMPERATURE RECORDS ALONG THE BAJA CALIFORNIA PENINSULA

2012 ◽  
Vol 27 (2) ◽  
pp. 65
Author(s):  
M. T. Sicard -González ◽  
M. A. Tripp -Valdéz ◽  
L. Ocampo ◽  
A. N. Maeda -Martínez ◽  
S. E. Lluch -Cota
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Baja California ◽  
Sea Surface ◽  
Baja California Peninsula ◽  
Coastal Sea ◽  
Temperature Records

Registros costeros de temperatura superficial del mar en la Península de Baja California El análisis de series ambientales de temperatura de alta resolución temporal en las zonas costeras permitirá caracterizar mejor las formas y escalas de variación. Las bases de datos disponibles actualmente carecen de suficiente resolución para detectar variaciones ambientales a escalas de horas y días. En este trabajo damos a conocer una colección de registros de alta frecuencia de diversos sitios a lo largo de las costas de la Península de Baja California. Hasta el momento se tienen 47 sitios; sin embargo, esta red de monitoreo pretende expandirse con el objetivo de generar bases de datos de acceso público y gratuito, proporcionando una valiosa herramienta no solo para la investigación, sino también para aplicaciones como la producción acuícola.

The accumulation of 137Cs by brackish water invertebrates and its relation to the regulation of potassium and sodium

1963 ◽  
Vol 43 (2) ◽  
pp. 541-565 ◽  
Author(s):  
G. W. Bryan
Keyword(s):  
New Media ◽  
Brackish Water ◽  
Sea Water ◽  
Indirect Evidence ◽  
The Body ◽  
Limiting Factor ◽  
Wide Range ◽  
Concentration Factors ◽  
The Relationship ◽  
Potamopyrgus Jenkinsi

The relationship between the ability of brackish water invertebrates to regulate Na and K and the extent to which the radioactive fission product 137Cs can be accumulated has been studied.The brackish water isopod Sphaeroma hookeri and the gastropod Potamopyrgus jenkinsi have been acclimatised to a wide range of sea-water dilutions. Unfed Sphaeroma can survive in sea-water concentrations of 100–2·5%, while Potamopyrgus can live fairly indefinitely in concentrations of 50–0·1%. Measurements of Na and K in the whole animals of both species and in the blood of Sphaeroma have been made. Salt movements are quite rapid and acclimatization to new media is achieved by both species in less than 10 h. Concentration factors for inactive K in particular increase to high values in the more dilute media.Uptake of the isotopes 42K and 137Cs from solution has been examined in both species over a range of sea-water concentrations. All of the body K is exchangeable with 42K and in Sphaeroma exchange of 42K between the blood and tissues is so rapid that the body surface appears to be the limiting factor in the uptake of the isotope. Both species exchange 42K more rapidly in the higher concentrations of sea water and one reason for this may be the existence of an exchange diffusion component of exchange which increases as the salinity of the medium is raised. Indirect evidence suggests that the excretion of 42K in urine is probably not an important factor in exchange.

Detection of PAHs in coastal sea water using portable SERS sensor

2019 ◽  
Vol 48 (3) ◽  
pp. 322003
Author(s):  
严 霞 Yan Xia ◽  
贾文杰 Jia Wenjie ◽  
史晓凤 Shi Xiaofeng ◽  
张 旭 Zhang Xu ◽  
张艺超 Zhang Yichao ◽  
...  
Keyword(s):  
Sea Water ◽  
Coastal Sea

scholarly journals Prescribed Burning as A Management Tool to Destroy Dry Seeds of Invasive Conifers in Heathland in Denmark

Land ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 432
Author(s):  
Christian Andreasen ◽  
Kasper Rossing ◽  
Christian Ritz
Keyword(s):  
High Temperature ◽  
Prescribed Burning ◽  
Germination Rate ◽  
Management Tool ◽  
Fuel Load ◽  
The Mean ◽  
Temperature Records ◽  
Conifer Trees ◽  
The Relationship ◽  
Practical Constraints

Non-indigenous conifers are considered invasive to the coastal dune heathland in Denmark, and massive clearing is carried out in an attempt to recreate and keep the original heathland. Burning is a common method for managing, but its feasibility to control the seed bank of conifers has not been investigated. This project shows that the burning of logged conifer trees will often eliminate seeds of lodgepole pine, mugo pine and Sitka spruce, even when the seeds were placed into a depth of five centimeters in the soil. The effect on seeds depends on the fuel load and the fire conditions (e.g., dryness, wind, and temperature). If the seeds were exposed to a high temperature, the seeds were not able to germinate afterward. The temperature was about 80 °C for all species. If the sum of temperatures based on temperature records every 30 s exceeded between 12,000 and 14,000 °C no seeds were able to germinate. The relationship between the mean temperature of the burns and the germination rate at seeds placed in various soil depths was modelled. Findings should be interpreted cautiously as each depth-species combinations were not replicated in space or time due to practical constraints.

Breathing Movements in Entobdella Soleae (Trematoda, Monogenea) from the Skin of the Common Sole

1962 ◽  
Vol 42 (1) ◽  
pp. 93-104 ◽  
Author(s):  
G. C. Kearn
Keyword(s):  
Oxygen Content ◽  
Sea Water ◽  
The Body ◽  
Scyliorhinus Canicula ◽  
Solea Solea ◽  
Flat Fish ◽  
The Common ◽  
The Relationship ◽  
Common Sole

An undulating movement of the body was observed in Entobdella soleae, a monogenean found on the blind surface of a mud-dwelling flat-fish, Solea solea, at Plymouth. The movement is described and shown to have a breathing function, the rate of undulation increasing with decreasing oxygen content of the ambient sea water and vice versa.The relationship between the movement and micro-habitat is discussed and the phenomenon is compared with breathing movements in other muddwelling animals.A similar movement was noted in three other skin-parasitic monogeneans: Acanthocotyle sp. from Raia clavata, Pseudocotyle squatinae from Squatina squatina and Leptocotyle minor from Scyliorhinus canicula.

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