scholarly journals Effects of Temperature, Salinity, pH, and Light on Filtering and Grazing Rates of a Calanoid Copepod (Schmackeria dubia)

2008 ◽  
Vol 8 ◽  
pp. 1219-1227 ◽  
Author(s):  
Changling Li ◽  
Xiaoxia Luo ◽  
Xianghu Huang ◽  
Binhe Gu
Keyword(s):  
Light Intensity ◽  
Calanoid Copepod ◽  
Food Sources ◽  
Calanoid Copepods ◽  
Low Light ◽  
Marine Food Web ◽  
Larval Fishes ◽  
Trophic Links ◽  
Marine Food ◽  
Effects Of Temperature

Calanoid copepods are key components of the marine food web and the food sources of many larval fishes and planktivores, and grazers of phytoplankton. Understanding the ranges of major environmental variables suitable for their growth is essential to maintain the balance between trophic links and resources protection. In this study, the effects of temperature, salinity, pH, and light intensity on the filtering and grazing rates of a herbivorous copepod (Schmackeria dubia) were conducted in several control experiments. Our results indicated that experimental animals grazed normally at water temperatures between 15 and 35°C. The filtering and grazing rates increased by onefold at water temperatures from 15 to 25°C, with a peak at around 30°C.S. dubiafed normally at salinity ranging from 20 to 30 ppt, with significantly low filtering and grazing rates at salinity below 15 ppt and above 35 ppt. The filtering and grazing rates increased as pH increased, peaked at approximately 8.5, and then decreased substantially. Light intensity also displayed an important impact on the filtering and grazing rates. Filtering and grazing rates were high when light intensity was greater than 20 and less than 200 µmol m-2s-1. S. dubia nearly stopped feeding at low light intensity (less than 20 µmol m-2s-1).

scholarly journals Nestedness of trophic links and biological traits in a marine food web

Ecosphere ◽  
2015 ◽  
Vol 6 (9) ◽  
pp. art161 ◽  
Author(s):  
M. C. Nordström ◽  
K. Aarnio ◽  
A. Törnroos ◽  
E. Bonsdorff
Keyword(s):  
Food Web ◽  
Biological Traits ◽  
Marine Food Web ◽  
Trophic Links ◽  
Marine Food

Some Effects of Temperature and Light on Floral Initiation and Development in Acacia pycnantha

1985 ◽  
Vol 12 (2) ◽  
pp. 109 ◽  
Author(s):  
M Sedgley
Keyword(s):  
Light Intensity ◽  
Floral Development ◽  
Early Stage ◽  
The Other ◽  
Floral Initiation ◽  
Ambient Conditions ◽  
Low Light ◽  
Floral Primordia ◽  
Effects Of Temperature ◽  
Normal Light

Floral initiation and development in Acacia pycnantha were studied under three environments. Two had ambient southern Australian temperatures of warm summer (mean max. 32°C, mean min. 16°C) and cool winter (mean max. 19°C, mean min. 8°C), one with full sunlight (outside) and the other with 30% light intensity (shadehouse). The other environment (glasshouse) had slightly lower than normal light intensity and a relatively constant year round temperature of mean 28°C maximum and 16°C minimum. Plants were scored for microscopic and macroscopic evidence of floral initiation and development. Floral primordia were initiated all year round under all environments. Floral development proceeded normally under ambient conditions of temperature and light, and anthesis occurred between August and October. Under low light intensity, floral development did not progress beyond a very early stage and macroscopically visible racemes were rare. Under the constant temperatures, floral development proceeded normally up to the stage of microsporogenesis and megasporogenesis. Meiosis did not occur and inflorescence buds ceased growth and were shed from the plant. Plants were transferred between the outside and glasshouse conditions in June, at around the stage of meiosis. Those transferred from outside to the glasshouse did not flower whereas some of those transferred from the glasshouse to outside flowered, but later and for a shorter period than plants maintained outside throughout. It appears that a 70% reduction in sunlight inhibits floral development at an early stage and that temperatures of approximately mean maximum 19°C and minimum 8°C are required for meiosis in Acacia pycnantha.

EFFECTS OF TEMPERATURE AND LIGHT INTENSITY ON NOCTURNAL ACTIVITY PATTERNS OF THE NORTHERN JUNE BEETLE, PHYLLOPHAGA FUSCA, AND THE COMMON JUNE BEETLE, P. ANXIA (COLEOPTERA: SCARABAEIDAE)

1982 ◽  
Vol 114 (12) ◽  
pp. 1151-1157 ◽  
Author(s):  
J. C. Guppy
Keyword(s):  
Light Intensity ◽  
Soil Temperature ◽  
Activity Patterns ◽  
Degree Days ◽  
Low Light ◽  
Flight Season ◽  
The Common ◽  
Effects Of Temperature ◽  
High Soil Temperature ◽  
Oviposition Sites

AbstractIn western Quebec, first flight of overwintered adults of the northern June beetle, Phyllophaga fusca (Froelich), and the common June beetle, P. anxia (Le Conte), occurred in mid-May with the accumulation of about 156 degree-days above 5 °C beginning 1 April. When soil temperature was 10 °C or higher, flight started 12–45 min after sunset, apparently in response to an endogenous rhythm that was triggered by low light intensity within the range 1.0 to 96.9 lux; high soil temperature induced early flight. Early in the flight season, duration of flight was 10–46 min and was inversely related to time of flight initiation. In early June, the flight began in darkness and was associated with peak oviposition and ageing; it lasted 20–35 min and was directed into the trees or to oviposition sites within a field.Males were attracted to light during a pre-copulatory flight which lasted more than 1 h until maximum coupling occurred near 2230 h; beetles remained in copula for 3 h or more. Morning flight directly back to the soil was triggered by light intensity increasing to about 1.0 lux.

scholarly journals Temperature dependence of Arctic zooplankton metabolism and excretion stoichiometry

2012 ◽  
Vol 9 (6) ◽  
pp. 7443-7463
Author(s):  
M. Alcaraz ◽  
R. Almeda ◽  
E. Saiz ◽  
A. Calbet ◽  
C. M. Duarte ◽  
...  
Keyword(s):  
Inorganic N ◽  
Nutrient Pool ◽  
Marine Food Web ◽  
Qualitative And Quantitative ◽  
Metabolic Products ◽  
Natural Temperature ◽  
Marine Food ◽  
Effects Of Temperature ◽  
The Relationship

Abstract. We assessed the relationship between zooplankton metabolism (respiration and inorganic N and P excretion) and "in situ" temperature through a grid of stations representing a range of natural temperature variation during the ATOS-Arctic cruise (July 2007). The objective was to explore not only the direct effects of temperature on O2 consumption and NH4-N and PO4-P excretion, but also to investigate the possible relationships between temperature and the stoichiometry of the metabolic products. Zooplankton metabolic rates increased according to the rising temperature conditions, following the Arrhenius equation. However, the activation energy differed for the various metabolic processes considered. Respiration was the metabolic activity less affected by temperature, followed by NH4-N and PO4-P excretion, and as a consequence the values of the C : N, C : P and N : P quotients of the metabolic products were inversely related to temperature. The effects of temperature on the stoichiometry of the excretion products would contribute to modify the nutrient pool available for phytoplankton and induce qualitative and quantitative shifts in the characteristics of primary producers that could possibly translate into the whole Arctic marine food web.

Pendugaan Parameter Genetik Kedelai Generasi F4 pada Intensitas Cahaya Rendah

Agrotek ◽  
2018 ◽  
Vol 2 (3) ◽  
Author(s):  
Yohanis Amos Mustamu ◽  
Trikoesoemaningtyas Trikoesoemaningtyas ◽  
Desta Wirnas ◽  
Didy Sopandie ◽  
Darman M. Arsyad
Keyword(s):  
Light Intensity ◽  
Genetic Parameter ◽  
Design Experiment ◽  
Low Light ◽  
Experimental Field ◽  
High Heritability ◽  
Intensity Condition ◽  
Augmented Design ◽  
Genetic Coefficient ◽  
The University

The objective of this study was to collect information on genetic parameter and agronomy character of soybean F4 generation in the low light intensity condition. The parameter was tested to 130 lines F4 which are produced by Balai Besar Pengkajian dan Pengembangan Teknologi Pertanian (BBP2TP) Boor and the genotype of Sibayak, Tegal, Tanggamus, and Argomulyo were used as controls. The experiment was conducted in the university�s experimental field in Cikabayan, from September to December 2007. A total of 130 advance (F4) soybean lines were evaluated under shading in an augmented design experiment. The result of this study showed that all character has low genetic coefficient. The weight character of 25 grains has a considerably high heritability number in low li

scholarly journals Complexities of disturbance response in a marine food web

2021 ◽  
Author(s):  
Kristy A. Lewis ◽  
Robert R. Christian ◽  
Charles W. Martin ◽  
Kira L. Allen ◽  
Ashley M. McDonald ◽  
...  
Keyword(s):  
Food Web ◽  
Marine Food Web ◽  
Disturbance Response ◽  
Marine Food

scholarly journals Growth of Haematococcus pluvialis on a Small-Scale Angled Porous Substrate Photobioreactor for Green Stage Biomass

2021 ◽  
Vol 11 (4) ◽  
pp. 1788
Author(s):  
Thanh-Tri Do ◽  
Binh-Nguyen Ong ◽  
Tuan-Loc Le ◽  
Thanh-Cong Nguyen ◽  
Bich-Huy Tran-Thi ◽  
...  
Keyword(s):  
Light Intensity ◽  
Algal Biomass ◽  
Haematococcus Pluvialis ◽  
Biomass Productivity ◽  
Pilot Scale ◽  
Small Scale ◽  
Porous Substrate ◽  
Low Light ◽  
Green Algal ◽  
Green Stage

In the production of astaxanthin from Haematococcus pluvialis, the process of growing algal biomass in the vegetative green stage is an indispensable step in both suspended and immobilized cultivations. The green algal biomass is usually cultured in a suspension under a low light intensity. However, for astaxanthin accumulation, the microalgae need to be centrifuged and transferred to a new medium or culture system, a significant difficulty when upscaling astaxanthin production. In this research, a small-scale angled twin-layer porous substrate photobioreactor (TL-PSBR) was used to cultivate green stage biomass of H. pluvialis. Under low light intensities of 20–80 µmol photons m−2·s−1, algae in the biofilm consisted exclusively of non-motile vegetative cells (green palmella cells) after ten days of culturing. The optimal initial biomass density was 6.5 g·m−2, and the dry biomass productivity at a light intensity of 80 µmol photons m−2·s−1 was 6.5 g·m−2·d−1. The green stage biomass of H. pluvialis created in this small-scale angled TL-PSBR can be easily harvested and directly used as the source of material for the inoculation of a pilot-scale TL-PSBR for the production of astaxanthin.

Transfer of photosynthetically fixed carbon between the prokaryotic green alga Prochloron and its ascidian host

1983 ◽  
Vol 34 (3) ◽  
pp. 431 ◽  
Author(s):  
DJ Griffiths ◽  
L Thinh
Keyword(s):  
Light Intensity ◽  
Green Alga ◽  
Host Tissue ◽  
Total Carbon ◽  
Symbiotic Association ◽  
Fixed Carbon ◽  
Low Light ◽  
Ascidian Species ◽  
Dark Fixation ◽  
Efficient Transfer

In the symbiotic association between the prokaryotic green alga Prochloron and three didemnid host species (Diplosoma similis, Lissoclinum bistratum, Trididemnum cyclops), between 6 and 51 % of the total carbon fixed during exposure for 1 h to H14CO3- in the light (150 �E m-2 s-1) becomes associated with the host tissue. Dark fixation of 14CO2 in these ascidian species and in Lissoclinum punctatum never exceeds 6% of photosynthetic fixation at saturating light intensity. The corresponding values for dark fixation of 14CO2 in isolated Prochloron cells fall within the same range. There is very little excretion of photosynthate from whole colonies of the above ascidian species nor from Didemnum molle, Lissoclinum voeltzkowi and Trididemnum miniatum (usually less than 1 % of total photosynthate at saturation light intensity), suggesting an efficient transfer mechanism from Prochloron to host. Evidence from pulse-chase experiments suggests that transfer probably involves the early products of photosynthesis. The extent of transfer of photosynthate between Prochloron and T. cyclops varies with the rate of photosynthetic 14CO2 fixation into the whole colony but there is some transfer even at low light intensities, which strongly limit photosynthesis.

The Role of Ammonites in the Mesozoic Marine Food Web Revealed by Jaw Preservation

Science ◽  
2011 ◽  
Vol 331 (6013) ◽  
pp. 70-72 ◽  
Author(s):  
I. Kruta ◽  
N. Landman ◽  
I. Rouget ◽  
F. Cecca ◽  
P. Tafforeau
Keyword(s):  
Food Web ◽  
Marine Food Web ◽  
Marine Food
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