scholarly journals Water column and bed-sediment core samples collected from Brownlee Reservoir near Oxbow, Oregon, 2012

Data Series ◽  
10.3133/ds809 ◽  
2013 ◽  
Author(s):  
Ryan L. Fosness ◽  
Jesse Naymik ◽  
Candice B. Hopkins ◽  
John F. DeWild
Keyword(s):  
Water Column ◽  
Sediment Core ◽  
Bed Sediment ◽  
Core Samples ◽  
Brownlee Reservoir

Pesticides and heavy metals in sediment core samples from a coastal area in Japan

2017 ◽  
Vol 51 (6) ◽  
pp. 525-536
Author(s):  
Chikumbusko Chiziwa Kaonga ◽  
Kazuhiko Takeda ◽  
Hiroshi Sakugawa ◽  
Hideo Yamazaki
Keyword(s):  
Heavy Metals ◽  
Sediment Core ◽  
Coastal Area ◽  
Core Samples

Field evaluation of plaster-based temephos pellets for residual control of midge larvae (Diptera: Chironomidae) in establishing rice crops

1994 ◽  
Vol 34 (5) ◽  
pp. 659 ◽  
Author(s):  
MM Stevens ◽  
GN Warren
Keyword(s):  
Water Column ◽  
Water Samples ◽  
Field Evaluation ◽  
Application Rate ◽  
Control Agent ◽  
Fourth Instar ◽  
Soil Core ◽  
Potential Control ◽  
Core Samples ◽  
Application Rates

A pelletised formulation of temephos (5% a.i.) was evaluated as a potential control agent for chironomid midge larvae in establishing rice crops. Four application rates between 0.03 and 0.53 mg a.i./L (42-732 g a.i./ha) were applied to 80 m2 experimental rice bays immediately after flooding. Water samples and soil core samples were taken at regular intervals until 29 days post-treatment. Larvae were extracted from core samples using magnesium sulfate (MgSO4) flotation, whilst laboratory-reared fourth instar Chironomus tepperi Skuse larvae were used in bioassays with field-collected water samples to determine pesticide activity in the water column. All treatments significantly suppressed C. tepperi-type larvae in the field for at least 13 days. Some suppression of non-C. tepperi-type larvae was obtained at 0.27 mg a.i./L, whilst at 0.53 mg a.i./L all chironomids were reduced to negligible levels for the full period of the trial. In bioassays, significant levels of water column toxicity to fourth instar C. tepperi larvae were only recorded for 2 days after treatment at the highest application rate. Our results indicate that plaster-based temephos pellets have the potential to provide effective, single application control of chironomid larvae in establishing rice crops without the risk of spray drift inherent in the aerial application of liquid insecticides.

scholarly journals Distribution of Natural Radioactivity,137Cs,90Sr, and Plutonium Isotopes in a Water Column and Sediment Core along the Algerian Coast

2007 ◽  
Vol 2007 ◽  
pp. 1-6 ◽  
Author(s):  
A. Noureddine ◽  
M. Benkrid ◽  
R. Maoui ◽  
M. Menacer ◽  
R. Boudjenoun
Keyword(s):  
Water Column ◽  
Sediment Core ◽  
Sediment Cores ◽  
Dry Weight ◽  
Artificial Radioactivity ◽  
Energy Agency ◽  
Area Of Interest ◽  
Algerian Coast ◽  
Seawater Samples ◽  
Thorium Series

Concentrations of natural (40K,210Pb, uranium, and thorium series) and artificial radioelements (137Cs,90Sr,239+240Pu) were determined in seawater and sediment samples collected from stations along the Algerian coast. Seawater was collected from the surface to a maximum depth of 2000 m; the sediment cores were sampled from a depth of around 1500 m. This work was carried out in August 2001, in the framework of the Regional African project /7/004 (RAF), by the accomplishment of an oceanographic campaign organized by the International Atomic Energy Agency (IAEA) in collaboration with Commissariat à l'Energie Atomique (COMENA) and L'Institut des Sciences de la Mer et de L'Amenagement du Littoral (ISMAL), on board of the research vessel of M.S. Benyahia of ISMAL. In addition to the record of the conductivity (mS) and temperature (°C) data at each station, seawater samples were treated and preconcentrated on board, those of sediment cores were divided into different layers in order to undergo analyses in the laboratory of radiological impact studies of Algiers. Concentration results were obtained for137Cs and90Sr in mBq/L and239+240Pu inμBq/L in seawater, and also for natural and artificial radionuclides in Bq/kg dry weight in the layers of the sediment cores. The different profiles of137Cs,239+240Pu,90Sr, and210Pb concentrations against depth were presented to show artificial radioactivity distribution in the water column and sediment core. Concentrations of137Cs in the sediment core were also used to identify the137Cs peak in the area of interest.

scholarly journals Cold Active Amylases Producing Psychrotolerants Isolated from Nella Lake, Antarctica

2018 ◽  
Vol 15 (1) ◽  
pp. 05-16
Author(s):  
Abhas Kumar Maharana ◽  
Shiv Mohan Singh
Keyword(s):  
Sediment Core ◽  
Yeast Extract ◽  
Submerged Fermentation ◽  
Soluble Starch ◽  
East Antarctica ◽  
Core Samples ◽  
Larsemann Hills ◽  
Amylase Production ◽  
Cold Active ◽  
Food And Beverage

Cold active amylase was investigated by bacteria and yeast isolates from the sediment core samples of Nella Lake,Larsemann Hills region, East Antarctica. Between potential yeast and bacteria isolates screened for amylases, best isolates were identified asRhodotorula sp. Y-37 and ArthrobacteralpinusN16 by molecular technique.Amylase production capabilities of both the isolate subjected for optimization processes by using submerged fermentation technique with soluble starch as substrate.The results indicate that a supplement of 1% w/v glucose, 1% w/v yeast extract and 0.1% w/v KCl at pH 7.0with 5% v/v inoculum enhances the amylase production by 5.72-fold using Rhodotorula sp. Y-37. In other hands, the activators are 1% w/v of galactose and peptone, 0.1% w/v KCl and 2.5% v/v inoculum at pH 7.0 enhances the amylase production by 3.74-fold using ArthrobacteralpinusN16. Cold-active amylasecan be used in detergent, textile, food and beverage industries. Bio-degradation of starchy materials by cold active amylases can contribute in cleaning of environment at cold regions without harming the climate.

NUTRIENT DYNAMICS IN EELGRASS (ZOSTERA MARINA) MEADOW AND THE VARIATION OF NUTRIENT CONTENTS OF EELGRASS

2017 ◽  
Author(s):  
Toshimasa Asahi ◽  
Toshimasa Asahi ◽  
Kazuhiko Ichimi ◽  
Kazuhiko Ichimi ◽  
Kuninao Tada ◽  
...  
Keyword(s):  
Water Column ◽  
Pore Water ◽  
Sediment Core ◽  
Zostera Marina ◽  
Nutrient Dynamics ◽  
Similar Rate ◽  
Nutrient Concentrations ◽  
Nutrient Source ◽  
Nutrient Contents ◽  
Seagrass Biomass

Nutrient dynamics in seagrass beds and nutrient demands of seagrass biomass are not clear, although nutrient uptake of seagrass has been experimentally studied in the laboratory. We conducted the field observations and the bottom sediment core incubations to estimate nutrient fluxes in the seagrass, Zostera marina meadow. DIN (nitrate, nitrite and ammonium) concentrations were always low particularly during the Z. marina growing season (from spring to summer), and water exchanges caused by tidal currents hardly supplied nutrient demand for Z. marina. Sediment pore water also supplied insufficient nutrients to Z. marina, because pore water had less volume than the water column, although DIN concentrations of pore water were 10-100 fold higher than those of the water column. Nutrient flux from sediment to water column estimated by the sediment core incubation experiments showed a similar rate with tidal water exchange. Thus, our results suggested that Z. marina adapted for low nutrient concentrations and each nutrient source in the Z. marina meadow slightly contributed but could not support Z. marina growth. We found that another nutrient source, for example, precipitation, supplied high DIN to the Z. marina meadow. After rainfall, the DIN concentration of seawater in the Z. marina meadow increased 2-5 times higher. Moreover, nitrogen content of eelgrass also increased 2-3 times higher during several days. Those results suggested that Z. marina was usually exposed to a low nutrient concentration but could uptake abundant nutrients from temporary nutrient supplies such as precipitation.

Sign in / Sign up

Export Citation Format

Share Document