scholarly journals Plankton studies in a mangrove environment: IV. size fractionation of the phytoplankton

1967 ◽  
Vol 16 (1) ◽  
pp. 39-42 ◽  
Author(s):  
C. Teixeira ◽  
J. Tundisi ◽  
J. Santoro
Keyword(s):  
Seasonal Variation ◽  
Size Range ◽  
Size Fractionation ◽  
Mangrove Swamp ◽  
Mangrove Environment ◽  
Back Ground ◽  
One Year

The seasonal variation of the different fractions of photosynthesizing phytoplankton, measured by C-14 uptake, was studied in a mangrove swamp region, at 25º south latitude. The data showed that the fraction with size range from 5 µ, to 65 µ, was responsible for an average of 61.80% of C-14 uptake of the phytoplankton, during one year, samples having been taken every other month, and showed little seasonal variation when compared with the fraction larger than 65 µ. The results presented here, confirmed general conclusions of other authors, and provided a back-ground for future investigation in the area.

scholarly journals Plankton studies in a mangrove environment: VII. size fractionation of the phytoplankton: some studies on methods

1968 ◽  
Vol 17 (1) ◽  
pp. 89-94 ◽  
Author(s):  
J. Tundisi ◽  
C. Teixeira
Keyword(s):  
Particulate Matter ◽  
Incubation Period ◽  
Size Fractionation ◽  
Mangrove Swamp ◽  
Size Fractions ◽  
Mangrove Environment ◽  
Inshore Waters ◽  
Series Of Experiments ◽  
C14 Method ◽  
Relative Uptake

A series of experiments on the different methods of measuring the relative uptake of C14, by the various size fractions of the phytoplankton, were carried out in a mangrove swamp of the estuarine type at 25º south latitude. As a complement, some factors which might influence the relative uptake of the different fractions in inshore waters, were studied. These factors are related, mainly, with the increase on the amount of labelled particulate matter during incubation period, the effect of different pressures in the filtration of the size fractions of the phytoplankton, the use of a range of volumes for the incubation of samples, and the effect of formalin on the fixation of samples, after the incubation period. Based on these results, some suggestions are made for the use of the C14 method in inshore waters.

Biennial Reproductive Cycle of Blue King Crab, Paralithodes platypus, at the Pribilof Island, Alaska and Comparison to a Congener, P. camtschatica

1989 ◽  
Vol 46 (6) ◽  
pp. 932-940 ◽  
Author(s):  
Gregory C. Jensen ◽  
David A. Armstrong
Keyword(s):  
Carapace Length ◽  
Reproductive Output ◽  
Size Range ◽  
Egg Mass ◽  
King Crab ◽  
Pribilof Island ◽  
Blue King Crab ◽  
Paralithodes Platypus ◽  
One Year ◽  
Reproductive Events

Pribilof Island blue king crab (BKC; Paralithodes platypus) were sampled by beam trawl in May and August of 1983 and April 1984 to determine timing of reproductive events. Biennial reproduction was found to be the result of slow ovarian growth in large, muciparous females, while smaller primiparous females are often able to spawn in two consecutive years. Mating and egg extrusion occur in late March to early May and eggs hatch in mid-April of the following year, consequently, the embryonic period and rate of development is approximately 12 mo, similar to that of its congener the red king crab (RKC; P. camtschatica). Comparison of the reproductive output of the two species revealed that despite the 2 yr ovarian cycle, BKC only produce 20–30% more dry egg mass at any carapace length than do RKC, a substantially smaller difference than previously calculated. One year after molt, females of both species are not significantly different in dry body weight over a size range of 100–140 mm carapace length, but RKC have produced about three times more dry ovarian weight than BKC of comparable size, suggesting that biennial reproduction in BKC may be the result of energetic limitations.

scholarly journals Assessment of EGNOS Tropospheric Correction Model

2001 ◽  
Vol 54 (1) ◽  
pp. 37-55 ◽  
Author(s):  
Nigel Penna ◽  
Alan Dodson ◽  
Wu Chen
Keyword(s):  
Seasonal Variation ◽  
Elevation Angle ◽  
Weather Conditions ◽  
Tropospheric Delay ◽  
Spatially Correlated ◽  
Positioning Errors ◽  
Subsequent Effect ◽  
Weather Changes ◽  
One Year ◽  
Tropospheric Delays

Within the implementation of the European Geo-stationary Navigation Overlay System (EGNOS), a significant residual error in positioning is due to tropospheric delay effects. The EGNOS guidelines recommend that tropospheric delay is modelled using an empirical correction algorithm based on a receiver's height and estimates of meteorological parameters developed from average and seasonal variation data. However, such a simple average and seasonal variation model is unlikely to emulate temporal weather changes exactly. The potential errors involved in the application of the recommended algorithm and the consequent effects on the positioning errors, under typical UK weather conditions, are detailed in this paper. This was achieved by comparing tropospheric delays produced by the EGNOS model, with tropospheric delays estimated from high precision carrier phase GPS, over a one-year period for five UK stations. The RMS EGNOS model zenith tropospheric delay errors ranged from 4·0 to 4·7 cm, with maximum errors ranging from 13·2 to 17·8 cm. The errors were also shown to be spatially correlated. The subsequent effect on position error is shown to be dependent on the satellite elevation cut-off angle adopted and on whether or not the observations are weighted according to the satellite elevation angle.

Characterization of aquatic colloids by a combination of LIBD and ICP-MS following the size fractionation

2002 ◽  
Vol 90 (9-11) ◽  
Author(s):  
M. Bouby ◽  
T. Ngo Manh ◽  
Horst Geckeis ◽  
Franz J. Scherbaum ◽  
Jae-Il Kim
Keyword(s):  
Heavy Metal ◽  
Metal Ion ◽  
Size Range ◽  
Uv Spectroscopy ◽  
Relative Number ◽  
Size Exclusion ◽  
Size Fractionation ◽  
Size Change ◽  
Icp Ms ◽  
Inorganic Components

SummaryHumic colloids in deep groundwater are characterized in order to ascertain how heavy metal ions of chemical homologue to actinides are associated in different size fractions. The colloid size fractionation is made by two different methods: flow field flow fractionation (FFFF) and size exclusion chromatography (SEC), which is followed by analysis of chemical composition using UV spectroscopy for organic components and ICP-MS for inorganic components. Relative number density of humic colloids following the size fractionation is determined by laser-induced breakdown detection (LIBD). For the appraisal of colloid size change upon metal ion complexation, purified Aldrich humic acid is loaded with the EuWhereas the organic component of humic colloids is found in the size range about 3 nm, the inorganic components of actinides homologues, M(III) and M(IV), are observed in the fractionated size range from 10 nm to 35 nm. This observation leads us to presume that the inorganic composites, composed of heavy metal elements, are peptised by humic/fulvic acid. The laboratory traced elements,

scholarly journals Comparison of mercury concentrations measured at several sites in the Southern Hemisphere

2014 ◽  
Vol 14 (22) ◽  
pp. 30611-30637 ◽  
Author(s):  
F. Slemr ◽  
H. Angot ◽  
A. Dommergue ◽  
O. Magand ◽  
M. Barret ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Southern Hemisphere ◽  
Research Station ◽  
Annual Average ◽  
Austral Spring ◽  
Monthly Average ◽  
Intermittent Measurements ◽  
One Year ◽  
Cape Grim ◽  
Mercury Monitoring

Abstract. Our knowledge of the distribution of mercury concentrations in air of the Southern Hemisphere was until recently based mostly on intermittent measurements made during ship cruises. In the last few years continuous mercury monitoring has commenced at several sites in the Southern Hemisphere providing new and more refined information. In this paper we compare mercury measurements at several sites in the Southern Hemisphere made over a period of at least one year at each location. Averages of monthly medians show similar although small seasonal variations at both Cape Point and Amsterdam Island. A pronounced seasonal variation at Troll Research Station in Antarctica is due to frequent mercury depletion events in the austral spring. Due to large scatter and large standard deviations of monthly average median mercury concentrations at Cape Grim no systematic seasonal variation could be found there. Nevertheless, the annual average mercury concentrations at all sites during the 2007–2013 period varied only between 0.85 and 1.05 ng m−3. Part of this variability is likely due to systematic measurement uncertainties which we propose can be further reduced by improved calibration procedures. We conclude that mercury is much more uniformly distributed throughout the Southern Hemisphere than the distributions suggested by measurements made onboard ships. This finding implies (a) that trends observed at one or a few sites in the Southern Hemisphere are likely to be representative for the whole hemisphere, and (b) that smaller trends can be detected in shorter time periods. We also report a change of the trend sign at Cape Point from decreasing mercury concentrations in 1996–2004 to increasing concentrations since 2007.

scholarly journals Some ecological aspects of free-living Haemaphysalis juxtakochi Cooley, 1946 (Acari: Ixodidae) in Panama

2014 ◽  
pp. 3984-3989 ◽  
Author(s):  
Gleydis García G ◽  
Angélica Castro DF ◽  
Sergio Bermúdez C ◽  
Santiago Nava
Keyword(s):  
Seasonal Variation ◽  
Comparative Analysis ◽  
Seasonal Distribution ◽  
Test Results ◽  
Major Peak ◽  
Free Living ◽  
Wooded Area ◽  
Ecological Aspects ◽  
Significant Difference ◽  
One Year

ABSTRACTObjective. To describe the seasonal variation and perform a comparative analysis on habitat preference of Haemaphysalis juxtakochi in Panama. Materials and methods. Ticks were collected from the vegetation, using a white cloth, between January 2009 and March 2010, in four site located in Summit Municipal Park (SMP), two in wooded area (WA) and two in grasslands (GR).The ticks were determined as larvae, nymphs and adults of H. juxtakochi. The number of ticks collected in each area was employed to describe the seasonal distribution of both immature and adult stages, and the non-parametric Mann-Whitney U test. Results. A total of 2.338 ticks in WA and 560 ticks in GR were collected. The major peak of adults from May to July, nymphs peaked from January to April and the peak of larvae abundance from December and January. There was a significant difference in the number of ticks collected in the two areas for each tick stage (larvae, mean number (MN) in WA 120.14, MN in GR 57.07, P: 0.02; nymphs, MN in WA 46.42, MN in GR 16.38, P: 0.018; adults, MN in WA 6.64, MN in GR 1.78, P: 0.02). Conclusions. The results suggest that H. juxtakochi maintains a one-year cycle in the study areas. This cycle would be characterized by the immature population peaks in the dry season; while adults are distributed throughout year, with a peak in the transition from the rainy and dry. Moreover, H. juxtakochi was more abundant in forests than in grasslands, which could lead to a better adaptation to forested conditions.

scholarly journals Seasonal variation of the dominant allergenic fungal aerosols – One year study from southern Indian region

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Hema Priyamvada ◽  
Raj Kamal Singh ◽  
M. Akila ◽  
R. Ravikrishna ◽  
Rama Shanker Verma ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Indian Region ◽  
One Year

Historical Overview of Oil Spills from All Sources (1960–1998)

1999 ◽  
Vol 1999 (1) ◽  
pp. 1097-1102 ◽  
Author(s):  
Dagmar Schmidt Etkin
Keyword(s):  
Oil Spill ◽  
Media Coverage ◽  
Poster Session ◽  
Oil Spills ◽  
Size Range ◽  
Historical Overview ◽  
Storage Tanks ◽  
One Year ◽  
Annual Amount

ABSTRACT This poster session gives an overview of oil spill statistics on oil spills of at least 10,000 gallons (34 tonnes) that have occurred worldwide over the last 20 years. Included are: the annual amount of oil spilled from different source types as well as in total, and the number and amount of oil spilled by size range. The data indicate that in any one year, the total amount of oil spilled depends largely on the incidence of catastrophic spills. While the frequency of smaller spills under 100,000 gallons (340 tonnes) greatly exceeds those of spills of over 1 million gallons (3,400 tonnes), the total volume of these smaller spills represents only a fraction of one catastrophic spill. While tanker spills have often gotten more media coverage, the amount of oil spilled from these vessels is often less than that spilled from pipelines, storage tanks, and other facilities.

Seasonal variation of vitamin D and bone metabolism among premenopausal strict vegans and omnivores in finland over a period of one year

1996 ◽  
Vol 6 (S1) ◽  
pp. 151-151
Author(s):  
T Outila ◽  
R Seppänen ◽  
M Kärkkäinen ◽  
C Lamberg-Allardt
Keyword(s):  
Vitamin D ◽  
Seasonal Variation ◽  
Bone Metabolism ◽  
One Year

scholarly journals Intercomparison of air ion spectrometers: a basis for data interpretation

2011 ◽  
Vol 4 (1) ◽  
pp. 1139-1180 ◽  
Author(s):  
S. Gagné ◽  
K. Lehtipalo ◽  
H. E. Manninen ◽  
T. Nieminen ◽  
S. Schobesberger ◽  
...  
Keyword(s):  
Simultaneous Measurement ◽  
Size Range ◽  
Field Measurements ◽  
Ambient Air ◽  
Data Interpretation ◽  
Particle Formation ◽  
New Particle Formation ◽  
Neutral Cluster ◽  
One Year ◽  
First Time

Abstract. We evaluated 11 air ion spectrometers from Airel Ltd. after they had spent one year in field measurements as a part of the EUCAARI project: 5 Air Ion Spectrometers (AIS), 5 Neutral cluster and Air Ion Spectrometers (NAIS) and one Airborne NAIS (ANAIS). This is the first time that an ANAIS is evaluated and compared so extensively. The ion spectrometers' mobility and concentration accuracy was evaluated. Their measurements of ambient air were compared between themselves and to reference instruments: a DMPS, a BSMA, and an Ion-DMPS. We report on the simultaneous measurement of a new particle formation (NPF) event by all 11 instruments and the 3 reference instruments. To our knowledge, it is the first time that the size distribution of ions and particles is measured by so many ion spectrometers during a NPF event. The new particle formation rates (~ 0.2 cm−3 s−1 for ions and ~ 2 cm−3 s−1 for particles) and growth rates (~ 25 nm h−1 in the 3–7 nm size range) were calculated for all the instruments. The NAISs and the ANAIS gave higher concentrations and formation rates than the AISs. The latter agreed better with reference instruments. Finally, based on the results presented here, we give guidelines for data interpretation, when data from different ion spectrometers are compared.

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