Production of Chironomus, Procladius, and Chaoborus at Different Levels of Phytoplankton Biomass in Lake Memphremagog, Quebec–Vermont

1977 ◽  
Vol 34 (11) ◽  
pp. 2001-2007 ◽  
Author(s):  
R. M. Dermott ◽  
J. Kalff ◽  
W. C. Leggett ◽  
J. Spence
Keyword(s):  
Phytoplankton Biomass ◽  
Standing Stock ◽  
Dry Weight ◽  
Annual Production ◽  
The South ◽  
Algal Production ◽  
The North ◽  
Chaoborus Punctipennis ◽  
The Mean ◽  
Different Levels

In Lake Memphremagog a north–south gradient in algal production and biomass exists during the ice-free period, with highest production in the southern areas. In response, the mean annual benthic standing stock (dry weight) in the south basin was 2.8 times greater than in the north basin at comparable depth. Mean annual standing stock of Procladius denticulatus and Chironomus anthracinus were significantly (5.8 and 3.1 times, respectively) higher in the south, while that of Chaoborus punctipennus did not differ significantly between areas. Annual production of P. denticulatus was greater in the south (0.861 g/m2) than in the north (0.143 g/m2). Similarly for Chironomus anthracinus annual production was greater in the south (3.393 g/m2) than in the north (1.264 g/m2). Production of Chaoborus punctipennis was greater in the north (0.066 g/m2) than in the south (0.348 g/m2). P:B ratios were less variable. Key words: Lake Memphremagog, benthos, production, nutrient gradient, mortality

Presence and Quantification of Microplastic in Urban Tap-Water

2020 ◽  
Author(s):  
Claudia B. Pratesi ◽  
Maria Aparecida A.L. Santos Almeida ◽  
Geysa S. Cutrim Paz ◽  
Marcelo H. Ramos Teotonio ◽  
Felipe Mendes dos Santos Cardia ◽  
...  
Keyword(s):  
Tap Water ◽  
The South ◽  
Plastic Pollution ◽  
Wing Area ◽  
Health Crisis ◽  
Toxicological Effect ◽  
The North ◽  
Study Results ◽  
The Mean ◽  
Number Of Particles

Abstract Background: Plastic pollution is a rapidly growing environmental and human health crisis, with no sign of improvement. Since 2012 the number of studies on plastic pollution has quadrupled, and macro to nano-size plastics have been documented even in the planet's remote biomes. Studies have shown contamination by microplastics (MPs) in various types of food consumed by humans, including seafood, honey, sugar, salt, tap-water and bottled water and beer. The study's objective was to detect the possible contamination by MPs in drinking water samples collected from the two main residential and commercial areas of Brasília.Methods: A total of 32 samples of tap water were collected, 16 samples in the south zone, and 16 samples in the north zone of the city (respectively, South Wing and North Wing). Samples were processed and transferred to the Sedgewick-Rafter counting cell chamber. The presence of MPs particles was analyzed using a Nikon Eclipse fluorescence microscope.Results: MPs were found in 100% of the samples. The mean MPs per 500 ml found in the South Wing area was 97, while the mean number of particles in the North Wing area was 219.Conclusion: The study results reveal a disturbing amount of MP particles in Brasilia's tap-water. This surprising number of particles in tap-water is especially concerning considering that tap-water is not the only source of MPs to which people are exposed. The cumulative and toxicological effect of this chronic exposure is alarming.

scholarly journals Explaining Cultural Capital through Combining Different Dimensions of Social Capital: A Fussy Analysis Based on Artificial Neural Network Approach (ANNFIS) (A Case Study of Citizens Aged 18 and Above in Tehran)

2016 ◽  
Vol 3 (2) ◽  
pp. 46
Author(s):  
Ghorbanali Ebrahimi ◽  
Hadi Razeghimaleh
Keyword(s):  
Neural Network ◽  
Social Capital ◽  
Artificial Neural Network ◽  
Cultural Capital ◽  
Multivariate Linear Regression Analysis ◽  
The South ◽  
The North ◽  
The Mean ◽  
Artificial Neural ◽  
North And South

<p>The main objective of this study was to find out whether social capital and its dimensions affect the cultural capital of citizens in Tehran, and whether there is any difference in the social capital and cultural capital in the north and south urban neighborhoods. To answer these questions, a fuzzy questionnaire for collecting the data was designed. The research method in this study was based on Artificial Neural Network -Fuzzy Inference System (ANNFIS). Statistical population included individuals aged 18 and above residing in Tehran, and sample size consisted of 2538 people.</p><p>The findings of this study indicated that there is a significant difference in the cultural capital between north and south neighborhoods in Tehran. The mean of cultural capital in the south neighborhoods (2.49 out of 10) was higher than that of north neighborhoods (6.77 out of 10). Furthermore, the degree of neighborhood social capital was different between the north and south neighborhoods of Tehran, and this difference was statistically significant, so that the mean of social capital in the south neighborhoods (6.75 out of 10) was greater than that of north neighborhoods (2.88 out of 10).</p>Multivariate linear regression analysis to explain cultural capital has revealed that social trust (- 0.502) and relation networks (- 0.087) exerted the highest and lowest impact on the dependent variable, respectively. It should be noted that, of the three variables entered into the regression equation, all variables have remained in the equation. It should be noted that the effects of all variables on the dependent variable of cultural capital was negative.

scholarly journals Seasonal and interannual (ENSO) climate variabilities and trends in the South China Sea over the last three decades

2018 ◽  
Author(s):  
Violaine Piton ◽  
Thierry Delcroix
Keyword(s):  
South China Sea ◽  
El Niño ◽  
El Nino ◽  
The South ◽  
The North ◽  
Meridional Winds ◽  
El Niño Events ◽  
The Mean ◽  
Increasing Trends ◽  
El Nino Events

Abstract. We present a short overview of the long-term mean and variability of five Essential Climate Variables observed in the South China Sea over the last 3 decades, including sea surface temperature (SST), sea level anomaly (SLA), precipitation (P), surface wind and water discharge (WD) from the Mekong and Red Rivers. At the seasonal time scale, SST and SLAs increase in the summer (up to 4.2 °C and 14 cm, respectively), and P increases in the north. The summer zonal and meridional winds reverse and intensify (mostly over the ocean), and the WD shows positive anomalies. At the interannual time scale, each variable appears to be correlated with El Niño Southern Oscillation (ENSO) indices. Eastern Pacific El Niño events produce basin-wide SST warming (up to 1.4 °C) with a 6-month lag. The SLAs fall basin-wide (by up to 9 cm) during an El Niño event (all types), with a 3-month lag. The zonal and meridional winds strengthen (up to 4 m/s) in the north (weaken in the south) during all types of El Niño events, with a 3–5-month lag. A rainfall deficit of approximately 30 % of the mean occurs during all types of El Niño phases. The Mekong River WD is reduced by 1/3 of the mean 7–8 months after all types of El Niño events. We also show increasing trends of SST as high as 0.24 °C/decade and SLAs by 41 mm/decade. Increasing trends are observed for zonal wind, which is possibly linked to the phase of the Pacific Decadal Oscillation, and decreasing trends are observed for P in the north and both WD stations that were analyzed. The likely driving mechanisms and some of the relationships between all observed anomalies are discussed

Cycle de développement, croissance et production de Pisidium amnicum (Mollusca: Bivalvia) dans le Saint-Laurent (Québec)

1981 ◽  
Vol 59 (12) ◽  
pp. 2350-2359 ◽  
Author(s):  
B. Vincent ◽  
G. Vaillancourt ◽  
N. Lafontaine
Keyword(s):  
Population Dynamics ◽  
Sexual Maturity ◽  
Dry Weight ◽  
Mortality Rates ◽  
The Other ◽  
Annual Production ◽  
Bithynia Tentaculata ◽  
The Mean ◽  
Total Dry Weight ◽  
St Lawrence River

The population dynamics of Pisidium amnicum have been studied in one population of the St. Lawrence River over a 2-year period during which 19 samples were taken. The species can live up to 3 years and it is iteroparous; individuals generally attain sexual maturity after 1 year and they reproduce twice, once at 2 and once at 3 years of age. In adults, mortality is lower in winter than during the rest of the year and mortality rates are twice as high during the 1st year than during the 2nd year. Total dry weight (PT, in milligrams) is related to maximum length (L, in millimetres) according to the equation PT = 0.0283∙L3,80 and flesh dry weight (PC, in milligrams) is related to length as follows: PC = 0.007∙L3,18. The annual production to mean biomass (P/B) ratio is 1.4, the mean annual production being 1.298 mg/m2 of total dry weight and 107 mg/m2 of flesh weight. Comparing these results with those obtained for the gastropod Bithynia tentaculata in the same environment and at the same period of the year has shown that the growth of Pisidium amnicum is far less influenced by the temperature regime than that of the other species and that its production is at least 10 times lower.

Phytoplankton Succession and Primary Production in Babine Lake, British Columbia

1975 ◽  
Vol 32 (12) ◽  
pp. 2413-2427 ◽  
Author(s):  
John G. Stockner ◽  
K. R. S. Shortreed
Keyword(s):  
Primary Production ◽  
Sockeye Salmon ◽  
Mixed Layer Depth ◽  
Carbon Assimilation ◽  
Annual Production ◽  
Phosphate Limitation ◽  
The South ◽  
South Basin ◽  
The North ◽  
Principal Factors

Ten stations located in six zones (subbasins) were sampled biweekly from May to October 1973 to detect possible regional differences in production in this large, 155 km long, dystrophic lake. The spring bloom occurred in all zones while a fall bloom occurred only in Zones 5 and 6. Carbon assimilation showed two peaks in south basin zones, but only one (spring) at zones north of Topley Landing. Seasonal variation in phytoplankton numbers and volume, seston, and chlorophyll a followed a pattern similar to that noted for primary production. Mean production was 100 mg C∙m−2∙day−1 in Zones 1–4, but was 145 in Zones 5 and 6. Annual production was estimated at 25 g C∙m−2 in the north basin and 40 in the south basin. Reasons for the regional disparities are discussed, with greatest significance given to regional variations in mixed layer depth, surface inflows (loading), and basin mean depth. The development and sustainment of the autumnal bloom of Tabellaria fenestrata is thought to be one of the principal factors responsible for greater production in the south basin.An estimated 0.05 g TP∙m−2 enters the lake yearly. This can vary depending on the return of adult sockeye salmon (Oncorhynchus nerka), whose carcasses contribute up to 20% of the total. An estimated 30% is lost via the Babine River, and it is speculated that of the remaining 70%, most is lost to the sediments. Phosphate limitation is implied as a chief factor limiting primary production in the north basin stations, but not in the south basin. On the basis of total phosphorus load the lake is classed as oligotrophic, but in terms of annual production and its humic stained waters it is more correctly considered mixotrophic.

The Prehistoric Landscape of Dartmoor Part 2: North and East Dartmoor

1983 ◽  
Vol 49 (1) ◽  
pp. 195-241 ◽  
Author(s):  
Andrew Fleming
Keyword(s):  
Bronze Age ◽  
Major Axis ◽  
Regional Level ◽  
The South ◽  
Field System ◽  
The North ◽  
History Of ◽  
Single Block ◽  
Upland Pasture ◽  
Different Levels

This paper describes the distribution of reaves (Bronze Age land boundaries) on North and East Dartmoor (cf. Fleming 1978a for South Dartmoor). It is suggested that they form a pattern which reflects the territorial arrangements of several communities distributed around the edge of Dartmoor. Each of these territories tended to be about 3–4 km in breadth and to include a single block of enclosed land laid out on one axis, sometimes covering over 1000 ha. The scale of territories here is more independent of the incidence of major geographical features than is the case on South Dartmoor. There is normally a simple division between enclosed land and upland pasture, without the intermediate settled valley zones which are important on the South Moor. Classic parallel reave systems occur, but so do simpler ‘block systems’, and this variability can best be conceptualized as a continuum, within a broad tradition of laying out enclosed land on a major axis and in rectangular parcels. It is suggested, mainly on the basis of the interdependence of the pattern's components, that most boundaries on Dartmoor were laid out in response to a single decision taken around 1300 bc (1700/1600 BC), although some cross-ridge reaves may be earlier in date. Some details of the layout reflect different levels of social organisation — what are here termed the neighbourhood group, the community, and the regional level of organisation. The paper also discusses the settlement history of different regions of Dartmoor, suggesting that a third major upland common, the East Moor, should be considered equivalent to the North Moor and the South Moor in terms of the development of land use. The East Moor was eventually encroached upon by the Rippon Tor parallel reave system, probably the largest prehistoric field system known in Britain.

GOITROUS ENZOOTIC IN THE WILD RAT WITH A GEOGRAPHICAL DISTRIBUTION SIMILAR TO ENDEMIC HUMAN GOITRE

1971 ◽  
Vol 66 (2) ◽  
pp. 193-200 ◽  
Author(s):  
S. Orts ◽  
P. Dustin ◽  
F. Delange
Keyword(s):  
Geographical Distribution ◽  
Iodine Deficiency ◽  
The South ◽  
The North ◽  
South West ◽  
Lake Kivu ◽  
Wild Rat ◽  
In The Wild ◽  
Wild Rats ◽  
The Mean

ABSTRACT The aim of the present work has been to verify the determining influence of the environmental factor on the geographical distribution of goitre in Idjwi Island (Lake Kivu, Dem. Rep. of the Congo). The weight and histology of the thyroid of wild rats have been compared in the areas of high (North Idjwi) and low (South West Idjwi) prevalence of goitre in man. This animal has been chosen because its food consists mainly of the remains of human food and because it abounds in the two areas investigated. The mean thyroid weight in 114 rats captured in the North of the Island is 18.3 ± 0.5 mg. This result is significantly higher than the value of 12.1 ± 0.3 mg obtained in 101 animals captured in the South West of the Island (P < 0.001). Furthermore, an aspect of hyperstimulation characterized by a reduction or disappearance of the colloid of the thyroid vesicles was observed in 66.7% of the glands in the first area, as compared to 8.5% only in those of the second area (P < 0.0005). This investigation thus shows the existence of a goitrous enzootic in the wild rat in Idjwi Island, which is geographically superimposable on the endemic human goitre. Since the North and the South West of the Island have a similar iodine deficiency, the present data support the hypothesis of the existence in the North of the Island of an additional goitrogenic factor, distinct from the iodine deficiency.

ECOPHYSIOLOGICAL EFFECTS OF OIL SPILLS FROM AMOCO CADIZ ON PELAGIC COMMUNITIES—PRELIMINARY RESULTS

1979 ◽  
Vol 1979 (1) ◽  
pp. 175-185
Author(s):  
J. F. Samain ◽  
J. Moal ◽  
J. Y. Daniel ◽  
J. Boucher ◽  
J. Lefevre
Keyword(s):  
Oil Spills ◽  
Dry Weight ◽  
Mean Value ◽  
Soluble Proteins ◽  
Faunal Composition ◽  
Preliminary Results ◽  
The North ◽  
First Results ◽  
The Mean ◽  
Pelagic Communities

ABSTRACT First results on distribution and changes of biomass (dry weight and total soluble proteins), physiology (amylase, trypsin) and faunal composition of zooplankton are reported for the two months following the Amoco Cadiz spill on the northern Brittany coast. A shortage of biomass in the A ber area is attributed to hydrocarbons. The low level of the mean value of biomass on the north coasts, and the peculiarities at the estuarine station on Lannion Bay and the Trieux area are reported and discussed.

scholarly journals Spatiotemporal Changes of Reference Evapotranspiration in Mongolia during 1980–2006

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Wenjun Yu ◽  
Tonghua Wu ◽  
Weizhen Wang ◽  
Ren Li ◽  
Tianye Wang ◽  
...  
Keyword(s):  
Hydrological Cycle ◽  
Reference Evapotranspiration ◽  
Kendall Test ◽  
Climatic Conditions ◽  
Meteorological Variables ◽  
The South ◽  
Sparse Vegetation ◽  
The North ◽  
The Mean ◽  
Aridity Indices

Reference evapotranspiration (RET) plays an important role in the terrestrial hydrological cycle. Applying the Penman-Monteith method, the RET over Mongolia was estimated from 1980 to 2006. The changing trends and magnitude of RET were detected by the Mann-Kendall test and Theil-Sen’s slope methods. Meanwhile, aridity indices were estimated using two different indices. The impacts of meteorological variables on RET were assessed through sensitive analysis by comparing the resulting RETs from artificially disturbed meteorological variables. The results indicated that the RET for 16 stations in Mongolia showed an increasing trend, particularly in the center and south. The calculated RET was higher than precipitation, which means severe droughts in Mongolia. The spatial patterns of RET are significantly influenced by climatic conditions as well as characteristics of the underlying surface (e.g., elevation and vegetation). The mean annual RET decreased from the south to the north, owing to sparse vegetation in the south of Mongolia. The sensitivity analysis revealed that the changes of RET were strongly affected by air temperature and relative humidity.

The hydrography and plankton of the Moray Firth

1986 ◽  
Vol 91 ◽  
pp. 37-56 ◽  
Author(s):  
J. A. Adams ◽  
J. H. A. Martin
Keyword(s):  
North Sea ◽  
Coastal Water ◽  
Standing Stock ◽  
Dry Weight ◽  
Residual Currents ◽  
The North ◽  
Southern Shore ◽  
Moray Firth ◽  
Standing Stocks ◽  
Mixed Water

SynopsisThe Moray Firth forms part of the north British coastal area of the North Sea and is distinguished by its depth, hydrography and plankton from the offshore northern North Sea. The 35·0 or 35·1 × 103 isohaline can be taken as the boundary between the two areas.Geographical and seasonal variations in temperature and salinity are described in terms of a belt of low salinity coastal water in the inner firth and along its southern shore and of “mixed” water to the north and east. During the winter the “mixed” water is warmer than the coastal water, during the summer it is colder. Tidal streams are dominantly semi-diurnal, relatively weak in the inner firth and relatively strong in the outer firth. Residual currents are largely wind driven, and some are caused by tidal effects.Geographical variation in the seasonal changes in the phytoplankton standing stock is related to water column stratification. The early spring standing stocks are highest in the inner firth and off the southern shore. During the summer and early autumn, phytoplankton is most abundant below the pycnocline. Average zooplankton standing stocks increase from 0·2–0·6 g dry weight (100m3) 1 in winter to 1.0 g (100m3) 1 exceptionally 4·5 g (100m3) 1. in summer. Standing stocks in November–December range from 0·3 to 1·8 g (100m3) 1.

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