Response of Amphipoda and Trichoptera to Lake Fertilization in the Canadian Arctic

1992 ◽  
Vol 49 (11) ◽  
pp. 2354-2362 ◽  
Author(s):  
John K. Jorgenson ◽  
Harold E. Welch ◽  
Martin F. Curtis
Keyword(s):  
Life Cycle ◽  
Primary Production ◽  
Northwest Territories ◽  
Canadian Arctic ◽  
Phytoplankton Production ◽  
Natural Conditions ◽  
Gammarus Lacustris ◽  
The Third ◽  
Biomass Ratio ◽  
Lake Fertilization

Small oligotrophic lakes at Saqvaqjuac, Northwest Territories, were fertilized with phosphorus and nitrogen after 2 yr of study and the response of macroinvertebrates to increased primary production was followed for 3 yr. The amphipod Gammarus lacustris lacustris (G. O. Sars) had a 2-yr life cycle, with three cohorts present in August. Biomass under natural conditions was approximately 0.1–0.2 g dry wt∙m−2. Gammarus responded immediately to a doubling of phytoplankton production with increased survival of young-of-year. Gammarus biomass increased steadily to 0.9 g dry wt∙m−2 and had not stabilized after 3 yr of fertilization. Trichoptera were represented by three species, with Grensia praeterita composing the bulk of the biomass, followed by Apatania zonella and an uncommon Hesperophylax species. Trichoptera biomass ranged from 0.04 to 0.3 g dry wt∙m−2 before fertilization. Response to increased primary production was slow, beginning in year 2 of fertilization. Trichoptera biomass had doubled by the third year of fertilization but was probably several years from equilibrium. Application of benthos models, in addition to the data, suggested that the production to biomass ratio was between 1 and 2, averaging 1.5.

Emergence of Chironomidae (Diptera) in Fertilized and Natural Lakes at Saqvaqjuac, N.W.T.

1988 ◽  
Vol 45 (4) ◽  
pp. 731-737 ◽  
Author(s):  
Harold E. Welch ◽  
John K. Jorgenson ◽  
Martin F. Curtis
Keyword(s):  
Primary Production ◽  
Phytoplankton Production ◽  
Experimental Lakes Area ◽  
Natural Lakes ◽  
Before And After ◽  
Mean Size ◽  
Apparent Reason ◽  
Total Primary Production ◽  
Latitudinal Range ◽  
Lake Fertilization

Chironomid emergence was quantified in four small lakes at Saqvaqjuac, N.W.T. (63°39′N), before and after lake fertilization. Emerging biomass responded immediately to increased phytoplankton production, reaching equilibrium the following year. Emergence from the reference lake was extremely variable, for no apparent reason. The emergence – phytoplankton production relationships found by Davies for the Experimental Lakes Area (~49°N) were generally valid for Saqvaqjuac lakes and Char Lake (74°42′), except that (1) biomass was better correlated than numbers because of increased mean size with increasing latitude and (2) total primary production was a better predictor than phytoplankton production alone because benthic photosynthesis increases with increasing latitude. Chironomid production seems to be a predictable function of total primary production throughout the latitudinal range of the small Canadian lakes examined.

scholarly journals Regional variability of acidification in the Arctic: a sea of contrasts

2014 ◽  
Vol 11 (2) ◽  
pp. 293-308 ◽  
Author(s):  
E. E. Popova ◽  
A. Yool ◽  
Y. Aksenov ◽  
A. C. Coward ◽  
T. R. Anderson
Keyword(s):  
Climate Change ◽  
Primary Production ◽  
Arctic Ocean ◽  
Canadian Arctic ◽  
Atmospheric Co2 ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Regional Variability ◽  
The Arctic Ocean ◽  
The Impact

Abstract. The Arctic Ocean is a region that is particularly vulnerable to the impact of ocean acidification driven by rising atmospheric CO2, with potentially negative consequences for calcifying organisms such as coccolithophorids and foraminiferans. In this study, we use an ocean-only general circulation model, with embedded biogeochemistry and a comprehensive description of the ocean carbon cycle, to study the response of pH and saturation states of calcite and aragonite to rising atmospheric pCO2 and changing climate in the Arctic Ocean. Particular attention is paid to the strong regional variability within the Arctic, and, for comparison, simulation results are contrasted with those for the global ocean. Simulations were run to year 2099 using the RCP8.5 (an Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5) scenario with the highest concentrations of atmospheric CO2). The separate impacts of the direct increase in atmospheric CO2 and indirect effects via impact of climate change (changing temperature, stratification, primary production and freshwater fluxes) were examined by undertaking two simulations, one with the full system and the other in which atmospheric CO2 was prevented from increasing beyond its preindustrial level (year 1860). Results indicate that the impact of climate change, and spatial heterogeneity thereof, plays a strong role in the declines in pH and carbonate saturation (Ω) seen in the Arctic. The central Arctic, Canadian Arctic Archipelago and Baffin Bay show greatest rates of acidification and Ω decline as a result of melting sea ice. In contrast, areas affected by Atlantic inflow including the Greenland Sea and outer shelves of the Barents, Kara and Laptev seas, had minimal decreases in pH and Ω because diminishing ice cover led to greater vertical mixing and primary production. As a consequence, the projected onset of undersaturation in respect to aragonite is highly variable regionally within the Arctic, occurring during the decade of 2000–2010 in the Siberian shelves and Canadian Arctic Archipelago, but as late as the 2080s in the Barents and Norwegian seas. We conclude that, for future projections of acidification and carbonate saturation state in the Arctic, regional variability is significant and needs to be adequately resolved, with particular emphasis on reliable projections of the rates of retreat of the sea ice, which are a major source of uncertainty.

Description of the pupa and redescription of the third instar of Phileurus valgus (Olivier) (Coleoptera: Scarabaeidae: Dynastinae: Phileurini)

Zootaxa ◽  
2017 ◽  
Vol 4290 (3) ◽  
pp. 571
Author(s):  
MARIO G. IBARRA-POLESEL ◽  
NESTOR G. VALLE ◽  
JHON C. NEITA-MORENO ◽  
MIRYAM P. DAMBORSKY
Keyword(s):  
United States ◽  
Life Cycle ◽  
West Indies ◽  
New World ◽  
Common Species ◽  
Southern United States ◽  
Immature Stages ◽  
The West ◽  
The Third ◽  
Third Stage

Phileurus valgus (Olivier) (Coleoptera: Scarabaeidae: Dynastinae: Phileurini) is a common species widely distributed from the southern United States to Argentina and the West Indies. In this work the immature stages are described and illustrated based on specimens from Argentina. A key to the known third-stage larvae of New World Phileurini species is provided and updated. Notes on the life cycle and natural history are also included. 

scholarly journals Biologi Stenocranus pacificus Kirkaldy (Hemiptera: Delphacidae) pada tanaman jagung (Zea mays L.) di rumah kasa

2020 ◽  
Vol 17 (2) ◽  
pp. 104
Author(s):  
Dosma Ulina Simbolon ◽  
Maryani Cyccu Tobing ◽  
Darma Bakti
Keyword(s):  
Zea Mays ◽  
Life Cycle ◽  
Sex Ratio ◽  
Zea Mays L ◽  
Instar Nymph ◽  
Fourth Instar ◽  
The Third ◽  
First Instar ◽  
Corn Plants ◽  
North Sumatra

<p><em>Stenocranus pacificus </em>Kirkaldy (Hemiptera: Delphacidae) is destructive pest on corn plants in South Lampung and it has been reported to cause corn damages in North Sumatra. The  objective of this research was to study some aspects biology of <em>S. pacificus</em> on corn plants in screenhouse. The research was conducted by observing the biology of <em>S. pacificus</em> that was reared on corn plants in screenhouse.<em> </em>The results showed that life cycle of <em>S. pacificus </em>was 38–47 (41,60 ± 3,19) days: egg was 9–11 (10,20 ± 0,79) days, the first instar nymph was 3–4 (3,70 ± 0,48) days, the second instar nymph was 3–4 (3,90 ± 0,32) days, the third instar nymph was 3–4 (3,70 ± 0,48) days, the fourth instar nymph was 3–4 (3,80 ± 0,42) days, and the fifth instar nymph was 3–4 (3,60 ± 0,52) days. Age of female was 13–17 (15,30 ± 1,34) days. It was longer than age of male which was 8–12 (10,10 ± 1,20) days. Female could produce 181–214 (197,60 ± 11,64) eggs during its life. The sex ratio was 1:1,98.</p>

Primary Production and Phytoplankton in the Experimental Lakes Area, Northwestern Ontario, and other Low-Carbonate Waters, and a Liquid Scintillation Method for Determining 14C Activity in Photosynthesis

1971 ◽  
Vol 28 (2) ◽  
pp. 189-201 ◽  
Author(s):  
D. W. Schindler ◽  
S. K. Holmgren
Keyword(s):  
Primary Production ◽  
Liquid Scintillation ◽  
Species Abundance ◽  
Euphotic Zone ◽  
Phytoplankton Production ◽  
Phytoplankton Species ◽  
Experimental Lakes Area ◽  
Phytoplankton Species Composition ◽  
Northwestern Ontario ◽  
Filtration Error

A modified 14C method is described for measuring phytoplankton production in low-carbonate waters. The procedure includes the use of the Arthur and Rigler (Limnol. Oceanogr. 12: 121–124, 1967) technique for determining filtration error, liquid scintillation counting for determining the radioactivity of membrane filters and stock 14C solutions, and gas chromatography for measuring total CO2.Primary production, chlorophyll a, and total CO2 were measured for two dates in midsummer from each of several lakes in the Experimental Lakes Area (ELA), ranging from 1 to 1000 ha in area and from 2 to 117 m in maximum depth. Phytoplankton species abundance and biomass were determined for the same dates. Production ranged from 0.02 to 2.12 gC/m3∙day and from 0.179 to 1.103 g C/m2∙day. Chlorophyll ranged from 0.4 to 44 mg/m3 and from 5 to 98 mg/m2 in the euphotic zone. The corresponding ranges for live phytoplankton biomass were 120–5400 mg/m3 and 2100–13,400 mg/m2. Chrysophyceae dominated the phytoplankton of most of the lakes.A system for classifying the lakes in terms of phytoplankton species composition and production–depth curves is developed.

Social Network Service for Scientists Difficulties Facing E-Publishing over Cloud Computing

2016 ◽  
Vol 7 (3) ◽  
pp. 10-20 ◽  
Author(s):  
Evon M. O. Abu-Taieh
Keyword(s):  
Cloud Computing ◽  
Social Network ◽  
Life Cycle ◽  
Search Engines ◽  
University Ranking ◽  
Network Service ◽  
Social Network Service ◽  
H Index ◽  
The Third ◽  
Research Document

This paper illustrated the difficulties facing e-publishing over cloud computing pertaining to social network service for scientists from three axioms: the life cycle of the research document, an explanation of what a researcher juggles during the course of the production of the document related to research. Then this paper discussed discovering study of the researcher knowledge pertaining to both social network service for scientists, scholarly search engines and citation indices. The first axiom reflected the life cycle of the research paper and how each phase affects and influences the next phase. The second axiom showed the researcher worries and the different tasks that a scholar juggles: research financial support, institutional laws and regulations, time & money, legality and copy rights, language barrier, tech savvy, web metrics & university ranking. The third axiom was a discovering study that explored the weakness of the scholar pertaining to his/her knowledge about citation indices. Scholar's knowledge of social network service for scientists and citation indices like: ResearchGate, Google scholar, and academia.edu, Zotero, Coins, and figshare. CiteSeerX, getCITED, MyScienceWork, Mendeley; In addition, citation indices pertaining to Social network service for scientists and scholar search engines: i10-index, h- index, SCI, SSCI, and RG score.

LIFE CYCLE OF THE NYMPH FLY PALAEODIPTERON WALKERI IDE 1965 (DIPTERA: NYMPHOMYIIDAE) IN THE WHITE MOUNTAINS OF SOUTHERN QUÉBEC

1989 ◽  
Vol 121 (7) ◽  
pp. 603-607 ◽  
Author(s):  
P.P. Harper ◽  
Michel Lauzon
Keyword(s):  
Life Cycle ◽  
Larval Stage ◽  
White Mountains ◽  
Larval Instars ◽  
The Third ◽  
Summer Generation

AbstractCollections of larvae over 1 year in the River Clinton in the White Mountains of southern Québec indicated that Palaeodipteron walkeri Ide is bivoltine and that there are five larval instars. In April, larvae were in their fourth and fifth instars. Adults emerging in May and June gave rise to a summer generation in which most individuals emerged in August and September. The offspring of these adults, together with stragglers from the summer generation, formed an overwintering generation. Overwintering was completed in the larval stage, mainly the third and fourth instars. There was some growth in winter and development increased in the spring. Our data were compared with previously published observations; although no discrepancy occurred, our interpretation was different. Previous schemes proposed for the life cycle in this species were based on few specimens and lacked winter observations.

scholarly journals Amblyomma rotundatum (Koch, 1844) (Acari: Ixodidae) two-host life-cycle on Viperidae snakes

2010 ◽  
Vol 19 (3) ◽  
pp. 174-178 ◽  
Author(s):  
Daniel Sobreira Rodrigues ◽  
Ricardo Maciel ◽  
Lucas Maciel Cunha ◽  
Romário Cerqueira Leite ◽  
Paulo Roberto de Oliveira
Keyword(s):  
Life Cycle ◽  
North America ◽  
Relative Humidity ◽  
Total Duration ◽  
Ixodid Tick ◽  
Natural Conditions ◽  
South Central ◽  
Controlled Conditions ◽  
In Captivity ◽  
Host Life

Amblyomma rotundatum is an ixodid tick that infests ectothermic animals and reproduces exclusively by parthenogenesis. This tick has been frequently reported to infest reptiles and amphibians, under natural conditions and sometimes in captivity. It was described in Brazil and several other countries of South, Central and North America. Although many studies have reported aspects of its biology, none of them has used regularly either ophidian as hosts, or controlled temperature, humidity and luminosity for parasitic stages. The objective of this experiment was to study the life cycle of A. rotundatum feeding on Viperidae snakes under room controlled conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and 12:12 hours photoperiod for parasitic stages, and under B.O.D incubator conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and scotophase for non-parasitic stages. The total duration of the life cycle ranged from 56 to 163 days (mean of 105 days). Two-host life cycle was observed for most of the ixodid population studied.

Communications facilities and user problems in the Canadian Arctic

Polar Record ◽  
1968 ◽  
Vol 14 (90) ◽  
pp. 305-314
Author(s):  
T. Ringereide
Keyword(s):  
Soviet Union ◽  
Northwest Territories ◽  
Indian Population ◽  
Total Population ◽  
Canadian Arctic ◽  
Yukon Territory ◽  
Land Area ◽  
Northern Boundary ◽  
The Soviet Union ◽  
The World

The total area of Canada (land area and fresh water) is around 10 million sq km, making it the second largest country in the world, second only to the Soviet Union.For various historic and economic reasons Canada's population of 20 million is very largely concentrated in the southern part of the country, with about twothirds of the population living in large urban centres. The heavy broken line on Fig 1 shows the northern boundary of the densely populated portion of Canada. Only 1·5 per cent of Canada's total population, or 300000 people, live north of this frontier, and out of this total only about 38000 live in the Yukon Territory and the Northwest Territories. The Yukon has a population of only twenty seven people per 1000 sq km, and the Northwest Territories of eight people per 1000 sq km. The total Eskimo population in both territories is about 13600 and the total Indian population some 8000.

Primary Productivity of Southern Indian Lake before, during, and after Impoundment and Churchill River Diversion

1984 ◽  
Vol 41 (4) ◽  
pp. 591-604 ◽  
Author(s):  
R. E. Hecky ◽  
S. J. Guildford
Keyword(s):  
Light Intensity ◽  
Primary Production ◽  
Water Column ◽  
Primary Productivity ◽  
Phosphorus Deficiency ◽  
Light Environment ◽  
Phytoplankton Production ◽  
Light Penetration ◽  
The Mean ◽  
Chlorophyll Concentrations

The primary productivity of seven regions of Southern Indian Lake and neighboring Wood Lake was measured during open-water seasons from 1974 to 1978. The lake had regional differences in chlorophyll concentrations and daily rates of integral primary production in 1974 and 1975 prior to impoundment of the lake. Regions receiving Churchill River flow tended to have higher chlorophyll concentrations and production rates than those regions marginal to the flow. Impoundment of the lake resulted in higher efficiencies of primary production in all regions, as indicated by higher light-saturated rates of carbon uptake per unit chlorophyll and by higher initial slopes of the hyperbolic light response relation of the phytoplankton. Many large basins of the lake had light penetration reduced by high concentrations of suspended sediment from eroding shorelines, while other areas had relatively unchanged light penetration. The increased efficiency of carbon fixation per unit chlorophyll resulted in higher rates of integral production in those regions where light penetration was not greatly affected. Daily rates of integral primary production in lake regions where light penetration had decreased markedly were not significantly different after impoundment because efficiencies of light utilization were higher. Comparison of the mean water column light intensities for those turbid regions with the values of Ik (light intensity at the onset of light saturation) for phytoplankton indicated that these turbid regions are now light deficient on average. Phosphorus deficiency, as indicated by alkaline phosphatase activity per unit ATP, which was present before impoundment, has been eliminated as the mean water column light intensity declined below 5 mEinsteins∙m−2∙min−1. The light environment of a new reservoir can be a significant determinant of integral production, and predicting the consequences of impoundment on phytoplankton production requires accurate prediction of the light environment.

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