Comparison of Lake Ontario Zooplankton Communities Between 1967 and 1985: Before and After Implementation of Salmonid Stocking and Phosphorus Control

1987 ◽  
Vol 13 (3) ◽  
pp. 328-339 ◽  
Author(s):  
Ora E. Johannsson
Keyword(s):  
Lake Ontario ◽  
Phosphorus Control ◽  
Before And After ◽  
Zooplankton Communities

Chemical and Biological Changes in Nelson Lake, Ontario Following Experimental Elevation of Lake pH

1977 ◽  
Vol 12 (1) ◽  
pp. 213-232 ◽  
Author(s):  
N.D. Yan ◽  
W.A. Scheider ◽  
P.J. Dillon
Keyword(s):  
Heavy Metal ◽  
Lake Ontario ◽  
Background Concentrations ◽  
Precambrian Shield ◽  
Metal Levels ◽  
Zooplankton Communities ◽  
Shield Lakes

Abstract Intensive studies of Nelson Lake, a Sudbury area lake of intermediate pH ~5.7), were begun in 1975. The chemistry of the lake was typical of that of most PreCambrian Shield lakes except that low alkalinities and high sulphate concentrations were observed along with elevated heavy metal levels. After raising the pH of Nelson Lake to 6.4 by addition of Ca(OH)2 and CaCO3, the metals were reduced to background concentrations. Phytoplankton and Zooplankton communities, which at pH of 5.7 were typical of PreCambrian lakes, were not affected by the experimental elevation of lake pH.

scholarly journals Changes in zooplankton communities of the Lebyazhye system restored lakes

2021 ◽  
Vol 937 (2) ◽  
pp. 022069
Author(s):  
O Y Derevenskaya
Keyword(s):  
Anthropogenic Impacts ◽  
Environmental Parameters ◽  
Lake System ◽  
Area Reduction ◽  
Before And After ◽  
Water Ph ◽  
Pressure Water ◽  
Rehabilitation Measures ◽  
Zooplankton Communities ◽  
Water Catchment

Abstract Ponds rehabilitation projects for the purpose of eco - rehabilitation following significant anthropogenic impacts or degradation are becoming more frequent but not always successful. Therefore, the experience of the restoration of the Lebyazhye system lakes in Kazan city (Russia) is interesting. Previously, the lake system used to consist of four ponds, but due to water catchment area reduction, the area of the lake system also decreased, and only one lake remained. The restoration of the Lebyazhye system lakes was carried out in 2017 and included the deepening of the basin of the Bolshoe and Svetloe Lebyazhye lakes to 4 m, the sealing of the bed of future ponds with bentonite mats, supplying water from Izumrudnoye lake through a pressure water conduit and filling the basin of the lakes with water. The research is devoted to the study of the restoration of zooplankton communities in the Lebyazhye system lakes. For this purpose, the indicators of zooplankton communities before and after eco-rehabilitation measures were compared. After the implementation of eco-rehabilitation measures, significant changes in environmental parameters were observed: the salinity of water decreased, the oxygen content in the water, pH increased. In zooplankton communities, the species richness and diversity increased, new species appeared, as well as those that lived in the lake system earlier before eco-rehabilitation measures were taken.

Food of the Alewife (Alosa pseudoharengus) in Lake Ontario before and after the Establishment of Bythotrephes cederstroemi

1992 ◽  
Vol 49 (10) ◽  
pp. 2009-2019 ◽  
Author(s):  
Edward L. Mills ◽  
Robert O'Gorman ◽  
Joe DeGisi ◽  
Roy F. Heberger ◽  
Robert A. House
Keyword(s):  
Thermal Structure ◽  
Zooplankton Community ◽  
Lake Ontario ◽  
Trophic Levels ◽  
Crustacean Zooplankton ◽  
Alosa Pseudoharengus ◽  
Fish Feeding ◽  
Niagara River ◽  
Bythotrephes Cederstroemi ◽  
Before And After

Diets and length–weight relationships of Lake Ontario alewife (Alosa pseudoharengus) in 1972 differed from those in 1988; the large cladoceran Bythotrephes cederstroemi colonized the lake during the mid-1980's. Micro-crustacean zooplankton were the dominant prey of alewife during April–October in 1972 and 1988. Although Bythotrephes was not found in 1988 net samples, it replaced other zooplankters in the alewife's diet. Typically, tailspines were the only part of Bythotrephes in alewife stomachs; their frequency was high in April–May, diminished rapidly in summer and was very low by fall. In spring 1988, alewife [Formula: see text] were in better condition than in spring 1972 and this may have been due to larger fish feeding more heavily on Bythotrephes. Variation in diet among widely separated sampling sites was due to differences in alewife abundance, stability of thermal structure, progress of zooplankton community development and distance to the mouth of the Niagara River (through which Bythotrephes probably enter the lake in summer and fall). In the Great Lakes, inter- and intralake differences in diet clearly exist, and these must be incorporated into models of alewife planktivory to gain an accurate understanding of energy flow between trophic levels.

scholarly journals Impact of phosphorus control measures on in-river phosphorus retention associated with point source pollution

2005 ◽  
Vol 2 (1) ◽  
pp. 37-72 ◽  
Author(s):  
B. O. L. Demars ◽  
D. M. Harper ◽  
J.-A. Pitt ◽  
R. Slaughter
Keyword(s):  
Sewage Treatment ◽  
Weather Conditions ◽  
Control Measures ◽  
Quality Data ◽  
Short Time Scale ◽  
Phosphorus Retention ◽  
Water Quality Data ◽  
Phosphorus Control ◽  
Before And After ◽  
Environment Agency

Abstract. In-river phosphorus retention alters the quantity and timings of phosphorus delivery to downstream aquatic systems. Many intensive studies of in-river phosphorus retention have been carried out but generally on a short time scale (2-4 years). In this paper, monthly water quality data, collected by the Environment Agency of England and Wales over 12 years (1990-2001), were used to model daily phosphorus fluxes and monthly in-river phosphorus retention in the lowland calcareous River Wensum, Norfolk, UK. The effectiveness of phosphorus stripping at two major sewage treatment works was quantified over different hydrological conditions. The model explained 78% and 88% of the observed variance before and after phosphorus control, respectively. During relatively dry years, there was no net export of phosphorus from the catchment. High retention of phosphorus occurred, particularly during the summer months, which was not compensated for, by subsequent higher flow events. The critical discharge (Q) above which net remobilisation would occur, was only reached during few, high flow events Q25-Q13. Phosphorus removal from the effluent at two major STWs (Sewage Treatment Works) reduced the phosphorus catchment mass balance variability by 20-24% under the Q99-Q1. range of flow conditions. Although the absorbing capacity of the catchment against human impact was remarkable, further phosphorus remedial strategies will be necessary to prevent downstream risks of eutrophication occuring independently of the unpredictable variability in weather conditions.

scholarly journals Changes in Fish Communities of Lake Ontario Coastal Wetlands before and after Remedial Action Plans

ISRN Ecology ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-11
Author(s):  
Titus Seilheimer ◽  
Anhua Wei ◽  
Patricia Chow-Fraser
Keyword(s):  
Coastal Wetlands ◽  
Lake Ontario ◽  
Rank Test ◽  
Action Plans ◽  
Remedial Action ◽  
Species List ◽  
Detection Analysis ◽  
Remedial Action Plans ◽  
Before And After ◽  
Wilcoxon Sign Rank

We conducted a change-detection analysis to determine if improvements in the habitat quality of coastal wetlands could be attributed to Remedial Action Plans (RAPs) of Lake Ontario. We used a 5-km buffer relative to each recent site to “resample” an existing database of spawning/nursery habitat from the early 1980s to derive a “historic” species list associated with thirteen representative wetlands sampled in 2001-2002. For each wetland, we calculated Wetland Fish Index (WFI) scores, which are relative measures of wetland quality having scores ranging from 1 to 5, indicating worst to best conditions, respectively. The mean WFI score of 3.16 for the recent era was significantly higher than that for the historic era of 2.79 (Wilcoxon sign-rank test; P=.04), and this is consistent with the conclusion that lakewide RAPs have been effective in recovering some of the ecological functions of degraded coastal wetlands of Lake Ontario.

Changes in the Nearshore and Offshore Zooplankton Communities in Lake Ontario: 1981–88

1991 ◽  
Vol 48 (8) ◽  
pp. 1546-1557 ◽  
Author(s):  
Ora E. Johannsson ◽  
Edward L. Mills ◽  
Robert O'Gorman
Keyword(s):  
Lake Ontario ◽  
Zooplankton Abundance ◽  
Alosa Pseudoharengus ◽  
Catch Per Unit Effort ◽  
Eastern Basin ◽  
Cladoceran Species ◽  
Large Populations ◽  
Daphnia Galeata Mendotae ◽  
And Shifts ◽  
Zooplankton Communities

We examined trends and factors influencing changes in nearshore and offshore zooplankton abundance and composition in Lake Ontario between 1981 and 1988. In the nearshore (southshore and eastern basin), zooplankton abundance decreased and shifts occurred in the relative abundances of Bosmina longirostris and Daphnia retrocurva (eastern basin) and Daphnia retrocurva and Daphnia galeata mendotae (southshore). These changes could have resulted from increased vertebrate predation or reduced food resources which intensified the effects of predation. In the offshore, the first appearance (FA) of the larger, less common cladoceran species occurred earlier in the season as of 1985. FA was correlated with cumulative epilimnetic temperature (CET) and the catch per unit effort (CPUE) of alewife (Alosa pseudoharengus) [Formula: see text] caught in U.S. waters in the spring. In 1987, when CET was high and CPUE of alewife [Formula: see text] was low, large populations of these cladocerans developed in June and July. Bythotrephes cederstroemi, a recent invader in the Great Lakes, was abundant only in 1987 when the CPUE of alewife was lowest. Changes in zooplankton abundance, development, and composition along the nearshore–offshore gradient reflected effects of temperature, habitat, and planktivory on the community.

scholarly journals Indirect Effects of Copper Sulfate Addition on Zooplankton Communities in Ohio Upground Reservoirs

2015 ◽  
Vol 115 (2) ◽  
pp. 24 ◽  
Author(s):  
Meghan C.W. Williams ◽  
Joseph D. Conroy ◽  
Jeffrey G. Miner ◽  
John R. Farver
Keyword(s):  
Water Supply ◽  
Copper Sulfate ◽  
Yellow Perch ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Negative Effects ◽  
Small Copepod ◽  
Before And After ◽  
Zooplankton Communities ◽  
Sport Fish

Municipal water managers use copper sulfate (CuSO4) to control algae, predominantly phytoplankton, in water supply reservoirs. In multiple-purpose upground reservoirs in northwestern Ohio, CuSO4 application regimens vary from no application to over 600 µg Cu/L/year. Whereas CuSO4 effectively suppresses phytoplankton growth, it also has documented toxicities to zooplankton, which serve as forage for stocked sport fish. Consequently, CuSO4 application benefits one upground reservoir use (water supply) while potentially negatively affecting another (sport fishing). This research sought to directly compare copper concentrations ([Cu]) in dissolved and particulate fractions with corresponding zooplankton community composition and abundance both before and after CuSO4 application in Ohio upground reservoirs. Copper concentrations and zooplankton community characters were measured at four upground reservoirs (n = 2 treated with CuSO4 and n = 2 untreated) over multiple weeks during summer 2010. Total [Cu] in treated reservoirs increased by as much as 428% from pre- (mean = 16.5 µg/L) to post-application (mean = 70.7 µg/L); concomitantly, zooplankton biomass and density decreased by as much as 93%. Post-application zooplankton communities shifted to dominance by small copepod nauplii from a mixed community that included larger cladocerans. Copepod nauplii represent a less-suitable food source for stocked juvenile yellow perch Perca flavescens. Thus, short-term negative effects to the zooplankton community may result from CuSO4 applications, indirectly affecting stocked sport fish success.

Deformation Replication

1970 ◽  
Vol 28 ◽  
pp. 280-281
Author(s):  
J. Temple Black
Keyword(s):  
Cutting Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Rake Face ◽  
Orthogonal Machining ◽  
Aluminum Chips ◽  
Before And After ◽  
Materials Used ◽  
Glass Knife ◽  
Very High

Tool materials used in ultramicrotomy are glass, developed by Latta and Hartmann (1) and diamond, introduced by Fernandez-Moran (2). While diamonds produce more good sections per knife edge than glass, they are expensive; require careful mounting and handling; and are time consuming to clean before and after usage, purchase from vendors (3-6 months waiting time), and regrind. Glass offers an easily accessible, inexpensive material ($0.04 per knife) with very high compressive strength (3) that can be employed in microtomy of metals (4) as well as biological materials. When the orthogonal machining process is being studied, glass offers additional advantages. Sections of metal or plastic can be dried down on the rake face, coated with Au-Pd, and examined directly in the SEM with no additional handling (5). Figure 1 shows aluminum chips microtomed with a 75° glass knife at a cutting speed of 1 mm/sec with a depth of cut of 1000 Å lying on the rake face of the knife.

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