Chemistry of Surface Sediments of Sixteen Lakes in the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 277-294 ◽  
Author(s):  
G. J. Brunskill ◽  
D. Povoledo ◽  
B. W. Graham ◽  
M. P. Stainton
Keyword(s):  
Lake Sediments ◽  
Lake Sediment ◽  
Chemical Weathering ◽  
Major Ions ◽  
Fine Fraction ◽  
Dry Weight ◽  
Terrestrial Vegetation ◽  
Experimental Lakes Area ◽  
Sediment Samples ◽  
Northwestern Ontario

This paper contains some descriptive chemical data on bedrock, soils, and profundal lake sediments of the Experimental Lakes Area (ELA). The acid granodiorite bedrock and the plagioclase–K-feldspar–quartz glacial drift of the region exhibit low rates of chemical weathering. Terrestrial vegetation, soil organic matter, and the fine fraction of the glacial drift are concentrated in the lake sediments. The major minerals of the lake sediments are quartz, plagioclase, K-feldspar, illite, chlorite, kaolinite. Loss on ignition for the lake sediment samples varies from 18 to 62% dry weight, organic carbon from 8 to 34% dry weight, total nitrogen from 0.9 to 3.5% dry weight, and total phosphorus from 0.1 to 0.3% dry weight. These surficial lake sediment samples are 88–96% water, and concentrations of major ions in sediment interstitial water are 1.5–5 times the concentration of major ions in lake water.

The Effect of pH on Methyl Mercury Production and Decomposition in Lake Sediments

1985 ◽  
Vol 42 (4) ◽  
pp. 685-692 ◽  
Author(s):  
P. S. Ramial ◽  
John W. M Rudd ◽  
Akira Furutam ◽  
Luying Xun
Keyword(s):  
Lake Sediments ◽  
Methyl Mercury ◽  
Inorganic Mercury ◽  
Mercury Methylation ◽  
Surficial Sediments ◽  
Experimental Lakes Area ◽  
Effect Of Ph ◽  
Northwestern Ontario ◽  
Acidified Lakes ◽  
Mercury Production

Mercury methylation was measured in surficial sediments taken from unacidified and experimentally acidified lakes in the Experimental Lakes Area, northwestern Ontario. A reduction in the pH of sediments lowered the rate of 203Hg methylation. Methylation was undetectable at pH <5.0. This decrease in mercury methylation was probably related to a shortage of available inorganic mercury when the pH of the sediment porewater was reduced. Below pH 6.0, inorganic mercury concentrations in porewater, measured with 203Hg, were reduced to less than 20% of that found at unaltered pH. A comparison of methylation and demethylation rates was made at various pH's. The rate of demethylation decreased to a lesser extent than methylation as the pH was lowered. This research indicates that enhanced mercury methylation in the sediment is not responsible for the observed increase in mercury levels in fish from acidified lakes.

Vertical Distribution and Seasonal Abundance of Zooplankton in Two Shallow Lakes of the Experimental Lakes Area, Northwestern Ontario

1971 ◽  
Vol 28 (2) ◽  
pp. 245-256 ◽  
Author(s):  
D. W. Schindler ◽  
Bengt Novén
Keyword(s):  
Vertical Distribution ◽  
Dry Weight ◽  
Distribution Patterns ◽  
Zooplankton Biomass ◽  
Seasonal Abundance ◽  
Experimental Lakes Area ◽  
Leptodora Kindtii ◽  
Northwestern Ontario ◽  
Vertical Distributions ◽  
Diurnal Movement

Seasonal variations in the abundance of zooplankton were studied in lakes 122 and 132 for a period of 10 months beginning in mid-May 1968. Seasonal dynamics of various species are discussed in relation to their patterns in the Canadian Shield and in other localities.Day and night vertical distributions for each lake were sampled on two dates in summer. Three species of rotifers migrated diurnally in lake 122, but no evidence of diurnal movement was found in lake 132. All crustaceans studied in both lakes migrated vertically to some degree, except for nauplius larvae and Leptodora kindtii. There was little difference in vertical distribution patterns on the two dates studied.Average zooplankton biomass in the two lakes was calculated and compared with that found in other studies. Average zooplankton biomass during the ice-free season was 72 and 156 mg/m3 dry weight for lakes 122 and 132, respectively. Dominant species in both lakes were Diaptomus minutus, Cyclops bicuspidatus thomasi, Holopedium gibberum, and Bosmina longirostris. Ecological tolerances for rotifer species agreed well with those found for Swedish waters.

Changes in methyl mercury concentrations in zooplankton from four experimental reservoirs with differing amounts of carbon in the flooded catchmentsThis paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 1910-1919 ◽  
Author(s):  
Britt D. Hall ◽  
Katharine A. Cherewyk ◽  
Michael J. Paterson ◽  
R. (Drew) A. Bodaly
Keyword(s):  
Food Web ◽  
Methyl Mercury ◽  
Dry Weight ◽  
Experimental Lakes Area ◽  
Organic C ◽  
Dissolved Organic C ◽  
Northwestern Ontario ◽  
Highly Correlated ◽  
Source Waters

Methyl mercury (MeHg) concentrations in zooplankton were compared from four experimental reservoirs at the Experimental Lakes Area in northwestern Ontario, Canada, to test the hypothesis that increases in concentrations of MeHg in zooplankton would be proportional to C availability. The experimental reservoirs included three upland reservoirs flooded between 1999 and 2003 that differed in amounts of flooded organic terrestrial C (high, medium, and low C) and an experimental reservoir created over a wetland–peatland complex in 1993. After flooding, MeHg in zooplankton increased from <100 ng·g dry weight–1 in inflow source waters to >500 ng·g dry weight–1 in all reservoirs. In the first two years of flooding, MeHg in zooplankton was not correlated with amounts of flooded C, but the rates of decline in mean annual concentrations were negatively correlated with the amount of C stored in flooded catchments. Concentrations of MeHg in zooplankton were highly correlated with MeHg concentrations in unfiltered water, with reductions in bioaccumulation associated with increases in dissolved organic C and decreases in pH. Overall, our results suggest that reservoir designs that minimize the amount of flooded terrestrial C should result in shorter periods of elevated MeHg in the food web.

Atmospheric Deposition of Nutrients and Major Ions at the Experimental Lakes Area in Northwestern Ontario, 1970 to 1982

1987 ◽  
Vol 44 (S1) ◽  
pp. s206-s214 ◽  
Author(s):  
G. A. Linsey ◽  
D. W. Schindler ◽  
M. P. Stainton
Keyword(s):  
Major Ions ◽  
Ion Concentration ◽  
Agricultural Activity ◽  
Chemical Parameters ◽  
Experimental Lakes Area ◽  
Hydrogen Ion Concentration ◽  
Northwestern Ontario ◽  
Agricultural Areas ◽  
Annual Deposition ◽  
Precipitation Events

Up to 24 chemical parameters have been monitored in individual precipitation events captured in bulk collectors at the Experimental Lakes Area (ELA), from 1970 to 1982. Although sample to sample variation was high, seasonal trends were discernible for several ions. Annual mean concentrations of H+, NO3−, and SO42− were low and quite constant until 1981, but increased dramatically in 1982. Hydrogen ion concentration increased by an average of 0.63 μEq∙L−1 over this period. The order of annual average cation dominance was Ca2+ > NH4+ > H+ > Mg2+ > K+. The dominant anion was SO42−, followed by NO3− > Cl−. Calcium, Mg2+, SO42−, Si, suspended P and N, total dissolved P and N, and total ionic concentrations were greatest in spring and fall, correlating with periods of maximum agricultural activity on the prairies, over 250 km away. Concentrations of NO3− and H+ were higher in snow than in rain, while SO42−, Ca2+, Mg2+, and NH4+ were greater in rain. The total deposition of most substances was higher in summer than in winter, because of the greater proportion of annual precipitation occurring in summer months. A comparison with other sites revealed higher Ca2+ and NH4+ at all sites near agricultural areas, and higher H+, SO42−, and NO3− at sites in eastern North America. A comparison of 1980 bulk versus wet-only chemistry indicated that dryfall contributed 52% of the total annual deposition of Cl−, 22% of the SO42−, 0% of the NO3−, 48% of the Mg2+, 31% of the NH4+, 28% of the Ca2+, and 8% of the Na+. Charge balances were excellent for both wet and bulk samples.

Relationships Between Dipteran Emergence and Phytoplankton Production in the Experimental Lakes Area, Northwestern Ontario

1980 ◽  
Vol 37 (3) ◽  
pp. 523-533 ◽  
Author(s):  
I. J. Davies
Keyword(s):  
Euphotic Zone ◽  
Dry Weight ◽  
Single Equation ◽  
Phosphorus Loading ◽  
Phytoplankton Production ◽  
Lake Depth ◽  
Lake Productivity ◽  
Experimental Lakes Area ◽  
Surface Distribution ◽  
Northwestern Ontario

Dipteran emergence was monitored at the Experimental Lakes Area (ELA) between 1973 and 1977 in seven lakes of different trophic status. The data were used to develop a number of equations which related the quantity and spatial distribution of average annual emergence to lake productivity. These models explained > 94% of the variation in mean emergent biomass among lakes or > 76% of the variation in numbers of emergent Diptera in terms of phytoplankton production or phosphorus loading. On average, ELA lakes produced 40.8 dipteran adults (9 mg dry weight) per gram carbon fixed by phytoplankton. A single equation for all lakes predicts the surface distribution of emergent biomass, relative to lake depth at any location, from vertical profiles of phytoplankton production. The mean size of dipteran adults was related to lake depth at the point of emergence and average phytoplankton production. An empirical model which used data on the vertical profile, and lake average, of phytoplankton production was developed to predict the number of Diptera emerging from each depth. The maximum depth of emergence was related to depth of the euphotic zone and average phytoplankton production in each lake. Initial tests suggested that the models may provide useful predictions of dipteran emergence for a wider spectrum of lakes.Key words: aquatic insects, Diptera, Chironomidae, eutrophication, primary production

Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments of the Brisbane River (Australia) – Preliminary Results

1989 ◽  
Vol 21 (2) ◽  
pp. 161-165 ◽  
Author(s):  
S. I. Kayal ◽  
D. W. Connell
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
River Estuary ◽  
Dry Weight ◽  
Weight Basis ◽  
Sediment Samples ◽  
Preliminary Results ◽  
Treated Sewage ◽  
Polycyclic Aromatic ◽  
Petroleum Refineries

Results of the analysis of twenty-three composite sediment samples revealed that PAHs are widely distributed in the Brisbane River estuary. Mean concentrations for individual compounds, on a dry weight basis, ranged from 0.03 µg/g for dibenz [ah] anthracene to 2.34 µg/g for fluoranthene. Observed PAH assemblages were rich in compounds having pyrolytic origins. However, the presence of petroleum derived compounds was indicative of the importance of petroleum as a PAH source in the estuary. Petroleum refineries, a coal loading terminal and a major treated sewage outfall located at the mouth were not indicated as major contributing sources of PAH pollution in the estuary.

Monitoring of environmental effects and process performance during biological treatment of sediment from the petroleum Harbour in Amsterdam

1998 ◽  
Vol 37 (6-7) ◽  
pp. 395-402
Author(s):  
Guus C. Stefess
Keyword(s):  
Environmental Effects ◽  
Organic Contaminants ◽  
Biological Treatment ◽  
Biological Process ◽  
Froth Flotation ◽  
Fine Fraction ◽  
Dry Weight ◽  
Pilot Project ◽  
Mineral Oil ◽  
Silt Fraction

A full-scale (470 m3) process for biological treatment of dredging spoil from the Petroleum Harbour in Amsterdam has been monitored during a pilot project. The dredging spoil was heavily polluted with polycyclic aromatic hydrocarbons (PAH) and mineral oil. The remediation chain involved dredging, transport of dredged spoil, hydrocyclone separation, froth flotation of the coarse particles, and biological treatment of the silt fraction (&lt;20 μm) in stirred bioractors. The independent monitoring was aimed at recording the environmental effects, product quality and performance of the biological process. Hydrocyclone separation (cut point 20 m) resulted in two bulk streams: 65% sand and 30% silt (based on total dry weight of the input). The sand was cleaned and could be reused as building material. PAH and mineral oil were successfully concentrated in the silt fraction (&lt;20 μm), which was treated biologically. Biological treatment during continuous feeding of fine fraction, at a residence time of 8-10 days for the entire bioreactor system, resulted in considerably reduced mineral oil and PAH contents. Furthermore, the leaching of organic contaminants was reduced, as well as the ecotoxicity. The obtained silt product however did not meet the demands, and had to be landfilled. Minor emissions of contaminants were measured in wastewater and offgas. The energy and chemicals consumption were acceptable. The biological process appears to be promising for the treatment of less-severely contaminated dredged material.

Land water linkages: influences of riparian deforestation on lake thermocline depth and possible consequences for cold stenotherms

1997 ◽  
Vol 54 (6) ◽  
pp. 1299-1305 ◽  
Author(s):  
Robert France
Keyword(s):  
Thermal Stratification ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Thermocline Depth ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Riparian Trees ◽  
Tree Removal ◽  
Riparian Tree ◽  
Land Water

The purpose of the present study was to determine if riparian deforestation would expose lake surfaces to stronger winds and therefore bring about deepening of thermoclines and resulting habitat losses for cold stenotherms such as lake trout (Salvelinus namaycush). Removal of protective riparian trees through wind blowdown and two wildfires was found to triple the overwater windspeeds and produce thermocline deepening in two lakes at the Experimental Lakes Area. A survey of thermal stratification patterns in 63 northwestern Ontario lakes showed that lakes around which riparian trees had been removed a decade before through either clearcutting or by a wildfire were found to have thermocline depths over 2 m deeper per unit fetch length compared with lakes surrounded by mature forests. Riparian tree removal will therefore exacerbate hypolimnion habitat losses for cold stenotherms that have already been documented to be occurring as a result of lake acidification, eutrophication, and climate warming.

Cleaning of lake sediment samples for diatom oxygen isotope analysis

2004 ◽  
Vol 31 (3) ◽  
pp. 391-401 ◽  
Author(s):  
David W. Morley ◽  
Melanie J. Leng ◽  
Anson W. Mackay ◽  
Hilary J. Sloane ◽  
Patrick Rioual ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Lake Sediment ◽  
Isotope Analysis ◽  
Sediment Samples

Chemical weathering and Sr flux from the silicate lithology dominated fluvial system: Insights from major ions, dissolved Sr and 87Sr/86Sr of the teesta headwaters, Sikkim Himalaya

2021 ◽  
pp. 105171
Author(s):  
Satyabrata Das ◽  
Santosh K. Rai ◽  
Waliur Rahaman ◽  
Saurabh Singhal ◽  
Shushanta Sarangi
Keyword(s):  
Chemical Weathering ◽  
Major Ions ◽  
Fluvial System ◽  
Sikkim Himalaya
Sign in / Sign up

Export Citation Format

Share Document