Accumulation and recycling of PCBs and PAHs in artificially eutrophied Lake 227

1999 ◽  
Vol 56 (4) ◽  
pp. 650-660 ◽  
Author(s):  
Jeff D Jeremiason ◽  
Steven J Eisenreich ◽  
Michael J Paterson
Keyword(s):  
Phytoplankton Community ◽  
Sediment Accumulation ◽  
Point Sources ◽  
Accumulation Rates ◽  
Experimental Lakes Area ◽  
High Accumulation ◽  
Northwestern Ontario ◽  
Polycyclic Aromatic ◽  
Contaminant Accumulation

The influence of lake trophic status on the cycling and burial of polychlorinated biphenyls (PCB's) and polycyclic aromatic hydrocarbons (PAH's) was examined in Lake 227 (L227), an artificially eutrophied lake in the Experimental Lakes Area, northwestern Ontario, Canada. Sedimentary accumulation of PCB's, PAH's, and organic carbon (OC) was determined pre- and post-eutrophication in L227 and compared with accumulation in other regional lakes. Mass and OC accumulation increased an average of 1.4 and 2.0 times, respectively, since nutrient addition began in June 1969. ΣPCB and ΣPAH sediment accumulation rates and profiles in L227 were similar to those in Lake Superior and other proximate and midlatitude lakes unimpacted by point sources. Eutrophication did not increase contaminant accumulation. In general, individual PAH accumulation rates declined following eutrophication, which coincided with similar signals elsewhere. Perylene declined markedly (4 times) since eutrophication as a result of decreased in situ formation. An increase in OC accumulation did not enhance contaminant accumulation in L227 because phytoplankton community structure shifted to species characterized by lower bioaccumulation factors, and water column recycling rates were high. Accumulation rates of mass, OC, PCB's, and PAH's, when compared with ice-free settling fluxes in 1993 and 1994, exhibited similar recycling ratios in eutrophic L227 and oligotrophic L110 due to the efficient preservation of organic matter in sediments.

Cladocera Community Response to Experimental Eutrophication in Lake 227 as Recorded in Laminated Sediments

1994 ◽  
Vol 51 (10) ◽  
pp. 2312-2321 ◽  
Author(s):  
Brenda J. Hann ◽  
Peter R. Leavitt ◽  
Philip S. S. Chang
Keyword(s):  
Standing Crop ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Community Response ◽  
Laminated Sediments ◽  
Accumulation Rates ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Annually Laminated Sediments ◽  
Chemical Conditions

The response of pelagic zooplankton to experimental fertilization was compared with the fossil record of Cladocera obtained from the annually laminated sediments of Lake 227, Experimental Lakes Area, northwestern Ontario. Constrained cluster analysis of both total fossil Cladocera and littoral chydorid communities clearly distinguished between pre- and post-eutrophication communities and further differentiated between years of high and low nitrogen:phosphorus fertilization ratios. However, there were few chydorid species extirpations resulting from the manipulation. Total chydorid accumulation rates and indices of species diversity, richness, and equitability were relatively constant over the last century and were not affected by fertilization. Among pelagic Cladocera, Bosmina longirostris abundance declined > 60% after initial fertilization. Although harsh chemical conditions (pH > 10) may have contributed to reduced abundance of pelagic Cladocera, Bosmina populations were also naturally variable prior to manipulation. Changes in Bosmina morphology (mucrone, antennule, and carapace length) and cladoceran size ratios (Daphnia/[Daphnia + Bosmina]) suggested that zooplanktivory by fish and invertebrates exercised important control of herbivore populations. Fossil Bosmina concentration (remains∙[g dry wt]−1 or remains∙[g organic matter]−1) were significantly correlated (r = 0.66, P < 0.01, 1970–1989) to standing crop in the water column (animals∙m−2). Fossil accumulation rate (remains∙cm−2∙yr−1) was not significantly correlated to Bosmina abundance, perhaps because of errors in determining bulk sediment accumulation rates.

Distributions of Ferrous Iron and Sulfide in an Anoxic Hypolimnion

1984 ◽  
Vol 41 (2) ◽  
pp. 286-293 ◽  
Author(s):  
Robert B. Cook
Keyword(s):  
Pore Water ◽  
Solubility Product ◽  
Iron Sulfide ◽  
Water Flux ◽  
Sediment Pore Water ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Anoxic Hypolimnion ◽  
Decomposition Of Organic Matter

In the anoxic hypolimnion of Lake 227, Experimental Lakes Area, northwestern Ontario, ΣH2S exhibits a mid-depth maximum, while Fe2+ increases with depth. At the mid-depth ΣH2S maximum and below, saturation with respect to amorphous FeS is reached, and the concentration of ΣH2S is limited by the high Fe2+ concentrations, in accord with the FeS solubility product. Values for pKsp[Formula: see text] for FeS determined from the ΣH2S maximum and below averaged 3.16 in 1979 and agree well with other in situ and laboratory measurements. In the top 10 cm of sediment, pore water ΣH2S and Fe2+ are in equilibrium with amorphous FeS. Analyses of cores confirms the existence of an iron sulfide phase. Fe2+, which is produced in the pore water from the decomposition of organic matter, increases to concentrations at which siderite may form, although the presence of siderite has not been verified. Comparison of calculated pore water fluxes of Fe2+ with the observed increase of Fe2+ in the anoxic hypolimnion reveals that about 90% of the observed flux originates at the sediment–water interface, while the remainder is derived from pore water flux.

scholarly journals Source-receptor relationships for speciated atmospheric mercury at the remote experimental lakes area, Northwestern Ontario, Canada

2011 ◽  
Vol 11 (11) ◽  
pp. 31433-31474 ◽  
Author(s):  
I. Cheng ◽  
L. Zhang ◽  
P. Blanchard ◽  
J. A. Graydon ◽  
V. L. St. Louis
Keyword(s):  
Cluster Analysis ◽  
The United States ◽  
Atmospheric Mercury ◽  
Point Sources ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Photochemical Production ◽  
Combustion Emissions ◽  
Soil Emissions ◽  
Source Receptor Relationships

Abstract. Source-receptor relationships for speciated atmospheric mercury measured at the Experimental Lakes Area (ELA), Northwestern Ontario, Canada were investigated using various receptor-based approaches. The data used in this study include gaseous elemental mercury (GEM), mercury bound to fine airborne particles (< 2.5 μm) (PHg), reactive gaseous mercury (RGM), major inorganic ions, sulphur dioxide, nitric acid gas, ozone, and meteorological variables, all of which were measured between May 2005 and December 2006. The source origins identified were related to transport of industrial and combustion emissions (associated with elevated GEM), photochemical production of RGM (associated with elevated RGM), road-salt particles with adsorption of gaseous Hg (associated with elevated PHg and RGM), crustal/soil emissions, and background pollution. Back trajectory modelling illustrated that a remote site, like the ELA, is affected by distant Hg point sources in Canada and the United States. The sources identified from correlation analysis, principal components analysis and K-means cluster analysis were generally consistent. The discrepancies between the K-means and Hierarchical cluster analysis were the clusters related to transport of industrial/combustion emissions, photochemical production of RGM, and crustal/soil emissions. Although it was possible to assign the clusters to these source origins, the trajectory plots for the Hierarchical clusters were similar to some of the trajectories belonging to several K-means clusters. This likely occurred because the variables indicative of transport of industrial/combustion emissions were elevated in at least two or more of the clusters, which means this Hg source was well-represented in the data.

scholarly journals Source-receptor relationships for speciated atmospheric mercury at the remote Experimental Lakes Area, northwestern Ontario, Canada

2012 ◽  
Vol 12 (4) ◽  
pp. 1903-1922 ◽  
Author(s):  
I. Cheng ◽  
L. Zhang ◽  
P. Blanchard ◽  
J. A. Graydon ◽  
V. L. St. Louis
Keyword(s):  
Cluster Analysis ◽  
The United States ◽  
Atmospheric Mercury ◽  
Point Sources ◽  
Experimental Lakes Area ◽  
Northwestern Ontario ◽  
Photochemical Production ◽  
Combustion Emissions ◽  
Soil Emissions ◽  
Source Receptor Relationships

Abstract. Source-receptor relationships for speciated atmospheric mercury measured at the Experimental Lakes Area (ELA), northwestern Ontario, Canada were investigated using various receptor-based approaches. The data used in this study include gaseous elemental mercury (GEM), mercury bound to fine airborne particles (<2.5 μm) (PHg), reactive gaseous mercury (RGM), major inorganic ions, sulphur dioxide, nitric acid gas, ozone, and meteorological variables, all of which were measured between May 2005 and December 2006. The source origins identified were related to transport of industrial and combustion emissions (associated with elevated GEM), photochemical production of RGM (associated with elevated RGM), road-salt particles with absorption of gaseous Hg (associated with elevated PHg and RGM), crustal/soil emissions, and background pollution. Back trajectory modelling illustrated that a remote site, like ELA, is affected by distant Hg point sources in Canada and the United States. The sources identified from correlation analysis, principal components analysis and K-means cluster analysis were generally consistent. The discrepancies between the K-means and Hierarchical cluster analysis were the clusters related to transport of industrial/combustion emissions, photochemical production of RGM, and crustal/soil emissions. Although it was possible to assign the clusters to these source origins, the trajectory plots for the Hierarchical clusters were similar to some of the trajectories belonging to several K-means clusters. This likely occurred because the variables indicative of transport of industrial/combustion emissions were elevated in at least two or more of the clusters, which means this Hg source was well-represented in the data.

Performance of temperature and dissolved oxygen criteria to predict habitat use by lake trout (Salvelinus namaycush)This paper is part of the series “Forty Years of Aquatic Research at the Experimental Lakes Area”.

2009 ◽  
Vol 66 (11) ◽  
pp. 2011-2023 ◽  
Author(s):  
John M. Plumb ◽  
Paul J. Blanchfield
Keyword(s):  
Habitat Use ◽  
Dissolved Oxygen ◽  
Thermal Stratification ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Experimental Lakes Area ◽  
Lake Volume ◽  
Northwestern Ontario ◽  
Environmental Extremes

We compared theoretical habitat volumes, determined from traditional combinations of temperature and dissolved oxygen concentration (DO) boundaries, with in situ habitat use by acoustically tagged lake trout ( Salvelinus namaycush ). The widely used criteria of 8–12 °C underestimated lake trout habitat use by 68%–80%. Instead, combined temperature (<12 or 15 °C) and DO (>4 or 6 mg·L–1) criteria most closely matched lake trout habitat use, had a similar seasonal trend as the tagged fish, suggested modest reductions (5% of total lake volume) in habitat during a warmer year, and performed best when the constraints of temperature and DO were most limiting. All data were collected in a small boreal shield lake (27 ha, zmax = 21 m) at the Experimental Lakes Area in northwestern Ontario, Canada, during two contrasting periods of thermal stratification (2003: warmer and longer; 2004: cooler and shorter), providing an assessment of observed and theoretical habitat volumes over current environmental extremes.

Production of Epilithiphyton in Two Lakes of the Experimental Lakes Area, Northwestern Ontario

1973 ◽  
Vol 30 (10) ◽  
pp. 1511-1524 ◽  
Author(s):  
D. W. Schindler ◽  
V. E. Frost ◽  
R. V. Schmidt
Keyword(s):  
Liquid Scintillation ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Seasonal Effects ◽  
Algal Flora ◽  
Experimental Lakes Area ◽  
New Techniques ◽  
Natural Lakes ◽  
Northwestern Ontario

Two new techniques for measuring photosynthesis by benthic algal flora in waters low in dissolved inorganic carbon are described. The first uses gas chromatography to measure changes in DIC in incubation chambers directly. The second is a variation of the usual 14C procedure, in which disappearance of 14C from the water is measured by liquid scintillation instead of uptake of 14C by the algae. This procedure is simpler than measuring the uptake of 14C, because digestion and/or combustion of samples is not necessary. Results are compared with the commonly employed 14C uptake and O2 release techniques.Tests showed that heterogeneity of substrate was the major source of variation in in situ results, being large enough to make interpretation of seasonal effects and other causal factors extremely difficult.Annual production by epilithiphyton in two natural lakes in the Experimental Lakes Area (ELA) was 5.19 g C and 5.18 g C/m2 of substrate annually for lakes 239 and 240, respectively. These are the lowest values recorded for freshwater lakes at temperate latitudes.Because DIC and O2 concentrations could be measured simultaneously, it was possible to calculate photosynthetic quotients on several dates. These were extremely high, averaging 2.6 for the summer of 1971.

Optimal allocation of sampling effort in lake sediment studies

1995 ◽  
Vol 52 (10) ◽  
pp. 2146-2158 ◽  
Author(s):  
David J. Rowan ◽  
Joseph B. Rasmussen ◽  
Jacob Kalff
Keyword(s):  
Optimal Allocation ◽  
A Priori ◽  
Sediment Accumulation ◽  
Point Sources ◽  
Sampling Effort ◽  
Sediment Texture ◽  
Lake Morphometry ◽  
Accumulation Rates ◽  
Sediment Characteristics ◽  
Sediment Distribution

A sampling algorithm requiring only bathymetric and catchment parameters has been derived from several recent empirical developments and should drastically reduce the number of sites and replicates necessary to characterize the distribution, trace element concentrations, and sediment accumulation rates of lake sediments. A test of this algorithm with sediments from 96 sites in three basins of morphometrically complex Jack Lake, Ontario, demonstrates the utility of this approach. A priori application of the algorithm would have reduced the number of sample sites on our sampling grid from 96 to 22 (a reduction of 77%), without losing precision. This reduction in sample sites (and in time and money expended) would allow for sampling additional lakes or sites of local significance (e.g., river or creek mouths, pollution point sources), or measuring additional parameters. The relationships between lake morphometry, sediment distribution, and sediment texture, along with the relationships between sediment texture and inter- and intra-site variability, can also be used to extrapolate sediment characteristics from a few samples to the whole lake or to predict the zone to which sediment is focused.

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