scholarly journals Headwater lakes and their influence on downstream discharge

2019 ◽  
Vol 4 (4) ◽  
pp. 105-112 ◽  
Author(s):  
Jason A. Leach ◽  
Hjalmar Laudon
Keyword(s):  
Headwater Lakes

Organochlorine Residues in Brook Trout and Yellow Perch From New Brunswick and Nova Scotia (Canada) Lakes

1987 ◽  
Vol 22 (3) ◽  
pp. 352-364
Author(s):  
R. Peterson ◽  
S. Ray
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Brook Trout ◽  
Yellow Perch ◽  
Intensive Agriculture ◽  
Fish Tissues ◽  
North Central ◽  
Ddt Metabolites ◽  
Headwater Lakes

Abstract Brook trout and yellow perch collected while surveying New Brunswick and Nova Scotia headwater lakes were analyzed for DDT metabolites, chlordane, hexacyclohexane isomers, hexachlorobenzene, toxaphene and PCB’s. Concentrations of DDT metabolites were much higher from fish taken from lakes in north-central N.B. (200-700 ng/g wet wt) than from fish taken elsewhere (<10 ng/g). Seventy to 90% of the DDT metabolites was DDE. Chlordane (3-13 ng/g) was analyzed in seven trout, six of them from central N.B. areas with intensive agriculture. Isomers of hexachlorocyclohexane were in highest concentration from north-central N.B. (10-20 ng/g), eastern N.S. (5-15 ng/g) and southern N.B. (5-20 ng/g). In most cases, alpha-hexachlorocyclohexane (lindane) was the isomer in highest concentration. Concentrations of hexachlorobenzene in fish tissues was highly variable with no obvious geographic bias. PCB’s were detected in very few fish, and no toxaphene was detected.

Factors influencing the achievement of steady state in mercury contamination among lakes and catchments of south-central Ontario

2009 ◽  
Vol 66 (2) ◽  
pp. 187-200 ◽  
Author(s):  
R. Brad Mills ◽  
Andrew M. Paterson ◽  
Jules M. Blais ◽  
David R.S. Lean ◽  
John P. Smol ◽  
...  
Keyword(s):  
Organic Matter ◽  
Steady State ◽  
Annual Runoff ◽  
Model Fit ◽  
Mercury Contamination ◽  
Positive Linear Relationship ◽  
South Central ◽  
Factors Influencing ◽  
Headwater Lakes ◽  
Drainage Ratio

Mercury (Hg) concentrations in recent (0.5–1 cm) and preindustrial (>30 cm) sediments were examined across lakes in south-central and eastern Ontario, Canada (45.53°N, 82.41°W to 44.15°N, 76.25°W), to determine whether Hg exported from watersheds is at steady state with atmospheric deposition. An examination of headwater lakes revealed that Hg enrichment was not uniform among watersheds but that the enrichment factor (EF = [Hg]present day/[Hg]preindustrial, standardized for organic matter) decreased as a function of drainage ratio (Ad /Ao, watershedarea/lakearea). Furthermore, the model fit was improved after accounting for differences in sulfate concentrations and pH among lakes: EF = (Ad /Ao)–15.96 – 0.07(SO 42– ) – (3.55(pH>8.3)) (R2 = 0.458, p = 0.0001). Hg concentrations in preindustrial sediments of headwater lakes showed a positive linear relationship with drainage ratio (partial t = 4.83, p < 0.0001, n = 66) that was strengthened following an adjustment for mean annual runoff (MAR) ([Hg]preindustrial = 0.011 ± 0.002(Ad /Ao) + 0.0008 ± 0.0003(MAR) (R2 = 0.108, F[1,66] = 8.01, p = 0.006)). Our results suggest that Hg export from watersheds may be currently lagging behind atmospheric Hg deposition, in which case, Hg export would increase into the future, even as Hg deposition from the atmosphere stabilizes.

Zooplankton Diversity and Biomass in Recently Acidified Lakes

1983 ◽  
Vol 40 (1) ◽  
pp. 36-42 ◽  
Author(s):  
John L. Confer ◽  
Thomas Kaaret ◽  
Gene E. Likens
Keyword(s):  
New York ◽  
New Hampshire ◽  
Entire Range ◽  
New York State ◽  
Adirondack Mountains ◽  
White Mountains ◽  
Ph Values ◽  
Headwater Lakes ◽  
Negative Effect ◽  
Mesocyclops Edax

Ten small headwater lakes in the Adirondack Mountains of New York State and 10 in the White Mountains of New Hampshire were examined for possible effects of acidification on zooplankton. The results showed that acidification, or some close correlate, had a significant negative effect on zooplankton diversity and biomass. A loss of 2.4 species of zooplankton and 22.6 mg dry wt/m2 was correlated with each unit decrease in pH. These results, in contrast to some previous work, show a continuous decrease in diversity and biomass over the entire range of pH in the sampled lakes, 4.5–7.2. Cladocera, with the exception of Holopedium and Polyphemus, and Epischura lacustris, Mesocyclops edax, and Cyclops scutifer, were abundant at higher pH values but rare or absent at pH values less than 5. Diaptomus minutus was predominant at pH values less than 5.Key words: acid rain, lakes, Adirondack Mountains, White Mountains, zooplankton, Cladocera, Epischura, Mesocyclops, Cyclops, Diaptomus

Simulation of Climate Change Effects on Hydropower Operations in Mountain Headwater Lakes, New Zealand

2016 ◽  
Vol 33 (1) ◽  
pp. 147-161 ◽  
Author(s):  
B. S. Caruso ◽  
R. King ◽  
S. Newton ◽  
C. Zammit
Keyword(s):  
Climate Change ◽  
New Zealand ◽  
Climate Change Effects ◽  
Headwater Lakes

Controls on greenhouse gas concentrations in polymictic headwater lakes in Ireland

2011 ◽  
Vol 410-411 ◽  
pp. 217-225 ◽  
Author(s):  
Colin J. Whitfield ◽  
Julian Aherne ◽  
Helen M. Baulch
Keyword(s):  
Greenhouse Gas ◽  
Headwater Lakes

Ancestry, population structure, and conservation genetics of Arctic grayling (Thymallus arcticus) in the upper Missouri River, USA

2009 ◽  
Vol 66 (10) ◽  
pp. 1758-1774 ◽  
Author(s):  
Douglas P. Peterson ◽  
William R. Ardren
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
River Basin ◽  
Genetic Relationships ◽  
Missouri River ◽  
Arctic Grayling ◽  
Headwater Lakes ◽  
Native Populations ◽  
Thymallus Arcticus ◽  
Two Populations

We genotyped Arctic grayling ( Thymallus arcticus ) at 10 microsatellite loci in 18 samples (n = 726) from Montana, Wyoming, and Saskatchewan to determine genetic relationships among native, captive, and naturalized populations in the upper Missouri River basin, to assess patterns in genetic diversity, and to infer recent demographic histories. Substantial genetic subdivision was observed among sample populations (global FST = 0.10). Canadian populations have been isolated from Missouri River populations long enough for mutation to cause genetic differences between regions (mean pairwise FST = 0.18, RST = 0.54). Within the Missouri River basin, most naturalized lacustrine populations traced their ancestry to Red Rock lakes. Two populations in headwater lakes within the Big Hole River watershed appear to be native. We found neither evidence for introgression of Canadian-origin grayling nor any effect of hatchery stocking in native populations. The native fluvial Big Hole River group was genetically distinct and most diverse (HE = 0.89), whereas native Madison River and Red Rock lakes populations exhibited lower genetic diversity (HE = 0.74 and 0.80, respectively) and evidence of recent bottlenecks. The existing Big Hole and Red Rock populations are at low abundance but do not appear to be at immediate risk of inbreeding depression (Ne = 207.7–228.2).

scholarly journals Dissolved organic carbon export and internal cycling in small, headwater lakes

2010 ◽  
Vol 24 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Edward G. Stets ◽  
Robert G. Striegl ◽  
George R. Aiken
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Carbon Export ◽  
Headwater Lakes ◽  
Internal Cycling
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