Long-term water quality changes in a multiple-stressor system: a diatom-based paleolimnological study of Lake Simcoe (Ontario, Canada)

2012 ◽  
Vol 69 (1) ◽  
pp. 24-40 ◽  
Author(s):  
Jessica Hawryshyn ◽  
Kathleen M. Rühland ◽  
Roberto Quinlan ◽  
John P. Smol
Keyword(s):  
Water Quality ◽  
Regional Climate ◽  
Sediment Cores ◽  
Phosphorus Loading ◽  
Diatom Assemblages ◽  
Late 20Th Century ◽  
System A ◽  
Multiple Stressor ◽  
Lake Simcoe

Diatom-based paleolimnological techniques were used to assess long-term changes in the water quality of Lake Simcoe (Ontario, Canada) using 210Pb-dated sediment cores from four sites across the lake. Modest lake-wide shifts in diatom community composition occurred in the late 19th and early 20th centuries, suggesting that early cultural disturbances (e.g., land clearance and canal construction) had relatively minor effects on Lake Simcoe water quality. However, starting in the 1930s, phosphorus loading to the lake increased, which was closely tracked by increases in diatom taxa indicative of eutrophic conditions. The most pronounced lake-wide shift in diatom assemblages occurred in the mid- to late 20th century, the nature and timing of which strongly suggested a response to regional climate warming. An additional and marked lake-wide shift in diatom assemblages occurred in the mid-1990s, coinciding with the invasion of dreissenid mussels in Lake Simcoe. Our results indicate that Lake Simcoe water quality has been affected by the interaction of numerous environmental stressors over the past two centuries, the complexity of which has been amplified by recent warming.

Impacts of agriculture on aquatic systems: lessons learnt and new unknowns in Northern Ireland

2001 ◽  
Vol 52 (1) ◽  
pp. 151 ◽  
Author(s):  
S. I. Heaney ◽  
R. H. Foy ◽  
G. J. A. Kennedy ◽  
W. W. Crozier ◽  
W. C. K. O' Connor
Keyword(s):  
Water Quality ◽  
Northern Ireland ◽  
Soluble Reactive Phosphorus ◽  
Phosphorus Loading ◽  
Phosphorus Concentration ◽  
The European Union ◽  
Blue Green Algae ◽  
Lough Neagh ◽  
The Impact

Agriculture in Northern Ireland depends on grass-based production, but since 1980, expansion of output has been effectively constrained by production limits set by the European Union agricultural policy. Despite this, long-term monitoring over several decades has shown significant degradation of water quality in Lough Neagh, with persistent high biomass of blue-green algae. Similar long-term studies have revealed a marked decline in the freshwater survival of salmon in the nearby River Bush. These changes may be related and reflect the impact of farming on water quality and salmonid production. Regular sampling of the inflowing rivers to Lough Neagh has shown that continued increase in lake phosphorus concentration has been primarily due to an increase in the soluble reactive phosphorus loading from agricultural diffuse sources. Similar diffuse inputs of agriculturally derived nutrients to the River Bush, leading to increased plant growth together with the accumulation of fine sediment in salmon spawning redds, are considered to be important in the decline of freshwater survival of salmon from egg to smolt. The impact of farming practices on lakes and rivers is considered in relation to understanding of the complex and interacting factors that link land use to water quality.

Long-term changes in the water quality of a deep temperate oligotrophic lake in response to catchment disturbance: evidence from sediment cores

2019 ◽  
Vol 53 (4) ◽  
pp. 571-587 ◽  
Author(s):  
Alfred Theodore N. K. Kpodonu ◽  
David P. Hamilton ◽  
Christopher H. Lusk ◽  
Adam Hartland ◽  
Daniel C. Laughlin ◽  
...  
Keyword(s):  
Water Quality ◽  
Sediment Cores ◽  
Oligotrophic Lake ◽  
Catchment Disturbance ◽  
Long Term Changes

Long-term water quality monitoring in Lake Simcoe based on the empirical method and machine learning

2021 ◽  
Author(s):  
Bo Wang ◽  
Jinhui Huang ◽  
Hongwei Guo
Keyword(s):  
Machine Learning ◽  
Water Quality ◽  
Chlorophyll A ◽  
Total Phosphorus ◽  
Water Quality Monitoring ◽  
Quality Parameters ◽  
Empirical Method ◽  
Quality Monitoring ◽  
Lake Simcoe

<p><strong>Abstract:</strong> The traditional water quality monitoring methods are time-consuming and laborious, which can only reflect the water quality status of single point scale, and have some problems such as irregular sampling time and limited sample size. Remote sensing technology provides a new idea for water quality monitoring, and the temporal resolution of MODIS is one day, which is suitable for long-term, continuous real-time large-scale monitoring of lakes. In this study, Lake Simcoe (located in Ontario, Canada) was selected as the research area. The long-term spatiotemporal changes of chlorophyll-a, transparency, total phosphorus and dissolved oxygen were analyzed by comparing the empirical method, multiple linear regression, random forest and neural network with MODIS data. Finally, the water quality condition of Lake Simcoe is evaluated. The results show that the overall retrieval results of two machine learning models are better than that of the empirical method. The optimal retrieval accuracy R² for four water quality parameters are 0.976, 0.988, 0.943, 0.995, and RMSE are 0.13μg/L, 0.3m, 0.002mg/L and 0.14mg/L, respectively. On the annual scale, the annual mean values of the four water quality parameters during the 10-year period from 2009 to 2018 were 1.37μg/L, 6.9m, 0.0112mg/L and 10.17mg/L, respectively. On the monthly scale, chlorophyll a, total phosphorus and dissolved oxygen first decreased and then increased at the time of year. The higher concentrations of chlorophyll a and total phosphorus in the south and east of Lake Simcoe are related to the input of nutrients from the surrounding residents and farmland.</p><p><strong>Key words: </strong>water quality monitoring; MODIS; empirical method; machine learning</p>

Performance of deep learning in mapping water quality of Lake Simcoe with long-term Landsat archive

2022 ◽  
Vol 183 ◽  
pp. 451-469
Author(s):  
Hongwei Guo ◽  
Shang Tian ◽  
Jinhui Jeanne Huang ◽  
Xiaotong Zhu ◽  
Bo Wang ◽  
...  
Keyword(s):  
Water Quality ◽  
Deep Learning ◽  
Lake Simcoe

Postsettlement eutrophication histories of six British Columbia (Canada) lakes

1995 ◽  
Vol 52 (11) ◽  
pp. 2388-2401 ◽  
Author(s):  
Euan D. Reavie ◽  
John P. Smol ◽  
N. Bruce Carmichael
Keyword(s):  
British Columbia ◽  
Transfer Function ◽  
Total Phosphorus ◽  
Sediment Cores ◽  
Nutrient Inputs ◽  
Diatom Assemblages ◽  
European Settlement ◽  
Lake Systems ◽  
Phosphorus Levels

Eutrophication is a serious problem in many British Columbia lakes. However, long-term nutrient data are rare or unavailable for most lake systems, so the natural, predisturbance characteristics of lakes are unknown, as are the trajectories of past environmental change. We used paleolimnological analyses of diatoms to quantitatively assess eutrophication trends for approximately the last 150 years in six British Columbia lakes. A transfer function was used to infer past lake-water total phosphorus concentrations from the sedimentary diatom assemblages in 210Pb-dated sediment cores: all of the lakes had relatively high total phosphorus levels (> 13 μg/L) prior to European settlement. Three of the lakes showed significant eutrophication since that time, whereas the others were only mildly affected. Total phosphorus inferences using the transfer function satisfactorily estimated the modern total phosphorus concentrations of our six study lakes. Minor quantitative problems arose when some fossil assemblages provided poor analogues to the calibration function, but eutrophication trends were still clearly apparent. Our results confirm that some British Columbia lakes have suffered considerable eutrophication as a result of anthropogenically related nutrient inputs, while others, although situated within human-influenced regions, have been relatively unaffected. These results can now be used to help set realistic goals for restoration projects.

Water-quality trends using sediment cores from White Rock Lake, Dallas, Texas

Fact Sheet ◽  
1996 ◽  
Author(s):  
Peter C. Van Metre ◽  
Larry F. Land ◽  
C.L. Braun
Keyword(s):  
Water Quality ◽  
Sediment Cores ◽  
Water Quality Trends ◽  
Rock Lake
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