Statistical testing of a new testate amoeba-based transfer function for water-table depth reconstruction on ombrotrophic peatlands in north-eastern Canada and Maine, United States

2012 ◽  
Vol 28 (1) ◽  
pp. 27-39 ◽  
Author(s):  
Matthew J. Amesbury ◽  
Gunnar Mallon ◽  
Dan J. Charman ◽  
Paul D. M. Hughes ◽  
Robert K. Booth ◽  
...  
Keyword(s):  
United States ◽  
Transfer Function ◽  
Water Table ◽  
Water Table Depth ◽  
Statistical Testing ◽  
Testate Amoeba ◽  
Eastern Canada ◽  
North Eastern ◽  
Depth Reconstruction

Evaluating a Canadian regional air quality model using ground-based observations in north-eastern Canada and United States

2002 ◽  
Vol 5 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Ray J. Yang ◽  
Adam G. Xia ◽  
Diane V. Michelangeli ◽  
David A. Plummer ◽  
Lori Neary ◽  
...  
Keyword(s):  
United States ◽  
Air Quality ◽  
Air Quality Model ◽  
Quality Model ◽  
Eastern Canada ◽  
North Eastern ◽  
Regional Air Quality

scholarly journals Estimation of Daily Water Table Level with Bimonthly Measurements in Restored Ombrotrophic Peatland

2021 ◽  
Vol 13 (10) ◽  
pp. 5474
Author(s):  
Sebastian Gutierrez Pacheco ◽  
Robert Lagacé ◽  
Sandrine Hugron ◽  
Stéphane Godbout ◽  
Line Rochefort
Keyword(s):  
Water Table ◽  
Linear Method ◽  
Estimation Method ◽  
Water Table Depth ◽  
Support Vector ◽  
Eastern Canada ◽  
Ombrotrophic Peatland ◽  
Daily Data ◽  
Daily Water ◽  
Potential Methods

Daily measurements of the water table depth are sometimes needed to evaluate the influence of seasonal water stress on Sphagnum recolonization in restored ombrotrophic peatlands. However, continuous water table measurements are often scarce due to high costs and, as a result, water table depth is more commonly measured manually bimonthly with daily logs in few reference wells. A literature review identified six potential methods to estimate daily water table depth with bimonthly records and daily measurements from a reference well. A new estimation method based on the time series decomposition (TSD) is also presented. TSD and the six identified methods were compared with the water table records of an experimental peatland site with controlled water table regime located in Eastern Canada. The TSD method was the best performing method (R2 = 0.95, RMSE = 2.48 cm and the lowest AIC), followed by the general linear method (R2 = 0.92, RMSE = 3.10 cm) and support vector machines method (R2 = 0.91, RMSE = 3.24 cm). To estimate daily values, the TSD method, like the six traditional methods, requires daily data from a reference well. However, the TSD method does not require training nor parameter estimation. For the TSD method, changing the measurement frequency to weekly measurements decreases the RMSE by 16% (2.08 cm); monthly measurements increase the RMSE by 13% (2.80 cm).

scholarly journals Spatial-temporal change in water table depth for the conterminous United States over three decades

2021 ◽  
Author(s):  
Holly Munro ◽  
Cristian Montes
Keyword(s):  
United States ◽  
Water Table ◽  
Anthropogenic Activities ◽  
Supply And Demand ◽  
Monitoring Network ◽  
Water Security ◽  
High Elevation ◽  
Water Table Depth ◽  
Boosted Regression Trees ◽  
Aquifer Systems

Abstract The subtle equilibrium between supply and demand of freshwater is constantly changing due to anthropogenic activities and shifts in land use and climate. These freshwater resources are crucial for food and water security, and the sustainability of natural and managed systems. The spatial-temporal properties of groundwater are often overlooked, despite these subsurface reservoirs being linked to aboveground water use and ecosystem processes. In this study, we assessed the spatial-temporal changes of water table depth in the conterminous United States (U.S.) over the last three decades (1989-2019). National Ground-Water Monitoring Network water table depth data were paired with climate and terrain features. Interpolated maps were created by combining machine learning (i.e., gradient boosted regression trees) with traditional interpolation methods (i.e., Kriging). Water table depth is shallower in the eastern U.S., as compared to western U.S., except for high elevation locals which consistently had deeper water tables. The overall change in depth to water table for the conterminous U.S. was ~1m indicating that on average the water is getting deeper. Of the 56 aquifer systems, 41 are in areas where the water table has gotten deeper. These results highlight current “hotspots” of possible depletion where water management efforts should focus. Management of this crucial resource is essential for mitigating negative impacts of depletion, which may ultimately feedback further amplifying changes in climate.

Why Do Testate Amoeba Optima Related to Water Table Depth Vary?

2018 ◽  
Vol 77 (1) ◽  
pp. 37-55 ◽  
Author(s):  
Irina V. Kurina ◽  
Hongkai Li
Keyword(s):  
Water Table ◽  
Water Table Depth ◽  
Testate Amoeba

scholarly journals Comparing and improving methods for reconstructing peatland water-table depth from testate amoebae

The Holocene ◽  
2019 ◽  
Vol 29 (8) ◽  
pp. 1350-1361
Author(s):  
Connor Nolan ◽  
John Tipton ◽  
Robert K Booth ◽  
Mevin B Hooten ◽  
Stephen T Jackson
Keyword(s):  
Water Table ◽  
Compositional Data ◽  
Testate Amoebae ◽  
Water Table Depth ◽  
Weighted Averaging ◽  
Training Dataset ◽  
Testate Amoeba ◽  
Test Case ◽  
Ecological Communities ◽  
Validation Experiment

Proxies that use changes in the composition of ecological communities to reconstruct temporal changes in an environmental covariate are commonly used in paleoclimatology and paleolimnology. Existing methods, such as weighted averaging and modern analog technique, relate compositional data to the covariate in very simple ways, and different methods are seldom compared systematically. We present a new Bayesian model that better represents the underlying data and the complexity in the relationships between species’ abundances and a paleoenvironmental covariate. Using testate amoeba–based reconstructions of water-table depth as a test case, we systematically compare new and existing models in a cross-validation experiment on a large training dataset from North America. We then apply the different models to a new 7500-year record of testate amoeba assemblages from Caribou Bog in Maine and compare the resulting water-table depth reconstructions. We find that Bayesian models represent an improvement over existing methods in three key ways: more complete use of the underlying compositional data, full and meaningful treatment of uncertainty, and clear paths toward methodological improvements. Furthermore, we highlight how developing and systematically comparing methods lead to an improved understanding of the proxy system. This paper focuses on testate amoebae and water-table depth, but the framework and ideas are widely applicable to other proxies based on compositional data.

Peat-based record from southern Patagonia shows centennial-scale variability since 4.2 ka

2021 ◽  
Author(s):  
Julie Loisel ◽  
Kristen Sarna
Keyword(s):  
Water Table ◽  
Atmospheric Carbon Dioxide ◽  
Deep Ocean ◽  
Testate Amoeba ◽  
Peat Core ◽  
Southern Patagonia ◽  
Depth Reconstruction ◽  
Late Twentieth ◽  
Southern Annual Mode ◽  
Carbon Dioxide Co2

<p>Here we present a 4200-year-old high-resolution peat core reconstruction from southern Patagonia. Our detailed carbon isotope (δ13C) record and testate amoeba-inferred water table depth reconstruction point to a progressive wetting of the peatland surface from 4200 to 1500 cal. yr BP, followed by a dry event at 1200-800 cal. yr BP and drier conditions since then. Superimposed on this trend are centennial-scale dips in δ13C values and water table depths that we associate with warm/dry spells. We interpret these shifts, which are akin to positive phases of the Southern Annual Mode (SAM), as reflecting century-scale changes in the Southern Westerly Wind belt during the late Holocene. Other records from southern South America and Tasmania have revealed synchronous changes in local vegetation and fire activity, strengthening our hypothesis. We know that millennial-scale shifts in the Westerly winds influence ocean upwelling in the Southern Ocean, with effects on global atmospheric carbon dioxide (CO2) concentrations. Our study, along with a few others, may help elucidate whether centennial-scale SAM-like shifts could also modulate the global carbon cycle via CO2 degassing from the deep ocean. This is important because instrumental and reanalysis records indicate strengthening and poleward contraction indicate a positive phase of the SAM since the late twentieth century.</p>

On a Polyhedral Disease of Trichiocampus viminalis (Fall.) Larvae (Hymenoptera: Tenthredinidae)

1959 ◽  
Vol 91 (6) ◽  
pp. 379-381 ◽  
Author(s):  
W. A. Smirnoff ◽  
R. Béique
Keyword(s):  
United States ◽  
British Columbia ◽  
Populus Nigra ◽  
Quebec City ◽  
Eastern United States ◽  
Eastern Canada ◽  
The Past ◽  
The North ◽  
North Eastern

The poplar sawfly, Trichiocampus viminalis Fall., is indigenous to Europe, where it is common and widespread, but is also prevalent in the north-eastern United States, Eastern Canada and British Columbia. For the past five or six years it has caused serious defoliation to Populus nigra and P. deltoides in the vicinity of Quebec City.

scholarly journals Temporal and Local Heterogeneities of Water Table Depth under Different Agricultural Water Management Conditions

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2148
Author(s):  
Jonathan A. Lafond ◽  
Silvio J. Gumiere ◽  
Virginie Vanlandeghem ◽  
Jacques Gallichand ◽  
Alain N. Rousseau ◽  
...  
Keyword(s):  
Water Management ◽  
Water Table ◽  
Cropping Systems ◽  
Irrigation Management ◽  
Sprinkler Irrigation ◽  
Water Table Depth ◽  
Management Systems ◽  
Integrated Water Management ◽  
Growing Seasons ◽  
Good Drainage

Integrated water management has become a priority for cropping systems where subirrigation is possible. Compared to conventional sprinkler irrigation, the controlling water table can lead to a substantial increase in yield and water use efficiency with less pumping energy requirements. Knowing the spatiotemporal distribution of water table depth (WTD) and soil properties should help perform intelligent, integrated water management. Observation wells were installed in cranberry fields with different water management systems: Bottom, with good drainage and controlled WTD management; Surface, with good drainage and sprinkler irrigation management; Natural, without drainage, or with imperfectly drained and conventional sprinkler irrigation. During the 2017–2020 growing seasons, WTD was monitored on an hourly basis, while precipitation was measured at each site. Multi-frequential periodogram analysis revealed a dominant periodic component of 40 days each year in WTD fluctuations for the Bottom and Surface systems; for the Natural system, periodicity was heterogeneous and ranged from 2 to 6 weeks. Temporal cross correlations with precipitation show that for almost all the sites, there is a 3 to 9 h lag before WTD rises; one exception is a subirrigation site. These results indicate that automatic water table management based on continuously updated knowledge could contribute to integrated water management systems, by using precipitation-based models to predict WTD.

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