Concerns have been raised in the scientific community regarding the environmental implications of a dramatic increase in corn-based ethanol production and associated increases in pesticide use. The use of glyphosate, a broad-spectrum herbicide, for corn production has increased considerably in recent years in Canada and the United States. The cost of measuring concentrations of organic contaminants in the environment using traditional wet chemistry methods can be prohibitive; especiallywhen large numbers of samples are required to quantify the spatial and temporal variability in contaminant concentrations. The goal of our study was to evaluate a cost-effective method to measure glyphosate concentrations in surface waters. The reliability of enzyme-linked immunosorbent assay (ELISA) results was evaluated against liquid chromatography tandem mass spectrometry, and linear regression results for 30 water samples from urban watersheds revealed a strong relationship (R2 = 0.88). These results suggest that ELISA methods, used in conjunction with traditional methods, represent a cost-effective approach to enhance the spatial and temporal resolution of a water quality monitoring study. Additionally, we measured a total of 739 surface water samples from over 150 sampling locations throughout Ontario using ELISA from April to October 2007. Concentrations exceeded the method detection limit of 0.1 microg/L in 33% of the samples, with a maximum concentration of 12.0 microg/L. Glyphosate showed a bimodal temporal distribution with peak concentrations occurring in late spring/early summer and fall, and did not exceed the Canadian Council of Ministers of the Environment (CCME) guideline for the protection of aquatic life (65 microg/L) in any of the samples.

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It remains uncertain how the net ecosystem CO2 exchange (NEE) of diverse peatlands will respond to warming. Here we compare five years of eddy covariance measurements of NEE and estimates of gross primary productivity and ecosystem respiration between a fen dominated by deciduous vegetation and an adjacent bog with evergreen vegetation in the Canadian Hudson Bay Lowlands. At the bog, daily net CO2 uptake lasted from snowmelt to snow cover onset, while at the fen, net CO2 uptake was delayed in spring and ended earlier in fall. Greater midsummer net CO2 uptake at the fen compensated for shoulder season net CO2 losses resulting in similar annual NEE at the two sites (fen: −52 ± 16 g C m−2, bog: −80 ± 14 g C m−2). Observations of a satellite‐based productivity index also suggest lower shoulder season and higher peak vegetation productivity at these deciduous versus evergreen plant‐dominated peatlands. The response of NEE to warmer weather differed between sites. Warming during the shoulder seasons increased net CO2 uptake at the evergreen plant‐dominated bog, while it increased net CO2 losses at the fen where deciduous leaves had not yet emerged or had senesced. In contrast, warmer weather during the peak growing season appeared to reduce net CO2 uptake more at the bog than the fen resulting from both increasing ecosystem respiration and decreasing gross primary productivity. In the short term, warming will likely decrease annual net CO2 uptake of these and similar peatlands, although the magnitude will depend on factors including vegetation dynamics and seasonality of warming.