Cyanobacterial blooms are expected to intensify and become more widespread with climate change and sustained nutrient pollution, subsequently increasing threats to lentic ecosystems, water quality, and human health. However, little is known about their rates of change because long‐term monitoring data are rare, except for some well‐studied individual lakes, which typically are large and broadly dispersed geographically. Using...

Freshwater reservoirs are an important source of the greenhouse gas methane (CH 4 ) to the atmosphere, but global emission estimates are poorly constrained (13.3–52.5 Tg C yr −1 ), partially due to extreme spatial variability in emission rates within and among reservoirs. Spatial heterogeneity in the availability of organic matter (OM) for biological CH 4 production by methanogenic archaea may be an important contributor to th...

Global estimates of methane (CH 4 ) emissions from reservoirs are poorly constrained, partly due to the challenges of accounting for intra‐reservoir spatial variability. Reservoir‐scale emission rates are often estimated by extrapolating from measurement made at a few locations; however, error and bias associated with this approach can be large and difficult to quantify. Here, we use a generalized random tessellation survey (G...

Nitrogen loading from developed watersheds to aquatic ecosystems can stimulate microbial denitrification, a process that reduces nitrate (NO − 3 ) to dinitrogen (N 2 ) or nitrous oxide (N 2 O), the latter a potent greenhouse gas. While aquatic ecosystems are a globally significant source of N 2 O to the atmosphere, the relationship between denitrification and N 2 O production is not well known. Until recently, this field of re...

We present a comprehensive data set of gross primary production (GPP) and ecosystem respiration (ER) in open‐canopy, nutrient‐rich streams draining row‐crop agriculture in the midwestern United States. We used two approaches to characterize temporal and spatial variation in whole‐stream metabolism: continuous measurements in one agricultural stream for 1 yr, and periodic daily measurements in six agricultural streams on six da...

We measured uptake length of 15 NO 3 − in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO 3 − uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural (reference), suburban‐urban, and agricultural land uses. Study streams spanned a range of human land use to maximiz...

We measured denitrification rates using a field 15 NO 3 − tracer‐addition approach in a large, cross‐site study of nitrate uptake in reference, agricultural, and suburban‐urban streams. We measured denitrification rates in 49 of 72 streams studied. Uptake length due to denitrification ( S Wden n) ranged from 89 m to 184 km (median of 9050 m) and there were no significant differences among regions or land‐use categories, likely...