Algae and aquatic plants support river food webs through in-situ primary production. However, gross primary production (GPP) and ecosystem respiration (ER) are rarely evaluated in the context of river management or habitat restoration. We estimated daily GPP and ER during 2 growing seasons for 7 reaches in the Kootenai River and 1 reach in the Elk River, spanning 290 river km across British Columbia, Canada, and Montana and Idaho, USA. We characterized responses of GPP and ER to river management, including reaches with unregulated flow, regulated flow, nutrient addition, and habitat restoration. Downstream GPP and ER generally increased after changes in river management, and higher management intensity led to greater increases. GPP and ER followed a seasonal pattern with low initial values in spring, elevated values in mid-summer, and a return to low values in late summer and autumn. Timing and duration of the elevated period for GPP and ER also differed among reaches following changes in river management. Our results suggest that river management affects GPP and ER, likely through reducing turbidity and the frequency and magnitude of extreme flow events, nutrient additions, and enhanced floodplain connectivity, thereby altering the timing and amount of autochthonous carbon available to the food web.

Increased nutrient loading in aquatic environments can have a long-lasting influence on ecosystem processes and functions. The Kootenai River was historically oligotrophic, but nitrate levels have been steadily increasing since the mid-2000s, while phosphorus levels have remained low. Our study objective was to evaluate the current nutrient distribution throughout the Kootenai River watershed in the context of land use and land cover change. Each of the three land cover types we assessed, agriculture, developed areas, and surface mines, encompass less than 1% of the land area in the Kootenai River watershed. We measured nitrate, ammonium, and soluble reactive phosphorus (SRP) monthly at sites spanning 400 river km on the Kootenai River, and co-located tributary sites in British Columbia, Canada, and Montana and Idaho, USA. During July 2017, we measured the same nutrients along each of the selected tributaries with co-located sites at sub-catchment tributaries. Sites were selected to include a range of contributing drainage areas identified as agricultural, developed, or mining. Nutrient concentrations ranged from 0.012 to 4.

Objectives Sessile serrated adenomas with dysplasia (SSADs) of the colon are transitional lesions between sessile serrated adenomas (SSAs) and a subset of colorectal adenocarcinomas. We wished to gain insight into the relative percentages and significance of SSAD subtypes. Methods Retrospective (2007-2012) clinicopathologic review of colorectal polyps initially regarded as having mixed serrated and dysplastic elements. SSADs were subdivided into those with cap-like adenomatous dysplasia (ad1), non-cap-like adenomatous dysplasia (ad2), serrated dysplasia (ser), minimal dysplasia (min), and dysplasia not otherwise specified (nos). MLH1 immunostaining was performed on many. Results SSADser (7.7%) had a greater propensity for right colon, women, and MLH1 loss vs the entire cohort. SSAad1 (11.6%) had the least female preponderance, was least likely to have MLH1 loss, and was most likely to affect the left colorectum. SSAD with MLH1 loss was associated with an increased burden of SSAs in the background colon (P = .0003) but not tubular adenomas or hyperplastic polyps. Most SSADs (ad2 and nos groups, 80% combined) showed difficult-to-classify dysplasia, intermediate MLH1 loss rates, and intermediate clinical features. Conclusions While some trends exist, morphologically subclassifying SSADs is probably not justified in routine clinical practice. MLH1 loss portends a greater burden of SSAs in the background colon.