Spatio-temporal variation of benthic metabolism in a large, regulated river

Abstract

Spatio-temporal patterns of benthic metabolism were measured to determine associations with substrate (cobble vs sand), channel location (main vs side channel), flow regulation (medium-head vs low-head) and temporal variability during the summer months. Benthic metabolism was estimated in two reaches of the Saint John River in New Brunswick, Canada using benthic chambers. General linear models indicated gross primary production (GPP) and community respiration (CR) was greater in cobble substrate in June, but only GPP was greater in July. CR differed between channel locations in July with greater rates in the side channel. Assessment of flow regulation showed greater GPP in the medium-head reach during July and August, but greater CR in July only. Regression analysis indicated temporal variation in GPP was associated with light, whereas CR was associated with GPP and water temperature. Results demonstrate that there are strong spatial and temporal trends for benthic metabolism in a large river.

Large dam renewals and removals—Part 1: Building a science framework to support a decision‐making process

“…Metrics need to capture drivers of natural variability, such as ecological responses to climate change impacts which may influence freshwater community function (Dossena et al, 2012; Poff & Olden, 2017). In addition to traditional community and population indicators, the baseline studies and data of MAES Phase I has begun to evaluate non‐traditional metrics (Palmer & Febria, 2012; Von Schiller et al, 2017) by building full food webs from the super site areas (using stable isotopes—Mor et al, 2018), exploring functional metrics such as metabolism (Irwin, 2017; Yates, Brua, Culp, Young, & Chambers, 2017), and testing eDNA and metabarcoding approaches (Deiner et al, 2017; O'Malley, 2018).…”