Interregional comparisons of sediment microbial respiration in streams

Abstract

Summary The rate of microbial respiration on fine‐grained stream sediments was measured at 371 first to fourth‐order streams in the Central Appalachian region (Maryland, Pennsylvania, Virginia, and West Virginia), Southern Rocky Mountains (Colorado), and California's Central Valley in 1994 and 1995. Study streams were randomly selected from the United States Environmental Protection Agency's (USEPA) River Reach File (RF3) using the sample design developed by USEPA's Environmental Monitoring and Assessment Program (EMAP). Respiration rate ranged from 0 to 0.621 g O2 g‐1 AFDM h‐1 in Central Appalachian streams, 0‐0.254 g O2 g‐1 AFDM h‐1 in Rocky Mountain streams, and 0‐0.436 g O2 g‐1 AFDM h‐1 in Central Valley streams. Respiration was significantly lower in Southern Rocky Mountain streams and in cold water streams (< 15 °C) of the Central Appalachians. Within a defined index period, respiration was not significantly different between years, and was significantly correlated with stream temperature and chemistry (DOC, total N, total P, K, Cl, and alkalinity). The uniformity of respiration estimates among the three study regions suggests that sediment microbial respiration may be collected at any number of scales above the site‐level for reliable prediction of respiration patterns at larger spatial scales.

Carbon and nitrogen cycling in a vegetated lowland chalk river impacted by sediment

“…Our measurements of O 2 uptake agree well with those measured using benthic chambers similar to ours for three sites on a lowland river in Australia of 330-5672 µmol O 2 m 2 h 1 (Rees et al, 2005) and, despite methodological differences, with the mean of 963 µmol O 2 m 2 h 1 calculated by Hill et al (2000). Our annual mean rate of 8 mol O 2 m 2 y 1 (96 g C m 2 y 1 ) agrees with that predicted (127 g C m 2 y 1 ) for benthic respiration as a function of temperature by Sinsabaugh (1997).…”

“…Several authors have argued for the use of microbial processes as indicators of aquatic ecosystem integrity, and changes in such rates (e.g., respiration or carbon oxidation) may be indicative of environmental impacts (Hill et al, 2000). Our own results suggest that the high rates of carbon oxidation, especially in the spring, were not due to temperature variation or, for net growth to occur over the spring, autochthonous primary production.…”

Invertebrate and microbial responses to inundation in an ephemeral river reach in New Zealand: effects of preceding dry periods

“…Our results lend some support to this threshold concept: esterase activity decreases sharply over a narrow range of dry periods, but the temporal resolution of our sediment moisture measurements was too coarse to identify the moisture threshold. Sediment respiration rates reported for saturated stream sediments range from 0.03-31 mg O 2 g AFDM POM -1 h -1 , and vary with temperature, dissolved nutrient concentrations, organic matter content and microbial biomass (Jones et al, 1995;Hill et al, 2000;Uehlinger et al, 2003). The range of sediment respiration rates in our no-inundation experiments (0.05-0.8 mg O 2 g AFDM POM -1 h -1 ) is in the low end of the range for saturated sediments, and may reflect lower microbial biomass and sediment organic matter, and the scarcity of dissolved nutrients in ephemeral river sediments.…”

Temporal variation in organic carbon spiraling in Midwestern agricultural streams

“…We quantified turnover rates of organic carbon using two approaches: (1) the open-water exchange method of measuring whole-stream metabolism (Odum 1956;Bott 2006), and (2) substrate-specific heterotrophic respiration on accumulations of fine organic particles (Hill et al 1998(Hill et al , 2000. We employed both of these approaches in our study design as they quantify heterotrophic respiration at different spatial and temporal scales, and with different respective advantages and caveats (see Young et al 2008;Tank et al 2010 for discussion).…”