Automated Routines for Calculating Whole-Stream Metabolism: Theoretical Background and User's Guide

Abstract

Automated routines for calculating whole-stream metabolism-Theoretical background and user's guide: U.S. Geological Survey Techniques and Methods 4-C2, 33 p. (online at http://pubs.water. usgs.gov/tm4c2/) iii Foreword The U.S. Geological Survey (USGS) is committed to providing the Nation with credible scientific information that helps to enhance and protect the overall quality of life and that facilitates effective management of water, biological, energy, and mineral resources (http:// www.usgs.gov/). Information on the Nation's water resources is critical to ensuring long-term availability of water that is safe for drinking and recreation and is suitable for industry, irrigation, and fish and wildlife. Population growth and increasing demands for water make the availability of that water, now measured in terms of quantity and quality, even more essential to the long-term sustainability of our communities and ecosystems. The USGS implemented the National Water-Quality Assessment (NAWQA) Program in 1991 to support national, regional, State, and local information needs and decisions related to water-quality management and policy (http://water.usgs.gov/nawqa). The NAWQA Program is designed to answer: What is the condition of our Nation's streams and ground water? How are conditions changing over time? How do natural features and human activities affect the quality of streams and ground water, and where are those effects most pronounced? By combining information on water chemistry, physical characteristics, stream habitat, and aquatic life, the NAWQA Program aims to provide science-based insights for current and emerging water issues and priorities. From 1991-2001, the NAWQA Program completed interdisciplinary assessments and established a baseline understanding of water-quality conditions in 51 of the Nation's river basins and aquifers, referred to as Study Units (http://water.usgs.gov/nawqa/studyu.html). Multiple national and regional assessments are ongoing in the second decade (2001-2012) of the NAWQA Program as 42 of the 51 Study Units are reassessed. These assessments extend the findings in the Study Units by determining status and trends at sites that have been consistently monitored for more than a decade, and filling critical gaps in characterizing the quality of surface water and ground water. For example, increased emphasis has been placed on assessing the quality of source water and finished water associated with many of the Nation's largest community water systems. During the second decade, NAWQA is addressing five national priority topics that build an understanding of how natural features and human activities affect water quality, and establish links between sources of contaminants, the transport of those contaminants through the hydrologic system, and the potential effects of contaminants on humans and aquatic ecosystems. Included are topics on the fate of agricultural chemicals, effects of urbanization on stream ecosystems, bioaccumulation of mercury in stream ecosystems, effects of nutrient enrichme...

Overcoming Equifinality: Leveraging Long Time Series for Stream Metabolism Estimation

“…Estimates of K 600 strongly affect estimates of GPP and ER (Bales & Nardi, ; Dugan et al, ). Our hierarchical partial‐pooling approach leverages multiday data sets to better inform estimates of K 600 and to choose among otherwise indistinguishable values of ER and GPP.…”

Comprehensive multiyear carbon budget of a temperate headwater stream

“…Recording periods lasted a minimum of 48 h. The DO exchange with the atmosphere (i.e., reaeration flux) was calculated based on the average DO saturation deficit in the reach, the oxygen transfer coefficient ( k O2 ), the travel time between the two stations, and stream discharge [ Young and Huryn , ]. Percent DO saturation was determined using DO concentration and temperature data [ Bales and Nardi , ] together with a standard altitude‐air pressure algorithm to correct for site altitude. During stream metabolic measurement campaigns, we measured photosynthetically active radiation data every 10 min using a LiCor 190SA sensor (LiCor Biosciences, Lincoln, NE, USA) connected to a Campbell Scientific logger.…”

The Temperature Dependence of the Carbon Cycle in Aquatic Ecosystems

“…Since it is impossible to directly measure R day , it was estimated, in keeping with the literature, by extrapolating the mean night time respiration value across the hours of daylight (Bales, 2007;Marzolf et al, 1994;Mulholland et al, 2001). ER was calculated as (see appendix details):…”

“…Photosynthetic dawn was identified as the minimum O 2 concentration after which all subsequent values were greater than it. Photosynthetic dusk was defined as the maximum O 2 concentration after which all subsequent values were lower (Bales and Nardi, 2007;Yvon-Durocher et al, 2010a). Each O 2 change value was then assigned to a day or night-time category.…”