Canopy interception, stemflow and streamflow on a small drainage in the Missouri Ozarks

Digitized 2007 AES MoU.Includes bibliographical references (page 26)

Atmospheric deposition of organic carbon via precipitation

AbstractAtmospheric deposition is the major pathway for removal of organic carbon (OC) from the atmosphere, affecting both atmospheric and landscape processes. Transfers of OC from the atmosphere to land occur as wet deposition (via precipitation) and as dry deposition (via surface settling of particles and gases). Despite current understanding of the significance of organic carbon inputs with precipitation to carbon budgets, transfers of organic matter between the atmosphere and land are not explicitly included in most carbon cycle models due to limited data, highlighting the need for further information. Studies regarding the abundance of OC in precipitation are relatively sparse, in part due to the fact that concentrations of organics in precipitation and their associated rates of atmospheric deposition are not routinely measured as a part of major deposition monitoring networks. Here, we provide a new data synthesis from 83 contemporary studies published in the peer reviewed literature where organic matter in precipitation was measured around the world. We compiled data regarding the concentrations of organic carbon in precipitation and associated rates of atmospheric deposition of organic carbon. We calculated summary statistics in a common set of units, providing insights into the magnitude and regional variability of OC in precipitation. A land to ocean gradient is evident in OC concentrations, with marine sites generally showing lower values than continental sites. Our synthesis highlights gaps in the data and challenges for data intercomparison. There is a need to concentrate sampling efforts in areas where anthropogenic OC emissions are on the rise (Asia, South America), as well as in remote sites suggesting background conditions, especially in Southern Hemisphere. It is also important to acquire more data for marine rainwater at various distances from the coast in order to assess a magnitude of carbon transfer between the land and the ocean. Our integration of the recent published information on OC in precipitation provides a unique data set (shared here as supplemental information) and a regional perspective that will be useful in carbon budgets, environmental modeling, and ecosystem studies. This can be used for comparison with past conditions and as a baseline toward exploring future changes, since changes in emissions, land use, and climatic variability are reflected in the amount and quality of OC deposited to ecosystems

Soil Chemical Response to Experimental Acidification Treatments

One of the conclusions reached during the Congressionally mandated National Acid Precipitation Program (NAPAP) was that, compared to ozone and other stress factors, the direct effects of acidic deposition on forest health and productivity were likely to be relatively minor. However, the report also concluded “the possibility of long-term (several decades) adverse effects on some soils appears realistic” (Barnard et al. 1990). Possible mechanisms for these long-term effects include: (1) accelerated leaching of base cations from soils and foliage, (2) increased mobilization of aluminum (Al) and other metals such as manganese (Mn), (3) inhibition of soil biological processes, including organic matter decomposition, and (4) increased bioavailability of nitrogen (N)

Vegetation and Acidification

In this chapter, the impact of watershed acidification treatments on WS3 at the Fernow Experimental Forest (FEF) and at WS9 on vegetation is presented and summarized in a comprehensive way for the first time. WS7 is used as a vegetative reference basin for WS3, while untreated plots within WS9 are used as a vegetative reference for WS9. Bioindicators of acidification impacts that will be considered include several measures of tree and stand growth rates, foliar chemistry, bolewood chemistry, and herbaceous species composition and diversity. These studies enhance our understanding of the inter-relationships of changes in soil conditions caused by the acidification treatment and the condition of forest vegetation

Pumping Alkaline Groundwater to Restore a Put-And-Take Trout Fishery in a Stream Acidified by Atmospheric Deposition

The purpose of this study was to pump alkaline groundwater into Linn Run in southwestern Pennsylvania to neutralize acidity, reduce dissolved aluminum concentrations, and protect stocked brown trout Salmo trutta and brook trout Salvelinus fontinalis during the springs of 1985 and 1986. A regression model was used to estimate the groundwater volume needed to maintain predetermined stream pH levels for a given streamflow. Equal numbers of brook and brown trout were stocked in a treatment stream section influenced by the wells and a naturally alkaline downstream reference section before and during the fishing season each year. Groundwater addition increased mean stream pH from 4.9 upstream of the wells to 6.0 in the treatment section and reduced mean dissolved aluminum from 0.36 mg/L to 0.03 mg/L above and below the wells, respectively. A large runoff episode following the 1985 preseason stocking overwhelmed the capacity of the wells to neutralize Linn Run, causing at least 25% mortality and reducing the catch rate of brown trout in the treatment section. No mortality of caged trout occurred in the treatment section except during this large runoff event. However, mortality was rapid for caged trout upstream of the wells; median survival times were 67 and 29 h for brook and brown trout, respectively. Otherwise, angler catch rates and trout harvest were not significantly different between the treated and reference sections. Electrofishing surveys revealed greater downstream than upstream movement of stocked trout, which may indicate a response to water chemistry. Alkaline groundwater additions also caused an increase in the density of native brook trout in the treatment section via upstream migration from downstream refuges influenced by groundwater. © 1989 Taylor and Francis Group, LLC