Despite broad recognition of the value of the goods and services provided by nature, existing tools for assessing and valuing ecosystem services often fall short of the needs and expectations of decision makers. Here we address one of the most important missing components in the current ecosystem services toolbox: a comprehensive and generalizable framework for describing and valuing water quality-related services. Water quality is often misrepresented as a final ecosystem service. We argue that it is actually an important contributor to many different services, from recreation to human health. We present a valuation approach for water quality-related services that is sensitive to different actions that affect water quality, identifies aquatic endpoints where the consequences of changing water quality on human well-being are realized, and recognizes the unique groups of beneficiaries affected by those changes. We describe the multiple biophysical and economic pathways that link actions to changes in water qualityrelated ecosystem goods and services and provide guidance to researchers interested in valuing these changes. Finally, we present a valuation template that integrates biophysical and economic models, links actions to changes in service provision and value estimates, and considers multiple sources of water quality-related ecosystem service values without double counting. O ne of the fundamental challenges of mainstreaming ecosystem services into decision making involves linking ecosystem processes with changes in human well-being (1). This is especially true for water quality-related ecosystem goods and services. Water quality is highly valued by the public, and information on water quality values is increasingly demanded by decision makers. However, there is no generalizable framework for linking changes in water quality to changes in multiple ecosystem goods and services. This is problematic because limiting ecosystem service assessments to those services with direct use value and market prices systematically undervalues ecosystem services and fails to achieve a full accounting of all of the environmental and economic tradeoffs associated with decisions.Valuing water quality changes is particularly challenging relative to other ecosystem goods and services. Changing water quality affects many aspects of human well-being, and benefits and/or costs accrue to different groups of beneficiaries at varying spatial and temporal scales. This complexity contrasts with other ecosystem services, such as carbon sequestration, for which emissions are aggregated into a global atmospheric pool. Each unit increase in carbon emissions results in a more or less constant loss in value (i.e., costs associated with climate change). By contrast, each unit improvement in water quality may affect only a local area, the value of which varies widely with spatial context and may have strongly diminishing marginal benefits (e.g., additional reductions in nutrient pollution entering a clean lake generate minimal new benefits, and t...

[1] Riverine export of terrestrial organic carbon (TOC) plays an important role in the global C cycle through influences on coastal productivity, sedimentary preservation, and CO 2 efflux. In order to examine the influence of hydrologic variability and upland processes on TOC export from a midwestern agricultural watershed, we applied lignin phenol and stable carbon isotope analyses to assess quantity, source, and relative degradation state of TOC in soils, sediments, and size-fractioned aquatic OC from stream water. Flood conditions exported 90 times more dissolved organic carbon (DOC) than baseflow owing to increases in both discharge and concentration, indicating mobilization of additional DOC pools. These observations are supported by increased TOC contributions to aquatic OC during flooding. Furthermore, stable carbon isotope values show that OC exported during flooding is enriched in C 4 -derived C by up to 38% (for high molecular weight DOC) with respect to baseflow, indicating different TOC sources are mobilized dependant on hydrologic conditions. Lignin phenols isolated from the colloid size fraction show progressive increases in the ratio of carboxylic acid to aldehyde functional groups (a measure of relative degradation state) with distance downstream suggesting selective partitioning to mineral surfaces and/or degradation to this size fraction. This study shows that TOC quantity, source, and relative degradation state can change dependant on hydrologic conditions and in-stream transport in a small agricultural watershed. Moreover, these results are important in showing variability in TOC source and chemistry exported from headwater systems that might otherwise not be detected in studies of larger rivers.Citation: Dalzell, B. J., T. R. Filley, and J. M. Harbor (2005), Flood pulse influences on terrestrial organic matter export from an agricultural watershed,

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Current microbial source-tracking (MST) methods, employed to determine sources of fecal contamination in waterways, use molecular markers targeting host-associated bacteria in animal or human feces. However, there is a lack of knowledge about fecal microbiome composition in several animals and imperfect marker specificity and sensitivity. To overcome these issues, a community-based MST method has been developed. Here, we describe a study done in the Lake Superior-Saint Louis River estuary using SourceTracker, a program that calculates the source contribution to an environment. High-throughput DNA sequencing of microbiota from a diverse collection of fecal samples obtained from 11 types of animals (wild, agricultural, and domesticated) and treated effluent (n = 233) was used to generate a fecal library to perform community-based MST. Analysis of 319 fecal and environmental samples revealed that the community compositions in water and fecal samples were significantly different, allowing for the determination of the presence of fecal inputs and identification of specific sources. SourceTracker results indicated that fecal bacterial inputs into the Lake Superior estuary were primarily attributed to wastewater effluent and, to a lesser extent, geese and gull wastes. These results suggest that a community-based MST method may be another useful tool for determining sources of aquatic fecal bacteria.