Brent J. Dalzell

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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(More)
Direct temperature-resolved mass spectrometry (DT-MS) was used to evaluate the molecular-level photodegradation of dissolved organic matter (DOM) isolated from three sites in a Chesapeake Bay subestuary (swamp- and marsh-influenced up-river, midestuarine, and bay mouth). From each site, filtered (<0.1 or <0.2 μm) water samples were irradiated in(More)
We performed laboratory studies to determine the effects of salinity on the photodegradation of dissolved organic matter (DOM) from the Great Dismal Swamp, Virginia, an important source of terrestrial DOM to the lower Chesapeake Bay. Samples were created by mixing Great Dismal Swamp water (ionic strength < 0 mol L21) with modified artificial seawater(More)
In this study, samples were taken from three contrasting freshwater sources and amended with salt in order to determine the influence of salinity and dissolved organic matter (DOM) composition on DOM recovery via ultrafiltration and solid phase extraction (SPE) with C18 disks. Salt addition caused variable recovery of DOM when using C18 SPE, and(More)
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(More)
Given an agricultural watershed containing a set of spatial units, and a set of land management practices, the Geodesign Optimization (GOP) aims to find a land management practice for each spatial unit that optimizes overall water quality improvements in the watershed under both budget constraint and spatial constraints (e.g., minimum contiguous area,(More)
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