title: Practical considerations for addressing uncertainties in monitoring bulk deposition.
abstract: The assessment of the deposition of both wet (rain and cloud) and dry sedimenting particles is a prerequisite for estimating element fluxes in ecosystem research. Many nations and institutions operate deposition networks using different types of sampler. However, these samplers have rarely been characterized with respect to their sink properties. Major errors in assessing bulk deposition can result from poor sampling properties and defective sampling strategies. Relevant properties are: sampler geometry and material, in particular the shape of the rim; sink properties for gases and aerosols; and microbial transformations of the collected samples. An adequate number of replicates allows the identification of samples which are contaminated, in particular by bird droppings. The paper discusses physical and chemical properties of the samplers themselves. The dependence of measurement accuracy on the number of replicates and the sampling area exposed is discussed. Recommendations are given for sampling strategies, and for making corrections and substitution of missing data.
authors.affiliation: Institute of Agroecology, Federal Agricultural Research Centre, Bundesallee 50, D-38116 Braunschweig, Germany. ulrich.daemmgen@fal.de
authors.forename: Ulrich
authors.initials: U
authors.lastname: Dämmgen
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: Erisman
authors.forename: J Neil
authors.initials: JN
authors.lastname: Cape
authors.forename: Ludger
authors.initials: L
authors.lastname: Grünhage
authors.forename: David
authors.initials: D
authors.lastname: Fowler
mesh_terms: D000397:Air Pollution; D017753:Ecosystem; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D004787:Environmental Pollution; D011891:Rain; D012680:Sensitivity and Specificity; D012987:Soil; D014877:Water Pollution, Chemical
chemical_list: D012987:Soil