title: Aquatic subsidies transport anthropogenic nitrogen to riparian spiders.
abstract: Stable nitrogen isotopic composition (δ15N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in δ15N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider δ15N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size.
authors.affiliation: Department of Environmental Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan. f-akamt55@pwri.go.jp
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Akamatsu
authors.forename: Hideshige
authors.initials: H
authors.lastname: Toda
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000737:chemistry; D049628:Body Size; D002247:Carbon Isotopes / Q000032:analysis; D004032:Diet; D020387:Food Chain; D007313:Insecta / Q000737:chemistry; D007564:Japan; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000032:analysis; D013112:Spiders / Q000737:chemistry / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*; D014876:Water Pollution
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D014874:Water Pollutants, Chemical; D009584:Nitrogen