title: Multiple stressors and multifunctionality: limited effects on an illuminated benthic system.
abstract: The bulk of experiments that study stressor effects on ecosystem functioning consider only individual functions one at a time, and such narrow focus may well bias our understanding of the overall impact on ecosystem functioning. We used data from six published experiments in which marine illuminated sediment systems were exposed to nutrient enrichment, toxicants, sedimentation and warming, either alone or in combination. Measured functions were primary production, community respiration, inorganic nitrogen and phosphorus fluxes, and autotrophic biomass. We calculated two indices of multifunctionality that simultaneously considered all six functions: (i) a weighted average level of the functions and (ii) the number of functions that simultaneously exceed a critical threshold level. Stressors affected individual functions both positively and negatively, but multifunctionality was generally unaffected by both single and joint stressors. The filtering capacity of coastal illuminated sediment systems thus appears resilient to exposure to moderate levels of multiple stressors, most probably due to the robustness of the benthic microalgal community. We recommend using a multifunctionality approach in future studies on cumulative stressor effects on ecosystem functioning, particularly when considering functions related to ecosystem services.
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Göteborg 405 30, Sweden christian.alsterberg@bioenv.gu.se.
authors.forename: Christian
authors.initials: C
authors.lastname: Alsterberg
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Göteborg 405 30, Sweden.
authors.forename: Kristina
authors.initials: K
authors.lastname: Sundbäck
authors.affiliation: Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 461, Göteborg 405 30, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Gamfeldt
mesh_terms: D017753:Ecosystem; D008386:Marine Biology; D013312:Stress, Physiological
keywords: multifunctionality; multiple stressors; shallow-water sediment systems