title: Combined nutrient and macroalgae loads lead to response in seagrass indicator properties.
abstract: Excess nutrients are potential factors that drive phase shifts from seagrasses to macroalgae. We carried out a manipulative field experiment to study the effects of macroalgae Ulva pertusa loading and nutrient addition to the water column on the nitrogen (N) and carbon (C) contents (i.e., fast indicators) as well as on the morphology and structure (i.e., slow indicators) of Zostera marina. Our results showed rapid impact of increased macroalgae and nutrient load on Z. marina C/N ratios. Also, macroalgae addition resulted in a trend of decreasing belowground biomass of seagrasses, and nutrient load significantly decreased above to belowground biomass ratio. Although some morphological/structural variables showed relatively fast responses, the effects of short-term disturbance by macroalgae and nutrients were less often significant than on physiological variables. Monitoring of seagrass physiological indicators may allow for early detection of eutrophication, which may initiate timely management interventions to avert seagrass loss.
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Yantai, Shandong 264003, PR China. Electronic address: qyhan@yic.ac.cn.
authors.forename: Qiuying
authors.initials: Q
authors.lastname: Han
authors.affiliation: Spatial Ecology Department, Royal Netherlands Institute for Sea Research (NIOZ-Yerseke), P.O. Box 140, 4400 AC Yerseke, The Netherlands.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Soissons
authors.affiliation: Spatial Ecology Department, Royal Netherlands Institute for Sea Research (NIOZ-Yerseke), P.O. Box 140, 4400 AC Yerseke, The Netherlands.
authors.forename: Tjeerd J
authors.initials: TJ
authors.lastname: Bouma
authors.affiliation: Spatial Ecology Department, Royal Netherlands Institute for Sea Research (NIOZ-Yerseke), P.O. Box 140, 4400 AC Yerseke, The Netherlands; Department of Environmental Sciences, Institute for Wetland and Water Research, Faculty of Science, Radboud University Nijmegen, Nijmegen, Heijendaalseweg 135, 6525 AJ, The Netherlands.
authors.forename: Marieke M
authors.initials: MM
authors.lastname: van Katwijk
authors.affiliation: Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Yantai, Shandong 264003, PR China.
authors.forename: Dongyan
authors.initials: D
authors.lastname: Liu
mesh_terms: D018533:Biomass; D004784:Environmental Monitoring; D005068:Eutrophication; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D012624:Seaweed / Q000254:growth & development*; D044445:Ulva; D014873:Water Pollutants / Q000032:analysis; D035962:Zosteraceae / Q000502:physiology*
chemical_list: D014873:Water Pollutants; D010758:Phosphorus; D009584:Nitrogen
keywords: Eutrophication; Macroalgae suffocation; Seagrass–macroalgae interactions; Ulva pertusa; Zostera marina