title: Risk assessment of nitrate and oxytetracycline addition on coastal ecosystem functions.
abstract: Diatoms dominate phytoplankton communities in the well-mixed coastal and upwelling regions. Coastal diatoms are often exposed to both aquaculture pollution and eutrophication. But how these exposures influence on coastal ecosystem functions are unknown. To examine these influences, a coastal centric diatom, Conticribra weissflogii was maintained at different concentrations of nitrate (N) and/or oxytetracycline (OTC). Algal density, cell growth cycle, protein, chlorophyll a, superoxide dismutase (SOD) activity, and malonaldehyde (MDA) were determined for the assessment of algal biomass, lifetime, nutritional value, photosynthesis and respiration, antioxidant capacity, and lipid peroxidation, respectively. When N addition was combined with OTC pollution, the cell growth cycles were shortened by 56-73%; algal density, SOD activities, the concentrations of chlorophyll a, protein, and MDA varied between 73 and 121%, 19 and 397%, 52 and 693%, 19 and 875%, and 66 and 2733% of the values observed in N addition experiments, respectively. According to P-value analysis, the influence of OTC on algal density and SOD activity was not significant, but the effect on cell growth cycle, protein, chlorophyll a, and MDA were significant (P<0.05). The influence of N addition with simultaneous OTC pollution on the above six end points was significant. Algal biomass, lifetime, nutrition, antioxidant capacity, lipid peroxidation, photosynthesis, and respiration were all affected by the addition of OTC and N. Coastal ecosystem functions were severely affected by N and OTC additions, and the influence was increased in the order: N<OTC<OTC+N. Thus, the simultaneous monitoring of N and OTC was necessary for the risk assessment of aquaculture pollution on coastal ecosystem functions.
authors.affiliation: Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Feng-Jiao
authors.affiliation: Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China. Electronic address: lishunxing@mnnu.edu.cn.
authors.forename: Li
authors.initials: L
authors.lastname: Shun-Xing
authors.affiliation: Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Feng-Ying
authors.affiliation: Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China; Fujian Province Key Laboratory of Modern Analytical Science and Separation Technology, Minnan Normal University, Zhangzhou 363000, China.
authors.forename: Huang
authors.initials: H
authors.lastname: Xu-Guang
authors.affiliation: Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, MA 02747, USA.
authors.forename: Zuo
authors.initials: Z
authors.lastname: Yue-Gang
authors.affiliation: Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China.
authors.forename: Tu
authors.initials: T
authors.lastname: Teng-Xiu
authors.affiliation: Department of Chemistry & Environmental Science, Minnan Normal University, Zhangzhou 363000, China.
authors.forename: Wu
authors.initials: W
authors.lastname: Xue-Qing
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D017377:Diatoms / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D017753:Ecosystem; D008315:Malondialdehyde / Q000378:metabolism; D009566:Nitrates / Q000633:toxicity*; D010118:Oxytetracycline / Q000633:toxicity*; D011156:Population Density; D018570:Risk Assessment; D013482:Superoxide Dismutase / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D009566:Nitrates; D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D008315:Malondialdehyde; D013482:Superoxide Dismutase; D010118:Oxytetracycline; D000077194:Chlorophyll A
keywords: Cell growth; Coastal diatiom; Coastal ecosystem function; Eutrophication; Oxytetracycline; Risk assessment